Internal Mammary Artery Bypass

The mainstay for the treatment of multi-vessel severe coronary artery disease is coronary artery bypass graft (CABG) surgery. Various grafts and conduits have been used and were studied to optimize surgical outcomes. The internal mammary artery (IMA) is the gold-standard conduit and associated with significant improvement in short and long-term outcomes and survival of patients undergoing CABG surgery. The saphenous vein graft (SVG), also commonly used in CABG procedure, is prone to early atherosclerotic changes that lead to obstruction. Therefore it is considered inferior to the IMA conduit in terms of long-term patency rates. In comparison to SVGs, the long-term patency rate of IMA bypass conduits is very high, and around 90% of grafts remain free of significant stenosis at ten years. Loop . published 10-year survival of patients who received an IMA graft to the left anterior descending coronary artery with or without one or more vein grafts versus patients who received only SVGs, which showed that the survival was higher with an IMA graft (93.4%) versus SVG (88.0%) for those with the one-vessel disease, 90.0% versus 79.5% for two-vessel disease, and 82.6% versus 71.0% (P<0.0001) for those with three-vessel disease. Since then, the IMA has become the preferred choice for grafting the left anterior descending coronary artery in CABG. Specific physiological, anatomic, and hemodynamic characteristics of IMA graft make it a suitable conduit and less prone to early atherosclerotic changes. We will discuss the anatomy of IMA, the surgical technique of IMA grafting, its complications, and clinical significance.