THURSDAY, May 18 (HealthDay News) -- New European research suggests that combining aspirin with a second drug, dipyridamole, may help stroke survivors ward off a second cardiovascular event better than using aspirin alone.

Both medications act to prevent clotting, and the combination has been available in the United States in a prescription drug, Aggrenox. Current guidelines for what is called "secondary prevention of stroke" recommend aspirin alone, the combination of aspirin and dipyridamole, or a third clot-preventer, clopidogrel (Plavix), depending on individual patient characteristics.

A statement by Dr. Ale Algra, the Dutch neurologist who was the lead author of a report on the European/Australasian Stroke Prevention in Reversible Ischemia Trial (ESPIRIT) published in the May 20 Lancet, made the issue look simple: "The results of ESPIRIT, combined with the results of previous trials, provide sufficient evidence to prefer the combination therapy of aspirin and dipyridamole over aspirin [alone]" for stroke survivors, the researchers said.

Over the more than three years of the study, 13 percent of the 1,363 patients who took the combination had circulatory events such as second strokes, compared to 16 percent of the 1,376 patients who took aspirin alone.

The reduction in risk is "a modest difference but a significant difference," said Dr. Cathy Sila, associate director of the cerebrovascular program at the Cleveland Clinic. "Were always looking for something that eats away at the problem more," she added.

But there are interesting aspects of the study that must be considered when a physician makes a decision for these patients, Sila said. One is the fact that the benefit of the combined therapy became apparent only after about 2.5 years of treatment, she noted.

While the study supports current U.S. guidelines, "I don't think [combined therapy] is going to replace aspirin" for all people who have had strokes or mini-strokes, which are formally called transient ischemic attacks (TIAs), Sila said.

One reason is that the prescribing physician has to consider the source of the clot that caused the stroke, she said. If the cause was atrial fibrillation -- the abnormal heartbeat that promotes clot formation -- the preferred treatment would be warfarin, a clot-preventing drug that is potent but difficult to manage.

If the clot did not originate in the heart, a patient's reaction to dipyrimadole must be considered, Sila said. About a third of the people put on combination therapy in the European trial stopped taking the medication because of side effects, most notably headaches.

Another issue is cost. Sila computed the cost for a month's worth of Aggrenox at $122 and for Plavix as $117. A month's use of aspirin would cost less than $2, she noted.

The study was funded by a variety of European government health agencies, as well as the Council of Singapore.

The final word on secondary prevention is not in, Sila said. Several studies are under way, including one that compares Aggrenox with Plavix.

What is clear is that "the vast majority" of people who have had strokes should be on some kind of clot-preventing medication, Sila said. "It's up to the physician to figure out a way to make these treatments realistic, so we can achieve the benefits of medication," she said.

More information

For more on preventing stroke, head to the American Stroke Association.

SOURCES: Cathy Sila, M.D., associate director, cerebrovascular program, Cleveland Clinic, Cleveland; May 20, 2006, The Lancet

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