Prevention of arterial thromboembolism in patients with atrial fibrillation

Background: Patients with atrial fibrillation have a 5% risk per year for ischemic stroke. The aim of antithrombotic therapy is to prevent arterial thromboembolic events. As anticoagulation increases the frequency of bleeding, the risk and benefits of this therapy have to be assessed for each patient. Patients at Risk: The patients can be classified as low risk (< 2% stroke/year), medium risk (2-6% stroke/year), and high-risk patients (> 6% stroke/year). Parameters for the risk stratification are the patient age and cardiac as well as non-cardiac diseases. Prevention: Patients with a low risk need no anticoagulation or can take aspirin. Patients with a high risk should receive oral anticoagulation with an INR range from 2.0 to 3.0. Newer guidelines recommend also for patients with intermediate level of stroke risk instead of aspirin the prescription of oral anticoagulation. Patients with a medium risk can interrupt the oral anticoagulation before surgery or invasive diagnostic procedures for 1 week, patients with a high risk should receive heparin. 3-4 weeks before and after cardioversion the standard therapy is oral anticoagulation.