Extended venous thromboembolism prophylaxis after total hip replacement -: A comparison of low-molecular weight heparin with oral anticoagulant

Background: Oral anticoagulants and low-molecular-weight heparin are both recommended for venous thromboembolism prophylaxis after total hip replacement. To date; these regimens have not been compared by means of clinical end points in the extended prophylaxis setting. Methods: We randomly assigned 1279 patients 3 days after total hip replacement surgery to fixed-dose subcutaneous low-molecular-weight heparin (reviparin sodium, 4200 anti-Xa IU) or adjusted-dose oral anticoagulant (international normalized ratio, 2-3; acenocoumarol) for a 6-week period. The primary end point was the failure rate, defined as the combined clinical events of a confirmed symptomatic thromboembolic event, a major hemorrhage, or death. All patients were followed up throughout the study interval. The primary objective was to compare the observed cumulative failure rate in the low-molecular-weight heparin vs oral anticoagulant group. Results: In the intent-to-treat population, objectively documented symptomatic thromboembolic events occurred in 15 (2.3%) of 643 patients vs 21 (3.3%) of 636 patients receiving low-molecular-weight heparin or oral anticoagulants, respectively (P = .30; 95% confidence interval for the difference, -0.8% to 2.8%). Major bleeding occurred in 9 (1.4%) of 643 patients vs 35 (5.5%) of 636 patients receiving low-molecular-weight heparin or oral anticoagulants, respectively (P = .001). The failure rate was 24 (3.7%) of 643 patients compared with 53 (8.3%) of 636 patients who received low-molecular-weight heparin or oral anticoagulants (P = .001). Conclusions: A significantly higher benefit-risk ratio was observed for patients undergoing elective hip replacement who received extended out-of-hospital prophylaxis with low-molecular-weight heparin vs acenocoumarol. Low-molecular-weight heparin prophylaxis was at least as effective as oral anticoagulants, but with a marked improvement in safety.