ABSTRACT: Background The degree of hospital-level variation in the ratio of percutaneous coronary interventions to coronary artery bypass grafting procedures (PCI:CABG) and the association of the PCI:CABG ratio with clinical outcome are unknown. Methods and Results In a multicenter population-based study conducted in Ontario, Canada, we identified 44 288 patients from 19 institutions who had nonemergent diagnostic angiograms indicating severe multivessel coronary artery disease (2013-2017) and underwent a coronary revascularization procedure within 90 days. Hospitals were divided into tertiles according to their adjusted PCI:CABG ratio into low (0.70-0.85, n=17 487), medium (1.01-1.17, n=15 275), and high (1.18-1.29, n=11 526) ratio institutions. Compared with low PCI:CABG ratio hospitals, hazard ratios (HRs) for major adverse cardiac and cerebrovascular events were higher at medium (HR, 1.19; 95% CI, 1.14-1.25) and high ratio (HR, 1.21; 95% CI, 1.15-1.27) hospitals during a median 3.3 (interquartile range 2.1-4.6) years follow-up. When interventional cardiologists performed the diagnostic angiogram, the odds of the patient receiving PCI was higher (odds ratio, 1.37; 95% CI, 1.23-1.52) than when it was performed by noninterventional cardiologists, after accounting for patient characteristics. Having the diagnostic angiogram at an institution without cardiac surgical capabilities was independently associated with a higher risk of major adverse cardiac and cerebrovascular events (HR, 1.07; 95% CI, 1.02-1.11), death (HR, 1.09; 95% CI, 1.02-1.18), and myocardial infarction (HR, 1.10; 95% CI, 1.03-1.17). Conclusions Patients undergoing diagnostic angiography in hospitals with higher PCI:CABG ratio had higher rates of adverse outcomes, including major adverse cardiac and cerebrovascular events, myocardial infarction, and repeat revascularization. Presence of on-site cardiac surgery was associated with better survival and lower major adverse cardiac and cerebrovascular events.
