SOURCE: Anderson DR, et al. N Engl J Med 2018;378:699-707.
The combined benefits of improved efficacy and convenience of direct oral anticoagulants (i.e., apixaban, dabigatran, edoxaban, rivaroxaban) in the setting of atrial fibrillation makes them a preferred choice. For chronic anticoagulation subsequent to recurrent deep vein thrombosis or pulmonary embolism, direct oral anticoagulants are similarly attractive when compared to warfarin. Might direct oral coagulants offer some advantage for extended venous thromboembolism (VTE) thromboprophylaxis in patients undergoing knee or hip arthroplasty who are known to suffer an increased risk of VTE in the immediate postoperative period?
Anderson et al performed a double-blind, randomized, controlled trial of knee and hip arthroplasty patients. After a run-in period of rivaroxaban 10 mg daily through postoperative day five, subjects were randomized to either continue rivaroxaban or switch from rivaroxaban to aspirin (81 mg/d). This additional VTE thromboprophylaxis continued for nine days post-knee arthroplasty (hence, 14 days total thromboprophylaxis) and 30 days post-hip arthroplasty (hence, 35 days total thromboprophylaxis).
VTE events were rare in both groups (< 1%), and there was no statistically significant difference in VTE events between aspirin and rivaroxaban, nor was there any significant difference in rates of bleeding. For now, aspirin should remain the postoperative choice for extended prophylaxis after knee and hip arthroplasty.