Ankle-brachial index and brachial-ankle pulse wave velocity are risk factors for ischemic stroke in patients with type 2 diabetes

The incidence of ischemic stroke in patients with diabetes is increasing. While brachial-ankle pulse wave velocity （BaPWV） and ankle-bra- chial index （ABI） are known to be associated with ischemic cardiovascular and cerebrovascular diseases, whether these measures predict the risk of ischemic cerebrovascular disease in diabetic patients remains unclear. 117 patients with type 2 diabetes were enrolled in this study. According to the results of head magnetic resonance imaging, the patients were divided into a diabetes-only group （n = 55） and a diabetes and ischemic stroke group （n = 62）. We then performed ABI and BaPWV examinations for all patients. Compared with the diabe- tes-only group, we found decreased ABI and increased BaPWV in the diabetes and ischemic stroke group. Multivariate logistic regression analyses revealed that BaPWV and ABI were risk factors for ischemic stroke in patients with type 2 diabetes. Our findings indicate that decreased ABI and increased BaPWV are objective indicators of increased risk of ischemic stroke in patients with type 2 diabetes.

Correlations between ultrasonic pulse wave velocities and rock properties of quartz-mica schist

Physico-mechanical properties are critically important parameters for rocks. This study aims to examine some of the rock properties of quartz-mica schist（QMS） rocks in a cost-effective manner by establishing correlations between non-destructive and destructive tests. Using simple regression analysis, good correlations were obtained between the pulse wave velocities and the properties of QMS rocks. The results were further improved by using multiple regression analysis as compared to those obtained by the simple linear regression analysis. The results were also compared to the ones obtained by other empirical equations available. The general equations encompassing all types of rocks did not give reliable results of rock properties and showed large relative errors, ranging from 23% to 1146%. It is suggested that empirical correlations must be investigated separately for different types of rocks. The general empirical equations should not be used for the design and planning purposes before they are verified at least on one rock sample from the project site, as they may contain large unacceptable errors.

Serum Calcium Level is Associated with Brachial-ankle Pulse Wave Velocity in Middle-aged and Elderly Chinese

Objective To study the relation between serum calcium level and elevated BaPWV in Chinese subjects. Methods The relation between serum calcium level and elevated BaPWV was studied in 9 615 subjects. The mean value of left and right BaPWV was analyzed. BaPWV was defined as high when it was31 752.5 cm/s （the upper quartile） either side. Results The BaPWV and its elevated percentage progressively increased across the quartiles of the serum calcium level （P〈0.05）. The prevalence of elevated BaPWV was significantly higher in subjects of the second, third and highest quartiles than in those of the lowest quartile （26.9%, 28.4%, and 33.2%vs 23.7%, P=0.0116, P=0.0004, and P〈0.0001）. Logistic regression analysis revealed that the risk of elevated BaPWV was 1.32- fold higher in subjects of the highest quartile than in those of the lowest quartile （OR=1.32, 95%CI：1.08-1.60）. Conclusion The elevated serum calcium level is related to an elevated BaPWV and a higher risk of arterial stiffness, independent of conventional risk factors, in middle-aged and elderly Chinese subjects.

THE EFFECTS OF BLOOD VISCOELASTICITY ON THE PULSE WAVE IN ARTERIES

Based on Womersley' s theory, the frequency equation satisfied by a complex wave velocity of a pulse wave in arteries war generalized to viscoelastic blood, a general formula of the complex wave velocity with regard to both linearly viscoelastic arteries and linearly viscolelastic blood was obtained, and the effects of the viscoelastic property of blood on the phase velocity and the wave attenuation of the pulse wave using the formula systematically was discussed. It is concluded that the influence of the blood elasticity on the wave propagation of a pulse wave in arteries is weaker than that of the arterial viscosity and may be neglected in larger arteries.

Relationship between the Plasma Fibulin-1 Levels,Pulse Wave Velocity,and Vascular Age in Asymptomatic Hyperuricemia

Fibulin-1(FBLN-1),an elastin-associated extracellular matrix protein,has been found in blood and may play a role in the pathophysiological processes leading to cardiovascular disease(CVD).We aimed to investigate the relationship between fibulin-1 levels and the risk of CVD by evaluating vascular age derived from the Framingham Heart Study and brachial-ankle Pulse Wave Velocity(baPWV)in patients with asymptomatic hyperuricemia(AHU).In total,66 patients with AHU and 66 gender-and age-matched healthy individuals were enrolled.The plasma fibulin-1 levels were measured by immunochemistry.Patients with AHU presented significantly higher vascular age[median(interquartile range):54(22)vs.48(14)years,P=0.01]and baPWV[mean±SD:1373±223 vs.1291±177 cm/s,P=0.02]than the healthy subjects;however,no significant difference was observed in the plasma fibulin-1 level between the patients with AHU and healthy subjects[median(interquartile range):4018(3838)vs.3099(3405)ng/mL,P=0.31].A correlation between fibulin-1 levels and baPWV was observed only in patients with AHU(r=0.29,P=0.02);and there was also a suggestively statistically significant correlation between fibulin-1 levels and vascular age(r=0.22,P=0.08).However,these associations were rendered insignificant after adjustments for potential confounders.In healthy subjects,no correlation was observed between fibulin-1 levels and CVD risk.This study reveals that plasma fibulin-1 levels may reflect the CVD risk in patients with AHU,but the relationship is not robust.

ANALYSE OF PULSE WAVE PROPAGATION IN ARTERIES

Based upon the blood vessel of being regarded as the elasticity tube, and that the tissue restricts the blood vessel wall, the rule of pulse wave propagation in blood vessel was studied. The viscosity of blood, the elastic modulus of blood vessel, the radius of tube that influenced the pulse wave propagation were analyzed. Comparing the result that considered the viscosity of blood with another result that did not consider the viscosity of blood, we finally discover that the viscosity of blood that influences the pulse wave propagation can not be neglected; and with the accretion of the elastic modulus the speed of propagation augments and the press value of blood stream heightens; when diameter of blood vessel reduces, the press of blood stream also heightens and the speed of pulse wave also augments. These results will contribute to making use of the information of pulse wave to analyse and auxiliarily diagnose some causes of human disease.

Relationship between brachial-ankle pulse wave velocity and metabolic syndrome components in a Chinese population

The purpose of this study was to assess the relationship between arterial stiffness, as measured by brachial-ankle pulse wave velocity （baPWV）, and the presence of the metabolic syndrome （MS） in a Chinese population. A total of 4,445 subjects were enrolled. The prevalence of MS in for the general population, males and females, respectively. our study population was 21.7%, 17.2% and 25.6% With adjustments for age, gender, cigarette smoking, heart rate, total cholesterol, low-density lipoprotein （LDL） cholesterol, and the use of anti-hypertensive drug, the stepwise regression analysis showed that baPWV had a significant relationship with components of MS, including systolic blood pressure （P 〈 0.001）, diastolic blood pressure （P 〈 0.001）, glucose （P 〈 0.001）, highdensity lipoprotein （HDL） cholesterol （P = 0.04）, and triglycerides （P 〈 0.001）, but no relationship with waist circumference （P = 0.25）. With an increase in the number of the MS components, baPWV increased significantly both in women and men. This study indicated that the MS is indeed a risk factor for arterial stiffness. Monitoring of baPWV in patients with MS may help in identifying persons at high risk for cardiovascular disease.

A More Effective Method of Extracting the Characteristic Value of Pulse Wave Signal Based on Wavelet Transform

Pulse wave contains human physiological and pathological information. Different people will exhibit different characteristics, and hence determining the characteristic points of the pulse wave of human physiological health makes sense. It is common that we extract the characteristic value of pulse wave signal with the method based on wavelet transform on a small scale, and then determine the locations of the characteristic points by modulus maxima and modulus minima. Before determining characteristic value by detecting modulus maxima and modulus minima, we need to determine every period of the pulse wave. This paper presents a new kind of adaptive threshold determination method which is more effective. It can accurately determine every period of the pulse wave, and then extract characteristic values by modulus maxima and modulus minima in every period of the pulse wave. The method presented in this paper promotes the research utilizing pulse wave on health life.

Association of Estimated Pulse Wave Velocity and the Dynamic Changes in Estimated Pulse Wave Velocity with All-Cause Mortality among Middle-Aged and Elderly Chinese

Objective We aimed to clarify the association between estimated pulse wave velocity(ePWV)and the changes in ePWV with all-cause mortality among middle-aged and elderly Chinese.Methods Data were obtained from the China Health and Retirement Longitudinal Study(CHARLS)from 2011-2018.The ePWV was calculated using an equation that included age and mean blood pressure(MBP).The ΔePWV was assessed as the difference in ePWV between the first two waves.Cox proportional hazard models were used to determine the association between ePWV and ΔePWV with all-cause mortality after adjustment for potential confounders.Results Of 13,116 participants during a median follow-up of 7.0 years,1,356 deaths occurred.An increased ePWV was independently associated with all-cause mortality.The hazard ratio[95% confidence interval(CI)]for participants from the 1^(st)-4^(th) quartile groups was 1.00,1.69(1.31-2.18),3.09(2.44-3.91),and 8.54(6.78-10.75),respectively.Each standard deviation(SD)increment of ePWV increased the risk of all-cause mortality by 132%.Furthermore,theΔePWV was significantly associated with a 1.28-fold(95%CI,1.18-1.38)risk of all-cause mortality per SD increment.Conclusion This cohort study provided novel evidence from a Chinese population that an increased ePWV or progression of the ePWV was independently associated with all-cause mortality,which highlighted the importance of mitigating ePWV progression in clinical practice.

Local Pulse Wave Velocity Estimation in the Carotids Using Dynamic MR Sequences

The current study presents a new protocol for local pulse wave velocity (PWV) measurement using dynamic MR sequences, which have a high temporal resolution (TR < 6 ms). MR images were obtained at two positions along the common carotid artery, separated by a distance of 5 cm. In each phase of a MR series, carotid region was automatically extracted and then its area distension waveform could be obtained. Sixteen volunteers with no symptoms of cardiovascular diseases were studied. For local PWV estimation, three delay estimation principles were tested and produced the following values: intersecting tangents method (M1): 4.72 ± 1.40 m/s, second derivative method (M2): 4.94 ± 1.68 m/s and cross-correlation method (M3): 5.03 ± 1.17 m/s. The cross-correlation method showed a relative high reliability as its least standard deviation.

THE INFLUENCE OF CARDIOVASCULAR DYNAMICCOUPLING ON THE BLOOD PULSE WAVE PROPAGATION IN HUMAN BODY

For the first lime, the pressure and flow pulse wave propagation phenomenon is studied in this paper on the basis of he cardiovascular dynamic coupling. E(t)-R model is adopted for left ventricle and T-Y tube model for systemic arteries. Furthermore, impulse response method and Fourier analysis method are employed After reasonable cardiovascular parameters and their value have been selected, the pressure and flow waveforms ape obtained at any poing along the systemic arteries. The results fit measured data well. In addition, the influences of cardiovascular parameters on pulse wave propagation are studied. The work is useful in practice.

3D interlocked all-textile structured triboelectric pressure sensor for accurately measuring epidermal pulse waves in amphibious environments

The performance degradation and even damage of the e-textiles caused by sweat,water,or submersion during all-weather health monitoring are the main reasons that e-textiles have not been commercialized and routinized so far.Herein,we developed an amphibious,high-performance,air-permeable,and comfortable all-textile triboelectric sensor for continuous and precise measurement of epidermal pulse waves during full-day activities.Based on the principle of preparing gas by acid-base neutralization reaction,a one-piece preparation process of amphibious conductive yarn(ACY)with densely porous structures is proposed.An innovative three-dimensional(3D)interlocking fabric knitted from ACYs(0.6 mm in diameter)and polytetrafluoroethylene yarns exhibit high sensitivity(0.433 V·kPa^(-1)),wide bandwidth(up to 10 Hz),and stability(>30,000 cycles).With these benefits,98.8%agreement was achieved between wrist pulse waves acquired by the sensor and a high-precision laser vibrometer.Furthermore,the polytetrafluoroethylene yarn with good compression resilience provides sufficient mechanical support for the contact separation of the ACYs.Meanwhile,the unique skeletonized design of the 3D interlocking structure can effectively relieve the water pressure on the sensor surface to obtain stable and accurate pulse waves(underwater depth of 5 cm).This achievement represents an important step in improving the practicality of e-textiles and early diagnosis of cardiovascular diseases.

Predictive Value of Carotid-femoral Pulse Wave Velocity for Major Adverse Cardiovascular Events and All-cause Mortality in Different Age Groups of a Chinese Community

Objective:To investigate the predictive value of carotid-femoral pulse wave velocity(cf-Pw)for assessing major adverse cardiovascular events(MACE)and all-cause mortality in different age groups of a Chinese community.Methods:This is an observational study which enrolled 1,325 individuals from a community in Beijing from September 2007 to October 2018.They were classified based on age into<65-year-old(n=572)and≥65-year-old(n=753)groups,and on cf-PWV into cf-PWV<12 m/s(n=501)and cf-PWV≥12 m/s(n=824)group.The incidence rates of MACE and all-cause mortality were recorded for both the groups during the follow-up period of 9.5 years.The predictive value of cf-PWV for MACE and all-cause mortality in the 2 age groups was estimated using the Cox proportional hazards regression models.Results:The baseline cf-PWV showed positive correlation with age(r=0.462,P<0.001).During the follow-up period,191 MACE and 84 all-cause mortality cases were recorded in the study population.The incidence rates of MACE(2=27.196,P<0.001)and all-cause mortality(x2=9.473,P=0.002)were significantly higher in subjects with cf-PWV≥12 m/s than in subjects with cf-PWV<12 m/s.Cox proportional hazards regression model analyses demonstrated that cf-PWV was an independent risk factor in the<65-year-old group for MACE(hazard ratio:1.310;95%confidence interval:1.007-1.560;P=0.038)and all-cause mortality(hazard ratio:1.412;95%confidence interval:1.133-1.936;P=0.005)after adjusting for several risk factors.However,both univariate and multivariate analyses demonstrated that cf-PWV was not an independent risk factor for MACE or all-cause mortality in the≥65-year-old group(P>0.05).Conclusion:cf-PWV,a measure of arterial stifness,emerged as an independent risk factor for MACE and all-cause mortality insubjectsbelow65yearsofage.

Increased brachial-ankle pulse wave velocity is associated with impaired endothelial function in patients with coronary artery disease

Background Pulse wave velocity and flow-mediated vasodilation （FMD） are widely used as noninvasive modalities for evaluating atherosclerosis. However, it is not known whether pulse wave velocity is related to FMD in patients with coronary artery disease （CAD）. Therefore, the present study was designed to investigate the alteration in brachial-ankle pulse wave velocity （baPWV） and endothelial function in CAD patients. Methods Thirty-three patients with CAD and thirty control subjects were recruited for this study, baPWV was measured non-invasively using a VP 1000 automated PWV/ABI analyzer （PWV/ABI, Colin Co. Ltd., Komaki, Japan）. Endothelial function as reflected by FMD in the brachial artery was assessed with a high-resolution ultrasound device. Results baPWV was increased in CAD patients compared with control subjects [（1756.1±253.1） cm/s vs （1495.3±202.3） cm/s, P〈0.01]. FMD was significantly reduced in CAD patients compared with control subjects [（5.2±2.1） % vs （11.1±4.4） %, P〈0.01]. baPWV correlated with FMD （r =-0.68, P〈0.001）. The endothelium-independent vasodilation induced by sublingual nitroglycerin in the brachial artery was similar in the CAD group compared with the control group.Conclusions CAD is associated with increased baPWV and endothelial dysfunction. Increased baPWV parallels diminished endothelial function. Our data therefore suggest that baPWV can be used as a noninvasive surrogate index in clinical evaluation of endothelial function.

Reference values of brachial-ankle pulse wave velocity for Northern Chinese

Background Brachial-ankle pulse wave velocity （baPWV） is a reliable method for measuring arterial elasticity, but the absence of reference value for baPWV has limited its wide use. We conducted an epidemical study in north China to investigate the reference value of baPWV for Chinese people and its influential factors. Methods A total of 974 identified healthy subjects were recruited in this study. The values of baPWV were evaluated noninvasively with an automatic device. Results For healthy population, the mean value of baPWV was higher for male （P 〈0.001）. Multiple regression analysis demonstrated that both age and systolic blood pressure were positively associated with baPWV for male and female （P 〈0.001）. BaPWV value was higher in male than in female in younger group （〈50 years） but not in older group （P〈-0.001）. The upper limits of baPWV were 1394/1264 cm/s, 1435/1361 cm/s, 1552/1433 cm/s, 1597/1609 cm/s and 1798/1915 cm/s for healthy male/female at 10 years interval （age range 20-70 years）. Conclusions Aging is the most important reason of arterial stiffness, but the effect of age on baPWV augmentation is greater for healthy female than their male counterpart. The reference values of baPWV by sex and age are very useful for clinical and preventive medicine.

Can we early diagnose metabolic syndrome using brachial-ankle pulse wave velocity in community population？

Background The prevalence of metabolic syndrome （MetS） increased recently and there was still not a screening index to predict MetS.The aim of this study was to estimate whether brachial-ankle pulse wave velocity （baPVVV）,a novel marker for systemic arterial stiffness,could predict MetS in Chinese community population.Methods A total of 2 191 participants were recruited and underwent medical examination including 1 455 men and 756 women from June 2011 to January 2012.MetS was diagnosed according to the criteria of the International Diabetes Federation （IDF）.Multiple Logistic regressions were conducted to explore the risk factors of MetS.Receiver operating characteristic （ROC） curve was performed to estimate the ideal diagnostic cutoff point of baPWV to predict MetS.Results The mean age was （45.35±8.27） years old.In multiple Logistic regression analysis,the gender,baPWV and smoking status were risk factors to MetS after adjusting age,gender,baPWV,walk time and sleeping time.The prevalence of MetS was 17.48% in 30-year age population in Shanghai.There were significant differences （Х^2=96.46,P 〈0.05） between male and female participants on MetS prevalence.According to the ROC analyses,the ideal cutoff point of baPWV was 1 358.50 cm/s （AUC=60.20%） to predict MetS among male group and 1 350.00 cm/s （AUC=70.90%） among female group.Conclusion BaPWV may be considered as a screening marker to predict MetS in community Chinese population and the diagnostic value of 1 350.00 cm/s was more significant for the female group.

Relationship between Neutrophil-to-Lymphocyte Ratio and Pulse Wave Velocity in Young Patients with Systemic Lupus Erythematosus

Background： The incidence of atherosclerosis-related myocardial infarction can be as much as 50-fold greater in young patients with systemic lupus e~,thematosus （SLE） than in age-matched controls. There are several explanations for this phenomenon, all of which result in a chronic state of low-grade inflammation. Recently, the neutrophil-to-lynlphocyte ratio （NLR） has been proposed as a useliil biomarker of inflammation. Pulse wave velocity （PWV） is a reliable indicator of vascular damage and atherosclerosis. There is a paucity of data concerning the relationship between NLR and atherosclerosis as measured by PWV in patients with SLE. This study aimed to verify whether there is a positive correlation between NLR and PWV and to explore factors that influence PWV in young SLE patients. Methods： A total of 90 female patients with SLE were enrolled in this cross-sectional investigation. Traditional and nontraditional cardiovascular risk factors were assessed on the same day that brachial-ankle PWV （baPWV） was examined. The patients were divided into three groups according to their mean baPWV values： patients whose mean baPWV value was lower than the first tertile were placed in Group 1 ： patients whose mean baPWV value was between the first tertile and the second tertile were placed in Group 2： and patients whose mean baPWV value was higher than the second tertile were placed in Group 3. SPSS 20.0 was used to perform all statistical analyses in this study. Both univariate linear regression and multivariate regression models were utilized to analyze the association between NLR and arterial stiffness. Results： Systolic blood pressure, diastolic blood presstire （DBP）. and triglycerides were all significantly different among Groups 1,2, and 3 （ 111.90 ± 12.85 mmHg vs. 114.60 ± 12.88 mmHg vs. 129.43 ±16.21 mmHg, P 〈 0.001 ： 68.77 ± 8.63 mmHg vs. 71.87 ± 9.77 mmHg vs. 82.57 ± 14.89 mmHg, P 〈 0.001 ; and 1.44 [0.91-2.47] mmol/L vs. 0.98 [0.78-1.26] mmol/L vs. 2.20 [0.94-3.66] mmol/L P = 0.030： respectively）, as were creatinine （57.50 [52.00-69.00] mmol/L vs. 55.50 [49.00-64.00] mmol/L vs. 64.00 [56.00-86.00] mmol/L P = 0.045） and blood urea nitrogen （4.27 [3.79-6.22] mmol/L vs. 4.16 [3.47-4.84] mmol/L vs. 5.88 [4.04-8.19] mmol/L, P = 0.011 ）. NLRs were significantly different among Groups 1, 2, and 3 （2.16 [1.56-3.42] vs. 3.12 [1.91-4.19] vs. 5.29 [2.63-7.25], P = 0.001）. N LR, together with DBP and the SLE disease activity index, independently predicts PWV. Conclusions： This study demonstrated that there was a positive correlation between NLR and PWV. Moreover, we found that disease activity and DBP were also positively correlated with PWV.

Altered heart rate variability and pulse-wave velocity after spinal cord injury

BACKGROUND Heart rate variability(HRV) and pulse-wave velocity(PWV),indicators of cardiac function,are altered in patients with spinal cord injury(SCI),suggesting that autonomic cardiac function and arterial stiffness may underlie the high risk of cardiovascular complications in these patients.No study has simultaneously investigated HRV and PWV in the same patients.AIM To evaluate cardiovascular complications in SCI patients by comparing HRV and PWV between patients with and without SCI.METHODS In this cross-sectional pilot study,patients with(n = 60) and without SCI(n = 60) were recruited from December 7,2019 to January 21,2020.Each participant received a five-minute assessment of HRV and the cardiovascular system using the Medicore HRV Analyzer SA-3000 P.Differences in HRV and PWV parameters between participants with and without SCI were statistically examined.RESULTS We observed a significant difference between participants with and without SCI with respect to the standard deviation of all normal-to-normal intervals,square root of the mean sum of squared successive risk ratio interval differences,physical stress index,total power,very-low frequency,low frequency,high frequency,and arterial elasticity.CONCLUSION Patients with SCI have weaker sympathetic and parasympathetic activity as well as lower arterial elasticity compared to those without,suggesting that SCI may increase cardiac function loading.

Lumped Parameter Outflow Models for 1-D Blood Flow Simulations:Effect on Pulse Waves and Parameter Estimation

Several lumped parameter,or zero-dimensional(0-D),models of the microcirculation are coupled in the time domain to the nonlinear,one-dimensional(1-D)equations of blood flow in large arteries.A linear analysis of the coupled system,together with in vivo observations,shows that:(i)an inflow resistance that matches the characteristic impedance of the terminal arteries is required to avoid non-physiological wave reflections;(ii)periodic mean pressures and flow distributions in large arteries depend on arterial and peripheral resistances,but not on the compliances and inertias of the system,which only affect instantaneous pressure and flow waveforms;(iii)peripheral inertias have a minor effect on pulse waveforms under normal conditions;and(iv)the time constant of the diastolic pressure decay is the same in any 1-D model artery,if viscous dissipation can be neglected in these arteries,and it depends on all the peripheral compliances and resistances of the system.Following this analysis,we propose an algorithm to accurately estimate peripheral resistances and compliances from in vivo data.This algorithm is verified against numerical data simulated using a 1-D model network of the 55 largest human arteries,in which the parameters of the peripheral windkessel outflow models are known a priori.Pressure and flow waveforms in the aorta and the first generation of bifurcations are reproduced with relative root-mean-square errors smaller than 3%.