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Updated: Jun 15, 2025
Author Spotlight: Enhancing Coronary Artery Revascularization
Published on: September 15, 2023
Secondary Conduits in Coronary Artery Bypass Grafting Surgery
Austin Browne1, Shun Fu Lee2, Fraser Rubens3
1Population Health Research Institute and Hamilton Health Sciences, Hamilton, Ontario, Canada.
Insights
Radial arteries as a secondary graft in coronary artery bypass grafting (CABG) surgery show better outcomes than veins. The right internal mammary artery (RIMA) use requires further investigation due to limited data.
Area of Science:
- Cardiovascular Surgery
- Thoracic Surgery
- Vascular Surgery
Background:
- Growing evidence suggests the right internal mammary artery (RIMA) may be linked to poorer clinical outcomes in coronary artery bypass grafting (CABG).
- The optimal choice for a secondary arterial conduit after CABG remains a critical clinical question.
Purpose of the Study:
- To compare the clinical outcomes of using the right internal mammary artery (RIMA) versus radial artery versus saphenous vein as a secondary conduit in CABG surgery.
- To evaluate the impact of different secondary graft choices on mortality, myocardial infarction, stroke, and revascularization rates.
Main Methods:
- A post-hoc analysis of the CABG Off or On Pump Revascularization Study.
- Inclusion of 3913 patients from 79 centers across 19 countries who underwent CABG with at least two arterial grafts.
- Assessment of all-cause mortality, myocardial infarction, stroke, and revascularization as primary outcomes.
Main Results:
- Radial arteries as a secondary conduit were associated with reduced all-cause mortality compared to veins (HR, 0.79; 95% CI, 0.64-0.98).
- The right internal mammary artery (RIMA) as a secondary conduit showed an increased risk of all-cause mortality compared to veins (HR, 1.37; 95% CI, 1.13-1.68).
- Multiple arterial grafting, regardless of conduit type, demonstrated similar mortality risks compared to single arterial grafting (HR, 0.87; 95% CI, 0.73-1.03).
Conclusions:
- Supplementing left internal mammary artery grafts with radial arteries improves clinical outcomes compared to vein grafts.
- Insufficient data on RIMA use prevents definitive conclusions regarding its role in multiple arterial grafting.
- A randomized controlled trial is warranted to clarify the optimal use of RIMA in CABG surgery.
Background:
Recent evidence has suggested use of the right internal mammary artery (RIMA) is associated with worse clinical outcomes in patients undergoing coronary artery bypass grafting (CABG) surgery. Therefore, we compared the clinical consequences of secondary conduit selection (RIMA vs radial artery vs saphenous vein) after CABG.
Methods:
A post-hoc analysis of the CABG Off or On Pump Revascularization Study, involving 3913 patients from 79 centers in 19 countries who underwent CABG surgery and received arterial grafting with at least 2 grafts. Outcomes of interest were all-cause mortality, myocardial infarction, stroke, and revascularization.
Results:
A total of 3913 patients received veins (3210; 68%), radial arteries (549; 12%), or RIMAs (154; 3%) to supplement left internal mammary artery to left anterior descending artery grafts. The risk of all-cause mortality was reduced in patients who received secondary radial arteries compared with veins (weighted hazard ratio [HR], 0.79; 95% CI, 0.64-0.98) and increased in patients who received RIMA compared with veins (weighted HR, 1.37; 95% CI, 1.13-1.68) after 4.8 years of follow-up. Multiple and single arterial grafting had a similar mortality risk (weighted HR, 0.87; 95% CI, 0.73-1.03).
Conclusions:
Supplementing left internal mammary artery to left anterior descending artery grafting using radial arteries led to better clinical outcomes than veins, and too few RIMA were available to draw definitive conclusions. A randomized trial is needed to clarify the role of the RIMA in multiple arterial grafting CABG surgery.
