Effects of Zhibitai capsules on blood lipids and arterial elasticity

Objective To evaluate the effects of Zhibitai(ZBT) on blood lipids and arterial elasticity in patients with high cardiovascular risk.Methods Eighty three subjects with high risk factors of cardiovascular diseases were enrolled into the study and randomized to two groups,i.e.,the ZBT group(n =44,treated with ZBT 0.48 g twice per day) and the atorvastatin(ATO) group(n =39,treated with ATO 10 mg per day).The levels of fasting serum lipids including total cholesterol(TC),triglyceride(TG),high and low density lipoprotein cholesterol(HDL-C and LDL-C) and pulse wave velocity(PWV) were investigated before and eight weeks after treatment.Results The serum levels of TG,TC,LDL-C,femoral-ankle PWV(FAPWV) and carotid-radial PWV(CRPWV) were markedly decreased after the therapy with ZBT or ATO for 8 weeks(P <0.05).There was no significant alteration in HDL-C and carotid-femoral PWV(CFPWV) levels in both ZBT and ATO groups(P >0.05) after eight-week's treatment.Conclusion ZBT could reduce the levels of FAPWV and CRPWV,thus improve the elasticity of medium-sized peripheral muscular arteries in addition to its lipids lowering effect.The efficacy of ZBT is similar to that of ATO.

Impaired Arterial Elasticity Identified by Pulse Waveform Analysis is a Non - invasive Measure for Early Detection of Endothelial Dysfunction

Objectives Endothelial dysfunction is the earliest marker for atherosclerosis and plays key role in the pathogenesis of cardiovascular diseases. The present study was performed to evaluate effect of aging on arterial elasticity by using pulse waveform analysis and investigate whether the changes in arterial elasticity can be used as a non - invasive measure for early detection of endothelial dysfunction. Methods Using modified Windkessel model of the circulation and pulse waveform analysis, C1 large ar- tery and C2 small artery elasticity indices of 204 normal healthy subjects ( age 15-80 years) were measured. Among them twenty - four male healthy subjects were divided into both the young ( age 20 - 30 years, n = 12) and elderly (age 60 -70 years, n = 12) groups. We delivered acethycholine (Ach) , an endothelium - dependent vasodilator, and sodium nitroprusside (SNP) , an endothelium - independent vasodilator, to dermal vessels of the forearm using iontophoresis, re- spectively, and measured basal and peak blood flow u- sing laser doppler fluximetry. Results Cl large ar- tery and C2 small artery elasticity indices were reduced with advancing age. C1 large artery and C2 small arter- y elasticity indices were negatively correlated with age (r= -0.628, p<0.001; r= -0.595, p<0.001). Basal blood flow was similar between the young andelderly groups (14. 58 ±3.4 vs 13. 52 ±3.41 PU, p = NS). Peak blood flow induced by Ach was significandy reduced in the elderly group compared with the young group (83.4 ±11.9 vs 93.75 ±10.87 PU, p <0.05). However, peak blood flow induced by SNP was similar in the two groups (119.17 ± 16.76 vs 128. 33 ±21. 29 PU, p = NS ) . Ach - induced peak blood flow correlated pos- itively with C1 large artery and C2 small artery elasticity indices(r = 0. 56, p < 0. 01; r =0.53, p < 0.01). Conclusions Advancing age leads to impaired artery elasticity and endothelial dysfunction. Reduced arterial elasticity is, in parallel, associated with diminished endothelium - dependent vasodilation. It is concluded that arterial elasticity assessment provides a non - inva- sive measure for the early evaluation of vascular endo- thelial function.

Impaired Arterial Elasticity Identified by Pulse Waveform Analysis as a Marker for Vascular Wall Damage in Humans With Aging and Hypertension

Objectives Cardiovascular risk factors lead to pathogenesis of atherosclerosis and its clinical events by impairing vascular wall. Endothelial dysfunction is the earliest marker for vascular wall injuries. Development of new method to detect early vascular wall damage has an important clinical implication for the prevention and treatment of cardiovascular diseases. Therefore, the present study was performed to evaluate effect of aging and hypertension, two independent risk factors for cardiovascular diseases, on arterial elasticity by using pulse waveform analysis and investigate whether the changes in arterial elasticity can be used as a risk marker for vascular structural and functional abnormalities. Methods Using modified Windkessel model of the circulation and pulse waveform analysis, C1 large artery and C2 small artery elasticity indices of 204 Chinese normal healthy subjects （ age 15-80 years） and 46 Chinese essential hypertensive patients （age 35-70 years） were measured. Age- and hypertension-related arterial elasticity changes were examined. Results C1 large artery and C2 small artery elasticity indices were reduced with advancing age in healthy subjects. C1 large artery and C2 small artery elasticity indices were negatively correlated with age （r=-0.628, P〈0.001; r=-0.595, P〈0.001）. C1 large artery and C2 small artery elasticity indices in patients with essential hypertension compared with the agematched healthy subjects were （9.31±3.85 ml/mm Hg × 10 versus 15.13±4.14 ml/mmHg × 10, P〈0.001） and （3.57 ± 1.62 ml/mm Hg x 100 versus 7.89±2.91 ml/ mmHg × 100 P 〈0.001）, respectively, and were significantly lower than the corresponding healthy subjects. There were negative association between C1 large artery and C2 small artery elasticity indices and systolic blood pressure （r=-0.37, P〈0.05; r=-0.39, P〈0.05） and pulse pressure （r=-0.39, P〈0.05; r=- 0.43,P〈0.05） in patients with essential hypertension. Conclusions Advancing age and essential hypertension lead to impaired artery elasticity and abnormalities in arterial elasticity are related with endothelial dysfunction. Reduced arterial elasticity may represent a marker for the risk of vascular wall damages. Arterial elasticity assessment offers a means of risk stratification for the clinical evaluation of vascular structural and functional injuries.

Effect of Chinese Herbal Medicine for Calming Gan(肝) and Suppressing Hyperactive Yang on Arterial Elasticity Function and Circadian Rhythm of Blood Pressure in Patients with Essential Hypertension

Objective：To observe the effect of Chinese herbal medicine for calming Gan（肝） and suppressing hyperactive yang（平肝潜阳,CGSHY） on arterial elasticity function and the circadian rhythm of blood pressure in patients with essential hypertension（EH）.Methods：Adopting a parallel,randomized design,sixty-four patients with EH of stagesⅠandⅡwere randomly divided into two groups according to a random number table,with 32 in each group.The patients in the treatment group were treated with CGSHY and those in the control group were treated with Enalapril.All patients were given 24-h ambulatory blood pressure monitoring（ABPM） before and after a 12-week treatment.Trough/peak（T/P） ratios of systolic and diastolic blood pressure（SBP DBP） of each group were calculated.The circadian rhythm of their blood pressure was observed at the same time. The changes in elasticity of the carotid artery in the patients,including stiffness parameter（β）,pressure-strain elastic modulus（Ep）,arterial compliance（AC）,augmentation index（Al）,and pulse wave velocity（PVWβ） were determined by the echo-tracking technique before and after a 12-week treatment.In the meantime,their levels of nitric oxide（NO） and endothelin-1（ET-1） were measured respectively.Results：After treatment,all parameters in the 24-h ABPM and the elasticity of the carotid artery（β,Ep,AC and PVWβ） were markedly improved,the level of NO was increased,and ET-1 was decreased in both groups as compared with values before treatment （P0.05 or P0.01）.Further,the improvements in the ratio of T/P of SBP DBP and in the level of NO and ET-1 in the treatment group were more significant than those in the control group（P0.05）.There were no significant differences in all parameters in the ABPM monitoring and the elasticity of the carotid artery,the recovery of blood pressure circadian rhythm,and the therapeutic effect of antihypertension in EH patients between the two groups （P0.05）.Conclusions：Chinese herbal medicine for CGSHY may lower the blood pressure smoothly and recover the circadian rhythm of blood pressure in EH patients.They may also improve the carotid elasticity of EH patients similar to that of Enalapril.The mechanism of action of Chinese herbs on EH might be related to the regulation of vascular endothelium function.

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.

Calculation and Analysis of Velocity and Viscous Drag in an Artery with a Periodic Pressure Gradient

Blood as a fluid that human and other living creatures are dependent on has been always considered by scientists and researchers.Any changes in blood pressure and its normal velocity can be a sign of a disease.Whatever significant in blood fluid＇s mechanics is Constitutive equations and finding some relations for analysis and description of drag,velocity and periodic blood pressure in vessels.In this paper,by considering available experimental quantities,for blood pressure and velocity in periodic time of a thigh artery of a living dog,at first it is written into Fourier series,then by solving Navier-Stokes equations,a relation for curve drawing of vessel blood pressure with rigid wall is obtained.Likewise in another part of this paper,vessel wall is taken in to consideration that vessel wall is elastic and its pressure and velocity are written into complex Fourier series.In this case,by solving Navier-Stokes equations,some relations for blood velocity,viscous drag on vessel wall and blood pressure are obtained.In this study by noting that vessel diameter is almost is large（3.7 mm）,and blood is considered as a Newtonian fluid.Finally,available experimental quantities of pressure with obtained curve of solving Navier-Stokes equations are compared.In blood analysis in rigid vessel,existence of 48% variance in pressure curve systole peak caused vessel blood flow analysis with elastic wall,results in new relations for blood flow description.The Resultant curve is obtained from new relations holding 10% variance in systole peak.

PERFORMANCE MODELING AND ANALYSIS OF BLOOD FLOW IN ELASTIC ARTERIES

Two different non_Newtonian models for blood flow are considered,first a simple power law model displaying shear thinning viscosity,and second a generalized Maxwell model displaying both shear thinning viscosity and oscillating flow viscous_elasticity.These models are used along with a Newtonian model to study sinusoidal flow of blood in rigid and elastic straight arteries in the presence of magnetic field.The elasticity of blood does not appear to influence its flow behavior under physiological conditions in the large arteries,purely viscous shear thinning model should be quite realistic for simulating blood flow under these conditions.On using the power law model with high shear rate for sinusoidal flow simulation in elastic arteries,the mean and amplitude of the flow rate were found to be lower for a power law fluid compared to Newtonian fluid for the same pressure gradient.The governing equations have been solved by Crank_Niclson scheme.The results are interpreted in the context of blood in the elastic arteries keeping the magnetic effects in view.For physiological flow simulation in the aorta,an increase in mean wall shear stress,but a reduction in peak wall shear stress were observed for power law model compared to a Newtonian fluid model for matched flow rate wave form.Blood flow in the presence of transverse magnetic field in an elastic artery is investigated and the influence of factors such as morphology and surface irregularity is evaluated.

Microalbuminuria associated with systolic blood pressure and arterial compliance in Chinese metabolic syndrome patients

Background There is significant evidence showing that microalbuminuria and arterial compliance are sensitive markers for early cardiovascular diseases. However, whether microalbuminuria is associated with reduced arterial compliance in Chinese metabolic syndrome （MS） patients remains unknown. Methods According to the definition of MS proposed by ATPⅢ in 2001, USA, subjects （n=362） were divided into three groups according to the number of risk factors： group 1 （control）, group 2 （medium, 〈 3 risk factors） and group 3 （MS, ≥ 3 risk factors）. Both large artery compliance （C1） and small artery compliance （C2） were measured with the CVProfilor DO-2020 Cardiovascular Profiling System, and microalbuminuria was evaluated with the ratio of albumin to urine creatinine. Results （1） As C1 and C2 levels elasticity decreased, albumin creatinine ratio （ACR） and the prevalence of microalbuminuria increased within those groups with MS risk factors. C1 and C2 were negatively correlated with the ranking of MS risk factors, ACR was positively correlated with the ranking of MS risk factors （all P〈0.05）. （2） Subjects were also categorized into a microalbuminuria group and a normal group, C1 and C2 in the microalbuminuria group were lower than in the normal group. （3） Multivariate regression analysis showed that increased systolic blood pressure （SBP） and reduced arterial compliance were the main risk factors for microalbuminuria in the MS group. Conclusions The risk of developing microalbuminuria was higher in the subjects with multiple metabolic abnormalities. Increased systolic blood pressure and reduced arterial compliance may be the main predictors for microalbuminuria in MS.

Effect of hormone therapy on carotid elasticity in postmenopausalwomen by Echo-tracking technique

Background Studies showed that arterial elasticity changes appear earlier than any structural changes, therefore, its accurate evaluation could be applied at early stage to prevent disease. Echo-tracking（E-tracking） technique can track the wall motion trajectory in real-time, calculate the change in vascular diameter automatically, and assessment of vascular stiffness and flexibility directly. This article aims to assess the change of elasticity of carotid artery after hormone therapy （HT） using Echo-tracking technology. Methods Echotracking was used to evaluate the carotid elastic moduli, such as the pressure-strain elastic modulus （Ep）, stiffness parameter （β）, arterial compliance （AC）, pulse wave conducting velocity （PWVβ） and augmentation index （AI） by Aloka α10 color Doppler ultrasound diagnosis system. Results Ep,β and PWVβ in HT group were significantly lower than those in the control group （P 〈 0.01）, while AC was obviously higher than the control group （P 〈 0.01）. E2 was negatively related to β, Ep and PWVβ （r = -0.607, r = -0.573, r = -0.574, P 〈 0.001）, while positively related to AC （r = 0.574, P 〈 0.001）; endothelial-dependent dilatation （EDD） was negatively related to β, Ep and PWVβ （r = -0.521, r = -0.411, r = -0.456, P 〈 0.001）, while positively related to AC （r = 0.443, P 〈 0.001）; But IMT was positively related to β, Ep and PWVβ（r = 0.553, r = 0.444, r = 0.529, P 〈 0.001）, while negatively related to AC （r = -0.400, P 〈 0.001）. Conclusions Arterial stiffness increases and compliance decreases in menopausal women. As EDD decreases arterial elasticity recedes, and HT can improve arterial elasticity. E-tracking technology can discover the early changes in arterial stiffness effectively and it is more sensitive in finding out the changes of stiffness in early atherosclerosis than IMT of carotid artery.

Hemodynamic effects of different fluid volumes for a fluid challenge in septic shock patients

Background:It is still unclear what the minimal infusion volume is to effectively predict fluid responsiveness.This study was designed to explore the minimal infusion volume to effectively predict fluid responsiveness in septic shock patients.Hemodynamic effects of fluid administration on arterial load were observed and added values of effective arterial elastance(Ea)in fluid resuscitation were assessed.Methods:Intensive care unit septic shock patients with indwelling pulmonary artery catheter(PAC)received five sequential intravenous boluses of 100 mL 4%gelatin.Cardiac output(CO)was measured with PAC before and after each bolus.Fluid responsiveness was defined as an increase in CO>10%after 500 mL fluid infusion.Results:Forty-seven patients were included and 35(74.5%)patients were fluid responders.CO increasing>5.2%after a 200 mL fluid challenge(FC)provided an improved detection of fluid responsiveness,with a specificity of 80.0%and a sensitivity of 91.7%.The area under the ROC curve(AUC)was 0.93(95%CI:0.84-1.00,P<0.001).Fluid administration induced a decrease in Ea from 2.23(1.46-2.78)mmHg/mL to 1.83(1.34-2.44)mmHg/mL(P=0.002),especially for fluid responders in whom arterial pressure did not increase.Notably,the baseline Ea was able to detect the fluid responsiveness with an AUC of 0.74(95%CI:0.59-0.86,P<0.001),whereas Ea failed to predict the pressure response to FC with an AUC of 0.50(95%CI:0.33-0.67,P=0.086).Conclusion:In septic shock patients,a minimal volume of 200 mL 4%gelatin could reliably detect fluid responders.Fluid administration reduced Ea even when CO increased.The loss of arterial load might be the reason for patients who increased their CO without pressure responsiveness.Moreover,a high level of Ea before FC was able to predict fluid responsiveness rather than to detect the pressure responsiveness.