Aim: A small number of left internal thoracic artery (LITA) grafts are occluded at 3 years after the operation or show more than 50% stenosis of the lumen. The purpose of this study is to examine factors related to the morphology of the wall and to the function of the cell population of LITA grafts before implantation, in order to evaluate their quality and the viability, in a follow-up examination.
Methods: Fifteen LITA grafts were examined with light microscopy, for their morphology, endothelial cell coverage, apoptosis and cell proliferation, scanning electron microscopy and transmission electron microscopy.
Results: Increase of the thickness of the intima (14.21+/-1.28 mm), mean thickness of media 160.37+/-11.97 mm, detachment of intima from media, presence of foam cells in the media, low endothelial coverage (40.638+/-16.864), increase of apoptosis in intima (46.38+/-13.46), sub-intima (29.3+/-8.54), media (34.91+/-6.05) and adventitia (40.21+/-5.36), blood cells penetration of the intima through disruptions between endothelial cells are findings of LITA grafts before implantation. Cell proliferation was not detected in the wall of any graft. Follow-up examination 6 months and 2.5 years after the operation showed normal function of LITA grafts.
Conclusions: Besides of the wall injury and the initiated atherosclerotic lesions, LITA grafts are well functioning at the time of the follow-up examination. Maybe our findings are related to the later occlusion of the referred in the literature small number of LITA grafts.