Venous Thromboembolism Prophylaxis Practice Patterns, Outcomes, and Risk Stratification After Surgery for IBD: A National Surgical Quality Improvement Program IBD Collaborative Study

BACKGROUND: The optimal venous thromboembolism chemoprophylaxis strategy after surgery for IBD is not defined. OBJECTIVE: To investigate the real-world efficacy of chemoprophylaxis strategies after surgery for IBD in a retrospective cohort. DESIGN: Retrospective analysis of medical records from the National Surgical Quality Improvement Program IBD Collaborative of patients treated between July 2020 to October 2023. SETTING: Seventeen medical centers. PATIENTS: Patients with IBD undergoing colectomy and/or proctectomy were included. INTERVENTIONS: Chemoprophylaxis. MAIN OUTCOME MEASURES: Thirty-day venous thromboembolism (clot) rates. RESULTS: During 3 years, 1797 patients were eligible for chemoprophylaxis and included in the analysis, of whom 44 (2.4%) developed a clot within 30 days: 50% before and after discharge, respectively. Clots were diagnosed a median of 9 days postoperatively. The most common clots were portomesenteric (39%), pulmonary embolism (27%), and upper extremity (18%). Before discharge, clot rates differed by chemoprophylaxis strategy: enoxaparin (0.57%) versus unfractionated heparin (2.1%, p = 0.006). Any extended chemoprophylaxis was used in 50.5%, and clot rates differed by strategy: no extended chemoprophylaxis (1.4%), enoxaparin (0.63%), and others (3.5%, p = 0.01). Chemoprophylaxis strategies were not associated with bleeding complications. Multivariable analysis revealed that preoperative systemic inflammatory response syndrome (p = 0.0005) and extended resections (p < 0.0001) were independent risk factors for postoperative clots. Patients with 0, 1, or 2 risk factors had clot rates of 1.2%, 4.0%, and 13.5%, respectively (p < 0.0001). Inpatient and extended prophylaxis with enoxaparin were independently associated with a lower risk of clots both before and after discharge (p = 0.002 and p = 0.02, respectively), with relative risk reductions of 74.8% and 72.6%. For a clot rate of 2.5%, the estimated number needed to treat with enoxaparin in-hospital and postdischarge was 54 and 55 patients, respectively. LIMITATIONS: The limitations to this study were generalizability and selection bias. CONCLUSIONS: After IBD surgery, venous thromboembolism chemoprophylaxis with enoxaparin was associated with a decreased risk of clot formation before and after discharge. Patients at highest risk may benefit the most from extended chemoprophylaxis.