Thromboxane production in umbilical vein grafts

Umbilical vein grafts were placed in the carotid arteries of sheep and removed after 10 or 90 days for determination of in vitro production of 6-keto-PGF1 alpha and thromboxane B2 (TxB2) in the anastomoses and in the middle of the grafts. At both intervals the grafts produced much more TxB2 than carotid arteries, but no significant difference in production of 6-keto-PGF1 alpha was found between grafts and carotid arteries. The strongly decreased 6-keto-PGF1 alpha/TxB2 ratio indicates a low resistance to platelet adhesion and aggregation, which may be a contributory cause of the thrombogenicity of vascular grafts and may possibly be involved in the pathogenesis of neointimal fibrous hyperplasia.