Is low-molecular-weight heparin superior to aspirin for VTE prophylaxis?
Aspirin demonstrated a significantly higher rate of postoperative venous thromboembolic events compared with enoxaparin in this noninferiority study.
PRACTICE CHANGER
Consider low-molecular-weight heparin (LMWH) rather than aspirin to prevent postoperative venous thromboembolism (VTE) in patients undergoing total hip or knee arthroplasty for osteoarthritis.
STRENGTH OF RECOMMENDATION
B: Based on a single cluster-randomized crossover trial.1
CAVEATS
Study aspirin dosing differed from US standard
This study showed significantly lower rates of symptomatic VTE in the enoxaparin group compared with the aspirin group; however, the majority of this difference was driven by rates of below-the-knee DVTs, which are clinically less relevant.8 Also, this trial used a 100-mg aspirin formulation, which is not available in the United States.
CHALLENGES TO IMPLEMENTATION
Aspirin is far cheaper and administered orally
Aspirin is significantly cheaper than enoxaparin, costing about $0.13 per dose (~$4 for 30 tablets at the 81-mg dose) vs roughly $9 per 40 mg/0.4 mL dose for enoxaparin.9 However, a cost-effectiveness analysis may be useful to determine (for example) whether the higher cost of enoxaparin may be offset by fewer DVTs and other sequelae. Lastly, LMWH is an injection, which some patients may refuse.
