Development of a small caliber vascular graft using a connective tissue tube with temporary antithrombogenicity

A connective tissue tube containing collagen fibrils and capillary blood vessels is an ideal material for artificial artery, since the collagen fibrils compose an excellent supporting framework for cell migration and proliferation and the endothelial cells of the capillary can be the origin of the endothelialization of the graft. However, its thrombogenicity has remained a problem. This experiment was designed to develop a small caliber (3mm) vascular graft using an autogenous connective tissue provided with temporary antithrombogenicity. A tube knitted of ultra-fine polyesters was implanted subcutaneously in the back of mongrel dogs for three weeks. Thus accomplished connective tissue grafts were heparinized ionically in vitro, using cross-link agents. Then the treated grafts, 5-6 cm in length and 3mm in diameter, were segmentally replaced with bilateral carotid arteries. During the follow-up period up to 55 days, 7 of 8 grafts (88%) were patent. Histological examinations revealed that there was no thrombus and the neointima formation with a lining of endotherial cells was completed, extending overall length of the grafts. Thus, newly devised hybrid type of connective tissue graft is thought to be usefull for a replacement for arteries with a small caliber.