Suitability of venous and arterial conduits used for coronary artery bypass grafting in conjunction with coronary disease risk factors

Background/study objectives: We studied patients undergoing coronary artery bypass grafting. Risk factors for coronary disease were studied in conjunction with the histopathologic findings of the grafts prior to implantation. Our aim was to correlate the histologic condition of the grafts and evaluate the morphological changes in conjunction with existing risk factors. Design/patients: In 10 candidates for surgical revascularization (nine males, mean age 60.8 years), the risk factor profile was studied (smoking, dyslipidaemia, hypertension, diabetes, family history) and the Body Mass Index was calculated. Of a total of 14 grafts, 10 were saphenous vein grafts and four left internal thoracic artery grafts. Histologic samples were studied under optical and electron microscopy. We studied the intima morphology and thickness, the width of the intercellular spaces, the texture of the subendothelial layer, the endothelial status, and the condition of the basal lamina. Histopathological changes were correlated with risk factors. Results: Histopathological changes were observed in the wall structure of all grafts. The most important changes were found in the venous grafts, notably: intima thickening, existence of foam cells in the intima, widening of the intercellular spaces, subendothelial oedema, degeneration and detachment of endothelial cells, and wide multilayered basal lamina. The co-existence of two or more risk factors seems to exarcerbate morphological changes. Conclusion: Morphological changes are present principally in the walls of venous but also arterial conduits, even prior to implantation. These changes may be attributable to preparation techniques and preservation conditions of the grafts, but they could additionally be induced by coexisting risk factors. It is conceivable that these alterations could perhaps precipitate and accelerate atherosclerotic changes, inducing lumen narrowing or even occlusion of the graft postoperatively.