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1
Xu, Minnan 1979. "Local measurement of the pulse wave velocity using Doppler ultrasound". Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/16868.
Testo completoAbstract (sommario):
Thesis (M.Eng. and S.B.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002.Includes bibliographical references (p. 77-79).
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cardiovascular disease is the leading cause of death in many developed countries. Arteries of people suffering from this disease become stiff and blocked by fatty deposits. In recent years, non-invasive imaging techniques have been playing an increasingly important role in detecting the development of cardiovascular disease. Several methods focus on the measurement of pulse wave velocity, the velocity at which the pressure wave propagates, because it is directly related to arterial stiffness. The objective of this project is to investigate the feasibility of measuring local pulse wave velocity from the blood flow waveforms acquired by Doppler ultrasound. The proposed method includes the following steps: first acquire flow waveforms by Doppler ultrasound at two locations within the same artery, next detect the delay or difference in arrival time of the flow wave at the two arterial locations, and then calculate the PWV by dividing the length of the arterial segment being imaged by the calculated time delay. Although at the conclusion of this study reliable pulse wave velocity detection is not achieved, the study sheds light on many important issues surrounding this potential application. The project explores how sources of variations such as radial positioning of the probe and noise level affect the accuracy of the delay estimate.
by Minnan Xu.
M.Eng.and S.B.
2
Ehrlich, Elizabeth R. "Sex Differences in Arterial Destiffening with Weight Loss". Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/43707.
Testo completoAbstract (sommario):
Given the current obesity epidemic in tandem with the aging US population, it is imperative to identify methods for reducing cardiovascular disease (CVD) risk that will be efficacious for both sexes. Arterial stiffness (AS) is an independent risk factor for a first cardiovascular event that increases with advancing age and obesity. Previous studies have found that modest weight loss (WL) of 5 to 10 percent successfully reduces AS and other risk factors for CVD. However, it remains unclear whether WL via caloric restriction reduces AS similarly among sexes. We tested the hypothesis that WL via caloric restriction would reduce AS more in men than women because men accumulate more abdominal visceral fat (VF) and lose more with WL compared with women of similar age and adiposity. To test our hypothesis AS was assessed from measurements of pulse wave velocity and ultrasonography of the carotid artery (Ã -SI). Total body and VF were measured using dual energy x-ray absorptiometry and computed tomography scans, respectively. Subjects underwent a 12-week WL intervention. No baseline differences in AS were observed between sexes. However, men were heavier and demonstrated higher levels of VF while women were fatter and had higher levels of abdominal subcutaneous fat. Contrary to our hypothesis both sexes experienced similar decreases in AS with WL despite greater reductions in VF in men. Our findings suggest that VF loss is not the primary mechanism mediating reductions in AS with WL. Future studies are needed to determine the mechanisms of arterial destiffening with WL.Master of Science
3
Wenngren, Wilhelm Sven Ingemar. "Local pulse wave velocity detection over an arterial segment using photoplethysmography". University of British Columbia, 2017. http://hdl.handle.net/2429/63867.
Testo completoAbstract (sommario):
The goal of this thesis is to determine the validity of using photoplethysmography (the detection of changes of blood volume using light) to measure pulse wave velocity as part of a continuous and non-disruptive blood pressure monitor. There has been a limited advancement over the years in technologies to monitor personal blood pressure, which have rendered at-home monitoring still relatively intrusive. The main method for at-home blood pressure monitoring is the use of an inflating cuff that obstructs the artery to detect pressure. This system suffers from inherit drawbacks, such as limitations on recording accuracy if insufficient time has passed between samples and the restrictive nature of the cuff which can induce pain on a user. An alternative device that can monitor continuously would thus benefit people who are sensitive or need 24-hour monitoring. Ideally this would be a system that can be worn without discomfort and does not interfere with the user in any way. The ideal device would also allow continuous blood pressure monitoring throughout the cardiac cycle, independent of the level of physical activity of the user. Furthermore, this type of device would allow athletes to measure blood pressure during activity.
To this end, a model is developed to describe blood pressure by measuring the arterial diameter on the radial artery and the pulse wave velocity (PWV) through it. Research suggests that these two metrics, along with the elasticity of an artery, can be used as a means to measure blood pressure non-invasively. This thesis focuses on the measurement of pulse wave velocity. The system design, including the hardware, is covered. The analysis techniques used to obtain raw signals, as well as the methods used to determine the PWV, will be discussed. The measurement location is described in detail. The results are shown to be comparable to values found in literature. However, due to lack of comparable measurement techniques, no direct comparisons between methods could be performed.Applied Science, Faculty of
Engineering, School of (Okanagan)
Graduate
4
GAO, LAN. "ARTERIAL STIFFNESS IN A RURAL POPULATION OF CHINA". Doctoral thesis, Università degli Studi di Milano-Bicocca, 2017. http://hdl.handle.net/10281/170799.
Testo completoAbstract (sommario):
Previous studies show that cf-PWV can predict cardiovascular events and mortality in both the general population and the patients with various diseases, such as hypertension, diabetes mellitus and end-stage renal disease. Current hypertension guidelines recommend the use of cf-PWV for the assessment of arterial stiffness and cardiovascular risk. It is of note that brachial-ankle PWV(ba-PWV) has been criticized due to the involvement of muscular arteries and the estimation of wave path from body height instead of real measurement. But ba-PWV is still extensively beingused in China for some reasons. For example, exposure of inguinal region could be ethically unacceptable for a majority of patients. Therefore, the primary aim of this study is 1) to measure the index of arterial stiffness, especially cf-PWV, in a rural population of China; 2) to assess the correlation between different measures of arterial stiffness.Previous studies show that cf-PWV can predict cardiovascular events and mortality in both the general population and the patients with various diseases, such as hypertension, diabetes mellitus and end-stage renal disease. Current hypertension guidelines recommend the use of cf-PWV for the assessment of arterial stiffness and cardiovascular risk. It is of note that brachial-ankle PWV(ba-PWV) has been criticized due to the involvement of muscular arteries and the estimation of wave path from body height instead of real measurement. But ba-PWV is still extensively beingused in China for some reasons. For example, exposure of inguinal region could be ethically unacceptable for a majority of patients. Therefore, the primary aim of this study is 1) to measure the index of arterial stiffness, especially cf-PWV, in a rural population of China; 2) to assess the correlation between different measures of arterial stiffness.
5
Matejková, Magdaléna. "Vyhodnocení vlastností tlakové vlny v lidském těle při různých excitacích". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2013. http://www.nusl.cz/ntk/nusl-220036.
Testo completoAbstract (sommario):
The thesis is concerned with the analysis of measuring pulse wave velocity in human body with the aid of whole-body multichannel bioimpedance which was developed at ISI AS CR, v.v.i.. The evaluation of pulse wave velocity can provide us with important information about the state of vessel compliance which is one of the basic parameters informing on their physiological state. The examination of the state of vascular system is a very important part of early diagnostics because its pathological states are the main contributor to the rise of cardiovascular diseases and disease mortality. The thesis is concerned with the theoretical analysis together with the available methods of valuation of the state of vascular system that use measuring of pulse wave velocity. The main part of the thesis deals with the analysis of the whole-body multichannel bioimpedance measurement. The proposed and programmed protocol that summarizes and visualizes all obtained information is a part of this thesis. This is currently used as an output of the experimental measurement by this method. Data file for statistical processing contains the values of the pulse wave velocity of 35 healthy volunteers and subsequently the properties of pulse wave are assessed at various excitations.
6
Perkiö, Mattias. "Assessment of Pulse Wave Velocity in the Aorta by using 4D Flow MRI". Thesis, Linköpings universitet, Institutionen för medicinsk teknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-110836.
Testo completoAbstract (sommario):
The purpose of this master thesis was to evaluate the estimation of pulse wave velocity (PWV) in the aorta using 4D flow MRI. PWV is the velocity of the pressure wave generated by the heart during systole and is a marker of arterial stiffness and a predictor of cardiovascular disease (CVD). PWV can in principle be estimated based on the time (travel-time) it takes for the pulse wave to travel a fixed distance (travel-distance), or based on the distance the pulse wave travels during a fixed time. In the commonly used time-to-travel-a-fixed-distance approach, planes are placed at two or more locations along the aorta. The travel-time is found by studying velocity waveforms at these pre-defined locations over time and thereby by estimating the time-difference for the pressure wave to reach each of these locations. In the distance-travelled-in-a-fixed-time approach, the pulse wave is located by studying at the velocity along the aorta at pre-defined instances in time. The travel-distance for the pulse wave between two instances in time is set as the difference in location of the pulse wave, where the location is identified as the location when the velocity has reached a predefined baseline. The specific aims of this thesis was to investigate the effect of using multiple locations as well as the effects of temporal and spatial resolution in the time-to-travel-a-fixed-distance approach, and to evaluate the possibility of using the distance-travelled-in-a-fixed-time approach. Additionally, the possibility of combining the two approaches was investigated. The study of using multiple locations revealed that more planes reduces the uncertainty of PWV estimation. Temporal resolution was found to have a major impact on PWV estimation, whereas spatial resolution had a more minor effect. A method for estimating PWV using 4D flow MRI using the distance-travelled-in-a-fixed-time approach was presented. Values obtained were compared favourably against previous findings and reference values, in the case of healthy young volunteers. The combination of the time-to-travel-a-fixed-distance and distance-travelled-in-a-fixed-time approaches appears feasible.
7
CESANA, FRANCESCA. "Variazioni di Pulse Wave Velocity durante quattro anni di follow up in una coorte di ipertesi essenziali". Doctoral thesis, Università degli Studi di Milano-Bicocca, 2012. http://hdl.handle.net/10281/28404.
Testo completoAbstract (sommario):
L’ipertensione arteriosa è una delle principali cause di malattia sia nei paesi sviluppati che in quelli in via di sviluppo, sia per l’ampia prevalenza della malattia che per gli effetti. E’ stato calcolato infatti che nel 2000 il 26.4% della popolazione mondiale era affetto da ipertensione e la percentuale di soggetti ipertesi è destinata a crescere fino a 29.2% nel 2025. Nella pratica clinica si ottengono due valori che sono ritenuti indicativi dell’omeostasi pressoria: la pressione di picco sistolica (PAS) e la pressione di fine diastole (PAD). Tradizionalmente si poneva particolare attenzione ai valori di pressione diastolica ritenendo che predicesse in maniera più indicativa della PAS la morbilità e mortalità cardiovascolari. Una ampia metanalisi condotta su 61 studi ed oltre un milione di individui senza patologia cardiovascolare conclamata, ha dimostrato come sia la PAS che la PAD siano entrambe predittori indipendenti della mortalità per IMA ed ictus.
I valori della pressione di picco sistolica e della pressione di fine diastole misurati con metodica non invasiva sono stati quindi assunti come indicativi del processo continuo che conduce dalla presenza di fattori di rischio (dislipidemia, ipertensione, diabete, fumo, obesità) allo scompenso cardiaco terminale attraverso la formazione della placca aterosclerotica e l’infarto del miocardio (4,5). Più di recente è stata dimostrata l’esistenza di un altro processo lesivo legato all’aumento della pressione arteriosa, ed indipendente da quello aterosclerotico, tale processo è caratteristico dell’invecchiamento e non coinvolge tanto le cellule quanto le componenti inanimate responsabili delle caratteristiche meccaniche della parete vasale, denominato arteriosclerosi.
Argomento di questa tesi sarà ampliare l’approccio al paziente iperteso non limitandoci alla misurazione dei valori sisto-diastolici di PA ma aggiungendo a questa valutazione tradizionale un dato sul funzionamento meccanico dei grandi vasi arteriosi stimando la rigidità aortica attraverso la misurazione della velocità della onda di polso (PWV), ed ipotizzando che variazioni del valore di questo parametro in misurazioni ripetute possano avere un’utilità clinica.
8
Zhao, Xuandong. "A study of Quantification of Aortic Compliance in Mice using Radial Acquisition Phase Contrast MRI". University of Cincinnati / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1273001921.
Testo completo
9
Sorvoja, H. (Hannu). "Noninvasive blood pressure pulse detection and blood pressure determination". Doctoral thesis, University of Oulu, 2006. http://urn.fi/urn:isbn:9514282728.
Testo completoAbstract (sommario):
Abstract
This thesis describes the development of pressure sensor arrays and a range of methods suitable for the long-term measurement of heart rate and blood pressure determination using a cuff and a pressure sensor array on the radial artery. This study also reviews the historical background of noninvasive blood pressure measurement methods, summarizes the accuracies achieved and explains the requirements for common national and international standards of accuracy.
Two prototype series of pressure transducer arrays based on electro-mechanical film (EMFi) were designed and tested. By offering high (∼TΩ) resistance, EMFi is an excellent material for low-current long-term measurement applications. About 50 transducer arrays were built using different configurations and electrode materials to sense low-frequency pressure pulsations on the radial artery in the wrist. In addition to uniform quality, essential requirements included an adequate linear response in the desired temperature range. Transducer sensitivity was tested as a function of temperature in the range of 25–45 °C at varying static and alternating pressures. The average sensitivity of the EMFi used in the transducers proved adequate (∼2.2 mV/mmHg and ∼7 mV/mmHg for normal and high sensitive films) for the intended purpose.
The thesis also evaluates blood pressure measurements by the electronic palpation method (EP) and compares the achieved accuracy to that of the oscillometric method (OSC) using average intra-arterial (IA) blood pressure as a reference. All of these three measurements were made simultaneously for each person. In one test group, measurements were conducted on healthy volunteers in sitting and supine position during increasing and decreasing cuff pressure. Another group, comprising elderly cardiac patients, was measured only in the supine position during cuff inflation. The results showed that the EP method was approximately as accurate as the OSC method with the healthy subjects and slightly more accurate with the cardiac patient group. The advantage of the EP method is that also the wave shape and velocity of arterial pressure pulses is available for further analysis, including the assessment of arterial stiffness.
10
Shah, Amy S. M. D. "Racial Differences in Arterial Stiffness Among Adolescents and Young Adults with Type 2 Diabetes". University of Cincinnati / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1298040943.
Testo completo
11
Hast, J. (Jukka). "Self-mixing interferometry and its applications in noninvasive pulse detection". Doctoral thesis, University of Oulu, 2003. http://urn.fi/urn:isbn:951426973X.
Testo completoAbstract (sommario):
Abstract
This thesis describes the laser Doppler technique based on a self-mixing effect in a diode laser to noninvasive cardiovascular pulse detection in a human wrist above the radial artery. The main applications of self-mixing interferometry described in this thesis in addition to pulse detection are arterial pulse shape and autonomic regulation measurements. The elastic properties of the arterial wall are evaluated and compared to pulse wave velocity variation at different pressure conditions inside the radial artery.
The main advantages of self-mixing interferometry compared to conventional interferometers are that the measurement set up is simple, because basically only one optical component, the laser diode, is needed. The use of fewer components decreases the price of the device, thus making it inexpensive to use. Moreover, an interferometer can be implemented in a small size and it is easy to control because only one optical axis has to be adjusted. In addition, an accuracy, which corresponds to half of the wavelength of the light source, can be achieved. These benefits make this technique interesting for application to the measurement of different parameters of the cardiovascular pulse.
In this thesis, measurement of three different parameters from cardiovascular pulsation in the wrist is studied. The first study considers arterial pulse shape measurement. It was found that an arterial pulse shape reconstructed from the Doppler signal correlates well to the pulse shape of a blood pressure pulse measured with a commercial photoplethysmograph. The second study considers measurement of autonomic regulation using the Doppler technique. It was found that the baroreflex part of autonomic regulation can be measured from the displacement of the arterial wall, which is affected by blood pressure variation inside the artery. In the third study, self-mixing interferometry is superimposed to evaluate the elastic properties of the arterial wall. It was found that the elastic modulus of the arterial wall increases as blood pressure increases. Correlations between measurements and theoretical values were found but deviation in measured values was large. It was noticed that the elastic modulus of the arterial wall and pulse wave velocity behave similarly as a function of blood pressure. When the arterial pressure increases, both the elastic modulus and pulse wave velocity reach higher values than in lower pressure.
12
Etyang, A. O. "Determining the causal role of malaria in elevating blood pressure and pulse wave velocity in Kenyan adolescents and adults". Thesis, London School of Hygiene and Tropical Medicine (University of London), 2018. http://researchonline.lshtm.ac.uk/4646135/.
Testo completoAbstract (sommario):
Introduction: High blood pressure is recognized as a leading risk factor for stroke and death in sub-Saharan Africa (sSA). While many studies have examined the role of established risk factors such as obesity and salt consumption, less is known about other factors, such as infection, that could be of particular importance in sSA. Ambulatory blood pressure measurement has emerged as the optimal method in recent years in Western settings, but there has been limited use to date in sSA. This work presents the results of a study investigating whether malaria, which is widespread in sSA could contribute to the development of high blood pressure using ambulatory measurements. Methods: Preliminary work involved determining the prevalence of hypertension in Kilifi, Kenya and examining the population-level effects of using ambulatory blood pressure monitoring (ABPM) for diagnosing hypertension. A literature review outlining the basis of the malaria-high blood pressure hypothesis and the Mendelian randomization method for testing the hypothesis was conducted. Sickle cell trait and alpha (+) thalassemia were chosen as instrumental variables to represent malaria exposure because they protect against malaria. Two studies were performed in Nairobi, Kenya among the same cohort to confirm that sickle-cell trait and alpha-thalassemia do not influence blood pressure in the absence of malaria and were therefore valid instrumental variables to test the malaria-high blood pressure hypothesis in Kilifi where there is malaria transmission. A Mendelian randomization study was then conducted in Kilifi, Kenya where 24-hour blood pressure and arterial 4 stiffness indices were compared in individuals with and without sickle cell trait and alpha thalassemia. Results: The prevalence of hypertension in Kilifi, a rural area, was found to be as high as in urban areas of Kenya despite the low frequency of classical risk factors such as obesity and excessive salt consumption. Use of ambulatory blood pressure monitoring for diagnosing hypertension was found to improve the accuracy of detection of high blood pressure. Neither Sickle-cell trait (SCT) nor alpha+ thalassemia influenced blood pressure or arterial stiffness indices among adolescents that had been lifelong residents of Nairobi, where there is no malaria transmission. Among individuals that had been lifelong residents of Kilifi, Kenya where there has been on-going malaria transmission, blood pressure was found to be lower among individuals with SCT, which protects against malaria episodes compared to those without SCT. The difference in BP by SCT status was larger in women than in men. There were no significant differences in arterial stiffness based on SCT status. Conclusion: This work suggests that malaria contributes to the burden of hypertension in sSA, and the control of malaria may lead to a reduction in blood pressure in this group. Future work should focus on confirming the findings using alternative study designs such as examining blood pressure in cohorts born before and after complete malaria elimination in parts of the world where this has been achieved. Subsequent work would involve delineating the pathophysiological mechanisms involved in malaria induced BP elevation with a view to generating new drugs to control hypertension.
13
Zanoli, Luca Maria. "Inflammation and arterial stiffness". Doctoral thesis, Università di Catania, 2012. http://hdl.handle.net/10761/1088.
Testo completoAbstract (sommario):
Arterial stiffness is one of the earliest detectable manifestations of adverse structural and functional changes within the vessel wall. It is well known that increased large artery stiffness independently predicts the cardiovascular risk in a variety of populations. The identification of populations at higher risk of increased arterial stiffness and the knowledge of the mechanisms involved in arterial stiffening may help to identificate pharmacological and other treatments to reduce the arterial stiffness and improve the outcome of the patients. Recently, new advances have been proposed about the active role of inflammation and endothelial dysfunction in arterial stiffening and early atherosclerosis. The aims of this thesis were to review the literature and to study, for the first time, the arterial stiffness in inflammatory bowel disease.
14
Murphy, J. C. "Comparison of a novel piezoelectric service for measuring arteral pulse wave velocity with a standard device in patients with hypertension". Thesis, Queen's University Belfast, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.517082.
Testo completo
15
Keeler, Jason Michael. "PREDICTORS OF ARTERIAL STIFFNESS IN LAW ENFORCEMENT OFFICERS". UKnowledge, 2018. https://uknowledge.uky.edu/khp_etds/48.
Testo completoAbstract (sommario):
The prevalence of cardiovascular disease (CVD) among law enforcement officers (LEOs) is slightly higher than the general population. Furthermore, the prevalence of CVD doubles among LEOs following retirement compared to the general population. The measure of arterial stiffness serves as an independent risk factor that has prognostic value for future incidence of CVD. However, there is limited research on lifestyle, occupational, and demographic factors that may be associated with increased arterial stiffness in LEOs. Therefore, the purpose of this investigation was to compare the level of arterial stiffness among LEOs versus the general population and to identify lifestyle, occupational, and demographic predictors of arterial stiffness in LEOs. Seventy male career LEOs between the ages of 24 to 54 years from Kentucky and southwest Ohio participated in this study. LEOs completed a variety of questionnaires related to health/occupational histories, occupational stress, and diet. LEOs’ body composition (bioelectrical impedance), central and brachial blood pressures, and physical activity (triaxial accelerometers) were assessed. The dependent variable of arterial stiffness was measured by carotid-femoral pulse wave velocity (cfPWV). A variety of statistical techniques including 1 sample t-tests, Pearson product moment correlations, and multiple linear regression were utilized in study analyses, with a level of significance set at p < 0.05. Compared to the general population cfPWV was significantly lower among LEO’s under 30 years of age (mean difference = -0.6 m·s-1), but significantly higher among LEOs 50-55 years of age (mean difference = 1.1 m·s-1). Utilizing stepwise multiple linear regression, age, relative body fat, and diastolic blood pressure explained the most variance in LEO’s cfPWV (adj. R2 = 0.56, p < 0.001). The primary findings of this investigation demonstrate that arterial stiffness may progress more rapidly in LEOs compared to the general population and that LEOs should focus on maintaining appropriate levels of relative body fat and blood pressure to regulate arterial stiffness and risk of CVD.
16
Hidegová, Simona. "Validace multikanálové bioimpedance cév za použití synchronizované cévní sonografie". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2021. http://www.nusl.cz/ntk/nusl-442505.
Testo completoAbstract (sommario):
The inclusion of a new device in clinical practice requires an adequate validation. The original publication which introduced multichannel bioimpedance monitor MBM was focused on discribing its technical parameters and demonstration measurements. Further evaluation desires comparision with other standard measuring device. This thesis describes pulse wave measurement by MBM and by other medical devices used for establishing cardiovascular risk. It proposes the validation experiment with synchronized vascular ultrasonography as a reference method. The process of the experimental measurement, aquired data and following data analysis are described in detail. The outputs of the experiment are statistically evaluated. The MBM’s performance and design of the experiment are discussed.
17
Simba, Kudakwashe. "The impact of vascular calcification among dialysis dependent South African CKD patients. A five year follow up study. Cardiovascular mortality and morbidity, ethnic variation and hemodynamic correlates". Master's thesis, Faculty of Health Sciences, 2019. http://hdl.handle.net/11427/31257.
Testo completoAbstract (sommario):
BACKGROUND
Vascular calcification is a major risk factor for cardiovascular morbidity and mortality in patients with end stage renal disease (ESRD). In Western countries, Blacks with ESRD appear to have lesser degrees of vascular calcification compared to non-Blacks. However, there is no published data on the association of ethnic differences in vascular calcification and survival in ESRD from Sub-Saharan Africa.
METHODS
This study assessed the 5-year change in vascular calcification and mortality in a previously published cohort of patients with ESRD. Vascular calcification was assessed by abdominal aortic calcification score (lateral abdominal radiograph) and vascular stiffness by pulse wave velocity.
RESULTS
Sixty-six of the original 74 participants, studied a baseline, were identified. The median age was 46.6 years (37.6-59.2) and 57.6% were women. Abdominal aortic calcification showed no progression among Blacks [baseline range 0-5, follow up range 0-8 (p=1.00)], but a nonsignificant trend to progression among non-Blacks [baseline range 0-19, follow up range 0-22 (p=0.066)]. Black participants did not display a survival advantage (p=0.870). Overall, sepsis was the most common cause of mortality (64% of those with an identifiable cause of death). Non-Blacks had higher parathyroidectomy rates than Blacks with 9/30 cases compared to 2/36 (p=0.036). After adjustment for parathyroidectomy at follow up, the odds ratio of having abdominal vascular calcification score of ≥1 amongst non-Blacks was 8.6-fold greater compared to Blacks (p= 0.03). Central aortic systolic pressures (CASP) and pulse wave velocities (PWV) were higher in the study population than age matched normative values. At follow up, a positive correlation (r=0.3) was observed between PWV and abdominal aortic calcification (p=0.04). Elevated baseline coronary artery calcification score and FGF-23 level at baseline were not associated with a difference in mortality.
CONCLUSION
There was no significant progression in vascular calcification among Blacks. After adjusting for increased parathyroidectomy rates, there was a greater progression of vascular calcification amongst non-Blacks compared to Blacks highlighting possible ethnic differences in calcium phosphate metabolism in patients with ESRD. The lack of vascular calcification progression in Blacks was not however associated with improved survival, but the sample size was small.
18
Alvim, Rafael de Oliveira. "Impacto de marcadores genéticos no fenótipo de rigidez arterial em uma população geral". Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/5/5166/tde-02102012-083411/.
Testo completoAbstract (sommario):
Introdução: A rigidez arterial é um fenômeno complexo caracterizado pela diminuição da complacência vascular frente aos estímulos fisiológicos e patológicos. Semelhantemente a outros fenótipos cardiovasculares, a etiologia da rigidez arterial é modulada por fatores ambientais e genéticos. Levando em consideração a moderada herdabilidade e a característica poligênica do presente fenótipo, torna-se interessante a investigação de marcadores genéticos referentes aos diferentes sistemas envolvidos no remodelamento vascular. Objetivo: Avaliar o impacto dos polimorfismos C242T da subunidade p22phox da NADPH oxidase, G1036C da TXNIP, C609T/T471C da APOE, G1355A da elastina, I/D da ECA e A855G da MMP-9 no fenótipo de rigidez arterial em uma população geral. Métodos: Participaram do estudo 1.663 indivíduos da população geral da cidade de Vitória-ES. O DNA foi extraído a partir de uma amostra de sangue venoso. Posteriormente foram realizadas as genotipagens para as variantes genéticas supracitadas. A rigidez arterial foi avaliada por meio do método da velocidade de onda de pulso (VOP). Resultados: Em relação à VOP, os polimorfismos C242T da subunidade p22phox da NADPH oxidase e G1036C da TXNIP foram signifcativamente associados. Os indivíduos portadores do genótipo TT do polimorfismo C242T da subunidade p22phox (CC+TC=9,8 m/s versus TT=10,1 m/s, p=0,02) e do alelo G do polimorfismo G1036C da TXNIP (CC=9,8 m/s versus CG+GG=10,0 m/s, p=0,03) apresentaram maiores valores da VOP. Entretanto os polimorfismos C609T/T471C da APOE (2=10,0 m/s, 3=9,8 m/s, 4=9,8 m/s, p=0,60), G1355A da elastina (AA=9,8 m/s, GA=9,9 m/s, GG=9,8 m/s, p=0,92), I/D da ECA (DD=9,8 m/s, DI=9,8 m/s, II=9,9 m/s, p=0,53) e A855G da MMP-9 (AA=9,8 m/s, GA=9,8 m/s, GG= 9,8 m/s, p=0,60) não demonstraram tal associação. Somente o genótipo TT do polimorfismo C242T da subunidade p22phox (OR=1,93, p=0,002) apresentou um risco significativamente aumentado para o fenótipo de rigidez arterial. Já os polimorfismos G1036C da TXNIP (OR=1,19, p=0,19), C609T/T471C da APOE (OR=1,14, p=0,33), G1355A da elastina (OR=0,81, p=0,28), I/D da ECA (OR=0,91, p=0,48) e A855G da MMP-9 (OR=1,01, p=0,95) não apresentaram risco. Conclusão: Os polimorfismos C242T da subunidade p22phox da NADPH oxidase e G1036C da TXNIP podem contribuir como moduladores genéticos no enrijecimento vascularIntroduction: Arterial stiffness is a complex phenomenon characterized by decreased vascular compliance during physiological and pathological stimuli. Similar to other cardiovascular phenotypes, arterial stiffness etiology is modulated by environmental and genetic factors. Considering the moderate heritability and its polygenic phenotype, genetic markers investigations related to different systems involved in vascular remodeling are interesting. Objectives: To assess the impact of the p22phox C242T, TXNIP G1036C, APOE C609T/T471C, elastin G1355A, ACE I/D and MMP-9 A855G polymorphisms on arterial stiffness phenotype in a general population. Methods: This study included 1,663 individuals of the general population from Vitória-ES. DNA was extracted from a venous blood sample and genotyping assays were performed for the genetic variants described above. Arterial stiffness was evaluated by pulse wave velocity (PWV). Results: Regarding PWV, p22phox C242T and TXNIP G1036C polymorphisms were significantly associated. Individuals carrying TT genotype of the p22phox C242T (CC + CT vs TT = 9.8 m/s = 10.1 m/s, p = 0.02) and individuals carrying G allele of the TXNIP G1036C polymorphisms (CG + CC = 9.8 m/s vs GG = 10.0 m/s, p = 0.03) had higher PWV values. However, APOE C609T/T471C (2=10.0 m/s, 3=9.8 m/s, 4=9.8 m/s, p=0.60), elastin G1355A (AA=9.8 m/s, GA=9.9 m/s, GG=9.8 m/s, p=0.92), ACE I/D (DD=9.8 m/s, DI=9.8 m/s, II=9.9 m/s, p=0.53) and MMP-9 A855G (AA=9.8 m/s, GA=9.8 m/s, GG= 9.8 m/s, p=0.60) polymorphisms did not present association. Only the TT genotype of the p22phox C242T polymorphism (OR = 1.93, p = 0.002) presented an increased risk for the arterial stiffness phenotype. Already TXNIP G1036C (OR=1.19, p=0.19), APOE C609T/T471C (OR=1.14, p=0.33), elastin G1355A (OR=0.81, p=0.28), ACE I/D (OR=0.91, p=0.48) and MMP-9 A855G (OR=1.01, p=0.95) polymorphisms did not present risk. Conclusion: The p22phox C242T and the TXNIP G1036C polymorphisms may contribute to genetic modulators in vascular stiffening
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Öhman, Fredrik. "Går det att mäta blodtryck med fotopletysmografi och bioakustisk sensor i kombination?" Thesis, Linköping University, Department of Biomedical Engineering, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-2819.
Testo completoAbstract (sommario):
The aim of the work was to investigate the possibility to combine information from PPG and bio-acoustic technology to extract information that is related to the blood pressure. The measurements have been carried out with several different configurations. First the relation between arterial sounds and the PPG-signal was studied. After those measurements with both PPG and the bio- acoustic technique was concluded on people in different positions and after riding a bike. The goal was to vary the blood pressure. The conclusion that can be drawn in this report is that the bio-acoustic and the PPG-signal in peripheral arteries have the same source. That implies that arterial sounds are a product of turbulence when the pulse wave passes by. Further it can be assumed that it is the first heart sound that is represented in the arterial sounds. The time before and after the arterial sound in one heart cycle vary whit the blood pressure. There relationship seems also to vary with the bloodpressure but it vary differently under different conditions.
20
Dahlén, Elsa, Niclas Bjarnegård, Toste Länne, Fredrik H. Nyström e Carl Johan Östgren. "Sagittal abdominal diameter is a more independent measure compared with waist circumference to predict arterial stiffness in subjects with type 2 diabetes - a prospective observational cohort study". Linköpings universitet, Allmänmedicin, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-93864.
Testo completoAbstract (sommario):
Background Anthropometric measurements are useful in clinical practice since they are non-invasive and cheap. Previous studies suggest that sagittal abdominal diameter (SAD) may be a better measure of visceral fat depots. The aim of this study was to prospectively explore and compare how laboratory and anthropometric risk markers predicted subclinical organ damage in 255 patients, with type 2 diabetes, after four years. Methods Baseline investigations were performed in 2006 and were repeated at follow-up in 2010. Carotid intima-media thickness (IMT) was evaluated by ultrasonography and aortic pulse wave velocity (PWV) was measured with applanation tonometry over the carotid and femoral arteries at baseline and at follow-up in a cohort of subjects with type 2 diabetes aged 55–65 years old. Results There were significant correlations between apolipoprotein B (apoB) (r = 0.144, p = 0.03), C - reactive protein (CRP) (r = 0.172, p = 0.009) at baseline and IMT measured at follow-up. After adjustment for sex, age, treatment with statins and Hba1c, the associations remained statistically significant. HbA1c, total cholesterol or LDL-cholesterol did not correlate to IMT at follow-up. Baseline body mass index (BMI) (r = 0.130, p = 0.049), waist circumference (WC) (r = 0.147, p = 0.027) and sagittal Abdominal Diameter (SAD) (r = 0.184, p = 0.007) correlated to PWV at follow-up. Challenged with sex, SBP and HbA1c, the association between SAD, not WC nor BMI, and PWV remained statistically significant (p = 0.036). In a stepwise linear regression, entering both SAD and WC, the association between SAD and PWV was stronger than the association between WC and PWV. Conclusions We conclude that apoB and CRP, but not LDL-cholesterol predicted subclinical atherosclerosis. Furthermore, SAD was more independent in predicting arterial stiffness over time, compared with WC, in middle-aged men and women with type 2 diabetes.Funding Agencies|Medical Research Council of Southeast Sweden||Center for Medical Image Science and Visualization (CMIV)||Linkoping University||Futurum||King Gustaf V and Queen Victoria Freemason Foundation||GE Healthcare||Swedish Heart-Lung Foundation||Swedish Research Council Grant|12661|
21
Madueme, Peace C. "Predictors of Exaggerated Exerise-Induced Systolic Blood Pressures in Young Patients After Coarctation Repair". University of Cincinnati / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1337887220.
Testo completo
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Teren, Andrej, Frank Beutner, Kerstin Wirkner, Markus Löffler e Markus Scholz. "Relationship between determinants of arterial stiffness assessed by diastolic and suprasystolic pulse oscillometry". Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-205538.
Testo completoAbstract (sommario):
Pulse wave velocity (PWV) and augmentation index (AI) are independent predictors of cardiovascular health. However, the comparability of multiple oscillometric modalities currently available
for their assessment was not studied in detail. In the present study, we
aimed to evaluate the relationship between indices of arterial stiffness
assessed by diastolic and suprasystolic oscillometry. In total, 56 volunteers from the general population (23 males; median age 70 years [interquartile range: 65–72 years]) were recruited into observational feasibility study to evaluate the carotid-femoral/aortic PWV (cf/aoPWV), brachial-ankle PWV (baPWV), and AI assessed by 2 devices: Vicorder (VI) applying diastolic, right-sided oscillometry for the determination of all 3 indices, and Vascular explorer (VE) implementing single-point, suprasystolic brachial oscillometry (SSBO) pulse wave analysis for the assessment of cfPWV and AI. Within- and between-device correlations of measured parameters were analyzed. Furthermore, agreement of repeated measurements, intra- and inter-observer concordances were determined and compared for both devices. In VI, both baPWVand cfPWVinter-correlatedwell and showed good level of agreement with bilateral baPWVmeasured byVE (baPWV[VI]– baPWV[VE]R: overall concordance correlation coefficient
[OCCC]¼0.484, mean difference¼1.94 m/s; cfPWV[VI]–baPWV[- VE]R: OCCC¼0.493, mean difference¼1.0m/s). In contrast, SSBO derived aortic PWA (cf/aoPWA[VE]) displayed only weak correlation with cfPWV(VI) (r¼0.196; P¼0.04) and ipsilateral baPWV (cf/ aoPWV[VE]R–baPWV[VE]R: r¼0.166; P¼0.08). cf/aoPWA(VE) correlated strongly with AI(VE) (right-sided: r¼0.725, P<0.001). AI exhibited marginal between-device agreement (right-sided: OCCC¼ 0.298, mean difference: 6.12%). All considered parameters showed good-to-excellent repeatability giving OCCC > 0.9 for 2-point-PWV modes and right-sided AI(VE). Intra- and inter-observer concordances were similarly high except for AI yielding a trend toward better reproducibility in VE (interobserver–OCCC[VI] vs [VE]¼0.774 vs 0.844; intraobserver OCCC[VI] vs [VE]¼0.613 vs 0.769). Both diastolic oscillometry-derived PWV modes, and AI measured either with VI or VE, are comparable and reliable alternatives for the assessment of arterial stiffness. Aortic PWV assessed by SSBO in VE is not related to the corresponding indices determined by traditional diastolic oscillometry.
23
Stucke, Dea. "Association of dietary advanced glycation end products (AGEs) with inflammation and arterial stiffness in youth with type I diabetes". University of Cincinnati / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1592135011714719.
Testo completo
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Moore, Stephanie M. "EFFECT OF BODY MASS INDEX ON POST-EXERCISE HEMODYNAMIC RESPONSES". UKnowledge, 2014. http://uknowledge.uky.edu/khp_etds/14.
Testo completoAbstract (sommario):
To assess the relationships of body mass index (BMI) on arterial stiffness at rest and post-maximal treadmill graded exercise testing (GXT).
Forty-four apparently healthy, young adult males (22.1 ± 0.48 years) were recruited and divided into either a healthy weight (H, ≤24.9 kg/m2), overweight (OV, 24.9-29.9 kg/m2) or obese (OB, ≥29.9 kg/m2) group based on BMI. All subjects underwent arterial stiffness (carotid-femoral pulse wave velocity, cfPWV), blood pressure (BP), pulse pressure (PP), mean arterial pressure (MAP) and body composition (bioelectrical impedance analysis, BIA) measurements at rest. Following the GXT, measures of arterial stiffness (cfPWV) and BP were acquired.
Resting measures of cfPWV, BMI, systolic BP, diastolic BP, MAP, and PP were significantly (p <0.05) greater in OV and OB compared with H. Compared with OV, OB had a greater BMI. Relative peak oxygen consumption (VP2peak) was greater in H compared with OV and OB (p<0.05). systolic BP was positively associated, whereas VO2peak was inversely related to cfPWV (p<0.05). No significant inter-group interactions were observed with cfPWV after the GXT. However, interactions were observed for SBP, DBP and PP (p<0.05).
In young men with varying BMI, SBP and VO2peak were associated with resting cfPWV. However, similar cardiovascular responses were observed between groups after a maximal GXT.
25
Majeed, Beenish. "Immune Modulation of Vascular Stiffening". Diss., The University of Arizona, 2014. http://hdl.handle.net/10150/325419.
Testo completoAbstract (sommario):
Vascular stiffening is defined as the reduced ability of the blood vessels to expand in response to an increase in blood pressure. Vascular stiffening is often not appreciated as a disease in and of itself but is important to recognize because it is considered a predictor of many cardiovascular disease states. Mechanisms of vascular stiffening remain largely unknown; however the immune system has been found to play major roles in cardiovascular disease and arterial remodeling. This dissertation therefore seeks to illustrate the role of the adaptive immune system in vascular stiffening. This has been done by modeling vascular stiffness in transgenic mice lacking an adaptive immune system as well as immunosuppression in normal mice using a novel method to stimulate regulatory T cells with a cytokine immune complex. We have found that inhibition of the immune system by the use of a genetic knockout (RAG 1 ⁻/⁻ mice) or suppression of an existing immune system with an IL-2/anti-IL-2 complex reduces the development of angiotensin II-induced vascular stiffening. This dissertation supports the role of the adaptive immune system, and particularly CD4⁺T cells, in the development of vascular stiffening as well as the protective roles of Tregs in the disease. It also highlights the use of the IL-2/anti-IL-2 complex as a new potential therapy for vascular stiffness. Therapeutics that suppress adaptive immune function may be beneficial in the treatment of vascular stiffening.
26
Benešová, Lenka. "Vyhodnocení variability rychlosti pulzové vlny". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2019. http://www.nusl.cz/ntk/nusl-400981.
Testo completoAbstract (sommario):
This diploma thesis deals with the variability of pulse wave velocity. It studies the variability of cardiovascular signals. It presents the research of measurement of pulse wave velocity and its analysis in physiology and pathological physiology. Applies spectral analysis in Matlab to a data set. It evaluates and reviews the results of this analysis
27
BARROS, Zoraya de Medeiros. "Fatores de risco para rigidez aórtica e sua progressão em pessoas vivendo com HIV/AIDS no estado de Pernambuco". Universidade Federal de Pernambuco, 2015. https://repositorio.ufpe.br/handle/123456789/16507.
Testo completoAbstract (sommario):
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Tese de Zoraya versão definitiva 131015 aceita.pdf: 2706371 bytes, checksum: 83da3cf5bbbffb2d66214831901498f3 (MD5)Made available in DSpace on 2016-04-12T15:21:22Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Tese de Zoraya versão definitiva 131015 aceita.pdf: 2706371 bytes, checksum: 83da3cf5bbbffb2d66214831901498f3 (MD5) Previous issue date: 2015-02-27
Esta tese teve como objetivo estudar um marcador de aterosclerose subclínica, a rigidez aórtica, medida através da velocidade de onda de pulso aórtica, diante da importância de se identificar os pacientes com risco maior de desenvolver doenças cardiovasculares (DCV), hoje, uma das principais causas de morbidade e mortalidade, não relacionada à síndrome da imunodeficiência adquirida (AIDS) em pessoas vivendo com o vírus da imunodeficiência humana (PVHIV). Entre setembro de 2011 e janeiro de 2013, a população do estudo composta por homens e mulheres vivendo com o vírus da imunodeficiência humana (HIV), participantes da coorte HIV/AIDS-PE, no nordeste do Brasil, iniciada em 2007, foi submetida a dois desenhos de estudos visando identificar os fatores de risco cardiovasculares tradicionais e emergentes associados com a rigidez aórtica e sua progressão.Visando identificar fatores de riscos cardiovasculares emergentes, incluindo a perda de massa óssea, realizamos um estudo transversal em mulheres vivendo com HIV que haviam realizado densitometria mineral óssea, no período entre Outubro de 2010 a Novembro de 2011. A densidade mineral óssea (DMO), foi medida pela absorciometria de energia dupla de raio-x de (DXA) nas regiões da coluna lombar, colo de fêmur e fêmur total e a rigidez aórtica, foi medida pela velocidade de onda de pulso aórtica (VOPa). O resultado principal deste estudo foi a correlação negativa significante entre a DMO do colo de fêmur e do fêmur total com a VOPa mesmo ajustada para idade, síndrome metabólica e pressão arterial média. Sugerindo que mulheres vivendo com HIV com perda de massa óssea deverão ser avaliadas para doença cardiovascular aterosclerótica. Para investigar a progressão da rigidez aórtica, foram acompanhados por uma média de 2,9 anos, homens e mulheres vivendo com HIV que haviam realizado a primeira avaliação da rigidez aórtica entre Abril e Novembro de 2009. O achado mais importante deste estudo foi a verificação de uma acelerada progressão da rigidez aórtica associada a fatores de risco tradicionais, idade, sexo masculino e hipertensão arterial e uma correlação negativa com a duração da infecção em uma população sob bom controle virológico. Os dados favorecem intensificar medidas para melhor controle da hipertensão arterial e da imunodeficiência.
This thesis aimed to study a marker of Subclinical Atherosclerosis, aortic stiffness measured by aortic pulse wave velocity, given the importance of identifying the patient with higher risk of developing cardiovascular diseases, today, one of the leading causes of morbidity and mortality, not related to AIDS. Between September 2011 and January 2013, the study population comprised of men and women living with human immunodeficiency virus (HIV), HIV/AIDS cohort participants-PE, in northeastern Brazil, initiated in 2007, have undergone two designs of studies aimed at identifying the factors of traditional and emerging cardiovascular risk associated with aortic stiffness and its progression. Aiming to identify emerging cardiovascular risk factors, including the loss of bone mass, we performed a cross-sectional study in women living with HIV who had performed bone mineral densitometry in the period between October 2010 to November 2011. Bone mineral density was measured by dual-energy x-ray absorptiometry (DXA) in regions of the lumbar spine, neck femur and total femur and aortic stiffness was measured by aortic pulse wave velocity (aPWV). The main result of this study was the significant negative correlation between the BMD of the femoral neck and total femur aPWV even adjusted for age, metabolic syndrome and mean arterial pressure. Suggesting that women living with HIV with low of bone mass should be assessed for atherosclerotic cardiovascular disease. To investigate the progression of aortic stiffness, were accompanied by an average of 2.9 years, men and women living with HIV who had carried out the initial evaluation of aortic stiffness between April and November 2009 .The most important finding of this study was the verification of an accelerated progression of aortic stiffness associated with traditional risk factors, age, male and hypertension and a negative correlation with duration of infection in a population under good viral control. The data favor the aggressive measures of intensify and immunodeficiency hypertension.
28
Tichoň, Dušan. "Analýza šíření tlakové vlny v aortě". Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-418205.
Testo completoAbstract (sommario):
The aim of this diploma thesis is to assess the applicability of pulse wave propagation monitoring in the cardiovascular system in the field of prediction and early diagnosis of abdominal aortic aneurysm (AAA). The very first part is focused on description of heart and blood vessels with its pathological changes in presence of aneurysm. For this reason, current methods of monitoring and surgical treating of AAA were mentioned. Due to their difficult clinical use widely in the population, new methods based on pulse wave monitoring were presented. Using an analytical approach we estimated the difference in the arrival of the pulse wave at measurable locations between healthy and pathological aorta in the order of miliseconds. By experimental monitoring using photoplethysmographic sensors, we observed significant changes of pulse wave velocity with respect to the mechanical properties of the artery wall (mainly associated with age), which we tried to implement by hyperelastic material models used in computational simulations of pulse wave proagation on simplified geometries by fluid structure interaction method. These analyzes should verify applicability of FSI simulations in further development of diagnostic methods of AAA.
29
Rastelli, Stefania. "Struttura e funzione arteriosa nelle malattie infiammatorie croniche intestinali". Doctoral thesis, Università di Catania, 2015. http://hdl.handle.net/10761/4023.
Testo completoAbstract (sommario):
Le malattie infiammatorie croniche intestinali (IBD) sono associate ad un aumentato rischio cardiovascolare non completamente spiegabile con la prevalenza dei fattori di rischio cardiovascolare tradizionali. L'infiammazione e l'aumento della rigidità arteriosa ad essa correlata potrebbero avere un ruolo importante nella valutazione del rischio cardiovascolare di questi soggetti. In questa tesi ho studiato la correlazione tra infiammazione e rigidità arteriosa nelle IBD. Per la prima volta ho riportato che i soggetti con IBD hanno un'aumentata rigidità arteriosa che può essere normalizzata dall'uso di farmaci anti TNF-alfa.
30
Bjarnegård, Niclas. "Aspects on wall properties of the brachial artery in man : with special reference to SLE and insulin-dependent diabetes mellitus". Doctoral thesis, Linköpings universitet, Institutionen för medicin och hälsa, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-11273.
Testo completoAbstract (sommario):
The mechanical properties of the arterial wall are of great importance for blood pressure regulation and cardiac load. With increasing age, large arteries are affected by increased wall stiffness. Furthermore, atherosclerotic manifestations may increase the stiffness even further, both processes acting as independent cardiovascular risk factors affecting the arterial system in a heterogeneous way. The aims of this thesis was to characterize the local mechanical properties of brachial artery (BA) with the aid of ultrasound technique and to evaluate the influence of 1) age, gender, sympathetic stimulation and examination site; 2) type 1 diabetes (DM) and its association to circulatory biomarkers; and 3) to evaluate the general properties of the arterial system with the aid of pulse wave velocity (PWV) as well as pulse wave analysis (PWA) in systemic lupus erythematosus (SLE) and correlate the findings to disease activity and circulatory biomarkers. In the most proximal arterial segment of the upper arm a pronounced age-related decrease in wall distensibility, increase in intima-media thickness (IMT), and a slight increase in diameter were seen. Sympathetic stimulation had no influence on wall mechanics. More distally in BA, no change in diameter, and only minor increase in IMT and decrease in distensibility were seen. No gender differences were found. These findings suggest that the principle transit zone between elastic and muscular artery behaviour is located in the proximal part of the upper arm. Women with uncomplicated insulin-dependent DM had similar diameter, IMT and distensibility in their distal BA as controls, whereas flow-mediated dilatation (FMD) was slightly, and nitrate mediated dilatation (NMD) markedly reduced. NMD was negatively correlated with higher HbA1c levels. Vascular smooth muscle cell function seems to be an early manifestation of vascular disease in women with DM, influenced by long-term hyperglycaemia. Women with SLE had increased aortic PWV compared to controls, a finding positively associated with increased levels of complement factor 3 (C3), but not with disease activity. The increased stiffness of central arteries may be one factor contributing to the increased cardiovascular risk seen in SLE.
31
Soukup, Ladislav. "Stanovení šíření pulzové vlny z dat celotělové bioimpedance". Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2021. http://www.nusl.cz/ntk/nusl-438883.
Testo completoAbstract (sommario):
This thesis deals with the methodology of use of whole-body impedance cardiography for evaluation of pulse wave velocity. The first three chapters explain selected hemodynamic properties of the arterial system related to the issue of pulse wave propagation. At the same time the ordinary methods for estimation, its disadvantages and merits has been summarized. Points at issue of whole-body impedance evaluation methodology for pulse wave velocity are researched in second part of this thesis. In order that analysis the procedure for correct methodology has been determined. Particularly determination of reference proximal point for calculation of transit time towards aortic valve, and design and accuracy of transit distance measurement were discussed. Based on the obtained data, a calculation of representative pulse wave velocity to eight limb locations was performed.
32
Miljkovic, Darko. "Corrélation entre la pression artérielle périphérique et la vitesse d'onde de pouls chez des sujets de plus de 80 ans institutionnalisés". Thesis, Université de Lorraine, 2013. http://www.theses.fr/2013LORR0113/document.
Testo completoAbstract (sommario):
Rationnel : La vitesse d'onde de pouls (VOP) est une méthode non invasive d'estimation de la rigidité artérielle. Les recommandations internationales établissent que la VOP est un marqueur puissant du risque cardiovasculaire (CV). La corrélation entre la pression artérielle périphérique et la VOP et leurs influences respectives sur la mortalité ont été peu étudiés chez les sujets âgés. Notre objectif était d'analyser cette corrélation chez les sujets institutionnalisés de plus de 80 ans. Méthodes : PARTAGE (valeur prédictive de la pression artérielle et de la rigidité artérielle chez institutionnalisé la population très âgée) est une étude de cohorte suivant pendant 2 ans 1130 sujets de plus de 80 ans institutionnalisés dans 72 centres en France et en Italie. La corrélation entre pression artérielle systolique et diastolique (PAS et la PAD) et la VOP (mesuré avec un tonomètre PulsePen ®) a été étudié chez 1071 sujets ayant des données de VOP. Résultats : La corrélation entre la PA et la VOP dans notre étude est significative mais faible. Les coefficients de corrélation sont de 0,24 pour la corrélation PAS clinique-VOP, 0,26 pour la corrélation PP-VOP, et 0,30 pour la corrélation PA automesure-VOP. La corrélation est systématiquement plus élevée chez les femmes mais sans atteindre la significativité. Le niveau de corrélation est inversement proportionnel à l'âge : les corrélations les plus fortes sont retrouvées dans la population la plus jeune. Le traitement antihypertenseur n'a pas d'impact sur la corrélation. Conclusion : La faiblesse de la corrélation montre que la PA et la VOP expriment différents phénomènes physiopathologiques de la rigidité artérielle. L'analyse longitudinale de l'étude PARTAGE, mise en perspective avec ceux trouvés dans nos travaux, pourraient permettre de proposer la VOP comme une méthode complémentaire, voire alternative, à la mesure de la PA dans l'évaluation du risque CV dans la population des sujets très âgésBackground: Carotid-femoral pulse wave velocity (PWV) provides a comprehensive non-invasive assessment of arterial stiffness. PWV is now established as a strong marker of cardiovascular disease. The correlation between peripheral blood pressure and PWV and their respective influences on mortality have been poorly studied in the elderly. Our objective was to analyze this correlation in nursing home residents over 80 years of age. Results could ultimately be helpful in implementing strategies for diagnosis and long-term follow-up of the very elderly population. Methods: The PARTAGE (Predictive value of blood pressure and ARTerial stiffness in institutionalized very AGEd population) study is a 2-year cohort study of 1130 subjects living in 72 nursing homes in France and Italy. The correlation between baseline systolic and diastolic blood pressure (SBP and DBP) and baseline PWV (measured with a PulsePen® tonometer) was studied in 1071 subjects with available PWV measurements. Results: Correlations between peripheral blood pressure and PWV were significant but weak: r=0.24 for self-measured SBP, r=0.30 for casual SBP, r=0.11 for self measured DBP, r=0.14 for casual DBP and r=0.26 for casual pulse pressure (PP). A trend for a weaker correlation was observed in the higher age group for self measured SBP and in the lower ADL group for self measured SBP and DBP. The correlations were systematically higher in women compared to men (but did not reach statistical significance) and lower with advanced age group. The correlation was not impacted by antihypertensive. Conclusion: These findings suggest that SBP, DBP and PWV provide different information in the very elderly. The prospective, longitudinal, long term PARTAGE study results will allow further insight; provide additional in-depth information regarding the respective prognostic value of these two measurement methods. NCT00901355
33
Goudot, Guillaume. "Applications innovantes des ultrasons en pathologie vasculaire : utilisation de l'imagerie ultrarapide dans l'analyse de la rigidité artérielle et des ultrasons pulsés en thérapie Arterial stiffening assessed by ultrafast ultrasound imaging gives new insight into arterial phenotype of vascular Ehlers–Danlos mouse models Aortic wall elastic properties in case of bicuspid aortic valve Segmental aortic stiffness in bicuspid aortic valve patients compared to first-degree relatives Wall shear stress measurement by ultrafast vector flow imaging for atherosclerotic carotid stenosis Pulsed cavitational therapy using high-frequency ultrasound for the treatment of deep vein thrombosis in an in vitro model of human blood clot". Thesis, Sorbonne Paris Cité, 2018. https://wo.app.u-paris.fr/cgi-bin/WebObjects/TheseWeb.woa/wa/show?t=2215&f=13951.
Testo completo
34
Mezuláníková, Radka. "Vyhodnocení rychlosti šíření tlakové vlny v lidském těle". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2013. http://www.nusl.cz/ntk/nusl-220037.
Testo completoAbstract (sommario):
This Mater's thesis deals with the evaluation of pulse wave velocity using multi-channel whole-body impedance cardiography. Data were taken from the group of healthy volunteers whose impedance changes were measured during rest, respiratory maneuvers, tilt and stress exercise. The result of this measurement are values of peaks of pulse wave time shifts towards R-wave. The velocity values towards the thorax electrodes were recalculated on the basis of knowledge about the pulse wave time shifts and the distances from the heart to the scanned locations, which were measured using the arterial segment's lengths.
35
Pizzi, Oswaldo Luiz. "Velocidade da onda de pulso em adultos jovens acompanhados por 18 anos: impacto de variáveis pressóricas, antropométricas, metabólicas, inflamatórias e de função endotelial. Estudo do Rio de Janeiro". Universidade do Estado do Rio de Janeiro, 2013. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=4851.
Testo completoAbstract (sommario):
Dados sobre a avaliação não invasiva da rigidez vascular e suas relações com variáveis de risco cardiovascular são escassos em jovens. Objetiva avaliar a relação entre a velocidade de onda de pulso (VOP) e a pressão arterial (PA),
variáveis antropométricas, metabólicas, inflamatórias e de disfunção endotelial em indivíduos adultos jovens. Foram estudados 96 indivíduos (51 homens) do Estudo do Rio de Janeiro, em duas avaliações, A1 e A2, com intervalo de 17,691,58 anos (16 a 21 anos). Em A1 foram avaliados em suas escolas (10-15 anos - média 12,421,47 anos) e em A2 foram novamente avaliados em nível ambulatorial (26-35
anos - média 30,091,92 anos). Em A1 foram obtidos pressão arterial (PA) e índice de massa corporal (IMC). Em A2 foram obtidos a velocidade da onda de pulso (VOP)-método Complior, PA, IMC, circunferência abdominal (CA), glicose, perfil lipídico, leptina, insulina, adiponectina, o índice de resistência à insulina HOMA-IR, proteína C-Reativa ultrassensível (PCRus) e as moléculas de adesão E-selectina,
Vascular Cell Adhesion Molecule-1(VCAM-1) e Intercellular Adhesion Molecule-1 (ICAM-1). Foram obtidos, ainda, a variação da PA e do IMC entre as 2 avaliações. Em A2 os indivíduos foram estratificados segundo o tercil da VOP para cada sexo. Como resultados temos: 1) Os grupos foram constituídos da seguinte forma: Tercil 1:homens com VOP < 8,69 m/s e mulheres com VOP < 7,66 m/s; Tercil 2: homens
com VOP ≥ 8,69 m/s e < 9,65m/s e mulheres com VOP ≥ 7,66 m/s e < 8,31m/s;Tercil 3:homens com VOP ≥ 9,65 m/s e mulheres com VOP ≥ 8,31 m/s. 2) O grupo com maior tercil de VOP mostrou maiores médias de PA sistólica (PAS) (p=0,005), PA diastólica (PAD) (p=0,007), PA média (PAM) (p=0,004), variação da PAD (p=0,032), variação da PAM (p=0,003), IMC (p=0,046), variação do IMC (p=0,020), insulina (p=0,019), HOMA-IR (p=0,021), E-selectina (p=0,032) e menores médias de adiponectina (p=0,016), além de maiores prevalências de diabetes mellitus/intolerância à glicose (p=0,022) e hiperinsulinemia (p=0,038); 3) Houve correlação significativa e positiva da VOP com PAS (p<0,001), PAD (p<0,001), PP (p=0,048) e PAM (p<0,001) de A2, com a variação da pressão arterial (PAS, PAD e PAM) (p<0,001) entre as duas avaliações, com o IMC de A2 (p=0,005) e com a variação do IMC (p<0,001) entre as duas avaliações, com CA (p=0,001), LDLcolesterol
(p=0,049) e E-selectina (p<0,001) e correlação negativa com HDLcolesterol (p<0,001) e adiponectina (p<0,001); 4)Em modelo de regressão múltipla, após ajuste do HDL-colesterol, LDLcolesterol e adiponectina para sexo, idade, IMC e PAM, apenas o sexo masculino e a PAM mantiveram correlação significativa com a VOP. A VOP em adultos jovens mostrou relação significativa com variáveis de risco
cardiovascular, destacando-se o sexo masculino e a PAM como importantes variáveis no seu determinismo. Os achados sugerem que a medida da VOP pode ser útil para a identificação do acometimento vascular nessa faixa etária.Data on non-invasive evaluation of vascular stiffness in the young and its relationship with cardiovascular (CV) risk variables are scarce. Objective to assess the relationship between pulse wave velocity (PWV) and blood pressure (BP), anthropometric, metabolic, inflammatory and endothelial dysfunction variables in young adults. Ninety-six individuals (51 males) from The Rio de Janeiro Study cohort were studied in two evaluations, A1 and A2, with an interval of 17.69 1.58 years (16-21 years). In A 1 they were evaluated at their schools (10-15 years average 12.42 1.47 years) and in A2 they were all re-evaluated as outpatients (26-35 years - average 30.09 1.92 years). In A1 BP and body mass index (BMI) were obtained. In A2 pulse wave velocity (PWV) by Complior method, BP, BMI, waist circumference (WC), glucose, lipid profile, leptin, insulin, adiponectin, the HOMA-IR insulin resistance index, high sensitive C-Reactive protein (CRPhs) and E-selectin, Vascular Cell Adhesion Molecule 1 (VCAM-1) and Intercellular Adhesion Molecule 1 (ICAM-1) adhesion molecules were obtained. The BP and BMI variation over the time interval between the two evaluations were also obtained. Subjects were stratified according to tertile of PWV for each sex in A2. As results: 1) The groups were constituted as follows: Tertile 1: males with PWV <8.69 m/s and females with PWV <7.66 m/s; Tertile 2: males with PWV ≥ 8.69 m/s and <9.65 m/s and females with PWV ≥ 7.66 m/s and <8.31 m/s; Tertile 3: males with PWV ≥ 9.65 m/s and females with PWV ≥ 8.31 m/s 2) The group with the highest PWV tertile showed higher values of systolic BP (SBP) (p=0.005), diastolic BP (DBP) (p=0.007), mean BP (MBP) (p=0,004), DBP variation (p=0,032), MBP variation (p=0.033), BMI (p=0.046), BMI variation (p=0.020), insulin (p=0.019), HOMA-IR (p=0.021), E-Selectin (p=0.032) and lower values of adiponectin (p=0.016), besides higher prevalence of diabetes mellitus/glucose intolerance (p=0.022) and hyperinsulinemia (p=0.038); 3) There were a significant positive correlation of PWV with SBP (p<0,001), DBP (p<0,001), PP (p=0,048) and MBP (p<0,001) from A2, variation in blood pressure (SBP, DBP, and MBP) (p<0,001) between the two assessments, BMI (p=0.005) and BMI variation between the two evaluations (p<0,001), WC (p=0.001), LDL-cholesterol (0.049), and E-selectin (p<0,001) and negative correlation with HDL-cholesterol (p<0,001) and adiponectin (p<0,001); 4) In the multiple regression model, HDL-cholesterol, LDL-cholesterol and adiponectin lost statistical significance after adjustment for sex, age, BMI and MBP, only the male gender and MBP remained significantly correlated with PWV. PWV in young adults showed a significant association with CV risk variables, highlighting the male gender and MBP as important variables in its determining. The findings suggest that measurement of PWV can be useful for the identification of vascular impairment in this age group.
36
Rezailashkajani, Mohammadreza. "Cardiovascular risk in ageing men of different ethnicities : inter-relationships between imaging and endocrine markers". Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/cardiovascular-risk-in-ageing-men-of-different-ethnicities-interrelationships-between-imaging-and-endocrine-markers(504c0fa3-280e-4206-94b6-e6093fb5e87b).html.
Testo completoAbstract (sommario):
Cardiovascular disease varies by ethnicity in the UK. South Asians (SA) have higher coronary heart disease (CHD) and diabetes prevalence, while African-Caribbeans (AfC) have greater stroke, but intriguingly lower CHD rates despite higher blood pressures and diabetes risk than Europeans. Conventional risk factors do not fully explain such differences. This cross-sectional study tested the hypothesis that the hormones, vitamin D measured as 25(OH)D and aldosterone, would be independently associated with intermediate cardiovascular outcome markers in these ethnic groups. Community-dwelling men 40-80 years old (AfC: n=67, 55±10yr; SA: n=68, 55±10yr; European: n=63, 57±8yr) were sampled from Greater Manchester’s multi-ethnic population. The intermediate markers examined were aortic pulse wave velocity (aPWV), left ventricular (LV) mass and function, and carotid intima media thickness (CIMT), measured non-invasively by ultrasound, and hemodynamic profiling methods (the Arteriograph) in the total sample and by magnetic resonance imaging (MRI) in a subsample of 50. Adjusted for age, systolic blood pressure and diabetes, mean(SE) aPWV by the Arteriograph, was 0.5(0.2) m/s higher in SA than AfC and Europeans (p=0.01), which paralleled known cross-ethnic CHD risk differences in the UK. By MRI, aPWV along the descending aorta in SA was 0.7(0.3) and 0.8(0.3) m/s higher than that in AfC and Europeans, but aPWV along the aortic arch was not significantly different. Unlike aldosterone, 25(OH)D was independently and inversely correlated with aPWV (unstandardised B(SE)=-0.013[0.004] m/s, p<0.001), and partly explained the ethnic variation in aPWV. Similar inverse correlations were found between 25(OH)D and LV concentricity measured by echocardiography and MRI. Compared to Europeans, SA and AfC, had 21(3) and 14(3) nmol/L lower mean(SE) 25(OH)D, respectively (p<0.01). Mean(SE) of relative wall thickness, an index of LV concentricity by echocardiography, was 0.05(0.01) higher in SA and AfC than Europeans. Lower 25(OH)D levels were also associated with higher myocardial deformation rates measured by MRI myocardial tagging (n=50), supporting previous animal experimental evidence. A one standard deviation (SD) decrease in 25(OH)D was associated with a 0.38 SD increase in absolute systolic strain rate (p=0.003) and 0.22 SD rise in diastolic strain rate (p=0.04). Right and left CIMT showed different relations with 25(OH)D and aldosterone. Left-right CIMT differences varied by ethnicity and were related to SA ethnicity and aldosterone levels. Two related technical studies investigated the relatively new method of hemodynamic profiling, the Arteriograph, used here. The results suggested a standardisation method of aortic length estimation for purely central aPWV, which significantly improved aPWV agreement between the Arteriograph and MRI (reference method here), and was used for calibrating the Arteriograph aPWV in the above-mentioned results for the total sample. Future well-designed trials are necessary to investigate any cause-effect relationship between vitamin D deficiency and the unfavourable cardiovascular intermediate outcomes found here in a cross-sectional design and multi-ethnic background.
37
Cabeleira, Manuel Teixeira. "Optical measurement of the arterial pulse wave and determination of pulse wave velocity". Master's thesis, 2010. http://hdl.handle.net/10316/14154.
Testo completoAbstract (sommario):
Actualmente o sedentarismo e maus hábitos alimentares da generalidade da população dos países
desenvolvidos promove o aumento de casos de doenças cardiovasculares. A percentagem de mortes
causadas por estas doenças aumenta todos os dias e é agora a maior causa de morte nestes países. Por
esta razão, a detecção de complicações cardiovasculares adquiriu um papel de relevância e nas últimas
décadas tem sido feita uma grande aposta no desenvolvimento de novos métodos de detecção. Como
consequência novos parâmetros, como velocidade da onda de pulso (VOP) e índice de aumentação são
presentemente usados para avaliar o risco cardiovascular.
No decorrer deste projecto, sondas ópticas capazes de gravar a onda de pressão arterial foram
desenvolvidas e testadas. Nestas sondas dois fotodíodos, separados 3 cm, foram usados como sensores e
devido à sua configuração (das sondas) foi possível medir a VOP local na carótida humana. Os dados
recolhidos eram medidas directas da onda de pressão. Os algoritmos desenvolvidos avaliaram
satisfatoriamente o desfasamento temporal entre os sinais recebidos por cada fotodíodo e calcularam a
VOP correspondente.
De forma a validar os algoritmos e as sondas anteriormente mencionados foram montadas três
bancadas de teste capazes de simular a referida onda de pressão e a suas propriedades de propagação.
38
Wang, Shih-fan, e 王仕帆. "The Design of Pulse Wave Velocity Detector". Thesis, 2012. http://ndltd.ncl.edu.tw/handle/73379401731257581718.
Testo completo
39
Ji-Shiang, Weng, e 翁基翔. "Pulse Wave Velocity Measurement Platform Using Dual-Processors". Thesis, 2005. http://ndltd.ncl.edu.tw/handle/68493420481580270583.
Testo completoAbstract (sommario):
碩士南台科技大學
資訊工程系
93
According to the “The World Healthy Report 2002”, which reported by the World Healthy Organization, approximately 69 percent of adults who aged over 60 died of atherosclerosis. Reflection Index (RI), Stiffness Index (SI) and Pulse Wave Velocity (PWV) are correlative parameters, which are used to evaluate the atherosclerosis degrees. PWV had been demonstrated to correlate with characteristics of blood vessel in the many research reports. Pressure gauge and ultrasonic sensor were used to acquire sphygmogram in some clinical instruments. However, pressure gauge and ultrasound are too expensive and them need to be operated by professional clinician. Therefore, infrared sensors are used to determine the sketch of pulse wave in this study. Photoplethysmography (PPG) is acquired by infrared sensor. This study proposes a platform based on dual-processors, which utilizes infrared sensor acquiring PPG signal and translates the PPG signal into the Digital Volume Pulse (DVP). The system can be used to analyze the feature point by a high performance digital signal processor.
40
Agala, D. "Evaluation of pulse wave velocity in rheumatoid arthritis". Thesis, 2014. http://essuir.sumdu.edu.ua/handle/123456789/35754.
Testo completoAbstract (sommario):
The measurement of pulse wave velocity (PWV) is one of the important methods to identify the elasticity properties of arteries. Arterial stiffness is an independent risk factor of cardiovascular disease.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35754
41
Chen, Liang-Hung, e 陳亮宏. "A Single-arm Pulse-wave Velocity Measurement System". Thesis, 2016. http://ndltd.ncl.edu.tw/handle/30808603066154806654.
Testo completoAbstract (sommario):
碩士國立中央大學
電機工程學系
104
Most of the current commercial electronic sphygmomanometers use the oscillometric method. The oscillometic method occludes blood flow by using the inflatable cuff, and using a piezoelectric pressure sensor to detected the pulsatility in arterial wall. To improve the user’s comfort and monitor the short term trend of blood pressure, in recent years, some researchers propose a novel cuffless blood pressure measurement system by using the pulse wave velocity (PWV) technique. These measurement system measure Lead I ECG from both hands and the fingertip PPG, and then calculate the Systolic blood pressure (SBP) by compute the time delay between the electrocardiogram (ECG) R peak and the Photo-plethysmography (PPG) characteristics. However, the measurement of ECG from both hands is inconvenient and the clip of fingertip PPG is uncomfortable after long-time use. Therefore, in this study, we proposed a novel system by measuring single-arm ECG and wrist reflectance-based PPG. We first create a SBP estimation model from nine health subjects (mean ages = 25.1±4.3321 years-old), and the apply the model on ten normal subjects (mean ages = 41.6±14.2 years-old) and twelve hypertension patients (mean ages = 52.75±10.1 years-old). The estimated error in the ten normal subjects and the twelve hypertension patients are 1.71±1.34% and 5.71±4.54%, respectively, which demonstrate the feasibility of the proposed system. Future work will apply our method on wearable devices in order to provide a convenient and accurate way for long-term SBP monitoring.
42
陳冠廷. "The Analysis of Engineering Technology for Pulse Wave Velocity". Thesis, 2013. http://ndltd.ncl.edu.tw/handle/3u6fkj.
Testo completo
43
Chou, Kun-Shien, e 周坤賢. "Evaluation of Pulse Wave Velocity by Photoplethysmography and Electrocardiogram". Thesis, 2006. http://ndltd.ncl.edu.tw/handle/31885556313393826654.
Testo completoAbstract (sommario):
碩士南台科技大學
資訊工程系
94
Under the environment with developments of new technologies, modern medicine keeps advancing. Traditional concept of medical treatment is change gradually from cure after sick happen to pre-examination or pre-protection. Many researchers believe that prior evaluations of sick reasons and take early care can reduce dangers and possible complications. Pulse wave velocity (PWV) was correlated well with the degree of arteriosclerosis, and PWV can be one of parameters during clinical evaluation of arteriosclerosis. The study proposes a PWV measurement system that it can measure simultaneously the PWV, which form heart to four extremities by the location of electrocardiogram. The differences of the PWV, which from heart to four extremities, were observed and the comparisons of correlations were tested. Besides, the PWV were compared with the PWV, which from different sites (finger and toe). The differences of two evaluated PWV methods were also assessed. To improve the precision of measured value, the system with high sample rate during long-term measurement. The study expected to provide more complete method for evaluation of PWV, and to understand the differences between different measure methods.
44
Chen, Yung-kang, e 陳永康. "A novel system for detection of pulse wave velocity". Thesis, 2004. http://ndltd.ncl.edu.tw/handle/81863818346548314341.
Testo completoAbstract (sommario):
碩士南台科技大學
電子工程系
92
The purpose of this thesis is to implement a non-invasive measurement system that can be used to collect the digital volume pulse (DVP) from a finger and a toe simultaneously with penetration infrared sensors. From the DVP data, the pulse wave velocity (PWV) can be calculated in real-time by using a personal computer (PC) for doctors to determine the level of arterial stiffness of the patients. Although there are some drawbacks to using a dual channel system (versus the commonly used single channel), the system proposed in this paper uses real-time processing with better accuracy and reduced complexity. Our software algorithm locates the characteristic point (foot of the pulse wave) without assistance from an electrocardiogram (ECG). The complete system includes: the circuits of the infrared sensor, analog signal processing circuits and real-time analysis software based on a PC. For confirmation of clinical implications, the proposed system has been used in the clinical experiments about the level of arterial stiffness at National Cheng Kung University Medical Center. The clinical results have shown that the proposed system can be operated easily to determine arterial stiffness with high accuracy.
45
Chung-MinHuang e 黃崇珉. "Automatic Pulse Wave Velocity Measurement Using Phase Contrast MRI". Thesis, 2018. http://ndltd.ncl.edu.tw/handle/ry7ude.
Testo completo
46
Steinman, Aaron H. "Errors in phased array pulse-wave ultrasound velocity estimation systems". 2004. http://link.library.utoronto.ca/eir/EIRdetail.cfm?Resources__ID=80268&T=F.
Testo completo
47
Chen, Zong-Li, e 陳宗勵. "Measuring Six-channel Pulse Wave Velocity using ECG and Photoplethysmography". Thesis, 2010. http://ndltd.ncl.edu.tw/handle/56082221288295533312.
Testo completoAbstract (sommario):
碩士國立東華大學
電機工程學系
98
Department of Health published the cause of deaths and there are 26.5% with cardiovascular diseases. If we can to avoid the occurrence of risk factors and assess the degree of arterial stiffness that we can prevent cardiovascular disease place. Our laboratory previous design of the two arteriosclerosis measuring instruments (PWV-DVP and PWV-DVPE), respectively, by measuring hand－foot and ear－hand pulse wave velocity, the two instruments has been proven and existing atherosclerosis measurement instrument associated with the clinical sciences. Because of the measured reference point, there will be underestimating the degree of atherosclerosis the circumstance. In order to solve this problem, our laboratory research the ECG R-wave peak as the anchor point, and then combined volume of six groups of light sensing circuit made of six channels pulse wave velocity measuring device, and this system has proved in healthy people who have good results and reproducibility. But the equipment did not compare with the other instruments in the hospital and did not apply to the patients. We used a six-channels measuring instrument of atherosclerosis in healthy people and patients to do some studies. Separately with the Cardio-ankle vascular index and PWV-DVP the similar instrument makes the relevant comparison in the healthy subjects to test the relevance of parts, the study found the finger and the site of the toes has correlation in PWV values. In the trend part of the experimental, we found that when the ear parts of PWV higher, the hand and the foot PWV will be relatively high. Separately with the Initima-Media Thickness and PWV-DVP, the similar instrument makes the relevant comparison in the cardiovascular disease patients to test the relevance of parts, the study found position in the ears have a good relationship, we also found a six-channels measuring instrument indeed improved PWV-DVP and PWV-DVPE's missing in the assessment of atherosclerosis. In future, our lab will use this system in diabetic patients on the rain-depth analysis.
48
Ye, Shin-Ju, e 葉詩如. "Assessment of Pulse Wave Velocity Using Multi-Channel Measurement System". Thesis, 2007. http://ndltd.ncl.edu.tw/handle/88819058531463255169.
Testo completoAbstract (sommario):
碩士南台科技大學
資訊工程系
95
Pulse wave velocity (PWV) is one of many parameters, which is used to evaluate arteriosclerosis recently. Therefore, the goal of the study is to design an extremities-PWV evaluation system. The PWV is calculated by pulse characteristic-points search and first heart-sound location. It observes that the differences and relationships among the PWV. Because non-invasive arteriosclerosis evaluation by PWV is based on all pulse velocities are equal, it makes some unreasonable results. The proposal method in the study provides more careful evaluation of PWV, and compares the relationship between calculated two PWVs from heart-extremities and finger-toe respectively. It can provide the clinician reference, which makes arteriosclerosis evaluation. The user interface includes two components: signal-acquisition function and analytic-data function. The signal-acquisition function, which is designed by Visual Basic program language, can draw the multi-channel signals on the graphic interface and real-time calculate extremities-PWV. The analytic-data function, which is designed by Matlab program language, can beat-by-beat calculates physiological information conveniently. The system uses long-term electrocardiogram, heart sound and photoplethysmography simultaneous record, not only can provide more precise value but also can evaluate more complete PWV. Keyword: PWV, arterial stiffness, phonocardiogram
49
Chen, Yi-Wei, e 陳奕瑋. "Estimation of Pulse Wave Velocity using Cardiac Computer Tomography Image". Thesis, 2012. http://ndltd.ncl.edu.tw/handle/32274535977507687115.
Testo completoAbstract (sommario):
碩士中原大學
生物醫學工程研究所
100
Recent studies have shown that patients who have atherosclerosis would increase the risk of cardiovascular disease directly or indirectly. Total arterial compliance (TAC) is defined as the sum of systemic arterial compliance, and assessment of compliance for artery stiffness was usually used central aorta which is more elasticity than peripheral and closes to the heart. Pulse wave velocity (PWV) is an index for assessing the level of artery stiffness in clinic. The purpose of this study is to observe the volume changes in the aortic heart cycle to evaluate the arterial PWV. Observation and analysis of the cardiac computed tomography images of multiple timing characteristics for aortic parts. firstly, the reposition of the left ventricle in short axis view, the central axis of the 3D LV model was adjusted manually to be aligned with axis that was constructed using central point of short axis LV image from mitral valve to the apex of left ventricle. 2D Rotation formula for correctly positioning and image re-sampling. Then observe the physical location of the aorta in the chest. The active contour and the seeded region grow are two function to locate the edge contour of the aorta. Calculate the volume of the aorta to analyze the aortic PWV parameters. Pulse wave velocity is two waveforms formed by two different measurement positions of aortic of the area or volume. Considering a common reference point in the same cardiac cycle for the ratio of the difference in time between the difference in distance. This experiment utilized fifteen people to calculate the volume parameter. The volume verification and the aortic pulse conduction velocity differs with the degree of analysis. One verified the left ventricular stroke volume and the aorta flow, the left ventricular cardiac output is equal to the principle of the aortic flow in each heart cycle. To verify the accuracy of the left ventricular and aortic volume method used in this study, results shows that the relationship between the estimation of the left ventricular cardiac output of this study and the aortic cross-sectional area of flow is positive correlation (R = 0.970, P <0.01). Pulse Wave Velocity was the correlation with other vessel stiffness parameters and result showed that pulse wave velocity and arterial compliance were positive correlated (R=0.672，P<0.01) and the relation with dispensability was negative correlated (R=-0.8549，P<0.01) but the age was positive correlated (R=0.794、P<0.01).This study provides a use of non-invasive computed tomography image through the aortic volume change to assessment of aortic pulse wave velocity
50
Wang, Chih-Chin, e 王志進. "Measurement of Pulse Wave Velocity by Photoplethysmography Apply to Animals Analysis". Thesis, 2009. http://ndltd.ncl.edu.tw/handle/01627510173989955364.
Testo completoAbstract (sommario):
碩士南台科技大學
資訊工程系
97
Nowadays, the quality of our life improves greatly and our diet becomes better and better if compared to the past. Consequently, it is easier to get fat due to lack of exercise , working pressure , smoking , unhealthy diet habit and so on. However, fatness is one of the main reasons to cause the diseases of cardiovascular system. How do we prevent from the disease of cardiovascular ? The most important thing that we have to do first is to understand and find out what will cause the disease of cardiovascular. The cardiovascular disease is involved in the heart and blood vessel. These diseases are all related to the Arteriosclerosis. According to the statistics of The department of health (DOH), we can figure out that the diseases of cardiovascular always ranks high among the top ten causes of death ; moreover, there are more and more young people to get the problems of cardiovascular. Consequently, it is a very important issue of the prevention and treatment of cardiovascular diseases at present. In order to decrease the possibility of the cardiovascular diseases, we have to comprehend whether the artery is hardening or not. pulse wave velocity is the most important parameter which is used in evaluating the level of arteriosclerosis. Generally speaking, if the blood vessel is harder and the elasticity is worse, then the pulse wave velocity will be faster. In my thesis, I experimented on a mouse and surveyed the photoplethysmography from the palm and thenar of the mouse, and then I could calculate the pulse wave velocity and heart rate of the mouse for testing some treatment and reduce the possibility of arteriosclerosis. The research will be greatly helpful to who may investigate the artery and the other symptoms to these diseases. In addition, I programmed by Visual Basic 6.0 to collect and save photoplethysmography from the mouse’s palm and thenar and then read the data via the program by MATLAB 7.1. Finally, we can analyze the heart rate and pulse wave velocity of the mouse.