From San Francisco, at the International Stroke Conference
The notion that some people are impervious to the blood-thinning effects of aspirin has been debated for more than 15 years. A meta-analysis of 17 studies now bolsters the evidence for "aspirin resistance" and indicates that the trait increases vulnerability to stroke and heart attack, heightens a person's risk of dying, and diminishes the effects of another commonly used blood thinner.
In the studies reviewed, out of 2,367 people with a history of heart problems or stroke, 618 had a blood-clotting ability that routinely overpowered aspirin's anticlotting effects.
About 33 percent of these aspirin-resistant people experienced a stroke, heart attack, or another vascular ailment during the course of the studies. In contrast, only 15 percent of the aspirin-sensitive people experienced any of these problems, says cardiac surgeon George Krasopoulos of the Royal Brompton Hospital in London.