Stroke Patients May Not Be Offered Advanced Therapy
Stroke patients who fail the standard stroke treatment using clot-busting drugs may succeed with more advanced therapies that attack blood clots directly in the brain, according to data being presented at the 20th annual International Symposium on Endovascular Therapy (ISET).
"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," said Christopher Zylak, M.D., director of neurointerventional radiology at Sacred Heart Medical Center, Spokane, Wash. "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."
Eighty-three percent of strokes are "ischemic," meaning they are caused by a small clot that blocks an artery in the brain, stopping blood flow, according to the American Stroke Association. (The remaining 17 percent of strokes are "hemorrhagic," and are caused by a leaking or ruptured blood vessel in the brain.) If the clot is not cleared and blood flow restored, permanent damage will result, such as paralysis or death. 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.
Standard therapy at most hospital stroke centers involves placing an IV device in the patient's arm to administer clot-busting drugs, a percentage of which get to the site of the blockage in the brain that is causing the stroke. However, IV treatment must begin within three hours of the onset of stroke, meaning the patient must get to the hospital at the first signs of stroke.
The more advanced IA therapy involves placing a tiny tube, called a catheter, through a nick in the patient's groin and advancing it through the artery all the way to the blockage in the brain. Clot-buster drugs can then be administered directly to the clot to break it up and open up blood flow. Alternatively, a tiny corkscrew-like device can be placed in the clot to pull it out. IA therapy can be performed up to eight hours after the onset of stroke, but is available at far fewer medical centers.
Sacred Heart Medical Center offers both IV and IA therapy. At the center, stroke patients first undergo brain imaging with computed tomography (CT) to determine if the stroke is ischemic or hemorrhagic. If a patient comes to Sacred Heart less than three hours after the onset of an ischemic stroke, he or she will be given IV therapy. If the symptoms don't improve in an hour, IA therapy is administered. If the patient comes to the hospital more than three hours after the beginning of the stroke, IA therapy is used immediately.
Dr. Zylak will report results on a subset of patients who were treated at Sacred Heart from 2004 through 2007: 80 who received IV therapy and 43 who received IA therapy. The latter number includes patients who received IA therapy after failing IV therapy. Success rates of IA therapy -- defined as opening up of the blocked vessel -- were 85.7 percent in 2006 and 83.3 percent in 2007. Although death rates were 30.8 percent in 2006 and 27.8 percent in 2007, they were half the death rates of 50 to 80 percent published in the natural history outcomes of large-vessel strokes.
"Without any question, we definitely were able to help patients who failed IV therapy by providing IA therapy," said Dr. Zylak, who also is an interventional radiologist with Inland Imaging, Spokane. "In the future, for large-vessel clots IA therapy may well be the best direct therapy, bypassing IV therapy."
Many people suffering a stroke don't receive any type of treatment because they don't recognize the signs -- including vision and speech disturbances, paralysis and memory problems -- and therefore don't seek medical care. Immediate medical attention is key because the sooner a stroke is treated, the more likely the 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," said Dr. Zylak. "Treatment therapies today are really 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."