Indications

• acutely, should be considered for all patients with suspected myocardial infarction, unstable angina, or a history of myocardial infarction, angina, stroke, transient ischaemic attack, arterial bypass surgery, or angioplasty
  
  
• reduction of risk of thromboembolism
  
  
• regimen is 75-150mg/day is as effective as higher aspirin doses (1)

The Antithrombotic Trialists' Collaboration meta-analysis (1) showed that aspirin (or another antiplatelet drug) prevents serious vascular events in a wide range of high-risk patients, including people with previous MI, acute MI, prevous stroke or TIA, acute stroke, stable angina, intermittent claudication and - if oral anticoagulants are unsuitable - atrial fibrillation. A commentary on the meta-analysis (2) states that..'the documented effects of antiplatelet agents accross a wide range of patient groups suggests that low dose aspirin should be given routinely to patients at high or intermediate risk for cardiovascular events (above 2% per year).'

Reference:

1. Antithrombotic Trialists' Collaboration (2002). Collaborative meta-analysis of randomised trials of antiplatelet therapy for prevention of death, myocardial infarction, and stroke in high risk patients. BMJ, 324, 71-86.
2. Evidence Based Medicine (2002), 7 (4), 110.