Outcomes in patients undergoing coronary artery bypass graft surgery in the United States based on hospital volume, 2007 to 2011

Abstract

ObjectiveTo examine national trends in coronary artery bypass grafting (CABG) volume between 2007 and 2011, and analyze in-hospital outcomes after CABG surgery stratified according to hospital volume. MethodsWe analyzed all patients who underwent isolated CABG surgery between 2007 and 2011 in the National Inpatient Sample database. Trends in procedure volume and rates of adverse in-hospital outcomes were examined. Multivariate propensity-score adjusted analysis was performed to compare in-hospital mortality for hospitals based on quartiles of CABG volume. ResultsThe frequency of isolated CABG decreased by 25.4% from 2007 to 2011 (from 326 cases per million adults to 243 cases per million adults), with the most marked decline at higher-volume centers. Patients in the highest-volume quartile were more likely to have a history of previous CABG, previous percutaneous coronary intervention, peripheral vascular disease, hypertension, or chronic renal failure. In-hospital mortality was highest in low-volume centers. In multivariate logistic regression analysis, low hospital volume was an independent predictor of in-hospital all-cause mortality (adjusted odds ratio, 1.39; 95% confidence interval, 1.24-1.56; P < .001). ConclusionsThe rate of CABG procedures has declined, mainly at high-volume centers. Low CABG volume is associated with an increase in in-hospital mortality.