Comparison of efficacy and safety between aspirin and oral anticoagulants for venous thromboembolism prophylaxis after major orthopaedic surgery: a meta-analysis of randomized clinical trials

Background: venous thromboembolism (VTE) is one of the most common complications after major orthopaedic surgery. Recent studies have suggested that aspirin may also be effective in preventing VTE, but it is still controversial whether it can be routinely used. Objectives: To compare the efficacy and safety of aspirin against oral anticoagulants in the prevention of VTE following total hip arthroplasty (THA), total knee arthroplasty (TKA) or hip fracture surgery (HFS). Methods: Relevant publications have been obtained using electronic search databases such as PubMed, Embase, Web of Science, Cochrane Library, and Clinical Trials. gov. from inception to 20 July 2023. Only RCTs evaluating the efficacy and safety of aspirin compared with oral anticoagulants undergoing major orthopaedic surgery were included in the meta-analysis. The primary outcome reported was any VTE event (including deep vein thrombosis (DVT) and pulmonary embolism (PE)). Secondary outcomes included mortality, major bleeding (including gastrointestinal bleed, cerebrovascular hemorrhage, or any bleeding requiring a return to the theater), minor bleeding (ecchymosis, epistaxis, hematuria), and wound complications. The risk of bias for all included studies was assessed according to the Cochrane Collaboration's tool. Results: After screening 974 studies, 12 randomized clinical trials (RCTs) were included, involving 5,088 participants, including 2,540 participants in aspirin, 2,205 participants in rivaroxaban, and 323 participants in warfarin. Aspirin was found to be less effective than oral anticoagulants in thromboprophylaxis after major orthopedic surgery (RR = 1.206, 95% CI 1.053-1.383). After subgroup analysis according to the type of oral anticoagulant, the results showed that aspirin was similar to rivaroxaban and inferior to warfarin. Considering that the studies in the warfarin group were all conducted before 2000, our results need to be further confirmed. In addition, the aspirin group had a higher risk of VTE than the control group in other subgroups, including a follow-up time of ≤3 months, type of procedure as TKA, high-dose aspirin (≥650 mg qd), and no combined use of mechanical prophylaxis. In terms of safety events, aspirin did not show significant differences in major bleeding (RR = 0.952, 95% CI 0.499-1.815), all-cause mortality (RR = 1.208, 95% CI 0.459-3.177), and wound-related events (RR = 0.618, 95% CI 0.333-1.145) compared with oral anticoagulants, and aspirin was associated with a reduction in the risk of minor bleeding (RR = 0.685, 95% CI 0.552-0.850) events and total bleeding (RR = 0.726, 95% CI 0.590-0.892). Conclusion: Aspirin reduces bleeding risk after major orthopedic surgery compared with oral anticoagulants, but may sacrifice VTE prevention to some extent. Updated evidence is needed to analyze the thromboprophylaxis effects of aspirin in patients undergoing major orthopedic surgery. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=463481, identifier CRD42023463481.

Rivaroxaban compared with standard thromboprophylaxis after major orthopaedic surgery: co-medication interactions

Aim

The aim of the present study was to analyse concomitant drug use and its association with outcome in patients (N = 17 701) receiving rivaroxaban or standard of care (SOC) for the prevention of venous thromboembolism after major orthopaedic surgery in the non‐interventional, phase IV XAMOS (Xarelto® in the prophylaxis of post‐surgical venous thromboembolism after elective major orthopaedic surgery of hip or knee) study.

Methods

Concomitant drug use was at the discretion of the treating physician. Prespecified co‐medications of interest were cytochrome P450 (CYP) 3A4/P‐glycoprotein inhibitors/inducers, platelet aggregation inhibitors (PAIs) and nonsteroidal anti‐inflammatory drugs (NSAIDs). Crude event incidences were compared between rivaroxaban and SOC groups.

Results

CYP3A4/P‐glycoprotein inhibitor/inducer use was infrequent, in contrast to PAI (~7%) and NSAID (~52%) use. Rivaroxaban was associated with a lower incidence of overall symptomatic thromboembolic events compared with SOC, regardless of co‐medication use. In both treatment groups, PAI users, with higher age and prevalence of cardiovascular co‐morbidities, had similar higher (>7‐fold) incidences of symptomatic arterial but not venous thromboembolic events compared with non‐users. NSAID use had no influence on thromboembolic events. However, odds ratios (ORs) for major bleeding events (European Medicines Agency definition) were higher in NSAID users compared with non‐users in rivaroxaban [OR = 1.50; 95% confidence interval (CI) 1.06, 2.13] and SOC (OR = 1.70; CI 1.16, 2.49) groups. In PAI users, ORs for major bleeding events were no different from those of non‐users in both the rivaroxaban (OR = 1.49; CI 0.84, 2.65) and SOC (OR = 1.46; CI 0.82, 2.62) groups.

Conclusions

Use of NSAIDs in XAMOS was frequent and associated with a higher frequency of bleeding events in patients receiving rivaroxaban or SOC, although the benefit–risk profile of rivaroxaban compared with SOC was maintained.

Venous thromboembolism rates in patients undergoing major hip and knee joint surgery at Waitemata District Health Board: a retrospective audit

BACKGROUND/AIM

Symptomatic venous thromboembolism (VTE) complicates approximately 4% of major orthopaedic surgical procedures performed without thromboprophylaxis. Randomised clinical trials demonstrate primary thromboprophylaxis reduces VTE rates to <1%, with low rates of clinically important bleeding, using low molecular weight heparin (LMWH), oral FXa inhibitors or thrombin inhibitors. We reviewed the rates of VTE in patients undergoing major hip/knee joint surgery at Waitemata District Health Board (WDHB).

METHODS

Cases of VTE within 90 days of orthopaedic surgery were identified by retrospective audit of data from the haematology VTE database. The number of major hip/knee joint surgeries at WDHB from January 2006 to December 2010 was obtained from clinical coding data.

RESULTS

The cumulative incidence of VTE within 90 days of surgery was 3.29%. The median time from surgery to diagnosis was 7 days. Deep vein thrombosis comprised 75% of cases, 77.6% distal and 23.2% proximal. Pulmonary embolism comprised 26.5% of VTE; 47.7% had right heart strain on computed tomography/echocardiography. Hip fracture surgery comprised one-third of patients. Of patients developing VTE, 85.5% had chemical thromboprophylaxis - aspirin 73%, LMWH 20 mg 16%, LMWH 40 mg 16%, therapeutic LMWH 3%, unfractionated heparin twice daily 1%, and warfarin 4%; 75.6% received mechanical prophylaxis, while 4% of patients received no prophylaxis.

CONCLUSION

VTE incidence after major hip/knee joint surgery at WDHB is high, with pulmonary embolism comprising almost one-third of all VTE in this study, indicating the prophylaxis given is suboptimal. Implementation of appropriate, extended duration prophylaxis as per evidence-based guidelines is required to reduce these rates.