A risk-stratified approach to venous thromboembolism prophylaxis with aspirin or warfarin following total hip and knee arthroplasty: A cohort study

Introduction: Venous thromboembolism (VTE) and bleeding events following total knee and hip arthroplasty (TKA/THA) are associated with significant morbidity. Clinical guidelines recommend administration of pharmacologic VTE prophylaxis post-operatively, although controversy exists regarding optimal prophylactic strategies. Methods: We performed a retrospective cohort study in patients who underwent elective TKA/TKA in an academic medical center. Patients were stratified by surgery type (TKA/THA) and VTE risk determined by a novel risk stratification protocol and compared pre- and post-protocol implementation. Patients received warfarin preprotocol and either aspirin or warfarin post-protocol for VTE prophylaxis. Natural language processing identified VTE events and ICD codes were used to identify bleeding events, with all events validated manually. Results: A total of 1379 surgeries were included for analysis, 839 TKAs and 540 THAs. Post-protocol implementation, 445 (94.1%) patients following TKA and 294 (97.4%) patients following THA received aspirin for VTE prophylaxis. A significant reduction in bleeding events (hazard ratio [HR] = 0.19, p = 0.048) was observed in low-risk THA patients treated with aspirin (post-protocol) compared patients treated with warfarin (preprotocol). Bleeding events did not differ significantly between low-risk TKA patients treated with aspirin or warfarin. No significant differences in VTE events were observed following the protocol implementation. Conclusions: The use of a novel risk stratification system to guide VTE prophylaxis selection between aspirin or warfarin following TKA and THA appears safe and effective. Among low-risk patients, aspirin use was associated with fewer bleeding events following THA, without an observed increase in VTE events.

Automated summary

The study investigated the efficacy of aspirin and warfarin for VTE prophylaxis following total knee and hip arthroplasty. The results showed that in low-risk patients undergoing total hip arthroplasty, the use of aspirin significantly reduced bleeding events. There was no significant difference in bleeding events between aspirin and warfarin in low-risk patients undergoing total knee arthroplasty.