A learning curve in aortic dissection surgery with the use of cumulative sum analysis.

ABSTRACT

This study demonstrates the risk adjusted cumulative sum analysis of an individual surgical learning curve for acute type A aortic dissection surgery. Thirty consecutive patients were operated by a single surgeon for acute type A aortic dissection from April 2001 to March 2008. Operative variables, mortality, and major morbidities were analyzed. The learning curve was calculated by cumulative sum analysis. The anticipated 30-day operative mortality rate was 20.2 +/- 12.7% (range, 3.3-56.7%) and the expected 30-day mortality and morbidity rate was 47.0 +/- 13.3% (range, 21.7-70.6%) according to the Japan SCORE calculator. The observed operative and in-hospital mortality rate was 6.67% (two patients), and the observed major postoperative morbidity rate was 10.0% (three patients). Risk-adjusted cumulative sum analysis revealed that no excess deaths occurred beginning at the seventh case and thereafter. The surgeries for acute type A aortic dissection could be performed at the professionally permissive level from the beginning. Risk-adjusted cumulative sum analysis was a useful tool to monitor the performance of the surgical procedure.