DALLAS, Oct. 21 - If more people would take an aspirin when they experience chest pain or other symptoms of a severe heart attack, 5,000 to 10,000 lives could be saved in the United States each year, according to an American Heart Association scientific statement published today in the association's journal Circulation.
"There is clear and conclusive evidence of the benefits of aspirin," says Charles Hennekens, M.D., one of three internationally recognized medical leaders on heart disease and stroke who authored the statement titled, "Aspirin as a Therapeutic Agent in Cardiovascular Disease."
"It doesn't matter what brand, just as long as aspirin is used," says Hennekens, chief of preventive medicine at Brigham and Women's Hospital and professor of medicine at Harvard Medical School.
Individuals undergoing a heart attack should take a full tablet (325 milligrams) of aspirin to obtain a "rapid clinical effect," he adds. For those who have had a heart attack and want to prevent another one, "it appears that 50 to 100 milligrams a day or a commercial baby aspirin is sufficient." Aspirin prevents blood platelets from sticking together and forming blood clot masses. By blocking blood vessels, these clots can cause heart attacks and strokes.
The American Heart Association issued the statement, also authored by Mark L. Dyken, M.D., and Valentin Fuster, M.D., to guide physicians on the use of aspirin in the treatment and prevention of cardiovascular disease, the nation's No. 1 killer. It also encourages more doctors to recommend aspirin to patients whom research studies have shown could benefit from this relatively inexpensive over-the-counter drug.
The association's statement calls for a wider use of aspirin than does the Food and Drug Administration. While the FDA has approved package labeling that points out that aspirin can help prevent another heart attack in individuals who have already survived one, the AHA recommends that aspirin be taken by anyone with atherosclerosis, regardless of whether he or she has had a heart attack. Atherosclerosis is the disease process that creates the obstructions in the blood vessels that can impair blood flow to the heart and brain, thus causing a heart attack or stroke. Blood vessels in the limbs, as well as to the heart and brain, are vulnerable to atherosclerosis.
Along with several other health organizations, the AHA has asked the FDA to expand its approved uses of aspirin.
Two studies in the past decade have revealed that 23 to 39 percent of heart attack survivors did not receive aspirin, despite its proven benefits. "We have a challenge to increase the use of aspirin in individuals having a heart attack as well as those who have a wide range of blood vessel, or vascular, diseases," says Hennekens.
The American Heart Association recommends that aspirin be taken when a heart attack occurs and to prevent repeat heart attack in survivors. Since heart attack survivors are at risk for stroke, taking an aspirin daily also can lower risk for suffering a "brain attack," the No. 1 cause of major disability in the United States.
Research studies have not clearly demonstrated aspirin's value in preventing heart attack and stroke in healthy people without cardiovascular disease. "Additional data are needed for complete assessment of aspirin's benefit-to-risk ratio in apparently healthy persons," says Hennekens.
In deciding whether to recommend aspirin to a patient, physicians should consider the patient's risk for cardiovascular disease, the benefits of aspirin and side effects. However, no one should regard aspirin as a substitute for a heart-healthy lifestyle that includes a low saturated-fat diet, regular physical activity and no cigarette smoking.
"Unfortunately in the United States people would rather pop a pill, than change their unhealthy lifestyles," says Hennekens. "Individuals should check with their doctors to determine whether they are candidates for aspirin and the dose they should take," he says. "Aspirin has the best benefit-to-risk ratio as well as benefit-to-cost ratio of any drug therapy for heart disease."
The American Heart Association does recommend that people who have not suffered a heart attack or stroke but who have experienced repeated episodes of unstable chest pain or mini-strokes (transient ischemic attacks) should take aspirin to reduce their risk for having a heart attack or stroke.
Individuals whose coronary arteries are obstructed by atherosclerosis and who undergo angioplasty and coronary bypass surgery to restore blood flow to the heart also should take aspirin, according to the statement.
In writing the scientific statement, Drs. Hennekens, Dyken and Fuster reviewed studies on the role of aspirin therapy. One such study, the Antiplatelet Trial Collaboration overview, which analyzed results of randomized trials of therapy to prevent platelets from accumulating in 54,000 individuals who were at high risk for heart disease, found aspirin therapy reduced by one-fourth the risk of subsequent non-fatal heart attacks and strokes.
Other studies, comparing other antiplatelet agents to aspirin showed that use of ticlopidine resulted in a 21 percent decrease in stroke over aspirin at three years. However, ticlopidine is more expensive and causes more side effects than aspirin.
Another study showed that clopidogrel used in people with heart attack, stroke and peripheral vascular disease produced a slightly lower rate of death with no major differences in side effects than aspirin.
But the use of aspirin to prevent heart or stroke in those who are healthy remains less clear. In the U.S. Physician's Health Study, 22,071 physicians were given an alternate day dose of 325 milligrams of aspirin, resulting in a 44 percent reduction in the risk of first heart attack.
The findings for stroke and overall heart and stroke death rates were inconclusive, but raised the possibility of small increased risk of stroke caused by bleeding in the brain, says Hennekens.
A British trial among male physicians found no significant effects of aspirin, but the trial had only one-fourth the number of physicians as the U.S. trial. Combined, the two trials report a 32 percent reduction in the risk of heart attack by taking aspirin.
An ongoing trial of low dose 50 milligrams aspirin in 40,000 U.S. female health-care professionals -- the Women's Health Study -- will provide further information to develop a rational policy for recommending aspirin use in healthy people to prevent first heart attacks.
Dyken is professor of neurology, Indiana University; and Fuster, president-elect of the AHA, is professor of medicine, Mount Sinai Medical Center.