A systematic review on the effect of aspirin in the prevention of post-operative arterial thrombosis in patients undergoing total hip and total knee arthroplasty

Introduction: Major surgery is associated with increased risk of venous thromboembolism (VTE), which is decreased by anticoagulant drugs. Evidence is growing that major surgery is associated with increased risk of arterial thrombosis (AT). With the aim of testing aspirin ability in reducing the risk of post-operative AT, we performed a systematic review of studies in which acetylsalicylic acid (ASA) was compared to anticoagulant drugs in VTE prophylaxis of patients undergoing total hip replacement (THR) or total knee replacement (TKR). Materials and Methods: Studies were identified by reviewing the reference of the ACCP guidelines and by electronic search of MEDLINE database from January 2012 to December 2013 and of the web database www.trialresultscenter.org. Results: We analyzed 5 of the 78 studies that were identified by our search strategy; they included 5179 patients; the median follow-up was 90. days. The incidence of post-operative AT tended to be lower in ASA-treated patients, compared to anticoagulant-treated patients, although the difference did not reach statistical significance (OR 0.56, 95%CI 0.23-1.35). In contrast, the incidence of post-operative VTE tended to be higher in ASA-treated patients, compared to anticoagulant-treated patients (1.48, 95% CI 0.93-2.36). Conclusions: Due to the heterogeneity and low quality of the studies, which do not allow firm conclusions, it is uncertain whether aspirin is effective in reducing the incidence of postoperative AT. Our results do emphasize the need for developing specifically designed studies to test the safety and efficacy of ASA in the prevention of post-operative AT.