Aspirin to Prevent Stroke in Nonrheumatic Atrial Fibrillation

To the Editor: The value of aspirin for the prevention of ischemic stroke in patients with nonrheumatic atrial fibrillation has been endorsed in two large, placebo-controlled, randomized, double-blind clinical trials. Using intention-to-treat analysis, one reported a 42 percent reduction in ischemic strokes 1 and the other a 16 percent reduction. 2 Pooled analysis showed an overall reduction of 35 percent. 3 Despite these findings some have continued to express doubts about the efficacy of aspirin. 4 When the Stroke Prevention in Atrial Fibrillation (SPAF) study was notified by the independent safety and monitoring committee that the placebo arm of our trial should be terminated, . . .