Instrument Design And Experimental Research Of Vascular Prostheses' Compliance Properties In Vitro

When the arteries cannot yet work normally because of their chronic complications, for example the angiosclerosis, angioneoplasm, thrombus, dilapidation or aging, implantation of vascular prosthesis is necessary. Each year a large number of different kinds of vascular prostheses are demanded all over the world. The design and manufacturing of vascular prostheses, the structure and performance of vascular prostheses have been researched widely. But the vascular grafts developed in our country have not had some satisfied results in the clinic application. Many elements restrict the exploitation of vascular prostheses in our country. One of the astriction maybe is the lack of a study on the biomechanical performance for vascular prostheses and the reasonable test methods.The research in this paper referred to the characterizations of the vascular prostheses' compliance and the establishment of relative test methods, which is one part of the project on "characterization of biomechanical performance for vascular prostheses". The compliance is one of the most important characterization indexes of the vascular prostheses. Because there is no instrument that can be used to test the compliance of vascular prostheses in China now, we designed and manufactured the vascular prostheses' compliance test instrument based on ISO7198. This device could be used to measure the radial and longitudinal compliances of textile vascular prostheses. Through plentiful repeated experiment and statistic analysis, the test data of each sample accord with the normal distribution, and the number of sample has been decided for each test to reduce the random error. The measuring performance and the measuring procedure of the instrument were studied,and then the manipulating was given in detail.In longitudinal compliance (equivalent to the usable length) testing, we mainly discussed the test method of crimp graft. Through the analysis of the test data, it is suitable to test the longitudinal compliance by the device that we designed. In usable length test, we have noted that there are some differences between the stretching and shrinkage behaviors of wall crimps under same pressure.The influencing factors on radial compliance of the textile vascular prostheses have been studied in theory. The important influencing factors are the textile structure, wall density and diameter of the tubular sample. For the vascular prostheses, wall density and diameter of tube are different with different processes of manufacture; the radial compliance of tube varies with different processes too.In conclusion, in this paper we established the characterized index of the vascular prostheses' compliance, designed and manufactured the vascular prostheses' compliance test instrument, gave the optimal measuring method and test procedure. The variation of the compliance in every process can be measured with the instrument we designed and the measuring data can be used to evaluate the products. Some conclusions gained can be supplied as references for the foundation of the theories of vascular prostheses' design.