Pulmonary Embolism Rates Following Total Hip Arthroplasty With Prophylactic Anticoagulation: Some Pulmonary Emboli Cannot Be Avoided

Background: A symptomatic pulmonary embolism (PE) after total joint arthroplasty has been described as a "never event." Despite potent anticoagulants and improvements in patient care, PE continues to occur following total hip arthroplasty (THA). This study evaluates symptomatic PE rates over time in THA patients enrolled in multicenter randomized clinical trials (RCTs) assessing the efficacy of venous thromboembolism prophylaxis regimens. Methods: The MEDLINE and Cochrane Central Register of Controlled Trials were searched to identify clinical trials assessing prophylactic anticoagulation in patients undergoing THA between January 1995 and December 2015. Inclusion criteria consisted of RCTs evaluating prophylactic anticoagulation in patients undergoing THA. A random effect model was used to combine PE rates across studies. Results: A total of 21 studies (34,764 patients) were included. Patients were administered low molecular weight heparin (13,590 patients), oral factor Xa inhibitors (6609 patients), oral direct thrombin inhibitors (5965 patients), indirect factors Xa/IIa inhibitors (3444 patients), aspirin (2427 patients), and warfarin (489 patients). Mobile compression was used in 199 patients, and placebo was used in 2041 patients. Across all included studies, the estimated PE rate was 0.21% (95% confidence interval: 0.13%, 0.32%). Between 1997 and 2013, the proportion of PEs did not change in regression analysis. Conclusion: Although the PE rate was low, it was consistent throughout the 17 years spanning these RCTs, which excluded patients with significant morbidity. These results suggest that even healthy THA patients receiving aggressive anticoagulation still have a risk for PE, and the "never event" designation requires reassessment. (C) 2016 Elsevier Inc. All rights reserved.