Dual Antiplatelet Therapy After 2 Weeks in Large Vessel Stroke

Introduction to Dual Antiplatelet Therapy

The American Heart Association recommends that dual antiplatelet therapy (DAPT) should not be initiated after 2 weeks in patients with large vessel stroke, regardless of decreased hemorrhagic transformation risk 1, 2, 3.

DAPT must be initiated within 24-72 hours of symptom onset to provide benefit in stroke prevention, as recommended by the American College of Cardiology 1, 2.
The therapeutic window closes rapidly because the benefit of DAPT is concentrated in preventing early recurrent stroke within the first 21 days after the index event, according to the American Heart Association 1, 2, 4.
Starting DAPT after 2 weeks provides no additional benefit over single antiplatelet therapy (SAPT) for long-term secondary prevention, as stated by the American Stroke Association 1, 3.

DAPT is contraindicated in moderate to severe stroke (NIHSS >3) at any time point, including the acute phase, as recommended by the American College of Cardiology 1, 2, 3, 4.
Large vessel strokes typically present with NIHSS scores >3, making them ineligible for DAPT based on stroke severity criteria alone, according to the American Heart Association 1, 3.

DAPT beyond 90 days is associated with increased major hemorrhage risk (HR 2.32, 95% CI 1.10-4.87) without additional stroke prevention benefit, as reported by the American College of Cardiology 1, 3.
For every 1000 patients treated with DAPT for 90 days, 15 ischemic strokes would be prevented but 5 major hemorrhages would result, according to the American Heart Association 1, 2.

All patients with large vessel stroke should receive SAPT (aspirin 81-325 mg daily or clopidogrel 75 mg daily) indefinitely for long-term secondary prevention, as recommended by the American College of Cardiology 1, 2, 3.
SAPT should be continued long-term regardless of when it was initiated after the acute stroke period, according to the American Stroke Association 1, 3.

If the large vessel stroke is cardioembolic (e.g., atrial fibrillation), anticoagulation should be initiated within 2 weeks based on stroke severity: mild stroke >3 days, moderate stroke >6-8 days, severe stroke >12-14 days, as recommended by the American College of Chest Physicians and the European Society of Cardiology 5, 6.
Anticoagulation timing is guided by stroke size and hemorrhagic transformation risk, not by the 2-week timepoint specifically, according to the American College of Chest Physicians and the European Society of Cardiology 5, 6.