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.