AATS Annual Meeting

YES

I believe on-pump coronary artery bypass graft (CABG) surgery should be our primary operation, with off-pump CABG reserved only for certain situations.

In talking about these two surgical options, there are basically three main issues of interest: procedural outcomes, the quality of revascularization, and long-term effectiveness.

Procedural outcomes: In the 1990s, there was great excitement for the potential for off-pump CABG. We thought survival would be better, stroke less common, neurocognitive outcomes improved, etc., but after several randomized studies and a number of well-controlled observational studies, we found that, in terms of the important procedural outcomes – death, MI, stroke, and acute renal failure – there were actually no differences between off- and on-pump CABG. We saw this in ROOBY, with low-risk patients and less experienced surgeons; in the Canadian CORONARY trial, with experienced off-pump surgeons; and in the European GOPCABE trial, where the surgeons were very experienced and the patients were high risk.

There are some benefits with off-pump CABG in terms of what I call the "reversible" complications of surgery: fewer transfusions, less postoperative atrial fibrillation, fewer respiratory infections; but I believe these things have to be balanced against some of the negative effects of off-pump surgery in terms of its quality of revascularization and long-term effectiveness.

Probably one of the biggest disappointments we’ve had with off-pump CABG is that, in the trials, we didn’t see any major difference in neurocognitive dysfunction. What we learned is that cardiopulmonary bypass really is not that bad in terms of neurocognitive dysfunction after surgery.

One issue that tends to be forgotten is the risk associated with conversion. In a hemodynamically unstable patient, converting from off-pump to on-pump is associated with higher risks of death, bleeding, renal failure, stroke, respiratory failure, and GI complications. In CORONARY, with experienced surgeons, the conversion rate was almost 7.9%, and in GOPCABE, it was 9.7%. Even with experienced surgeons, conversions do occur, and they have negative consequences.

Quality of revascularization: We know that long-term survival is related to completeness of revascularization. The more ischemic myocardium that is left at risk after CABG, the more likely the patients is to have an MI or die, and this has been very clearly demonstrated in the surgical literature as well as the percutaneous coronary intervention literature. It has been shown multiple times that fewer grafts are done in off-pump patients, compared with on-pump patients. Indeed, in a recent Cochrane meta-analysis of more than 7,000 patients in 57 trials, there were significantly more grafts done in on-pump than off-pump cases.

Also in terms of graft patency, again, multiple studies have shown lower graft patency in off-pump patients, either directly or by means of showing a higher reintervention rate after off-pump as compared with on-pump surgery. In both CORONARY and GOPCABE, the repeat revascularization rate at 30 days was higher for off-pump CABG.

Long-term effectiveness: The long-term results from ROOBY are very sobering: significantly higher 1-year cardiac mortality in the off-pump arm and higher 1-year composite adverse events. Again, in the 2012 Cochrane meta-analysis, with more than 10,000 patients in 75 trials, mortality was significantly higher with off-pump patients, compared with on-pump, with a hazard ratio of 1.24 (95% CI, 1.01-1.53). When the authors of the Cochrane meta-analysis removed what they called the "studies with bias," this signal was even stronger. Also in observational studies, such as one published by Racz et al. in 2004 (J. Am. Coll. Cardiol. 2004; 43: 557-64), the best survival was found to be in patients who had on-pump CABG and the worst in those who had undergone off-pump CABG.

In summary, procedural outcomes with off-pump and on-pump CABG are similar, albeit with lower reversible complications in the off-pump patients, but a greater conversion risk, along with its associated complications. The quality of the revascularization is worse in off-pump patients, the completeness of revascularization is less and re-intervention rates are higher, and the bottom line, of course, it that there is higher long-term mortality after off-pump CABG.

"Should off-pump CABG be abandoned?" As our default procedure, yes. The vast majority of our patients are best served with on-pump revascularization.

Dr. Joseph Sabik is the chairman of the department of thoracic and cardiovascular surgery and the Sheik Hamdam Bin Rashid Al Maktoum Distinguished Chair at the Cleveland Clinic. He disclosed that he performs both off-pump and on-pump CABG.

References

Anesthesiology 2005;102:188-203

N. Engl. J. Med. 2009;361:1827-37

N. Engl. J. Med. 2012;366:1489-97

N. Engl. J. Med. 2013;368:1179-88

Cochrane Database Syst. Rev. 2012; Mar 14. 3: CD007224 [doi:10.1002/14651858.CD007224.pub2])

J. Am. Coll. Cardiol. 2004;43:557-64

NO

Should off pump bypass be abandoned? Absolutely not, but let’s do it well.

The rationale for why off-pump CABG should be the preferred strategy is simple: cardiopulmonary bypass (CPB) entails extracorporeal circulation, aortic cannulation and clamping, global MI, hypothermia, and hemodilution, among other potentially deleterious phenomena. There are morbidities that can be attributed to these entities, and off-pump bypass avoids those effects by mechanically stabilizing each coronary artery target individually, while the rest of the heart beats and supports normal physiologic circulation. There is an important caveat to this, however, and that is if – and perhaps only if – a complete revascularization with precise anastomoses can be accomplished off pump, then the patient will in fact benefit.

At Emory University in Atlanta, we did a prospective, randomized trial on my own patients, which we called SMART (Surgical Management of Arterial Revascularization) trial. What we found was that in 200 unselected, consecutive patients undergoing either off- or on-pump CABG, we had lower myocardial enzyme release, fewer transfusions, more rapid extubation, and a shorter length of stay in hospital with off-pump CABG.

Completeness of revascularization is a very important issue. In SMART, the number of grafts per patient was exactly the same: 3.39 per patient with off-pump CABG and 3.4 with on-pump CABG. We coined the phrase "Index of Completeness of Revascularization," which we defined as the number of grafts we planned to do in examining the arteriogram prior to randomization and surgery divided by the number of grafts we actually did. We found no difference here, meaning we were able to do the operation we planned to do (1.00 vs. 1.01; P = not significant). Moreover, for the lateral wall, which is technically more difficult to reach in a beating heart, the number was similar in the off- and on-pump groups (0.97 vs. 0.98; P = not significant). We also used a similar percentage of arterial grafts in both groups.

CPB was an independent predictor of the need for transfusion by multivariate analysis with an odds ratio of 2.42 (P = .0073) and was associated with a longer length of stay by 1 day (5.1 days for off-pump and 6.1 for on-pump; P = .005 Wilcoxon).

Creatine phosphokinase of muscle band and troponin I release was about half as much in the off-pump group as in the on-pump group (P less than .001 Wilcoxon), and the rates of death, stroke, MI, angina, and reintervention were similar at both 30 days and 1 year, as was graft patency and quality of life. Off-pump CABG costs at 1 year were $1,955 less than on-pump, but this difference was not statistically significant (P = .08).

At 8 years, survival in SMART was still similar between groups (P = .33), as was graft patency in the small number of patients who had CT angiograms. PET scan results similarly showed no significant difference in ischemia between these two groups (P = .62). One patient in each group has had a percutaneous reintervention, and none have had a repeat coronary bypass in 10 years.

To see if these results could be replicated nationally, we turned to the STS database and looked at North American centers that performed more than 100 on-pump CABGs and more than 100 off-pump surgeries. This gave us 42,477 patients (16,245 off pump and 26,232 on pump) at 63 North American centers. We included the 2.2% of off-pump cases that were converted to on-pump cases in the off-pump group.

After risk adjustment for 32 variables, for the outcomes of death, stroke, MI, and major adverse cardiac events, off-pump bypass outperformed on-pump bypass in this huge cohort of patients from around the country. Looking at less-significant outcomes – renal failure, dialysis, sternal infection, reoperation, atrial fibrillation, prolonged ventilation, and length of stay greater than 14 days – all of them favored off-pump bypass.

We then looked at the Emory dataset (14,766 consecutive patients, 48% of whom had off-pump CABG and 52% on-pump) to see which patients benefitted more. For patients in the two lower quartiles of predicted risk, there was no difference in operative mortality. In the higher two risk quartiles, there was a mortality benefit with off-pump CABG, with a risk reduction for operative mortality of about 55% in the highest risk patients (P less than 0.001).

Logistic regression confirmed that there was an interaction between surgery type and predicted risk, and we now know that low-risk patients do not have the survival benefit of avoiding CPB. They do fine with on-pump CABG, but higher risk patients have a benefit from avoiding CPB and the higher the predicted risk, the greater the benefit to the patient.

We went back to the STS database and we looked at whether this applies only at some centers or all centers, some surgeons or all surgeons. We looked at almost a million cases, 210,469 of which were at sites that had a large off-pump CABG volume. With the usual adjustments, off-pump CABG was associated with significant reduction of risk of death, stroke, renal failure, any morbidity or mortality or prolonged length of stay, compared with on-pump bypass. This benefit was even more pronounced after adjustment for surgeon effect. Once again, the greater reduction was enjoyed by those patients who had the highest preoperative risk. In all predicted risk quartiles, off pump bypass reduced risk of death and stroke and that magnitude increased with increasing predicted risk of mortality. This was seen in large-volume centers and low-volume centers.

Similar results were seen in a recent multicenter, randomized, prospective trial by Lemma et al. that assigned 411 patients to either off- or on-pump coronary bypass (J. Thorac. Cardiovasc. Surg. 2012;143:625-31). There was reduced early mortality and morbidity among higher-risk patients. Interestingly, in this study, they used an experience-based randomization scheme, in which they had surgeons within each center who like to do off-pump CABG and those who like to do on-pump CABG, and each surgeon had hundreds of cases under his belt. For the primary endpoint, a composite of death, MI, stroke or TIA, renal failure, acute respiratory distress syndrome, or reoperation for bleeding, the rates were 5.8% of off-pump and 13.3% for on-pump patients (odds ratio, 2.5; P = .01).

I think the conclusions are clear, but not everyone has reached these same conclusions. In ROOBY, the results were different. Although the study was well conducted, it enrolled low-risk patients, in whom avoidance of CPB was unlikely to improve the expected excellent outcomes. And the operations were performed by residents, with supervising attendings who themselves only had to do 20 total career off-pump cases to be eligible. I think this lack of experience is well demonstrated by the 12.5% conversion rate from off-pump cases to on-pump in that trial. ROOBY enrolled the wrong patients and used the wrong surgeons.

In the CORONARY trial, conducted by Dr. Lamy in Canada but enrolling patients from 19 countries outside of Canada, there was no difference in the primary endpoint of death, stroke, MI, and renal failure at 30 days, but there was a decrease in transfusion, reoperation for bleeding, acute kidney injury, or respiratory complications. There wasn\'t a difference in stroke, interestingly, but the surgeons in this trial appropriately converted a hundred patients from on pump to off pump to avoid manipulating a calcified aorta. This was a good, well-conducted trial.

However, the primary outcome in CORONARY differed when assessed according to EuroSCORE. When the EuroSCORE was low, on pump outperformed off pump. When the EuroSCORE was high, off pump outperformed on pump.

These two trials offer important perspective: the ROOBY trial, enrolling low-risk patients, was actually in favor of on-pump CABG. The CORONARY trial, enrolling higher-risk patients, had a slight benefit in favor of off-pump CABG, and this was particularly evident in the Canadian cohort of 830 randomized patients, in which the primary outcome was, in fact, statistically significantly better in the off-pump group at 9.2% vs. 13.7%.

At the end of the day, I think it matters in whom you do off-pump CABG and how well you do it. It may not be for every patient or for every surgeon; off-pump CABG requires a focused and sustained effort to master a new set of physical and psychological skills to accomplish precise and complete revascularization. When we can do this, I think, we offer better outcomes for our patients.

Dr. John Puskas is the chairman of the department of cardiac surgery at Mount Sinai Beth Israel in New York. Dr. Puskas disclosed that he also does both on- and off-pump CABG. He received royalties from coronary surgical instruments marketed by Scanlan, as well.

References

JAMA 2004;291:1841-9

Ann. Thorac. Surg. 2009;88:1142-7

N. Engl. J. Med. 2009;361:1827-37

N. Engl. J. Med. 2010;362:851

N. Engl. J. Med. 2012;366:1489-97

N. Engl. J. Med. 2013;368:1179-88

Ann. Thorac. Surg. 2011;91:1836-42

J. Thorac. Cardiovasc. Surg. 2012;143:625-31

YES

I believe on-pump coronary artery bypass graft (CABG) surgery should be our primary operation, with off-pump CABG reserved only for certain situations.

In talking about these two surgical options, there are basically three main issues of interest: procedural outcomes, the quality of revascularization, and long-term effectiveness.

Procedural outcomes: In the 1990s, there was great excitement for the potential for off-pump CABG. We thought survival would be better, stroke less common, neurocognitive outcomes improved, etc., but after several randomized studies and a number of well-controlled observational studies, we found that, in terms of the important procedural outcomes – death, MI, stroke, and acute renal failure – there were actually no differences between off- and on-pump CABG. We saw this in ROOBY, with low-risk patients and less experienced surgeons; in the Canadian CORONARY trial, with experienced off-pump surgeons; and in the European GOPCABE trial, where the surgeons were very experienced and the patients were high risk.

There are some benefits with off-pump CABG in terms of what I call the "reversible" complications of surgery: fewer transfusions, less postoperative atrial fibrillation, fewer respiratory infections; but I believe these things have to be balanced against some of the negative effects of off-pump surgery in terms of its quality of revascularization and long-term effectiveness.

Probably one of the biggest disappointments we’ve had with off-pump CABG is that, in the trials, we didn’t see any major difference in neurocognitive dysfunction. What we learned is that cardiopulmonary bypass really is not that bad in terms of neurocognitive dysfunction after surgery.

One issue that tends to be forgotten is the risk associated with conversion. In a hemodynamically unstable patient, converting from off-pump to on-pump is associated with higher risks of death, bleeding, renal failure, stroke, respiratory failure, and GI complications. In CORONARY, with experienced surgeons, the conversion rate was almost 7.9%, and in GOPCABE, it was 9.7%. Even with experienced surgeons, conversions do occur, and they have negative consequences.

Quality of revascularization: We know that long-term survival is related to completeness of revascularization. The more ischemic myocardium that is left at risk after CABG, the more likely the patients is to have an MI or die, and this has been very clearly demonstrated in the surgical literature as well as the percutaneous coronary intervention literature. It has been shown multiple times that fewer grafts are done in off-pump patients, compared with on-pump patients. Indeed, in a recent Cochrane meta-analysis of more than 7,000 patients in 57 trials, there were significantly more grafts done in on-pump than off-pump cases.

Also in terms of graft patency, again, multiple studies have shown lower graft patency in off-pump patients, either directly or by means of showing a higher reintervention rate after off-pump as compared with on-pump surgery. In both CORONARY and GOPCABE, the repeat revascularization rate at 30 days was higher for off-pump CABG.

Long-term effectiveness: The long-term results from ROOBY are very sobering: significantly higher 1-year cardiac mortality in the off-pump arm and higher 1-year composite adverse events. Again, in the 2012 Cochrane meta-analysis, with more than 10,000 patients in 75 trials, mortality was significantly higher with off-pump patients, compared with on-pump, with a hazard ratio of 1.24 (95% CI, 1.01-1.53). When the authors of the Cochrane meta-analysis removed what they called the "studies with bias," this signal was even stronger. Also in observational studies, such as one published by Racz et al. in 2004 (J. Am. Coll. Cardiol. 2004; 43: 557-64), the best survival was found to be in patients who had on-pump CABG and the worst in those who had undergone off-pump CABG.

In summary, procedural outcomes with off-pump and on-pump CABG are similar, albeit with lower reversible complications in the off-pump patients, but a greater conversion risk, along with its associated complications. The quality of the revascularization is worse in off-pump patients, the completeness of revascularization is less and re-intervention rates are higher, and the bottom line, of course, it that there is higher long-term mortality after off-pump CABG.

"Should off-pump CABG be abandoned?" As our default procedure, yes. The vast majority of our patients are best served with on-pump revascularization.

Dr. Joseph Sabik is the chairman of the department of thoracic and cardiovascular surgery and the Sheik Hamdam Bin Rashid Al Maktoum Distinguished Chair at the Cleveland Clinic. He disclosed that he performs both off-pump and on-pump CABG.

References

Anesthesiology 2005;102:188-203

N. Engl. J. Med. 2009;361:1827-37

N. Engl. J. Med. 2012;366:1489-97

N. Engl. J. Med. 2013;368:1179-88

Cochrane Database Syst. Rev. 2012; Mar 14. 3: CD007224 [doi:10.1002/14651858.CD007224.pub2])

J. Am. Coll. Cardiol. 2004;43:557-64

NO

Should off pump bypass be abandoned? Absolutely not, but let’s do it well.

The rationale for why off-pump CABG should be the preferred strategy is simple: cardiopulmonary bypass (CPB) entails extracorporeal circulation, aortic cannulation and clamping, global MI, hypothermia, and hemodilution, among other potentially deleterious phenomena. There are morbidities that can be attributed to these entities, and off-pump bypass avoids those effects by mechanically stabilizing each coronary artery target individually, while the rest of the heart beats and supports normal physiologic circulation. There is an important caveat to this, however, and that is if – and perhaps only if – a complete revascularization with precise anastomoses can be accomplished off pump, then the patient will in fact benefit.

At Emory University in Atlanta, we did a prospective, randomized trial on my own patients, which we called SMART (Surgical Management of Arterial Revascularization) trial. What we found was that in 200 unselected, consecutive patients undergoing either off- or on-pump CABG, we had lower myocardial enzyme release, fewer transfusions, more rapid extubation, and a shorter length of stay in hospital with off-pump CABG.

Completeness of revascularization is a very important issue. In SMART, the number of grafts per patient was exactly the same: 3.39 per patient with off-pump CABG and 3.4 with on-pump CABG. We coined the phrase "Index of Completeness of Revascularization," which we defined as the number of grafts we planned to do in examining the arteriogram prior to randomization and surgery divided by the number of grafts we actually did. We found no difference here, meaning we were able to do the operation we planned to do (1.00 vs. 1.01; P = not significant). Moreover, for the lateral wall, which is technically more difficult to reach in a beating heart, the number was similar in the off- and on-pump groups (0.97 vs. 0.98; P = not significant). We also used a similar percentage of arterial grafts in both groups.

CPB was an independent predictor of the need for transfusion by multivariate analysis with an odds ratio of 2.42 (P = .0073) and was associated with a longer length of stay by 1 day (5.1 days for off-pump and 6.1 for on-pump; P = .005 Wilcoxon).

Creatine phosphokinase of muscle band and troponin I release was about half as much in the off-pump group as in the on-pump group (P less than .001 Wilcoxon), and the rates of death, stroke, MI, angina, and reintervention were similar at both 30 days and 1 year, as was graft patency and quality of life. Off-pump CABG costs at 1 year were $1,955 less than on-pump, but this difference was not statistically significant (P = .08).

At 8 years, survival in SMART was still similar between groups (P = .33), as was graft patency in the small number of patients who had CT angiograms. PET scan results similarly showed no significant difference in ischemia between these two groups (P = .62). One patient in each group has had a percutaneous reintervention, and none have had a repeat coronary bypass in 10 years.

To see if these results could be replicated nationally, we turned to the STS database and looked at North American centers that performed more than 100 on-pump CABGs and more than 100 off-pump surgeries. This gave us 42,477 patients (16,245 off pump and 26,232 on pump) at 63 North American centers. We included the 2.2% of off-pump cases that were converted to on-pump cases in the off-pump group.

After risk adjustment for 32 variables, for the outcomes of death, stroke, MI, and major adverse cardiac events, off-pump bypass outperformed on-pump bypass in this huge cohort of patients from around the country. Looking at less-significant outcomes – renal failure, dialysis, sternal infection, reoperation, atrial fibrillation, prolonged ventilation, and length of stay greater than 14 days – all of them favored off-pump bypass.

We then looked at the Emory dataset (14,766 consecutive patients, 48% of whom had off-pump CABG and 52% on-pump) to see which patients benefitted more. For patients in the two lower quartiles of predicted risk, there was no difference in operative mortality. In the higher two risk quartiles, there was a mortality benefit with off-pump CABG, with a risk reduction for operative mortality of about 55% in the highest risk patients (P less than 0.001).

Logistic regression confirmed that there was an interaction between surgery type and predicted risk, and we now know that low-risk patients do not have the survival benefit of avoiding CPB. They do fine with on-pump CABG, but higher risk patients have a benefit from avoiding CPB and the higher the predicted risk, the greater the benefit to the patient.

We went back to the STS database and we looked at whether this applies only at some centers or all centers, some surgeons or all surgeons. We looked at almost a million cases, 210,469 of which were at sites that had a large off-pump CABG volume. With the usual adjustments, off-pump CABG was associated with significant reduction of risk of death, stroke, renal failure, any morbidity or mortality or prolonged length of stay, compared with on-pump bypass. This benefit was even more pronounced after adjustment for surgeon effect. Once again, the greater reduction was enjoyed by those patients who had the highest preoperative risk. In all predicted risk quartiles, off pump bypass reduced risk of death and stroke and that magnitude increased with increasing predicted risk of mortality. This was seen in large-volume centers and low-volume centers.

Similar results were seen in a recent multicenter, randomized, prospective trial by Lemma et al. that assigned 411 patients to either off- or on-pump coronary bypass (J. Thorac. Cardiovasc. Surg. 2012;143:625-31). There was reduced early mortality and morbidity among higher-risk patients. Interestingly, in this study, they used an experience-based randomization scheme, in which they had surgeons within each center who like to do off-pump CABG and those who like to do on-pump CABG, and each surgeon had hundreds of cases under his belt. For the primary endpoint, a composite of death, MI, stroke or TIA, renal failure, acute respiratory distress syndrome, or reoperation for bleeding, the rates were 5.8% of off-pump and 13.3% for on-pump patients (odds ratio, 2.5; P = .01).

I think the conclusions are clear, but not everyone has reached these same conclusions. In ROOBY, the results were different. Although the study was well conducted, it enrolled low-risk patients, in whom avoidance of CPB was unlikely to improve the expected excellent outcomes. And the operations were performed by residents, with supervising attendings who themselves only had to do 20 total career off-pump cases to be eligible. I think this lack of experience is well demonstrated by the 12.5% conversion rate from off-pump cases to on-pump in that trial. ROOBY enrolled the wrong patients and used the wrong surgeons.

In the CORONARY trial, conducted by Dr. Lamy in Canada but enrolling patients from 19 countries outside of Canada, there was no difference in the primary endpoint of death, stroke, MI, and renal failure at 30 days, but there was a decrease in transfusion, reoperation for bleeding, acute kidney injury, or respiratory complications. There wasn\'t a difference in stroke, interestingly, but the surgeons in this trial appropriately converted a hundred patients from on pump to off pump to avoid manipulating a calcified aorta. This was a good, well-conducted trial.

However, the primary outcome in CORONARY differed when assessed according to EuroSCORE. When the EuroSCORE was low, on pump outperformed off pump. When the EuroSCORE was high, off pump outperformed on pump.

These two trials offer important perspective: the ROOBY trial, enrolling low-risk patients, was actually in favor of on-pump CABG. The CORONARY trial, enrolling higher-risk patients, had a slight benefit in favor of off-pump CABG, and this was particularly evident in the Canadian cohort of 830 randomized patients, in which the primary outcome was, in fact, statistically significantly better in the off-pump group at 9.2% vs. 13.7%.

At the end of the day, I think it matters in whom you do off-pump CABG and how well you do it. It may not be for every patient or for every surgeon; off-pump CABG requires a focused and sustained effort to master a new set of physical and psychological skills to accomplish precise and complete revascularization. When we can do this, I think, we offer better outcomes for our patients.

Dr. John Puskas is the chairman of the department of cardiac surgery at Mount Sinai Beth Israel in New York. Dr. Puskas disclosed that he also does both on- and off-pump CABG. He received royalties from coronary surgical instruments marketed by Scanlan, as well.

References

JAMA 2004;291:1841-9

Ann. Thorac. Surg. 2009;88:1142-7

N. Engl. J. Med. 2009;361:1827-37

N. Engl. J. Med. 2010;362:851

N. Engl. J. Med. 2012;366:1489-97

N. Engl. J. Med. 2013;368:1179-88

Ann. Thorac. Surg. 2011;91:1836-42

J. Thorac. Cardiovasc. Surg. 2012;143:625-31

YES

I believe on-pump coronary artery bypass graft (CABG) surgery should be our primary operation, with off-pump CABG reserved only for certain situations.

In talking about these two surgical options, there are basically three main issues of interest: procedural outcomes, the quality of revascularization, and long-term effectiveness.

Procedural outcomes: In the 1990s, there was great excitement for the potential for off-pump CABG. We thought survival would be better, stroke less common, neurocognitive outcomes improved, etc., but after several randomized studies and a number of well-controlled observational studies, we found that, in terms of the important procedural outcomes – death, MI, stroke, and acute renal failure – there were actually no differences between off- and on-pump CABG. We saw this in ROOBY, with low-risk patients and less experienced surgeons; in the Canadian CORONARY trial, with experienced off-pump surgeons; and in the European GOPCABE trial, where the surgeons were very experienced and the patients were high risk.

There are some benefits with off-pump CABG in terms of what I call the "reversible" complications of surgery: fewer transfusions, less postoperative atrial fibrillation, fewer respiratory infections; but I believe these things have to be balanced against some of the negative effects of off-pump surgery in terms of its quality of revascularization and long-term effectiveness.

Probably one of the biggest disappointments we’ve had with off-pump CABG is that, in the trials, we didn’t see any major difference in neurocognitive dysfunction. What we learned is that cardiopulmonary bypass really is not that bad in terms of neurocognitive dysfunction after surgery.

One issue that tends to be forgotten is the risk associated with conversion. In a hemodynamically unstable patient, converting from off-pump to on-pump is associated with higher risks of death, bleeding, renal failure, stroke, respiratory failure, and GI complications. In CORONARY, with experienced surgeons, the conversion rate was almost 7.9%, and in GOPCABE, it was 9.7%. Even with experienced surgeons, conversions do occur, and they have negative consequences.

Quality of revascularization: We know that long-term survival is related to completeness of revascularization. The more ischemic myocardium that is left at risk after CABG, the more likely the patients is to have an MI or die, and this has been very clearly demonstrated in the surgical literature as well as the percutaneous coronary intervention literature. It has been shown multiple times that fewer grafts are done in off-pump patients, compared with on-pump patients. Indeed, in a recent Cochrane meta-analysis of more than 7,000 patients in 57 trials, there were significantly more grafts done in on-pump than off-pump cases.

Also in terms of graft patency, again, multiple studies have shown lower graft patency in off-pump patients, either directly or by means of showing a higher reintervention rate after off-pump as compared with on-pump surgery. In both CORONARY and GOPCABE, the repeat revascularization rate at 30 days was higher for off-pump CABG.

Long-term effectiveness: The long-term results from ROOBY are very sobering: significantly higher 1-year cardiac mortality in the off-pump arm and higher 1-year composite adverse events. Again, in the 2012 Cochrane meta-analysis, with more than 10,000 patients in 75 trials, mortality was significantly higher with off-pump patients, compared with on-pump, with a hazard ratio of 1.24 (95% CI, 1.01-1.53). When the authors of the Cochrane meta-analysis removed what they called the "studies with bias," this signal was even stronger. Also in observational studies, such as one published by Racz et al. in 2004 (J. Am. Coll. Cardiol. 2004; 43: 557-64), the best survival was found to be in patients who had on-pump CABG and the worst in those who had undergone off-pump CABG.

In summary, procedural outcomes with off-pump and on-pump CABG are similar, albeit with lower reversible complications in the off-pump patients, but a greater conversion risk, along with its associated complications. The quality of the revascularization is worse in off-pump patients, the completeness of revascularization is less and re-intervention rates are higher, and the bottom line, of course, it that there is higher long-term mortality after off-pump CABG.

"Should off-pump CABG be abandoned?" As our default procedure, yes. The vast majority of our patients are best served with on-pump revascularization.

Dr. Joseph Sabik is the chairman of the department of thoracic and cardiovascular surgery and the Sheik Hamdam Bin Rashid Al Maktoum Distinguished Chair at the Cleveland Clinic. He disclosed that he performs both off-pump and on-pump CABG.

References

Anesthesiology 2005;102:188-203

N. Engl. J. Med. 2009;361:1827-37

N. Engl. J. Med. 2012;366:1489-97

N. Engl. J. Med. 2013;368:1179-88

Cochrane Database Syst. Rev. 2012; Mar 14. 3: CD007224 [doi:10.1002/14651858.CD007224.pub2])

J. Am. Coll. Cardiol. 2004;43:557-64

NO

Should off pump bypass be abandoned? Absolutely not, but let’s do it well.

The rationale for why off-pump CABG should be the preferred strategy is simple: cardiopulmonary bypass (CPB) entails extracorporeal circulation, aortic cannulation and clamping, global MI, hypothermia, and hemodilution, among other potentially deleterious phenomena. There are morbidities that can be attributed to these entities, and off-pump bypass avoids those effects by mechanically stabilizing each coronary artery target individually, while the rest of the heart beats and supports normal physiologic circulation. There is an important caveat to this, however, and that is if – and perhaps only if – a complete revascularization with precise anastomoses can be accomplished off pump, then the patient will in fact benefit.

At Emory University in Atlanta, we did a prospective, randomized trial on my own patients, which we called SMART (Surgical Management of Arterial Revascularization) trial. What we found was that in 200 unselected, consecutive patients undergoing either off- or on-pump CABG, we had lower myocardial enzyme release, fewer transfusions, more rapid extubation, and a shorter length of stay in hospital with off-pump CABG.

Completeness of revascularization is a very important issue. In SMART, the number of grafts per patient was exactly the same: 3.39 per patient with off-pump CABG and 3.4 with on-pump CABG. We coined the phrase "Index of Completeness of Revascularization," which we defined as the number of grafts we planned to do in examining the arteriogram prior to randomization and surgery divided by the number of grafts we actually did. We found no difference here, meaning we were able to do the operation we planned to do (1.00 vs. 1.01; P = not significant). Moreover, for the lateral wall, which is technically more difficult to reach in a beating heart, the number was similar in the off- and on-pump groups (0.97 vs. 0.98; P = not significant). We also used a similar percentage of arterial grafts in both groups.

CPB was an independent predictor of the need for transfusion by multivariate analysis with an odds ratio of 2.42 (P = .0073) and was associated with a longer length of stay by 1 day (5.1 days for off-pump and 6.1 for on-pump; P = .005 Wilcoxon).

Creatine phosphokinase of muscle band and troponin I release was about half as much in the off-pump group as in the on-pump group (P less than .001 Wilcoxon), and the rates of death, stroke, MI, angina, and reintervention were similar at both 30 days and 1 year, as was graft patency and quality of life. Off-pump CABG costs at 1 year were $1,955 less than on-pump, but this difference was not statistically significant (P = .08).

At 8 years, survival in SMART was still similar between groups (P = .33), as was graft patency in the small number of patients who had CT angiograms. PET scan results similarly showed no significant difference in ischemia between these two groups (P = .62). One patient in each group has had a percutaneous reintervention, and none have had a repeat coronary bypass in 10 years.

To see if these results could be replicated nationally, we turned to the STS database and looked at North American centers that performed more than 100 on-pump CABGs and more than 100 off-pump surgeries. This gave us 42,477 patients (16,245 off pump and 26,232 on pump) at 63 North American centers. We included the 2.2% of off-pump cases that were converted to on-pump cases in the off-pump group.

After risk adjustment for 32 variables, for the outcomes of death, stroke, MI, and major adverse cardiac events, off-pump bypass outperformed on-pump bypass in this huge cohort of patients from around the country. Looking at less-significant outcomes – renal failure, dialysis, sternal infection, reoperation, atrial fibrillation, prolonged ventilation, and length of stay greater than 14 days – all of them favored off-pump bypass.

We then looked at the Emory dataset (14,766 consecutive patients, 48% of whom had off-pump CABG and 52% on-pump) to see which patients benefitted more. For patients in the two lower quartiles of predicted risk, there was no difference in operative mortality. In the higher two risk quartiles, there was a mortality benefit with off-pump CABG, with a risk reduction for operative mortality of about 55% in the highest risk patients (P less than 0.001).

Logistic regression confirmed that there was an interaction between surgery type and predicted risk, and we now know that low-risk patients do not have the survival benefit of avoiding CPB. They do fine with on-pump CABG, but higher risk patients have a benefit from avoiding CPB and the higher the predicted risk, the greater the benefit to the patient.

We went back to the STS database and we looked at whether this applies only at some centers or all centers, some surgeons or all surgeons. We looked at almost a million cases, 210,469 of which were at sites that had a large off-pump CABG volume. With the usual adjustments, off-pump CABG was associated with significant reduction of risk of death, stroke, renal failure, any morbidity or mortality or prolonged length of stay, compared with on-pump bypass. This benefit was even more pronounced after adjustment for surgeon effect. Once again, the greater reduction was enjoyed by those patients who had the highest preoperative risk. In all predicted risk quartiles, off pump bypass reduced risk of death and stroke and that magnitude increased with increasing predicted risk of mortality. This was seen in large-volume centers and low-volume centers.

Similar results were seen in a recent multicenter, randomized, prospective trial by Lemma et al. that assigned 411 patients to either off- or on-pump coronary bypass (J. Thorac. Cardiovasc. Surg. 2012;143:625-31). There was reduced early mortality and morbidity among higher-risk patients. Interestingly, in this study, they used an experience-based randomization scheme, in which they had surgeons within each center who like to do off-pump CABG and those who like to do on-pump CABG, and each surgeon had hundreds of cases under his belt. For the primary endpoint, a composite of death, MI, stroke or TIA, renal failure, acute respiratory distress syndrome, or reoperation for bleeding, the rates were 5.8% of off-pump and 13.3% for on-pump patients (odds ratio, 2.5; P = .01).

I think the conclusions are clear, but not everyone has reached these same conclusions. In ROOBY, the results were different. Although the study was well conducted, it enrolled low-risk patients, in whom avoidance of CPB was unlikely to improve the expected excellent outcomes. And the operations were performed by residents, with supervising attendings who themselves only had to do 20 total career off-pump cases to be eligible. I think this lack of experience is well demonstrated by the 12.5% conversion rate from off-pump cases to on-pump in that trial. ROOBY enrolled the wrong patients and used the wrong surgeons.

In the CORONARY trial, conducted by Dr. Lamy in Canada but enrolling patients from 19 countries outside of Canada, there was no difference in the primary endpoint of death, stroke, MI, and renal failure at 30 days, but there was a decrease in transfusion, reoperation for bleeding, acute kidney injury, or respiratory complications. There wasn\'t a difference in stroke, interestingly, but the surgeons in this trial appropriately converted a hundred patients from on pump to off pump to avoid manipulating a calcified aorta. This was a good, well-conducted trial.

However, the primary outcome in CORONARY differed when assessed according to EuroSCORE. When the EuroSCORE was low, on pump outperformed off pump. When the EuroSCORE was high, off pump outperformed on pump.

These two trials offer important perspective: the ROOBY trial, enrolling low-risk patients, was actually in favor of on-pump CABG. The CORONARY trial, enrolling higher-risk patients, had a slight benefit in favor of off-pump CABG, and this was particularly evident in the Canadian cohort of 830 randomized patients, in which the primary outcome was, in fact, statistically significantly better in the off-pump group at 9.2% vs. 13.7%.

At the end of the day, I think it matters in whom you do off-pump CABG and how well you do it. It may not be for every patient or for every surgeon; off-pump CABG requires a focused and sustained effort to master a new set of physical and psychological skills to accomplish precise and complete revascularization. When we can do this, I think, we offer better outcomes for our patients.

Dr. John Puskas is the chairman of the department of cardiac surgery at Mount Sinai Beth Israel in New York. Dr. Puskas disclosed that he also does both on- and off-pump CABG. He received royalties from coronary surgical instruments marketed by Scanlan, as well.

References

JAMA 2004;291:1841-9

Ann. Thorac. Surg. 2009;88:1142-7

N. Engl. J. Med. 2009;361:1827-37

N. Engl. J. Med. 2010;362:851

N. Engl. J. Med. 2012;366:1489-97

N. Engl. J. Med. 2013;368:1179-88

Ann. Thorac. Surg. 2011;91:1836-42

J. Thorac. Cardiovasc. Surg. 2012;143:625-31

TORONTO – Operative mortality with total aortic arch replacement using a four-branched graft and frozen elephant trunk implantation (Sun’s procedure) was 6.5%, including those whose type A aortic dissection was defined as acute.

Operative mortality was higher in acute versus chronic type A aortic dissection (TAAD) patients undergoing the procedure (8.1% vs. 4.3%; P = .031), as was the incidence of stroke (2.2% vs. 0.6%; P = .046), and respiratory complications (20.8% vs. 8.6%; P less than .001).

However, although the risk of operative mortality in acute patients was 1.95 times higher than for chronic patients, in multivariate analysis, acuteness was not identified as a significant risk factor for operative mortality (odds ratio, 1.67; P = .152).

The factors identified as increasing risk of operative mortality were coexisting cerebrovascular disease; malperfusion of the brain, kidneys, spinal cord, and viscera; concomitant extra-anatomic bypass; and cardiopulmonary bypass time exceeding 180 minutes.

"This study proves the safety of frozen elephant trunk with total arch replacement," said Dr. Wei-Guo Ma of Yale University, New Haven, Conn.

"Operative mortality was not affected by either the acute or chronic phase. Instead it was affected by seven other factors, such as prior CVD [cerebrovascular disease], malperfusion, and longer CPB [cardiopulmonary bypass] time.

"If a patient comes without those risk factors, surgeons can go ahead and perform this emergent frozen elephant trunk for him without fear of imposing greater risk of mortality," he said.

Standard TAAD remains a highly lethal condition, with the greatest surgical risk seen during the acute phase. Although some progress has been made, surgeons continue to debate the optimal surgical approach to TAAD, in particular the extent of distal aortic repair. Some advocate a more limited approach of hemiarch repair only, while others propose that total arch repair offers better outcomes.

Sun’s procedure is performed with right axillary artery cannulation for cardiopulmonary bypass and selective antegrade cerebral perfusion, under moderate hypothermic circulatory arrest at 25° C.

The frozen elephant trunk (Cronus, MicroPort Medical, Shanghai, China) is implanted into the descending aorta, followed by total arch replacement using a four-branched vascular graft, with a special sequence for aortic reconstruction (i.e., proximal descending aorta to left carotid artery to ascending aorta to left subclavian artery to innominate artery). Associated operations, including coronary artery bypass grafting, are performed during the cooling phase, if needed.

In this case series, presented by Dr. Ma at the annual meeting of the American Association for Thoracic Surgery, acuteness was defined as an interval between onset of symptoms and surgery of 14 days or less.

TAAD was diagnosed preoperatively by transthoracic echocardiography or computed tomographic angiography, with the location of the intimal tear confirmed during surgery.

The surgeons retrospectively compared early outcomes between acute and chronic TAAD patients after Sun’s procedure, seeking to identify risk factors for operative mortality in both groups and seeking to determine whether acuteness significantly affects operative mortality after this extensive surgical approach.

Between April 2003 and September 2012, Sun’s procedure was performed on 803 patients with acute or chronic TAAD. Mean age was 46 years and 80% of the cohort was male. A total of 456 were classified as acute TAAD patients, with a mean of 5.5 days lapsing between onset of symptoms to surgery (median, 4.1 days), and 347 were chronic, with 197 days lapsing between onset of symptoms and surgery (median, 38 days).

Clinically apparent malperfusion was common, seen in 12.6% of cases, 12.3% of the acute arm and 9.2% of the chronic arm. Patients with malperfusion had an overall mortality of 19.3% (25% in the acute arm and 9.4% in the chronic arm; P less than .001).

"Visceral malperfusion tended to be the most lethal, with five of seven patients dying," reported Dr. Ma. He also noted the young age of their cohort as compared to other regions of the world: 88.8% of patients were under 60 years of age.

Acute, minus natural selection

The invited discussant on the abstract, Dr. Malakh L. Shrestha took issue with the study’s conclusion that acuteness did not affect operative mortality. Dr. Shrestha is the division manager of valvular and coronary artery surgery at the Hannover (Germany) Medical School.

"As a high volume center, what we’ve learned is that acute and chronic aortic dissection patients are two totally different subsets of patients in terms of clinical presentation and mortality. The greatest danger in the acute patient is in the first few hours after the dissection, with the majority of patients dying without surgical intervention."

At Dr. Shrestha’s center in Germany, a high-volume aortic center, they often see patients within the first few hours of their dissection and they’ve found a significantly higher mortality in these patients, compared with chronic TAAD whether an ascending aortic replacement or a frozen elephant trunk procedure is done.

With a median of 4.1 days lapsing between onset of symptoms and surgery in the Ma et al. study, Dr. Shrestha argued that "although on the basis of classification, you can still say they’re acute, there has been some sort of natural selection. So, I think that means, at least for your conclusions, that you need to clarify the statement that there is no difference between acute and chronic, because these are obviously not the same subset of patients that we see in the Western world."

Dr. Ma agreed that natural selection was indeed at play in their series, in that about 80% of their patients were referrals that were transferred in some cases from hundreds of miles away, with many dying en route or before surgery. He also concurred that had their mean and median number of days in their acute cohort been less, indeed, mortality might have been higher.

Dr. Ma reported having no conflicts of interest. Dr. Shrestha is a consultant for Edwards Lifesciences.

TORONTO – Operative mortality with total aortic arch replacement using a four-branched graft and frozen elephant trunk implantation (Sun’s procedure) was 6.5%, including those whose type A aortic dissection was defined as acute.

Operative mortality was higher in acute versus chronic type A aortic dissection (TAAD) patients undergoing the procedure (8.1% vs. 4.3%; P = .031), as was the incidence of stroke (2.2% vs. 0.6%; P = .046), and respiratory complications (20.8% vs. 8.6%; P less than .001).

However, although the risk of operative mortality in acute patients was 1.95 times higher than for chronic patients, in multivariate analysis, acuteness was not identified as a significant risk factor for operative mortality (odds ratio, 1.67; P = .152).

The factors identified as increasing risk of operative mortality were coexisting cerebrovascular disease; malperfusion of the brain, kidneys, spinal cord, and viscera; concomitant extra-anatomic bypass; and cardiopulmonary bypass time exceeding 180 minutes.

"This study proves the safety of frozen elephant trunk with total arch replacement," said Dr. Wei-Guo Ma of Yale University, New Haven, Conn.

"Operative mortality was not affected by either the acute or chronic phase. Instead it was affected by seven other factors, such as prior CVD [cerebrovascular disease], malperfusion, and longer CPB [cardiopulmonary bypass] time.

"If a patient comes without those risk factors, surgeons can go ahead and perform this emergent frozen elephant trunk for him without fear of imposing greater risk of mortality," he said.

Standard TAAD remains a highly lethal condition, with the greatest surgical risk seen during the acute phase. Although some progress has been made, surgeons continue to debate the optimal surgical approach to TAAD, in particular the extent of distal aortic repair. Some advocate a more limited approach of hemiarch repair only, while others propose that total arch repair offers better outcomes.

Sun’s procedure is performed with right axillary artery cannulation for cardiopulmonary bypass and selective antegrade cerebral perfusion, under moderate hypothermic circulatory arrest at 25° C.

The frozen elephant trunk (Cronus, MicroPort Medical, Shanghai, China) is implanted into the descending aorta, followed by total arch replacement using a four-branched vascular graft, with a special sequence for aortic reconstruction (i.e., proximal descending aorta to left carotid artery to ascending aorta to left subclavian artery to innominate artery). Associated operations, including coronary artery bypass grafting, are performed during the cooling phase, if needed.

In this case series, presented by Dr. Ma at the annual meeting of the American Association for Thoracic Surgery, acuteness was defined as an interval between onset of symptoms and surgery of 14 days or less.

TAAD was diagnosed preoperatively by transthoracic echocardiography or computed tomographic angiography, with the location of the intimal tear confirmed during surgery.

The surgeons retrospectively compared early outcomes between acute and chronic TAAD patients after Sun’s procedure, seeking to identify risk factors for operative mortality in both groups and seeking to determine whether acuteness significantly affects operative mortality after this extensive surgical approach.

Between April 2003 and September 2012, Sun’s procedure was performed on 803 patients with acute or chronic TAAD. Mean age was 46 years and 80% of the cohort was male. A total of 456 were classified as acute TAAD patients, with a mean of 5.5 days lapsing between onset of symptoms to surgery (median, 4.1 days), and 347 were chronic, with 197 days lapsing between onset of symptoms and surgery (median, 38 days).

Clinically apparent malperfusion was common, seen in 12.6% of cases, 12.3% of the acute arm and 9.2% of the chronic arm. Patients with malperfusion had an overall mortality of 19.3% (25% in the acute arm and 9.4% in the chronic arm; P less than .001).

"Visceral malperfusion tended to be the most lethal, with five of seven patients dying," reported Dr. Ma. He also noted the young age of their cohort as compared to other regions of the world: 88.8% of patients were under 60 years of age.

Acute, minus natural selection

The invited discussant on the abstract, Dr. Malakh L. Shrestha took issue with the study’s conclusion that acuteness did not affect operative mortality. Dr. Shrestha is the division manager of valvular and coronary artery surgery at the Hannover (Germany) Medical School.

"As a high volume center, what we’ve learned is that acute and chronic aortic dissection patients are two totally different subsets of patients in terms of clinical presentation and mortality. The greatest danger in the acute patient is in the first few hours after the dissection, with the majority of patients dying without surgical intervention."

At Dr. Shrestha’s center in Germany, a high-volume aortic center, they often see patients within the first few hours of their dissection and they’ve found a significantly higher mortality in these patients, compared with chronic TAAD whether an ascending aortic replacement or a frozen elephant trunk procedure is done.

With a median of 4.1 days lapsing between onset of symptoms and surgery in the Ma et al. study, Dr. Shrestha argued that "although on the basis of classification, you can still say they’re acute, there has been some sort of natural selection. So, I think that means, at least for your conclusions, that you need to clarify the statement that there is no difference between acute and chronic, because these are obviously not the same subset of patients that we see in the Western world."

Dr. Ma agreed that natural selection was indeed at play in their series, in that about 80% of their patients were referrals that were transferred in some cases from hundreds of miles away, with many dying en route or before surgery. He also concurred that had their mean and median number of days in their acute cohort been less, indeed, mortality might have been higher.

Dr. Ma reported having no conflicts of interest. Dr. Shrestha is a consultant for Edwards Lifesciences.

TORONTO – Operative mortality with total aortic arch replacement using a four-branched graft and frozen elephant trunk implantation (Sun’s procedure) was 6.5%, including those whose type A aortic dissection was defined as acute.

Operative mortality was higher in acute versus chronic type A aortic dissection (TAAD) patients undergoing the procedure (8.1% vs. 4.3%; P = .031), as was the incidence of stroke (2.2% vs. 0.6%; P = .046), and respiratory complications (20.8% vs. 8.6%; P less than .001).

However, although the risk of operative mortality in acute patients was 1.95 times higher than for chronic patients, in multivariate analysis, acuteness was not identified as a significant risk factor for operative mortality (odds ratio, 1.67; P = .152).

The factors identified as increasing risk of operative mortality were coexisting cerebrovascular disease; malperfusion of the brain, kidneys, spinal cord, and viscera; concomitant extra-anatomic bypass; and cardiopulmonary bypass time exceeding 180 minutes.

"This study proves the safety of frozen elephant trunk with total arch replacement," said Dr. Wei-Guo Ma of Yale University, New Haven, Conn.

"Operative mortality was not affected by either the acute or chronic phase. Instead it was affected by seven other factors, such as prior CVD [cerebrovascular disease], malperfusion, and longer CPB [cardiopulmonary bypass] time.

"If a patient comes without those risk factors, surgeons can go ahead and perform this emergent frozen elephant trunk for him without fear of imposing greater risk of mortality," he said.

Standard TAAD remains a highly lethal condition, with the greatest surgical risk seen during the acute phase. Although some progress has been made, surgeons continue to debate the optimal surgical approach to TAAD, in particular the extent of distal aortic repair. Some advocate a more limited approach of hemiarch repair only, while others propose that total arch repair offers better outcomes.

Sun’s procedure is performed with right axillary artery cannulation for cardiopulmonary bypass and selective antegrade cerebral perfusion, under moderate hypothermic circulatory arrest at 25° C.

The frozen elephant trunk (Cronus, MicroPort Medical, Shanghai, China) is implanted into the descending aorta, followed by total arch replacement using a four-branched vascular graft, with a special sequence for aortic reconstruction (i.e., proximal descending aorta to left carotid artery to ascending aorta to left subclavian artery to innominate artery). Associated operations, including coronary artery bypass grafting, are performed during the cooling phase, if needed.

In this case series, presented by Dr. Ma at the annual meeting of the American Association for Thoracic Surgery, acuteness was defined as an interval between onset of symptoms and surgery of 14 days or less.

TAAD was diagnosed preoperatively by transthoracic echocardiography or computed tomographic angiography, with the location of the intimal tear confirmed during surgery.

The surgeons retrospectively compared early outcomes between acute and chronic TAAD patients after Sun’s procedure, seeking to identify risk factors for operative mortality in both groups and seeking to determine whether acuteness significantly affects operative mortality after this extensive surgical approach.

Between April 2003 and September 2012, Sun’s procedure was performed on 803 patients with acute or chronic TAAD. Mean age was 46 years and 80% of the cohort was male. A total of 456 were classified as acute TAAD patients, with a mean of 5.5 days lapsing between onset of symptoms to surgery (median, 4.1 days), and 347 were chronic, with 197 days lapsing between onset of symptoms and surgery (median, 38 days).

Clinically apparent malperfusion was common, seen in 12.6% of cases, 12.3% of the acute arm and 9.2% of the chronic arm. Patients with malperfusion had an overall mortality of 19.3% (25% in the acute arm and 9.4% in the chronic arm; P less than .001).

"Visceral malperfusion tended to be the most lethal, with five of seven patients dying," reported Dr. Ma. He also noted the young age of their cohort as compared to other regions of the world: 88.8% of patients were under 60 years of age.

Acute, minus natural selection

The invited discussant on the abstract, Dr. Malakh L. Shrestha took issue with the study’s conclusion that acuteness did not affect operative mortality. Dr. Shrestha is the division manager of valvular and coronary artery surgery at the Hannover (Germany) Medical School.

"As a high volume center, what we’ve learned is that acute and chronic aortic dissection patients are two totally different subsets of patients in terms of clinical presentation and mortality. The greatest danger in the acute patient is in the first few hours after the dissection, with the majority of patients dying without surgical intervention."

At Dr. Shrestha’s center in Germany, a high-volume aortic center, they often see patients within the first few hours of their dissection and they’ve found a significantly higher mortality in these patients, compared with chronic TAAD whether an ascending aortic replacement or a frozen elephant trunk procedure is done.

With a median of 4.1 days lapsing between onset of symptoms and surgery in the Ma et al. study, Dr. Shrestha argued that "although on the basis of classification, you can still say they’re acute, there has been some sort of natural selection. So, I think that means, at least for your conclusions, that you need to clarify the statement that there is no difference between acute and chronic, because these are obviously not the same subset of patients that we see in the Western world."

Dr. Ma agreed that natural selection was indeed at play in their series, in that about 80% of their patients were referrals that were transferred in some cases from hundreds of miles away, with many dying en route or before surgery. He also concurred that had their mean and median number of days in their acute cohort been less, indeed, mortality might have been higher.

Dr. Ma reported having no conflicts of interest. Dr. Shrestha is a consultant for Edwards Lifesciences.

TORONTO – Early postoperative left ventricular dysfunction occurs in about 18% of patients who undergo "early" mitral valve repair for severe degenerative disease and have normal preoperative ejection fractions exceeding 60%.

In two-thirds of these patients, the left ventricular dysfunction is persistent and associated with increased mortality, reported Dr. Rakesh Suri of the Mayo Clinic in Rochester, Minn.

"These results may help redefine what we have held true for the last few decades," Dr. David H. Adams said after hearing the data presented at the annual meeting of the American Association for Thoracic Surgery.

Dr. Adams is program director of the Mitral Valve Repair Center, Mount Sinai Medical Center, New York.

Guidelines from the American College of Cardiology/American Heart Association recommend that, for patients with severe degenerative mitral regurgitation due to leaflet prolapse, mitral valve repair needs to be done before the onset of left ventricular dysfunction.

However, despite this preemptive approach, a proportion of patients experience a profound decrease in left ventricular ejection fraction (LVEF), to less than 50% in the immediate postoperative period.

Dr. Suri and his colleagues studied the incidence, predictors, and short- and long-term consequences of this phenomenon in 1,705 patients with severe degenerative mitral regurgitation but LVEF greater than 60% who underwent mitral valve repair at the Mayo Clinic from Jan. 1, 1993, to June 30, 2012.

Patients were excluded from the study if they were under age 18, had a history of significant coronary artery disease, or were undergoing concomitant cardiac procedures other than Maze, tricuspid valve repair, or closure of a patent foramen ovale, the researchers noted.

After mitral valve repair, 82% of the cohort had normal LVEF (50% or more), and 18% developed early LV dysfunction (less than 50%).

Mean preoperative LVEF was 65.8% in the group that maintained normal ejection fraction post repair and 66.3% in the group that developed LV dysfunction (P less than .001).

In the group of patients in whom an early decline in LV function was noted, the mean fall in LVEF was 36%, compared with a postrepair drop of 11% in patients whose function remained in the normal range (P less than .001).

When the researchers looked at whether or not patients went to surgery with guideline-based class I or IIa triggers for mitral valve repair, those being symptoms of LV dysfunction, atrial fibrillation, or pulmonary hypertension, they found that 37% of patients who did not develop LV dysfunction and 22% of those who did had no class I or IIa triggers.

"In other words, the guidelines were incapable of defining this population prior to the performance of mitral valve repair," Dr. Suri explained.

On multivariate analysis, predictors of early LV dysfunction were higher right ventricular systolic pressure and LV end-systolic dimension (both P less than .001).

Patients with early LV dysfunction continued to have significantly diminished LVEF at less than 5, 5-10, and less than 10 years.

"Examined in terms of the ability to recover a normal ejection fraction with time, we saw that amongst those with no LV dysfunction following mitral valve repair, two-thirds went on to complete recovery," explained Dr. Suri.

"In contrast, among those with early LV dysfunction, only one-third were capable of recovering normal LV function with time. In other words, two-thirds had persistent LV dysfunction despite undergoing ‘early’ mitral valve repair," Dr. Suri said.

Early LVEF of less than 40% was seen to increased late mortality risk by 70%.

According to these data, a "normal" preoperative ejection fraction should not provide false reassurance of the capacity for restoration of LV function late following mitral valve repair, suggesting that surgical intervention prior to the onset of excessive LV dilation or pulmonary hypertension is warranted, Dr. Suri said.

"So much of the evidence base that serves as a foundation for the ACC/AHA guidelines comes from the Mayo experience, and your new data is provocative and will have implications for future guidelines," said Dr. Adams, the invited discussant for the abstract.

Dr. Suri reported having no disclosures related to this presentation.

TORONTO – Early postoperative left ventricular dysfunction occurs in about 18% of patients who undergo "early" mitral valve repair for severe degenerative disease and have normal preoperative ejection fractions exceeding 60%.

In two-thirds of these patients, the left ventricular dysfunction is persistent and associated with increased mortality, reported Dr. Rakesh Suri of the Mayo Clinic in Rochester, Minn.

"These results may help redefine what we have held true for the last few decades," Dr. David H. Adams said after hearing the data presented at the annual meeting of the American Association for Thoracic Surgery.

Dr. Adams is program director of the Mitral Valve Repair Center, Mount Sinai Medical Center, New York.

Guidelines from the American College of Cardiology/American Heart Association recommend that, for patients with severe degenerative mitral regurgitation due to leaflet prolapse, mitral valve repair needs to be done before the onset of left ventricular dysfunction.

However, despite this preemptive approach, a proportion of patients experience a profound decrease in left ventricular ejection fraction (LVEF), to less than 50% in the immediate postoperative period.

Dr. Suri and his colleagues studied the incidence, predictors, and short- and long-term consequences of this phenomenon in 1,705 patients with severe degenerative mitral regurgitation but LVEF greater than 60% who underwent mitral valve repair at the Mayo Clinic from Jan. 1, 1993, to June 30, 2012.

Patients were excluded from the study if they were under age 18, had a history of significant coronary artery disease, or were undergoing concomitant cardiac procedures other than Maze, tricuspid valve repair, or closure of a patent foramen ovale, the researchers noted.

After mitral valve repair, 82% of the cohort had normal LVEF (50% or more), and 18% developed early LV dysfunction (less than 50%).

Mean preoperative LVEF was 65.8% in the group that maintained normal ejection fraction post repair and 66.3% in the group that developed LV dysfunction (P less than .001).

In the group of patients in whom an early decline in LV function was noted, the mean fall in LVEF was 36%, compared with a postrepair drop of 11% in patients whose function remained in the normal range (P less than .001).

When the researchers looked at whether or not patients went to surgery with guideline-based class I or IIa triggers for mitral valve repair, those being symptoms of LV dysfunction, atrial fibrillation, or pulmonary hypertension, they found that 37% of patients who did not develop LV dysfunction and 22% of those who did had no class I or IIa triggers.

"In other words, the guidelines were incapable of defining this population prior to the performance of mitral valve repair," Dr. Suri explained.

On multivariate analysis, predictors of early LV dysfunction were higher right ventricular systolic pressure and LV end-systolic dimension (both P less than .001).

Patients with early LV dysfunction continued to have significantly diminished LVEF at less than 5, 5-10, and less than 10 years.

"Examined in terms of the ability to recover a normal ejection fraction with time, we saw that amongst those with no LV dysfunction following mitral valve repair, two-thirds went on to complete recovery," explained Dr. Suri.

"In contrast, among those with early LV dysfunction, only one-third were capable of recovering normal LV function with time. In other words, two-thirds had persistent LV dysfunction despite undergoing ‘early’ mitral valve repair," Dr. Suri said.

Early LVEF of less than 40% was seen to increased late mortality risk by 70%.

According to these data, a "normal" preoperative ejection fraction should not provide false reassurance of the capacity for restoration of LV function late following mitral valve repair, suggesting that surgical intervention prior to the onset of excessive LV dilation or pulmonary hypertension is warranted, Dr. Suri said.

"So much of the evidence base that serves as a foundation for the ACC/AHA guidelines comes from the Mayo experience, and your new data is provocative and will have implications for future guidelines," said Dr. Adams, the invited discussant for the abstract.

Dr. Suri reported having no disclosures related to this presentation.

TORONTO – Early postoperative left ventricular dysfunction occurs in about 18% of patients who undergo "early" mitral valve repair for severe degenerative disease and have normal preoperative ejection fractions exceeding 60%.

In two-thirds of these patients, the left ventricular dysfunction is persistent and associated with increased mortality, reported Dr. Rakesh Suri of the Mayo Clinic in Rochester, Minn.

"These results may help redefine what we have held true for the last few decades," Dr. David H. Adams said after hearing the data presented at the annual meeting of the American Association for Thoracic Surgery.

Dr. Adams is program director of the Mitral Valve Repair Center, Mount Sinai Medical Center, New York.

Guidelines from the American College of Cardiology/American Heart Association recommend that, for patients with severe degenerative mitral regurgitation due to leaflet prolapse, mitral valve repair needs to be done before the onset of left ventricular dysfunction.

However, despite this preemptive approach, a proportion of patients experience a profound decrease in left ventricular ejection fraction (LVEF), to less than 50% in the immediate postoperative period.

Dr. Suri and his colleagues studied the incidence, predictors, and short- and long-term consequences of this phenomenon in 1,705 patients with severe degenerative mitral regurgitation but LVEF greater than 60% who underwent mitral valve repair at the Mayo Clinic from Jan. 1, 1993, to June 30, 2012.

Patients were excluded from the study if they were under age 18, had a history of significant coronary artery disease, or were undergoing concomitant cardiac procedures other than Maze, tricuspid valve repair, or closure of a patent foramen ovale, the researchers noted.

After mitral valve repair, 82% of the cohort had normal LVEF (50% or more), and 18% developed early LV dysfunction (less than 50%).

Mean preoperative LVEF was 65.8% in the group that maintained normal ejection fraction post repair and 66.3% in the group that developed LV dysfunction (P less than .001).

In the group of patients in whom an early decline in LV function was noted, the mean fall in LVEF was 36%, compared with a postrepair drop of 11% in patients whose function remained in the normal range (P less than .001).

When the researchers looked at whether or not patients went to surgery with guideline-based class I or IIa triggers for mitral valve repair, those being symptoms of LV dysfunction, atrial fibrillation, or pulmonary hypertension, they found that 37% of patients who did not develop LV dysfunction and 22% of those who did had no class I or IIa triggers.

"In other words, the guidelines were incapable of defining this population prior to the performance of mitral valve repair," Dr. Suri explained.

On multivariate analysis, predictors of early LV dysfunction were higher right ventricular systolic pressure and LV end-systolic dimension (both P less than .001).

Patients with early LV dysfunction continued to have significantly diminished LVEF at less than 5, 5-10, and less than 10 years.

"Examined in terms of the ability to recover a normal ejection fraction with time, we saw that amongst those with no LV dysfunction following mitral valve repair, two-thirds went on to complete recovery," explained Dr. Suri.

"In contrast, among those with early LV dysfunction, only one-third were capable of recovering normal LV function with time. In other words, two-thirds had persistent LV dysfunction despite undergoing ‘early’ mitral valve repair," Dr. Suri said.

Early LVEF of less than 40% was seen to increased late mortality risk by 70%.

According to these data, a "normal" preoperative ejection fraction should not provide false reassurance of the capacity for restoration of LV function late following mitral valve repair, suggesting that surgical intervention prior to the onset of excessive LV dilation or pulmonary hypertension is warranted, Dr. Suri said.

"So much of the evidence base that serves as a foundation for the ACC/AHA guidelines comes from the Mayo experience, and your new data is provocative and will have implications for future guidelines," said Dr. Adams, the invited discussant for the abstract.

Dr. Suri reported having no disclosures related to this presentation.

TORONTO – In the United States, fewer than one in five coronary artery bypass graft surgeries are done without cardiopulmonary bypass, according to a large Society of Thoracic Surgeons database study conducted by Dr. Faisal G. Bakaeen of Baylor College of Medicine, the Michael E. DeBakey VA Medical Center, and the Texas Heart Institute, Houston, and colleagues.

As of 2012, 84% of the centers in the United States were doing either 0 or fewer than 50 off-pump cases per year. Among U.S. surgeons, 86% did either no off-pump coronary artery bypass grafts (CABG) or 20 or fewer cases per year.

"We speculate that this decline is because off-pump is technically a more demanding operation than on-pump," said Dr. Bakaeen during his presentation at the annual meeting of the American Association of Thoracic Surgery.

"There are [also] concerns about graft patency and the completeness of revascularization and randomized, controlled trials have shown no mortality or major – and I emphasize major – morbidity benefit."

The invited discussant for the abstract, Dr. Harold L. Lazar, the director of cardiothoracic surgery research at Boston Medical Center, suggested that off-pump CABG numbers "will continue to decline" as overall CABG volume continues to decline, and as higher-volume centers and surgeons opt to do fewer off-pump cases.

"Cardiac surgeons have always been motivated to adopt new techniques that will result in improved outcomes for their patients," said Dr. Lazar. "The continuing decline in the use of OP-CABG [off-pump CABG ] by U.S. surgeons is an indication that OP-CABG is not this type of technique."

Introduced in the early 1990s, off-pump CABG was initially touted as a means of avoiding several of the adverse effects of cardiopulmonary bypass and aortic manipulation. However, the relative benefits of off-pump as compared to on-pump CABG continue to be hotly debated.

Dr. Bakaeen and colleagues used the Society of Thoracic Surgeons Adult Cardiac Surgery Database to examine national trends in the use of off- versus on-pump CABG, looking specifically at volume-specific trends among centers and surgeons.

"This is a megadatabase with a huge number of patients, over 2.1 million patients and over 1,200 centers," said Dr. Bakaeen.

The off-pump and on-pump CABG percentages were calculated in aggregate, by center, and by surgeon for a total of 2,137,841 isolated primary CABG procedures performed between Jan. 1, 1997 and Sept. 30, 2012.

Based on 2007/2008 yearly off-pump volume, the analysis subgroups were "high" [center number greater than 200 cases, surgeon number greater than 100 cases], "intermediate" [center number equals 50-200, surgeon number equals 20-100], and "low" [center number less than 50, surgeon number less than 20].

The utilization of off-pump peaked in 2002 at about 23% but then decreased to 17% in 2012. Most of this decrease was found to be driven by higher-volume centers and higher-volume surgeons doing fewer off-pump cases.

Indeed, for the most recent years studied (2011-2012), 12% of U.S. centers (1,056) and 34% of U.S. surgeons (2,626) did not do any off-pump CABG cases.

Another 72% of centers and 52% of surgeons were low-volume operators (less than 50 cases/year and less than 20 cases/year, respectively.

Only 1% of centers (150) and 1% of surgeons (38) were classified as high-volume off-pump operators.

Of note, while the overall conversion rate – cases that were started as on- or off-pump and switched midprocedure – has remained fairly steady at 6%, the rate of unplanned conversions has risen from a low of about 1% in 2004 to about 3.2% in 2012.

"What was interesting was that there was a direct correlation between off-pump volume and the experience of the surgeon and the conversion rate," reported Dr. Bakaeen.

"So, if you are a higher-volume, experienced off-pump surgeon, you are three times less likely to convert than a low-volume surgeon [P less than .01]."

Dr. Bakaeen concluded that, "off-pump CABG utilization will likely continue to be concentrated in specialized centers and performed by dedicated off-pump surgeons."

Dr. Lazar added: "No operation that can only be performed by a select group of experienced, talented surgeons has ever achieved the test of time. CABG surgery must be performed expertly under all circumstances in all patients and at all hospitals, regardless of cardiac volume. These goals appear to be best achieved with on-pump CABG, which remains the gold standard."

Dr. Bakaeen reported having no financial disclosures.

Dr. Lazar reported that he receives grants and research support from Eli Lilly.

TORONTO – In the United States, fewer than one in five coronary artery bypass graft surgeries are done without cardiopulmonary bypass, according to a large Society of Thoracic Surgeons database study conducted by Dr. Faisal G. Bakaeen of Baylor College of Medicine, the Michael E. DeBakey VA Medical Center, and the Texas Heart Institute, Houston, and colleagues.

As of 2012, 84% of the centers in the United States were doing either 0 or fewer than 50 off-pump cases per year. Among U.S. surgeons, 86% did either no off-pump coronary artery bypass grafts (CABG) or 20 or fewer cases per year.

"We speculate that this decline is because off-pump is technically a more demanding operation than on-pump," said Dr. Bakaeen during his presentation at the annual meeting of the American Association of Thoracic Surgery.

"There are [also] concerns about graft patency and the completeness of revascularization and randomized, controlled trials have shown no mortality or major – and I emphasize major – morbidity benefit."

The invited discussant for the abstract, Dr. Harold L. Lazar, the director of cardiothoracic surgery research at Boston Medical Center, suggested that off-pump CABG numbers "will continue to decline" as overall CABG volume continues to decline, and as higher-volume centers and surgeons opt to do fewer off-pump cases.

"Cardiac surgeons have always been motivated to adopt new techniques that will result in improved outcomes for their patients," said Dr. Lazar. "The continuing decline in the use of OP-CABG [off-pump CABG ] by U.S. surgeons is an indication that OP-CABG is not this type of technique."

Introduced in the early 1990s, off-pump CABG was initially touted as a means of avoiding several of the adverse effects of cardiopulmonary bypass and aortic manipulation. However, the relative benefits of off-pump as compared to on-pump CABG continue to be hotly debated.

Dr. Bakaeen and colleagues used the Society of Thoracic Surgeons Adult Cardiac Surgery Database to examine national trends in the use of off- versus on-pump CABG, looking specifically at volume-specific trends among centers and surgeons.

"This is a megadatabase with a huge number of patients, over 2.1 million patients and over 1,200 centers," said Dr. Bakaeen.

The off-pump and on-pump CABG percentages were calculated in aggregate, by center, and by surgeon for a total of 2,137,841 isolated primary CABG procedures performed between Jan. 1, 1997 and Sept. 30, 2012.

Based on 2007/2008 yearly off-pump volume, the analysis subgroups were "high" [center number greater than 200 cases, surgeon number greater than 100 cases], "intermediate" [center number equals 50-200, surgeon number equals 20-100], and "low" [center number less than 50, surgeon number less than 20].

The utilization of off-pump peaked in 2002 at about 23% but then decreased to 17% in 2012. Most of this decrease was found to be driven by higher-volume centers and higher-volume surgeons doing fewer off-pump cases.

Indeed, for the most recent years studied (2011-2012), 12% of U.S. centers (1,056) and 34% of U.S. surgeons (2,626) did not do any off-pump CABG cases.

Another 72% of centers and 52% of surgeons were low-volume operators (less than 50 cases/year and less than 20 cases/year, respectively.

Only 1% of centers (150) and 1% of surgeons (38) were classified as high-volume off-pump operators.

Of note, while the overall conversion rate – cases that were started as on- or off-pump and switched midprocedure – has remained fairly steady at 6%, the rate of unplanned conversions has risen from a low of about 1% in 2004 to about 3.2% in 2012.

"What was interesting was that there was a direct correlation between off-pump volume and the experience of the surgeon and the conversion rate," reported Dr. Bakaeen.

"So, if you are a higher-volume, experienced off-pump surgeon, you are three times less likely to convert than a low-volume surgeon [P less than .01]."

Dr. Bakaeen concluded that, "off-pump CABG utilization will likely continue to be concentrated in specialized centers and performed by dedicated off-pump surgeons."

Dr. Lazar added: "No operation that can only be performed by a select group of experienced, talented surgeons has ever achieved the test of time. CABG surgery must be performed expertly under all circumstances in all patients and at all hospitals, regardless of cardiac volume. These goals appear to be best achieved with on-pump CABG, which remains the gold standard."

Dr. Bakaeen reported having no financial disclosures.

Dr. Lazar reported that he receives grants and research support from Eli Lilly.

TORONTO – In the United States, fewer than one in five coronary artery bypass graft surgeries are done without cardiopulmonary bypass, according to a large Society of Thoracic Surgeons database study conducted by Dr. Faisal G. Bakaeen of Baylor College of Medicine, the Michael E. DeBakey VA Medical Center, and the Texas Heart Institute, Houston, and colleagues.

As of 2012, 84% of the centers in the United States were doing either 0 or fewer than 50 off-pump cases per year. Among U.S. surgeons, 86% did either no off-pump coronary artery bypass grafts (CABG) or 20 or fewer cases per year.

"We speculate that this decline is because off-pump is technically a more demanding operation than on-pump," said Dr. Bakaeen during his presentation at the annual meeting of the American Association of Thoracic Surgery.

"There are [also] concerns about graft patency and the completeness of revascularization and randomized, controlled trials have shown no mortality or major – and I emphasize major – morbidity benefit."

The invited discussant for the abstract, Dr. Harold L. Lazar, the director of cardiothoracic surgery research at Boston Medical Center, suggested that off-pump CABG numbers "will continue to decline" as overall CABG volume continues to decline, and as higher-volume centers and surgeons opt to do fewer off-pump cases.

"Cardiac surgeons have always been motivated to adopt new techniques that will result in improved outcomes for their patients," said Dr. Lazar. "The continuing decline in the use of OP-CABG [off-pump CABG ] by U.S. surgeons is an indication that OP-CABG is not this type of technique."

Introduced in the early 1990s, off-pump CABG was initially touted as a means of avoiding several of the adverse effects of cardiopulmonary bypass and aortic manipulation. However, the relative benefits of off-pump as compared to on-pump CABG continue to be hotly debated.

Dr. Bakaeen and colleagues used the Society of Thoracic Surgeons Adult Cardiac Surgery Database to examine national trends in the use of off- versus on-pump CABG, looking specifically at volume-specific trends among centers and surgeons.

"This is a megadatabase with a huge number of patients, over 2.1 million patients and over 1,200 centers," said Dr. Bakaeen.

The off-pump and on-pump CABG percentages were calculated in aggregate, by center, and by surgeon for a total of 2,137,841 isolated primary CABG procedures performed between Jan. 1, 1997 and Sept. 30, 2012.

Based on 2007/2008 yearly off-pump volume, the analysis subgroups were "high" [center number greater than 200 cases, surgeon number greater than 100 cases], "intermediate" [center number equals 50-200, surgeon number equals 20-100], and "low" [center number less than 50, surgeon number less than 20].

The utilization of off-pump peaked in 2002 at about 23% but then decreased to 17% in 2012. Most of this decrease was found to be driven by higher-volume centers and higher-volume surgeons doing fewer off-pump cases.

Indeed, for the most recent years studied (2011-2012), 12% of U.S. centers (1,056) and 34% of U.S. surgeons (2,626) did not do any off-pump CABG cases.

Another 72% of centers and 52% of surgeons were low-volume operators (less than 50 cases/year and less than 20 cases/year, respectively.

Only 1% of centers (150) and 1% of surgeons (38) were classified as high-volume off-pump operators.

Of note, while the overall conversion rate – cases that were started as on- or off-pump and switched midprocedure – has remained fairly steady at 6%, the rate of unplanned conversions has risen from a low of about 1% in 2004 to about 3.2% in 2012.

"What was interesting was that there was a direct correlation between off-pump volume and the experience of the surgeon and the conversion rate," reported Dr. Bakaeen.

"So, if you are a higher-volume, experienced off-pump surgeon, you are three times less likely to convert than a low-volume surgeon [P less than .01]."

Dr. Bakaeen concluded that, "off-pump CABG utilization will likely continue to be concentrated in specialized centers and performed by dedicated off-pump surgeons."

Dr. Lazar added: "No operation that can only be performed by a select group of experienced, talented surgeons has ever achieved the test of time. CABG surgery must be performed expertly under all circumstances in all patients and at all hospitals, regardless of cardiac volume. These goals appear to be best achieved with on-pump CABG, which remains the gold standard."

Dr. Bakaeen reported having no financial disclosures.

Dr. Lazar reported that he receives grants and research support from Eli Lilly.

TORONTO – Mitral valve repair rates continue to show great variability, ranging from 0% to 90% for patients with moderate to severe mitral regurgitation, according to data presented by Dr. Damien J. LaPar, a thoracic surgeon at the University of Virginia, Charlottesville.

Surgeons performing more than 20 mitral cases per year were about three times more likely to perform a repair over a replacement compared with surgeons performing fewer than 20 mitral surgeries per year.

"Average annual surgeon volume appears more significantly associated with an increased likelihood for mitral repair than institutional volume," Dr. LaPar reported at the annual meeting of the American Association for Thoracic Surgery. A video of his live presentation is available at the AATS website.

Mitral valve repair appears to be underused despite accumulated data favoring repair over replacement in the treatment of patients with moderate to severe mitral regurgitation. Dr. LaPar and colleagues evaluated the relationship between procedure volume and propensity for mitral repair (over replacement) in a multi-institution cohort of patients.

The Virginia Cardiac Surgery Quality Initiative is a voluntary consortium of 17 collaborating cardiac surgery centers in Virginia that captures about 99% of all the operations performed in the state, with each center contributing their data to the Society of Thoracic Surgeons (STS) Adult Cardiac Surgery Database.

Records for 4,178 patients were evaluated for 2001-2012; 2,516 of these patients underwent isolated mitral valve replacement and 1,662 underwent isolated mitral valve repair. To examine confounding, a propensity-matched cohort was developed with 1,661 patients in each group.

Median annual mitral procedure volume was 54 cases per year for hospitals, ranging from 5 to 128, and 13 cases per year for individual surgeons, ranging from 0 to 58 cases. Mitral valve repair rates also ranged significantly, from 35% to 70% of all mitral valve procedures for hospitals and from 0% to 90% for surgeons.

Mitral valve replacement patients presented with higher STS PROM (5.6% vs. 1.7%, P less than .001), higher age, and a greater number of comorbidities. When the researchers adjusted for STS PROM, both average annual hospital (P = .04) and surgeon (P less than .0001) mitral procedure volumes were associated with probability of mitral repair, with surgeon volume showing more influence in the decision to repair rather than replace the mitral valve.

When the propensity to perform mitral valve repair was plotted against surgeon volume, there was a clear "inflection point" of increased probability for repair over replacement when the average annual surgeon mitral volume (a surrogate for surgeon experience) exceeded 20 operations yearly. This finding was validated in the propensity-matched cohort.

"We did a post hoc analysis and demonstrated that when you categorize volume by our visible threshold of 20 cases per year, for both hospital and surgeon volume in the overall cohort, hospitals and surgeons performing more than 20 cases per year, more strongly performed mitral valve repair," said Dr. LaPar.

Indeed, among surgeons and hospitals performing more than 20 mitral operations annually, repairs were done in 62% of cases, compared to 37% for lower-volume centers. Among surgeons performing more than 20 mitral cases per year, repair rates were 73% compared to 26% for lower-volume mitral operators (both P less than .001).

Similarly significant differences were seen in the propensity-matched cohort, although the effect was more muted (53% vs. 47% for high- and low-volume hospitals and 67% vs. 39% for high- and low-volume surgeons; P less than .001 for both).

"In the upcoming era of percutaneous mitral valve repair technology, we believe that surgeon volume and expertise should act as a gatekeeper and should dictate not only access to this technology but the role of surgeons and cardiologists in this," concluded Dr. LaPar.

"This will be an excellent contribution to the literature further defining the relationship between surgeon volume and hospital center volume in mitral valve surgical outcomes and choice of operation," said the invited discussant, Dr. David A Fullerton of the University of Colorado at Denver, Aurora.

Dr. Daniel Drake, head of the Michigan Society of Thoracic and Cardiovascular Surgeons Mitral Initiative, added that in his state they have started to see a greater number of referrals – based on an assessment of case complexity – from less experienced surgeons to more experienced surgeons. Dr. LaPar noted that he hadn’t yet seen this widely in Virginia.

Dr. LaPar and Dr. Fullerton reported no disclosures.

TORONTO – Mitral valve repair rates continue to show great variability, ranging from 0% to 90% for patients with moderate to severe mitral regurgitation, according to data presented by Dr. Damien J. LaPar, a thoracic surgeon at the University of Virginia, Charlottesville.

Surgeons performing more than 20 mitral cases per year were about three times more likely to perform a repair over a replacement compared with surgeons performing fewer than 20 mitral surgeries per year.

"Average annual surgeon volume appears more significantly associated with an increased likelihood for mitral repair than institutional volume," Dr. LaPar reported at the annual meeting of the American Association for Thoracic Surgery. A video of his live presentation is available at the AATS website.

Mitral valve repair appears to be underused despite accumulated data favoring repair over replacement in the treatment of patients with moderate to severe mitral regurgitation. Dr. LaPar and colleagues evaluated the relationship between procedure volume and propensity for mitral repair (over replacement) in a multi-institution cohort of patients.

The Virginia Cardiac Surgery Quality Initiative is a voluntary consortium of 17 collaborating cardiac surgery centers in Virginia that captures about 99% of all the operations performed in the state, with each center contributing their data to the Society of Thoracic Surgeons (STS) Adult Cardiac Surgery Database.

Records for 4,178 patients were evaluated for 2001-2012; 2,516 of these patients underwent isolated mitral valve replacement and 1,662 underwent isolated mitral valve repair. To examine confounding, a propensity-matched cohort was developed with 1,661 patients in each group.

Median annual mitral procedure volume was 54 cases per year for hospitals, ranging from 5 to 128, and 13 cases per year for individual surgeons, ranging from 0 to 58 cases. Mitral valve repair rates also ranged significantly, from 35% to 70% of all mitral valve procedures for hospitals and from 0% to 90% for surgeons.

Mitral valve replacement patients presented with higher STS PROM (5.6% vs. 1.7%, P less than .001), higher age, and a greater number of comorbidities. When the researchers adjusted for STS PROM, both average annual hospital (P = .04) and surgeon (P less than .0001) mitral procedure volumes were associated with probability of mitral repair, with surgeon volume showing more influence in the decision to repair rather than replace the mitral valve.

When the propensity to perform mitral valve repair was plotted against surgeon volume, there was a clear "inflection point" of increased probability for repair over replacement when the average annual surgeon mitral volume (a surrogate for surgeon experience) exceeded 20 operations yearly. This finding was validated in the propensity-matched cohort.

"We did a post hoc analysis and demonstrated that when you categorize volume by our visible threshold of 20 cases per year, for both hospital and surgeon volume in the overall cohort, hospitals and surgeons performing more than 20 cases per year, more strongly performed mitral valve repair," said Dr. LaPar.

Indeed, among surgeons and hospitals performing more than 20 mitral operations annually, repairs were done in 62% of cases, compared to 37% for lower-volume centers. Among surgeons performing more than 20 mitral cases per year, repair rates were 73% compared to 26% for lower-volume mitral operators (both P less than .001).

Similarly significant differences were seen in the propensity-matched cohort, although the effect was more muted (53% vs. 47% for high- and low-volume hospitals and 67% vs. 39% for high- and low-volume surgeons; P less than .001 for both).

"In the upcoming era of percutaneous mitral valve repair technology, we believe that surgeon volume and expertise should act as a gatekeeper and should dictate not only access to this technology but the role of surgeons and cardiologists in this," concluded Dr. LaPar.

"This will be an excellent contribution to the literature further defining the relationship between surgeon volume and hospital center volume in mitral valve surgical outcomes and choice of operation," said the invited discussant, Dr. David A Fullerton of the University of Colorado at Denver, Aurora.

Dr. Daniel Drake, head of the Michigan Society of Thoracic and Cardiovascular Surgeons Mitral Initiative, added that in his state they have started to see a greater number of referrals – based on an assessment of case complexity – from less experienced surgeons to more experienced surgeons. Dr. LaPar noted that he hadn’t yet seen this widely in Virginia.

Dr. LaPar and Dr. Fullerton reported no disclosures.

TORONTO – Mitral valve repair rates continue to show great variability, ranging from 0% to 90% for patients with moderate to severe mitral regurgitation, according to data presented by Dr. Damien J. LaPar, a thoracic surgeon at the University of Virginia, Charlottesville.

Surgeons performing more than 20 mitral cases per year were about three times more likely to perform a repair over a replacement compared with surgeons performing fewer than 20 mitral surgeries per year.

"Average annual surgeon volume appears more significantly associated with an increased likelihood for mitral repair than institutional volume," Dr. LaPar reported at the annual meeting of the American Association for Thoracic Surgery. A video of his live presentation is available at the AATS website.

Mitral valve repair appears to be underused despite accumulated data favoring repair over replacement in the treatment of patients with moderate to severe mitral regurgitation. Dr. LaPar and colleagues evaluated the relationship between procedure volume and propensity for mitral repair (over replacement) in a multi-institution cohort of patients.

The Virginia Cardiac Surgery Quality Initiative is a voluntary consortium of 17 collaborating cardiac surgery centers in Virginia that captures about 99% of all the operations performed in the state, with each center contributing their data to the Society of Thoracic Surgeons (STS) Adult Cardiac Surgery Database.

Records for 4,178 patients were evaluated for 2001-2012; 2,516 of these patients underwent isolated mitral valve replacement and 1,662 underwent isolated mitral valve repair. To examine confounding, a propensity-matched cohort was developed with 1,661 patients in each group.

Median annual mitral procedure volume was 54 cases per year for hospitals, ranging from 5 to 128, and 13 cases per year for individual surgeons, ranging from 0 to 58 cases. Mitral valve repair rates also ranged significantly, from 35% to 70% of all mitral valve procedures for hospitals and from 0% to 90% for surgeons.

Mitral valve replacement patients presented with higher STS PROM (5.6% vs. 1.7%, P less than .001), higher age, and a greater number of comorbidities. When the researchers adjusted for STS PROM, both average annual hospital (P = .04) and surgeon (P less than .0001) mitral procedure volumes were associated with probability of mitral repair, with surgeon volume showing more influence in the decision to repair rather than replace the mitral valve.

When the propensity to perform mitral valve repair was plotted against surgeon volume, there was a clear "inflection point" of increased probability for repair over replacement when the average annual surgeon mitral volume (a surrogate for surgeon experience) exceeded 20 operations yearly. This finding was validated in the propensity-matched cohort.

"We did a post hoc analysis and demonstrated that when you categorize volume by our visible threshold of 20 cases per year, for both hospital and surgeon volume in the overall cohort, hospitals and surgeons performing more than 20 cases per year, more strongly performed mitral valve repair," said Dr. LaPar.

Indeed, among surgeons and hospitals performing more than 20 mitral operations annually, repairs were done in 62% of cases, compared to 37% for lower-volume centers. Among surgeons performing more than 20 mitral cases per year, repair rates were 73% compared to 26% for lower-volume mitral operators (both P less than .001).

Similarly significant differences were seen in the propensity-matched cohort, although the effect was more muted (53% vs. 47% for high- and low-volume hospitals and 67% vs. 39% for high- and low-volume surgeons; P less than .001 for both).

"In the upcoming era of percutaneous mitral valve repair technology, we believe that surgeon volume and expertise should act as a gatekeeper and should dictate not only access to this technology but the role of surgeons and cardiologists in this," concluded Dr. LaPar.

"This will be an excellent contribution to the literature further defining the relationship between surgeon volume and hospital center volume in mitral valve surgical outcomes and choice of operation," said the invited discussant, Dr. David A Fullerton of the University of Colorado at Denver, Aurora.

Dr. Daniel Drake, head of the Michigan Society of Thoracic and Cardiovascular Surgeons Mitral Initiative, added that in his state they have started to see a greater number of referrals – based on an assessment of case complexity – from less experienced surgeons to more experienced surgeons. Dr. LaPar noted that he hadn’t yet seen this widely in Virginia.

Dr. LaPar and Dr. Fullerton reported no disclosures.

TORONTO – In a multicenter European study, 30-day mortality and 1-year mortality after implantation of the stentless Freedom Solo aortic bioprosthetic valve were 1.4% and 4.4%, respectively. Patients in the study experienced "remarkable" functional status improvement at 1 year, reported principal investigator Dr. Markus Thalmann at the annual meeting of the American Association for Thoracic Surgery.

"Our trial showed excellent results in terms of morbidity and mortality and low rates of valve-related adverse events in a 12-month follow-up period," said Dr. Thalmann during his late-breaking clinical trials presentation. "It also demonstrated good hemodynamics leading to a remarkable functional status improvement."

The Sorin Freedom Solo aortic bioprosthesis is made of two layers of bovine pericardium, with no synthetic material added. The valve is implanted with a single running suture line technique in a strict supra-annular position and has no contact with the native annulus. The bioprosthesis is not approved in the United States.

Dr. Thalmann, of Krankenhaus Hietzing, Vienna, noted the importance of performing a careful decalcification of the annulus during implantation. "You should do it as properly as you’d do it when implanting a stented valve, even if you don’t put your stitches through the annulus," he said.

In response to a question, he said that the trial was requested by the Food and Drug Administration to provide more information on the single-line suture technique used to implant the valve.

The researchers conducted a prospective, nonrandomized, multicenter trial at 18 clinical centers in eight European countries. All patients with an indication for prosthetic aortic valve replacement were included, except those with a preexisting valve prosthesis in the mitral, pulmonary, or tricuspid positions. Patients needing double or triple valve replacement were also excluded, as were those with active endocarditis and congenital bicuspid valves.

A total of 616 patients received the valve. Patients had a mean age of 74.5 years, 45.9% were female, and the mean logistic EuroSCORE was 10.1%. Concomitant cardiac procedures, including coronary artery bypass grafting, were performed in 43.2% of patients.

Early (30-day) mortality was 1.4%, rising to 4.4% at 1 year. Valve-related mortality at 30 days and 1 year was 0.3% and 1.1%, respectively.

Overall morbidity was low. At 30 days, 4.5% of patients required reintervention for bleeding, 0.3% for perivalvular leakage. No structural valve dysfunction or valve thrombosis was noted at 30 days, with one case of each seen at 1 year (0.2% and 0.2%).

Preoperatively, 49.3% of patients were in New York Heart Association class III or IV heart failure. At 1 year, 97.0% were in NYHA class I or II heart failure.

"We found good hemodynamics after 1 year," said Dr. Thalmann. The overall mean gradient was 7.2 mm Hg, and the effective orifice area was 1.5 cm².

Patients will be followed for up to 5 years.

The Freedom Solo valve is currently being tested in an investigational device exemption (IDE) study in the United States. The Sorin Solo Smart valve, the evolution of the Freedom Solo valve, received a European CE mark approval in November 2013.

Dr. Thalmann is a consultant for the Sorin Group, which funded the study.

TORONTO – In a multicenter European study, 30-day mortality and 1-year mortality after implantation of the stentless Freedom Solo aortic bioprosthetic valve were 1.4% and 4.4%, respectively. Patients in the study experienced "remarkable" functional status improvement at 1 year, reported principal investigator Dr. Markus Thalmann at the annual meeting of the American Association for Thoracic Surgery.

"Our trial showed excellent results in terms of morbidity and mortality and low rates of valve-related adverse events in a 12-month follow-up period," said Dr. Thalmann during his late-breaking clinical trials presentation. "It also demonstrated good hemodynamics leading to a remarkable functional status improvement."

The Sorin Freedom Solo aortic bioprosthesis is made of two layers of bovine pericardium, with no synthetic material added. The valve is implanted with a single running suture line technique in a strict supra-annular position and has no contact with the native annulus. The bioprosthesis is not approved in the United States.

Dr. Thalmann, of Krankenhaus Hietzing, Vienna, noted the importance of performing a careful decalcification of the annulus during implantation. "You should do it as properly as you’d do it when implanting a stented valve, even if you don’t put your stitches through the annulus," he said.

In response to a question, he said that the trial was requested by the Food and Drug Administration to provide more information on the single-line suture technique used to implant the valve.

The researchers conducted a prospective, nonrandomized, multicenter trial at 18 clinical centers in eight European countries. All patients with an indication for prosthetic aortic valve replacement were included, except those with a preexisting valve prosthesis in the mitral, pulmonary, or tricuspid positions. Patients needing double or triple valve replacement were also excluded, as were those with active endocarditis and congenital bicuspid valves.

A total of 616 patients received the valve. Patients had a mean age of 74.5 years, 45.9% were female, and the mean logistic EuroSCORE was 10.1%. Concomitant cardiac procedures, including coronary artery bypass grafting, were performed in 43.2% of patients.

Early (30-day) mortality was 1.4%, rising to 4.4% at 1 year. Valve-related mortality at 30 days and 1 year was 0.3% and 1.1%, respectively.

Overall morbidity was low. At 30 days, 4.5% of patients required reintervention for bleeding, 0.3% for perivalvular leakage. No structural valve dysfunction or valve thrombosis was noted at 30 days, with one case of each seen at 1 year (0.2% and 0.2%).

Preoperatively, 49.3% of patients were in New York Heart Association class III or IV heart failure. At 1 year, 97.0% were in NYHA class I or II heart failure.

"We found good hemodynamics after 1 year," said Dr. Thalmann. The overall mean gradient was 7.2 mm Hg, and the effective orifice area was 1.5 cm².

Patients will be followed for up to 5 years.

The Freedom Solo valve is currently being tested in an investigational device exemption (IDE) study in the United States. The Sorin Solo Smart valve, the evolution of the Freedom Solo valve, received a European CE mark approval in November 2013.

Dr. Thalmann is a consultant for the Sorin Group, which funded the study.

TORONTO – In a multicenter European study, 30-day mortality and 1-year mortality after implantation of the stentless Freedom Solo aortic bioprosthetic valve were 1.4% and 4.4%, respectively. Patients in the study experienced "remarkable" functional status improvement at 1 year, reported principal investigator Dr. Markus Thalmann at the annual meeting of the American Association for Thoracic Surgery.

"Our trial showed excellent results in terms of morbidity and mortality and low rates of valve-related adverse events in a 12-month follow-up period," said Dr. Thalmann during his late-breaking clinical trials presentation. "It also demonstrated good hemodynamics leading to a remarkable functional status improvement."

The Sorin Freedom Solo aortic bioprosthesis is made of two layers of bovine pericardium, with no synthetic material added. The valve is implanted with a single running suture line technique in a strict supra-annular position and has no contact with the native annulus. The bioprosthesis is not approved in the United States.

Dr. Thalmann, of Krankenhaus Hietzing, Vienna, noted the importance of performing a careful decalcification of the annulus during implantation. "You should do it as properly as you’d do it when implanting a stented valve, even if you don’t put your stitches through the annulus," he said.

In response to a question, he said that the trial was requested by the Food and Drug Administration to provide more information on the single-line suture technique used to implant the valve.

The researchers conducted a prospective, nonrandomized, multicenter trial at 18 clinical centers in eight European countries. All patients with an indication for prosthetic aortic valve replacement were included, except those with a preexisting valve prosthesis in the mitral, pulmonary, or tricuspid positions. Patients needing double or triple valve replacement were also excluded, as were those with active endocarditis and congenital bicuspid valves.

A total of 616 patients received the valve. Patients had a mean age of 74.5 years, 45.9% were female, and the mean logistic EuroSCORE was 10.1%. Concomitant cardiac procedures, including coronary artery bypass grafting, were performed in 43.2% of patients.

Early (30-day) mortality was 1.4%, rising to 4.4% at 1 year. Valve-related mortality at 30 days and 1 year was 0.3% and 1.1%, respectively.

Overall morbidity was low. At 30 days, 4.5% of patients required reintervention for bleeding, 0.3% for perivalvular leakage. No structural valve dysfunction or valve thrombosis was noted at 30 days, with one case of each seen at 1 year (0.2% and 0.2%).

Preoperatively, 49.3% of patients were in New York Heart Association class III or IV heart failure. At 1 year, 97.0% were in NYHA class I or II heart failure.

"We found good hemodynamics after 1 year," said Dr. Thalmann. The overall mean gradient was 7.2 mm Hg, and the effective orifice area was 1.5 cm².

Patients will be followed for up to 5 years.

The Freedom Solo valve is currently being tested in an investigational device exemption (IDE) study in the United States. The Sorin Solo Smart valve, the evolution of the Freedom Solo valve, received a European CE mark approval in November 2013.

Dr. Thalmann is a consultant for the Sorin Group, which funded the study.

TORONTO – Device positioning may help explain significant increases in pump thrombosis after left ventricular assist device implantation, according to a single-center study presented at the 2014 annual meeting of the American Association for Thoracic Surgery.

Dr. Jay Bhama, associate director of lung and heart transplantation at the University of Pittsburgh, found that more device-positioning issues coincided with more occurrences of pump thrombosis (PT). The adequacy of anticoagulation, major adverse events, and medical noncompliance were not found to be contributing factors, Dr. Bhama said.

His investigation joins recently published data indicating that left ventricular assist device (LVAD) thrombosis nearly quadrupled in less than 2 years in a multicenter study.

The purported mechanisms of PT in patients supported with the HeartMate II LVAD are thought to be multifactorial, but possibly related to design modifications, expansion of use to the destination therapy indication, nonuniform surgical implant technique, and nonuniform anticoagulation strategies across centers and over time.

"Starting in 2010, we started to notice a rapid and sudden increase in the rate of pump thrombosis, which has increased steadily over the last 3 years," said Dr. Bhama, who reported that PT occurred in 10 of 62 patients (16%) treated at the University of Pittsburgh Medical Center, with an overall event rate of 0.281 per patient-year.

In response to the increase, the group at the medical center investigated how potential contributing factors may have changed over time. They retrospectively assessed all primary LVAD implants in patients who survived hospitalization (62 of 74 total implants) between 2004 and 2012, grouping patients according to the era of implant: from June 2004 to December 2009 (era 1; n = 24) and from January 2010 (when FDA approval was given to expand use to destination therapy) to December 2012 (era 2; n = 38).

None of those who died during the index hospitalization experienced PT, Dr. Bhama noted.

PT was defined as either visualized thrombus within the pump at device exchange or significant hemolysis in the setting of heart failure symptoms or pump malfunction.

The actuarial freedom from PT at 24 months was significantly lower in era 2 than in era 1 (57% vs. 100%; P = .016).

Effective anticoagulation (percent of all international normalized ratio [INR] measurements greater than 1.8) was more reliably achieved in era 2 than in era 1 (50% vs. 34%; P less than .001).

To assess device positioning, the researchers looked at the angle of the inflow cannula, defining malposition as either less than the 5th or greater than the 95th percentile of the median of all the inflow cannula angles. Regarding the outflow cannula, they looked at patients who had bend-relief disconnects, either partial or complete, and those who had radiographic evidence of outflow graft malposition or kink.

Device positioning issues were significantly more prevalent during era 2 than during era 1 (29% vs. 4%). Most of this difference was driven by inflow cannula positioning problems, Dr. Bhama noted.

When the patients with concerns related to device positioning were excluded, the freedom from PT at 24 months no longer differed significantly between groups (P = .094).

The groups were demographically similar except for age, which was higher in the era 2 group (57 years, vs. 50 years for era 1; P = .037). More patients in the era 2 group received an LVAD for destination therapy, although this difference actually wasn’t significant (61% vs. 38%; P = .066).

The groups were also similar with regard to early major adverse events (right ventricular failure, bleeding, infection, and stroke) and medical noncompliance.

In the earlier multicenter study, Dr. Randall C. Starling, of the Cleveland Clinic, and his colleagues reported an abrupt increase in LVAD thrombosis: Between March 2011 and Jan. 1, 2013, the occurrence of PT at 3 months after implantation increased from 2.2% to 8.4% (N. Engl. J. Med. 2014;370:33-40).

"Dissecting the root cause of this problem is an extremely difficult task," said Dr. Nader Moazami, the invited discussant for Dr. Bhama’s presentation and the second author on the Starling paper. Dr. Moazami is surgical director of the Kaufman Center for Heart Failure at the Cleveland Clinic.

"While recent advances in LVAD technology with continuous-flow pumps have saved the lives of thousands of dying patients, issues related to adverse events and the associated morbidity and mortality are of immense importance, specifically as we consider the relevance of this technology to the more ambulatory heart failure patients," said Dr. Moazami, commenting on the study.

However, he suggested that the real cause of the recent increase in PT has not yet been discovered, and questioned the validity of assessing inflow cannula angulation based on a chest x-ray. "This to my knowledge has never been validated and was a concern in about half of the patients in the pump thrombosis group," Dr. Moazami said. Patients with "a demonstrable mechanical reason for pump thrombosis" were excluded from the Starling team’s analysis, he added.

In response, Dr. Bhama cited a study by Dr. Abeel Mangi, a cardiac surgeon at Yale University, New Haven, Conn., which found that greater angulation of the HeartMate II inflow cannula, along with the depth of the pump pocket, correlated with the development of PT (Ann. Thorac. Surg. 2013;96:1259-65).

"These aren’t just angles that are slightly off here and there," noted Dr. Bhama. "These are splayed very widely, situations I think where we all would say this is something we should be concerned about."

Dr. Bhama reported no relevant disclosures.

TORONTO – Device positioning may help explain significant increases in pump thrombosis after left ventricular assist device implantation, according to a single-center study presented at the 2014 annual meeting of the American Association for Thoracic Surgery.

Dr. Jay Bhama, associate director of lung and heart transplantation at the University of Pittsburgh, found that more device-positioning issues coincided with more occurrences of pump thrombosis (PT). The adequacy of anticoagulation, major adverse events, and medical noncompliance were not found to be contributing factors, Dr. Bhama said.

His investigation joins recently published data indicating that left ventricular assist device (LVAD) thrombosis nearly quadrupled in less than 2 years in a multicenter study.

The purported mechanisms of PT in patients supported with the HeartMate II LVAD are thought to be multifactorial, but possibly related to design modifications, expansion of use to the destination therapy indication, nonuniform surgical implant technique, and nonuniform anticoagulation strategies across centers and over time.

"Starting in 2010, we started to notice a rapid and sudden increase in the rate of pump thrombosis, which has increased steadily over the last 3 years," said Dr. Bhama, who reported that PT occurred in 10 of 62 patients (16%) treated at the University of Pittsburgh Medical Center, with an overall event rate of 0.281 per patient-year.

In response to the increase, the group at the medical center investigated how potential contributing factors may have changed over time. They retrospectively assessed all primary LVAD implants in patients who survived hospitalization (62 of 74 total implants) between 2004 and 2012, grouping patients according to the era of implant: from June 2004 to December 2009 (era 1; n = 24) and from January 2010 (when FDA approval was given to expand use to destination therapy) to December 2012 (era 2; n = 38).

None of those who died during the index hospitalization experienced PT, Dr. Bhama noted.

PT was defined as either visualized thrombus within the pump at device exchange or significant hemolysis in the setting of heart failure symptoms or pump malfunction.

The actuarial freedom from PT at 24 months was significantly lower in era 2 than in era 1 (57% vs. 100%; P = .016).

Effective anticoagulation (percent of all international normalized ratio [INR] measurements greater than 1.8) was more reliably achieved in era 2 than in era 1 (50% vs. 34%; P less than .001).

To assess device positioning, the researchers looked at the angle of the inflow cannula, defining malposition as either less than the 5th or greater than the 95th percentile of the median of all the inflow cannula angles. Regarding the outflow cannula, they looked at patients who had bend-relief disconnects, either partial or complete, and those who had radiographic evidence of outflow graft malposition or kink.

Device positioning issues were significantly more prevalent during era 2 than during era 1 (29% vs. 4%). Most of this difference was driven by inflow cannula positioning problems, Dr. Bhama noted.

When the patients with concerns related to device positioning were excluded, the freedom from PT at 24 months no longer differed significantly between groups (P = .094).

The groups were demographically similar except for age, which was higher in the era 2 group (57 years, vs. 50 years for era 1; P = .037). More patients in the era 2 group received an LVAD for destination therapy, although this difference actually wasn’t significant (61% vs. 38%; P = .066).

The groups were also similar with regard to early major adverse events (right ventricular failure, bleeding, infection, and stroke) and medical noncompliance.

In the earlier multicenter study, Dr. Randall C. Starling, of the Cleveland Clinic, and his colleagues reported an abrupt increase in LVAD thrombosis: Between March 2011 and Jan. 1, 2013, the occurrence of PT at 3 months after implantation increased from 2.2% to 8.4% (N. Engl. J. Med. 2014;370:33-40).

"Dissecting the root cause of this problem is an extremely difficult task," said Dr. Nader Moazami, the invited discussant for Dr. Bhama’s presentation and the second author on the Starling paper. Dr. Moazami is surgical director of the Kaufman Center for Heart Failure at the Cleveland Clinic.

"While recent advances in LVAD technology with continuous-flow pumps have saved the lives of thousands of dying patients, issues related to adverse events and the associated morbidity and mortality are of immense importance, specifically as we consider the relevance of this technology to the more ambulatory heart failure patients," said Dr. Moazami, commenting on the study.

However, he suggested that the real cause of the recent increase in PT has not yet been discovered, and questioned the validity of assessing inflow cannula angulation based on a chest x-ray. "This to my knowledge has never been validated and was a concern in about half of the patients in the pump thrombosis group," Dr. Moazami said. Patients with "a demonstrable mechanical reason for pump thrombosis" were excluded from the Starling team’s analysis, he added.

In response, Dr. Bhama cited a study by Dr. Abeel Mangi, a cardiac surgeon at Yale University, New Haven, Conn., which found that greater angulation of the HeartMate II inflow cannula, along with the depth of the pump pocket, correlated with the development of PT (Ann. Thorac. Surg. 2013;96:1259-65).

"These aren’t just angles that are slightly off here and there," noted Dr. Bhama. "These are splayed very widely, situations I think where we all would say this is something we should be concerned about."

Dr. Bhama reported no relevant disclosures.

TORONTO – Device positioning may help explain significant increases in pump thrombosis after left ventricular assist device implantation, according to a single-center study presented at the 2014 annual meeting of the American Association for Thoracic Surgery.

Dr. Jay Bhama, associate director of lung and heart transplantation at the University of Pittsburgh, found that more device-positioning issues coincided with more occurrences of pump thrombosis (PT). The adequacy of anticoagulation, major adverse events, and medical noncompliance were not found to be contributing factors, Dr. Bhama said.

His investigation joins recently published data indicating that left ventricular assist device (LVAD) thrombosis nearly quadrupled in less than 2 years in a multicenter study.

The purported mechanisms of PT in patients supported with the HeartMate II LVAD are thought to be multifactorial, but possibly related to design modifications, expansion of use to the destination therapy indication, nonuniform surgical implant technique, and nonuniform anticoagulation strategies across centers and over time.

"Starting in 2010, we started to notice a rapid and sudden increase in the rate of pump thrombosis, which has increased steadily over the last 3 years," said Dr. Bhama, who reported that PT occurred in 10 of 62 patients (16%) treated at the University of Pittsburgh Medical Center, with an overall event rate of 0.281 per patient-year.

In response to the increase, the group at the medical center investigated how potential contributing factors may have changed over time. They retrospectively assessed all primary LVAD implants in patients who survived hospitalization (62 of 74 total implants) between 2004 and 2012, grouping patients according to the era of implant: from June 2004 to December 2009 (era 1; n = 24) and from January 2010 (when FDA approval was given to expand use to destination therapy) to December 2012 (era 2; n = 38).

None of those who died during the index hospitalization experienced PT, Dr. Bhama noted.

PT was defined as either visualized thrombus within the pump at device exchange or significant hemolysis in the setting of heart failure symptoms or pump malfunction.

The actuarial freedom from PT at 24 months was significantly lower in era 2 than in era 1 (57% vs. 100%; P = .016).

Effective anticoagulation (percent of all international normalized ratio [INR] measurements greater than 1.8) was more reliably achieved in era 2 than in era 1 (50% vs. 34%; P less than .001).

To assess device positioning, the researchers looked at the angle of the inflow cannula, defining malposition as either less than the 5th or greater than the 95th percentile of the median of all the inflow cannula angles. Regarding the outflow cannula, they looked at patients who had bend-relief disconnects, either partial or complete, and those who had radiographic evidence of outflow graft malposition or kink.

Device positioning issues were significantly more prevalent during era 2 than during era 1 (29% vs. 4%). Most of this difference was driven by inflow cannula positioning problems, Dr. Bhama noted.

When the patients with concerns related to device positioning were excluded, the freedom from PT at 24 months no longer differed significantly between groups (P = .094).

The groups were demographically similar except for age, which was higher in the era 2 group (57 years, vs. 50 years for era 1; P = .037). More patients in the era 2 group received an LVAD for destination therapy, although this difference actually wasn’t significant (61% vs. 38%; P = .066).

The groups were also similar with regard to early major adverse events (right ventricular failure, bleeding, infection, and stroke) and medical noncompliance.

In the earlier multicenter study, Dr. Randall C. Starling, of the Cleveland Clinic, and his colleagues reported an abrupt increase in LVAD thrombosis: Between March 2011 and Jan. 1, 2013, the occurrence of PT at 3 months after implantation increased from 2.2% to 8.4% (N. Engl. J. Med. 2014;370:33-40).

"Dissecting the root cause of this problem is an extremely difficult task," said Dr. Nader Moazami, the invited discussant for Dr. Bhama’s presentation and the second author on the Starling paper. Dr. Moazami is surgical director of the Kaufman Center for Heart Failure at the Cleveland Clinic.

"While recent advances in LVAD technology with continuous-flow pumps have saved the lives of thousands of dying patients, issues related to adverse events and the associated morbidity and mortality are of immense importance, specifically as we consider the relevance of this technology to the more ambulatory heart failure patients," said Dr. Moazami, commenting on the study.

However, he suggested that the real cause of the recent increase in PT has not yet been discovered, and questioned the validity of assessing inflow cannula angulation based on a chest x-ray. "This to my knowledge has never been validated and was a concern in about half of the patients in the pump thrombosis group," Dr. Moazami said. Patients with "a demonstrable mechanical reason for pump thrombosis" were excluded from the Starling team’s analysis, he added.

In response, Dr. Bhama cited a study by Dr. Abeel Mangi, a cardiac surgeon at Yale University, New Haven, Conn., which found that greater angulation of the HeartMate II inflow cannula, along with the depth of the pump pocket, correlated with the development of PT (Ann. Thorac. Surg. 2013;96:1259-65).

"These aren’t just angles that are slightly off here and there," noted Dr. Bhama. "These are splayed very widely, situations I think where we all would say this is something we should be concerned about."

Dr. Bhama reported no relevant disclosures.

TORONTO – Transcatheter mitral valve-in-valve/valve-in-ring implantation is an effective option in most patients with degenerative mitral valves after surgical intervention, according to Dr. Danny Dvir.

In the highest-risk patients (STS scores greater than 20%), however, mortality after this percutaneous technique approached 50% at 1 year, Dr. Dvir reported at the American Association for Thoracic Surgery annual meeting.

"Most of these procedures were clinically effective, with 1-year results that are comparable to native aortic valve transcatheter implantation," said Dr. Dvir of St. Paul’s Hospital, Vancouver, B.C.

"However, we saw safety and efficacy concerns that included relatively high in-hospital mortality, device malposition, sporadic cases with elevated LVOT [left ventricular outflow tract] gradient, and elevated postprocedural gradients in procedures performed inside small surgical valves."

Dr. Joseph E. Bavaria, professor of surgery and director of the thoracic aortic surgery program at the University of Pennsylvania Health System, Philadelphia, the scheduled discussant of the abstract, asked, referring to the STS score greater than 20% group: "Is this really a cohort C or futile situation, where [the intervention] is probably not better than medical management?"

Transcatheter VIV/VIR

The majority of prosthetic heart valves are tissue valves that tend to degenerate and eventually fail over time. Surgical replacement of these valves is associated with significant risks.

Transcatheter valve-in-valve/valve-in-ring (VIV/VIR) implantation within a failed bioprosthesis performed in the mitral position has been reported in only small case series, with the safety and efficacy of the technique being largely unknown. The Global Valve-in-Valve Registry, with 765 patients from 73 centers worldwide, was designed to track the efficacy and safety of this nonsurgical redo in either the aortic or mitral valve position. The registry included 190 patients from 23 centers who underwent percutaneous mitral valve procedures (VIV in 157 patients and VIR in 33).

The mechanism of failure was regurgitation in 37%, stenosis in 25%, and a combination of the two in 38%. Patients were a median of 9 years past their last cardiac surgery and were deemed at high risk, with a mean STS score of 14.4. The mean age was 73.6 years, and 65.2% were female. The median length of hospital stay was 8 days.

A SAPIEN or SAPIEN XT device was used in the majority of cases (93.7%), mostly deployed via transapical access (84.7%).

During the procedure, initial device malpositioning occurred in 5.3% of cases, with a second device implanted in 4.3%. Postimplantation valvuloplasty was utilized in 8%.

"We saw a high rate of malpositioning," Dr. Dvir said. "In some of the cases, this led to a decision to leave the malpositioned device in the left atrium and implant a second device."

The incidence of all-cause death at 30 days was 8.9%, with cardiovascular death seen in 6.8% and major stroke in 2.2%. Importantly, 85.8% of patients were in NYHA function class I or II at 30 days, Dr. Dvir said.

"We were very happy to see this," he commented. "If you survive the valve-in-valve or valve-in-ring procedure, you will most likely have a good functional class.

Overall, the Kaplan-Meier mortality rate was 22.3% at 1 year. When stratified according to STS score, however, mortality in the group of patients with an STS score greater than 20% was 45.6%, falling to 23.2% for an STS score of 10%-20% and 12.9% for an STS score less than 10%. Predictors of 1-year mortality included STS score and renal failure.

"In these patients with STS greater than 20%, there is really a big problem. We need to understand which patients should not undergo a procedure, and maybe should be treated with an alternative approach," Dr. Dvir said. He noted that 28% of cases in the registry were in this highest-risk category.

"An 8.9% mortality at 1 year is not so bad in a group with a mean STS score of 14.1," noted Dr. Bavaria. "[But] this is not really a benign procedure as the length of stay was over 8 days."

Surgical valve sizing gone wrong?

After the VIV/VIR procedure, the mean mitral valve area was 2.1 ± 0.7 cm², with a mean residual gradient of 6.2 mm Hg. Significant mitral regurgitation was noted in 4.2% of patients, and a left ventricular outflow tract mean gradient greater than 20 mm Hg was noted in only 2.1% of cases.

"We saw a trend for elevated gradients especially when we were treating small valves with a valve-in-valve approach," Dr. Dvir said.

Indeed, in the patients with smaller surgical valve label size, one-third had postprocedural mean gradients greater than 10 mm Hg. The rates of mean gradient greater than 10 mm Hg dropped to 7.4% and 5.3% with progressively larger surgical valve label sizes.

"I am very worried about the cardiac surgery and interventional cardiology decision-making process, as over 60% of valve-in-ring cases were 26-mm and 28-mm rings and over 56% of valve-in-valve cases were less than or equal to 27-mm prosthetic valves," said Dr. Bavaria. "There will obviously be significant mitral gradients in these cases, as this study showed. Is this simply a lack of knowledge in the operators, should these small valve-in-valve cases be done, or is this a limit of this technology?"

"I think this issue of residual gradients will haunt valve in valve for many years to come," said Dr. Dvir. "However, we know from the aortic arena, that even if you have a high residual gradient, the results at 1 year are not different than the other groups. So, it doesn’t affect 1-year outcomes, although I predict that it will affect the durability of the device and the long-term outcome."

TORONTO – Transcatheter mitral valve-in-valve/valve-in-ring implantation is an effective option in most patients with degenerative mitral valves after surgical intervention, according to Dr. Danny Dvir.

In the highest-risk patients (STS scores greater than 20%), however, mortality after this percutaneous technique approached 50% at 1 year, Dr. Dvir reported at the American Association for Thoracic Surgery annual meeting.

"Most of these procedures were clinically effective, with 1-year results that are comparable to native aortic valve transcatheter implantation," said Dr. Dvir of St. Paul’s Hospital, Vancouver, B.C.

"However, we saw safety and efficacy concerns that included relatively high in-hospital mortality, device malposition, sporadic cases with elevated LVOT [left ventricular outflow tract] gradient, and elevated postprocedural gradients in procedures performed inside small surgical valves."

Dr. Joseph E. Bavaria, professor of surgery and director of the thoracic aortic surgery program at the University of Pennsylvania Health System, Philadelphia, the scheduled discussant of the abstract, asked, referring to the STS score greater than 20% group: "Is this really a cohort C or futile situation, where [the intervention] is probably not better than medical management?"

Transcatheter VIV/VIR

The majority of prosthetic heart valves are tissue valves that tend to degenerate and eventually fail over time. Surgical replacement of these valves is associated with significant risks.

Transcatheter valve-in-valve/valve-in-ring (VIV/VIR) implantation within a failed bioprosthesis performed in the mitral position has been reported in only small case series, with the safety and efficacy of the technique being largely unknown. The Global Valve-in-Valve Registry, with 765 patients from 73 centers worldwide, was designed to track the efficacy and safety of this nonsurgical redo in either the aortic or mitral valve position. The registry included 190 patients from 23 centers who underwent percutaneous mitral valve procedures (VIV in 157 patients and VIR in 33).

The mechanism of failure was regurgitation in 37%, stenosis in 25%, and a combination of the two in 38%. Patients were a median of 9 years past their last cardiac surgery and were deemed at high risk, with a mean STS score of 14.4. The mean age was 73.6 years, and 65.2% were female. The median length of hospital stay was 8 days.

A SAPIEN or SAPIEN XT device was used in the majority of cases (93.7%), mostly deployed via transapical access (84.7%).

During the procedure, initial device malpositioning occurred in 5.3% of cases, with a second device implanted in 4.3%. Postimplantation valvuloplasty was utilized in 8%.

"We saw a high rate of malpositioning," Dr. Dvir said. "In some of the cases, this led to a decision to leave the malpositioned device in the left atrium and implant a second device."

The incidence of all-cause death at 30 days was 8.9%, with cardiovascular death seen in 6.8% and major stroke in 2.2%. Importantly, 85.8% of patients were in NYHA function class I or II at 30 days, Dr. Dvir said.

"We were very happy to see this," he commented. "If you survive the valve-in-valve or valve-in-ring procedure, you will most likely have a good functional class.

Overall, the Kaplan-Meier mortality rate was 22.3% at 1 year. When stratified according to STS score, however, mortality in the group of patients with an STS score greater than 20% was 45.6%, falling to 23.2% for an STS score of 10%-20% and 12.9% for an STS score less than 10%. Predictors of 1-year mortality included STS score and renal failure.

"In these patients with STS greater than 20%, there is really a big problem. We need to understand which patients should not undergo a procedure, and maybe should be treated with an alternative approach," Dr. Dvir said. He noted that 28% of cases in the registry were in this highest-risk category.

"An 8.9% mortality at 1 year is not so bad in a group with a mean STS score of 14.1," noted Dr. Bavaria. "[But] this is not really a benign procedure as the length of stay was over 8 days."

Surgical valve sizing gone wrong?

After the VIV/VIR procedure, the mean mitral valve area was 2.1 ± 0.7 cm², with a mean residual gradient of 6.2 mm Hg. Significant mitral regurgitation was noted in 4.2% of patients, and a left ventricular outflow tract mean gradient greater than 20 mm Hg was noted in only 2.1% of cases.

"We saw a trend for elevated gradients especially when we were treating small valves with a valve-in-valve approach," Dr. Dvir said.

Indeed, in the patients with smaller surgical valve label size, one-third had postprocedural mean gradients greater than 10 mm Hg. The rates of mean gradient greater than 10 mm Hg dropped to 7.4% and 5.3% with progressively larger surgical valve label sizes.

"I am very worried about the cardiac surgery and interventional cardiology decision-making process, as over 60% of valve-in-ring cases were 26-mm and 28-mm rings and over 56% of valve-in-valve cases were less than or equal to 27-mm prosthetic valves," said Dr. Bavaria. "There will obviously be significant mitral gradients in these cases, as this study showed. Is this simply a lack of knowledge in the operators, should these small valve-in-valve cases be done, or is this a limit of this technology?"

"I think this issue of residual gradients will haunt valve in valve for many years to come," said Dr. Dvir. "However, we know from the aortic arena, that even if you have a high residual gradient, the results at 1 year are not different than the other groups. So, it doesn’t affect 1-year outcomes, although I predict that it will affect the durability of the device and the long-term outcome."

TORONTO – Transcatheter mitral valve-in-valve/valve-in-ring implantation is an effective option in most patients with degenerative mitral valves after surgical intervention, according to Dr. Danny Dvir.

In the highest-risk patients (STS scores greater than 20%), however, mortality after this percutaneous technique approached 50% at 1 year, Dr. Dvir reported at the American Association for Thoracic Surgery annual meeting.

"Most of these procedures were clinically effective, with 1-year results that are comparable to native aortic valve transcatheter implantation," said Dr. Dvir of St. Paul’s Hospital, Vancouver, B.C.

"However, we saw safety and efficacy concerns that included relatively high in-hospital mortality, device malposition, sporadic cases with elevated LVOT [left ventricular outflow tract] gradient, and elevated postprocedural gradients in procedures performed inside small surgical valves."

Dr. Joseph E. Bavaria, professor of surgery and director of the thoracic aortic surgery program at the University of Pennsylvania Health System, Philadelphia, the scheduled discussant of the abstract, asked, referring to the STS score greater than 20% group: "Is this really a cohort C or futile situation, where [the intervention] is probably not better than medical management?"

Transcatheter VIV/VIR

The majority of prosthetic heart valves are tissue valves that tend to degenerate and eventually fail over time. Surgical replacement of these valves is associated with significant risks.

Transcatheter valve-in-valve/valve-in-ring (VIV/VIR) implantation within a failed bioprosthesis performed in the mitral position has been reported in only small case series, with the safety and efficacy of the technique being largely unknown. The Global Valve-in-Valve Registry, with 765 patients from 73 centers worldwide, was designed to track the efficacy and safety of this nonsurgical redo in either the aortic or mitral valve position. The registry included 190 patients from 23 centers who underwent percutaneous mitral valve procedures (VIV in 157 patients and VIR in 33).

The mechanism of failure was regurgitation in 37%, stenosis in 25%, and a combination of the two in 38%. Patients were a median of 9 years past their last cardiac surgery and were deemed at high risk, with a mean STS score of 14.4. The mean age was 73.6 years, and 65.2% were female. The median length of hospital stay was 8 days.

A SAPIEN or SAPIEN XT device was used in the majority of cases (93.7%), mostly deployed via transapical access (84.7%).

During the procedure, initial device malpositioning occurred in 5.3% of cases, with a second device implanted in 4.3%. Postimplantation valvuloplasty was utilized in 8%.

"We saw a high rate of malpositioning," Dr. Dvir said. "In some of the cases, this led to a decision to leave the malpositioned device in the left atrium and implant a second device."

The incidence of all-cause death at 30 days was 8.9%, with cardiovascular death seen in 6.8% and major stroke in 2.2%. Importantly, 85.8% of patients were in NYHA function class I or II at 30 days, Dr. Dvir said.

"We were very happy to see this," he commented. "If you survive the valve-in-valve or valve-in-ring procedure, you will most likely have a good functional class.

Overall, the Kaplan-Meier mortality rate was 22.3% at 1 year. When stratified according to STS score, however, mortality in the group of patients with an STS score greater than 20% was 45.6%, falling to 23.2% for an STS score of 10%-20% and 12.9% for an STS score less than 10%. Predictors of 1-year mortality included STS score and renal failure.

"In these patients with STS greater than 20%, there is really a big problem. We need to understand which patients should not undergo a procedure, and maybe should be treated with an alternative approach," Dr. Dvir said. He noted that 28% of cases in the registry were in this highest-risk category.

"An 8.9% mortality at 1 year is not so bad in a group with a mean STS score of 14.1," noted Dr. Bavaria. "[But] this is not really a benign procedure as the length of stay was over 8 days."

Surgical valve sizing gone wrong?

After the VIV/VIR procedure, the mean mitral valve area was 2.1 ± 0.7 cm², with a mean residual gradient of 6.2 mm Hg. Significant mitral regurgitation was noted in 4.2% of patients, and a left ventricular outflow tract mean gradient greater than 20 mm Hg was noted in only 2.1% of cases.

"We saw a trend for elevated gradients especially when we were treating small valves with a valve-in-valve approach," Dr. Dvir said.

Indeed, in the patients with smaller surgical valve label size, one-third had postprocedural mean gradients greater than 10 mm Hg. The rates of mean gradient greater than 10 mm Hg dropped to 7.4% and 5.3% with progressively larger surgical valve label sizes.

"I am very worried about the cardiac surgery and interventional cardiology decision-making process, as over 60% of valve-in-ring cases were 26-mm and 28-mm rings and over 56% of valve-in-valve cases were less than or equal to 27-mm prosthetic valves," said Dr. Bavaria. "There will obviously be significant mitral gradients in these cases, as this study showed. Is this simply a lack of knowledge in the operators, should these small valve-in-valve cases be done, or is this a limit of this technology?"

"I think this issue of residual gradients will haunt valve in valve for many years to come," said Dr. Dvir. "However, we know from the aortic arena, that even if you have a high residual gradient, the results at 1 year are not different than the other groups. So, it doesn’t affect 1-year outcomes, although I predict that it will affect the durability of the device and the long-term outcome."

TORONTO – Mitral valve repair rates continue to show great variability, ranging from zero to 90% for patients with moderate to severe mitral regurgitation, according to data presented by Dr. Damien J. LaPar, a thoracic surgeon at the University of Virginia, Charlottesville.

Surgeons performing more than 20 mitral cases per year were about three times more likely to perform a repair over a replacement compared with surgeons performing fewer than 20 mitral surgeries per year.

"Average annual surgeon volume appears more significantly associated with an increased likelihood for mitral repair than institutional volume," Dr. LaPar reported at the annual meeting of the American Association for Thoracic Surgery.

Mitral valve repair appears to be underused despite accumulated data favoring repair over replacement in the treatment of patients with moderate to severe mitral regurgitation. Dr. LaPar and colleagues evaluated the relationship between procedure volume and propensity for mitral repair (over replacement) in a multi-institution, regional cohort of patients.

The Virginia Cardiac Surgery Quality Initiative is a voluntary consortium of 17 collaborating cardiac surgery centers in Virginia that captures about 99% of all the operations performed in the state, with each center contributing their data to the Society of Thoracic Surgeons (STS) Adult Cardiac Surgery Database.

Records for 4,178 patients were evaluated from 2001-2012; 2,516 of these patients underwent isolated mitral valve replacement and 1,662 underwent isolated mitral valve repair. To deal with issues of confounding, a propensity matched cohort was developed including 1,661 patients in each group.

Median annual mitral procedure volume was 54 cases per year for hospitals, ranging from 5 to 128, and 13 cases per year for individual surgeons, ranging from zero to 58 cases. Mitral valve repair rates also ranged significantly, from 35% to 70% of all mitral valve procedures for hospitals and from zero to 90% for surgeons.

As expected, mitral valve replacement patients presented with higher STS PROM (5.6% vs. 1.7%, P less than .001), higher age, and a greater number of comorbidities.

When the researchers adjusted for STS PROM, both average annual hospital (P = .04) and surgeon (P less than .0001) mitral procedure volume were associated with probability of mitral repair, with surgeon volume showing more influence in the decision to repair rather than replace the mitral valve.

When the propensity to perform mitral valve repair was plotted against surgeon volume, the researchers saw a clear "inflection point" of increased probability for repair over replacement when the average annual surgeon mitral volume (used as a surrogate for surgeon experience) exceeded 20 operations per year. This finding was validated in the propensity matched cohort.

"We did a post hoc analysis and demonstrated that when you categorize volume by our visible threshold of 20 cases per year, for both hospital and surgeon volume in the overall cohort, hospitals and surgeons performing more than 20 cases per year, more strongly performed mitral valve repair," reported Dr. LaPar.

Indeed, among surgeons and hospitals performing more than 20 mitral operations annually, repairs were done in 62% of cases, compared to 37% for lower-volume centers. Among surgeons performing more than 20 mitral cases per year, repair rates were 73% compared to 26% for lower-volume mitral operators (both P less than .001).

Similarly significant differences were seen in the propensity matched cohort, although the effect was more muted (53% vs. 47% for high- and low-volume hospitals and 67% vs. 39% for high- and low-volume surgeons; P less than .001 for both).

"In the upcoming era of percutaneous mitral valve repair technology, we believe that surgeon volume and expertise should act as a gatekeeper and should dictate not only access to this technology but the role of surgeons and cardiologists in this," concluded Dr. LaPar.

"This will be an excellent contribution to the literature further defining the relationship between surgeon volume and hospital center volume in mitral valve surgical outcomes and choice of operation," said the invited discussant, Dr. David A Fullerton, professor of surgery and cardiothoracic surgery at the University of Colorado at Denver, Aurora.

Dr. Daniel Drake, the current head of the Michigan Society of Thoracic and Cardiovascular Surgeons Mitral Initiative, added that in his state they have started to see a greater number of referrals – based on an assessment of case complexity – from less experienced surgeons to more experienced surgeons.

Dr. LaPar agreed that this would be a good solution, but noted that he hadn’t yet seen this happening widely in Virginia.

Dr. LaPar and Dr. Fullerton reported having no financial disclosures.

TORONTO – Mitral valve repair rates continue to show great variability, ranging from zero to 90% for patients with moderate to severe mitral regurgitation, according to data presented by Dr. Damien J. LaPar, a thoracic surgeon at the University of Virginia, Charlottesville.

Surgeons performing more than 20 mitral cases per year were about three times more likely to perform a repair over a replacement compared with surgeons performing fewer than 20 mitral surgeries per year.

"Average annual surgeon volume appears more significantly associated with an increased likelihood for mitral repair than institutional volume," Dr. LaPar reported at the annual meeting of the American Association for Thoracic Surgery.

Mitral valve repair appears to be underused despite accumulated data favoring repair over replacement in the treatment of patients with moderate to severe mitral regurgitation. Dr. LaPar and colleagues evaluated the relationship between procedure volume and propensity for mitral repair (over replacement) in a multi-institution, regional cohort of patients.

The Virginia Cardiac Surgery Quality Initiative is a voluntary consortium of 17 collaborating cardiac surgery centers in Virginia that captures about 99% of all the operations performed in the state, with each center contributing their data to the Society of Thoracic Surgeons (STS) Adult Cardiac Surgery Database.

Records for 4,178 patients were evaluated from 2001-2012; 2,516 of these patients underwent isolated mitral valve replacement and 1,662 underwent isolated mitral valve repair. To deal with issues of confounding, a propensity matched cohort was developed including 1,661 patients in each group.

Median annual mitral procedure volume was 54 cases per year for hospitals, ranging from 5 to 128, and 13 cases per year for individual surgeons, ranging from zero to 58 cases. Mitral valve repair rates also ranged significantly, from 35% to 70% of all mitral valve procedures for hospitals and from zero to 90% for surgeons.

As expected, mitral valve replacement patients presented with higher STS PROM (5.6% vs. 1.7%, P less than .001), higher age, and a greater number of comorbidities.

When the researchers adjusted for STS PROM, both average annual hospital (P = .04) and surgeon (P less than .0001) mitral procedure volume were associated with probability of mitral repair, with surgeon volume showing more influence in the decision to repair rather than replace the mitral valve.

When the propensity to perform mitral valve repair was plotted against surgeon volume, the researchers saw a clear "inflection point" of increased probability for repair over replacement when the average annual surgeon mitral volume (used as a surrogate for surgeon experience) exceeded 20 operations per year. This finding was validated in the propensity matched cohort.

"We did a post hoc analysis and demonstrated that when you categorize volume by our visible threshold of 20 cases per year, for both hospital and surgeon volume in the overall cohort, hospitals and surgeons performing more than 20 cases per year, more strongly performed mitral valve repair," reported Dr. LaPar.

Indeed, among surgeons and hospitals performing more than 20 mitral operations annually, repairs were done in 62% of cases, compared to 37% for lower-volume centers. Among surgeons performing more than 20 mitral cases per year, repair rates were 73% compared to 26% for lower-volume mitral operators (both P less than .001).

Similarly significant differences were seen in the propensity matched cohort, although the effect was more muted (53% vs. 47% for high- and low-volume hospitals and 67% vs. 39% for high- and low-volume surgeons; P less than .001 for both).

"In the upcoming era of percutaneous mitral valve repair technology, we believe that surgeon volume and expertise should act as a gatekeeper and should dictate not only access to this technology but the role of surgeons and cardiologists in this," concluded Dr. LaPar.

"This will be an excellent contribution to the literature further defining the relationship between surgeon volume and hospital center volume in mitral valve surgical outcomes and choice of operation," said the invited discussant, Dr. David A Fullerton, professor of surgery and cardiothoracic surgery at the University of Colorado at Denver, Aurora.

Dr. Daniel Drake, the current head of the Michigan Society of Thoracic and Cardiovascular Surgeons Mitral Initiative, added that in his state they have started to see a greater number of referrals – based on an assessment of case complexity – from less experienced surgeons to more experienced surgeons.

Dr. LaPar agreed that this would be a good solution, but noted that he hadn’t yet seen this happening widely in Virginia.

Dr. LaPar and Dr. Fullerton reported having no financial disclosures.

TORONTO – Mitral valve repair rates continue to show great variability, ranging from zero to 90% for patients with moderate to severe mitral regurgitation, according to data presented by Dr. Damien J. LaPar, a thoracic surgeon at the University of Virginia, Charlottesville.

Surgeons performing more than 20 mitral cases per year were about three times more likely to perform a repair over a replacement compared with surgeons performing fewer than 20 mitral surgeries per year.

"Average annual surgeon volume appears more significantly associated with an increased likelihood for mitral repair than institutional volume," Dr. LaPar reported at the annual meeting of the American Association for Thoracic Surgery.

Mitral valve repair appears to be underused despite accumulated data favoring repair over replacement in the treatment of patients with moderate to severe mitral regurgitation. Dr. LaPar and colleagues evaluated the relationship between procedure volume and propensity for mitral repair (over replacement) in a multi-institution, regional cohort of patients.

The Virginia Cardiac Surgery Quality Initiative is a voluntary consortium of 17 collaborating cardiac surgery centers in Virginia that captures about 99% of all the operations performed in the state, with each center contributing their data to the Society of Thoracic Surgeons (STS) Adult Cardiac Surgery Database.

Records for 4,178 patients were evaluated from 2001-2012; 2,516 of these patients underwent isolated mitral valve replacement and 1,662 underwent isolated mitral valve repair. To deal with issues of confounding, a propensity matched cohort was developed including 1,661 patients in each group.

Median annual mitral procedure volume was 54 cases per year for hospitals, ranging from 5 to 128, and 13 cases per year for individual surgeons, ranging from zero to 58 cases. Mitral valve repair rates also ranged significantly, from 35% to 70% of all mitral valve procedures for hospitals and from zero to 90% for surgeons.

As expected, mitral valve replacement patients presented with higher STS PROM (5.6% vs. 1.7%, P less than .001), higher age, and a greater number of comorbidities.

When the researchers adjusted for STS PROM, both average annual hospital (P = .04) and surgeon (P less than .0001) mitral procedure volume were associated with probability of mitral repair, with surgeon volume showing more influence in the decision to repair rather than replace the mitral valve.

When the propensity to perform mitral valve repair was plotted against surgeon volume, the researchers saw a clear "inflection point" of increased probability for repair over replacement when the average annual surgeon mitral volume (used as a surrogate for surgeon experience) exceeded 20 operations per year. This finding was validated in the propensity matched cohort.

"We did a post hoc analysis and demonstrated that when you categorize volume by our visible threshold of 20 cases per year, for both hospital and surgeon volume in the overall cohort, hospitals and surgeons performing more than 20 cases per year, more strongly performed mitral valve repair," reported Dr. LaPar.

Indeed, among surgeons and hospitals performing more than 20 mitral operations annually, repairs were done in 62% of cases, compared to 37% for lower-volume centers. Among surgeons performing more than 20 mitral cases per year, repair rates were 73% compared to 26% for lower-volume mitral operators (both P less than .001).

Similarly significant differences were seen in the propensity matched cohort, although the effect was more muted (53% vs. 47% for high- and low-volume hospitals and 67% vs. 39% for high- and low-volume surgeons; P less than .001 for both).

"In the upcoming era of percutaneous mitral valve repair technology, we believe that surgeon volume and expertise should act as a gatekeeper and should dictate not only access to this technology but the role of surgeons and cardiologists in this," concluded Dr. LaPar.

"This will be an excellent contribution to the literature further defining the relationship between surgeon volume and hospital center volume in mitral valve surgical outcomes and choice of operation," said the invited discussant, Dr. David A Fullerton, professor of surgery and cardiothoracic surgery at the University of Colorado at Denver, Aurora.

Dr. Daniel Drake, the current head of the Michigan Society of Thoracic and Cardiovascular Surgeons Mitral Initiative, added that in his state they have started to see a greater number of referrals – based on an assessment of case complexity – from less experienced surgeons to more experienced surgeons.

Dr. LaPar agreed that this would be a good solution, but noted that he hadn’t yet seen this happening widely in Virginia.

Dr. LaPar and Dr. Fullerton reported having no financial disclosures.

TORONTO – Routine EEG monitoring after surgery with cardiopulmonary bypass in neonates revealed a seizure incidence of 8% in a recent study. In most cases (85%), seizure activity was detectable only on EEG and would not have been identified or treated without EEG monitoring, reported Dr. Maryam Y. Naim, a critical care pediatrician at the Children’s Hospital of Philadelphia, during the American Association for Thoracic Surgery Annual Meeting.

Of concern, status epilepticus was noted in 62% of neonates with seizures, and mortality was higher in babies with seizures versus those without (38% vs. 3%; P less than .01).

"Postoperative seizures are associated with worse neurological outcomes," said Dr. Naim. In addition to being a biomarker of underlying brain injury, there is some evidence that the seizures themselves may cause secondary brain injury.

The American Clinical Neurophysiology Society (ACNS) recommends routine EEG monitoring following infant cardiac surgery. The CHOP group implemented this recommendation and performed a quality improvement study to determine the incidence of seizures in neonates following surgery with cardiopulmonary bypass (CBP).

A total of 161 neonates had 48-hours of EEG monitoring initiated within 6 hours of cardiac surgery with CPB. The median gestational age of the cohort was 39 weeks, 16% were premature, and 13% had identified genetic defects. The median age at the time of surgery was 5 days. Deep hypothermic circulatory arrest was used in 48% of surgeries (median time, 48 minutes), 16% had open chest with delayed sternal closure, and 9% had a cardiac arrest.

Seizures were detected in 13 (8%), with a median onset of 20 hours after return to the cardiac ICU (CICU) from surgery. Seizures were subclinical, or EEG only, in 11 patients (85%), electroclinical in the other 2 (15%), and status epilepticus was seen in 8 (62%).

When seizures occurred, the CICU team was notified by the EEG technologist, neurology consult was obtained, and the patient was treated with antiseizure medications. As well, abnormal vital signs or movements suggestive of seizure activity were noted at the bedside; although such events were recorded in 32 patients (22%), none had EEG correlates consistent with seizure activity.

"Neonates with all types of heart disease had seizures ... " reported Dr. Naim. " ... with a highest percentage occurring in those with single ventricles and arch obstruction."

Neuroimaging studies were reviewed by a neurologist to determine any association between injury and seizure location. The most commonly detected lesion was periventricular leukomalacia, and four patients had seizures arising from one of their injury sites.

Although neonates with and without seizures had similar CICU lengths of stay, mortality was higher in those with seizures (38% vs. 3%; P less than .01). No predictors of seizures were identified on multivariable analysis.

"Based on these data, we are continuing routine postoperative EEG monitoring in all neonates following surgery with cardiopulmonary bypass," said Dr. Naim.

While not discredited in any way, Dr. Naim’s data were met with a fair amount of pushback from the gathered group of pediatric cardiothoracic surgical experts. An informal poll of the audience showed that 80%-90% do not routinely monitor neonates for seizures post-CPB despite ACNS recommendations, and several of the comments questioned the technical and financial feasibility of routine EEG monitoring.

Said the invited discussant, Dr. Frank Pigula, a cardiac surgeon from Boston Children’s Hospital, "In all the groups that have studied this, in all patients who have had a seizure, there were documented brain abnormalities. So, the ways I picture these data are that a seizure is a sign of an underlying brain injury, much like a fever is a sign of an underlying infection."

"And you’ve made a good case for the routine postoperative surveillance for seizures; I’m sure everyone would agree that treating seizures is a good thing, but is there any evidence showing us that the early identification and treatment of seizures improves outcomes, either developmental delays or mortality?

In response, Dr. Naim noted that all the CHOP seizure sufferers were treated, whether they had EEG only or clinical seizures, and, at the 4-year mark, they are showing fewer neurodevelopmental issues than are previous cohorts of untreated neonates.

"I think one thing that is very concerning is emerging evidence that the seizures themselves cause secondary brain injury," she said. "So I think that the way to move forward, since our emphasis has really changed not to improving neurodevelopmental outcomes in our patients, is to monitor them postoperatively."

Dr. Naim reported having no financial disclosures. Dr. Pigula, the invited discussant, also reported no financial disclosures.

TORONTO – Routine EEG monitoring after surgery with cardiopulmonary bypass in neonates revealed a seizure incidence of 8% in a recent study. In most cases (85%), seizure activity was detectable only on EEG and would not have been identified or treated without EEG monitoring, reported Dr. Maryam Y. Naim, a critical care pediatrician at the Children’s Hospital of Philadelphia, during the American Association for Thoracic Surgery Annual Meeting.

Of concern, status epilepticus was noted in 62% of neonates with seizures, and mortality was higher in babies with seizures versus those without (38% vs. 3%; P less than .01).

"Postoperative seizures are associated with worse neurological outcomes," said Dr. Naim. In addition to being a biomarker of underlying brain injury, there is some evidence that the seizures themselves may cause secondary brain injury.

The American Clinical Neurophysiology Society (ACNS) recommends routine EEG monitoring following infant cardiac surgery. The CHOP group implemented this recommendation and performed a quality improvement study to determine the incidence of seizures in neonates following surgery with cardiopulmonary bypass (CBP).

A total of 161 neonates had 48-hours of EEG monitoring initiated within 6 hours of cardiac surgery with CPB. The median gestational age of the cohort was 39 weeks, 16% were premature, and 13% had identified genetic defects. The median age at the time of surgery was 5 days. Deep hypothermic circulatory arrest was used in 48% of surgeries (median time, 48 minutes), 16% had open chest with delayed sternal closure, and 9% had a cardiac arrest.

Seizures were detected in 13 (8%), with a median onset of 20 hours after return to the cardiac ICU (CICU) from surgery. Seizures were subclinical, or EEG only, in 11 patients (85%), electroclinical in the other 2 (15%), and status epilepticus was seen in 8 (62%).

When seizures occurred, the CICU team was notified by the EEG technologist, neurology consult was obtained, and the patient was treated with antiseizure medications. As well, abnormal vital signs or movements suggestive of seizure activity were noted at the bedside; although such events were recorded in 32 patients (22%), none had EEG correlates consistent with seizure activity.

"Neonates with all types of heart disease had seizures ... " reported Dr. Naim. " ... with a highest percentage occurring in those with single ventricles and arch obstruction."

Neuroimaging studies were reviewed by a neurologist to determine any association between injury and seizure location. The most commonly detected lesion was periventricular leukomalacia, and four patients had seizures arising from one of their injury sites.

Although neonates with and without seizures had similar CICU lengths of stay, mortality was higher in those with seizures (38% vs. 3%; P less than .01). No predictors of seizures were identified on multivariable analysis.

"Based on these data, we are continuing routine postoperative EEG monitoring in all neonates following surgery with cardiopulmonary bypass," said Dr. Naim.

While not discredited in any way, Dr. Naim’s data were met with a fair amount of pushback from the gathered group of pediatric cardiothoracic surgical experts. An informal poll of the audience showed that 80%-90% do not routinely monitor neonates for seizures post-CPB despite ACNS recommendations, and several of the comments questioned the technical and financial feasibility of routine EEG monitoring.

Said the invited discussant, Dr. Frank Pigula, a cardiac surgeon from Boston Children’s Hospital, "In all the groups that have studied this, in all patients who have had a seizure, there were documented brain abnormalities. So, the ways I picture these data are that a seizure is a sign of an underlying brain injury, much like a fever is a sign of an underlying infection."

"And you’ve made a good case for the routine postoperative surveillance for seizures; I’m sure everyone would agree that treating seizures is a good thing, but is there any evidence showing us that the early identification and treatment of seizures improves outcomes, either developmental delays or mortality?

In response, Dr. Naim noted that all the CHOP seizure sufferers were treated, whether they had EEG only or clinical seizures, and, at the 4-year mark, they are showing fewer neurodevelopmental issues than are previous cohorts of untreated neonates.

"I think one thing that is very concerning is emerging evidence that the seizures themselves cause secondary brain injury," she said. "So I think that the way to move forward, since our emphasis has really changed not to improving neurodevelopmental outcomes in our patients, is to monitor them postoperatively."

Dr. Naim reported having no financial disclosures. Dr. Pigula, the invited discussant, also reported no financial disclosures.

TORONTO – Routine EEG monitoring after surgery with cardiopulmonary bypass in neonates revealed a seizure incidence of 8% in a recent study. In most cases (85%), seizure activity was detectable only on EEG and would not have been identified or treated without EEG monitoring, reported Dr. Maryam Y. Naim, a critical care pediatrician at the Children’s Hospital of Philadelphia, during the American Association for Thoracic Surgery Annual Meeting.

Of concern, status epilepticus was noted in 62% of neonates with seizures, and mortality was higher in babies with seizures versus those without (38% vs. 3%; P less than .01).

"Postoperative seizures are associated with worse neurological outcomes," said Dr. Naim. In addition to being a biomarker of underlying brain injury, there is some evidence that the seizures themselves may cause secondary brain injury.

The American Clinical Neurophysiology Society (ACNS) recommends routine EEG monitoring following infant cardiac surgery. The CHOP group implemented this recommendation and performed a quality improvement study to determine the incidence of seizures in neonates following surgery with cardiopulmonary bypass (CBP).

A total of 161 neonates had 48-hours of EEG monitoring initiated within 6 hours of cardiac surgery with CPB. The median gestational age of the cohort was 39 weeks, 16% were premature, and 13% had identified genetic defects. The median age at the time of surgery was 5 days. Deep hypothermic circulatory arrest was used in 48% of surgeries (median time, 48 minutes), 16% had open chest with delayed sternal closure, and 9% had a cardiac arrest.

Seizures were detected in 13 (8%), with a median onset of 20 hours after return to the cardiac ICU (CICU) from surgery. Seizures were subclinical, or EEG only, in 11 patients (85%), electroclinical in the other 2 (15%), and status epilepticus was seen in 8 (62%).

When seizures occurred, the CICU team was notified by the EEG technologist, neurology consult was obtained, and the patient was treated with antiseizure medications. As well, abnormal vital signs or movements suggestive of seizure activity were noted at the bedside; although such events were recorded in 32 patients (22%), none had EEG correlates consistent with seizure activity.

"Neonates with all types of heart disease had seizures ... " reported Dr. Naim. " ... with a highest percentage occurring in those with single ventricles and arch obstruction."

Neuroimaging studies were reviewed by a neurologist to determine any association between injury and seizure location. The most commonly detected lesion was periventricular leukomalacia, and four patients had seizures arising from one of their injury sites.

Although neonates with and without seizures had similar CICU lengths of stay, mortality was higher in those with seizures (38% vs. 3%; P less than .01). No predictors of seizures were identified on multivariable analysis.

"Based on these data, we are continuing routine postoperative EEG monitoring in all neonates following surgery with cardiopulmonary bypass," said Dr. Naim.

While not discredited in any way, Dr. Naim’s data were met with a fair amount of pushback from the gathered group of pediatric cardiothoracic surgical experts. An informal poll of the audience showed that 80%-90% do not routinely monitor neonates for seizures post-CPB despite ACNS recommendations, and several of the comments questioned the technical and financial feasibility of routine EEG monitoring.

Said the invited discussant, Dr. Frank Pigula, a cardiac surgeon from Boston Children’s Hospital, "In all the groups that have studied this, in all patients who have had a seizure, there were documented brain abnormalities. So, the ways I picture these data are that a seizure is a sign of an underlying brain injury, much like a fever is a sign of an underlying infection."

"And you’ve made a good case for the routine postoperative surveillance for seizures; I’m sure everyone would agree that treating seizures is a good thing, but is there any evidence showing us that the early identification and treatment of seizures improves outcomes, either developmental delays or mortality?

In response, Dr. Naim noted that all the CHOP seizure sufferers were treated, whether they had EEG only or clinical seizures, and, at the 4-year mark, they are showing fewer neurodevelopmental issues than are previous cohorts of untreated neonates.

"I think one thing that is very concerning is emerging evidence that the seizures themselves cause secondary brain injury," she said. "So I think that the way to move forward, since our emphasis has really changed not to improving neurodevelopmental outcomes in our patients, is to monitor them postoperatively."

Dr. Naim reported having no financial disclosures. Dr. Pigula, the invited discussant, also reported no financial disclosures.