Improving long term outcome for diabetic patients undergoing surgical revascularization by use of the radial artery conduit: a propensity matched study

Background: Diabetes predicts worse outcomes after coronary artery bypass grafting (CABG) We hypothesized that a strategy using radial artery (RA) conduit(s) would improve outcomes and long term survival for diabetic patients undergoing CABG with Left Internal Thoracic Artery (LITA) and RA grafts, with or without additional saphenous vein (SV) when compared with outcomes for patients bypassed with LITA and SV but no RA. Methods: A propensity matched study of long term survival in diabetic patients who had isolated first time CABG from January 1995 to June 2010 at an urban academic medical center in New York City. Our primary endpoint was all cause mortality determined from the Social Security Death Index in December 2010. Results: We compared our 15 year outcomes in diabetic patients after isolated, primary CABG: 642 patients received LITA + RA +/-SV (RA group) vs. 1201 patients who had LITA + SV only (SV group). Propensity scoring for multiple preoperative and operative variables matched 409 patients from each group: 68% were male with an average age of 61 years and ejection fraction averaged 47%. Average grafts per patient was 3.7 for both groups with 2.3 arterial grafts per patient for the RA group. Operative (30 day) mortality was 0.1% RA vs. 1.9% SV, (p < 0.0001) For propensity matched patients, mortality was 0.25 RA vs 0.5% SV. (p < 0.001) The incidence of major complications was similar in both groups. Kaplan Meier actuarial survival at 1, 5, 10 and 12 years was 98%, 89%, 77 and 70% for RA vs. 96%, 87%, 64% and 59% for SV (p < 0.006.) By Cox multivariate analysis significant predictors of mortality were: age, stroke, peripheral vascular disease, COPD, creatinine > 2.5mg/dl and low ejection fraction but only RA use predicted better survival [HR 0.683, CI 0.507-0.920, p = 0.0122]. Conclusion: For diabetic patients having CABG with LITA, use of radial artery conduit adds a substantial and sustained survival advantage compared to LITA and vein. Optimal revascularization for diabetics with multi vessel disease is redefined.