A Comparison of Three Months of Anticoagulation with Extended Anticoagulation for a First Episode of Idiopathic Venous Thromboembolism

Acute venous thromboembolism is usually treated with a five-to-seven-day course of unfractionated or low-molecular-weight heparin, followed by a three-month course of oral anticoagulant therapy. 1 Subgroup analyses of the results of a number of recent studies suggest that, after anticoagulant therapy is stopped, the risk of recurrent venous thromboembolism is greater among patients who have a persistent risk factor for thrombosis and those whose initial episode of thrombosis occurred in the absence of an apparent risk factor than it is among patients in whom thrombosis develops in association with a transient risk factor, such as surgery. 2 – 5 On the basis of . . .