Dynamic Reassessment of Pulmonary Embolism Risk after Metabolic-Bariatric Surgery

Background: Pulmonary embolism (PE) after metabolic-bariatric surgery (MBS) is rare but catastrophic. Current approaches to extended chemoprophylaxis rely primarily on discharge-based risk assessment, although post-discharge emergency department (ED) encounters and serious complications may identify additional patients at risk. Study Design: Using the MBSAQIP 2020–2024 dataset, we evaluated 2 MBSAQIP-derived discharge prediction models for post-discharge PE and examined whether reassessment after ED encounters and/or serious complications improved event identification. Secondary analyses evaluated deep venous thrombosis and composite venous thromboembolism (VTE). Results: Among 949,289 patients, 1,050 developed post-discharge PE, including 820 events (78.1%) after postoperative day 7. Discharge-only prediction models identified few subsequent PE events; the revised calculator identified 83 PEs (7.9%). Incorporating post-discharge ED encounters or serious complications identified an additional 193 PEs (18.4%), increasing total identified events to 265 (25.2%). However, 785 PE events (74.8%) occurred without identifiable discharge predictors, ED encounters, or serious complications. Composite VTE demonstrated similar performance, with 603 of 2,770 events (21.8%) identified and 78.2% occurring outside both predictive signals. Conclusions: Post-discharge PE after MBS is uncommon but largely unpredictable using current risk-stratification approaches. Discharge-based calculators identified fewer than 10% of subsequent PE events. Reassessment after ED encounters or serious complications improved identification of patients at risk but still failed to capture most patients who subsequently developed VTE.