Racial Disparities Following Coronary Artery Bypass Grafting

Study Questions:

Do black patients have higher observed and risk-adjusted mortality and morbidity following isolated coronary artery bypass grafting (CABG) in contemporary clinical practice? And, if these differences exist, to which degree are these ascribed to patient characteristics, socioeconomic factors, and overall differences in hospital and surgeon quality?


This was a retrospective analysis of data from the Society of Thoracic Surgeons Adult Cardiac Surgery Database (STS ACSD). The authors evaluated procedural outcomes on white and black patients undergoing isolated CABG between 2010 and 2011 at 663 participating STS sites. Data were adjusted for patients’ clinical and socioeconomic features, hospital and surgeon effects, and care processes (internal mammary artery graft and perioperative medication use).


Blacks patients (n = 11,697) constituted 7.9% of the total CABG study population (148,059 patients). Blacks were more likely to have comorbid conditions (e.g., hypertension, diabetes, smoking, and peripheral and cerebrovascular disease); use of immunosuppressive medications; and preoperative dialysis. Adverse presenting features such as myocardial infarction within 7 days of surgery, congestive heart failure, lower left ventricular ejection fraction, and moderate to severe mitral regurgitation were also more common among blacks. Unadjusted mortality and major morbidity rates were higher in blacks than in whites and persisted after adjusting for surgeon, hospital, and care processes in addition to patient and socioeconomic factors (odds ratio [OR], 1.17; 95% confidence interval [CI], 1.00-1.36; and OR, 1.26; 95% CI, 1.19-1.34).


Even after accounting for patient comorbidities; socioeconomic status; and surgeon, hospital, and care factors, the risks of procedural mortality and morbidity after CABG were higher among black compared with white patients.


This is a valuable study that corroborates others’ findings that black patients have higher morbidity and mortality after CABG compared with white patients. A major contribution from this analysis is that this disparity persists not only after adjusting for demographic and clinic factors, but also after accounting for provider- and hospital-related differences. Future studies should explore factors that may explain differences in CABG outcomes.

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