Autogenous Veins as Arterial Substitutes

Abstract

A study has been performed in dogs to further clarify the histologic fate of autogenous vein grafts used to replace segments of arteries. Special attention has been given to the morphology of autogenous vein graft endothelium. In 26 dogs, a 6 cm segment of abdominal aorta was excised and replaced with a composite graft consisting of a 3 cm segment of autogenous vein anastomosed to a 3 cm segment of Dacron. The Dacron graft was interposed between the proximal aorta and the vein to determine if vein endothelium could be demonstrated growing into the Dacron. It was reasoned that a demonstration of such growth would prove that autogenous vein graft endothelium had retained its viability. The dogs were followed for periods ranging from one week to six months before sacrifice. Hautchen preparations, designed to delineate a single layer of endothelium for en face examination, were made from the lining of the vein and Dacron grafts and adjacent segments of proximal and distal aorta. Routine histologic sections of the autogenous vein grafts were stained with H & E and stains to delineate muscle, fibrous tissue, elastic fibers, and ground substance. Specimens from 24 dogs were satisfactory for study. Autogenous vein graft endothelium, as visualized in Hautchen preparations, remained intact in all specimens and appeared only slightly altered. Endothelial growth from the vein grafts into the Dacron was demonstrated in all specimens in which the Dacron graft was incompletely lined with endothelium. A study of routine histologic sections showed that other cellular elements of the vein grafts persisted without evidence of degeneration. There was, however, an increase in fibrous tissue and ground substance, muscular hypertrophy, and some separation of the elastic fibers.