Carotid Bypass Surgery May Not Improve Cognition After Stroke

HONOLULU—Restoring adequate blood flow to the brain through surgery to bypass a blocked carotid artery may not improve cognitive performance in patients who have had a stroke or transient ischemic attack (TIA), investigators reported at the 2013 International Stroke Conference.

Randolph S. Marshall, MD, Elizabeth K. Harris Professor of Neurology at Columbia University Medical Center in New York City, and colleagues conducted the Randomized Evaluation of Carotid Occlusion and Neurocognition (RECON) study to determine whether bypass surgery could preserve or improve cognition over two years. Patients’ mean age was 57.1. Twenty-five men and 10 women were randomized to optimal medical treatment or optimal medical treatment and extracranial¬–intracranial (EC–IC) bypass. During EC–IC bypass, a surgeon connects a scalp artery outside the skull to a brain artery inside the skull through a small hole, thus bypassing the blocked carotid artery to increase blood flow to the brain.

All patients had had a stroke or TIA caused by a clot and had had cognition problems. Common cognition problems included mild short-term memory loss, poor concentration, and not feeling mentally acute. The most common abnormalities on cognitive testing were needing increased time to complete timed tasks or to perform tasks that required alternating between different types of information.

Of the 35 patients, 28 survived without a subsequent stroke to undergo the two-year cognitive evaluation. Fifteen of these patients were on optimal medical treatment, and 13 were on optimal medical treatment and had had EC–IC bypass. At baseline, patients with the worst blood flow had the worst cognitive problems. Patients who had better blood flow to the brain at baseline, and patients who had a TIA rather than a stroke, had the most cognitive improvement at follow-up. Final results indicated that surgery was no better than medical therapy at preserving or improving cognitive function at two years after treatment initiation.

“One problem that could partly explain the negative results was that only three out of 13 patients in the surgical group actually achieved normal blood flow after the operation,” said Dr. Marshall in a press release. “It’s still quite likely that cognitive impairment due to a low blood flow state represents one of the only reversible types of dementia,” he added. “Besides this bypass operation, there are other ways of achieving better blood flow, both mechanical and pharmacological, so the next direction for this work is to find a treatment that has a better chance of improving blood flow with fewer complications.”

RECON was an ancillary trial of the Carotid Occlusion Surgery Study (COSS), which evaluated EC–IC in patients with a completely blocked carotid artery. COSS was halted in 2010 when an interim analysis indicated that patients who had bypass surgery had no fewer strokes than patients on medical therapy alone.

HONOLULU—Restoring adequate blood flow to the brain through surgery to bypass a blocked carotid artery may not improve cognitive performance in patients who have had a stroke or transient ischemic attack (TIA), investigators reported at the 2013 International Stroke Conference.

Randolph S. Marshall, MD, Elizabeth K. Harris Professor of Neurology at Columbia University Medical Center in New York City, and colleagues conducted the Randomized Evaluation of Carotid Occlusion and Neurocognition (RECON) study to determine whether bypass surgery could preserve or improve cognition over two years. Patients’ mean age was 57.1. Twenty-five men and 10 women were randomized to optimal medical treatment or optimal medical treatment and extracranial¬–intracranial (EC–IC) bypass. During EC–IC bypass, a surgeon connects a scalp artery outside the skull to a brain artery inside the skull through a small hole, thus bypassing the blocked carotid artery to increase blood flow to the brain.

All patients had had a stroke or TIA caused by a clot and had had cognition problems. Common cognition problems included mild short-term memory loss, poor concentration, and not feeling mentally acute. The most common abnormalities on cognitive testing were needing increased time to complete timed tasks or to perform tasks that required alternating between different types of information.

Of the 35 patients, 28 survived without a subsequent stroke to undergo the two-year cognitive evaluation. Fifteen of these patients were on optimal medical treatment, and 13 were on optimal medical treatment and had had EC–IC bypass. At baseline, patients with the worst blood flow had the worst cognitive problems. Patients who had better blood flow to the brain at baseline, and patients who had a TIA rather than a stroke, had the most cognitive improvement at follow-up. Final results indicated that surgery was no better than medical therapy at preserving or improving cognitive function at two years after treatment initiation.

“One problem that could partly explain the negative results was that only three out of 13 patients in the surgical group actually achieved normal blood flow after the operation,” said Dr. Marshall in a press release. “It’s still quite likely that cognitive impairment due to a low blood flow state represents one of the only reversible types of dementia,” he added. “Besides this bypass operation, there are other ways of achieving better blood flow, both mechanical and pharmacological, so the next direction for this work is to find a treatment that has a better chance of improving blood flow with fewer complications.”

RECON was an ancillary trial of the Carotid Occlusion Surgery Study (COSS), which evaluated EC–IC in patients with a completely blocked carotid artery. COSS was halted in 2010 when an interim analysis indicated that patients who had bypass surgery had no fewer strokes than patients on medical therapy alone.

HONOLULU—Restoring adequate blood flow to the brain through surgery to bypass a blocked carotid artery may not improve cognitive performance in patients who have had a stroke or transient ischemic attack (TIA), investigators reported at the 2013 International Stroke Conference.

Randolph S. Marshall, MD, Elizabeth K. Harris Professor of Neurology at Columbia University Medical Center in New York City, and colleagues conducted the Randomized Evaluation of Carotid Occlusion and Neurocognition (RECON) study to determine whether bypass surgery could preserve or improve cognition over two years. Patients’ mean age was 57.1. Twenty-five men and 10 women were randomized to optimal medical treatment or optimal medical treatment and extracranial¬–intracranial (EC–IC) bypass. During EC–IC bypass, a surgeon connects a scalp artery outside the skull to a brain artery inside the skull through a small hole, thus bypassing the blocked carotid artery to increase blood flow to the brain.

All patients had had a stroke or TIA caused by a clot and had had cognition problems. Common cognition problems included mild short-term memory loss, poor concentration, and not feeling mentally acute. The most common abnormalities on cognitive testing were needing increased time to complete timed tasks or to perform tasks that required alternating between different types of information.

Of the 35 patients, 28 survived without a subsequent stroke to undergo the two-year cognitive evaluation. Fifteen of these patients were on optimal medical treatment, and 13 were on optimal medical treatment and had had EC–IC bypass. At baseline, patients with the worst blood flow had the worst cognitive problems. Patients who had better blood flow to the brain at baseline, and patients who had a TIA rather than a stroke, had the most cognitive improvement at follow-up. Final results indicated that surgery was no better than medical therapy at preserving or improving cognitive function at two years after treatment initiation.

“One problem that could partly explain the negative results was that only three out of 13 patients in the surgical group actually achieved normal blood flow after the operation,” said Dr. Marshall in a press release. “It’s still quite likely that cognitive impairment due to a low blood flow state represents one of the only reversible types of dementia,” he added. “Besides this bypass operation, there are other ways of achieving better blood flow, both mechanical and pharmacological, so the next direction for this work is to find a treatment that has a better chance of improving blood flow with fewer complications.”

RECON was an ancillary trial of the Carotid Occlusion Surgery Study (COSS), which evaluated EC–IC in patients with a completely blocked carotid artery. COSS was halted in 2010 when an interim analysis indicated that patients who had bypass surgery had no fewer strokes than patients on medical therapy alone.