Study Finds Mental Gains in a Neck Artery Treatment

By BARNABY J. FEDER - - NY Times

Patients who underwent a minimally invasive procedure to reduce their risk of a stroke by clearing plaque from neck arteries had unexpected gains in memory and mental skills, according to a study that will be presented today at a medical conference in Toronto.

If the results are confirmed by other trials, wider use of the procedure may allow many elderly people to continue to live independently, said Dr. Rodney Raabe, the radiologist who led the research team at the Sacred Heart Medical Center in Spokane, Wash.

The procedure is known as carotid stenting and has been recently developed as an alternative to painful neck surgery, which about 150,000 Americans undergo annually at a cost of some $2 billion. It relies on tiny devices maneuvered through the circulatory system to the carotid arteries in the neck from a small incision in the thigh. Doctors inflate a balloon to push the plaque into the vessel wall and then implant a metal mesh scaffold, or stent, to keep the artery open.

Dr. Raabe's research team had set out hoping to find that stenting reduced stroke risks without damaging mental abilities. While stenting typically improves blood flow to the brain, it also unleashes a temporary shower of microdebris that can disrupt brain functions, occasionally causing fatal strokes or other serious harm.

The team enrolled 100 patients over the last two years to look at whether using a filter to catch most of the debris during the procedure would reduce the disruptions so patients suffered no mental impairment. Two smaller, less rigorous studies had previously suggested that patients might benefit mentally — as have some studies of neck surgery — but Dr. Raabe said he had been skeptical of those reports.

The new data are the strongest yet to suggest that the benefits from the increased blood flow tend to swamp any harm from the debris. Taking memory tests and so-called executive function tests that required them to perform a series of actions to complete a task, patients did better after the procedure than before. Some reported that colors were brighter. On the basis of the first 30 patients given follow-up tests after six months, Dr. Raabe said it was already statistically improbable that the improvements were due to chance.

He added that the gains were particularly striking for patients who had not yet suffered ministrokes or other symptoms of brain impairment but whose arteries were more than 90 percent blocked. Medicare and many private insurers cover neck surgery for such patients, but not stenting.

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