American Heart Association updates 'mini stroke' guidelines

DALLAS, Nov. 5 -- New blood thinning medications are among the significant medical and surgical advances that have occurred over the past five years for the treatment of "mini-strokes," that have led to updated guidelines that appear in this month's Stroke: Journal of the American Heart Association.

The updated TIA guidelines are aimed at helping physicians better treat patients who've had mini-strokes.

A "mini-stroke" is actually a transient ischemic attack, or TIA, which occurs when a blood clot briefly blocks an artery that supplies blood to the brain. The symptoms -- which may last only a few minutes or several hours -- include weakness or sudden loss of vision. TIAs are strong predictors of future strokes. An individual who has experienced a TIA is about 10 times more likely to suffer a major stroke than someone who has not.

The significant medical and surgical advances over the past five years that led to the updated guidelines are:

• New antiplatelet agents. These "blood thinners" help to prevent blood clots from forming and are an alternative to aspirin for patients who cannot tolerate aspirin or have had a TIA despite aspirin therapy. The new antiplatelet drugs are clopidogrel, which can be used alone, and dipyridamole, which is most effective when used in combination with aspirin.

"The addition of these two new antiplatelet medications offers physicians more options for treating stroke and TIA patients," says Gregory W. Albers, M.D., director of the Stanford Stroke Center, Stanford University Medical Center and associate professor of neurology/neurological sciences at Stanford University, Palo Alto, Calif.

The updated TIA guidelines discuss each of the four antiplatelet agents now available to physicians, their potential side effects, and which patients are appropriate candidates for each of the blood-thinning medications.

Albers says another significant change in the updated guidelines is the lowering of the recommended dosages of aspirin to prevent stroke. "Some experts recommend much higher doses of aspirin therapy to prevent stroke in high-risk patients. Recent studies indicate that aspirin can be just as effective for stroke prevention at lower doses ranging from 50 to 325 milligrams. This means fewer side effects for patients," Albers says.

• Anticoagulants. Recent studies show that anticoagulants, such as warfarin, are better than aspirin for preventing future strokes in patients with atrial fibrillation--a type of irregular heartbeat--who've had a TIA.
• Carotid artery surgery. Many strokes are caused by a blockage in the carotid artery in the neck, which supplies blood to the brain. A procedure called carotid endarterectomy involves the surgical removal of the blockage from the artery. The updated TIA guidelines state that the surgery is beneficial in patients with blockages that obstruct more than half of the blood vessel (50 percent). The previous guidelines recommended carotid endarterectomy for patients with a 70 percent or greater blockage in the carotid artery. However, the surgery appears to be less beneficial for certain populations--the elderly, women and individuals with diabetes, according to recent studies. The updated guidelines recommend that physicians consider age, gender and other issues when determining who would be an appropriate candidate for carotid surgery-- particularly for patients with blockages of 50 to 69 percent.
• Angioplasty and stents. The placement of a small, mesh-like tube called a stent inside the carotid artery, the blood vessel in the neck, to help hold it open and prevent a re-blockage is currently being evaluated as an alternative to carotid artery surgery. The updated guidelines suggest that until the results of more testing are available, stenting for carotid arteries should be viewed as investigational.

The updated guidelines are an important tool for physicians, according to Ralph L. Sacco, M.D., associate chairman of neurology at Columbia University, New York, and a co-author of the updated TIA guidelines. "It's important for physicians to recognize the importance of these new TIA guidelines, and to follow them in order to ensure state-of-the-art treatment for TIAs into the new millennium," he says.

Co-authors of the updated guidelines are Robert G. Hart, M.D.; Helmi L. Lutsep, M.D.; and David W. Newell, M.D.