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.
Furthermore, in the past few years evidence has accumulated suggesting that long-term low-dose aspirin therapy may reduce the risk of dying from cancer. The combination of cardiovascular risk reduction and cancer risk reduction makes low-dose aspirin a potentially attractive form of preventive medicine - if side effects can be avoided.
What Are The Side Effects of Aspirin?The potential benefits of aspirin must always be weighed against the potential side effects. 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.
When Can Aspirin Be Useful In Reducing Cardiac Risk?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. In these people, aspirin should be strongly considered 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). The higher the risk of cardiovascular disease, the greater the potential benefit of aspirin; the higher the risk of bleeding complications, the lower the potential benefit of aspirin.
Accordingly, most authorities recommend that, for people who do not have cardiovascular disease yet, the decision on using prophylactic aspirin should be individualized. In other words, if you have no cardiovascular disease but have elevated risk, you should discuss 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 About Reducing the Risk of Cancer?In recent years, several studies have suggested that taking daily low-dose aspirin over a long term (at least 5 years) is associated with a reduced risk of dying from cancer, particularly colon cancer and lymphoma. The potential for aspirin to reduce cancer risk is leading to (yet another) re-evaluation of the general recommendations on prophylactic aspirin therapy. For instance, largely because of the combined cardiovascular and cancer benefits of low-dose aspirin, in 2012 the American College of Chest Physicians (ACCP) recommended that virtually everyone over the age of 50 should take low-dose aspirin - unless they have an unusually high risk of bleeding.
While the position of the ACCP may well end up being adopted by other expert groups, currently the ACCP is the only specialty organization which has jumped to this sweeping recommendation. Other specialty organizations and expert panels (such as the United States Preventive Services Task Force) still urge caution (because of the risk of bleeding), and strongly recommend that patients and their doctors decide on an individual basis whether prophylactic aspirin is a good idea.
Bottom LineIn the right people, aspirin can be a major help in preventing serious cardiovascular events such as heart attack and stroke, and it may reduce the risk of dying from some types of cancer. But because of aspirin's side effects, you should take it only if the likely benefits outweigh the potential risks. This is still an issue you ought to discuss with your own doctor.
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