Which arterial graft is widely considered the best long-term conduit for the LAD and why?

• A. The right internal mammary artery; preferred due to length.
• B. The left internal mammary artery (LIMA) because it has superior long-term patency and resistance to atherosclerosis, leading to improved survival when grafted to the LAD.
• C. Saphenous vein grafts have better patency than LIMA.
• D. The radial artery is contraindicated for LAD.

Answer: (B)

Durability and patency of the conduit to the LAD determine long-term outcomes because the LAD supplies a large portion of the left ventricle. The left internal mammary artery graft to the LAD stands out because it shows superior long-term patency and is highly resistant to atherosclerosis compared with vein grafts. This enduring openness translates into fewer graft failures and improved survival after CABG when the LAD is treated with the LIMA. The artery’s natural biology—endothelial health, favorable flow dynamics, and greater adaptability to increased myocardial demand—helps it stay open for decades. Other conduits, like saphenous veins, may perform well early but are prone to restenosis and atherosclerosis over time, reducing long-term patency. The radial artery can be a good alternative in selected patients but carries risks such as vasospasm and variable long-term results, and the right internal mammary artery, while useful in some settings, does not provide the same universal durability to the LAD as the LIMA.