Cite this article as: Aljanadi F, Toolan C, Theologou T, Shaw M, Palmer K, Modi P Is obesity associated with poorer outcomes in patients undergoing minimally invasive mitral valve surgery? Eur J Cardiothorac Surg 2021;59:187–91. Is obesity associated with poorer outcomes in patients undergoing minimally invasive mitral valve surgery? Firas Aljanadi , Caroline Toolan, Thomas Theologou , Matthew Shaw , Kenneth Palmer and Paul Modi * Department of Cardiac Surgery, The Liverpool Heart & Chest Hospital, Liverpool, UK * Corresponding author. Department of Cardiac Surgery, Liverpool Heart & Chest Hospital, Thomas Drive, Liverpool L14 3PE, UK. Tel: +44-151-228-1616; fax: +44- 151-600 1246; e-mail: paul.modi@lhch.nhs.uk (P. Modi). Received 18 April 2020; received in revised form 3 June 2020; accepted 27 June 2020 Abstract 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/m 2 and BMI < 30 kg/m 2 , as per World Health Organization definitions. Baseline charac- teristics, 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 CONVENTIONAL VALVE OPERATIONS V C The Author(s) 2020. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved. European Journal of Cardio-Thoracic Surgery 59 (2021) 187–191 ORIGINAL ARTICLE doi:10.1093/ejcts/ezaa274 Advance Access publication 23 September 2020