Human saphenous veins were obtained during coronary artery bypass surgery. The segments were contracted with phenylephrine and relaxed with carbachol to determine the endothelial-dependent relaxation. The vein segments were fixed in 10 % buffered formalin and grown for 14 d in high-serum culture and then fixed in formalin. The fixed tissues were stained with Verhoeff-Van Gieson, and the average intimal and medial thicknesses were calculated using light microscopy and a computerized image analysis system.
The human saphenous veins displayed varying amounts of basal intimal thickness (range 18.80-241.3 ¦Ìm). The endothelial-dependent relaxation of the veins was highly variable, with values ranging from 0 % to 27.59 % . Human saphenous veins with a basal intimal thickness greater than 120 ¦Ìm had significantly less endothelial-dependent relaxation (8.90 % ?¡À?6.32 % ) than those with a basal intimal thickness less than 120 ¦Ìm (21.97 % ?¡À?10.64 % ). Endothelial dysfunction correlated with a basal intimal thickness greater than 120 ¦Ìm (P?=?0.02). The basal intimal thickness also correlated with increased intimal thickness after 14 d in organ culture (P?=?0.0001).
A basal intimal thickness greater than 120 ¦Ìm is a predictor of endothelial dysfunction. Also, because a greater basal intimal thickness correlated with an increased intimal thickness after organ culture, the basal intimal thickness might predict vein graft failure owing to intimal hyperplasia.