Lancet
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Randomized Controlled Trial Comparative Study Clinical Trial
Warfarin versus aspirin for prevention of thromboembolism in atrial fibrillation: Stroke Prevention in Atrial Fibrillation II Study.
Warfarin is an established treatment for prevention of ischaemic stroke in patients with atrial fibrillation, but the value of this agent relative to aspirin in unclear. In the first Stroke Prevention in Atrial Fibrillation (SPAF-I) study, direct comparison of warfarin with aspirin was limited by the small number of thromboembolic events. SPAF-II aims to address this issue and also to assess the differential effects of the two treatments according to age. ⋯ Younger patients without risk factors had a low rate of stroke when treated with aspirin. In older patients the rate of stroke (ischaemic and haemorrhagic) was substantial, irrespective of which agent was given. Patient age and the inherent risk of thromboembolism should be considered in the choice of antithrombotic prophylaxis for patients with atrial fibrillation.