Change in luminal diameter of the left internal thoracic artery anastomosed to the totally occluded left anterior descending coronary artery

BACKGROUND: Coronary artery bypass grafting (CABG) with a composite Y-graft made of the left internal thoracic artery (LITA) and another arterial graft has a risk for hypoperfusion. Changes over time in the diameter of the LITA anastomosed to the left anterior descending coronary artery (LAD) are not known. METHODS: Data were collected for 71 patients who had undergone coronary angiography (CAG) immediately and at 1 year following off-pump CABG with a composite Y-graft made of the LITA and either the radial artery or the right gastroepiploic artery. These patients were divided into 2 groups depending on the degree of LAD stenosis. Group 1 (n = 28) consisted of patients with complete occlusion of the LAD. Group 2 (n = 43) consisted of patients with <90% stenosis of the LAD. The clinical state and luminal diameter of the LITA on immediate postoperative and postoperative 1-year CAG were compared and analyzed. RESULTS: On the immediate postoperative CAG, mean LITA diameter of Group 1 was larger than that of Group 2 (2.09 ± 0.53 vs. 1.61 ± 0.33 mm, P = 0.01). Mean LITA diameter 1 year following CABG was also larger in Group 1 than in Group 2 (2.49 ± 0.31 vs. 2.10 ± 0.45 mm, P = 0.005). Both groups showed significant increases in the LITA diameters at postoperative 1 year. CONCLUSIONS: The LITA used as a composite Y-graft underwent remodeling, resulting in a larger diameter, to supply adequate myocardial blood. The degree of change in luminal diameter varied according to the severity of the LAD stenosis.