Angiographic Outcome of Coronary Artery Bypass Grafts: The Radial Artery Database International Alliance

Background: We used a large patient-level data set including 6 angiographic randomized controlled trials (RCTs) on coronary artery bypass conduits to explore incidence and determinants of coronary graft failure. Methods: Patient-level angiographic data of 6 RCTs comparing long-term outcomes of the radial artery and other conduits were joined. Primary outcome was graft occlusion at maximum follow-up. The analysis was divided as (1) left anterior descending coronary (LAD) distribution and (2) non-LAD distribution (circumflex and right coronary artery). Mixed-model multivariable Cox regression including all baseline characteristics with stratification by individual trials was used to identify predictors of graft occlusion. Results: Included were 1091 patients and 2281 grafts, consisting of 921 left internal mammary arteries, 74 right internal mammary arteries, 710 radial arteries, and 576 saphenous veins. All left internal mammary arteries were used on the LAD, the other conduits were used on the non-LAD distribution. Mean angiographic follow up was 65 ± 29 months. Occlusion rates were 2.3% for the left internal mammary arteries, 13.5% for the left internal mammary arteries, 9.4% for the right internal mammary arteries, and 17.5% for the saphenous veins. At multivariable analysis, type of conduit used, age, female sex, left ventricular ejection fraction of less than 0.50, and use of the Y graft were significantly associated with graft occlusion in the non-LAD distribution. Conclusions: Our analyses showed that failure of the left internal mammary arteries-to-LAD bypass is a very uncommon event. For the non-LAD distribution, the nonuse of radial artery, age, female sex, left ventricular ejection fraction of less than 0.50, and use of the Y graft configuration were significantly associated with midterm graft failure.