Is obesity associated with poorer outcomes in patients undergoing minimally invasive mitral valve surgery?

OBJECTIVES High body mass index (BMI) makes minimally invasive mitral valve surgery (MIMVS) more challenging with some surgeons considering this a contraindication. We sought to determine whether this is because the outcomes are genuinely worse than those of non-obese patients. METHODS This is a retrospective cohort study of all patients undergoing MIMVS ± concomitant procedures over an 8-year period. Patients were stratified into 2 groups: BMI ≥ 30 kg/m2 and BMI ˂ 30 kg/m2, as per World Health Organization definitions. Baseline characteristics, operative and postoperative outcomes and 5-year survival were compared. RESULTS We identified 296 patients (BMI ≥30, n = 41, median 35.3, range 30–43.6; BMI <30, n = 255, median 26.2, range 17.6–29.9). The groups were well matched with regard to baseline characteristics. There was only 1 in-hospital mortality, and this was in the BMI < 30 group. There was no difference in repair rate for degenerative disease (100% vs 96.3%, P > 0.99 respectively) or operative durations [cross-clamp: 122 min interquartile range (IQR) 100–141) vs 125 min (IQR 105–146), P = 0.72, respectively]. There were only 6 conversions to sternotomy, all in non-obese patients. There was no significant difference in any other perioperative or post-operative outcomes. Using the Kaplan–Meier analysis, there was no significant difference in 5-year survival between the 2 groups (95.8% vs 95.5%, P = 0.83, respectively). CONCLUSIONS In patients having MIMVS, there is insufficient evidence to suggest that obesity affects either short- or mid-term outcomes. Obesity should therefore not be considered as a contraindication to this technique for experienced teams.