The Obesity Paradox in Patients Undergoing Surgical Repair of Degenerative Mitral Regurgitation

Background: The obesity paradox describes the beneficial influence of an elevated body mass index on health outcomes. Currently, few studies have evaluated BMI and its impact on survival following surgical repair of degenerative mitral regurgitation (MR). Methods: Between 2004 and 2021, 1214 patients underwent surgical mitral valve repair at our institution for MR due to myxomatous degeneration. Results: Patient age was 63.2 ± 12.3 years, 341 (28%) were female, and 678 (55%) were either overweight or obese (body mass index ≥ 25 kg/m2) preoperatively. Concomitant coronary revascularization was performed in 152 (13%). Clinical and echocardiographic follow-up averaged 4.5 years and was complete for all patients. Perioperative mortality occurred in 4 (0.3%). Ten-year survival, freedom from recurrent MR ≥ 2+, and freedom from recurrent MR ≥ 3+ was 75.1 ± 2.3%, 85.8 ± 2.1%, and 96.6 ± 1.0%, respectively. A higher body mass index was associated with better survival (hazard ratio 0.99, 95% CI 0.98–0.99, p = 0.02) after adjusting for age, sex, preoperative LV function, and preoperative LV size. Conclusions: A higher BMI was associated with better long-term survival independent of age, gender, LV function, and LV size. These data may provide nuanced risk prognostication in patients undergoing surgical mitral repair.