Purpose: Venous thromboembolic events (VTEs) are a major cause of morbidity following abdominopelvic oncologic surgery. Enoxaparin, a subcutaneous injectable low molecular weight heparin, is commonly used for extended-duration VTE prophylaxis (EP), but has been associated with noncompliance. Newer direct oral anticoagulants have not been prospectively studied in the urologic oncology post-discharge setting. We aimed to improve compliance with EP following abdominopelvic oncologic surgery and secondarily test the hypothesis that apixaban is noninferior to enoxaparin for EP.
Materials and methods: A single-center prospective quality improvement study measuring patient compliance and safety with EP was conducted between August 10, 2020 and September 21, 2021. Baseline data were continuously collected for 6 months, followed by a uniform departmental change from enoxaparin to apixaban. The duration of data collection was determined a priori using a noninferiority sample size estimation (145 per group). The primary outcome was compliance events (real or potential barriers to EP use). The secondary outcome was 30-day post-discharge safety events (symptomatic VTE or major bleed).
Results: A total of 161 patients were discharged with enoxaparin (baseline period) and 154 with apixaban (intervention period). Safety events occurred in 3.1% vs 0% of patients receiving enoxaparin and apixaban, respectively. The absolute risk difference of 3.1% (95% CI: 0.043%-5.8%) met the prespecified noninferiority threshold (p=0.028 for apixaban superiority). Compliance events occurred in 33.5% of enoxaparin patients and 14.3% of apixaban patients (p=0.0001).
Conclusions: There were fewer compliance events using apixaban for EP than enoxaparin after urologic oncology surgery. Regarding safety, apixaban is noninferior to enoxaparin and may in fact have fewer associated major complications.
Keywords: apixaban; factor Xa inhibitors; patient safety; postoperative complications; quality improvement.