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

Abstract

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.

Keywords

• Diabetes mellitus
• Coronary artery bypass grafting surgery
• Low-volume center
• Low-income countries
• Africa