Why do cardiologists prescribe aspirin (acetylsalicylic acid) for patients?

From the Guidelines

Cardiologists prescribe aspirin primarily to prevent blood clots that can cause heart attacks and strokes, with the most recent and highest quality evidence supporting its use in patients at high risk of occlusive vascular events, including those with prior or acute myocardial infarction, as demonstrated by the Antithrombotic Trialists’ Collaboration’s meta-analyses 1. Aspirin works as an antiplatelet medication, preventing platelets from sticking together and forming clots by inhibiting the enzyme cyclooxygenase, which reduces the production of thromboxane A2, a substance that promotes platelet aggregation. The typical dose for cardiovascular prevention is low-dose aspirin (81-100 mg daily), though some patients may be prescribed 325 mg daily depending on their specific condition, with the American College of Cardiology/American Heart Association task force recommending an initial loading dose of 162 to 325 mg of non–enteric-coated aspirin, followed by an 81-mg daily dose to minimize bleeding risk 1. Aspirin is commonly recommended for patients who have already experienced a heart attack, stroke, or have undergone procedures like stent placement or bypass surgery, as well as those with high cardiovascular risk factors, including diabetes, hypertension, and peripheral vascular disease, as outlined in the European Society of Cardiology guidelines 1. However, aspirin therapy carries bleeding risks, particularly gastrointestinal bleeding, so it's not recommended for everyone, and the decision to take aspirin should be individualized based on the patient's cardiovascular risk versus bleeding risk, with patients taking aspirin with food to minimize stomach irritation and never stopping it suddenly without consulting their doctor, as this could trigger a rebound effect increasing clot risk 1. In patients with acute coronary syndromes, aspirin is recommended in combination with other antiplatelet agents, such as clopidogrel, and anticoagulants, such as warfarin or direct oral anticoagulants, with the goal of minimizing the risk of thrombotic events while reducing the risk of bleeding complications 1. Some key points to consider when prescribing aspirin include:

• The dose and duration of aspirin therapy should be individualized based on the patient's specific condition and risk factors.
• Aspirin should be used in combination with other medications, such as antiplatelet agents and anticoagulants, in patients with acute coronary syndromes or those undergoing procedures like stent placement or bypass surgery.
• Patients should be monitored closely for signs of bleeding or other adverse effects, and the decision to continue or discontinue aspirin therapy should be made on a case-by-case basis.
• The use of aspirin in patients with diabetes or other high-risk conditions should be carefully considered, with the goal of minimizing the risk of cardiovascular events while reducing the risk of bleeding complications 1.

From the Research

Aspirin Prescription for Patients

Cardiologists prescribe aspirin (acetylsalicylic acid) for patients due to its benefits in preventing cardiovascular disease. The key reasons include:

• Prevention of cardiovascular events in patients with clinical manifestations of coronary heart disease, such as those with evolving acute myocardial infarction, unstable or stable angina, and those who undergo coronary artery bypass grafting or coronary angioplasty 2
• Reduction of risk in patients with peripheral arterial disease, including those with acute or previous history of ischemic stroke or transient ischemic attack 2
• Benefit in patients without symptoms but at increased risk of a coronary heart disease event (> 1% annual risk) when taken as part of an overall program of lifestyle measures 2

Aspirin Dosage and Side Effects

The prevention benefits of aspirin in heart disease can be achieved with doses as low as 75-150 mg daily 2. However, aspirin use is associated with side effects, including:

• Stomach upsets
• Activation of peptic ulcers
• Increased tendency to bruising
• Allergic reactions
• Increased risk of major gastrointestinal and other bleeding, including intracranial hemorrhage 2, 3, 4, 5

Clinical Use of Aspirin

Aspirin is the most widely used and tested antiplatelet drug in cardiovascular disease, and it is proven to be the cornerstone of antiplatelet therapy in treatment and prevention of cardiovascular disease in clinical trials in various populations 3. The role of aspirin in primary prevention remains uncertain and is still debated, as the absolute risk of vascular complications is the major determinant of the absolute benefit of antiplatelet prophylaxis 4, 5. Recent trials have shown that the recommendation for aspirin use as primary prevention has been downgraded 6, 5.