Patient information: Aspirin and cardiovascular disease

ASPIRIN AND HEART DISEASE OVERVIEW

Aspirin is a nonsteroidal antiinflammatory drug (NSAID) that has been used at moderate to high doses to decrease pain and reduce swelling. More recently, low dose aspirin has been used to treat and prevent cardiovascular disease (CVD).

Cardiovascular disease includes conditions such as heart attack, stroke, and peripheral artery disease (poor circulation) in the legs; these conditions cause more than 900,000 deaths each year in the United States alone.

Many large trials have shown that aspirin has benefits for the following groups:

• Virtually all people who have had a heart attack, stroke, or peripheral artery disease, as well as angina, stents, or bypass surgery
• Men and women who have no signs or symptoms but have an increased risk of a first heart attack (eg, due to diabetes or other risk factors)

However, the benefits of aspirin must be weighed against its possible side effects. People with a higher risk of heart attack have a greater potential for benefit. Thus, it is important to discuss the overall risk of cardiovascular disease with a healthcare provider to determine if aspirin could be of benefit.

ACTIONS OF ASPIRIN

Aspirin inhibits the clumping of platelets (even in low doses), has pain killing effects (in medium doses), and has antiinflammatory effects (in high doses).

Platelets are tiny cell fragments circulating in the blood that have a role in blood clotting. Under normal circumstances, platelets clump together and help form blood clots that stop bleeding. However, in coronary heart disease, platelets clump together in narrowed arteries, which leads to the development of a clot within the artery; the platelet "plug" itself and/or the clot that forms can block blood flow (figure 1).

This blockage can have significant consequences. When the arteries that supply blood to the brain are blocked, the supply of oxygen to the brain is decreased. The consequences of this depend upon the duration and the extent to which blood flow is cut off.

• When the arteries that supply blood and oxygen to the heart are blocked briefly, the result is an episode of chest pain, called angina. A blockage that is of longer duration can result in a heart attack (also called myocardial infarction).
• In the brain, when the blockage is brief, the result is a transient ischemic attack (TIA), and when the blockage is longer, the result is an ischemic stroke. (See "Patient information: Stroke symptoms and diagnosis".)

BENEFITS OF ASPIRIN

The benefits of aspirin have been studied in a wide range of patients, including the groups discussed below.

Prevention of heart attack or stroke — Several large trials, primarily among men, have shown that aspirin can prevent a first heart attack in people who have no signs or symptoms of cardiovascular disease (this is called primary prevention). However, these trials could not detect the effects of aspirin on the risk of stroke and death related to cardiovascular disease. In one trial of women, aspirin reduced the risk of a first stroke and also decreased the risk of a first heart attack among those age 65 and over [1].

However, the risk of a first heart attack or stroke in healthy men and women is quite low. As a result, the benefit of reducing the risk of a first heart attack must be weighed against potential risks, such as gastrointestinal bleeding and other side effects. (See 'Side effects of aspirin' below.)

Expert groups recommend aspirin to prevent heart attack or stroke for healthy men and women when the benefits outweigh the risks; this includes people with a 10-year risk of a coronary event of at least 6 to 10 percent. The 10-year risk can be calculated here for women (calculator 1) and for men (calculator 2).

For many people, the benefit of aspirin (prevention of heart attacks or strokes) is similar to the risk of harm (gastrointestinal bleeding). Thus, it is important to discuss the risks and benefit of aspirin in your situation with your healthcare provider.

The recommended daily dose of aspirin for prevention of heart attack and stroke is between 75 and 100 mg.

During a heart attack — Aspirin can be life-saving for people who are actively having a heart attack. Health care providers recommend that anyone who believes they may be having a heart attack immediately take 162 to 325 mg of aspirin (one half to one whole adult aspirin tablet). (See "Patient information: Heart attack".)

After coronary events — Aspirin is recommended for people who have a history of the following:

• Heart attack
• Stable or unstable angina
• Coronary bypass graft surgery or percutaneous coronary intervention (angioplasty)

(See "Patient information: Heart attack recovery" and "Patient information: Recovery after coronary artery bypass graft surgery (CABG)" and "Patient information: Heart stents and angioplasty".)

Most healthcare providers recommend that people in this group take between 75 and 100 mg of aspirin daily.

During and after stroke — Aspirin has benefits in people who are having or have recently had an ischemic stroke or transient ischemic attack (TIA). The recommended dose for this group is 81 to 325 mg per day. (See "Patient information: Ischemic stroke treatment" and "Patient information: Transient ischemic attack".)

Aspirin plus clopidogrel — Another antiplatelet medication (clopidogrel, Plavix®) may be recommended, in addition to aspirin, to further reduce the risk of future heart attacks and strokes. This may be suggested for people with a high risk of future cardiovascular events, including people with a prior heart attack, ischemic stroke, or symptomatic peripheral artery disease (also called claudication). (See "Patient information: Claudication (peripheral arterial disease)".)

SIDE EFFECTS OF ASPIRIN

Aspirin can have a significant benefit for people with a wide range of blockages in the heart, brain, or peripheral arteries, as well as those without prior events but who have a sufficiently high risk. However, aspirin has two main side effects: it can cause stomach upset (nausea, vomiting, heartburn, stomach pain, or ulcers) and it can increase bleeding.

Stomach upset — In one large study, approximately 4 percent of all people who took 300 mg of aspirin daily for 5 years noted stomach upset. Signs and symptoms of ulcer were far less common, although the risk of ulcers (particularly bleeding ulcers) is increased in the following settings:

• Increasing age, particularly >60 years
• Higher doses of aspirin
• Long duration of aspirin use
• A past history of gastrointestinal complications from aspirin or other NSAIDs (ibuprofen or naprosyn)
• A past history of ulcers (see "Patient information: Peptic ulcer disease")
• Current use of steroids (eg, prednisone), anticoagulants (such as warfarin), or other NSAIDs

To help prevent stomach upset, aspirin should be taken with food. People with a history of ulcers or stomach upset while taking aspirin or other NSAIDs should talk with a healthcare provider before starting; several recommendations can be made, depending upon the particular circumstances:

• The dose may be reduced
• An enteric-coated (EC) or buffered formulation may be recommended
• A medication may be given to reduce stomach acid
• Testing for a microorganism called H. pylori, which can cause ulcers, may be done (see "Patient information: Helicobacter pylori infection and treatment")

For patients who cannot tolerate aspirin, other antiplatelet medications (clopidogrel [Plavix®] or ticlopidine [Ticlid®]) are available. In special cases, an oral anticoagulant (blood-thinning) drug, such as warfarin (Coumadin®), may be recommended in addition to or as an alternative to aspirin. However, the risks of bleeding are further increased when aspirin and an anticoagulant are combined. (See "Patient information: Warfarin (Coumadin®)".)

Bleeding — Individuals who take aspirin regularly may bleed more than normal after a cut or a nose-bleed. This type of bleeding usually causes no significant problems. Of bigger concern is when bleeding occurs in other areas, most commonly in the gastrointestinal tract (such as a bleeding ulcer), or extremely rarely, in the brain (hemorrhagic stroke). For these reasons, the benefits of aspirin must be weighed against the risks.

Because the effects of aspirin on bleeding last for about a week, it is important to notify a healthcare provider or dentist about aspirin use before any surgical procedure. In most cases, aspirin should be stopped 7 to 10 days before a scheduled surgery.

Interaction with ibuprofen — As mentioned above, taking aspirin and another NSAID (such as ibuprofen) at the same time can increase the likelihood of stomach upset. There is also some evidence that therapy with ibuprofen can interfere with the ability of aspirin to stop platelets from sticking together. For these reasons it seems prudent to take aspirin at least two hours before ibuprofen.

There is also some evidence that therapy with ibuprofen can interfere with the protective effect of aspirin on cardiovascular disease. Patients should speak to a healthcare provider about this interaction if they require long-term ibuprofen therapy.

IS ASPIRIN RIGHT FOR ME?

You and your healthcare provider must balance the benefits of aspirin against the potential risks. As general rules:

• Aspirin has a clear benefit in people with a current or past history of heart attack, angina, ischemic stroke, transient ischemic attack, peripheral artery disease (claudication), as well as people with a 10-year risk of having a coronary event of at least 6 to 10 percent. The 10-year risk can be calculated here for women (calculator 1) and for men (calculator 2).
• Aspirin is likely to have a benefit in people with a moderate to high risk of heart attack or ischemic stroke (stroke caused by blockage of arteries that supply blood to the brain).
• The benefits of aspirin may not outweigh the risks in people who have a low risk of heart attack or ischemic stroke.

WHERE TO GET MORE INFORMATION

Your healthcare provider is the best source of information for questions and concerns related to your medical problem. Because no two people are exactly alike and recommendations can vary from one person to another, it is important to seek guidance from a provider who is familiar with your individual situation.

This discussion will be updated as needed every four months on our web site (www.uptodate.com/patients). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information.

Some of the most pertinent include:

Patient Level Information:
Patient information: Stroke symptoms and diagnosis
Patient information: Heart attack
Patient information: Heart attack recovery
Patient information: Recovery after coronary artery bypass graft surgery (CABG)
Patient information: Heart stents and angioplasty
Patient information: Ischemic stroke treatment
Patient information: Transient ischemic attack
Patient information: Claudication (peripheral arterial disease)
Patient information: Peptic ulcer disease
Patient information: Helicobacter pylori infection and treatment
Patient information: Warfarin (Coumadin®)

Professional Level Information:
Aspirin: Efficacy and toxicity in rheumatic and other disorders
Benefits and risks of aspirin in secondary and primary prevention of cardiovascular disease
Primary prevention of coronary heart disease and stroke
Secondary prevention of cardiovascular disease: Risk factor reduction

A number of web sites have information about medical problems and treatments, although it can be difficult to know which sites are reputable. Information provided by the National Institutes of Health, national medical societies and some other well-established organizations are often reliable sources of information, although the frequency with which they are updated is variable.

• National Library of Medicine

      (www.nlm.nih.gov/medlineplus/healthtopics.html)

• National Heart, Lung, and Blood Institute

      (www.nhlbi.nih.gov/)

• American Heart Association

      (www.americanheart.org)

• The National Coalition for Women with Heart Disease

      (www.womenheart.org/)

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