New Device May Limit Stroke Damage
Experimental 'Corkscrew' Device May Reverse Stroke Damage
Feb. 5, 2004 -- Several new experimental devices may change the face of stroke intervention by extending the treatment "window" to eight hours or more.
About 700,000 Americans will suffer strokes this year and many of them will be permanently disabled, often because they were unable to get timely treatment with clot-busting drugs. But some scientists are excited by new treatment possibilities on the horizon.
Chief among these new technologies is a tiny corkscrew-shaped device that can be threaded deep into the brain vessels to pull out dangerous blood clots and restore normal blood flow.
With the corkscrew device patients can sometimes regain function with amazing speed. "I've seen movement restored to paralyzed patients on the table," researcher Sidney Starkman, MD, professor of emergency medicine and neurology at the University of California in Los Angeles tells WebMD.
Faster Help on the Way?
Speaking at the 29th International Stroke Conference here, Starkman presented results from two studies of 141 stroke patients. The new technique uses a corkscrew device which is inserted into an artery in the groin and then guided up to the brain, actually restoring blood flow to the brain in 61 or 114 patients.
Currently the only Food and Drug Administration approved treatment for ischemic stroke, the most common type of stroke is the clot-busting drug called tissue plasminogen activator or tPA. An ischemic stroke is caused by a blood clot in an artery of the brain. Blood flow to the brain tissue stops and results in cell death and the devastating disabilities of a stroke. But when tPA is given by standard infusion, the clot-busting drug must be administered within three hours of stroke onset to prevent brain cell death.
However, only about 3% of stroke patients actually receive tPA and "only about one in eight of [those treated] benefit from treatment," says Marc Mayberg, MD, chair of the department of neurosurgery at The Cleveland Clinic Foundation, and chair of the American Stroke Association Stroke Council.
Starkman says that another advantage for mechanical clot retrieval is speed: it takes about two hours to infuse tPA, but pulling a clot out by the device, which is called the Concentric Merci Retrieval System, can take just minutes.
Device Not a 'Cure-All'
Although Starkman is enthusiastic about the device, he says its real advantage might be when it is used in combination with clot-busting drugs. Drugs like tPA carry a significant risk for bleeding in the brain. "This combination approach would allow us to use lower levels of tPA, which would reduce the risk of bleeding," he says. And used together, he says it is likely that the results will be better than either device or clot buster by alone.
But Larry Goldstein, MD, professor of neurology and director of the Duke University Medical Center, says the device is not a cure-all for stroke. "First, you have to be able to see the clot," he says. Neurologists use special brain scans to find clots in the brain. He estimated that only about half of ischemic stroke patients have clots that can be "seen" using this imaging technology.