"Extended Thromboprophylaxis with Aspirin versus Rivaroxaban after Total Hip or Knee Arthroplasty". The New England Journal of Medicine. Published online.
Clinical Question
Does extended prophylaxis with aspirin have noninferior effectiveness compared with rivaroxaban in the prevention of symptomatic venous thromboembolism (VTE) after discharge in patients undergoing total hip or knee arthroplasty?
Bottom Line
Extended thromboprophylaxis with aspirin was noninferior to rivaroxaban for the prevention of symptomatic VTE after initial postoperative rivaroxaban prophylaxis in patients who underwent total hip or knee arthroplasty.
Major Points
Venous thromboembolism is a common complication after total hip or knee arthroplasty. While direct oral anticoagulants, such as rivaroxaban, are commonly used for VTE prophylaxis post-surgery, aspirin has been proposed as a potentially effective and more affordable alternative. This randomized controlled trial demonstrated that aspirin had similar effectiveness to rivaroxaban in preventing symptomatic VTE when given for an extended duration post-surgery after an initial five-day course of rivaroxaban.
Guidelines
Evidence-based guidelines recommend postoperative anticoagulant prophylaxis for at least 14 days after total hip or knee arthroplasty. This study supports the use of aspirin as a secondary prevention strategy for VTE.
Design
- Multicenter, double-blind, randomized, controlled trial
- N=3,424 patients undergoing total hip or knee arthroplasty
- Intervention: Initial rivaroxaban (10 mg once daily) up to postoperative day 5, followed by aspirin (81 mg daily)
- Comparison: Continued rivaroxaban (10 mg once daily)
- Mean follow-up of 90 days
Population
- Patients undergoing elective unilateral primary or revision hip or knee arthroplasty
- Excluded those with hip or lower limb fracture within the previous 3 months and with metastatic cancer
Interventions
- Initial in-hospital prophylaxis with rivaroxaban (10 mg once daily), followed by random assignment to continued rivaroxaban or aspirin for an additional 9 days after knee arthroplasty or 30 days after hip arthroplasty
Outcomes
- Primary effectiveness outcome: Symptomatic VTE (proximal deep-vein thrombosis or pulmonary embolism)
- Primary safety outcome: Major or clinically relevant nonmajor bleeding
Criticisms
- The trial did not start both therapies immediately postoperative, so could not compute absolute event rates for thromboembolic or bleeding complications.
- Due to timing, some events occurred before the start of trial medication and were included in the primary analysis.
Funding
- Supported by the Canadian Institutes of Health Research
Further Reading
- The full text of the trial is published on The New England Journal of Medicine's website. Additional protocol, supplementary appendix, and disclosure forms are available as supplementary materials.