Improvement And Experimental Research On An In Vitro Simulating Vascular Prostheses' Compliance Testing Instrument

When human blood vessels cannot work normally because of arteriosclerosis, thrombus, dilapidation or aging of vascular, implantation of vascular prostheses is necessary. Vascular prostheses products made in China are unable to meet the clinical application demand very well in nowadays, a very important reason is lacking of vascular prostheses' biomachanical properties research, which has restricted our deveploping of vascular prostheses products. As one of the most important characterization indexes of vascular prostheses' biomachanical properties, vascular compliance property's measure methods and technologies are even absent in our country, so our research group developed an in vitro simulating vascular prostheses' compliance testing instrument after summarized the characteristics and defects of almost all compliance testing instuments both at home and abroad.The main reseach task in this thesis is the improvement of the vascular prostheses' compliance testing instrument. It can simulate human in vivo environment, especially simulating human artery blood pressure waveform originated with it, but the newly developed instrument is not perfect, for example it can simulate only one kind of human artery blood pressure waveform steadily, it's unable to discretionarily zoom the waveform in the testing software that induced experimenter can not check the influence on the pressure waveform by environmental factors, the elastic silicon tube inside of the vascular prostheses prototype is too thick, and there are only two diameter size, it's too far to meet the demand of testing all vascular prostheses' with quite different diameter.Inorder to overcome all kinds of defects, the instrument has been greatly improved: firstly, based on the pressure waveforms superimposing principle, by changing the cycle pipeline settings and accessories, a new "liquid-liquid" pressure waveform superimposing mode has been developed, which displaced the original "liquid-gas" pressure waveform superimposing mode, finally, two kind of steady human artery blood pressure waveforms have been successfully simulated; secondly, a new testing software has been developed, overcame the defects of the original software, besides, a new option of seting data acquiring rate has been added; thirdly, more thin PU tubes with better compliance property and more diameter sizes have been made, which have greatly improved the sample holder. After improving of the instrument, error analysis of the instrument has been taken through plentiful repeated experiments and data anlysis, which proved the improved instrument is very stable. In addition, experiment of measuring compliance of several vascular prostheses has been carried out, and a conclusion has been drew: the pressure waveform, material and structure of vascular prostheses all can influence the compliance testing result.In conclusion, the pressure waveform simulating method, software and hardware of the compliance testing instrument has been greatly improved, so does the instrument experimental performance; what's more, the compliance of same vascular prostheses prototype tested under human artery blood pressure waveform is obviously distinct from that tested under the same pressure range triangular pressure waveform; furthermore, the material and structure mostly decide vascular prostheses' compliance property.