Obesity Does Not Influence the Outcomes of Minimally Invasive Mitral Valve Repair for Mitral Regurgitation: A Longitudinal Analysis

Objectives Data on the role of obesity in patients undergoing minimally invasive cardiac surgery are sparse, and the longitudinal observations after minimally invasive mitral valve repair (MI-MVr) in obese patients are lacking. Methods This retrospective propensity-score-matched analysis compared the outcomes of MI-MVr in obese patients (body mass index [BMI] ≥30 kg/m2), with those in individuals with normal body weight (BMI 19-25 kg/m2), focusing on overall survival. Results In 501 analysed matched pairs, BMI ranged 30-60 kg/m2 in obese group and 19-24.9 kg/m2 in normal-BMI group. There were no baseline differences among matched cohorts, except for higher incidence of hypertension (78% vs 57%, P < .001) and hypercholesterolaemia (35% vs 28%, P = .02) in obese patients, and slightly worse renal function. All patients received MI-MVr through right lateral mini-thoracotomy. The median total operative time (by 11 minutes) and cardiopulmonary by-pass time (by 5 minutes) were longer in obese patients (P = .001), but the cross-clamp times did not differ. There were no intergroup differences in the early complication rates or hospitalization lengths. After a median follow-up of 9.3 years, the overall survival was similar. Actuarial survival at 15 years was 59% for obese patients and 57% for those with normal BMI (log-rank, P = .38). A multivariable model identified diabetes (HR [95% CI], 1.65 [1.26-2.16], P = .0003), chronic lung disease (1.81 [1.31-2.51], P = .0004), left ventricular ejection fraction (LVEF) <50% (2.28 [1.78-2.93], P ≤ .0001), and older age (1.08 [1.07-1.10], P ≤ .0001) as independent predictors of mortality. Conclusions Obesity alone does not influence the outcomes of MI-MVr, but diabetes, chronic lung disease, and impaired pump function do affect the overall survival.