Which initial anticoagulant is appropriate for a new deep vein thrombosis with bridging to long-term therapy?

• A. Warfarin
• B. Direct oral anticoagulant without bridging
• C. Low-molecular-weight heparin with bridging
• D. Aspirin

Answer: (C)

Starting treatment for a new deep vein thrombosis aims to provide immediate, reliable anticoagulation while a long-term plan (typically a vitamin K antagonist like warfarin) becomes therapeutic. Warfarin has a delayed onset and can cause a transient, procoagulant period early in therapy due to depletion of protein C and S. To cover that gap, you bridge with a fast-acting anticoagulant such as low-molecular-weight heparin. LMWH provides reliable anticoagulation right away and is overlapped with warfarin until the INR reaches the target range (usually 2–3) for at least 24 hours. After that, you can discontinue the heparin and continue with long-term therapy using warfarin. Aspirin does not provide adequate treatment for DVT, and while direct oral anticoagulants are often used without bridging, the scenario described specifically involves bridging to a long-term therapy, which is classically accomplished with LMWH bridging to warfarin.