Coronary artery bypass surgery in type 2 diabetic patients: predictors of mortality and morbidity

Abstract

Background: Coronary artery bypass grafting has been widely admitted in the therapeutic arsenal of coronary artery disease in diabetics with low morbi-mortality. However, it requires special management which may be challenging in low-volume centers especially in African countries. We aimed to analyze the outcome of coronary artery bypass graft in our diabetic population and define predictors of adverse events. Patients and methods: We retrospectively enrolled 529 consecutive diabetic patients (type 2) who underwent on-pump coronary artery bypass grafting at our institution between January 2000 and June 2018. The mean age was 61.1 ± 8.3 years with 4.04 as sex ratio (M/F) and 2.95 as mean EuroSCORE II. History of acute myocardial infarction, left main coronary artery stenosis, and three-vessel disease was present in respectively 58%, 26.1%, and 72.2% of patients. The average number of bypass was 2.4 ± 0.8. Duration of cardiopulmonary bypass and aortic cross-clamping were respectively 124.8 ± 43.5 and 79.7 ± 32.9 min. Results: In-hospital mortality was 5.9% (n = 31) and the late mortality was 6.9% (n = 32). Duration of artificial ventilation, ICU stay, and postoperative stay were respectively 7 h, 44 h, and 13 days. Postoperative complications were myocardial infarction, superficial wound infection, mediastinitis, and low cardiac output syndrome in respectively 9.1%, 25.5%, 3.8%, and 12.7% of patients. Multivariable logistic regression analysis revealed that left ventricular ejection fraction < 40% (OR = 1.88; 95% CI 1.30–2.47; p = 0.03), poor perioperative glycemic control (OR = 1.53; 95% CI 1.12–2.38; p = 0.014), intra-aortic balloon pump insertion (OR = 2.29; 95% CI 1.47–3.10; p < 0.001), and postoperative cardiac complications (OR = 2.01; 95% CI 1.23–2.78; p < 0.001) were predictors of in-hospital mortality. Predictors of mediastinitis were obesity (OR = 5.86; 95% CI 1.43–23.95; p = 0.014), inotropic drugs use (OR = 8.14; 95% CI 1.57–42.34; p = 0.013), chest reopening for bleeding (OR = 4.01; 95% CI 0.62–25.85; p = 0.014), and blood transfusion (OR = 7.56; 95% CI 1.09–52.76; p = 0.041). Follow-up was 86.1% complete, with a mean follow-up of 63.5 ± 48.3 months (1–192 months), and cumulative survival at 5, 10, and 15 years was respectively 95.5 ± 1.1%, 86.3 ± 2.9%, and 76.9 ± 6.9%. Conclusion: Even in low-volume centers in developing areas, coronary artery bypass surgery is an effective therapy for coronary artery disease in diabetic patients despite a relative high morbidity and mortality.