Analysis of the learning curve for beating heart, totally endoscopic, coronary artery bypass grafting

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.

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.

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.

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.