Outcomes of Trainees Performing Coronary Artery Bypass Grafting: Does Resident Experience Matter?

Abstract

Outcomes after coronary artery bypass graft surgery (CABG) are known to be dependent on attending surgeon volume, but the impact of resident experience is unknown. Our objective was to assess the influence of resident experience to understand the learning curve for CABG. From 2008 to 2014, all isolated on-pump CABG (n= 1,668) during which a resident performed the entire operation (including sternotomy, mammary artery harvest, coronary anastomoses, and closure) were reviewed. Operations were stratified by individual resident CABG experience. Primary outcomes included operative time, which was further divided into "opening time" (incision to bypass initiation), cardiopulmonary bypass times, cross-clamp times, and "closing times" (bypass termination to close). Secondary outcomes included 30-day mortality and major complications. Operative time was 29.7 minutes longer (p < 0.001) during residents' first 30 CABG, primarily driven by longer opening and closing times. After controlling for resident, attending physician, preoperative risk, number of grafts, and redo status, the completion of 30 operations improved operative time by 25 minutes (p < 0.001), the majority of which included opening time (13 minutes, p < 0.001). Minor differences in bypass and cross-clamp times were not clinically meaningful, and there were no differences in 30-day mortality or major complications with respect to resident experience. Total operative time during CABG is dependent on resident experience, with significant improvement by approximately the 30th case. Importantly, these differences do not translate into worse outcomes. These data support trainees performing all components of CABG-even early in the residency experience.