Duration of anticoagulant therapy for patients with venous thromboembolism

摘要

A 77-year-old woman presents to the emergencydepartment with extensive right leg DVT. Thepatient is treated for eight days with dalteparinand warfarin; LMWH therapy is discontinued becausethe INR is stable and within the therapeuticrange (2.0–3.0). How long should warfarin therapybe continued?Abstract: In principle, the answer to this questionis obvious: “as long as the risk of continued therapyis outweighed by the benefit.” In practice, determiningan individual patient's risk of recurrentvenous thromboembolism (VTE) without warfarinor other vitamin K antagonists is difficult. However,there are many factors (both intrinsic and environmental)that can alter the risk of VTE recurrence.This paper will discuss evidence and considerations(including the issue of bleeding risk) that may berelevant to decisions about duration of anticoagulanttherapy for patients with VTE.