There is a lack of unequivocal evidence basis for selecting the best second conduit in coronary artery bypass grafting (CABG). We thus aimed to perform head-to-head relative effect estimate on angiographic outcomes for second conduits, including the right internal mammary artery (RIMA), radial artery (RA), right gastroepiploic artery (RGEA) and saphenous vein graft (SVG) by means of network meta-analysis of randomized controlled trials (RCTs).