Influence of Diabetes Mellitus on Long-Term Survival in Systematic Off-Pump Coronary Artery Bypass Surgery

Background Diabetic patients generally present a more diffuse and calcified coronary artery disease than nondiabetic patients that can affect long-term outcome especially if an off-pump coronary artery bybass graft (OPCABG) technique is used. The aim of this study was to compare long-term results of OPCABG surgery for diabetic and nondiabetic patients. Methods This is a retrospective analysis of prospectively gathered data over a 10-year period of 1,000 consecutive and systematic OPCABG patients operated on between September 1996 and April 2004. Average follow-up period was 66 ± 28 months and was 97% complete. Overall survival as well as occurrence of major adverse cardiac events in diabetic and nondiabetic patients were specifically studied. Results In all, 278 diabetic patients and 722 nondiabetic patients were treated. There was no difference in 30-day mortality between the two groups (p = 0.70). Diabetic patients had more postoperative acute renal insufficiency (p = 0.01) and infections (sepsis; p = 0.002), and deep sternal infections (p = 0.04) Ten-year survival (p = 0.006) and survival free of major adverse cardiac events (p = 0.02) was decreased in the diabetic group. Age (hazard ratio [HR] = 1.06), peripheral vascular disease (HR = 1.72), carotid disease (HR = 1.53), congestive heart failure (HR = 1.51), incomplete revascularization (HR = 2.37), chronic renal insufficiency (HR = 1.93), left ventricular ejection fraction (HR = 0.13), and a lesser use of multiple internal thoracic artery grafts (HR = 0.67), but not diabetes mellitus (p = 0.13) were significant determinants of long-term mortality. Similarly, peripheral vascular disease (HR = 1.92), chronic renal insufficiency (HR = 2.36), emergent operation (HR = 1.71), chronic obstructive pulmonary disease (HR = 1.76), previous percutaneous coronary intervention (HR = 1.66), left ventricular ejection fraction (HR = 0.26), ischemic mitral regurgitation (HR = 1.83), and a lesser use of multiple internal thoracic artery grafts (HR = 0.72) were determinants of decreased survival free of major adverse cardiac events but not diabetes (p = 0.2). Breaking down the major adverse cardiac events, diabetes was found an independent predictive factor of recurrent myocardial infarction (HR = 1.85) and a borderline cause of readmission for congestive heart failure (p = 0.06). Need for new revascularization was comparable for both population (p = 0.37). Conclusions In our series of OPCABG surgery patients, diabetic patients had a comparative operative mortality and perioperative myocardial infarction rate as nondiabetic patients. However, they had an increased prevalence of postoperative acute renal insufficiency and infections. They also had a worse outcome than nondiabetic patients, but that was mainly due to a higher prevalence of preoperative comorbidities and a lesser use of multiple internal thoracic artery grafts. However, diabetes itself was a potential risk factor for long-term occurrence of myocardial infarction and congestive heart failure.