Experimental Study Of Ultrafast Pulse Wave Velocity Technology In Quantitative Evaluation Of Atherosclerosis And Preliminary Study Of The Correlation Between Arterial Elasticity And Nonalcoholic Fatty Liver Disease

Part one Experimental Study of Ultrafast Pulse Wave Velocity Technology in Quantitative Evaluation of Abdominal Aortic Elasticity inAtherosclerotic Rabbit ModelsObjective: The purpose of this study was to explore the value of ultrafast pulse wave velocity(UFPWV)technology in quantitative evaluation of arterial elasticity by detecting the abdominal aortic elasticity in atherosclerotic rabbit models fed up with high-fat diet(HFD).Methods: 45 male New Zealand white rabbits were randomly divided into two groups.A group of 35 rabbits were fed with HFD to establish animal models of AS,and another group of 10 rabbits were fed normal diet as normal control group.The elastic parameters were detected by UFPWV at the beginning and 24 th week,including the pulse wave velocity at the beginning of systole(PWVBs)and at the end of systole(PWVEs).Rabbits were sacrificed for pathological examination after UFPWV detection at 24 th week.HFD-fed rabbits with atherosclerotic plaques observed by pathological examination were divided into plaque group,and the ones without were divided into non-plaque group.Parameters of the HFD group and the normal control group were compared,and self contrast was made.Meanwhile the parameters in the non-plaque group,the plaque group and the normal control group were compared at 24 th week.The weight and weight increase of HFDgroup and the normal control group were also compared at 24 th week.The receiver operating characteristic curve(ROC curve)was plotted to evaluate the efficacy of UFPWV technology in the diagnosis of atherosclerosis(AS).Pearson correlation coefficient was used between the parameters and the weight.Result:1.The establishment of animal model: at 24 th week,none of the animals in normal control group were found with atherosclerotic plaque in abdominal aorta,while 17 rabbits in the HFD group were found with plaques.2.UFPWV detection of the abdominal aorta:(1)At 24 th week,both PWVBs and PWVEs of the HFD group were significantly higher than the normal control group,and also significantly higher than those in the same group before the feeding treatment(P < 0.05);(2)At 24 th week,both the parameters of the plaque group were higher than the normal control group and the non-plaque group(P < 0.05).Meanwhile,there was a statistically significant increase in the non-plaque group compared with the normal control group(P < 0.05);(3)The area under the ROC curve of the parameters in the diagnosis of AS were 0.873 and 0.892,respectively for PWVBs and PWVEs,which suggested that both the parameters had high efficiency in the diagnosis of AS.3.At 24 th week,the weight and weight increase of the HFD group were significantly higher than the normal control group,and both the elastic parameters PWVBs and PWVEs showed positive correlation with the weight(r=0.636;r=0.624).Conclusion:1.HFD could cause the decrease of arterial elasticity and successfullyestablish the atherosclerotic rabbit models,and there’s a certain correlation between body weight increase and decrease of arterial elasticity in the HFD condition.HFD manner of modern human beings should not be worth advocating.2.Arterial elasticity decreased parallel with the increase of arterial stiffness,and there’s a decrease of arterial elasticity in the early stage of AS before the morphological changes of the arterial wall,and UFPWV technology could successfully detect the early changes.3.UFPWV were effective in the diagnosis of AS,and had the potential to become a new quick detection technology with high application values instead of traditional methods.Part two Preliminary Study of the Correlation between Arterial ElasticParameters Detected by Ultrafast Pulse Wave Velocity Technology andNonalcoholic fatty liver diseaseObjective: The purpose of this study was to discuss the correlation between nonalcoholic fatty liver disease(NAFLD)and arterial elastic parameters detected by ultrafast pulse wave velocity(UFPWV)technology in NAFLD rabbit models.Methods: 45 male New Zealand white rabbits were randomly divided into two groups.A group of 35 rabbits were fed with HFD to establish animal models of NAFLD,and another group of 10 rabbits were fed normal diet as normal control group.At the beginning of the experiment and 24 th week,the UFPWV was performed to obtain the elastic parameters,including the pulse wave velocity at the beginning of systole(PWVBs)and at the end of systole(PWVEs),and conventional ultrasonic detection was also done for liver.At24 th week,rabbits were sacrificed for pathological examination.HFD-fed rabbits with fatty liver were classified as the experimental group,and all the rabbits were classified according to the pathological grades of fatty liver and stages of liver fibrosis.The parameters of the experimental group and the normal control group were compared,and meanwhile self contrast was made.Spearman correlation coefficient was used to analysis the correlation between the parameters and the grades,and also between the parameters and the stages.Result:1.The establishment of animal model: at 24 th week,no animals in the normal control group were found with NAFLD,while rabbits in the HFD group were found with fatty liver(F1: n=3;F2: n=14;F3:n=11)and liver fibrosis(S0:n=5;S1:n=7;S2:n=11;S3:n=3;S4:n=2).2.UFPWV detection of the abdominal aorta: at 24 th week,both the elastic parameters PWVBs and PWVEs of the experimental group were significantly higher than the normal control group,and also significantly higher than those in the same group before the feeding treatment(P < 0.05).3.At 24 th week,both the elastic parameters PWVBs and PWVEs positively correlated with the grade of fatty liver(r=0.717,P < 0.05;r=0.762,P < 0.05)and stage of fibrosis(r=0.779,P < 0.05;r=0.797,P < 0.05).Conclusion:1.There was a close relationship between NAFLD and AS in the HFD condition.The arterial elasticity of NAFLD rabbits was reduced.2.UFPWV technology could successfully detect the changes of arterial stiffness in different stages of NAFLD,and the arterial elasticity parametervalue increased with the raising of the fatty liver grade and fibrosis stage,which could not only be one of the cardiovascular risk assessment index but also reflected the severity of NAFLD to a certain extent.UFPWV showed profound practicability and popularization.