Comparing subcutaneous danaparoid with intravenous unfractionated heparin for the treatment of venous thromboembolism. A randomized controlled trial

Objective: To compare the efficacy and safety of two subcutaneous doses of danaparoid with that of continuous intravenous administration of unfractionated heparin in the treatment of venous thromboembolism. Design: An open-label, randomized, multicenter clinical trial. Setting: One university hospital and two university-affiliated hospitals. Patients: 209 patients suspected to have venous thromboembolism. Of these, 188 had a confirmed diagnosis (by ventilation-perfusion lung scan and ultrasonography or contrast venography of the leg) and received study medication. Interventions: Patients were randomly assigned to either low-dose danaparoid (intravenous loading dose of 1250 U followed by 1250 U administered subcutaneously twice daily [n = 65]); high-dose danaparoid (intravenous loading dose of 2000 U followed by 2000 U administered subcutaneously twice daily [n = 63]); or unfractionated heparin (intravenous loading dose of 2500 U followed by dose-adjusted continuous infusion [n = 60]). Treatment lasted at least 5 days and was continued until anticoagulation (achieved with acenocoumarol) was adequate. Measurements: Efficacy determined clinically and by repeated imaging tests on treatment days 5 to 8; safety determined by daily assessment for bleeding. Results: Two lung scans were done in each of 179 patients; ultrasonography or venography of the leg was done twice in each of 173 patients; and both repeated leg and lung tests were done in 166 patients. A significant reduction in recurrence or extension of venous thromboembolism was seen in patients receiving high-dose danaparoid (8 of 63 [13%]) compared with patients receiving intravenous unfractionated heparin (17 of 60 [28%]; relative risk, 0.45 [95% CI, 0.21 to 0.96]). Four of 61 patients receiving high-dose danaparoid (7%) and 14 of 58 patients receiving unfractionated heparin (24%) had recurrence of pulmonary embolism (relative risk, 0.27 [CI, 0.09 to 0.78]); 3 of 58 patients receiving high-dose danaparoid (5%) and 6 of 54 patients receiving unfractionated heparin (11%) had recurrence of deep venous thrombosis (relative risk, 0.47 [CI, 0.12 to 1.77]). Occurrence of major and minor bleeding was similar in the three groups; major bleeding occurred in 1 patient receiving low-dose danaparoid, 1 patient receiving high-dose danaparoid, and 2 patients receiving heparin. Conclusions: Our results suggest that high-dose danaparoid is safer and more effective than unfractionated heparin for the treatment of venous thromboembolism.