Minimally invasive mitral valve surgery: a systematic review and meta-analysis

The mitral valve has been traditionally approached through a median sternotomy. However, significant advances in surgical optics, instrumentation, tissue telemanipulation, and perfusion technology have allowed for mitral valve surgery to be performed using progressively smaller incisions including the minithoracotomy and hemisternotomy. Due to reports of excellent results, minimally invasive mitral valve surgery has become a standard of care at certain specialized centers worldwide. This meta-analysis quantifies the effects of minimally invasive mitral valve surgery on morbidity and mortality compared with conventional mitral surgery and demonstrates equivalent perioperative mortality (1641 patients, odds ratio (OR) 0.46, 95% confidence interval 0.15-1.42, p=0.18), reduced need for reoperation for bleeding (1553 patients, OR 0.56, 95% CI 0.35-0.90, p=0.02) and a trend towards shorter hospital stays (350 patients, weighted mean difference (WMD) -0.73, 95% CI -1.52 to 0.05, p=0.07). These benefits were evident despite longer cardiopulmonary bypass (WMD 25.81, 95% CI 13.13-38.50, p<0.0001) and cross-clamp times (WMD 20.91, 95% CI 8.79-33.04, p=0.0007) in the minimally invasive group. Case-control studies show consistently less pain and faster recovery compared to those having a conventional approach. Data for minimally invasive mitral valve surgery after previous cardiac surgery are limited but consistently demonstrate reduced blood loss, fewer transfusions and faster recovery compared to reoperative sternotomy. Long-term follow-up data from multiple cohort studies are also examined revealing equivalent survival and freedom from reoperation. Thus, current clinical data suggest that minimally invasive mitral valve surgery is a safe and a durable alternative to a conventional approach and is associated with less morbidity.