The Analysis Of Wall Structure And Properties Of Small Diameter EPTFE Vascular Prosthesis

The first factor that should be considered for an ideal vascular prosthesis is the matching of the host vessel and implanted graft. Vascular prosthesis must meet the compatibility requirements on mechanical, chemical, surface and pharmacological properties at the same time. Moreover, ePTFE is a special porous structure membrane. The difference on microstructure or topography properties of porous polymer material received more and more attention. The overseas researchers studied porous polymer prosthesis with different relative parameters widely and their conclusion showed that topography properties influenced prosthesis in vivo transplant, issue and cell growth process. There were more relative research abroad and their products manufacturing had shaped to something, but products are developed in our country and they don't have enough competitive power in clinic when compared with imported ones. Many elements restrict the exploitation of ePTFE prosthesis in our country. One of the astriction maybe is the lack of enough analysis and research on the microstructure or topography properties for ePTFE prosthesis.The main objective of this research was to evaluate and compare the different properties between small diameter ePTFE prosthesis home and abroad, and the evaluation content included microstructure or topography properties, biomechanical properties, surface and chemical properties. For the test methods, we took ISO7198, previous biomechanical properties evaluation system and analysis methods of ePTFE in material science for reference, and of course, the special shape of ePTFE prosthesis was also taken into consideration. Meanwhile we introduced cell growth experiment into the study and there goes to be a more profound evaluation.According to the designed reasonable protocol and feasible test methods, all samples had been undertaken all tests. The study also included the following work: microstructure or topography analysis on ePTFE prostheses'wall and some surface properties tests had been introduced and improved; each test method on the new mechanical test machine(multifunctional strength tester) had been learned and well-commanded; the differences between the two groups'ePTFE prostheses properties results had been found and compared. After all, the study got some meaningful results. By analysis and comparison the difference on wall microstructure between two groups (SEM pictures), the rationality of these observation methods had been proved. Some results had been found in failure lifetime, elastic recovery and first time introduced cell proliferation test. We also discussed the factors that affected the strength and failure lifetime respectively. We made the conclusion that crystallinity, geometry or morphology and microstructure or topography of wall had some relationship with strength results while elastic recovery and microstructure or topography of wall for failure lifetime.We found there are some differences between the two groups'ePTFE prostheses properties results, and namely they are microstructure or topography of wall, failure lifetime, elastic recovery and compatibility on cell proliferation. What's more, the imported prostheses all have better performance on the above mentioned properties. So there is still so much space of improvement for domestic prostheses on their manufacturing process. But we got some closer results on the properties like biomechanical performance, material composition and surface properties. When compared with textile-based samples, ePTFE prostheses'biggest weakness is their low strength.In a word, the study accomplished all properties'test and the overall evaluation. Intensively and detailed comparison and analysis had been presented on the properties difference between ePTFE prostheses home and abroad. The final results had certain reference value for the domestic products'further optimization on manufacturing and properties design.