Baseline Demographics and Operative Characteristics
A total of 1,211 patients were included in this study, 607 (50.1%) low-risk and 604 (49.9%) high-risk patients. Median age for both cohorts was 66 years, and both cohorts had similar body mass index, as well as distributions of gender and race. Both groups had similar comorbidity burden, but the low-risk group had higher prevalence of cerebrovascular disease (25.04% vs 20.20%, P=0.044). Patients in the high-risk group had higher prevalence of congestive heart failure (25.33% vs 19.77%, P=0.021) and presentation with advanced stage New York Heart Association symptoms (Class III or IV). High-risk patients also had a lower median left ventricular ejection fraction (46.5% [IQR 35.0% to 55.0%] vs 53% [IQR 40.0% to 58.0%], P<0.001) (Table 1 ).
Patients in both cohorts had equal distributions of elective, urgent, and emergent CABG. A higher proportion of patients were bridged to CABG with an intra-aortic balloon pump (15.89% vs 8.73%, P<0.001) in the high-risk group. Society of Thoracic Surgeon predicted risk of mortality was similar between cohorts. There was a higher utilization of cardiopulmonary bypass in the high-risk group (83.11% vs 70.68%, P<0.001), but median perfusion and aortic cross-clamp times were similar (Table 1 ).