Time-Varying Survival Benefit of Radial Artery Versus Vein Grafting: A Multiinstitutional Analysis

Background A survival benefit of radial artery use versus saphenous vein grafting in coronary artery bypass grafting (CABG) has been reported. We aimed to elucidate the relative radial artery survival benefit as a function of time after surgery from two independent CABG series. Methods We compared 0- to 15-year survival with radial artery versus saphenous vein grafting in isolated, nonsalvage primary CABG with left internal thoracic artery to left anterior descending from two institutions: Ohio (radial artery [n = 2,361; 61 years]; saphenous vein [n = 2,547; 67 years]), and New York (radial artery [n = 1,970; 58 years]; saphenous vein [n = 2,974; 69 years]). Separate multivariate radial artery–use propensity models based on demographic, preoperative factors, intraoperative variables, and completeness of revascularization data were computed and used to derive propensity- and sex-matched CABG cohorts (1,799 [Ohio] and 995 [New York] pairs). A three-phase (early and late) mortality model was fit to Kaplan-Meier mortality estimates and used to derive relative radial artery versus saphenous vein hazard functions. Results Radial artery use patterns and patient risk profiles differed substantially for New York and Ohio, with the New York radial artery cohort significantly younger and more male. Within-institution matched graft-type cohorts were well matched. Cumulative mortality was significantly better for radial artery at both institutions ( p < 0.001 both). All mortality-time data were well described by the three-phase model, and the derived relative hazard functions were qualitatively and quantitatively similar for New York and Ohio, exhibiting maximal benefit between 0.5 and 5 years. Conclusions Despite substantial differences in radial artery use patterns during a 15-year period, our analysis in large propensity-matched radial artery and saphenous vein cohorts yielded remarkably similar, time-varying radial artery to saphenous vein survival benefit at both institutions. These converging findings based on two independent patient series extend currently available objective evidence in support of a radial artery survival advantage in CABG.