A new study suggests that some people who take aspirin to beat off heart attacks may not be getting all the benefits they thought they were. Heart attacks are caused by clots. Doctors often recommend daily use of aspirin to help prevent heart attacks.
Aspirin works by blocking the formation of thromboxane A2, a chemical in the body that makes platelets sticky and promotes blood clotting. The study found that as many as 75% of patients showed some resistance to the blood-thinning effects of aspirin. The study found that taking aspirin did not adequately block thromboxane in some people, making them 4 times more likely to die of a heart attack than those in whom aspirin works.
The researchers analyzed urine samples of 5,529 heart patients for a chemical byproduct of thromboxane. The levels of the byproduct varied substantially among the aspirin users but were still lower than they were in patients not taking aspirin at all. Researchers analyzed that aspirin did not adequately block thromboxane in some patients because of an underlying genetic mutation.