Features October 2011 Issue

Stick with Your Aspirin Therapy to Reduce Heart Attack Risks

New research shows that discontinuation of aspirin can raise the risk of non-fatal heart attack by 60 percent.

You may be tired of taking your daily aspirin, especially if it’s one of several pills you swallow every day. But before you think about stopping your aspirin regimen, consider the results of a recent study that found significant risks associated with discontinuing aspirin therapy.

The study, published in the online edition of BMJ on July 19, found that patients who had been on low-dose aspirin therapy to prevent heart attacks and other cardiac complications faced a 60 percent increase in their risk of non-fatal heart attacks if they stopped taking aspirin.

Cleveland Clinic cardiologist Michael Faulx, MD, says the study supports the advice most cardiologists give their patients. “I thought this was a good ‘big picture’ study that agrees with other studies like it,” he says. “In general, patients with known vascular disease have fewer cardiac events and heart-related deaths than those who stop taking aspirin.”

Dr. Faulx adds that the study does not explain why the risk suddenly rises with aspirin discontinuation, nor can it predict the risk for an individual patient. The study does, however, make a strong case for patients to stick with their aspirin regimen.

Aspirin Protection
Aspirin helps interfere with the clotting action of platelets in the bloodstream. Aspirin binds irreversibly to platelets, which live in your blood for about one week, Dr. Faulx says. “Therefore, your blood isn’t fully ‘sticky’ again until about a week after you stop aspirin or clopidogrel (Plavix),” he adds.

The danger of blood clot formation is especially high when plaque in an artery builds up. When the fatty material bursts, a clot can form, unless an anticoagulant agent is being taken to reduce the risk of platelet aggregation.

The risk of blood clots is also higher in patients who have had coronary stents put in to open up narrowed blood vessels supplying blood to the heart. Stent implantation can trigger the clumping of platelets in response to the presence of a stent, perceived by the body as a foreign object.

“I tell all my patients with intracoronary stents that they are committed to aspirin for life unless they have a major bleeding problem,” Dr. Faulx says. “This is because the stakes are higher in terms of stent thrombosis risk. Similarly, people who have suffered heart attacks or strokes have more at stake than those who have not, simply because these individuals have already demonstrated their potential to form dangerous clots.”

However, Dr. Faulx notes that an “at risk” patient with diabetes but no history of vascular disease and who has major gastrointestinal bleeding concerns is probably better off avoiding aspirin therapy. “Assessing this risk/benefit balance is your doctor’s job, and he or she should review this with you,” he adds.

Quitting Aspirin
Researchers also found that as many as half of the patients who start aspirin therapy wind up stopping on their own. Dr. Faulx says that is not a decision that should be made without careful consideration and consultation with your doctor.

Patients who think they may fare better with alternative medications may not always be happy with the effects or risks of aspirin alternatives. Dr. Faulx also notes that among the reasons why a tried-and-true medication such as aspirin helps protect against heart attacks are its anti-inflammatory effects.

“These effects are missing from drugs like clopidogrel and warfarin (Coumadin),” he says. “The bleeding risk from clopidogrel tends to be greater than aspirin, particularly low-dose aspirin.”

While the study looked at daily aspirin therapy ranging from 75 mg to 300 mg daily, low-dose aspirin is considered around 75 mg to 150 mg, or one baby aspirin and one half a normal adult aspirin.

Dr. Faulx explains that the risks associated with quitting aspirin may be highest in the first few weeks after quitting.

“There is some research to suggest that your body’s clotting ability ‘rebounds’ or overshoots when the aspirin first wears off,” he says. “But the true mechanism for this observation is unknown.”

He adds that an especially critical time to follow your doctor’s advice is the lead-up to surgery. He says quitting aspirin a week or so before surgery, plus the rebound effect, plus the injury to tissue and blood vessels associated with surgery can combine to create a “perfect storm” for clot formation.

Aspirin therapy is no different than any other kind of medication regimen in that concerns about the drug and any side effects should be discussed with your doctor.