Aspirin After Acute Ischemic Stroke

Details for This Review

Study Population: Adults presenting with acute stroke

Efficacy End Points: Death or dependence, recurrent stroke, complete recovery from stroke

Harm End Points: Symptomatic intracranial hemorrhage, major extracranial hemorrhage

Narrative: Each year in the United States, approximately 610,000 people have a stroke for the first time, and an additional 185,000 have recurrent strokes. Of these, 87% are ischemic strokes,1 and are most often caused by thrombosis or embolism and a subsequent lack of blood flow. In ischemic strokes, platelets become activated and release neurotoxic and thrombogenic molecules,2 which makes antiplatelet therapy a logical choice. A potential harm of this therapy is bleeding, especially intracranially. The goal of this summary is to provide updated evidence on the safety and effectiveness of immediate oral antiplatelet therapy in patients presenting with acute ischemic stroke.

This Cochrane systematic review identified eight randomized controlled trials involving 41,483 predominantly older patients with presumed acute ischemic stroke.3 Two studies (International Stroke Trial [IST]4 and the Chinese Acute Stroke Trial [CAST]5), accounted for 98% of the data. The IST randomized patients to receive 300 mg per day of aspirin for two weeks or no treatment, and the CAST randomized patients to receive 160 mg per day of aspirin for four weeks or placebo within 48 hours of presentation. The primary outcome was death or dependency at least one month after stroke (six months for patients in the IST and one month for patients in the CAST). Secondary outcomes measured during the treatment period (two weeks