title: Analysis of the learning curve for beating heart, totally endoscopic, coronary artery bypass grafting.
abstract: BACKGROUND
  Robotic cardiac surgery has been proved safe and feasible in dedicated centers. We systematically analyzed the learning curve issues associated with totally endoscopic coronary artery bypass grafting (TECAB) using a stepwise approach by a single surgeon who had successfully performed >650 cases of various types of robotic cardiac surgery at our single center.
  
  
  METHODS
  From January 2007 to March 2013, 230 patients underwent robotic coronary bypass grafting on the beating heart. Of these patients, 90 had successfully undergone beating heart TECAB using the da Vinci S/Si Surgical System without conversion to sternotomy. All beating heart TECAB procedures were completed using the following modules: endoscopic left internal thoracic artery (LITA) harvesting, pericardiotomy and target vessel identification, and anastomosis of the LITA to the target vessel. The perioperative outcomes were compared among 3 quintiles of 30 consecutive patients each and the learning curve results were evaluated.
  
  
  RESULTS
  No in-hospital mortality or severe morbidity occurred. The comparison among the 3 quintiles showed a significant decrease in operative time (P=.000), LITA harvesting time (P=.037), and anastomotic time (P=.000). A significant learning curve was observed for the operative time [y(min)=223-17×ln(x); r2=0.217, P=.000]; LITA harvesting time [y(min)=37-3×ln(x); r2=0.097, P=.003]; and LITA-left anterior descending artery anastomotic time [y(min)=18-2×ln(x); r2=0.298, P=.000]. No differences were found in the mean transit flow (P=.102) or perioperative complications among the 3 quintiles.
  
  
  CONCLUSIONS
  Modular-based TECAB procedures can be successfully performed; however, each module has a steep learning curve. A stable and well-trained robotic cardiac team and an experienced cardiac surgeon can achieve good, reproducible results after this substantial learning curve.
authors.affiliation: Department of Cardiovascular Surgery, Chinese People's Liberation Army General Hospital, Beijing, China.
authors.forename: Nan
authors.initials: N
authors.lastname: Cheng
authors.affiliation: Department of Cardiovascular Surgery, Chinese People's Liberation Army General Hospital, Beijing, China. Electronic address: gchq301@yahoo.com.
authors.forename: Changqing
authors.initials: C
authors.lastname: Gao
authors.affiliation: Department of Cardiovascular Surgery, Chinese People's Liberation Army General Hospital, Beijing, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Yang
authors.affiliation: Department of Cardiovascular Surgery, Chinese People's Liberation Army General Hospital, Beijing, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Department of Cardiovascular Surgery, Chinese People's Liberation Army General Hospital, Beijing, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Wang
authors.affiliation: Department of Cardiovascular Surgery, Chinese People's Liberation Army General Hospital, Beijing, China.
authors.forename: Cangsong
authors.initials: C
authors.lastname: Xiao
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002983:Clinical Competence; D017023:Coronary Angiography; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D004724:Endoscopy / Q000009:adverse effects; D005260:Female; D006801:Humans; D007387:Internal Mammary-Coronary Artery Anastomosis / Q000009:adverse effects / Q000379:methods*; D059032:Learning Curve; D008297:Male; D008875:Middle Aged; D010492:Pericardiectomy; D012307:Risk Factors; D012371:Robotics; D025321:Surgery, Computer-Assisted / Q000009:adverse effects; D013997:Time Factors; D020858:Tissue and Organ Harvesting; D016896:Treatment Outcome; D014654:Vascular Patency