Duration of therapy for acute venous thromboembolism

The duration of oral anticoagulant therapy for venous thromboembolism (VTE) should be individualized based on the risk for recurrent VTE if treatment is stopped and the risk for bleeding if treatment is continued. The risk of recurrence is low if thrombosis was provoked by a major reversible risk factor; 3 months of treatment is usually adequate for such patients. The risk of recurrence is high if thrombosis was unprovoked (idiopathic) or associated with a nonreversible risk factor; 6 months, and sometimes indefinite, anticoagulant therapy is indicated for such patients. The presence of nonreversible risk factors for recurrent VTE favors more prolonged therapy, whereas isolated distal deep vein thrombosis, a high risk of bleeding, and patient preference favor a shorter course of treatment.