Device mechanically removes brain blood clots
An FDA-approved device, which is threaded into the brain’s arteries, can safely retrieve blood clots and open large vessels that become blocked and lead to stroke, research indicates.
Each year, about 700,000 Americans suffer a stroke and 88 percent of those strokes are caused by a blood clot that blocks the blood supply to the brain—so called ischemic stroke.
Stroke caused by occlusion of large brain blood vessels (greater than 1.5 mm in size) is a particularly “mortal form of stroke,” Dr. Wade S. Smith from the University of California, San Francisco noted in comments to Reuters Health.
Many people with these types of stroke are ineligible for commonly used clot-busting drugs.
The so-called Merci Retriever “offers an option for treating these patients who otherwise have no alternative,” Wade said.
The device is inserted into an artery in the groin, and then guided via standard angiography into the brain until it reaches the blood clot. Once the device “captures” the blood clot, the device and clot are withdrawn into a larger catheter with a balloon. During the evacuation process, the balloon is briefly inflated to momentarily stop blood flow so the clots can be safely removed.
Smith and colleagues tested the safety and efficacy of the Merci Retriever to open blocked intracranial large vessels within 8 hours of the onset of stroke symptoms in a group of patients who were ineligible for clot-busting drugs.
In the July issue of Stroke: Journal of the American Heart Association, the investigators report that blood flow was restored in 48 percent (68 of 141) of patients in whom the device was employed.
Successful restoration of blood flow was associated with good neurological outcomes and a lower incidence of death, compared with unsuccessful restoration of blood flow, the authors report.
Complications occurred in about 7 percent of patients, which Dr. Thomas A. Tomsick from the University of Cincinnati Hospital in Ohio contends in an editorial is “probably acceptable for patients with large deficits and poor predictable outcomes.”
“Certainly,” Tomsick concludes, “we have seen the rosy dawning of a new day in ischemic stroke therapy study. However, the Merci device should be viewed as a stop along the path and not the end of the journey itself,” he writes.
Technical improvements to the device are being made and the device will be studied further in upcoming trials, Tomsick points out in his commentary.
SOURCE: Stroke July 2005.
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