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Browne et al. Vessel Plus 2024;8:19 Vessel Plus
DOI: 10.20517/2574-1209.2023.126

Review Open Access

Selecting conduits for coronary artery bypass

grafting: caution regarding the right internal
mammary artery

1
Austin Browne , André Lamy 1,2,3
1
Population Health Research Institute and Hamilton Health Sciences, Hamilton, ON L8L 2X2, Canada.
2
Department of Surgery, McMaster University, Hamilton, ON L8S 4L8, Canada.
3
Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, ON L8S 4L8, Canada.
Correspondence to: Dr. André Lamy, Population Health Research Institute and Hamilton Health Sciences, DBCVSRI Room C1-
112, 20 Copeland Avenue, Hamilton, ON L8L 2X2, Canada. E-mail: lamya@mcmaster.ca
How to cite this article: Browne A, Lamy A. Selecting conduits for coronary artery bypass grafting: caution regarding the right
internal mammary artery. Vessel Plus 2024;8:19. https://dx.doi.org/10.20517/2574-1209.2023.126

Received: 19 Sep 2023 First Decision: 5 Mar 2024 Revised: 15 Mar 2024 Accepted: 17 Apr 2024 Published: 25 Apr 2024

Academic Editor: Frank W. Sellke Copy Editor: Fangyuan Liu Production Editor: Fangyuan Liu

Abstract
This narrative review summarizes the angiographic and clinical outcome results of the most common coronary
artery bypass grafting (CABG) conduits. The left internal mammary artery is the preferred first conduit to bypass
the left anterior descending artery due to superior long-term survival and graft patency. Recent studies suggest the
radial artery may be the preferred second conduit for the circumflex or right coronary artery territories, challenging
the belief that the right internal mammary artery is the best choice. Despite their historical high failure rates,
saphenous vein grafts continue to be widely used as secondary conduits. Several recent studies report suboptimal
rates of right internal mammary artery graft failure, with clinical outcomes comparable to or worse than saphenous
veins. The suboptimal rates of RIMA graft failure may be attributed to several factors such as improvements in vein
graft failure rates, the use of in situ and non-left anterior descending artery grafting configurations, and skeletonized
harvesting techniques. While observational studies favor multiple over single arterial grafting, randomized studies
are needed for confirmation. The ongoing Randomized comparison of the clinical Outcome of single vs. Multiple
Arterial grafts (ROMA) trial aims to determine if multiple arterial grafting reduces major adverse cardiovascular
events and mortality and how secondary conduit selection influences these outcomes. Greater adoption of arterial
grafting strategies is likely to come from high-quality evidence of benefit and safety from ongoing and future large
pragmatic trials.
Keywords: Coronary artery bypass grafting, left internal mammary artery, right internal mammary artery, radial
artery, saphenous vein graft, multiple arterial grafting

© The Author(s) 2024. Open Access This article is licensed under a Creative Commons Attribution 4.0
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