Bilateral Internal Thoracic Artery Grafting Improves Survival for Severe Left Ventricular Dysfunction and Diabetes

Background: In patients with severe left ventricular (LV) dysfunction requiring coronary artery bypass grafting (CABG), the association between diabetic status and outcomes after surgery, as well as with survival benefit following bilateral internal thoracic artery (ITA) grafting, remain largely unknown. Methods and Results: Patients (n=188; mean [+/- SD] age 67 +/- 9 years) with LV ejection fraction <= 40% who underwent isolated initial CABG were classified into non-diabetic (n=64), non-insulin-dependent diabetic (NIDM; n=74), and insulin-dependent diabetic (IDM; n=50) groups. During follow-up (mean [+/- SD] 68 +/- 47 months), the 5-year survival rate was 84% and 65% among non-diabetic and diabetic patients, respectively (P=0.034). After adjusting for all covariates, both NIDM and IDM were associated with increased mortality, with hazard ratios (HRs) of 1.9 (95% confidence interval [CI] 1.0-3.7; P=0.049) and 2.4 (95% CI 1.2-4.8; P=0.016), respectively. Among non-diabetic patients, there was no difference in the 5-year survival rate between single and bilateral ITA grafting (86% vs. 80%, respectively; P=0.95), whereas bilateral ITA grafting increased survival among diabetic patients (57% vs. 81%; P=0.004). Multivariate analysis revealed that bilateral ITA was significantly associated with a decreased risk of mortality (HR 0.3; 95% CI 0.1-0.8; P=0.024). Conclusions: NIDM and IDM were significantly associated with worse long-term clinical outcome after CABG for severe LV dysfunction. Bilateral ITA grafting has the potential to improve survival in diabetic patients with severe LV dysfunction.