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New hope for stroke victims
Friday, February 05, 1999 By Anita Srikameswaran, Post-Gazette Staff Writer
One of the first things doctors want to know from a person having a stroke is, how long ago did the symptoms start? Until now, the best answer was "less than three hours ago."
Clot-busting drugs such as TPA must be given within three hours of the onset of stroke symptoms to minimize the damage caused by lack of oxygen to brain tissue.
Now, a large trial has shown that a new drug, prourokinase, keeps that window of opportunity open for six hours and is more effective at dissolving blood clots in the brain.
The study findings were presented yesterday at the American Heart Association's stroke conference in Nashville, Tenn. Investigators from the Cleveland Clinic led the multicenter trial of 51 sites across North America, which ran from 1996 until last August.
"This is the first treatment for stroke ever been shown to be effective as far out as six hours," said Dr. Lawrence Wechsler, director of the stroke institute at the University of Pittsburgh Medical Center, which enrolled 10 patients in the trial. "It's going to greatly increase the number of people with stroke to whom we can give acute stroke therapy."
Nearly 200 patients whose stroke symptoms had started within the previous six hours and had a blockage in a blood vessel at the base of the brain, called the middle cerebral artery, or its branches, were distributed into two groups. One group received the prourokinase plus heparin, a blood thinner, while the other received heparin alone.
Patients who got prourokinase were 60 percent more likely to have suffered slight or no neurological complications 90 days after the stroke compared to those who were not treated with the drug.
Unlike conventional medications like TPA, prourokinase is delivered into the clot, Wechsler said.
"This was done with a catheter that was inserted from a blood vessel in the groin, passed up the arterial circulation, and right smack into the clot itself at the base of the brain," he explained. The heparin is given intravenously.
Angiograms, which provide images of blood flow, were done before and after the procedure and provided data on the clot's location and severity, as well as whether it had dissolved.
Almost 70 percent of the clots were opened, Wechsler said. Previous research has shown that TPA dissolves 30 to 40 percent of clots.
"If getting rid of the clot is what gets people better, and we think that's likely, then this is a much more powerful and effective way of doing that than TPA," he said.
Early stroke signs include transient loss of vision, weakness or numbness on one side, sudden severe headache and loss of balance.
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