Histological study of arterial and venous grafts before their use in aortocoronary bypass surgery.

INTRODUCTION: In this study we investigated the morphology of grafts from the internal thoracic artery and the great saphenous vein, before their use in aortocoronary bypass surgery, in order to draw conclusions concerning their suitability and viability.
MATERIAL AND METHODS: Sections of grafts from the great saphenous vein and left internal thoracic artery obtained for use in bypass surgery were examined using light microscopy and transmission and scanning electron microscopy.
RESULTS: The histological changes in the walls of the vessels were classified as acute or chronic. The acute lesions concerned the endothelium and the subendothelial layer. There was extensive necrosis of endothelial cells, resulting in the basement membrane being left uncovered and becoming the target of blood cells. The endothelial necrosis was accompanied by subendothelial oedema and focal destruction of the inner elastic lamina of the internal thoracic artery. The chronic lesions affected mostly the venous grafts and included the presence of distinct atheromatous plaques or thickening of the intima and media.
CONCLUSIONS: The combination of ischaemic and chronic atheromatous lesions in bypass grafts may contribute to a decrease in their viability, especially in the case of venous grafts.