Carotid Bypass Surgery Does Not Improve Cognition After Stroke

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Main Category: Stroke
Article Date: 10 Feb 2013 - 0:00 PST


Patients who have suffered from stroke and receive carotid bypass surgery - which improves blood flow to the brain - see no overall improvement in cognitive performance, researchers informed at The American Stroke Association's International Stroke Conference 2013.

Extracranial-intracranial (EC-IC) bypass surgery involves connecting a scalp artery outside the brain to a brain artery, bypassing the blocked carotid artery, in an effort to restore blood flow to the brain.

The Carotid Occlusion Surgery Study (COSS) was originally carried out to determine the effectiveness of EC-IC in patients with a blocked carotid artery. However, it was suspended early because an interim analysis found that the bypass did not reduce the number of strokes compared to therapy alone.

Following the COSS, an ancillary trial called the Randomized Evaluation of Carptid Occlusion and Neurocognition (RECON) was carried out. The aim of this second trial was to see whether the bypass surgery improved cognition in the patients over a period of two years following the surgery.

The study included 25 men and 10 women with an average age of 57 years. All of the patients experienced cognitive problems due to either a clot-caused stroke or a mini stroke. They were unable to concentrate well and had mild short-term memory loss.

Only 28 of the patients survived and were able to participate throughout the whole study period, 15 of whom only received medical treatment while the other 13 had medical treatment along with EC-IC bypass surgery.

Bypass surgery no better than medical therapy in improving cognitive performance

The results indicated that patients with poor blood flow had the worst cognitive ability. In addition, they found there was no difference in cognitive ability among those who underwent EC-IC bypass surgery versus those who received medical therapy alone.

Randolph S. Marshall, M.D., M.S., lead author of the study, said:

"When patients receive the best medical therapy including statins for cholesterol and medications to control diabetes and high blood pressure cognitive improvement is no different when bypass surgery is added to medical therapy."

The people who experienced the most cognitive improvement were those who did not suffer from a full stroke but only transient ischemic attack (mini-stroke).

Marshall added:

"It's still quite likely that cognitive impairment due to a low blood flow state represents one of the only reversible types of dementia. 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."

The study was funded by The National Institutes of Health, National Institute of Neurological Disorders and Stroke.

Previous research presented at the Canadian Stroke Congress identified that one of the best ways of improving cognitive performance after a stroke is to exercise, which was found to improve language, thinking and memory by up to 50 percent.

Written by Joseph Nordqvist
Copyright: Medical News Today
Not to be reproduced without permission of Medical News Today

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