Background: Most patients undergoing total hip replacement (THR) and total knee replacement (TKR) require anticoagulant therapy to reduce venous thromboembolism (VTE) risk. Compared with injectable low-molecular-weight heparin (LMWH), warfarin, and newer oral agents, aspirin is easily administered, inexpensive, and well tolerated and requires no monitoring. There are observational data to support aspirin as VTE prophylaxis after THR and TKR. However, high-quality randomized, clinical trials (RCT) in favor of aspirin have been limited. Recently, a large RCT (n = 3,224) that compared aspirin to rivaroxaban after THR and TKR has been published that supports aspirin use for VTE prophylaxis.
Study design: Systematic review and meta-analysis.
Setting: Seven studies from North America, four from Asia, and two from Europe.
Synopsis: In a meta-analysis comprising 13 RCT including 6,060 participants (2,969 aspirin and 3,091 comparator), there was no statistically significant difference in the risk of venous thromboembolism (including deep-vein thrombosis and pulmonary embolism) when comparing aspirin with other anticoagulants (LMWH, rivaroxaban) in patients undergoing THR and TKR. Also, there were no differences in the risk of adverse events, such as bleeding, wound complications, MI, and death, when aspirin was compared with other anticoagulants.
This systematic review and meta-analysis included trials from around the world, including the most recent and largest in this area. However, because of the heterogeneity and high risk of bias encountered in most RCTs included in this analysis, additional large, well-designed RCTs are needed to validate findings of this review.
Bottom line: Findings of the current meta-analysis support the use of aspirin for VTE prophylaxis after THR and TKR, in line with the 2012 recommendations of the American College of Chest Physicians.
Citation: Matharu GS et al. Clinical effectiveness and safety of aspirin for venous thromboembolism prophylaxis after total hip and knee replacement. JAMA Intern Med. 2020 Feb 3;180(3):376-84.
Dr. Mehta is assistant professor of medicine, section of hospital medicine, at the University of Virginia School of Medicine, Charlottesville.