Disparities in Cardiovascular Risk Factors in Northern Plains American Indians Undergoing Coronary Artery Bypass Grafting

Objectives: Heart disease is the leading cause of death in American Indians (AIs). For AI patients with severe coronary artery disease requiring coronary artery bypass graft (CABG) surgery, little data exist. The purpose of this study was to evaluate short-term outcomes of Northern Plains AI undergoing CABG and identify variations in patient presentation. Methods: All patients undergoing isolated CABG between June 2012 and June 2017 were studied. Seventy-four AI and 1236 non-American Indian (non-AI) patients were identified. Risk factors, preoperative characteristics, cardiac status, procedural information, and outcomes were collected. Univariate analysis comparing short-term clinical outcomes between AI and non-AI populations was performed. Multivariable logistic regression models were constructed and outcome differences assessed. Unadjusted Kaplan–Meier survival estimates were produced using 5-year survival data. Results: AI patients presented with increased risk factors, including higher rates of diabetes mellitus (AI 63.5% vs. non-AI 38.7% p=< 0.001) and smoking/tobacco use (AI 60.8% vs. non-AI 20.0% p=> 0.001). Seventy-nine percent of AI patients resided on or near federal reservations and presented from rural locations. Internal mammary artery (IMA) graft use in both groups was high (AI 95.9% vs. non-AI 94.9% p=0.904), and multiarterial grafting with left internal mammary artery and radial artery use was common in both groups (AI 67.6% vs. non-AI 69.6% p=0.814). No significant differences in unadjusted 30-day mortality or short-term outcomes were detected. Adjusted Kaplan–Meier survival curves were similar between race groups up through 5 years after CABG (p-value=0.38). Conclusion: AIs presented with significantly more risk factors for cardiovascular disease compared with the general population, with especially high rates of insulin-dependent diabetes and active tobacco use. Despite this, outcomes were similar between groups. In propensity-matched groups, AIs were at decreased risk for prolonged length of stay and combined morbidity/mortality. In contrast to previous reports, AI racial identity did not adversely affect survival up to 5 years after CABG.