The learning curve of robotic coronary arterial bypass surgery: A report from the STS database

BACKGROUND: There is limited data to inform minimum case requirements for training in robotically assisted coronary artery bypass grafting (RA-CABG). Current recommendations rely on nonclinical endpoints and expert opinion.

OBJECTIVES: To determine the minimum number of RA-CABG procedures required to achieve stable clinical outcomes.

METHODS: We included isolated RA-CABG in the Society of Thoracic Surgeons (STS) registry performed between 2014 and 2019 by surgeons without prior RA-CABG experience. Outcomes were approach conversion, reoperation, major morbidity or mortality, and procedural success. Case sequence number was used as a continuous variable in logistic regression with restricted cubic splines with fixed effects. Outcomes were compared between operations performed earlier versus later in case sequences using unadjusted and adjusted metrics.

RESULTS: There were 1195 cases performed by 114 surgeons. A visual inflection point occurs by a surgeon's 10th procedure for approach conversion, major morbidity or mortality, and overall procedural success after which outcomes stabilize. There was a significant decrease in the rate of approach conversion (7.7% and 2.5%), reoperation (18.9% and 10.8%), and major morbidity or mortality (21.7% and 12.9%), as well as an increase in the rate of procedural success (72.9% and 85.3%) with increasing experience between groups. In a multivariable logistic regression model, case sequences of >10 were an independent predictor of decreased approach conversion (odds ratio [OR]: 0.27; 95% confidence interval [CI]: 0.09-0.84) and increased rate procedural success (OR: 1.96; 95% CI: 1.00-3.84).

CONCLUSIONS: The learning curve for RA-CABG is initially steep, but stable clinical outcomes are achieved after the 10th procedure.