The absolute risk reduction was 2.7% per year (from 4.5% per year in control subjects) in primary prevention subjects and 8.4% per year (from 12% per year in control subjects) in secondary Aspirin and APT Compared With Placebo or Control: In a meta-analysis of 8 trials of 4,876 subjects, APT compared with control or placebo was associated with a 22% (95% CI, 6-35) relative risk reduction in stroke The Stroke Prevention in AF (SPAF-I) study demonstrated decrease in risk of stroke from 6.3% per year in placebo subjects to 3.6% per year but a meta-analysis of 7 trials of 3,990 subjects found no signi cant bene t. SPAF-I was the only trial suggestive of a bene t for aspirin compared with placebo, but there was internal heterogeneity between the anticoagulation-eligible and anticoagulation-ineligible subgroups, and given the trial was stopped early, the effect size could have been exaggerated. Aspirin also showed no bene t in the elderly, or in preventing severe strokes. All these trials had signi cant heterogeneity in study design, variability in aspirin dose tested, short follow-up, and predated contemporary use of oral anticoagulation in AF. The Atrial Fibrillation Clopidogrel Trial With Irbesartan for Prevention of Vascular Events (ACTIVE-A) trial, which also predated the investigation of NOACs, compared aspirin plus clopidogrel vs aspirin monotherapy among patients in whom VKA was The study found a decrease in risk of stroke with dual antiplatelet therapy (DAPT), but the major bleeding rates with aspirin-clopidogrel were comparable to rates seen with warfarin (approximately 2% per year). 