Women may benefit less from aspirin for the heart

NEW YORK, May 12 (Reuters) Women with heart disease appear to be more likely than men to be resistant the blood-thinning effect of aspirin, according to new study results. However, whether so-called ''aspirin resistance'' affects patients clinically has not yet been determined, Dr Susan S Smyth and colleagues report.

Aspirin works by preventing platelets, the cells that cause blood to clot, from sticking together. However, this effect seems to be diminished in some people.

The original goal of the researchers' study was to see if 50 patients with a prior heart attack while on aspirin therapy were more likely to be aspirin resistant than 50 patients who had coronary heart disease but had not had a heart attack.

Aspirin resistance was determined by measuring the clumping of platelets in blood samples. Fourteen patients were classified as ''biologically aspirin resistant,'' the team reports in the Annals of Pharmacotherapy.

Smyth, from the Gill Heart Institute in Lexington, Kentucky, and colleagues found that aspirin resistance did not differ significantly between those who had had a heart and those who hadn't.

In fact, the only factor that was strongly linked to aspirin resistance was being female, since nine of the 14 people with the condition were women.

However, Smyth and her associates noted that 13 of the 14 aspirin-resistant patients were taking only a baby aspirin daily. When they switched to a regular dose, six were seen to be responsive to aspirin based on the platelet-clumping test.

Nonetheless, until research establishes the clinical significance of their findings, the team does not advocate changes in aspirin dosing based on their small study.

REUTERS SW RK0910