What is the role of minimally invasive mitral valve surgery in high-risk patients? a meta-analysis of observational studies

Background Minimally invasive valve surgery is related to certain better postoperative outcomes. We aimed to assess the role of minimally invasive mitral valve surgery in high-risk patients. Methods A systematic literature review identified eight studies of which seven fulfilled criteria for meta-analysis. Outcomes for a total of 1,254 patients (731 were conventional standard sternotomy and 523 were minimally invasive mitral valve surgery) were submitted to meta-analysis using random effects modeling. Heterogeneity and subgroup analysis with quality scoring were assessed. The primary end point was early mortality. Secondary end points were intraoperative and postoperative outcomes and long-term follow-up. Results Minimally invasive mitral valve surgery conferred comparable early mortality to standard sternotomy (p = 0.19); it was also associated with a lower number of units of blood transfused (weighted mean difference, -1.93; 95% confidence interval [CI], -3.04 to -0.82; p = 0.0006) and atrial fibrillation rate (odds ratio, 0.49; 95% CI, 0.32 to 0.74; p = 0.0007); however, cardiopulmonary bypass time was longer (weighted mean difference, 20.88; 95% CI, -1.90 to 43.65; p = 0.07). There was no difference in terms of valve repair rate (odds ratio, 1.51; 95% CI, 0.89 to 2.54; p = 0.12), and the incidence of stroke was significantly lower in the high-quality analysis with no heterogeneity (odds ratio, 0.35; 95% CI, 0.15 to 0.82; p = 0.02; χ2, 1.67; I2, 0%; p = 0.43). Conclusions Minimally invasive mitral valve surgery is a safe and comparable alternative to standard sternotomy in patients at high risk, with similar early mortality and repair rate and better postoperative outcomes, although a longer cardiopulmonary bypass time is required.