Warfarin Sodium versus Low-Dose Heparin in the Long-Term Treatment of Venous Thrombosis

TLDR

Acute deep‑vein thrombosis is usually treated with intravenous heparin followed by oral anticoagulants for weeks to months. We compared adjusted‑dose warfarin sodium with fixed low‑dose subcutaneous heparin for preventing recurrent deep‑vein thrombosis. Sixty‑eight patients with venographically confirmed acute deep‑vein thrombosis received initial intravenous heparin and were then randomized to secondary prophylaxis with either treatment. Adjusted‑dose warfarin sodium prevented recurrent venous thromboembolism (0/33) versus 9/35 with subcutaneous heparin (P = 0.001) but caused significant bleeding (7/33, 4 major) versus none with heparin (P < 0.005).

Abstract

Acute deep-vein thrombosis is usually treated with intravenous heparin for a number of days, then with oral anticoagulants for weeks to months. We have compared adjusted-dose warfarin sodium with fixed low-dose subcutaneous heparin in the prevention of recurrent deep-vein thrombosis. Sixty-eight patients with acute deep-vein thrombosis confirmed by venography were treated with intravenous heparin and then randomized to secondary prophylaxis. Nine of 35 patients receiving subcutaneous heparin, but none of 33 receiving warfarin sodium, had new episodes of objectively documented venous thromboembolism (P = 0.001). Seven patients on warfarin sodium experienced bleeding complications (of which four were major), as compared with no patients receiving subcutaneous heparin (P less than 0.005). Thus, adjusted-dose warfarin sodium is more effective than low-dose subcutaneous heparin in preventing recurrent venous thromboembolism, but its use is accompanied by a significant risk of bleeding.