Evaluating the Impact of Operative Team Familiarity on Cardiac Surgery Outcomes: A Retrospective Cohort Study of Medicare Beneficiaries

Objective: To associate surgeon-anesthesiologist team familiarity (TF) with cardiac surgery outcomes. Background: TF, a measure of repeated team member collaborations, has been associated with improved operative efficiency; however, examination of its relationship to clinical outcomes has been limited. Methods: This retrospective cohort study included Medicare beneficiaries undergoing coronary artery bypass grafting (CABG), surgical aortic valve replacement (SAVR), or both (CABG+SAVR) between January 1, 2017, and September 30, 2018. TF was defined as the number of shared procedures between the cardiac surgeon and anesthesiologist within 6 months of each operation. Primary outcomes were 30- and 90-day mortality, composite morbidity, and 30-day mortality or composite morbidity, assessed before and after risk adjustment using multivariable logistic regression. Results: The cohort included 113,020 patients (84,397 CABG; 15,939 SAVR; 12,684 CABG+SAVR). Surgeon-anesthesiologist dyads in the highest [31631 patients, TF median (interquartile range)=8 (6, 11)] and lowest [44,307 patients, TF=0 (0, 1)] TF terciles were termed familiar and unfamiliar, respectively. The rates of observed outcomes were lower among familiar versus unfamiliar teams: 30-day mortality (2.8% vs 3.1%, P=0.001), 90-day mortality (4.2% vs 4.5%, P=0.023), composite morbidity (57.4% vs 60.6%, P<0.001), and 30-day mortality or composite morbidity (57.9% vs 61.1%, P<0.001). Familiar teams had lower overall risk-adjusted odds of 30-day mortality or composite morbidity [adjusted odds ratio (aOR) 0.894 (0.868, 0.922), P<0.001], and for SAVR significantly lower 30-day mortality [aOR 0.724 (0.547, 0.959), P=0.024], 90-day mortality [aOR 0.779 (0.620, 0.978), P=0.031], and 30-day mortality or composite morbidity [aOR 0.856 (0.791, 0.927), P<0.001]. Conclusions: Given its relationship with improved 30-day cardiac surgical outcomes, increasing TF should be considered among strategies to advance patient outcomes.