Abstract
This study aims at developing novel vascular prostheses with a small caliber based upon the following hypothesis: biodegradable matrices that are to be absorbed into growing neointima might prevent intimal hyperplasia at the anastomotic site. Characteristics of the graft are as follows: (1) ultrafine polyester fibers were used for structural framework, and (2) two kinds of protein were used for biodegradable matrices; one is cross-linked gelatin-heparin complex for “artificial intima”, and the other heatdenatured albumin for “artificial matrix” as a presealant of the graft interstices. Six grafts, 3 mm in diameter and 4 cm long, were segmentally replaced in the carotid arteries of three mongrel dogs (mean BW 11.3kg). Five of six grafts were patent (83%) and had no thrombus macroscopically four weeks after surgery. Histological examinations revealed that neither hyperplasia nor detachment of the gelatin layer was observed in the neointima that advanced onto the luminal surface at the anastomotic site, and that the artificial matrix was converting into fibrous tissue. Scanning electron microscopy demonstrated that no fibrin layer was formed on the artificial intima in the middle of the graft. These results suggested that the artificial intima was excellent substructure for neointima and remained antithrombogenic, and that the artificial matrix had no adverse effect on the surrounding tissue. Our concept might contribute to the successful development of vascular prostheses with a small caliber.
