Propensity-Matched Comparison of Two Different Access Modes for Minimally Invasive Mitral Valve Surgery

Mitral valve surgery is being performed routinely using minimally invasive operative techniques. We aimed comparing perioperative and long-term outcomes of minimally invasive mitral valve surgery using 2 different surgical approaches, partial upper sternotomy (PUS) vs right anterolateral minithoracotomy (RAT). From January 1998 through December 2015, 1006 patients underwent mitral valve surgery using a minimally invasive access in our institution. Logistic regression analysis was used to identify covariates among 18 patient variables including the type of mitral valve surgery. Using the significant regression coefficients, each patient's propensity score was calculated, allowing selectively matched subgroups of 243 patients each. Results are based on the matched cohorts between the 2 groups. The PUS approach was performed by 8 surgeons whereas the RAT approach by 2. PUS led to slightly longer duration of the cross-clamp time (100 ± 28 vs 88 ± 26 minutes, P < 0.001) whereas ventilation time (9 ± 37 vs 11 ± 66 hours, P < 0.001) was shorter in PUS than in RAT group. Besides the number of pacemaker implants (PUS: 6.6% vs RAT: 0.4, P = 0.0005) and postoperative chest tube drainage amount at 24 hours (PUS: 556 ± 557 mL/24 h vs RAT: 716 ± 580 mL/24 h, P < 0.001) no differences between the 2 groups regarding further perioperative outcome were observed. Long-term survival and freedom from mitral valve reintervention were comparable between the 2 groups at 6- and 8 years' follow-up. Minimally invasive mitral valve surgery can be performed safely using a PUS or RAT approach without any differences regarding perioperative and long-term morbidity and mortality. Although the RAT approach may be cosmetically more appealing in female patients, PUS may facilitate both safe performance of mitral valve surgery and resident training.