Time-varying survival benefit of radial artery versus vein grafting: a multiinstitutional analysis

Abstract

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.