Current Trends in the Duration of Anticoagulant Therapy for Venous Thromboembolism: A Systematic Review

Anticoagulation therapy is the first line and drug of choice for both the treatment and prophylaxis of venous thromboembolism (deep vein thrombosis and/or pulmonary embolism). Anticoagulation drugs, ranging from different preparations of heparin, warfarin, and newer direct oral drugs such as rivaroxaban and dabigatran, work mainly by inhibiting important factors and enzymes in the coagulation cascade by preventing fibrin formation, platelet aggregation, and clot assembly. With recurrent thrombosis and embolisms being a feared complication for many physicians treating such cases, anticoagulation is often extended beyond the initial three- to six-month acute phase after an incident of venous thromboembolism. For some groups of patients, anticoagulation needs to be offered indefinitely to decrease the risk of a recurrent thrombosis. However, this concomitantly increases obvious and dangerous adverse effects such as increased risk of hemorrhage, as the ability to clot is hindered. This tradeoff between recurrent venous thromboembolism and bleeding is what underscores the controversy of the clinical question: for how long should anticoagulation be administered for venous thromboembolism? This review analyzes the use of anticoagulants in different types of venous thromboembolism and remarks on current consensus and trends on the length of anticoagulation treatment. We are doing so while acknowledging that venous thromboembolism management is an active area of research that is rapidly evolving. A literature search was performed looking at recent studies on anticoagulant administration for the treatment of venous thromboembolism with a focus on varying durations and patient populations. Factors that affect clinical decisions of duration are also elucidated. The most clinically relevant anticoagulants were discussed and their effects on the risk of recurrent thrombosis and embolism, and the risk of bleeding in relation to other drugs were analyzed. Ultimately, this article discussed patterns of anticoagulant treatments duration and which patient groups are likely to benefit the most from certain durations, shedding light on the ambiguity in how physicians should approach administering anticoagulation therapy over time for a broad range of presentations of venous thromboembolism.