Arterial versus venous conduits in coronary artery bypass grafting: a systematic review with meta-analysis

Background: Coronary artery bypass grafting (CABG) remains a cornerstone of treatment for patients with multivessel coronary artery disease. While the use of the left internal mammary artery (LIMA) to the left anterior descending artery is the standard of care, the optimal choice of additional conduits—arterial versus venous—remains a subject of ongoing debate. Objectives: To compare mid- and long-term conduit patency, survival, and freedom from major adverse cardiac events (MACE) between arterial and venous conduits in CABG. Methods: We conducted a systematic review and meta-analysis of randomized controlled trials from 2000 onwards comparing arterial and venous conduits for non-LAD targets in CABG. Primary outcomes were mid- and long-term survival, angiographic patency, and freedom from MACE. Studies were appraised for risk of bias using RoB-2 and evidence certainty was evaluated using GRADE. Results: Eleven RCTs including 2,848 participants were analyzed. Mid-term survival did not differ between arterial and venous conduits (log risk ratio 0.00; 95% CI -0.03 to 0.03). Long-term survival showed a modest benefit for arterial conduits (log risk ratio 0.23; 95% CI 0.09 to 0.37; P <0.001). Arterial conduits demonstrated higher mid-term patency (log risk ratio 0.06; 95% CI 0.02 to 0.11; P =0.01), and long-term patency data from a single study also favoured arterial grafts. Freedom from MACE was similar at mid-term (log risk ratio 0.00; 95% CI -0.04 to 0.05), while long-term data suggested a small, non-significant advantage for arterial grafts. Certainty of evidence ranged from moderate to low, primarily due to observer and performance bias and limited long-term data. Conclusions: Arterial conduits offer superior mid-term patency and show a trend toward improved long-term survival, supporting their selective use beyond the LIMA-LAD graft. However, given the modest clinical differences and low-certainty long-term data, venous conduits continue to play an essential role in CABG. Further large-scale, high-quality trials are needed to define the optimal conduit strategy in contemporary surgical practice.