Heart attacks and strokes often occur when a blood clot suddenly forms within one of the arteries that supply oxygen to the heart or brain. These abnormal blood clots generally occur when a plaque ruptures in the wall of an artery. The clot can obstruct the flow of blood, which produces damage to the heart (a heart attack) or brain (a stroke).
Aspirin can inhibit the formation of these dangerous blood clots by interfering with the action of blood platelets, and thus can help to prevent heart attacks and strokes.
When Can Aspirin Be Useful?
1) Aspirin can be life-saving in people who are having acute coronary syndromes. Anyone who thinks they are having a heart attack should take 162 or 325 mg of aspirin immediately (which is one-half or a whole adult aspirin tablet).2) Aspirin is strongly recommended in people who have had prior heart attacks, have angina, have received angioplasty or stents, or who have had coronary artery bypass surgery. In these individuals, between 75 and 100 mg of aspirin a day can help prevent further heart attacks.
3) Aspirin is recommended in many (but not all) people who have had recent strokes or a transient ischemic attack (TIA, or "mini-strokes"). Some strokes are caused primarily by bleeding into the brain, instead of by blood clots within arteries, and aspirin is generally not recommended for that kind of stroke. If you have had a stroke or a TIA, you should talk to your doctor about whether aspirin would be of benefit to you.
4) Daily aspirin (75 - 100 mg) can help prevent heart attacks in people who have a significantly increased risk of coronary artery disease, but who have never had either a heart attack or angina. However, in these people, aspirin should be used only if their risk of having a cardiovascular event is relatively high (a 10-year risk of at least 6 - 10%), and the risk of side effects is considered low (see the section on Side Effects, below). Recent evidence suggests that in most people in this category, the bleeding risks associated with taking prophylactic aspirin outweigh the benefits. If you have never had angina, heart attack, or stroke, then before starting on daily aspirin you should discuss with your doctor whether prophylactic aspirin would be a good idea.
What About Diabetics?
Diabetics who have had heart attacks, angina or stroke should take aspirin just like non-diabetics who have had these cardiovascular events. And until recently, daily prophylactic aspirin was also strongly recommended for most diabetics over the age of 40, even if they had no history of cardiovascular disease. But this recommendation has now changed.Based on information from recent clinical trials, the American Diabetic Association, the American Heart Association, and the American College of Cardiology recommend prophylactic low-dose aspirin (75 - 162 mg/day) ONLY for diabetic men over the age of 50, and diabetic women over the age of 60, who have at least one additional risk factor for cardiovascular disease (in addition to diabetes), such as a strong family history of cardiovascular disease, smoking, increased blood lipids, or high blood pressure.
This more conservative recommendation for diabetics is related to new evidence that gastrointestinal bleeding with aspirin may be more common in diabetics than in non-diabetics.
What Are The Side Effects of Aspirin?
The chief side effects of aspirin are stomach upset and bleeding - nose bleeds, gastrointestinal bleeding, and bleeding in the brain (hemorrhagic strokes) can occur. While life-threatening bleeding is pretty uncommon, it does occur. So anyone with an increased risk of bleeding (such as a history of peptic ulcers or of hemorrhagic stroke) should try to avoid aspirin.Bottom Line
In the right people, aspirin can be a major help in preventing serious cardiovascular events, such as heart attack and stroke. But because of aspirin's side effects, you should take it only if the benefits outweigh the risks. Be sure to discuss this issue with your doctor before starting to take aspirin for heart attack and stroke prevention.Sources:
Seshasai SRK, Wijesuriya S, Sivakumaran R, et al. Effect of aspirin on vascular and nonvascular outcomes: meta-analysis of randomized controlled trials. Arch Intern Med 2012; DOI:10.1001/archinternmed.2011.628.
Pignone M, Alberts MJ, Colwell JA, et al. Aspirin for primary prevention of cardiovascular disease in people with diabetes. Circulation 2010; DOI:10.1161/CIR.0b013e3181e3b133.
Hennekens, CH, Dyken, ML, Fuster, V. Aspirin as a therapeutic agent in cardiovascular disease. A statement for healthcare professionals from the American Heart Association. Circulation 1997; 96:2751.
