Wednesday, January 23, 2008
WEDESDAY, Jan. 23 (HealthDay News) -- Therapies that attack blood clots directly in the brain may benefit ischemic stroke patients who don't respond to the standard treatment using clot-busting drugs.
So says a U.S. study that was to have been presented Tuesday at the 20th annual International Symposium on Endovascular Therapy, in Hollywood, Fla.
Ischemic strokes -- which account for about 83 percent of strokes -- occur when a small clot blocks an artery in the brain and halts blood flow, according to the American Stroke Association. If the clot isn't cleared and blood flow restored, the patient will suffer permanent brain damage or death.
"Often patients who fail to improve with standard intravenous (IV) stroke therapy aren't given the chance to succeed with more advanced intra-arterial (IA) therapy, because it's thought that it won't work if IV therapy didn't, and that it will increase the risk of bleeding in the brain," study author Dr. Christopher Zylak, director of neurointerventional radiology at Sacred Heart Medical Center in Spokane, Wash., said in a prepared statement. "Our data suggest that IA therapy can be highly successful even when IV therapy doesn't work, and that the risk of bleeding is no different between the two therapies."
In IV therapy, clot-busting drugs are delivered through an intravenous device in the patient's arm. IV treatment must begin within three hours of the onset of stroke, which means patients must get to the hospital at the first signs of stroke.
IA therapy involves placing a catheter through a small incision in the patient's groin and moving the catheter through an artery all the way to the site of the blockage in the patient's brain. This enables direct delivery of clot-busting drugs to the area. Doctors also can use the catheter to insert a tiny corkscrew-like device to remove the clot.
In this study, the researchers compared 80 patients who received IV therapy and 43 patients who received IA therapy at Sacred Heart from 2004 through 2007. Some of the patients who received IA therapy had not responded to IV therapy.
Success rates of IA therapy (defined as opening up of the blocked blood vessel) were 85.7 percent in 2006 and 83.3 percent in 2007. Death rates among patients who received IA therapy were 30.8 percent in 2006 and 27.8 percent in 2007. That's half the 50 percent to 80 percent death rates published in the "natural history outcomes" of large-vessel strokes, the study authors said.
"Without any question, we definitely were able to help patients who failed IV therapy by providing IA therapy," Zylak said. "In the future, for large-vessel clots, IA therapy may well be the best direct therapy, bypassing IV therapy."
He noted that many stroke victims don't receive any treatment, because they don't recognize the signs (such as vision and speech problems, paralysis, and memory difficulties) and don't seek medical care. The sooner a stroke is treated, the more likely treatment will be successful.
"Overall, we are under-treating stroke. There are many patients who could benefit from stroke treatment who aren't getting it for various reasons," Zylak said. "Treatment therapies today are getting dramatic results. If a medical center doesn't offer the more advanced IA therapy, the patient can be taken by helicopter to a center that performs the therapy, even if IV therapy wasn't successful."
Stroke is the third leading cause of death in the United States, killing about 160,000 people a year, according to the National Stroke Association. About 750,000 people suffer from stroke annually.
The Washington University School of Medicine has more about ischemic stroke.
SOURCE: InternationalSymposium on Endovascular Therapy, news release, Jan. 22, 2008