Effect of Aspirin vs Enoxaparin on 90-Day Mortality in Patients Undergoing Hip or Knee Arthroplasty

Abstract

ImportanceIschemic heart disease remains the leading cause of mortality following hip and knee arthroplasty. Due to its antiplatelet and cardioprotective properties, aspirin has been proposed as an agent that could reduce mortality when used as venous thromboembolism (VTE) prophylaxis following these procedures.ObjectiveTo compare aspirin with enoxaparin in reducing 90-day mortality for patients undergoing hip or knee arthroplasty procedures.Design, Setting, and ParticipantsThis study was a planned secondary analysis of the CRISTAL cluster randomized, crossover, registry-nested trial performed across 31 participating hospitals in Australia between April 20, 2019, and December 18, 2020. The aim of the CRISTAL trial was to determine whether aspirin was noninferior to enoxaparin in preventing symptomatic VTE following hip or knee arthroplasty. The primary study restricted the analysis to patients undergoing total hip or knee arthroplasty for a diagnosis of osteoarthritis only. This study includes all adult patients (aged ≥18 years) undergoing any hip or knee arthroplasty procedure at participating sites during the course of the trial. Data were analyzed from June 1 to September 6, 2021.InterventionsHospitals were randomized to administer all patients oral aspirin (100 mg daily) or subcutaneous enoxaparin (40 mg daily) for 35 days after hip arthroplasty and 14 days after knee arthroplasty procedures.Main Outcomes and MeasuresThe primary outcome was mortality within 90 days. The between-group difference in mortality was estimated using cluster summary methods.ResultsA total of 23 458 patients from 31 hospitals were included, with 14 156 patients allocated to aspirin (median [IQR] age, 69 [62-77] years; 7984 [56.4%] female) and 9302 patients allocated to enoxaparin (median [IQR] age, 70 [62-77] years; 5277 [56.7%] female). The mortality rate within 90 days of surgery was 1.67% in the aspirin group and 1.53% in the enoxaparin group (estimated difference, 0.04%; 95% CI, −0.05%-0.42%). For the subgroup of 21 148 patients with a nonfracture diagnosis, the mortality rate was 0.49% in the aspirin group and 0.41% in the enoxaparin group (estimated difference, 0.05%; 95% CI, −0.67% to 0.76%).Conclusions and RelevanceIn this secondary analysis of a cluster randomized trial comparing aspirin with enoxaparin following hip or knee arthroplasty, there was no significant between-group difference in mortality within 90 days when either drug was used for VTE prophylaxis.Trial Registrationhttp://anzctr.org.au Identifier: ACTRN12618001879257

Aspirin as Thromboprophylaxis in Orthopedic Surgery: A Matter of Perspective

“…In a prespeciied secondary analysis of the CRISTAL trial, the 90-days mortality was compared. 6 Mortality occurred as often in the aspirin group as in the enoxaparin group: 1.7% versus 1.5%, respectively, indicating no beneit from one over the other.…”

“…In a prespeciied secondary analysis of the CRISTAL trial, the 90-days mortality was compared. 6 Mortality occurred as often in the aspirin group as in the enoxaparin group: 1.7% versus 1.5%, respectively, indicating no beneit from one over the other.Earlier this year, the PREVENTion of Clot in Orthopaedic Trauma (PREVENT CLOT) trial from the Major Extremity Trauma Research Consortium published their results of the randomized trial in 12,211 patients who had a fracture of an extremity that had been treated operatively or who had any pelvic or acetabular fracture. 7 Patients were randomly assigned to aspirin (81 mg twice daily) or enoxaparin (30 mg twice daily) while they were in the hospital.…”