Abstract Body (Do not enter title and authors here): Background
In coronary artery bypass grafting (CABG), left internal mammary artery (LIMA) grafting to the left anterior descending coronary artery is the established gold standard. However, the optimal choice and configuration for a second conduit remain a matter of debate. The right internal mammary artery (RIMA) is frequently used in this role; however, whether it provides superior outcomes as a free graft or in situ is unclear. We aimed to evaluate and compare long-term clinical outcomes between free RIMA and in-situ RIMA used as a second conduit in CABG involving LIMA grafting using a meta-analysis.
Methods:
A comprehensive literature search of PubMed and Embase was conducted through May 2025 to identify studies comparing free RIMA (fRIMA) and in-situ RIMA (isRIMA) in CABG. The primary outcomes assessed were overall mortality, graft occlusion, major adverse cardiac events (MACE), and revascularization.
Results:
A total of 13 studies were included in this meta-analysis, comparing outcomes between the use of fRIMA and isRIMA as a second conduit in patients undergoing CABG. Pooled analysis showed no statistically significant difference in overall mortality between the two groups (HR [95% confidence interval (CI)] = 0.87 [0.58-1.30]). Similarly, graft occlusion (HR [95% CI] = 1.01 [0.87-1.18]), MACE (HR [95% CI] = 1.08 [0.83-1.39]), and revascularization (HR [95% CI] = 0.81 [0.55-1.19]) were comparable between fRIMA and isRIMA.
Conclusion:
This meta-analysis demonstrated no significant differences in clinical outcomes between free and in-situ RIMA when used as a second conduit in conjunction with LIMA. These findings support the use of RIMA in either configuration, allowing surgeons procedural flexibility without compromising patient outcomes.