Ask Doctor K: Benefits vs. risks of aspirin

DEAR DOCTOR K: I had a heart attack several years ago. I have been taking low-dose aspirin ever since to prevent a second one. Do I need to worry about bleeding risks?

DEAR READER: Aspirin helps prevent repeat heart attacks in two ways. A heart attack occurs when the flow of blood through one of the heart’s arteries is blocked. Without a blood supply, the part of the heart that gets its blood from that artery dies. Most such sudden blockages begin when a cholesterol-filled plaque of atherosclerosis ruptures. Plaques rupture when there is inflammation inside them.

When a plaque ruptures, it spills cholesterol into the blood. This causes platelets in the blood to clump together and form a blood clot. The clot blocks the flow of blood. Aspirin quiets the inflammation within plaques that leads to rupture. Aspirin also prevents platelets in the blood from clumping together and forming clots.

Dozens of studies involving tens of thousands of people have shown that daily low-dose (81 milligram) aspirin reduces the risk for a repeat heart attack or stroke. But aspirin also has risks. For one, it does increase the risk of minor bleeding. Cuts may bleed a little longer than usual. Bruises may be more noticeable.

Aspirin also hinders helpful substances that protect the delicate lining of the stomach. This can lead to stomach upset or bleeding in the stomach and intestines. For both men and women, gastrointestinal bleeding and hemorrhagic (bleeding) stroke are the main risks of aspirin. That’s why the U.S. Preventive Services Task Force recommends low-dose, rather than regular-strength, aspirin to prevent a repeat heart attack. Low-dose aspirin seems to work just as well as higher doses, with fewer bleeding problems.

The risk of bleeding complications rises with age. Aspirin-induced bleeding is also more likely to occur in people who have a history of uncontrolled high blood pressure, ulcers or bleeding problems. The risk is also higher in people who regularly take nonsteroidal anti-inflammatory drugs such as ibuprofen (Advil, Motrin), or the blood thinner warfarin (Coumadin).