A Phase IV Study of Thromboembolic and Bleeding Events Following Hip and Knee Arthroplasty Using Oral Factor Xa Inhibitor

BackgroundMultiple randomized controlled trials have documented the effectiveness of rivaroxaban in the prevention of venous thromboembolism up to 1-month following total joint arthroplasty. However, the effectiveness and safety of rivaroxaban in the real-world setting, outside of the strict protocols used by randomized clinical trials, are unknown.MethodsThis was a prospective, observational, noninterventional, phase IV study of 3914 consecutive patients who underwent total joint arthroplasty from June 2010 to December 2012. Patients were treated with rivaroxaban 10 mg by mouth daily starting postoperative day 1 and continued for 15 days. Participants were followed up in clinic at 6 weeks and contacted by telephone at 12 weeks. The primary outcome of interest was symptomatic venous thromboembolism; secondary outcomes included bleeding events, transfusion requirements, and death.ResultsThe incidence of symptomatic deep venous thrombosis at 3 months was 0.5% (n = 18). Only 1 deep venous thrombosis event occurred within 7 days of surgery. The incidence of symptomatic pulmonary embolism (PE) at 3 months was 0.7% (n = 28). Thirteen PEs (46%) occurred within 7 days of surgery. The rate of major bleeding while on prophylaxis was 0.1%. Only 5% of patients received a blood transfusion. No deaths were attributed to thromboembolic events.ConclusionThis prospective, observational, phase IV study demonstrates that rivaroxaban appears to protect patients against symptomatic PE and is not associated with major bleeding events when used in a real-world setting as described.