| Objectives:1. To develop domestic stent-graft as well as its delivery system, thus to assemble into totally-domestic stent-graft system. 2. To establish the animal model of aortic abdominal aneurysm (AAA) with pigs, then to examine the efficacy and safety of the endovascular treatment of experimental AAA with the totally-domestic stent-graft system. 3. To evaluate the biocompatibility between the domestic stent-graft and abdominal aorta.Methods:1. We wove into self-expanding endovascular stent with 0.4mm single wire of nitinol alloy and examine its physical performance including component, shape-restoring temperature, magnetism, tensile force, extending ratio, super-elasticity, durability , corruption speed and etc. Meanwhile, we made the graft with thickness of 0.03mm using expanding -polytetra-fluroethylene (ePTFE) and also examine its porosity, maximal aperture, blowing-intensity and lacerating force. Their biological character were also tested. Finally the nitinol stent and the ePTFE graft were tried to be felted into the stent-graft.2. The domestic delivery system was developed through material analysis, structure design and moulding. Its toxicity as well as blood-compatibility were inspected. Then the totally-domestic stent-graft system was assembled with the stent-graft and the system. Its flexility and torque-conductivity were verified via vitro test. 3. We applied artificial patch to establish a animal model of subrenal AAA with adult swine of 50kg and validated it with following CT scanning. In experimental group, we implanted the domestic stent-graft to treat the AAAs through endovascular approach via the right common femoral artery while the control group didn't undergo the endovascular treatment. The efficacy and safety of the totally-domestic stent-graft system were verified through the comparison of DSA pre and post the procedure, CT follow-up and final biopsy. 4. The specimen of experimental and control group were taken at the same time point (2, 4, 12 weeks after the operation). The histological slices underwent HE pigmentation, special pigmentation of collagen and elastin, immunohistochemistry of α actin from vascular smooth muscle cells (VSMC) and in-situ apoptosis detection. Thus we made comparison between the groups and normal abdominal aorta in intimal thickness, relative content of collagen and elastin, density and apoptosis ratio of VSMC in medium by the means of computer-assisted image analysis. Furthermore, we performed scanning of electro-microscope for the specimen of experimental group.Results:1. The nitinol self-expanding stent possess 50.8-51.8% proportion of nickel, shape-restoring temperature ranging from 28-40℃ and little magnetism. Its tensile force, extending ratio, super-elasticity, durability , corruption speed all reached or exceeded related standard. The ePTFE graft shared excellent porosity, maximal aperture, blowing-intensity and lacerating force. Meanwhile, their biological character both achieved requirement. Finally we successfully felted the nitinol stent and the ePTFE graft into the stent-graft.2. We improved the design of the delivery system for the stent-graft, which was different from that of the imported ones. The delivery system also presentd no toxicity and perfect blood-compatibility. The totally-domestic stent-graft system demonstrated favorable flexility and torque-conductivity through via vitro test.3. The animal model of subrenal AAA was successfully established in adult swines and further approved by CT scanning. In experimental group, the results of peri-procedural DSA and follow-up CT indicated the AAAs were repaired with no endoleak, no migration as well as patent renal artery and subrenal aorta after the intraluminal implantation of the domestic stent-graft. The final biopsy also showed no thrombosis and stenosis in the stent-graft with thrombosis in the aneurysmal sac. 4. Compared with the control and normal aorta, the stent-graft was covered with intimal as early as 2 weeks but suffered more severe...
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