Ischemic strokes are caused by a blood clot that blocks blood supply to the brain. Each year, about 700,000 Americans suffer a stroke and 88 percent of those strokes are ischemic, according to the American Stroke Association.
Blood clots causing stroke can be dissolved using the FDA-approved clot-busting drug tissue plasminogen activator (tPA) as standard therapy. But, it must be initiated intravenously within three hours (the earlier the better) of stroke onset to be effective.
Moreover, it "typically takes one to two hours for tPA to dissolve a clot and open a vessel, if at all," said Sidney Starkman, M.D., professor of emergency medicine and neurology at the University of California, Los Angeles and co-director of the UCLA Stroke Center.
The investigational device, the Concentric MERCI Retrieval System, restored blood flow in 61 of 114 patients (54 percent) in Phase I and II of the Mechanical Embolus Removal in Cerebral Ischemia (MERCI I /II) trials, which studied patients up to eight hours after initial stroke symptoms who were not eligible for standard tPA therapy, said principal investigator Starkman.
Restoring blood flow in these trials reversed paralysis and other stroke symptoms, Starkman said.
"How often do we get a chance to reverse a patient's stroke on the table? We have had patients completely paralyzed on one side of their body, who were made normal almost instantaneously when the clot was retrieved," he said.
Of the 61 patients whose arteries were unblocked with the device, "23 have no disability or have minor disability, such as hand writing problems," Starkman said.
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Contact: Carole Bullock
carole.bullock@heart.org
214-706-1279
American Heart Association
5-Feb-2004