Abstract
A new method to give an antithrombogenic property to collagenous biomaterials could be applied to the small caliber vascular grafts of 2.5-3.0mm in internal diameter. The graft indicated 100% patency in the carotid and femoral arteries of the experimental animals. The preparation of the graft was as follows. Fresh carotid arteries obtained from dogs were treated along the following heparinization method, 1. The carotid artery grafts were treated with a 0.01% ficin solution in 0.2M phosphate buffer, 2. Ten percent protamine solution was poured into the graft lumen to penetrate into the graft wall. 3. Being inflated with an air pressure of 100mmHg, the graft was treated with one percent glutaraldehyde solution to cross—link the protamine which had been impregnated to the graft wall and then washed with distilled water, 4. The graft was soaked into one percent heparin solution for 24 hrs at 45°C and repeatedly washed with distilled water. The heparin concentration and distribution in the grafts before and after the implantation were measured. The result indicated that the heparin was gradually released from the graft wall during the implantation period. After the release of heparin, the graft wall was covered with a layer of the endothelial cells. It can keep the graft antithrombogenicity permanently.
