Human Greater Saphenous Vein: Histologic and Ultrastructural Variation

This study describes the varied histologic features and ultrastructure of human saphenous veins obtained from patients undergoing infrainguinal arterial reconstruction. Portions of 30 remnant veins were fixed at arterial pressure (100 mmHg). Vein specimens were obtained from 13 men and 17 women, with a mean age of 70.2 years. Ten veins (33%) were from diabetic patients. Samples of fixed veins were prepared for light and electron microscopy. The luminal surface contained valves and redundant intimal folds at the site of ligated side branches. Microvalves were present at the orifices of several 1-mm vein tributaries. The endothelial cells lining the intima were often discontinuous and were aligned in a variable pattern. The thicknesses of the vein walls varied from 20 to 360 μm, with increased connective tissue matrix in the intima and medial layers of thick-walled veins. Some 10% of the veins demonstrated spindle cells in the intima; these cells had a smooth muscle cell phenotype and varied with respect to the degree of cellular differentiation. Regions of vein wall calcification were occasionally seen and were always present in association with a thickened vein intima. Variations in the structure of the saphenous vein from patients undergoing bypass surgery are common. The relationship between altered saphenous vein morphology and subsequent vein graft stenosis needs to be defined.