Growth potential of left internal thoracic artery grafts: analysis of angiographic findings

Background. The growth potential of the internal thoracic artery (ITA) is still undetermined, and little is known about the long-term effects of anastomosing it to the coronary artery. Methods. Fifty-three patients whose left ITA (LITA) had been anastomosed to the left anterior descending (LAD) coronary artery underwent coronary angiography within 1 month of operation and in late follow-up (mean interval: 4.5 ± 1.5 years). The diameter ratios of LITA to LAD were designated as the matching ratio. Results. In follow-up, the diameter of the LITA increased from 1.83 ± 0.40 to 2.46 ± 0.53 mm in the 29 patients with progressive proximal native coronary stenosis. However, late results indicate that the matching ratio did not vary according to the location of the LITA anastomosis on the LAD (proximal portion: 1.13 ± 0.16, distal portion 1.19 ± 0.13), and reached an upper limit of about 1.4. Conclusions. Growth potential of the LITA is limited by the diameter of the coronary artery onto which it is anastomosed. The most effective procedure for enhancing the growth potential of the LITA is to anastomose as proximally as possible onto the LAD.