Predictors, causes, and consequences of conversions in robotically enhanced totally endoscopic coronary artery bypass graft surgery

Abstract

Background: Totally endoscopic coronary artery bypass graft surgery (TECAB), using the da Vinci telemanipulator, has become a reproducible operation at dedicated centers. As in every endoscopic operation, conversion is an important and probably inevitable issue.

Methods: We performed robotic TECAB in 326 patients (age, 60 years; range, 31 to 90 years); 242 were single-vessel and 84 were multivessel TECAB.

Results: Forty-six of 326 patients (14%) were converted to a larger incision (minithoracotomy, n = 5; sternotomy, n = 41). Left internal mammary artery injury (n = 7), epicardial injury (n = 4), balloon endoocclusion problems (n = 7), and anastomotic problems (n = 18) were common reasons for conversions. Conversion rate was significantly less for single-vessel versus multivessel TECABs (10% versus 25%; p = 0.001). Non-learning-curve case (7% versus 21%; p < 0.001) and transthoracic assistance (11% versus 22%; p = 0.018) were associated with lower conversion rates. In multivariate analysis, learning-curve case was the only independent predictor of conversion (p = 0.005). Conversion translated into increased packed red blood cell transfusion in the operating room (3 versus 0 units; p < 0.001), longer ventilation time (14 versus 8 hours; p < 0.001), and intensive care unit stay (45 versus 20 hours; p = 0.001). Hospital mortality was 0.6% in this series, with 1 patient in the conversion group (2.2%) and 1 patient in the nonconverted group (0.4%; not significant). Five-year survival was 98% in nonconverted patients and 88% in converted patients (p = 0.018). There was no difference in freedom from angina or freedom from major adverse cardiac and cerebral events.

Conclusions: Conversion in TECAB is primarily learning curve-dependent and associated with increased morbidity, but does not significantly affect hospital mortality. Both nonconverted and converted patients show good long-term survival, which is comparable to patients undergoing open sternotomy coronary artery bypass grafting. Long-term freedom from angina or freedom from major adverse cardiac and cerebral events is not influenced by conversion.