The American Heart Association (AHA) and American Stoke Association (ASA) are recommending a new stroke treatment—the first in 20 years to earn AHA's strongest endorsement.
The associations are urging doctors to use "stent retrievers" to treat certain patients with strokes caused by a blood clot blocking the large arteries supplying blood to the brain, according to guidelines published in Stroke, an AHA journal.
An endovascular stent retrieval device is small mesh cage that is inserted to an artery in the groin, then threaded through a thin wire tube into a blood vessel until it reaches the blockage. The wire mesh then grabs the clot and is removed when the tube is pulled out.
The guidelines recommend that the procedure only be performed by physicians at comprehensive or primary stroke centers, and only for patients whose clot persists after the standard treatment of tPA, a clot-dissolving drug. tPA fails in about 25% to 50% of cases, in part because some clots are too large for the medication to dissolve, according to William Powers, chair of the group that wrote the guidelines.
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According to AHA and ASA, six clinical trials released over the past eight months have shown that using a stent retrieval device when clots have remained after tPA has significantly decreased patients' risk of disability or death.
The guidelines recommend that doctors use the stent retrievers when patients:
- Do not have a significant disability prior to their current stroke;
- Have a clot blocking a large artery that is providing blood to the brain;
- Are 18 years or older;
- Have an acute, severe stroke;
- Have imaging indicating that more than 50% of the brain on the side of the stroke does not have permanent damage;
- Can receive the treatment within six hours of the onset of a stroke; and
- Received tPA within four and a half hours of the onset of stroke symptoms.
Powers says that researchers do not know the benefit of stent receivers after six hours of a stroke's onset, or for individuals that have not first been treated with tPA. "We think it probably works in some of them but we just don't have the hard evidence" to recommend the treatment, Powers explains.
As a result, the guidelines will not apply to the majority of the more than 800,000 U.S. patients per year who have strokes caused by a blood clot in the brain. According to a study released last year, about 3% to 5% of those who have strokes receive tPA, mostly because the patients do not arrive at hospital EDs within four and a half hours of the onset of stroke symptoms, Lenny Bernstein writes for the Washington Post's "To Your Health" (Bernstein, "To Your Health," Washington Post, 6/29; Marchione, AP/ABC News, 6/29; Thompson, HealthDay/U.S. News & World Report, 6/29; AHA release, 6/29).
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