Research On Method Of Central Arterial Pressure Acquisition And Influence Factor Based On Peripheral Arterial Pressure Waveform

Cardiovascular disease(CVD)is the primary threat of human life and health.Central arterial pressure(CAP)is an effective independent predictor of CVD.Invasive cardiac catheterization method can accurately measure CAP,but its traumatic limits the clinical application.Clinically,carotid artery signal is often usedto replace the central aorta signal,and then CAP is estimated,but there is no skeletal structure under the carotid artery,which leads to the difficulty of signal acquisition.So there is a certain technical dependence.Relatively speaking,radial artery signal is easy to be measured,so CAP can be estimated from radial artery signal by generalized transfer function(GTF),and this method is widely used in clinic.GTF has been verified and used in foreign population,and the GTF built in SphygmoCor system was constructed through the frequency domain method.However,GTF has not been built in Chinese population;In addition,the generation influence factors of GTF have always been a research focus in the industry.So constructing GTF in Chinese population and studying generalization of GTF will be quite significance for noninvasive estimation of CAP.In view of this,the research on method for acquisition of GTF and influence factor based on peripheral arterial pressure waveform is made as follows:(1)The method for acquisition of CAP based on carotid artery waveform:In order to reduce the influence of noise to the pulse signal feature extraction,firstly,we compared three various filters,Butterworth filter was adopted to deal with the noise of the pulse signals finally.Butterworth filter has flat passband and fast stopband attenuation characteristics.Secondly,cubic spline interpolation function method was used to obtain carotid artery average pressure waveform,and waveform analysis techniques was used to extract the waveform characteristics,then CAP and other central blood flow indexes were calculated.Finally,we also studied the effect of sampling frequency on the calculation results of the pulse waveform parameters.The results showed that lower sampling frequency which under the satisfy Nyquist sampling theorem had no significant effect on the accuracy of the calculation results of pulse waveform parameters.This conclusion provided certain theoretical support for development and application of wearable low sampling frequency cardiovascular function test instrument.(2)The method for constructing GTF based on Fourier transform:We constructed GTF from carotid artery to radial artery based on Fourier transform.Our research objects were 80 healthy subjects,whose waveform quality of radial artery and carotid artery waveforms were quite good.The construction group and validation group of GTF had 30 people and 50 people respectively.We successfully synthesized center arterial pressure waveform from radial artery pulse wave,and the validity and accuracy of the GTF was tested in the validation group.The results showed that GTF can accurately estimate CAP,and the mean difference between measured and estimated had no clinical significance.The construction of GTF laid a solid foundation for further research generalization of GTF.(3)The effects of central artery waveform morphology on GTF:A total of 92 study subjects who had no significant cardiovascular disease were recruited in this study,then they were divided into group A(A-type waveform)and group C(C-type waveform),and MTFA(group A),MTFc(group C)and the GTF of whole subjects were built.The research found that CAP can be accurately estimated by GTF.But a specific morphology of transfer function can improve the indexes calculation results for those depend on the wave shape details.It showed that building transfer function according to morphology-appropriate can improve the accuracy of the center blood flow indexes.In conclusion,in this paper,we constrcuted GTF from carotid artery to radial artery based on Fourier analysis method.Not only GTF can calculate CAP from the radial artery signal which is easy to get access,but also it can reconstruct center arterial pressure waveform for extracting multiple center hemodynamic indexes.Furthermore,this paper found that morphology-appropriate transfer function can significantly improve the accuracy of the detail characteristics of reconstructed waveform.The research achievements provided theoretical and technical support for development of portable noninvasive CAP detector based on Chinese population.