Efficacy of multiple arterial coronary bypass grafting in patients with diabetes mellitus

OBJECTIVES: Use of the left internal mammary artery in patients with diabetes mellitus and multivessel coronary artery disease is known to improve survival after coronary artery bypass grafting (CABG); however, the survival benefit of multiple arterial grafts (MAGs) in diabetic patients is debated. We investigated the efficacy of CABG performed with MAGs in diabetic patients. METHODS: The overall patient group comprised 2618 consecutive patients who underwent isolated CABG at our hospital between 1990 and 2014. Perioperative characteristics, in-hospital outcomes and long-term outcomes were compared between diabetic (n = 1110) and non-diabetic patients (n = 1508). The long-term outcomes of diabetic and non-diabetic patients were analysed between those who received a single arterial graft (SAG) and those who received MAGs. Both full unmatched patient population and propensity-matched patient population analyses (diabetic cohort = 431 pairs, non-diabetic cohort = 577 pairs) were performed. RESULTS: Preoperative comorbidities were much more common in the diabetic patients than in the non-diabetic patients; however, comorbidities were not associated with in-hospital outcomes (diabetes versus non-diabetes group, in-hospital mortality: 2.2 vs 1.5%; deep sternal wound infection: 2.2 vs 1.8%, P > 0.05). Although survival and freedom from major cardiac and cerebrovascular events (MACCEs) at 15 years were lower in the diabetes group than in the non-diabetes group (survival: 48.6 vs 55.0%, P = 0.019; MACCE-free survival: 40.8 vs 46.1%, P = 0.02), cardiac death-free survival at 15 years was similar (81.7 vs 83.9%, P = 0.24). Overall, 12-year survival was higher in both diabetic and non-diabetic patients treated with MAGs than in those treated with an SAG (64.9 vs 56.8%, P = 0.006, and 71.9 vs 60.5%, P < 0.001). Propensity-matched patient cohort analysis revealed improved 12-year survival with MAGs versus SAG in both the diabetes group (64.9 vs 58.8%, P = 0.041) and non-diabetes group (71.4 vs 63.8%, P = 0.014). Similarly, MACCE-free survival was improved in both groups. CONCLUSIONS: A long-term survival advantage, with no increase in perioperative morbidity, is conferred with the use of multiple arterial bypass grafts not only in non-diabetic patients but also in diabetic patients.