Analysis of the Learning Curve in Mitral Valve Replacement Through the Right Anterolateral Minithoracotomy Approach: A Surgeon's Experience with the First 100 Patients

Abstract

Background: To apply the cumulative sum (CUSUM) failure analysis to assess the performance of a single surgeon during mitral valve replacement via the right anterolateral minithoracotomy (RAMT) approach and to analyse the learning curve for the procedure.

Methods: A total of 100 mitral valve replacements were performed using the RAMT approach from June 2011 to April 2013 by a single surgeon with no prior experience of this technique. Patients were divided into five blocks according to the operation date. The perioperative data were collected prospectively and analysed using descriptive statistics and CUSUM failure analysis.

Results: No significant differences in the background factors among the five periods were observed, except for a small increase in patient age from periods 1 to 5 (p=0.004). The surgeon's performance improved with time; a decrease in the cross-clamp time, operative time, and blood loss was observed (p<0.001). However, no significant difference in the number of failed cases was observed among the periods. All failure cases were evaluated by the CUSUM failure analysis and the CUSUM curve reflected a learning curve associated with this new procedure. The surgeon crossed the lower 80% boundary after about 33 operations, which indicates that better results can be obtained after this point.

Conclusions: Minimally invasive mitral valve surgery using the RAMT approach can be performed by a new surgeon. Furthermore, CUSUM curve analysis is a simple statistical method to implement continuous individual performance monitoring.

Keywords: Anterolateral minithoracotomy; Cumulative sum analysis; Learning curve; Mitral valve replacement; Quality control.