Minimally invasive mitral valve surgery versus conventional sternotomy mitral valve surgery: A systematic review and meta-analysis of 119 studies

Background and Aim of the Study Whether minimally invasive mitral valve surgery (MMVS) leads to better outcomes remains unclear. We conducted a systematic review and meta-analysis comparing various MMVS approaches with conventional sternotomy. Methods We searched Cochrane CENTRAL, MEDLINE, EMBASE, ClinicalTrials. gov, and the ISRCTN Register for studies comparing minimally invasive approach (thoracotomy, port access, partial sternotomy, or robotic) with median sternotomy for mitral valve surgery. We performed title and abstract, full-text screening, and data extraction independently and in duplicate. We pooled data using random effect models. Quality assessment was performed using validated tools. Certainty of evidence was established using the GRADE framework. Results One hundred and nineteen studies (n = 38,106) met eligibility criteria: eight randomized controlled trials (RCTs) and 111 observational studies. MMVS was associated with fewer days in hospital (RCT: MD: -2.2 days, 95% CI, [-3.7 to -0.8]; observational: MD: -2.4 days, 95% CI, [-2.7 to -2.1]). Observational studies suggested that MMVS reduced transfusion requirements with fewer units transfused per patient (MD: -1.2; 95% CI, [-1.6 to -0.9]) and fewer patients transfused (RR, 0.7; 95% CI, [0.6-0.7]). Observational data also suggested lower mortality with MMVS (RR, 0.6; 95% CI, [0.5-0.7], p < .001, I-2 = 0%), but this was not corroborated by RCT data. The risk of postoperative mitral regurgitation (>= 2+ or requiring re-intervention) did not differ between the two groups. Conclusions MMVS may be associated with shorter length of hospital stay with no significant difference in short-term morbidity and mortality. There is a paucity of high-quality data on the long-term outcomes of MMVS when compared with conventional sternotomy.