Abstract:

BACKGROUND: After various types of vein grafts are implanted in the body, due to the incompatibility of blood vessels with artificial surface and slow venous blood flow, low pressure, it is easy to lead to intravascular thrombosis
OBJECTIVE: To study a new way to immobilize the heparin molecule on the expanded polytetrafluoroethylene (ePTFE) graft’s surface and to evaluate its anticoagulation effect by replacing the canine inferior vena cava.
METHODS: Chitosan molecule with photoallergic radical was firstly immobilized to the surface of ePTFE graft, secondly heparin was immobilized to the chitosan molecule under acid condition. Thus the ePTFE graft’ surface was immobilized with a layer of heparin molecule. Local canines’ vena cava was replaced with control and experiment ePTFE grafts. Angiography from the femoral vein and scanning electron microscope (SEM) observation were performed.
RESULTS AND CONCLUSION: All canines’ vena cava which was replaced with untreated ePTFE grafts was thrombosed since the first week after operation, while the canines’ vena cava which was replaced with ePTFE grafts immobilized with heparin kept unobstructed until the fourth week after operation. SEM observation found that mass of platelets, red blood cells and fibrin deposited on the untreated grafts’ surface, while seldom blood components could be observed on the grafts’ surface which were immobilized with heparin. ePTFE graft which surface is immobilized with heparin has an excellent anticoagulant ability, and it is an ideal venous graft in clinical usage.