ISC 2012

NEW ORLEANS – Continuous cardiac outpatient telemetry monitoring for at least 21 days may be necessary to accurately identify atrial fibrillation as the cause of cryptogenic stroke, according to the results of a single-center, retrospective study.

Identifying these patients is important because many could be treated with anticoagulants that would reduce their stroke risk, said Dr. Daniel J. Miller, a neurologist at Henry Ford Hospital, Detroit.

About a third of all strokes are of unknown etiology. Paroxysmal atrial fibrillation (AF) is a potential cause of cryptogenic stroke and transient ischemic attacks (TIAs), and carries a high risk of future strokes, Dr. Miller said during a press briefing at the International Stroke Conference.

Physicians have not been sure about the best way to monitor these patients or how long to monitor them.

He and his colleagues followed-up on two small studies: one conducted by Dr. Ashis H. Tayal and colleagues (Neurology 2008;71:1696-1701) and another by Dr. Archit Bhatt and associates (Stroke Res. Treat. 2011 [doi:10.4061/2011/172074]). The Tayal study showed a 23% AF detection rate in cryptogenic stroke patients monitored for longer than 21 days. The Bhatt study found a similar AF rate in cryptogenic stroke.

Dr. Miller and his coinvestigators reviewed the records of 156 Henry Ford Hospital patients who’d had a cryptogenic stroke or TIA and had undergone monitoring with the Cardionet Mobile Cardiac Outpatient Telemetry (MCOT) device, which is commonly used at Henry Ford

The patients had a mean age of 68 years and half were women. The vast majority (97%) were not taking an anticoagulant. Hypertension was common, present in 87% of the patients. They had a fairly low mean score of 3 on the National Institutes of Health Stroke Scale (NIHSS), indicating that the stroke had not been severe.

After monitoring, 27 (17.3%) of the 156 patients had paroxysmal AF. The AF events lasted less than 30 seconds in two-thirds of the patients and longer than 30 seconds in 26%. The remaining 8% had persistently occurring AF. This finding was not surprising and was consistent with the Tayal report, Dr. Miller said in an interview. The monitors are very sensitive, in particular for those events longer than 30 seconds, but they might miss some episodes of less than 30 seconds, he said.

The review showed that the rate of AF detection rose with increased duration of monitoring. The detection rate on a Kaplan-Meier curve was estimated to be 4% at 48 hours, 9% at 7 days, 14% at 14 days, and 20% by 21 days. "Our study does show that in order to capture all these events you should continue to monitor for at least 21 days," Dr. Miller said.

A multivariate Cox regression analysis showed that for all patients, female gender (P = .002), premature atrial complexes (PAC) on electrocardiogram (P = .001), a 1-cm increase in the diameter of the left atrium (P = .033), and a 10% decline in left ventricular ejection fraction (P = .008) all were associated with increased risk of AF. For stroke patients, female gender, PAC, and increasing stroke severity on the NIHSS were all associated with increased risk.

PAC, a premature beat from the atrium, has been shown to be associated with AF. It was an especially strong predictor of AF in this study, Dr. Miller said.

He urged further study to determine optimal monitoring beyond 21 days for patients with cryptogenic stroke or TIA.

NEW ORLEANS – Continuous cardiac outpatient telemetry monitoring for at least 21 days may be necessary to accurately identify atrial fibrillation as the cause of cryptogenic stroke, according to the results of a single-center, retrospective study.

Identifying these patients is important because many could be treated with anticoagulants that would reduce their stroke risk, said Dr. Daniel J. Miller, a neurologist at Henry Ford Hospital, Detroit.

About a third of all strokes are of unknown etiology. Paroxysmal atrial fibrillation (AF) is a potential cause of cryptogenic stroke and transient ischemic attacks (TIAs), and carries a high risk of future strokes, Dr. Miller said during a press briefing at the International Stroke Conference.

Physicians have not been sure about the best way to monitor these patients or how long to monitor them.

He and his colleagues followed-up on two small studies: one conducted by Dr. Ashis H. Tayal and colleagues (Neurology 2008;71:1696-1701) and another by Dr. Archit Bhatt and associates (Stroke Res. Treat. 2011 [doi:10.4061/2011/172074]). The Tayal study showed a 23% AF detection rate in cryptogenic stroke patients monitored for longer than 21 days. The Bhatt study found a similar AF rate in cryptogenic stroke.

Dr. Miller and his coinvestigators reviewed the records of 156 Henry Ford Hospital patients who’d had a cryptogenic stroke or TIA and had undergone monitoring with the Cardionet Mobile Cardiac Outpatient Telemetry (MCOT) device, which is commonly used at Henry Ford

The patients had a mean age of 68 years and half were women. The vast majority (97%) were not taking an anticoagulant. Hypertension was common, present in 87% of the patients. They had a fairly low mean score of 3 on the National Institutes of Health Stroke Scale (NIHSS), indicating that the stroke had not been severe.

After monitoring, 27 (17.3%) of the 156 patients had paroxysmal AF. The AF events lasted less than 30 seconds in two-thirds of the patients and longer than 30 seconds in 26%. The remaining 8% had persistently occurring AF. This finding was not surprising and was consistent with the Tayal report, Dr. Miller said in an interview. The monitors are very sensitive, in particular for those events longer than 30 seconds, but they might miss some episodes of less than 30 seconds, he said.

The review showed that the rate of AF detection rose with increased duration of monitoring. The detection rate on a Kaplan-Meier curve was estimated to be 4% at 48 hours, 9% at 7 days, 14% at 14 days, and 20% by 21 days. "Our study does show that in order to capture all these events you should continue to monitor for at least 21 days," Dr. Miller said.

A multivariate Cox regression analysis showed that for all patients, female gender (P = .002), premature atrial complexes (PAC) on electrocardiogram (P = .001), a 1-cm increase in the diameter of the left atrium (P = .033), and a 10% decline in left ventricular ejection fraction (P = .008) all were associated with increased risk of AF. For stroke patients, female gender, PAC, and increasing stroke severity on the NIHSS were all associated with increased risk.

PAC, a premature beat from the atrium, has been shown to be associated with AF. It was an especially strong predictor of AF in this study, Dr. Miller said.

He urged further study to determine optimal monitoring beyond 21 days for patients with cryptogenic stroke or TIA.

NEW ORLEANS – Continuous cardiac outpatient telemetry monitoring for at least 21 days may be necessary to accurately identify atrial fibrillation as the cause of cryptogenic stroke, according to the results of a single-center, retrospective study.

Identifying these patients is important because many could be treated with anticoagulants that would reduce their stroke risk, said Dr. Daniel J. Miller, a neurologist at Henry Ford Hospital, Detroit.

About a third of all strokes are of unknown etiology. Paroxysmal atrial fibrillation (AF) is a potential cause of cryptogenic stroke and transient ischemic attacks (TIAs), and carries a high risk of future strokes, Dr. Miller said during a press briefing at the International Stroke Conference.

Physicians have not been sure about the best way to monitor these patients or how long to monitor them.

He and his colleagues followed-up on two small studies: one conducted by Dr. Ashis H. Tayal and colleagues (Neurology 2008;71:1696-1701) and another by Dr. Archit Bhatt and associates (Stroke Res. Treat. 2011 [doi:10.4061/2011/172074]). The Tayal study showed a 23% AF detection rate in cryptogenic stroke patients monitored for longer than 21 days. The Bhatt study found a similar AF rate in cryptogenic stroke.

Dr. Miller and his coinvestigators reviewed the records of 156 Henry Ford Hospital patients who’d had a cryptogenic stroke or TIA and had undergone monitoring with the Cardionet Mobile Cardiac Outpatient Telemetry (MCOT) device, which is commonly used at Henry Ford

The patients had a mean age of 68 years and half were women. The vast majority (97%) were not taking an anticoagulant. Hypertension was common, present in 87% of the patients. They had a fairly low mean score of 3 on the National Institutes of Health Stroke Scale (NIHSS), indicating that the stroke had not been severe.

After monitoring, 27 (17.3%) of the 156 patients had paroxysmal AF. The AF events lasted less than 30 seconds in two-thirds of the patients and longer than 30 seconds in 26%. The remaining 8% had persistently occurring AF. This finding was not surprising and was consistent with the Tayal report, Dr. Miller said in an interview. The monitors are very sensitive, in particular for those events longer than 30 seconds, but they might miss some episodes of less than 30 seconds, he said.

The review showed that the rate of AF detection rose with increased duration of monitoring. The detection rate on a Kaplan-Meier curve was estimated to be 4% at 48 hours, 9% at 7 days, 14% at 14 days, and 20% by 21 days. "Our study does show that in order to capture all these events you should continue to monitor for at least 21 days," Dr. Miller said.

A multivariate Cox regression analysis showed that for all patients, female gender (P = .002), premature atrial complexes (PAC) on electrocardiogram (P = .001), a 1-cm increase in the diameter of the left atrium (P = .033), and a 10% decline in left ventricular ejection fraction (P = .008) all were associated with increased risk of AF. For stroke patients, female gender, PAC, and increasing stroke severity on the NIHSS were all associated with increased risk.

PAC, a premature beat from the atrium, has been shown to be associated with AF. It was an especially strong predictor of AF in this study, Dr. Miller said.

He urged further study to determine optimal monitoring beyond 21 days for patients with cryptogenic stroke or TIA.

NEW ORLEANS – There may be a correlation between infection and stroke in children, according to research presented at the International Stroke Conference.

Acute infection is considered to be a risk factor for stroke in adults, so researchers from the University of California, San Francisco, decided to study whether it might also be a potential risk in children, who experience frequent infections.

Stroke, however, is still extremely rare in children: The incidence of acute arterial ischemic stroke is 2.4 per 100,000 children annually in the United States. A large proportion of those cases have no known cause, said Nancy K. Hills, Ph.D., assistant adjunct professor of neurology at UCSF, at a press briefing. Many of those children, however, have an underlying arteriopathy.

Dr. Hills and her colleagues found that children who had a stroke were eight times more likely to have visited a health provider for an infection within 1 month before the stroke, compared with controls. More than 1 month before the stroke, however, there was no difference in the number of visits for infection between cases and controls. The researchers could not prove a direct link between infection and stroke. "We really believe it’s not the infection that’s causing the stroke," Dr. Hills said.

"It’s not something that parents of healthy children need to worry about," she said, adding that the infections are "probably a trigger for something else." The researchers believe that the children who had infection and stroke "probably have some underlying predisposition that causes them to have an unusual response to a common infection."

The retrospective study examined medical records for 2.5 million children – aged 29 days to 19 years – who were members of Kaiser Permanente from 1993 to 2007. The investigators identified 126 acute ischemic strokes, and then randomly selected 378 age-matched controls (three controls per case) from the Kaiser population. The median age was 10.5 years, and there was a relatively similar mix of male and females. All races were proportionately represented, said Dr. Hills.

The researchers looked at both diagnosed infections and symptoms that were indicative of infection. Any history of infection after a stroke diagnosis was excluded. Once the index stroke was established, the researchers categorized infectious visits according to time frames: 0-2 days, 3-7 days, 8-28 days, 1-3 months, 3-6 months, 6-12 months, and 12-24 months before the stroke.

They found that children who had a stroke were much more likely to have had a visit for infection within 1 month of the index stroke (odds ratio, 8.37). The odds ratio increased to 182 for a visit for infection within 2 days of the stroke. Twenty-nine percent of those who had a stroke had a visit in the 2 days prior to the stroke, compared with 1% of controls for the same dates. In the 3- to 7-day window, 13% of children who had a stroke had an infection, compared with 2% of controls.

The authors concluded that the risk of stroke is substantially elevated within the week after a visit for infection, but that it is likely that these children have some susceptibility to stroke, and that the infection puts them in a prothrombotic state, Dr. Hills said at the meeting, which was sponsored by the American Heart Association.

She pointed out several limitations to the study, including the fact that the number of infections in both the cases and controls was likely underestimated. Also, the infections were not generally confirmed by lab data; they were based on empirical diagnoses.

The study was funded by the National Institute of Neurological Disorders and Stroke. The authors reported no relevant financial conflicts.

NEW ORLEANS – There may be a correlation between infection and stroke in children, according to research presented at the International Stroke Conference.

Acute infection is considered to be a risk factor for stroke in adults, so researchers from the University of California, San Francisco, decided to study whether it might also be a potential risk in children, who experience frequent infections.

Stroke, however, is still extremely rare in children: The incidence of acute arterial ischemic stroke is 2.4 per 100,000 children annually in the United States. A large proportion of those cases have no known cause, said Nancy K. Hills, Ph.D., assistant adjunct professor of neurology at UCSF, at a press briefing. Many of those children, however, have an underlying arteriopathy.

Dr. Hills and her colleagues found that children who had a stroke were eight times more likely to have visited a health provider for an infection within 1 month before the stroke, compared with controls. More than 1 month before the stroke, however, there was no difference in the number of visits for infection between cases and controls. The researchers could not prove a direct link between infection and stroke. "We really believe it’s not the infection that’s causing the stroke," Dr. Hills said.

"It’s not something that parents of healthy children need to worry about," she said, adding that the infections are "probably a trigger for something else." The researchers believe that the children who had infection and stroke "probably have some underlying predisposition that causes them to have an unusual response to a common infection."

The retrospective study examined medical records for 2.5 million children – aged 29 days to 19 years – who were members of Kaiser Permanente from 1993 to 2007. The investigators identified 126 acute ischemic strokes, and then randomly selected 378 age-matched controls (three controls per case) from the Kaiser population. The median age was 10.5 years, and there was a relatively similar mix of male and females. All races were proportionately represented, said Dr. Hills.

The researchers looked at both diagnosed infections and symptoms that were indicative of infection. Any history of infection after a stroke diagnosis was excluded. Once the index stroke was established, the researchers categorized infectious visits according to time frames: 0-2 days, 3-7 days, 8-28 days, 1-3 months, 3-6 months, 6-12 months, and 12-24 months before the stroke.

They found that children who had a stroke were much more likely to have had a visit for infection within 1 month of the index stroke (odds ratio, 8.37). The odds ratio increased to 182 for a visit for infection within 2 days of the stroke. Twenty-nine percent of those who had a stroke had a visit in the 2 days prior to the stroke, compared with 1% of controls for the same dates. In the 3- to 7-day window, 13% of children who had a stroke had an infection, compared with 2% of controls.

The authors concluded that the risk of stroke is substantially elevated within the week after a visit for infection, but that it is likely that these children have some susceptibility to stroke, and that the infection puts them in a prothrombotic state, Dr. Hills said at the meeting, which was sponsored by the American Heart Association.

She pointed out several limitations to the study, including the fact that the number of infections in both the cases and controls was likely underestimated. Also, the infections were not generally confirmed by lab data; they were based on empirical diagnoses.

The study was funded by the National Institute of Neurological Disorders and Stroke. The authors reported no relevant financial conflicts.

NEW ORLEANS – There may be a correlation between infection and stroke in children, according to research presented at the International Stroke Conference.

Acute infection is considered to be a risk factor for stroke in adults, so researchers from the University of California, San Francisco, decided to study whether it might also be a potential risk in children, who experience frequent infections.

Stroke, however, is still extremely rare in children: The incidence of acute arterial ischemic stroke is 2.4 per 100,000 children annually in the United States. A large proportion of those cases have no known cause, said Nancy K. Hills, Ph.D., assistant adjunct professor of neurology at UCSF, at a press briefing. Many of those children, however, have an underlying arteriopathy.

Dr. Hills and her colleagues found that children who had a stroke were eight times more likely to have visited a health provider for an infection within 1 month before the stroke, compared with controls. More than 1 month before the stroke, however, there was no difference in the number of visits for infection between cases and controls. The researchers could not prove a direct link between infection and stroke. "We really believe it’s not the infection that’s causing the stroke," Dr. Hills said.

"It’s not something that parents of healthy children need to worry about," she said, adding that the infections are "probably a trigger for something else." The researchers believe that the children who had infection and stroke "probably have some underlying predisposition that causes them to have an unusual response to a common infection."

The retrospective study examined medical records for 2.5 million children – aged 29 days to 19 years – who were members of Kaiser Permanente from 1993 to 2007. The investigators identified 126 acute ischemic strokes, and then randomly selected 378 age-matched controls (three controls per case) from the Kaiser population. The median age was 10.5 years, and there was a relatively similar mix of male and females. All races were proportionately represented, said Dr. Hills.

The researchers looked at both diagnosed infections and symptoms that were indicative of infection. Any history of infection after a stroke diagnosis was excluded. Once the index stroke was established, the researchers categorized infectious visits according to time frames: 0-2 days, 3-7 days, 8-28 days, 1-3 months, 3-6 months, 6-12 months, and 12-24 months before the stroke.

They found that children who had a stroke were much more likely to have had a visit for infection within 1 month of the index stroke (odds ratio, 8.37). The odds ratio increased to 182 for a visit for infection within 2 days of the stroke. Twenty-nine percent of those who had a stroke had a visit in the 2 days prior to the stroke, compared with 1% of controls for the same dates. In the 3- to 7-day window, 13% of children who had a stroke had an infection, compared with 2% of controls.

The authors concluded that the risk of stroke is substantially elevated within the week after a visit for infection, but that it is likely that these children have some susceptibility to stroke, and that the infection puts them in a prothrombotic state, Dr. Hills said at the meeting, which was sponsored by the American Heart Association.

She pointed out several limitations to the study, including the fact that the number of infections in both the cases and controls was likely underestimated. Also, the infections were not generally confirmed by lab data; they were based on empirical diagnoses.

The study was funded by the National Institute of Neurological Disorders and Stroke. The authors reported no relevant financial conflicts.

NEW ORLEANS – Memory is already impaired years before a stroke occurs, declining most rapidly in people destined to suffer a fatal stroke, according to a population-based study of more than 11,000 people.

"For every year that passed [after age 50 years], those who survived a stroke lost their memory at twice the rate as controls. And for those who didn’t survive, their annual memory loss was 3 to 4 years faster than the controls," said Maria Glymour, Sc.D., of the Harvard University School of Public Health, Boston.*

Dr. Glymour and her colleagues examined the relationship between memory and stroke using data from the national Health and Retirement Study (HRS) cohort of people aged 50 years or older.

Interviews with the study’s participants occurred every 2 years, starting in 1998. In their 10-year follow-up study, the investigators focused on 1,456 people who had survived a stroke, 364 who died from a stroke, and 9,994 who did not have a stroke. An immediate and delayed word list recall task, included in the HRS, served as the proxy for working memory among the group.

As expected, Dr. Glymour and her associates found trajectories showing age-related memory decline among all subjects after their baseline interview.

There were also baseline differences between the groups. People who had a stroke – both survivors and nonsurvivors – had significantly poorer memory function at the beginning of the follow-up period.

"More than half of the memory gap between recent stroke survivors and stroke-free adults of similar age was evident before the stroke," she said during a press briefing at the International Stroke Conference.

The groups continued to separate as the years progressed, although individuals in all three groups had trajectories of at least some age-related memory decline during the 10-year follow-up period.

The study did not assess total cognitive ability, so Dr. Glymour could not say how many in each group already had some basis for memory impairment. But even among the stroke groups, many subjects started out with high function, she noted. "It was the rate of decline that was the key factor."

"We are really interested to know what’s going on in the brains of these people that seems to be related to having a stroke. My guess is that there is a physiologic basis – that there might be some subclinical strokes that have already occurred that affect memory."

Another possibility could be memory-related behavioral issues, she said. "If people are already having trouble with memory, they might have a harder time controlling their stroke risks – for example, taking their blood pressure medications."

Dr. Steven Greenberg, director of the Hemorrhagic Stroke Research Program at Massachusetts General Hospital, Boston, and an American Heart Association spokesman, agreed.

"The cause and effect are still a little unclear. But one possibility is this idea of unnoticed strokes going on over time that cause people to have such a bad trajectory of memory loss. When they do have a symptomatic stroke, they have very little reserve left."

The study was sponsored by the National Institutes of Health. None of the investigators or Dr. Greenberg had any relevant financial disclosures.

*This story was updated 2/2/2012.

NEW ORLEANS – Memory is already impaired years before a stroke occurs, declining most rapidly in people destined to suffer a fatal stroke, according to a population-based study of more than 11,000 people.

"For every year that passed [after age 50 years], those who survived a stroke lost their memory at twice the rate as controls. And for those who didn’t survive, their annual memory loss was 3 to 4 years faster than the controls," said Maria Glymour, Sc.D., of the Harvard University School of Public Health, Boston.*

Dr. Glymour and her colleagues examined the relationship between memory and stroke using data from the national Health and Retirement Study (HRS) cohort of people aged 50 years or older.

Interviews with the study’s participants occurred every 2 years, starting in 1998. In their 10-year follow-up study, the investigators focused on 1,456 people who had survived a stroke, 364 who died from a stroke, and 9,994 who did not have a stroke. An immediate and delayed word list recall task, included in the HRS, served as the proxy for working memory among the group.

As expected, Dr. Glymour and her associates found trajectories showing age-related memory decline among all subjects after their baseline interview.

There were also baseline differences between the groups. People who had a stroke – both survivors and nonsurvivors – had significantly poorer memory function at the beginning of the follow-up period.

"More than half of the memory gap between recent stroke survivors and stroke-free adults of similar age was evident before the stroke," she said during a press briefing at the International Stroke Conference.

The groups continued to separate as the years progressed, although individuals in all three groups had trajectories of at least some age-related memory decline during the 10-year follow-up period.

The study did not assess total cognitive ability, so Dr. Glymour could not say how many in each group already had some basis for memory impairment. But even among the stroke groups, many subjects started out with high function, she noted. "It was the rate of decline that was the key factor."

"We are really interested to know what’s going on in the brains of these people that seems to be related to having a stroke. My guess is that there is a physiologic basis – that there might be some subclinical strokes that have already occurred that affect memory."

Another possibility could be memory-related behavioral issues, she said. "If people are already having trouble with memory, they might have a harder time controlling their stroke risks – for example, taking their blood pressure medications."

Dr. Steven Greenberg, director of the Hemorrhagic Stroke Research Program at Massachusetts General Hospital, Boston, and an American Heart Association spokesman, agreed.

"The cause and effect are still a little unclear. But one possibility is this idea of unnoticed strokes going on over time that cause people to have such a bad trajectory of memory loss. When they do have a symptomatic stroke, they have very little reserve left."

The study was sponsored by the National Institutes of Health. None of the investigators or Dr. Greenberg had any relevant financial disclosures.

*This story was updated 2/2/2012.

NEW ORLEANS – Memory is already impaired years before a stroke occurs, declining most rapidly in people destined to suffer a fatal stroke, according to a population-based study of more than 11,000 people.

"For every year that passed [after age 50 years], those who survived a stroke lost their memory at twice the rate as controls. And for those who didn’t survive, their annual memory loss was 3 to 4 years faster than the controls," said Maria Glymour, Sc.D., of the Harvard University School of Public Health, Boston.*

Dr. Glymour and her colleagues examined the relationship between memory and stroke using data from the national Health and Retirement Study (HRS) cohort of people aged 50 years or older.

Interviews with the study’s participants occurred every 2 years, starting in 1998. In their 10-year follow-up study, the investigators focused on 1,456 people who had survived a stroke, 364 who died from a stroke, and 9,994 who did not have a stroke. An immediate and delayed word list recall task, included in the HRS, served as the proxy for working memory among the group.

As expected, Dr. Glymour and her associates found trajectories showing age-related memory decline among all subjects after their baseline interview.

There were also baseline differences between the groups. People who had a stroke – both survivors and nonsurvivors – had significantly poorer memory function at the beginning of the follow-up period.

"More than half of the memory gap between recent stroke survivors and stroke-free adults of similar age was evident before the stroke," she said during a press briefing at the International Stroke Conference.

The groups continued to separate as the years progressed, although individuals in all three groups had trajectories of at least some age-related memory decline during the 10-year follow-up period.

The study did not assess total cognitive ability, so Dr. Glymour could not say how many in each group already had some basis for memory impairment. But even among the stroke groups, many subjects started out with high function, she noted. "It was the rate of decline that was the key factor."

"We are really interested to know what’s going on in the brains of these people that seems to be related to having a stroke. My guess is that there is a physiologic basis – that there might be some subclinical strokes that have already occurred that affect memory."

Another possibility could be memory-related behavioral issues, she said. "If people are already having trouble with memory, they might have a harder time controlling their stroke risks – for example, taking their blood pressure medications."

Dr. Steven Greenberg, director of the Hemorrhagic Stroke Research Program at Massachusetts General Hospital, Boston, and an American Heart Association spokesman, agreed.

"The cause and effect are still a little unclear. But one possibility is this idea of unnoticed strokes going on over time that cause people to have such a bad trajectory of memory loss. When they do have a symptomatic stroke, they have very little reserve left."

The study was sponsored by the National Institutes of Health. None of the investigators or Dr. Greenberg had any relevant financial disclosures.

*This story was updated 2/2/2012.