Impact of Obesity on Outcomes after Minimally Invasive Mitral Valve Surgery: A Systematic Review and Meta-Analysis

Background: Minimally invasive mitral valve surgery (MIMVS) is increasingly used as an alternative to conventional sternotomy for patients with mitral valve pathologies. This systematic review and meta-analysis aimed to evaluate whether obesity (BMI ≥30 kg/m²) is associated with different perioperative and postoperative outcomes in patients undergoing MIMVS. Methods: MEDLINE, EMBASE, and Cochrane Library were systematically searched to identify studies comparing outcomes between BMI groups in patients undergoing MIMVS. The primary outcome was in-hospital mortality. The secondary outcomes were stroke, re-exploration for bleeding, intensive care unit (ICU) length of stay (LOS), hospital LOS, postoperative atrial fibrillation (POAF), requirement of permanent pacemaker implantation (PPI), duration of mechanical ventilation, and wound complications. A random-effects model was performed. Results Six studies comprising 5,925 patients met the inclusion criteria. Compared with BMI <30 kg/m², obesity was not associated with higher in-hospital mortality (RR 1.29; 95%CI 0.67 to 2.48; p=0.446; I²=31.6%). However, obese patients had significantly higher rates of postoperative atrial fibrillation (RR 1.28; 95%CI 1.12 to 1.46; p<0.001; I²=0%), longer intubation duration (MD 0.88; 95%CI 0.11 to 1.65; p=0.02; I²=35.7%), longer hospital LOS (MD 0.51; 95%CI 0.04 to 0.99; p=0.03; I²=82.3%), and higher requirement for permanent pacemaker implantation (RR 1.43; 95%CI 1.01 to 2.01; p=0.043; I²=0%). No significant differences were observed in stroke, ICU LOS, re-exploration for bleeding, or wound complications. Sensitivity analyses confirmed the robustness of the pooled estimates. Conclusions In patients undergoing MIMVS, obesity was associated with higher rates of POAF and modestly prolonged postoperative recovery, without increased in-hospital mortality.