Major Adverse Cardiac Events After Gastric Bypass vs Sleeve Gastrectomy

Importance: Metabolic bariatric surgery is the most effective and durable treatment for weight loss and improvement of cardiovascular diseases. With sleeve gastrectomy now surpassing gastric bypass as the most common procedure worldwide, comparing these procedures' associations with major adverse cardiac events (MACE) is needed. Objective: To compare the risk of MACE among individuals undergoing gastric bypass or sleeve gastrectomy. Design, Setting, and Participants: This population-based, inverse probability-weighted cohort study was conducted using administrative claims data from Switzerland among adults undergoing gastric bypass or sleeve gastrectomy for obesity treatment between January 2012 and December 2022. Inpatient individuals with a primary or secondary discharge procedure code for gastric bypass or sleeve gastrectomy were eligible for inclusion. Data were analyzed from April 2024 to September 2025. Exposure: Gastric bypass vs sleeve gastrectomy. Main Outcomes and Measures: A weighted cohort was analyzed to study the primary outcome of 4-point MACE, including acute myocardial infarction, ischemic stroke, hospitalizations for heart failure, and all-cause mortality. Secondary outcomes were the individual components of MACE, surgical reinterventions, and associated complications. Results: Of 39 067 patients, 30 270 patients (77.5%) underwent gastric bypass and 8798 patients (22.5%) underwent sleeve gastrectomy. Median (IQR) patient age was 42 (35-50) years, and 28 560 patients (73.1%) were women. A total of 23 708 patients (60.7%) had a body mass index (calculated as weight in kilograms divided by height in meters squared) of 40 or higher. After weighting, over a median (IQR) follow-up of 5.1 years (2.6-7.6), the primary outcome occurred in 577 patients in the gastric bypass group (1.9%) and 264 patients in the sleeve gastrectomy group (3.0%), with incidence rates of 3.96 and 5.10 per 1000 patient-years, respectively (hazard ratio HR, 0.75; 95% CI, 0.64-0.88). This difference was primarily driven by lower rates of acute myocardial infarction (HR, 0.63; 95% CI, 0.46-0.86). No differences were observed in ischemic stroke, hospitalization for heart failure, and all-cause mortality. Both short- and long-term secondary outcomes favored gastric bypass over sleeve gastrectomy, except for higher rates of revision surgery and immediate postoperative complications. Conclusions and relevance: In this inverse probability-weighted cohort study, for patients undergoing metabolic bariatric surgery, gastric bypass was associated with lower rates of MACE than sleeve gastrectomy over a follow-up period of up to 11 years. Known postoperative complications were confirmed for both gastric bypass and sleeve gastrectomy.