Decade-long variation in the development of complications after cardiac surgery across the United States.

Abstract

Interhospital variation in complications after cardiac surgery may reflect differences in quality across centers. Although these differences have been observed for years, changes in variation over time have not been quantified. In the present study, we assessed trends in center-level variation of major adverse events after cardiac surgery and associations with hospital volume. Adult (≥18 years) hospitalizations entailing elective cardiac surgery (coronary artery bypass grafting, valve repair/replacement) were identified in the 2012-2021 National Inpatient Sample. Hospitals were stratified into quartiles using annual cardiac case volume. Major adverse events was defined as in-hospital mortality or any complication (cardiac, respiratory, stroke, infectious, thromboembolic, intraoperative). A hierarchical logistic regression model evaluated the variation in major adverse events attributable to hospital effects. Of 1,816,755 patients undergoing cardiac surgery, 28.5% experienced major adverse events. Rates of major adverse events decreased over the study period from 33.3% (2012) to 23.3% (2021). Variation of major adverse events attributable to hospital effects was 7.3%. Major adverse event rates decreased at centers in the greatest-volume quartile (33.5 to 22.8%) and the lowest (37.5 to 36.0%) from 2012 to 2021 (both nptrend <0.001). The overall spread in unadjusted major adverse events rate by center decreased from a standard deviation of 15.7% in 2012 to 13.0% in 2021 (nptrend <0.001). After multivariable risk adjustment, the decrease in center-level variation of major adverse events persisted (standard deviation 6.9% in 2012 to 5.6% in 2021; nptrend <0.001). Interhospital variation in major adverse events declined significantly over the decade. Future efforts should focus on underperforming centers to improve consistency in cardiac surgery outcomes.