[Prevention of embolisms in atrial fibrillation: anticoagulation and antiplatelet therapy].

Over the past five years, the results of six prospective randomized trials have set new standards in the primary and secondary prevention of thromboembolism in "nonvalvular" ("nonrheumatic") atrial fibrillation. On the one hand, they have confirmed the increased risk of stroke in these patients amounting to about 5% per year and an annual recurrence rate after a recent transient ischaemic attack or minor stroke of 12%. On the other hand, the results of these trials have unanimously demonstrated a > or = 60% risk reduction with oral anticoagulation at an acceptable risk of major bleeding complications. A reduced intensity of anticoagulant therapy with a target INR of 2.0-3.0 is effective in most of these patients. Both clinical and echocardiographic features allow the identification of subgroups at low or high risk of thromboembolic complications and provide the basis for the individual benefit-to-risk assessment of anticoagulant therapy. Aspirin is currently recommended as a second choice therapy for patients who are poor candidates for oral anticoagulants or who are considered to be at low risk for thromboembolism.