Histologic examination of the clipped internal thoracic artery by transmission electron microscope in patients undergoing coronary artery bypass grafting

Objectives: As we known that the internal thoracic artery (ITA) has an excellent patency rate in coronary artery bypass grafting (CABG). However, early graft failure due to occlusion and spasm is still the major problem after coronary artery bypass surgery. We examined histopathologic findings of the clipped internal thoracic artery (ITA) in patients undergoing CABG using transmission electron microscope (TEM). Methods: To investigate the histopathololojic ITA examination, 60 patients were randomly selected. The ITA was harvested in a standart fashion with the use of low voltage electrocotery and its distal end was cut prior to bifurcation and clipped. Just before the ITA anastomosis 1 mm lenght of ITA ring was cut and saved in 2.5% Glutaraldehide solution for fixation and examination of transmission electron microscope (TEM). One blinded anatomopatholog examined all specimens and described the endothelial integrity according to the score system proposed by Fischlein et al. Results: In ten cases (17.5%) different degree of histopathologic findings (endothelial cells, intercellular and intracellular organels and adventitia) were recorded The most important histopatholojic findings of ITA were as follows: endothelial vacuolisation, intimal thickening and/or intimal seperation, subendothelial edema, swallowing of cytoplasma and mitocondria. Conclusion: Our results showed that the endothelial pathology is high when the ITA clipped. Unfortunataly, because our study did not include the non-clipped ITA we have not concluded the comparison or statistical results. In our opinion, for absolute definition of the effects of the clipping the ITA it should be planned the comparative results between the clipped and non-clipped ITA histologic examinations.