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WASHINGTON – Consistent with experimental and recent clinical studies, a meta-analysis of 69 randomized controlled trials found that increasing strut thickness correlated with increasing risk of stent thrombosis as well as risk of myocardial infarction.
The report was presented at CRT 2018, sponsored by the Cardiovascular Research Institute at Medstar Washington (D.C.) Hospital Center.
In the meta-analysis, which compared four categories of strut thickness, the relationship between strut thickness and rates of stent thrombosis was almost linear, according to Micaela Iantorno, MD, a clinical fellow in interventional cardiology at the hospital center.
Thirty-six of the studies compared devices with thin struts to those with thick struts, 15 studies compared devices with ultrathin struts to devices with thin struts, and 11 compared devices with thin struts to devices with struts in the intermediate category. The remaining seven studies compared other strut thicknesses, such as ultrathin to intermediate.
When compared to devices with the thickest struts, there was a stepwise reduction in risk of strut thrombosis for each grade reduction in thickness. Expressed as an odds ratio, devices with intermediate struts were associated with 33% risk reduction, devices with thin struts were associated with a 42% risk reduction, and devices with ultrathin struts were associated with a 57% risk reduction. Each was statistically significant based on the 95% confidence interval, although P values were not reported.
When devices with ultrathin struts were compared to those with thin struts or to those with intermediate thickness struts, the differences in stent thrombosis were not statistically significant, but there were trends favoring the devices with thinner struts. However, the lower risk of stent thrombosis for devices with thin struts relative to those with intermediate thickness was modest and did not approach significance.
For risk of MI, the same type of gradient was observed. Relative to devices with thick struts, devices with ultrathin struts were associated with a 27% reduction, devices with thin struts were associated with a 21% reduction, and devices with struts of intermediate thickness were associated with a 15% reduction. Only the difference for the intermediate-thickness devices fell short of statistical significance.
There were 22 different stent devices represented in this analysis. Bare metal stents and stents with bioresorbable scaffolds were excluded, but devices from all three generations of drug-eluting stents, including devices with bioabsorbable polymers, were included.
Other outcomes, including mortality, cardiovascular mortality, and major adverse cardiovascular events, were evaluated, but a gradient relationship between strut thickness and these outcomes was less apparent. For example, when devices with thick struts were compared to devices with thinner struts, only the ultrathin devices achieved a significant, 15%, reduction in cardiovascular mortality. The 10% reduction in all-cause mortality fell short of statistical significance.
Emphasizing that other factors, such as stent geometry, polymer type, and type of eluting drug, were not considered in this analysis, Dr. Iantorno acknowledged that there are important limitations of this study, but the data are consistent with the hypothesis that “reducing strut thickness might be the key to improving the efficacy and safety profile of coronary stents.”
Sachin Kumar, MD, an interventional cardiologist at the University of Texas Health Science Center at Houston, cautioned that strut thickness “is just one side of the story.” Moderator of the session in which these data were presented, Dr. Kumar said that other factors Dr. Iantorno listed as potentially important, including polymer type and eluting drug, should not be discounted. However, he conceded that in the context of other recent evidence that strut thickness may be important to outcomes, particularly risk of stent thrombosis, this variable has become a focus of design improvements.
SOURCE: Iantorno M. Abstract CRT-100.87.
WASHINGTON – Consistent with experimental and recent clinical studies, a meta-analysis of 69 randomized controlled trials found that increasing strut thickness correlated with increasing risk of stent thrombosis as well as risk of myocardial infarction.
The report was presented at CRT 2018, sponsored by the Cardiovascular Research Institute at Medstar Washington (D.C.) Hospital Center.
In the meta-analysis, which compared four categories of strut thickness, the relationship between strut thickness and rates of stent thrombosis was almost linear, according to Micaela Iantorno, MD, a clinical fellow in interventional cardiology at the hospital center.
Thirty-six of the studies compared devices with thin struts to those with thick struts, 15 studies compared devices with ultrathin struts to devices with thin struts, and 11 compared devices with thin struts to devices with struts in the intermediate category. The remaining seven studies compared other strut thicknesses, such as ultrathin to intermediate.
When compared to devices with the thickest struts, there was a stepwise reduction in risk of strut thrombosis for each grade reduction in thickness. Expressed as an odds ratio, devices with intermediate struts were associated with 33% risk reduction, devices with thin struts were associated with a 42% risk reduction, and devices with ultrathin struts were associated with a 57% risk reduction. Each was statistically significant based on the 95% confidence interval, although P values were not reported.
When devices with ultrathin struts were compared to those with thin struts or to those with intermediate thickness struts, the differences in stent thrombosis were not statistically significant, but there were trends favoring the devices with thinner struts. However, the lower risk of stent thrombosis for devices with thin struts relative to those with intermediate thickness was modest and did not approach significance.
For risk of MI, the same type of gradient was observed. Relative to devices with thick struts, devices with ultrathin struts were associated with a 27% reduction, devices with thin struts were associated with a 21% reduction, and devices with struts of intermediate thickness were associated with a 15% reduction. Only the difference for the intermediate-thickness devices fell short of statistical significance.
There were 22 different stent devices represented in this analysis. Bare metal stents and stents with bioresorbable scaffolds were excluded, but devices from all three generations of drug-eluting stents, including devices with bioabsorbable polymers, were included.
Other outcomes, including mortality, cardiovascular mortality, and major adverse cardiovascular events, were evaluated, but a gradient relationship between strut thickness and these outcomes was less apparent. For example, when devices with thick struts were compared to devices with thinner struts, only the ultrathin devices achieved a significant, 15%, reduction in cardiovascular mortality. The 10% reduction in all-cause mortality fell short of statistical significance.
Emphasizing that other factors, such as stent geometry, polymer type, and type of eluting drug, were not considered in this analysis, Dr. Iantorno acknowledged that there are important limitations of this study, but the data are consistent with the hypothesis that “reducing strut thickness might be the key to improving the efficacy and safety profile of coronary stents.”
Sachin Kumar, MD, an interventional cardiologist at the University of Texas Health Science Center at Houston, cautioned that strut thickness “is just one side of the story.” Moderator of the session in which these data were presented, Dr. Kumar said that other factors Dr. Iantorno listed as potentially important, including polymer type and eluting drug, should not be discounted. However, he conceded that in the context of other recent evidence that strut thickness may be important to outcomes, particularly risk of stent thrombosis, this variable has become a focus of design improvements.
SOURCE: Iantorno M. Abstract CRT-100.87.
WASHINGTON – Consistent with experimental and recent clinical studies, a meta-analysis of 69 randomized controlled trials found that increasing strut thickness correlated with increasing risk of stent thrombosis as well as risk of myocardial infarction.
The report was presented at CRT 2018, sponsored by the Cardiovascular Research Institute at Medstar Washington (D.C.) Hospital Center.
In the meta-analysis, which compared four categories of strut thickness, the relationship between strut thickness and rates of stent thrombosis was almost linear, according to Micaela Iantorno, MD, a clinical fellow in interventional cardiology at the hospital center.
Thirty-six of the studies compared devices with thin struts to those with thick struts, 15 studies compared devices with ultrathin struts to devices with thin struts, and 11 compared devices with thin struts to devices with struts in the intermediate category. The remaining seven studies compared other strut thicknesses, such as ultrathin to intermediate.
When compared to devices with the thickest struts, there was a stepwise reduction in risk of strut thrombosis for each grade reduction in thickness. Expressed as an odds ratio, devices with intermediate struts were associated with 33% risk reduction, devices with thin struts were associated with a 42% risk reduction, and devices with ultrathin struts were associated with a 57% risk reduction. Each was statistically significant based on the 95% confidence interval, although P values were not reported.
When devices with ultrathin struts were compared to those with thin struts or to those with intermediate thickness struts, the differences in stent thrombosis were not statistically significant, but there were trends favoring the devices with thinner struts. However, the lower risk of stent thrombosis for devices with thin struts relative to those with intermediate thickness was modest and did not approach significance.
For risk of MI, the same type of gradient was observed. Relative to devices with thick struts, devices with ultrathin struts were associated with a 27% reduction, devices with thin struts were associated with a 21% reduction, and devices with struts of intermediate thickness were associated with a 15% reduction. Only the difference for the intermediate-thickness devices fell short of statistical significance.
There were 22 different stent devices represented in this analysis. Bare metal stents and stents with bioresorbable scaffolds were excluded, but devices from all three generations of drug-eluting stents, including devices with bioabsorbable polymers, were included.
Other outcomes, including mortality, cardiovascular mortality, and major adverse cardiovascular events, were evaluated, but a gradient relationship between strut thickness and these outcomes was less apparent. For example, when devices with thick struts were compared to devices with thinner struts, only the ultrathin devices achieved a significant, 15%, reduction in cardiovascular mortality. The 10% reduction in all-cause mortality fell short of statistical significance.
Emphasizing that other factors, such as stent geometry, polymer type, and type of eluting drug, were not considered in this analysis, Dr. Iantorno acknowledged that there are important limitations of this study, but the data are consistent with the hypothesis that “reducing strut thickness might be the key to improving the efficacy and safety profile of coronary stents.”
Sachin Kumar, MD, an interventional cardiologist at the University of Texas Health Science Center at Houston, cautioned that strut thickness “is just one side of the story.” Moderator of the session in which these data were presented, Dr. Kumar said that other factors Dr. Iantorno listed as potentially important, including polymer type and eluting drug, should not be discounted. However, he conceded that in the context of other recent evidence that strut thickness may be important to outcomes, particularly risk of stent thrombosis, this variable has become a focus of design improvements.
SOURCE: Iantorno M. Abstract CRT-100.87.
REPORTING FROM CRT 2018
Key clinical point: The thickness of struts in drug-eluting stents is inversely related to the risk of stent thrombosis.
Major finding: The risk of stent thrombosis is 57% lower for DES devices with ultrathin (less than 81 mcg) rather than thick (at least 121 mcg) struts.
Data source: Meta-analysis of randomized trials.
Disclosures: Dr. Iantorno reports no financial relationships relevant to this study.
Source: Iantorno M. Abstract CRT-100.87.