Single-arm study of bridging therapy with low-molecular-weight heparin for patients at risk of arterial embolism who require temporary interruption of warfarin

• Published in: Circulation (New York, N.Y.) N.Y.), 2004-09, Vol.110 (12), p.1658-1663
• Main Authors: KOVACS, M. J, KEARON, C, WELLS, P. S, RODGER, M, ANDERSON, D. R, TURPIE, A. G. G, BATES, S. M, DESJARDINS, L, DOUKETIS, J, KAHN, S. R, SOLYMOSS, S
• Format: Article
• Language: English
• Subjects: Anticoagulants - administration & dosage; Anticoagulants - adverse effects; Anticoagulants - therapeutic use; Arterial Occlusive Diseases - epidemiology; Arterial Occlusive Diseases - prevention & control; Aspirin - administration & dosage; Atrial Fibrillation - surgery; Biological and medical sciences; Blood and lymphatic vessels; Blood Loss, Surgical; Blood. Blood coagulation. Reticuloendothelial system; Cardiology. Vascular system; Cardiovascular system; Cohort Studies; Dalteparin - administration & dosage; Dalteparin - adverse effects; Dalteparin - therapeutic use; Diseases of the peripheral vessels. Diseases of the vena cava. Miscellaneous; Elective Surgical Procedures; Feasibility Studies; Heart Valve Prosthesis Implantation; Humans; International Normalized Ratio; Intraoperative Complications - epidemiology; Intraoperative Complications - prevention & control; Medical sciences; Pharmacology. Drug treatments; Postoperative Complications - epidemiology; Postoperative Complications - prevention & control; Postoperative Hemorrhage - chemically induced; Premedication; Preoperative Care; Prospective Studies; Risk; Thromboembolism - epidemiology; Thromboembolism - prevention & control; Treatment Outcome; Vasodilator agents. Cerebral vasodilators; Vitamin K - administration & dosage; Warfarin - administration & dosage
• ISSN: 0009-7322; 1524-4539
• DOI: 10.1161/01.CIR.0000142859.77578.C9

When warfarin is interrupted for surgery, low-molecular-weight heparin is often used as bridging therapy. However, this practice has never been evaluated in a large prospective study. This study was designed to assess the efficacy and safety of bridging therapy with low-molecular-weight heparin initiated out of hospital. This was a prospective, multicenter, single-arm cohort study of patients at high risk of arterial embolism (prosthetic valves and atrial fibrillation with a major risk factor). Warfarin was held for 5 days preoperatively. Low-molecular-weight heparin was given 3 days preoperatively and at least 4 days postoperatively. Patients were followed up for 3 months for thromboembolism and bleeding. Eleven Canadian tertiary care academic centers participated; 224 patients were enrolled. Eight patients (3.6%; 95% CI, 1.8 to 6.9) had an episode of thromboembolism, of which 2 (0.9%; 95% CI, 0.2 to 3.2) were judged to be due to cardioembolism. Of these 8 episodes of thromboembolism, 6 occurred in patients who had warfarin deferred or withdrawn because of bleeding. There were 15 episodes of major bleeding (6.7%; 95% CI, 4.1 to 10.8): 8 occurred intraoperatively or early postoperatively before low-molecular-weight heparin was restarted, 5 occurred in the first postoperative week after low-molecular-weight heparin was restarted, and 2 occurred well after low-molecular-weight heparin was stopped. There were no deaths. Bridging therapy with subcutaneous low-molecular-weight heparin is feasible; however, the optimal approach for the management of patients who require temporary interruption of warfarin to have invasive procedures is uncertain.