Modification Of Fabric For Endovascular Exclusion

With the boosting development of economy in our country, and the improvement of the living standard, the series diseases in vascular system that based on the hypertension, diabetes and arteriosclerosis has been the essential threatening to health and live of the people. In the nearly decades, the trends of surgery began directing to simple intervention and mini-traumatic. The stent-grafts are delivered intraluminaly to exclude the lesion out of the normal circulation. Thus the technique is nominated as endovascular exclusion(EVE). It has advantages of mini-traumatic, less blood transfusion, rapid resumption, less complication. In our county, through years of clinical experiences, doctors found one reason that influence the operation effect is that the stent-grafts can't be fully excluded the lesions out of the abnormal circulation. This phenomenon decreases the efficiency of the operations and more over, it can deteriorate the effect if there is blood between the graft and abnormal vessel wall.So, this paper is to modify the surface of the fabric for endovascular exclusion (EVE) to let the blood between the stent-graft and lesion immediately coagulate when they first touch. In order to do so we must immobilize the coagulant substance firmly onto the surface of the fabric. Considering that the fabric can not directly link firmly with the coagulant substance, in order to find the possible methods of immobilizing coagulant substance-thrombin onto the surface of the fabric for EVE. we must firstly graft some materials with specific functions onto the fabric's surface, and then make use of their special functions to further immobilize the coagulant substance onto the surface of the fabric with covalent bond. Following these thought in mind, we adopted twodifferent ways of surface modification: Low-Temperature-Plasma and UV irradiation, to graft some high polymer or monomer with specific functions onto the surface of the fabric. Then making use of the specific functions of the modified surface, immobilize some coagulant substance like thrombin onto the modified fabric's surface. Thus when the stent-graft is grafted into human blood vessel, the blood between the stent-graft and lesion will coagulate when it touches the thrombin on the fabric's surface. So to assure the curative effect of endovascular exclusion(EVE).As to graft some materials with special functions onto the fabric's surface, this paper gives detailed analysis and comparisons using GPT-3 plasma instrument,and self-made device for UV irradiation . Electric scan pictures and infrared spectrogram proved the possibilities of these two methods, also it proved the plasma method's graft ratio is a little lower; the UV irradiation method has a higher graft ratio and so the fabric's surface will graft more monomers with specific functions. This paper has also made some grope for the methods of further immobilizing coagulant thing like thrombin onto the modified surface, taken the blood texts of some experiments' results, pointed out the possible problems of the groping methods and also pointed out the direction of farther study in this biomoiecules' immobilization .