Aspirin for Secondary Prevention of Coronary Artery Disease

Evidence for Aspirin in Secondary Prevention

The American College of Cardiology and other societies recommend long-term low-dose aspirin (75-100 mg daily) or clopidogrel (75 mg daily) as single antiplatelet therapy to reduce mortality and cardiovascular events in patients with established coronary artery disease 1, 2
Aspirin 75-100 mg daily is recommended lifelong in patients with prior myocardial infarction (MI) or remote percutaneous coronary intervention (PCI) after an initial period of dual antiplatelet therapy (DAPT) 3
Clopidogrel 75 mg daily is an equally effective alternative for patients who are intolerant or allergic to aspirin 4, 5
Single antiplatelet therapy is preferred over continued dual antiplatelet therapy after the first year post-acute coronary syndrome (ACS) 1, 2

After PCI, 81 mg of aspirin daily is reasonable in preference to higher maintenance doses 4
For patients undergoing coronary artery bypass grafting (CABG), aspirin should be started within 6 hours after surgery to reduce saphenous vein graft closure, with dosing regimens of 100-325 mg daily for 1 year 4, 5

For patients with ACS who undergo PCI with stent placement, dual antiplatelet therapy with aspirin plus a P2Y12 inhibitor (ticagrelor, clopidogrel, or prasugrel) is recommended for up to 12 months 1, 2, 4
After this initial period, single antiplatelet therapy with aspirin or clopidogrel is recommended over continued dual antiplatelet therapy 1, 2

Proton pump inhibitors may be effective in reducing the risk of gastrointestinal bleeding in patients on antithrombotic therapy, particularly those at increased risk 3
Patients at increased risk of bleeding include the elderly, those with a history of GI bleeding or peptic disease, high alcohol consumption, chronic use of steroids or NSAIDs, or receiving a combination of antithrombotic drugs 3

Continuing dual antiplatelet therapy beyond 12 months after ACS or stent placement without specific indications increases bleeding risk without additional benefit 6
Using full-intensity oral anticoagulation in CAD patients without another indication (such as atrial fibrillation) should be avoided as it increases bleeding risk without additional benefit 4, 5
Failure to consider drug interactions: some NSAIDs can block aspirin's access to the active site of COX-1, potentially reducing its effectiveness 7