Warfarin (target INR 2.0-3.0) reduces the risk of stroke by 68% (95% CI 50-79%) in patients with atrial fibrillation, while aspirin provides a 21% risk reduction.
Does antithrombotic therapy reduce the risk of stroke and thromboembolic events in patients with atrial fibrillation?
Risk stratification should be used to identify high-risk atrial fibrillation patients who would benefit from anticoagulation with warfarin over aspirin.
Effect estimate: Risk reduction 68% (95% CI 50-79)
Atrial fibrillation is the commonest sustained disorder of cardiac rhythm and is associated with increased risk of stroke and thromboembolic events. Warfarin (dose-adjusted to a target INR of 2.0-3.0) has been well established to reduce this risk of stroke by 68% (95% CI 50-79%), while aspirin provides a risk reduction of 21% (95% CI 0-38%). Nevertheless, warfarin confers a risk of bleeding and the inconvenience of regular monitoring checks, while aspirin seems effective only for certain low-risk subgroups. Thus there have been strenuous efforts to improve thromboprophylaxis in atrial fibrillation, by using low-intensity anticoagulation regimens, combination antiplatelet therapy and refinement of risk stratification strategies. Attempts at using a low-intensity, fixed-dose warfarin regimen have, however, been disappointing. For now, a strategy of risk stratification should be adopted to identify highest risk patients with atrial fibrillation who would benefit from anticoagulation.
Li-Saw-Hee et al. (Mon,) conducted a review in Atrial fibrillation. Warfarin was evaluated on Stroke (Risk reduction 68%, 95% CI 50-79). Warfarin (target INR 2.0-3.0) reduces the risk of stroke by 68% (95% CI 50-79%) in patients with atrial fibrillation, while aspirin provides a 21% risk reduction.
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