Objectives: To critically review the learning curve, safety issues and outcome of a single surgeon while starting up minimally invasive mitral valve surgery (MIMVS).
Methods: We performed a descriptive, retrospective study of 138 patients with minimally invasive mitral valve surgery between March 2004 and December 2010. The learning curve was assessed using a logarithmic curve-fit regression analysis of the cardiopulmonary bypass parameters and defined as the end of the steepest part. Complexity was assessed by the number of different techniques performed on the mitral valve and the number of concomitant procedures. Follow-up was obtained for embolic events, endocarditis, bleeding, reintervention, echocardiographic data and NYHA class.
Results: The learning curve was found in the last 30 cases. There was a significant reduction in aortic cross-clamp time before and after the end of the learning curve [Patients 1-30: 120.77 (±28.28); Patients 31-138: 97.57 (±5.66); P <0.0001]. Operations during the learning curve did not correlate with intensive care unit (ICU) [1.77 (±0.97) vs 2.06 (±1.38)] and hospital stay [10.00 (±2.74) vs 9.10 (±3.36)]. In 104 patients, the valve was reconstructed, whereas in 34 it was replaced. The complexity of mitral valve reconstruction gradually increased and proportion of mitral valve replacement decreased, partly by expanding minimally invasive mitral valve surgery indications. Eighteen patients underwent 25 concomitant procedures and four conversions were necessary (after Patient 30). Minimal follow-up was 1 year with a mean follow-up of 1211 ± 651 days. No procedure-related mortality was encountered and mitral regurgitation after mitral valve repair was classified as Grade 1 or less in 101 of 104 patients at the end of follow-up.
Conclusions: Implementation of new equipment and techniques is challenging. However, minimally invasive mitral valve surgery with the endoclamp system is safe even during the learning curve. During our evolution from simple reconstructions/replacements to complex valve surgery with concomitant procedures, we could safely optimize our technique without mortality. A longer aortic cross-clamp time during the learning curve did not result in longer ICU and hospital stay.
Keywords: Learning curve; Minimally invasive; Mitral valve.
© The Author 2014. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.