l The CI does not exclude the possibility of appreciable harm or bene t with antiplatelet therapy. m Based on rate of systemic embolism on aspirin of per patient-y reported in the IPD meta-analysis of warfarin vs aspirin by van Walraven et al and a relative risk of for aspirin vs no therapy for systemic embolism. e544S Antithrombotic Therapy for Atrial Fibrillation Table [Sections Should VKAs Rather Than Aspirin Be Used in Patients With AF? a Quality Assessment Summary of Findings No. 