Morphological differences of the internal thoracic artery in patients with and without coronary artery disease--evaluation by duplex-scanning.

Objective: The internal thoracic artery is an established arterial graft for myocardial revascularisation, especially of the left anterior descending artery because of a higher patency rate compared to venous grafts. It has never been investigated, whether there are morphological differences in this vessel between patients with or without coronary artery disease or if they are comparable to morphological changes in the common carotid artery.
Methods: We investigated the internal thoracic artery and the common carotid artery of 24 patients (12 with coronary artery disease, 12 without coronary artery disease) with an ultrasonic system on both sides. The intima-media thickness and the diameter of both vessels were estimated.
Results: The intima-media-thickness of the internal thoracic artery was comparable in all patients, independent of the presence of a coronary artery disease (0.51+/-0.11 mm with coronary artery disease, 0.50+/-0.17 mm without coronary artery disease, P>0.05). Compared with this the intima-media-thickness of the common carotid artery was thicker in patients with coronary artery disease (0.84+/-0.13 mm with coronary artery disease, 0.73+/-0.07 mm without coronary artery disease, P< or or =0.014). There was no correlation between the thickness of the internal thoracic artery and the common carotid artery (r=0.018, P>0.05).
Conclusions: It could be demonstrated for the first with non-invasive ultrasound, that the intima-media-complex of the internal thoracic artery is protected of the influence of arteriosclerosis. There are no morphological differences like the intima-media-thickness of the common carotid artery. The proven protective mechanism underlines the widespread use of the internal thoracic artery as a coronary artery bypass graft.