The challenge of achieving 1% operative mortality for coronary artery bypass grafting: A multi-institution Society of Thoracic Surgeons Database analysis

Objectives Cardiothoracic surgical leadership recently challenged the surgical community to achieve an operative mortality rate of 1.0% for the performance of isolated coronary artery bypass grafting (CABG). The possibility of achieving this goal remains unknown due to the increasing number of high-risk patients being referred for CABG. The purpose of our study was to identify a patient population in which this operative mortality goal is achievable relative to the estimated operative risk.

Results A total of 34,416 patients (average patient age, 63.9 ± 10.7 years; 27% [n = 9190] women) incurred an operative mortality rate of 1.87%. Median STS predicted risk of mortality was 1.06% (interquartile range, 0.60%-2.13%) and median surgeon CABG volume was 544 (interquartile range, 303-930) operations over the study period. After risk adjustment for the confounding influence of surgeon volume and operative year, the association between STS PROM and operative mortality was highly significant (P <.0001). More importantly, the adjusted spline function revealed that an STS PROM threshold value of 1.27% correlated with a 1.0% probability of death, accounting for 57.3% (n = 19,720) of the total study population. Further, the STS PROM demonstrated a limited predictive capacity for operative mortality for STS PROM > 25% as observed to expected mortality began to diverge.

Conclusions Achieving the goal of 1.0% operative mortality for primary, isolated CABG is feasible in appropriately selected patients in the modern surgical era. However, this goal may be achieved in only 60% of CABG patients without other improvements in processes of care. Calculated STS PROM can be used to strongly identify patients with estimated mortality risk <1.27% to achieve this goal, but it appears limited in its predictive capacity for those patients with estimated risk >25.0%. These data provide a foundation for further study to determine if 1.0% mortality for CABG is achievable nationwide.