Findings from a University of Maryland study presented at a national meeting
A daily dose of aspirin reduces the risk of a heart attack in 75 percent of people with heart disease, but in about 25 percent of patients using it, aspirin offers no protection. Researchers at the University of Maryland Medical Center in Baltimore now think they know why some of the people who take aspirin are not protected. Their study, presented at the 73rd Scientific Sessions of the American Heart Association in New Orleans on November 14, shows that in those patients, high cholesterol is hindering the effectiveness of the aspirin.
Aspirin, which reduces the clumping or aggregation of blood platelets, has been proven to reduce the risk of a heart attack by 20 to 30 percent, when taken daily. However, in the University of Maryland study, 60 percent of patients with cholesterol levels above 220 mg/dL still had platelet aggregation, in spite of daily aspirin doses, putting them at increased risk of a heart attack.
"We know that aspirin protects against heart disease," says Michael Miller, M.D., F.A.C.C., director of the Center for Preventive Cardiology at the University of Maryland Medical Center and associate professor of Medicine at the University of Maryland School of Medicine. "So we prescribe aspirin for our patients, but we don't measure the effectiveness. This study shows that aspirin may not always work, especially in people with high cholesterol. These people remain at increased risk."
For the study, blood samples from 63 heart disease patients who had been taking 325 mg of aspirin daily for at least thirty days, were tested to see whether the blood platelets clumped together when a special agent was introduced. The test showed that aspirin prevented clumping in 41 patients but in 20 others there was no response. Of the patients with high cholesterol (above 220mg.dL), 60 percent were not helped by the aspir
Contact: Barbara Crawford
University of Maryland Medical Center