Neo-arterial walls of Dacron vascular prostheses were examined under both optical and electron microscopes from 1 to 1184 days after implantation in the thracic aorta of 146 dogs.
Complete endothelialization of the grafts was observed in all specimens of more than 20 weeks after implantation and no fibrin layer nor thrombus was deposited on them. The essential structure of the neo-arterial wall could be divided into four laminae:
(1) the most inner coat, the tunica intima, whose structural elements resembled the endothelium of an aorta, serving to inhibit the formation of thrombi;
(2) the next coat, a smooth muscle cells layer;
(3) the third coat, the tunica media, which consisted of a foreign body (Dacron fibers) granuloma at an end stage, served for forming the conduit framework of neoarterial walls;
(4) the outer coat, a loose connective tissue layer, which was the medium surrounding the neo-arterial walls and neighbouring organs. It resisted the local mechanical stress.
These observations revealed the fundamental structure of neo-arterial walls at stable stage, which was one of cellulofibrous tissues, quite similar to the cellulofibrous thickening of intima at arteriosclerosis.
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