Aspirin Therapy for Secondary Prevention of Ischemic Stroke

Introduction to Aspirin Therapy

The American College of Chest Physicians recommends that patients with a history of noncardioembolic ischemic stroke should continue aspirin indefinitely as long-term secondary prevention therapy at a dose of 75-100 mg once daily 1, 2, 3, 4

Initiate aspirin within 48 hours of stroke onset at a loading dose of 160-325 mg to achieve rapid platelet inhibition and reduce early recurrent stroke risk by approximately 60% 1, 2, 3, 4

After the acute phase, transition to a maintenance dose of 75-100 mg daily for indefinite secondary prevention 1, 2, 3, 4
The American College of Chest Physicians guidelines (Grade 1A recommendation) specify that this long-term antiplatelet therapy should continue lifelong in patients with a history of noncardioembolic ischemic stroke or TIA 1, 2, 3, 4

Clopidogrel (75 mg once daily) or aspirin/extended-release dipyridamole (25 mg/200 mg twice daily) are preferred over aspirin monotherapy for long-term secondary prevention (Grade 2B) 1, 2, 3, 4
Clopidogrel 75 mg daily is recommended as a safe and alternative to aspirin monotherapy for patients who cannot tolerate aspirin 1, 5

For patients with cardioembolic stroke and atrial fibrillation, switch from aspirin to oral anticoagulation (warfarin with INR 2.0-3.0 or direct oral anticoagulant) for long-term therapy, as anticoagulation is superior to aspirin in this population 1, 3, 7
Bridge with aspirin until anticoagulation reaches therapeutic levels, typically initiating anticoagulation within 1-2 weeks after stroke onset 3, 6

Do not discontinue aspirin after an arbitrary time period (e.g., 6 months or 1 year) in patients with noncardioembolic stroke, as the benefit persists indefinitely 1, 2, 3, 4
Avoid using dual antiplatelet therapy (aspirin plus clopidogrel) for long-term secondary prevention beyond 21-90 days, as bleeding risk outweighs benefit 1, 2, 3
Do not use subtherapeutic aspirin doses (<75 mg) for long-term secondary prevention, as efficacy is reduced 1, 2, 3, 4