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1
Millasseau, Sandrine. "Arterial pulse wave analysis." Thesis, King's College London (University of London), 2003. https://kclpure.kcl.ac.uk/portal/en/theses/arterial-pulse-wave-analysis(5002b38b-53de-4c76-af89-db21c08fea68).html.
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Fok, Henry Wing Hang. "Ventricular-vascular coupling and central arterial pulse pressure." Thesis, King's College London (University of London), 2015. http://kclpure.kcl.ac.uk/portal/en/theses/ventricularvascular-coupling-and-central-arterial-pulse-pressure(c9b79392-15e3-4c43-b940-10bb9cbe35f7).html.
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Central pulse pressure (cPP), a product of ventricular-arterial interaction, is an important determinant of cardiovascular outcomes in hypertension. The aim of this thesis is to advance the understanding of pulsatile haemodynamics and to explore mechanisms that may selectively reduce cPP. The conventional view is that cPP comprises a component determined by the direct interaction of myocardial contraction with the impedance of the proximal arterial tree (closely related to pulse wave velocity, PWV) and a component ‘augmentation pressure’ generated by pressure wave reflections from muscular conduit arteries. Surprisingly little is known regarding regulation of conduit artery tone despite its potential influence on cPP. In the first part of this thesis, muscular large arterial tone was examined using a human forearm blood flow model. Vasoactive substances were infused locally into the brachial artery and vasodilator responses of the radial artery, as a muscular conduit artery, and forearm resistance microvasculature were examined. Nitric oxide donors, in particular, glyceryl trinitrate (GTN) were found to have the most selective action on conduit arteries compared to other vasodilators. In the second part of the thesis, I examined whether the action of GTN to reduce augmentation pressure could be accounted for by this selective dilation of muscular arteries. GTN was given systemically and by intra-coronary infusion in patients undergoing cardiac catheterisation. Invasive aortic blood pressure and flow velocity were analysed in the time domain by wave intensity analysis. This allows separation of pressure into a forward component generated by myocardial contraction and a backward component generated by ‘reflection’ from the peripheral arterial tree. A surprising finding was that changes induced by GTN were mainly attributable to a reduction in forward rather than backward pressure waves. That this resulted from a change in myocardial contractility was confirmed by local intracoronary injection of GTN. The final part of the thesis examines the relative contribution of forward and backward pressure waves in hypertension. An elevated cPP in hypertensive compared to normotensive subjects was accounted for primarily by an increased forward pressure wave. That this was due to increased myocardial contractility was confirmed by examining whether the pattern of wave intensity seen in hypertension could be reproduced, in normotensive subjects, by the inotrope dobutamine (when compared to the vasoconstrictor norepinephrine used as a control). This thesis thus provides novel insight into a) regulation of conduit artery tone, and b) pulsatile haemodynamics, highlighting the contribution of left ventricular ejection characteristics in determining pressure augmentation and cPP.
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de, Kock J. P. "Pulse oximetry : theoretical and experimental models." Thesis, University of Oxford, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302928.
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Ehrlich, Elizabeth R. "Sex Differences in Arterial Destiffening with Weight Loss." Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/43707.
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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.<br>Master of Science
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Smithers, Breana Gray. "Evaluating the Pulse Sensor as a Low-Cost and Portable Measurement of Blood Pulse Waveform." Thesis, University of North Texas, 2016. https://digital.library.unt.edu/ark:/67531/metadc849682/.
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This study was aimed at determining whether the digital volume pulse waveform using the Pulse Sensor can be used to extract features related to arterial compliance. The Pulse Sensor, a low-cost photoplethysmograph, measures green light reflection in the finger and generates output, which is indicative of blood flow and can be read by the low-cost Arduino UNO™. The Pulse Sensor code was modified to increase the sampling frequency and to capture the data in a file, which is subsequently used for waveform analysis using programs written in the R system. Waveforms were obtained using the Pulse Sensor during two 30-s periods of seated rest, in each of 44 participants, who were between the ages of 20 and 80 years. For each cardiac cycle, the first four derivatives of the waveform were calculated and low-pass filtered by convolution before every differentiation step. The program was written to extract 19 features from the pulse waveform and its derivatives. These features were selected from those that have been reported to relate to the physiopathology of hemodynamics. Results indicate that subtle features of the pulse waveform can be calculated from the fourth derivative. Feature misidentification occurred in cases of saturation or low voltage and resulted in outliers; therefore, trimmed means of the features were calculated by automatically discarding the outliers. There was a high efficiency of extraction for most features. Significant relationships were found between several of the features and age, and systolic, diastolic, and mean arterial blood pressure, suggesting that these features might be employed to predict arterial compliance. Further improvements in experimental design could lead to a more detailed evaluation of the Pulse Sensor with respect to its capability to predict factors related to arterial compliance.
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Eck, Vinzenz Gregor. "Arterial Flow and Pulse Wave Propagation in one dimensional Arterial Networks with Statistically Distributed Model Parameters." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for konstruksjonsteknikk, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-19311.
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Parametric uncertainty in blood flow simulations of cardiovascular systems has received little attention, although methods for blood flow simulation has been subject of many studies. This work presents the implementation and assessment of a method for one dimensional flow and pressure wave simulations in arterial networks with statistically distributed model parameters. The pressure and flow waves in the arterial system are characterized by means of cross-sectionally averaged 1D governing equations for mass and momentum, discretized with a MacCormack scheme (explicit and second order in time and space). The stochastic model considered is a combination of a generalized polynomial chaos with a stochastic collocation method and joined with the one dimensional model. The implementation is validated with the simulation of a single arterial bifurcation, which has been published by others previously, with a somewhat different approach. The assessment is completed with a sensitivity analysis of the wave dynamics, in particular reflected waves, in the systemic arterial tree in the context of ageing. The numerical simulations showed that the impact of model uncertainty in different compartments of the arterial tree on systolic and diastolic pressure peaks can be determined with the elaborated method. In particular, the uncertainty in material parameters of the aortic arch showed a strong influence on the pressure wave forms.
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Payne, Rupert Alistair. "Pulse transit time and the pulse wave contour as measured by photoplethysmography : the effect of drugs and exercise." Thesis, University of Edinburgh, 2009. http://hdl.handle.net/1842/5950.
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Photoplethysmography (PPG) is a simple means of measuring the pulse wave in humans, exploitable for the purposes of timing the arrival of the pulse at a particular point in the arterial tree, and for pulse contour analysis. This thesis describes a methodology for measuring arterial pulse transit time (PTT) from cardiac ejection to pulse arrival at the finger. It describes the effect on PTT of drug and exercise induced changes in BP. The nature of the relationship between the PPG and arterial pressure is also examined, and the PTT technique extended to assessment of conduit vessel pulse wave velocity (PWV) during exercise. PTT measured from ECG R-wave to PPG finger wave (rPTT) had a negative correlation (R2=0.39) with systolic BP (SBP), unaffected by vasoactive drugs in some but not all persons. rPTT showed similar beat-to-beat variability to SBP, unaffected by drugs. rPTT correlated weakly with diastolic (DBP) and mean (MAP) pressure. Cardiac pre-ejection period (PEP) formed a substantial and variable part of rPTT (12% to 35%). Transit time adjusted for PEP (pPTT) correlated better with DBP (R2=0.41) and MAP (R2=0.45), than with SBP. The PPG wave tracked changes in the peripheral pressure wave. Drugs had little effect on the generalised transfer function (GTF) describing the association between arterial and PPG waves. Strenuous exercise induced a large decrease in rPTT, mainly accounted for by decreases in PEP (53% of the total change in rPTT) and in transit time from aorta to distal brachial artery (33%). In contrast, minimal change in transit time from wrist to finger tip occurred with exercise. Simultaneous ear-finger PPG signals were used to measure conduit artery PWV during exercise. Ear-finger PWV (PWVef) overestimated carotid-radial PWV throughout exertion (overall bias 0.81±1.05ms-1, p<0.001), but the degree of difference remained constant. The increase in PWVef with exercise, was greater (1.18±0.54ms-1, p=0.035) in healthy subjects with a positive cardiovascular family history compared to those without. PPG enables analysis of the pulse contour during exercise, but estimation of the radial pressure wave from finger PPG by use of a GTF derived at rest, resulted in inaccuracy following exertion. These effects were variable and relatively short-lived. Furthermore, a resting GTF used to determine central pressure from the peripheral wave, resulted in underestimation of SBP (-5.9±2.1mmHg) and central pressure augmentation index (-8.3±2.9%), which persisted for 10 minutes post-exercise. rPTT had a negative linear association with SBP (R2=0.94) during strenuous exercise, slightly stronger than during recovery (R2=0.85). Differences existed in area-undercurve of the rPTT/SBP relationship between exercise and recovery, due to discrepancies in rate and degree of recovery of SBP and PEP. The linear relationship between the rPTT/SBP during exercise was affected by aerobic capacity, and the regression slope was less in the anaerobic compared to aerobic phase of exercise due to minimal change in PEP during anaerobic exertion. The correlation between rPTT/SBP did not change with prolonged aerobic exercise. Finally, measures of baroreflex sensitivity during exercise, were not significantly different between actual beat-to-beat SBP and SBP estimated using rPTT. In conclusion, absolute BP cannot be reliably estimated by measurement of rPTT following administration of drugs and during exercise. However, rPTT may have a role in measuring BP variability and in the assessing exercise capacity. PPG may also be useful in determining the effects of exercise on arterial stiffness, and for estimating the pressure wave contour, although its use during exercise for the latter purpose must be treated with caution.
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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.
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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.<br>Applied Science, Faculty of<br>Engineering, School of (Okanagan)<br>Graduate
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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.
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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.
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Zhang, Ruizhi. "ARTERIAL WAVEFORM MEASUREMENT USING A PIEZOELECTRIC SENSOR." VCU Scholars Compass, 2010. http://scholarscompass.vcu.edu/etd/126.
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This study aims to develop a new method to monitor peripheral arterial pulse using a PVDF piezoelectric sensor. After comparing different locations of sensor placement, a specific sensor wrap for the finger was developed. Its composition, size, and location make it inexpensive and very convenient to use. In order to monitor the effectiveness of the sensor at producing a reliable pulse waveform, a monitoring system, including the PZT sensor, ECG, pulse-oximeter, respiratory sensor, and accelerometer was setup. Signal analysis from the system helped discover that the PZT waveform is relative to the 1st derivative of the artery pressure wave. Also, the system helped discover that the first, second, and third peaks in PZT waveform represent the pulse peak, inflection point, and dicrotic notch respectively. The relationship between PZT wave and respiration was also analyzed, and, consequently, an algorithm to derive respiratory rate directly from the PZT waveform was developed. This algorithm gave a 96% estimating accuracy. Another feature of the sensor is that by analyzing the relationship between pulse peak amplitude and blood pressure change, temporal artery blood pressure can be predicted during Valsalva maneuver. PZT pulse wave monitoring offers a new type of pulse waveform which is not yet fully understood. Future studies will lead to a more broadly applied use of PZT sensors in cardiac monitoring applications.
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Hall, Ian Robert. "An assessment of arterial stiffness and endothelial function using pulse wave analysis." Thesis, Cardiff University, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.423042.
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Chan, Gregory Electrical Engineering & Telecommunications Faculty of Engineering UNSW. "Early detection of blood loss using a noninvasive finger photoplethysmographic pulse oximetry waveform." Publisher:University of New South Wales. Electrical Engineering & Telecommunications, 2008. http://handle.unsw.edu.au/1959.4/42593.
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Delayed control of haemorrhage or blood loss has been recognised as a major contributor to preventable trauma deaths, but early detection of internal bleeding is difficult due to unreliability of heart rate (HR) and blood pressure (BP) as markers of volume status. This thesis explores a novel method of early blood loss detection using a noninvasive finger photoplethysmographic (PPG) pulse oximetry waveform that is normally utilised in pulse oximeters for estimating arterial oxygen saturation. Graded head-up tilt (n = 13) and blood donation (n = 43) in human volunteers were selected as experimental models of mild to moderate blood loss. From the tilt study, a novel method for automatically detecting left ventricular ejection time (LVET) from the finger PPG waveform has been developed and verified by comparison with the LVET measured from aortic flow velocity. PPG waveform derived LVET (LVETp) and pulse transit time (PTT) were strongly correlated with aortic LVET and pre-ejection period respectively (median r = 0.954 and 0.964) and with the decrease in central blood volume indicated by the sine of the tilt angle (median r = -0.985 and 0.938), outperforming R-R interval (RRI) and BP in detecting mild central hypovolaemia. In the blood donation study, progressive blood loss was characterised by falling LVETp and rising PTT (p < 0.01). A new way of identifying haemorrhagic phases by monitoring changes and trends in LVETp, PTT and RRI has been proposed based on the results from the two studies. The utility of frequency spectrum analysis of PPG waveform variability (PPGV) in characterising blood loss has also been examined. A new technique of PPGV analysis by computing the coherence-weighted cross-spectrum has been proposed. It has been shown that the spectral measures of finger PPGV exhibited significant changes (p < 0.01) with blood donation and were mildly correlated with systemic vascular resistance in intensive care unit patients (r from 0.53 to 0.59, p < 0.0001), therefore may be useful for identification of different haemorrhagic phases. In conclusion, this thesis has established finger PPG waveform as a potentially useful noninvasive tool for early detection of blood loss.
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Walsh, Andrew Michael Graduate school of biomedical engineering UNSW. "Application of supervised and unsupervised learning to analysis of the arterial pressure pulse." Awarded by:University of New South Wales. Graduate school of biomedical engineering, 2006. http://handle.unsw.edu.au/1959.4/24841.
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This thesis presents an investigation of statistical analytical methods applied to the analysis of the shape of the arterial pressure waveform. The arterial pulse is analysed by a selection of both supervised and unsupervised methods of learning. Supervised learning methods are generally better known as regression. Unsupervised learning methods seek patterns in data without the specification of a target variable. The theoretical relationship between arterial pressure and wave shape is first investigated by study of a transmission line model of the arterial tree. A meta-database of pulse waveforms obtained by the SphygmoCor"??" device is then analysed by the unsupervised learning technique of Self Organising Maps (SOM). The map patterns indicate that the observed arterial pressures affect the wave shape in a similar way as predicted by the theoretical model. A database of continuous arterial pressure obtained by catheter line during sleep is used to derive supervised models that enable estimation of arterial pressures, based on the measured wave shapes. Independent component analysis (ICA) is also used in a supervised learning methodology to show the theoretical plausibility of separating the pressure signals from unwanted noise components. The accuracy and repeatability of the SphygmoCor?? device is measured and discussed. Alternative regression models are introduced that improve on the existing models in the estimation of central cardiovascular parameters from peripheral arterial wave shapes. Results of this investigation show that from the information in the wave shape, it is possible, in theory, to estimate the continuous underlying pressures within the artery to a degree of accuracy acceptable to the Association for the Advancement of Medical Instrumentation. This could facilitate a new role for non-invasive sphygmographic devices, to be used not only for feature estimation but as alternatives to invasive arterial pressure sensors in the measurement of continuous blood pressure.
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Teren, Andrej, Frank Beutner, Kerstin Wirkner, Markus Löffler, and 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.
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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.
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Keeler, Jason Michael. "PREDICTORS OF ARTERIAL STIFFNESS IN LAW ENFORCEMENT OFFICERS." UKnowledge, 2018. https://uknowledge.uky.edu/khp_etds/48.
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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.
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Neto, Nilton Salles Rosa. "Avaliação não invasiva das propriedades estruturais de grandes artérias em pacientes com arterite de Takayasu." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/5/5164/tde-16092013-151428/.
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A Arterite de Takayasu (AT) é uma vasculite granulomatosa de aorta e grandes vasos associada a elevado risco cardiovascular. A velocidade de onda de pulso (VOP) é um método de avaliação indireta de diminuição da distensibilidade arterial, e valores elevados de VOP correlacionam-se com maior morbimortalidade cardiovascular. A avaliação da VOP em pacientes com arterite de Takayasu é complexa devido a muitos fatores de confusão. O objetivo do presente estudo foi avaliar a rigidez arterial, por meio da velocidade de onda de pulso carótido-femoral (VOP-CF) em pacientes do sexo feminino com arterite de Takayasu e controles saudáveis com variáveis clínicas e antropométricas comparáveis, e sua possível associação com os parâmetros da doença. Método: Pacientes com arterite de Takayasu (n = 27) foram avaliados consecutivamente e foram selecionados controles saudáveis com idade, pressão arterial, peso e altura comparáveis (n = 27). Os critérios de exclusão foram menopausa, tabagismo, diabetes, insuficiência renal, hipertensão mal controlada, arritmias cardíacas, obesidade, comorbidades inflamatórias, gravidez e história de procedimentos cirúrgicos que envolvessem a aorta. A atividade da doença foi determinada por parâmetros clínicos e laboratoriais. As medições de VOP-CF foram obtidas pelo Sistema Complior. Resultados: A média de VOP-CF foi maior em pacientes com arterite de Takayasu do que em controles (9,77 ± 3,49 vs. 7,83 ± 1.06 m/s, p = 0,009). Apesar dos rigorosos xv critérios de seleção, os pacientes com arterite de Takayasu ainda apresentavam, em média, pressão arterial sistólica de 8 mmHg maior do que os controles (p > 0,05), e os valores de pressão de pulso significativamente mais elevados. O modelo de regressão linear múltipla mostra que 93,8% da variabilidade da VOP é explicada pelas variáveis idade, pressão arterial média (PAM) e pela própria doença (R2 ajustado = 0,938). A análise logística stepwise usando como variável dependente o valor de corte de VOP estabelecido pela curva ROC (> 8,34 m/s) e, como variáveis independentes, os parâmetros com significância na análise univariada, revelou que arterite de Takayasu (OR: 4,69, IC 95% 1,31 - 16,72; p = 0,017) e PAM (OR: 1,06, IC 95% 1,00 - 1,12, p = 0,048) foram independentemente associados a maior VOP. Uma análise mais aprofundada dos parâmetros de doença revelou que os valores de VOP não foram correlacionados com velocidade de hemossedimentação, proteína C-reativa, dose cumulativa de glicocorticoides e fração de ejeção (p > 0,05). Conclusão: Nesta coorte de pacientes do sexo feminino com arterite de Takayasu, a própria doença e a pressão arterial média foram os determinantes mais fortemente associados com elevada rigidez arterial e não houve correlação dos valores de VOP com parâmetros de atividade da doença<br>Takayasu arteritis (TA) is a granulomatous vasculitis that affects the aorta and large vessels and is associated with higher cardiovascular risk. Pulse wave velocity (PWV) is a method of indirect evaluation of decreased arterial distensibility, and elevated PWV correlates with increased cardiovascular morbidity and mortality. The assessment of PWV in patients with Takayasu arteritis is complex due to many confounding factors. The aim of this study was to evaluate arterial stiffness, assessed by carotid-femoral pulse wave velocity (CF-PWV) in female patients with TA and healthy controls with comparable anthropometric and clinical variables, and the possible association with parameters of the disease. Method: Patients with TA (n = 27) were consecutively evaluated and healthy controls were selected with comparable age, blood pressure, weight and height (n = 27). Exclusion criteria were menopause, smoking, diabetes, renal insufficiency, poorly controlled hypertension, cardiac arrhythmias, obesity, inflammatory comorbidities, pregnancy and history of surgical procedures involving the aorta. Disease activity was determined by clinical and laboratory parameters. The CF-PWV measurements were obtained by the Complior System. Results: The mean CF-PWV was higher in patients with TA than in controls (9.77 ± 3.49 vs. 7.83 ± 6.1 m / s, p = 0.009). Despite the strict selection criteria, TA patients still had, on average, systolic blood pressure of 8 mmHg greater than controls (p > 0.05), and pulse pressure values significantly higher. The multiple linear regression model showed that 93.8% of the variability in PWV is explained by the variables age, mean arterial pressure (MAP) and the disease itself (adjusted R2 = 0.938). A stepwise logistic analysis using as the dependent variable the cutoff value of VOP established by the ROC curve (> 8.34 m/s) and, as independent variables, parameters with significance in the univariate analysis, revealed that Takayasu arteritis (OR: 4.69 95% CI 1.31 - 16.72, p = 0.017) and MAP (OR: 1.06, 95% CI 1.00 - 1.12, p = 0.048) were independently associated with increased PWV. Further analysis of disease parameters revealed that PWV values were not correlated with erythrocyte sedimentation rate, C-reactive protein, cumulative dose of glucocorticoids or ejection fraction (p > 0.05). Conclusion: In this cohort of female patients with Takayasu arteritis, the disease itself and mean arterial pressure were determinants most strongly associated with elevated arterial stiffness and no correlation of PWV values and parameters of disease activity was found
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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/.
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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 vascular<br>Introduction: 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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Allen, John. "Measurement and analysis of multi-site photoplethysmographic pulse waveforms in health and arterial disease." Thesis, University of Newcastle Upon Tyne, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.247830.
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Mullan, B. A. "Factors influencing endothelial function and arterial pulse wave morphology : the role of oxidative stress." Thesis, Queen's University Belfast, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.398095.
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Gradvohl, Hissa Tavares de Lima. "Amplitude de pulso ocular em pacientes com hipertensão arterial sistêmica." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/17/17150/tde-21072016-105946/.
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Objetivo: Avaliar a amplitude de pulso ocular (APO) em pacientes com hipertensão arterial sistêmica, comparando com o grupo controle, e eventuais influências da espessura central da córnea e do comprimento axial (COMPRaxial) do olho na APO. Método: Foram examinados 152 olhos de 76 pacientes com hipertensão arterial sistêmica e 136 olhos de 68 indivíduos que compuseram o grupo controle. Todas as medidas foram tomadas pelo mesmo examinador, no período das 7 às 10h da manhã, na seguinte ordem: pressão arterial sistêmica, tonometria de contorno dinâmico, COMPRaxial e paquimetria (PAQ). A análise estatística foi realizada utilizando-se o teste t para médias de dados pareados e, para as correlações, os coeficientes de Pearson ou o de Spearman. Considerou-se o nível de significância de 5%. Resultados: A APO média dos olhos direitos dos pacientes com hipertensão arterial sistêmica foi 2,10 (+/- 0.9 mmHg) e a dos olhos esquerdos foi 2,03 (+/-0,828 mmHg). A PAQ média dos olhos direitos foi 532.2 mµ (+/- 39 mµ), e a dos olhos esquerdos 532.1 mµ (+/- 36.5 mµ), não influenciando a APO. A variável COMPRaxial para o olho direito (OD) apresentou média de 23,44 mm (+/- 1.477 mm) e para o olho esquerdo (OE) foi de 23.343 em média (+/- 1,32 mm). Houve significância estatística quando estudada a influência do COMPRaxial sobre a APO, demonstrando correlação inversamente proporcional. A média da APO dos controles foi de 2,10 (+/- 0.9 mmHg) e para o OD e OE média de 2,03 (+/-0,828 mmHg). Quando comparados os valores médios da APO dos casos e controles, a diferença foi estatisticamente significante, sendo os valores dos controles maiores do que os encontrados nos pacientes com hipertensão arterial sistêmica (p <0 ,001). Constatou-se que existe diferença entre caso e controle, tanto para o OD quanto para o OE. Conclusões: O valor médio de APO foi menor nos pacientes com hipertensão arterial sistêmica do que nos controles; a APO não foi influenciada pela espessura central da córnea; e olhos com maior COMPRaxial apresentaram APO menor<br>Objective: The objectives of this study were to assess the ocular pulse amplitude (OPA) in patients with hypertension, compared with control group and to evaluate possible influences of central corneal thickness and axial length of eye in OPA. Method: We evaluated 152 eyes of 76 patients with hypertension and 136 eyes of 68 individuals who comprised the control group. All measurements were made by the same examiner in the period of 7 am and 10 am, in following order: blood pressure, dynamic contour tonometry, axial length and pachymetry. Statistical analysis was performed using the t test for paired data and averages for correlations, the Pearson correlation coefficients of Spearman. Considered the significance level of 5%. Results: The average OPA in right eyes of patients with hypertension was 2.10 (standard deviation (SD) 0.9 mmHg) and in left eyes was 2.03 (SD =0.828 mmHg). The average pachymetry of right eyes was 532.2 mµ (+/- 39 mµ); and for left eyes was 53.1 mµ ( +/-36.5 mµ). The variable diameter axial in right eye showed an average of 23.44 mm (+/- 1.477 mm); for the left eye 23,343 mm (+/- 1.32). There was statistical significance when studied the influence of the axial diameter of OPA, with inverse correlation. The average of controls OPA was presented mean 2.10 (+/- 0.9 mmHg) for the right eye and the left mean 2.03 (+/- 0.828 mmHg). When comparing the mean values of OPA in cases and controls the difference was statistically significant, the values of the controls are larger those found in patients with hypertension (p<0,001), so it was found difference between cases and controls, both for the right and left eye. Conclusions: The mean OPA was lower in patients with hypertension than in controls, the OPA was not influenced by central corneal thickness, and eyes with greater axial length showed lower OPA
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Pascoalino, Lucas Nóbilo. "Efeitos da atividade física aeróbica sobre a pressão arterial sistêmica e rigidez arterial em pacientes submetidos a transplante cardíaco." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/5/5131/tde-14012013-153710/.
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O transplante cardíaco permanece sendo o procedimento de escolha para a insuficiência cardíaca refratária, apresentando resultados favoráveis em termos da sintomatologia, qualidade de vida e sobrevida desses pacientes. A hipertensão arterial sistêmica aparece como a comorbidade de maior incidência neste grupo de pacientes, chegando a 95% após cinco anos. O efeito do exercício físico sobre a dinâmica do comportamento tensional na monitorização da pressão arterial ambulatorial durante 24 horas (MAPA-24h) e da rigidez arterial não tem sido estudado neste grupo de pacientes. Nós avaliamos os efeitos da atividade física aeróbia sobre a dinâmica do comportamento tensional na MAPA-24h, rigidez arterial e as variáveis cardiovasculares em indivíduos após um ano de transplante cardíaco. Trinta e nove pacientes de ambos os sexos, randomizados para grupo treino (GT) (n = 29; 45 ± 13 anos) ou grupo controle (GC) (n = 9; 51 ± 11 anos) realizaram, antes e após o período de 12 semanas de seguimento, exames de MAPA-24h, velocidade de onda de pulso carótido-femoral (VOP) e teste de esforço cardiopulmonar, com coletas de amostras sangüíneas para dosagem de norepinefrina (Nor) (repouso e pico). Treinamento físico aeróbio foi realizado três vezes por semana, sendo duas supervisionadas e uma não supervisionada, durante 40 minutos inicialmente com a frequência cardíaca monitorada em 80% do ponto de compensação respiratória. O GT apresentou redução significativa da pressão arterial sistólica nos períodos da média das 24 horas (de 120 ± 11 para 116 ± 14mmHg, p<0,05) e vigília (de 123 ± 11 para 118 ± 13mmHg, p<0,05). A pressão arterial diastólica apresentou redução significativa para os três períodos sendo na média das 24 horas (de 81 ± 9 para 74 ± 9mmHg, p< 0,001), vigília (de 83 ± 9 para 75 ± 10mmHg, p<0,001) e noturno ( de 77 ± 10 para 71 ± 10mmHg, p<0,001). A VOP não apresentou redução significativa após o período de seguimento para ambos os grupos; GT (de 10,0 ± 1,9 para 9,7 ±1,9m/s, p = ns) e GC (de 10,3 ± 2,2 para 10,4 ± 2,8m/s, p = ns), porém os níveis da Nor tiveram aumento significativo no pico do exercício no grupo GT (de 2386 ± 1274 para 3292 ± 1410 pg/ml p<0,01) e também em relação ao grupo GC pós seguimento (3292 ± 1419 versus 2178 ± 659 pg/ml, p<0,05). O treinamento físico aeróbio reduziu a pressão arterial sistólica/diastólica em 4,7/7,5 mmHg durante a vigília e em 3,5/5,8 mmHg durante o sono após TX, além de melhorar o condicionamento cardiorrespiratório com aumento do VO2pico, FCmáx e do tempo de exercício.<br>Cardiac transplantation remains the procedure of choice for refractory heart failure, with favorable results in terms of symptoms, quality of life and patient survival. Hypertension appears as a higher incidence of comorbidity in this group of patients, reaching 95% after five years. However, the effect of exercise training in the behavior of 24-hour ambulatory blood pressure monitoring (ABPM) and arterial stiffness has not been studied in this group of patients. We assessment the effects of aerobic physical activity in the behavior of ABPM, arterial stiffness and cardiovascular variables in patients being heart transplanted for a year or more. Thirty-nine patients of both genders were evaluated, then randomized to either training group (TG) (n = 29, 45 ± 13 years) or control group (CG) (n = 9, 51 ± 11 years) and reevaluated after 12 weeks of follow-up. Pre and post evaluations combined examinations of ABPM, carotidfemoral pulse wave velocity (PWV) and graded exercise test, with collections of blood samples for measurement of norepinephrine (Nor) (rest and peak). Aerobic exercise was performed in the TG three times-a-week, two supervised and one unsupervised for 40 minutes initially at an intensity of 80% of heart rate achieved at the respiratory compensation point. The TG showed a significant reduction in systolic blood pressure during average of 24 hours (from 120 ± 11 to 116 ± 14mmHg, p < 0.05) and diurnal cycle (from 123 ± 11 to 118 ± 13mmHg, p<0.05). Diastolic blood pressure decreased significantly for the three periods, the average of 24 hours (from 81 ± 9 to 74 ± 9mmHg, p<0.001), diurnal cycle (from 83 ± 9 to 75 ± 10mmHg, p < 0.001) and nighttime (from 77 ± 10 to 71 ± 10mmHg, p < 0.001). The PWV showed no significant reduction after the followup period for both groups; TG ( from 10.0 ± 1.9 to 9.7 ± 1.9m/s, p = ns) and CG (from10.3 ± 2.2 to 10.4 ± 2.8m/s, p = ns) and the levels of the Nor had a significantly higher peak exercise in TG (from 2386 ± 1274 to 3292 ± 1410 pg/ml p <0.01) and also in relation to the control group after follow-up (3292 ± 1419 versus 2178 ± 659 pg / ml, p <0.05). The exercise training reduced both systolic and diastolic blood pressure in 4.7 and in 7.5 mmHg during daytime, respectively. Reduction also happened during nighttime in 3.5 and in 5.8 mmHg for these variables, respectively. Exercise training improved VO2peak, HRmax and time of exercise (cardiorespiratory fitness) after follow-up, as well.
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Menard, Alain A. "A microprocessor system for the characterisation of arterial pulse waves obtained from microwave impedance measurements." Thesis, University of Ottawa (Canada), 1985. http://hdl.handle.net/10393/4735.
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Júnior, Raimundo Jenner Paraiso Pessôa. "Impacto do gênero na rigidez arterial, remodelamento cardíaco e pressão arterial em pacientes hipertensos com e sem apneia obstrutiva do sono." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/5/5131/tde-03022016-110209/.
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Introdução: A apneia obstrutiva do sono (AOS) é uma condição clínica comum associada com o aumento do risco cardiovascular. No entanto, a maioria dos estudos envolvendo AOS e desfechos cardiovasculares recrutaram de forma preponderante os homens. Em pacientes hipertensos, a AOS pode contribuir para a lesão de órgãos-alvo e alterações no descenso noturno em homens. O impacto da AOS nas mulheres hipertensas é pouco estudado. O objetivo deste estudo é estudar o impacto da AOS na rigidez arterial da aorta (avaliada pela velocidade da onda de pulso, VOP, carótida-femoral), disfunção diastólica e alterações do descenso noturno da pressão arterial em ambos os gêneros. Fazemos a hipótese de que a AOS está associada com alterações na rigidez arterial, disfunção diastólica e comportamento da pressão arterial independente do gênero. Métodos: Recrutamos de forma consecutiva pacientes hipertensos estágio 2 do ambulatório de Hipertensão do Instituto do Coração. Padronizamos a medicação anti-hipertensiva (hidroclorotiazida 25mg ao dia e enalapril 20mg 2x ao dia ou losartan 50mg 2x ao dia em caso de intolerância ao enalapril) por 1 mês. A adesão do tratamento aconteceu por meio da contagem de pílulas. Foram realizadas avaliações da monitorização ambulatorial da pressão arterial (MAPA), VOP, ecocardiograma transtorácico, exames laboratoriais e a Polissonografia Noturna. A AOS foi diagnosticada por um índice de apneia e hipopneia >= 15 eventos por hora de sono. Resultados: Foram inicialmente recrutados 125 participantes e após as exclusões, avaliamos 95 pacientes hipertensos (56% mulheres). A frequência da AOS foi de 66,7% em homens e 45,3% em mulheres (p=0,02). Em relação às mulheres sem AOS, mulheres com AOS eram mais velhas, tinham maior índice de massa corpórea e apresentaram maiores circunferências cervical e abdominal. Os homens com e sem a AOS foram semelhantes em várias características, exceto por uma circunferência abdominal maior no grupo com AOS. Comparado aos pacientes sem AOS, a VOP foi estatisticamente maior nos homens portadores de AOS (11,1±2,2 vs. 12,7±2,4m/s, respectivamente; p=0,04), assim como nas mulheres (11,8±2,4 vs. 13,2±2,2m/s, respectivamente; p=0,03). Em relação à disfunção diastólica, apenas as mulheres com AOS mostraram maior porcentagem dessa alteração ecocardiográfica (46,1 vs. 81,8%, respectivamente; p=0,007). Foi visto nos resultados da MAPA, que homens com AOS apresentaram menor frequência do descenso noturno sistólico (46,4 vs. 14,3%, respectivamente; p=0,04) e as mulheres, uma tendência (65,2 vs. 41,4%; p=0,07). O resultado da regressão linear mostrou que a presença de AOS promove aumento independente nos valores da VOP. O resultado da regressão logística evidenciou que a presença da AOS não foi associada com a disfunção diastólica, mas foi com a ausência do descenso noturno do componente sistólico da pressão arterial. Conclusões: Em pacientes hipertensos, a presença da AOS foi associada com um aumento na rigidez arterial independente do sexo, assim como a ausência do descenso noturno do componente sistólico da pressão arterial. Estes dados sugerem que mulheres hipertensas também estão expostas às consequências vasculares da AOS<br>Introduction: Obstructive sleep apnea (OSA) is a common condition associated with increased cardiovascular risk. However, most of studies that addressed OSA and its cardiovascular consequences enrolled mainly men. In hypertensive patients, OSA may contribute to increased target organ damage and alterations in the blood pressure dipping in males. However, the impact of OSA in hypertensive females is not well established. In this study, we compared the impact of OSA on arterial stiffness of the aorta (evaluated by carotid-femoral pulse wave velocity, PWV), as well as diastolic dysfunction and blood pressure dipping in men and women with hypertension. We made the hypothesis that OSA is associated with higher arterial stiffness, higher frequency of diastolic dysfunction and impaired blood pressure behavior regardless of gender. Methods: We recruited consecutives stage 2 hypertensive patients from the outpatient clinic at the Heart Institute. We performed a 30-day standardized anti-hypertensive treatment with hydrochlorothiazide 25mg per day plus enalapril 20mg BID or losartan 50mg BID (if enalapril intolerance). Adherence to treatment was confirmed through pill counting. After that, all volunteers were submitted to clinical evaluation, carotid-femoral PWV, 24-hour ambulatory blood pressure monitoring, transthoracic echocardiogram, and polysomnography. OSA was defined by an apnea-hypopnea index >= 15 events per hour. Results: We initially recruited 125 participants and after exclusions ninety-five patients were studied (56% women). OSA was present in 52 patients (men: 66.7%; women: 45.3%; p=0.02). In comparison to women without OSA, women with OSA were older, had higher body mass index and higher neck and abdominal circumferences. In men, there were no differences between OSA and no-OSA groups, except for higher values of abdominal circumference in OSA patients. Compared to no-OSA patients, PWV values were higher in the OSA group among both males (11.1±2.2 vs. 12.7±2.4m/s, respectively; p=0.04) and females (11.8±2.4 vs. 13.2±2.2m/s, respectively; p=0.03). The impact of OSA on diastolic dysfunction was significant only in females (46.1 vs. 81.8%, respectively; p=0.007). Regarding ambulatory blood pressure monitoring data, the frequency of systolic blood pressure dipping was significantly lower in men with OSA (46.4 vs. 14.3%, respectively; p=0.04) and marginal but non-significant in women (65.2 vs. 41.4%; p=0.07). Linear regression analysis showed that the presence of OSA was independently associated with higher PWV. In the logistic regression analysis, OSA was not associated with diastolic dysfunction but independently associated with nondipping systolic blood pressure. Conclusion: In patients with hypertension, OSA has significant associated with higher arterial stiffness and nondipping systolic blood pressure regardless of gender. These data suggest that hypertensive women are also exposed to the vascular and hemodynamic consequences of OSA
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Dastmalchi, Azadeh. "Beat-to-Beat Estimation of Blood Pressure by Artificial Neural Network." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/31962.
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High blood pressure is a major public health issue. However, there are many physical and non-physical factors that affect the measurement of blood pressure (BP) over very short time spans. Therefore, it is very difficult to write a mathematical equation which includes all relevant factors needed to estimate accurate BP values. As a result, a possible solution to overcome these limitations is the use of an artificial neural network (ANN). The aim of this research is to design and implement a new ANN approach, which correlates the arterial pulse waveform shape to BP values, for estimation of BP in a single heartbeat. To test the feasibility of this approach, a pilot study was performed on an arterial pulse waveform dataset obtained from 11 patients with normal BP and 11 patients with hypertension. It was found that the proposed method can accurately estimate BP in single heartbeats and satisfy the requirements of the ANSI/AAMI standard for non-invasive measurement of BP.
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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.
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Eberth, John Francis. "Arterial biomechanics and the influences of pulsatility on growth and remodeling." [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-3117.
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Sanz, Miralles Elena C. "Pulse wave imaging as an indicator of arterial stiffness in patients affected with periodontitis = Imagen de onda de pulso como indicador de la rigidez arterial en el paciente periodontal = Imatge de l’ona del pols com indicador de rigidesa arterial en el pacient periodontal." Doctoral thesis, Universitat de Barcelona, 2017. http://hdl.handle.net/10803/406351.
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In this thesis, the relationship between periodontitis and arterial stiffness was assessed by a new technique known as Pulse Wave Imaging (PWI). PWI is a non-invasive ultrasound-based technique developed by members of our team, and is intended to overcome some limitations of classic methods for assessing elasticity. PWI can be used to determine Pulse Wave Velocity (PWV) and assess homogeneity in the transmission of the wave (R2). In addition, a feasibility study was conducted to determine Pulse Pressure (PP) at a central artery through PWI.
A cross-sectional study including a sample of 80 volunteers was designed excluding participants with a history of cardiovascular disease, apart from hypertension. 40 subjects presented with moderate to severe periodontitis, defined as a minimum of two teeth per quadrant with probing depths (PD)>5mm, concomitant clinical attachment loss (CAL)>3mm and bleeding on probing (BoP) in more than 30% of the sites. The control group was comprised of gender- and age-matched (within a 5 year interval) periodontally healthy subjects with absence of PD>4mm and interproximal CAL>2mm. All patients received a full periodontal exam and the elasticity of right and left carotid arteries was assessed to determine the outcome variables PWV and R2. As PWI is a new technique, two thresholds (A and B) were used to analyze the results. Threshold A was generic while Threshold B was individualized. To explore differences within the groups, the PWV and R2 results from the paired samples were compared using the Wilcoxon Signed Rank Test. Univariate and multivariate analyses were carried out to assess the association between PWV/R2 and other explicative variables.
For the PP evaluation, a subsample of patients in whom the aorta was easily visible with ultrasounds was chosen. The patients were classified by their brachial blood pressure as normotensive, pre- or hypertensive. PP was then calculated in three locations of the arterial tree – brachial, radial and aortic arteries. The PP results were analyzed through the two-way ANOVA and the Bonferroni correction.
The application of Thresholds A and B resulted in 30 and 33 control-patient pairs, respectively. Results from Threshold A did not reveal statistically significant differences between the groups in regards to PWV (median of 2.37m/sec for periodontitis patients vs. 2.64m/sec in controls, p=0.74) or R2 (0.74 vs. 0.71, p=0.81). The univariate analysis revealed negative non-significant associations between the outcome variable R2 and the explicative variables: presence of periodontitis, variables related to periodontitis, age, and systolic/diastolic blood pressures. The multiple regression analysis revealed a significant association between R2 and gender (p=0.04). The results from Threshold B differed, revealing that patients with periodontitis presented significantly lower uniformity in wave propagation (R2) than controls (p=0.01), while PWV results were not statistically different between the two groups. Univariate analysis showed a significant negative association between R2 and periodontitis, its associated variables, and smoking. Periodontitis remained statistically associated with R2 in the multivariable analysis. When studying the PP results, significantly higher values were observed in the aortas of hypertensive patients compared to the values obtained in the radial and brachial arteries, regardless of the patients’ blood pressure status.
In summary, a lower degree of uniformity was observed in the transmission of the pulse wave in the carotid artery in a sample of periodontal patients with no history of cardiovascular disease. This suggests an association between periodontitis and arterial stiffness and supports the body of evidence indicating an association between periodontitis and atherosclerosis. Notably, the results from applying Threshold A and B were quite different, emphasizing the importance of using personalized thresholds. The PP analysis concluded that it is feasible to use non-invasive methods to determine PP in high-caliber central arteries such as the aorta.<br>Se investigó la relación entre el estado periodontal y la rigidez arterial mediante Imagen de Onda de Pulso (PWI). PWI es una técnica no invasiva basada en el uso de ultrasonidos, la cual ha sido recientemente desarrollada por miembros de nuestro equipo y que pretende superar algunas de las limitaciones de las técnicas clásicamente utilizadas para valorar la elasticidad arterial. En este trabajo, PWI se utilizó para calcular la velocidad de la onda del pulso (PWV) y valorar la homogeneidad de transmisión de la misma (R2). A su vez, se analizó la factibilidad del cálculo de la Presión del Pulso (PP) en una arteria central mediante el uso de la misma técnica.
Se analizó transversalmente una muestra de 80 individuos, pareada respecto a género y edad (±5 años). Cuarenta pacientes presentaban periodontitis moderada-severa, y el resto fueron clasificados como periodontalmente sanos. Pacientes con antecedentes de enfermedad cardiovascular (excepto hipertensión) fueron excluidos. Los resultados obtenidos al determinar la PWI en la carótida (PWV y R2) fueron analizados mediante el uso de dos umbrales diferentes, uno genérico y otro personalizado, mientras que la PP fue determinada en las arterias aorta, braquial y radial mediante el uso de tres métodos distintos.
Los resultados muestran menor uniformidad en la propagación de la onda (R2) en los pacientes periodontales tras aplicar el umbral personalizado (p=.01). El análisis univariable reveló una asociación significativa negativa entre R2 y periodontitis, sus variables asociadas y tabaco. Esta asociación se mantuvo en el análisis multivariable entre R2 y periodontitis. Por otro lado, no se observaron diferencias estadísticamente significativas para las variables PWV y R2 al aplicar el umbral genérico o respecto a PWV tras aplicar el umbral individualizado. En referencia al análisis de la PP, se confirma la factibilidad en su obtención en arterias centrales de pacientes hipertensos.
En conclusión, se encontró una asociación entre periodontitis y una alteración funcional de las arterias, resultando en una disminución de su elasticidad. Respecto al análisis de datos realizado, cabe destacar el impacto en los resultados al considerar umbrales genéricos vs. personalizados. PWI se perfila como un método innovador en el análisis de la elasticidad arterial en pacientes con factores de riesgo arteriosclerótico y sin historia de eventos CV mayores.
28
Schoevers, Jacobus Engelbertus. "Low blood oxygen saturation quantification in human arterial and venous circulation." Thesis, Stellenbosch : Stellenbosch University, 2008. http://hdl.handle.net/10019.1/21460.
Full textAbstract:
Thesis (MScIng)--Stellenbosch University, 2008.<br>ENGLISH ABSTRACT: Conventional pulse oximetry has limited accuracy in measuring blood oxygen saturation
in low saturation and perfusion scenarios. This limits the application of
pulse oximetry in patients su ering from peripheral vascular a ictions.
A novel pulse oximetry system is presented in this study which proposes solutions
to these low saturation and perfusion issues. The presented system was
designed to overcome the low perfusion issues by inducing an arti cial pulse in the
detected photoplethysmograph. A novel arterio-venous hypothesis was formulated
to extract arterial and venous saturation data from this arti cial photoplethysmograph
using arterial-to-venous compliance ratios. Sensor wavelengths were selected
to provide high and low saturation accuracy, followed by an in vitro sensor calibration
procedure. System performance was validated by means of in vivo human
studies.
In vivo results indicate good accuracy for high saturation, with limited accuracy
in low saturation scenarios. The arterio-venous hypothesis was validated, indicating
that venous saturation information can be extracted from the arti cial PPG.
Although inconclusive, results indicate that the proposed system might be able
to accurately monitor arterial and venous saturation in severe hypoperfusion scenarios
with recommended hardware and calibration modi cations. It is recommended
that further studies into the presented system's performance are conducted.<br>AFRIKAANSE OPSOMMING: Konvensionele 'pulse oximetry' sisteme het beperkte akkuraatheid tydens die meting
van bloed suurstof saturasie in lae saturasie en perfusie gevalle. Dit beperk die
bruikbaarheid van 'pulse oximetry' in pasiënte wat ly aan perifere vaskulêre siektes.
'n Nuwe 'pulse oximetry' sisteem, wat oplossings vir hierdie lae saturasie en
perfusie beperkings voorstel, word in hierdie studie aangebied. Die voorgestelde
sisteem is ontwerp om die lae perfusie beperkings te oorkom deur 'n kunsmatige
polsslag in die 'photoplethysmograph' te induseer. 'n Nuwe arterio-veneuse hipotese
is geformuleer om arteriële en veneuse saturasie inligting uit hierdie kunsmatige
polsslag te onttrek deur middel van 'n arteriële-teenoor-veneuse styfheids verhouding.
Die gol engtes wat gebruik is in die sensors, is spesi ek gekies om hoë en
lae saturasie akkuraatheid te verskaf. 'n In vitro kalibrasie prosedure is gevolg om
die sensors vir hoë en lae saturasie te kalibreer, waarna die werkverrigting van die
sisteem getoets is deur middel van 'n in vivo validasie prosedure.
Die in vivo resultate toon goeie akkuraatheid vir hoë saturasie, met beperkte
akkuraatheid vir lae saturasie. Die arterio-veneuse hipotese is gevalideer, wat aandui
dat veneuse saturasie wel uit die kunsmatige 'photoplethysmograph' onttrek
kan word.
Alhoewel die resultate wat in hierdie studie aangebied word nie omvattend of
beslissend is nie, dui dit egter aan dat die voorgestelde sisteem dalk in staat kan
wees om arteriële en veneuse saturasie in uiters lae perfusie gevalle te meet. Verbeteringe
sal egter aan die sisteem aangebring moet word in terme van hardeware
en kalibrasie, om 'n meer gestandardiseerde metings metode te verseker. Verdere
navorsing oor die werkverrigting van die voorgestelde sisteem word ook voorgestel.
29
Elam, Charles R. IV. "Predicting Arterial Oxygen Desaturation Events Via Patient Journal and Pulse Oximetry Data in Postoperative Ambulatory Surgery Patients." VCU Scholars Compass, 2018. https://scholarscompass.vcu.edu/etd/5649.
Full textAbstract:
Associations between patient and procedural factors on the nature and quality of the immediate in-home recovery from anesthesia following ambulatory orthopedic surgery are unknown. Further, there is a paucity of outcomes research quantitatively categorizing in-home
patient recovery and safety following discharge from same-day orthopedic procedures. Tools are available, however, to shed light on outcomes in this population, and integration of such available measures is critical.
Ambulatory orthopedic surgery is a burgeoning specialty, with growth expected over the foreseeable future. The expected increased patient caseload subsequent to implementation of the Affordable Care Act and aging Baby Boom generation suggests greater morbidity and mortality is on the horizon unless aggressive measures are taken at mitigating risk. Similarly, as the obesity epidemic expands, obesity-related comorbid conditions including obstructive sleep apnea (OSA) are likely to grow.
The purpose of this research was to explore the relationship between ambulatory orthopedic patient-reported activities (quality of life metrics) and diagnostic factors (physical and perioperative care data) in the immediate postoperative period that are predictive of arterial oxygen desaturation. Data was obtained using a novel patient journal exploring sleep, pain, nausea, tobacco use, alcohol use, and appetite in conjunction with a valid and reliable portable, wrist-worn pulse oximeter. Additional assessment data was taken from the preanesthetic assessment. All participants were scored according to the STOP-Bang questionnaire, an accepted survey of OSA risk.
Patients were recruited from a busy metropolitan ambulatory surgery center in Richmond, Virginia that sees approximately 500 cases monthly, and a 309-bed tertiary care hospital in West Burlington, Iowa. The target sample included 52 individual patients with data collected over the first two post-operative nights following discharge. Two patients were excluded.
Negative binomial regression, log10 transformation, and least-squares regression examined the relationships the STOP-Bang questionnaire, quality of life data, and physical perioperative data had on postoperative desaturation events. Results suggested the STOP-Bang score predicted desaturation events and that age and BMI were significant individual predictors. Opiate pain medication treatment, a happy mood, and home CPAP use were associated with decreased events.
This study provided a unique perspective in patient safety research, relating human behaviors and experiences with postoperative oxygen desaturation. Future research projects aligned with postoperative monitoring, pulse oximetry, patient safety, and obstructive sleep apnea are potential following the findings of this study.
30
Prokopowitsch, Aleksander Snioka. "Avaliação não-invasiva das propriedades da parede arterial em pacientes portadoras de lúpus eritematoso sistêmico." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/5/5145/tde-01062007-114759/.
Full textAbstract:
OBJETIVO: Avaliar a rigidez e distensibilidade arterial em mulheres não-menopausadas portadoras de lúpus eritematoso sistêmico (LES), bem como a influência da atividade de doença sobre esses parâmetros. MÉTODOS: 37 pacientes lúpicas do sexo feminino com idade menor ou igual a 40 anos e com até 10 anos de doença foram selecionadas para o estudo. Os critérios de exclusão utilizados foram: tabagismo atual ou prévio, hipertensão arterial sistêmica, diabetes mellitus, obesidade, insuficiência renal crônica, síndrome antifosfolípide secundária e gravidez ou menopausa no momento do estudo. As pacientes foram divididas em portadoras de doença ativa (SLEDAI maior ou igual a 4) e não-ativa (SLEDAI menor que 4) e comparadas a 25 mulheres saudáveis. Todos os indivíduos participantes foram submetidos à avaliação de rigidez e distensibilidade arterial por mensuração da velocidade de onda de pulso (VOP) carótido-femoral e echo-tracking da artéria carótida comum direita. RESULTADOS: Houve diferença significativa em relação à VOP entre os grupos estudados (p=0.01). Pacientes com LES em atividade apresentaram menor VOP que pacientes fora de atividade (6.89 ± 1.00 vs. 7.79 ± 1.10 m/s, p<0.05) e controles (6.89 ± 1.00 vs. 8.14 ± 1.07 m/s, p<0.05). Além disso, houve correlação negativa significativa entre VOP e SLEDAI (r=-0.354, p=0.03). Todos os parâmetros obtidos através do echo-tracking foram semelhantes entre os grupos: espessura íntima-média (EIM) (p=0.50), diâmetro diastólico (p=0.34), coeficiente de distensibilidade (p=0.98), coeficiente de complacência (p=0.74) e módulo elástico (p=0.87). A EIM correlacionou-se significativa e positivamente com a idade (r=0.328, p=0.04) e negativamente com os níveis de HDL-colesterol (r=-0.366, p=0.03) e apolipoproteína A1 (r=-0.407, p=0.01). Foi observada tendência de correlação positiva entre EIM e tempo de doença (r=0.306, p=0.06). CONCLUSÃO: Este estudo demonstra que a atividade lúpica é responsável por alterações na parede arterial compatíveis com processo aterosclerótico precoce, uma vez que a redução de rigidez arterial observada na doença ativa pode ser secundária a maior infiltração inflamatória e formação de células espumosas.<br>OBJECTIVE: To evaluate arterial stiffness and distensibility in pre-menopausal female systemic lupus erythematosus (SLE) patients and assess the influence of disease activity on these parameters. METHODS: Thirty-seven female SLE patients aged less than 40 years old and with less than 10 years of disease duration were selected. Exclusion criteria were smoking, arterial hypertension, diabetes mellitus, obesity, chronic renal failure, secondary antiphospholipid syndrome, and pregnancy or menopause at the time of the study. Patients were divided into active (SLEDAI>4) or inactive (SLEDAI<4) disease, and compared to twenty-five healthy female controls. All subjects underwent arterial stiffness and distensibility evaluation by carotid-femoral pulse wave velocity (PWV) and common carotid echo-tracking. RESULTS: PWV was significantly different among the studied groups (p=0.01). Active SLE patients had lower PWV levels compared to inactive SLE patients (6.89 ± 1.00 vs. 7.79 ± 1.10 m/s, p<0.05) and also to controls (6.89 ± 1.00 vs. 8.14 ± 1.07 m/s, p<0.05). Moreover, there was a significant negative correlation between PWV and SLEDAI (r=-0.354, p=0.03). All carotid echo-tracking parameters were similar among groups (p>0.05): intima-media thickness (IMT) (p=0.50), diastolic diameter (p=0.34), distensibility coefficient (p=0.98), compliance coefficient (p=0.74), and elastic incremental modulus (p=0.87). IMT had a positive significant correlation with age (r=0.328, p=0.04) and a negative significant correlation with HDL (r=-0.366, p=0.03) and apolipoprotein A1 (r=-0.407, p=0.01). A trend of positive correlation between IMT and disease duration (r=0.306, p=0.06) was observed. CONCLUSION: This study demonstrates that SLE activity is responsible for alterations in arterial walls compatible with early atherosclerotic process, since the reduced arterial stiffness observed in active disease may be secondary to a greater inflammatory infiltration and foam cell formation.
31
Marwah, Kunal. "Development of Motion Artifact Rejection Algorithms for Ambulatory Heart Rate and Arterial Oxygen Measurement By A Wearable Pulse Oximeter." Digital WPI, 2012. https://digitalcommons.wpi.edu/etd-theses/1320.
Full textAbstract:
Over the past decade, there has been an increasing interest in the real-time monitoring of ambulatory vital signs such as heart rate (HR) and arterial blood oxygen saturation (SpO2) using wearable medical sensors during field operations. These measurements can convey valuable information regarding the state of health and allow first responders and front-line medics to better monitor and prioritize medical intervention of military combatants, firefighters, miners and mountaineers in case of medical emergencies. However, the primary challenge encountered when using these sensors in a non-clinical environment has been the presence of persistent motion artifacts (MA) embedded in the acquired physiological signal. These artifacts are caused by the random displacement of the sensor from the skin and lead to erroneous output readings. Several signal processing techniques, such as time and frequency domain segmentation, signal reconstruction techniques and adaptive noise cancellation (ANC), have been previously developed in an offline environment to address MA in photoplethysmography (PPG) with varying degrees of success. However, the performance of these algorithms in a spasmodic noise environment usually associated with basic day to day ambulatory activities has still not been fully investigated. Therefore, the focus of this research has been to develop novel MA algorithms to combat the effects of these artifacts. The specific aim of this thesis was to design two novel motion artifact (MA) algorithms using a combination of higher order statistical tools namely Kurtosis (K) for classifying 10 s PPG data segments, as either ‘clean’ or ‘corrupt’ and then extracting the aforementioned vital parameters. To overcome the effects of MA, the first algorithm (termed ‘MNA’) processes these ‘corrupt’ PPG data segments by identifying abnormal amplitudes changes. The second algorithm (termed ‘MNAC’), filters these ‘corrupt’ data segments using a 16th order normalized least mean square (NLMS) ANC filter and then extracts HR and SpO2.
32
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.
Full text
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Pereira, Edison Nunes. "AVALIAÇÃO DOS PARÂMETROS DE MEDIDA CENTRAL DA PRESSÃO ARTERIAL DE PARTICIPANTES DA CAMINHADA ECOLÓGICA DE GOIÁS." Pontifícia Universidade Católica de Goiás, 2015. http://localhost:8080/tede/handle/tede/3151.
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Previous issue date: 2015-08-11<br>In Goiás, the Ecological walk takes place annually and is an unique event
for its distance (310km) and dynamics of performance (average of 62km-day for 5
days, average speed 7.6Km-h). Although the beneficial effects of moderate exercise
are well known, the effects of intense exercise with long duration, as the Ecological
walk, have not been well studied. This study aimed to verify the effects of prolonged
exercise in central blood pressure and the correlation of these parameters with age.
A total of 25 men were included in the study. The central blood pressure was
measure datbaseline (A0), on the 2nd (A2), 3rd (A3) and 4th (A4) days of walk after the
daily stop for night rest. The following parameters were measured: peripheral and
central systolic and diastolic blood pressure, peripheral and central pulse pressure,
pulse pressure amplified, 75% augmentation index, pulse wave velocity and vascular
resistance. An oscillometric device from Mobil The Graphi® (IEM Stolber, Germany)
was used. To compare the parameters between the daily measurements we used
ANOVA for repeated measures followed by Bonferrroni post hoc and Pearson test for
correlation. We considered significant p<0.05. We assessed 25 athletes with mean
age 45.3±9.1.Central systolic blood pressure, reduced from A0 (113.8±2.1mmHg) to
A3 (105.7±1.6mmHg) (p=0.035) and increased from A3 (105.7±1.6mmHg) to A4
(111.5±1.6mmHg) (p=0.006). The central diastolic blood pressure reduced from A0
(80.3±1.9mmHg) to A3 (74.3±1.5mmHg) (p=0.018)and A2 (78.6±1) to A3
(74.3±1.5mmHg) (p=0.036) and increased from A3 (74.3±1.5mmHg) for A4
(78.6±1.7mmHg) (p=0.014). The peripheral systemic blood pressure decreased from
A0 (127.9±2.6 mmHg) to A2 (115.6±1.9mmHg) (p=0.002); to A3 (115.6±1.7mmHg)
(p=0.003) and A4 (118.6±1.5mmHg) (p=0.007). The peripheral diastolic blood
pressure reduced from A0 (78.7±1.9mmHg); from A3 (73.0±1.4mmHg) (p=0.018); A2
(77.4±1.1mmHg) to A3 (73.00±1.4mmHg) (p=0.040); and increased from A3
(73.0±1.4mmHg) to A4 (77.4±1.6mmHg) (p=0.010). The variables correlated with age
were the central systemic blood pressure (A0), Peripheral pulse pressure (A3) and
pulse wave velocity. Blood pressure decreased in the early days of walking, returning
close to baseline at the end of the competition. Pulse wave velocity was strongly
correlated with age.<br>Em Goiás, a caminhada Ecológica ocorre anualmente e é um evento
único por sua distância (310 km) e dinâmica de realização (média de 62km-dia em 5
dias, média de 7,6 km-h). Apesar de os efeitos benéficos do exercício moderado
serem bem conhecidos, os resultados de exercícios intensos e de longa duração,
como a Caminhada Ecológica, ainda não foram muito estudados. O presente estudo
teve o objetivo de verificar os efeitos do exercício físico prolongado nos parâmetros
da medida central da pressão arterial e correlacionar esses parâmetros com a idade.
Participaram do estudo 25 homens. Foi efetuada a medida central da pressão
arterial para avaliar a participação (A0), nos 2º (A2), 3º (A3) e 4º (A4) dias de
caminhada, após a parada diária para descanso noturno. Com essa medida foram
obtidos os seguintes parâmetros: pressão arterial sistólica e diastólica periférica e
central, pressão de pulso periférica e central, pressão de pulso amplificada,
augmentation índex 75%, velocidade de onda de pulso e resistência vascular. Foi
utilizado o dispositivo oscilométrico Mobil O Graphi® (IEM, Stolber, Alemanha). Para
a comparação dos parâmetros entre os dias avaliados, foi usada a ANOVA para
medidas repetidas, seguida de post hoc de Bonferrroni e para a correlação foi
aplicado o teste de Pearson. Considerou-se como significativo p<0,05. Foram
considerados 25 atletas com idade média de 45,3±9,1 anos. A medida central da
pressão arterial sistólica reduziu de A0 (113,8±2,1mmHg) para A3 (105,7±1,6mmHg)
(p=0,035) e aumentou de A3 (105,7±1,6mmHg) para A4 (111,5±1,6mmHg)
(p=0,006). A medida central da pressão arterial diastólica diminuiu de A0 (80,3±1,9
mmHg) para A3 (74,2±1,0mmHg)(p=0,018) e A2 (78,2±1,9) para A3
(74,3±1,5mmHg) (p=0,036) e aumentou da A3 (74,3±1,5mmHg) para A4
(78,6±1,7mmHg) (p=0,014). A medida da pressão arterial sistólica periférica
apresentou redução de A0 (127,9±2,6mmHg) para A2 (115,6±1,9mmHg) (p=0,002)
para A3 (115,6±1,7mmHg) (p=0,003) e para A4 (118,6±1,5mmHg) (p=0,007). A
medida periférica da pressão arterial diastólica reduziu de A0 (78,7±1,9mmHg) para
A3 (73,0±1,4mmHg) (p=0,018); de A2 (77,4±1,1mmHg) para A3 (73,00±1,4mmHg)
(p=0,040) e aumentou de A3 (73,0±1,4mmHg) para A4 (77,4±1,6mmHg) (p=0,010).
As variáveis que apresentaram correlação com a idade foram a pressão arterial
sistólica central (A0), a pressão de pulso periférica (A3) e a velocidade de onda de
pulso. A pressão arterial teve queda nos primeiros dias de caminhada, retornando
próxima aos valores basais no final do percurso. A velocidade de onda de pulso
correlacionou-se fortemente com a idade.
34
Mendes, Alessandra Beatriz Balduino. "Avaliação da rigidez arterial e pressão aórtica central em pacientes hipertensos resistentes." Faculdade de Medicina de São José do Rio Preto, 2015. http://hdl.handle.net/tede/268.
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Previous issue date: 2015-09-24<br>Background: Hypertension Resistant (RH) is defined as office blood pressure (BP) ≥140 / 90 mmHg in patients using at least three antihypertensive classes at optimal doses, including a diuretic. Arterial stiffness is a major manifestation of RH, a determining fator, for increasing central pressure and pulse pressure. Arterial stiffness can be measured by three parameters: the central arterial pressure (CAP), augmentation index (AIx) and pulse wave velocity (PWV). These parameters can be estimated by simple methods, non-invasive and with high sensitivity, such as tonometry or 24-hour ambulatory blood pressure monitoring (ABPM). Objectives: To study and compare the anthropometric, biochemical profile and central hemodynamic values (CAP, AIx and PWV) by 24-hour ABPM in patients resistant hypertension (RH), controlled hypertensive (CH) and normotensive (NT). Methodology: We selected 59 patients with resistant hypertension, 62 controlled hypertensive and 60 normotensive, all submitted to ABPM. The level of significance was accepted for P-value <0.05. Results: Individuals CH and RH group presented higher mean age and higher body mass index (60.4; 60.2 years and 29.6; 29.7 kg/m2, respectively) compared to the NT group (53.2 years and 26.2 kg/m2) (P <0.05). RH showed higher levels of creatinine and decreased renal function (1.1 mg/dL and 67.3mL/min/m2) compared to CH (0.9 mg/dL and 79.3mL/min/m2, P <0.05) and NT (0.8 mg/dl and 85.3mL/min/m 2; P <0.05). Glucose and uric acid were higher and HDL-C lower in the RH group compared to CH and NT, but without statistical significance. Systolic blood pressure (SBP) and diastolic pressure (DBP) of office were significantly higher in the RH group (137.1/80.7mmHg) compared to CH (124.3/74.0mmHg) and NT (117.5/74.3mmHg). SBP and DBP in the 24-hour ABPM in daytime and night were higher in RH (129.4/78.9, 130/80 and 128.3/76.9mmHg, respectively) compared to CH (119.4/72.7; 121.3/75.0 and 115.7/68.3mmHg, respectively) and NT (114.8/71.8, 117.8/74.8 and 109.3/66.4mmHg, respectively). Heart rate (HR) and pulse pressure (PP) were significantly higher in RH (72.4bpm/min and 52.2mmHg, respectively) than in groups CH (67.5bpm/min and 47.2mmHg, respectively) and NT (67.3bpm/min and 42.9mmHg, respectively) during the sleep period. RH showed less nocturnal than CH and NT (P <0.05). SBP and DBP in the 24-hour ABPM in daytime and night were significantly higher in RH (119.2, 118.8 and 119.8mmHg, respectively) compared to CH (110.4, 111.5 and 109mmHg, respectively) and NT (107.2; 109.2 and 104.2mmHg, respectively). PWV was higher in RH compared to CH and NT diring the three periods assessed, although there was no statistical significance. The AIx values did not differ among the three groups in all periods. In RH, age and PWV were significantly associated to the CAP. There was a positive correlation between central SBP and PP and between central SBP and PWV in the RH group. Conclusion: The patients with resistant hypertension presented CAP_ higher level than the ones with controlled hypertensive and normotensive; this clearly demonstrates a greater arterial stiffness and a growing cardiovascular risk.<br>Introdução: A Hipertensão Arterial Resistente (HAR) é definida por pressão arterial (PA) de consultório ≥140/90 mmHg, em paciente usando, pelo menos, três classes de anti-hipertensivos em dosagens otimizadas, incluindo um diurético. A rigidez arterial é uma das principais manifestações da HAR e é determinante para o aumento da pressão arterial central (PAC) e de pulso (PP). A rigidez arterial pode ser avaliada por três parâmetros: pressão arterial central (PAC), augmentation index (AIx) e velocidade de onda de pulso (VOP). Esses parâmetros podem ser estimados por métodos simples, não invasivos e com boa sensibilidade, tais como, a tonometria de aplanação ou a monitorização ambulatorial da pressão arterial (MAPA) de 24 horas. Objetivos: Estudar e comparar o perfil antropométrico, bioquímico e os valores de hemodinâmica central (PAC, AIx e VOP) por meio da MAPA 24 horas em hipertensos resistentes (HR), hipertensos controlados (HC) e normotensos (NT). Metodologia: Foram selecionados 59 pacientes hipertensos resistentes, 62 hipertensos controlados e 60 normotensos; todos submetidos à MAPA. O nível de significância admitido foi para valor-P<0,05. Resultados: Indivíduos do grupo HC e HR tiveram maior média de idade e maior índice de massa corpórea (60,4; 60,2 anos e 29,6; 29,7 Kg/m2, respectivamente) em relação ao grupo NT (53,2 anos e 26,2 Kg/m2) (P<0,05). HR apresentaram maior nível de creatinina e de redução da função renal (1,1mg/dL e 67,3mL/min/m2) comparados ao HC (0,9mg/dL e 79,3mL/min/m2; P<0,05) e NT (0,8mg/dL e 85,3mL/min/m2; P<0,05). Glicemia e ácido úrico foram maiores e HDL-c menor no grupo HR em comparação aos HC e NT, mas sem significância estatística. Pressão arterial sistólica (PAS) e diastólica (PAD) de consultório foram significantemente maiores no grupo HR (137,1/80,7 mmHg) quando comparados ao HC (124,3/74 mmHg) e NT (117,5/74,3 mmHg). PAS e PAD na MAPA 24h, na vigília e no sono foram maiores em HR (129,4/78,9; 130/80 e 128,3/76,9 mmHg, respectivamente) em comparação ao HC (119,4/72,7; 121,3/75 e 115,7/68,3 mmHg, respectivamente) e NT (114,8/71,8; 117,8/74,8 e 109,3/66,4 mmHg, respectivamente). Frequência cardíaca (FC) e pressão de pulso (PP) foram significantemente mais elevadas no HR (72,4 bpm/min e 52,2 mmHg, respectivamente) do que nos grupos HC (67,5 bpm/min e 47,2 mmHg, respectivamente) e NT (67,3 bpm/min e 42,9 mmHg, respectivamente) durante o período de sono. HR apresentaram menor descenso noturno do que HC e NT (P<0,05). PAS central de 24h, na vigília e no sono foram significantemente maiores nos HR (119,2; 118,8 e 119,8 mmHg, respectivamente) comparadas aos HC (110,4; 111,5 e 109 mmHg, respectivamente) e NT (107,2; 109,2 e 104,2 mmHg, respectivamente). VOP foi maior no HR em comparação a HC e NT nos três períodos avaliados, apesar de não haver significância estatística. Os valores de AIx não apresentaram diferença entre os três grupos em todos os períodos. Em HR, a idade e a VOP foram significantemente associadas à PAC. Houve correlação positiva entre PAS central e PP e entre PAS central e VOP no grupo HR. Conclusão: Hipertensos resistentes apresentaram maior nível de PAC do que hipertensos controlados e normotensos; fato que demonstra maior rigidez arterial nesse grupo e, consequentemente, maior risco cardiovascular.
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Warren, Kristen Marie. "Multichannel Pulse Oximetry: Effectiveness in Reducing HR and SpO2 error due to Motion Artifacts." Digital WPI, 2016. https://digitalcommons.wpi.edu/etd-theses/1219.
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Pulse oximetry is used to measure heart rate (HR) and arterial oxygen saturation (SpO2) from photoplethysmographic (PPG) waveforms. PPG waveforms are highly sensitive to motion artifact (MA), limiting the implementation of pulse oximetry in mobile physiological monitoring using wearable devices. Previous studies have shown that multichannel pulse oximetry can successfully acquire diverse signal information during simple, repetitive motion, thus leading to differences in motion tolerance across channels. In this study, we introduce a multichannel forehead-mounted pulse oximeter and investigate the performance of this novel sensor under a variety of intense motion artifacts. We have developed a multichannel template-matching algorithm that chooses the channel with the least amount of motion artifact to calculate HR and SpO2 every 2 seconds. We show that for a wide variety of random motion, channels respond differently to motion, and the multichannel estimate outperforms single channel estimates in terms of motion tolerance, signal quality, and HR and SpO2 error. Based on 31 data sets of PPG waveforms corrupted by random motion, the mean relative HR error was decreased by an average of 5.6 bpm when the multichannel-switching algorithm was compared to the worst performing channel. The percentage of HR measurements with absolute errors ≤ 5 bpm during motion increased by an average of 27.8 % when the multichannel-switching algorithm was compared to the worst performing channel. Similarly, the mean relative SpO2 error was decreased by an average of 4.3 % during motion when the multichannel-switching algorithm was compared to each individual channel. The percentage of SpO2 measurements with absolute error ≤ 3 % during motion increased by an average of 40.7 % when the multichannel-switching algorithm was compared to the worst performing channel. Implementation of this multichannel algorithm in a wearable device will decrease dropouts in HR and SpO2 measurements during motion. Additionally, the differences in motion frequency introduced across channels observed in this study shows precedence for future multichannel-based algorithms that make pulse oximetry measurements more robust during a greater variety of intense motion.
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雅史, 齋藤. "Non-invasive assessment of arterial stiffness by pulse wave analysis : in vivo measurements and one-dimensional theoretical model." Thesis, https://doors.doshisha.ac.jp/opac/opac_link/bibid/BB12426688/?lang=0, 2012. https://doors.doshisha.ac.jp/opac/opac_link/bibid/BB12426688/?lang=0.
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Ramuka, Piyush R. "Real-Time Adaptive Noise Cancellation in Pulse Oximetry: Accuracy, Processing Speed and Program Memory Considerations." Digital WPI, 2009. https://digitalcommons.wpi.edu/etd-theses/116.
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A wireless, battery operated pulse oximeter system with a forehead mounted optical sensor was designed in our laboratory. This wireless pulse oximeter (WPO) would enable field medics to monitor arterial oxygen saturation (SpO2) and heart rate (HR) information accurately following injuries, thereby help to prioritize life saving medical interventions when resources are limited. Pulse oximeters developed for field-based applications must be resistant to motion artifacts since motion artifacts degrade the signal quality of the photoplethysmographic (PPG) signals from which measurements are derived. This study was undertaken to investigate if accelerometer-based adaptive noise cancellation (ANC) can be used to reduce SpO2 and HR errors induced by motion artifacts typically encountered during field applications. Preliminary studies conducted offline showed that ANC can minimize SpO2 and HR errors during jogging, running, and staircase climbing. An 8th order LMS filter with ì = 0.01 was successfully implemented in the WPO's embedded microcontroller. After real-time adaptive filtering of motion corrupted PPG signals, errors for HR values ranging between 60 - 180BPM were reduced from 12BPM to 6BPM. Similarly, ambient breathing SpO2 errors were reduced from 5% to 2%.
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Tolezani, Elaine Cristina. "Determinantes das propriedades funcionais e estruturais de grandes artérias em uma população de indivíduos adultos saudáveis." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/5/5131/tde-07122012-151544/.
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Alterações das propriedades funcionais e estruturais de grandes artérias são correlacionadas à maior risco cardiovascular em diferentes populações. Recentes diretrizes europeias e brasileiras de hipertensão arterial incluem avaliações da espessura íntima medial (EIM) de carótida e da velocidade de onda de pulso (VOP) aórtica como métodos para avaliação de doença subclínica do paciente hipertenso. Estabelecer valores de referência dos métodos de avaliação da estrutura e da função arteriais e os principais determinantes clínicos e demográficos dos parâmetros obtidos com estes métodos, além de suas correlações, em indivíduos adultos saudáveis, é importante para melhor estratificação dos pacientes. Os objetivos do estudo foram avaliar em indivíduos adultos saudáveis: 1. a distribuição dos valores de VOP aórtica e do diâmetro, da espessura íntima medial e da distensão relativa da artéria carótida, para definir parâmetros de referência. 2. os principais determinantes demográficos e clínicos destes parâmetros e suas correlações.Foram avaliados 210 indivíduos (54% mulheres, idade média 44±13anos) sem história ou evidência de doença cardiovascular atual. A pressão arterial (PA) foi aferida por aparelho automático Omron (HEM 705 CP) com o indivíduo sentado. A medida automática da VOP carótida-femural foi feita pelo aparelho Complior®. As propriedades funcionais e estruturais da carótida (distensão, diâmetro e EIM) foram avaliadas por ultrassom de radiofrequência (WTS®). Todos os indivíduos realizaram avaliação bioquímica.As médias dos valores foram: VOP aórtica (m/s) = 8,7±1,5, diâmetro da carótida (m) = 6617±985, EIM da carótida (m) = 601±131 e distensão relativa da carótida (%) = 5,3±2,1. Não houve diferenças significativas nos parâmetros entre homens e mulheres, assim como entre as raças. Na análise multivariada, os fatores independentemente relacionados aos parâmetros vasculares foram: VOP aórtica = idade (r2 0,22/ p < 0,01), EIM da carótida = idade (r2 0,17 / p < 0,01), diâmetro da carótida = creatinina (r2 0,16 / p = 0,02), distensão relativa da carótida = idade (r2 0,37 / p < 0,01) e pressão arterial diastólica PAD - (r2 0,09 / p < 0,01). Observamos que a VOP teve correlação positiva com EIM (r² - 0,06 / p < 0,01), e correlação inversa com a distensão relativa da carótida (r² - 0,08 / p < 0,01). Em conclusão, em indivíduos saudáveis o principal fator relacionado à medida da rigidez aórtica é a idade, enquanto que a idade e a PAD foram relacionados com a medida funcional da carótida, e o nível de creatinina relacionado ao diâmetro. A estrutura da artéria carótida é diretamente relacionada à medida da rigidez aórtica, que por sua vez é inversamente relacionada à capacidade funcional da artéria carótida<br>Changes of structural and functional properties of large arteries are correlated with increased cardiovascular risk in different populations. Recent European and Brazilian guidelines for hypertension include assessment of carotid intima-media thickness (IMT) and aortic pulse wave velocity (PWV) for evaluation of subclinical disease in hypertensive patients. Thus, to establish reference values for methods that evaluate arterial properties and the main clinical and demographic determinants of the parameters obtained with these methods, as well as their correlation in healthy adult subjects, it is important for better stratification of patients. The objectives of the study were to evaluate in healthy adult subjects: 1. the distribution of aortic PWV values and of the diameter, intima-media thickness and distension of the carotid artery to obtain reference parameters. 2. the main demographic and clinical determinants of these parameters and their correlations. We evaluated 210 subjects (54% women, mean age 44 ± 13anos) with no history or current evidence of cardiovascular disease. Blood pressure (BP) was measured by automatic device Omron (HEM 705 CP) with the subject in a sitting position. The automatic measurement of carotid-femoral PWV was performed by Complior® device. The functional and structural properties of the carotid artery (distension, diameter and IMT) were assessed by ultrasound radiofrequency (WTS®). All subjects underwent biochemical evaluation. The mean values were: aortic PWV (m / s) = 8.7±1.5, carotid diameter (m) = 6617±985, carotid IMT (m) = 601±131 and distension on carotid (% ) = 5.3±2.1. There were no significant differences in parameters according gender or race. In multivariate analysis, the independent factors related to arterial parameters were: aortic PWV = age (r2 - 0.22 / p -< 0.01), carotid IMT = age (r2 - 0.17 / p <0.01 ), carotid diameter = creatinine (r2 - 0.16 / p = 0.02), carotid distension = age (r2 - 0.37 / p < 0.01) and diastolic blood pressure - DBP - (r2 - 0.09 / p< 0.01). We also found that aortic PWV was positively correlated with IMT (r² - 0.06 / p < 0.01) and inversely correlated with the relative distension of the carotid (r² - 0.08 / p < 0.01). In conclusion, in healthy subjects the main factor related to aortic stiffness is age, whereas age and DBP were related to functional measurement of the carotid artery, and creatinine levels related to the diameter. The structure of the carotid artery is directly related to the aortic stiffness, which in turn is inversely related to the functional capacity of the carotid artery.
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Andrade, Danieli Castro Oliveira de. "Avaliação não-invasiva das propriedades da parede arterial em pacientes com síndrome antifosfolípide primária." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/5/5145/tde-10032008-152144/.
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Objetivo: A aterosclerose prematura e acelerada tem sido recentemente reconhecida como um fator adicional de dano vascular nos pacientes com Síndrome Antifosfolípide Primária (SAFP). Esses pacientes podem ser beneficiados com o emprego de métodos para detecção precoce de aterosclerose como a Velocidade de Onda de Pulso (VOP) e o Echo-tracking (ET). Esses métodos têm sido reconhecidos pela capacidade de avaliar de forma não-invasiva a progressão da aterosclerose na parede vascular. Portanto, nosso principal objetivo foi avaliar a aterosclerose prematura nesses pacientes com SAFP. Pacientes e Métodos: 27 pacientes do sexo feminino com SAFP definida pelos critérios de Sapporo e 27 pacientes controles pareadas por sexo, idade e índice de massa corpórea foram selecionadas de forma consecutiva. Todas as pacientes sofreram trombose e foram subdivididas de acordo com o sítio vascular: arterial (n=12) e venoso (n=11). Os critérios de exclusão foram: idade > 55 anos, raça negra, hipertensão descontrolada, uso de corticosteróides e estatinas, diabetes, dislipidemia prévia, gravidez, menopausa, outras trombofilias, colagenoses, doenças vasculares de outras etiologias, obesidade definido por Índice de massa corpórea (IMC) >30 m/kg2 e tabagismo. Todas as pacientes foram submetidas à VOP no leito fêmoro-carotídeo (Complior) e echo-tracking pelo Wall Track System no leito carotídeo para avaliação das propriedades funcionais dos vasos. Resultados: Ambos os grupos SAFP e controles não mostraram diferença em relação à idade (41.5 ± 9.3 vs. 41.2 ± 10.2 anos; p=0.92) e IMC (22.7 ± 3.4 vs. 22.6 ± 3.7 kg/m2; p=0.91). Todas as pacientes apresentaram VOP semelhante às controles (p=0.34), o espessamento íntima-média (EIM) foi semelhante nos dois grupos (p=0.29) assim como os demais parâmetros do echo-tracking como o diâmetro carotídeo (p=0.26), a distensibilidade (p=0.92), os coeficientes de complacência (p=0.36) e o módulo elástico (p=0.78). A pressão sistólica (PS) das pacientes estava aumentada em relação às controles (p=0.02). De acordo com o sítio de trombose, as pacientes com eventos arteriais demonstraram um aumento na VOP em relação àquelas com eventos venosos (p=0.01) mesmo com mesmo EIM (p=0.52). Ambos resultados não foram influenciados pela idade ou duração de doença. Os níveis de colesterol total (p=0.002), LDL (p=0.02) e apolipoproteína B (p=0.03) foram mais altos nas pacientes com SAFP com eventos arteriais exclusivos. Na análise multivariada, observamos correlação da VOP com a idade (r=0.584; p=0.001) e com o diâmetro do vaso (DV) (r=0.407; p=0.04). Foi observada uma correlação positiva da VOP com o colesterol total (r=0.507, p=0.01), LDL (r=0.402, p=0.05), e triglicérides (r=0.583, p=0.003). O EIM apresentou correlação direta com o DV (r=0.393; p=0.04) e com a distensibilidade (r=0.373, p=0.05). Conclusão: A aterosclerose na SAFP apresenta curso peculiar e de forma precoce. A VOP foi um método mais adequado para detectar a disfunção vascular secundária à rigidez arterial, visto que, não foram detectadas alterações vasculares funcionais pelo ET.<br>Objective: Premature and accelerated atherosclerosis has been recently recognized as an additional vascular damage in Primary Antiphospholipid Syndrome (PAPS). These patients could benefit from non-invasive diagnostic methods to detect atherosclerosis as the Pulse Wave Velocity (PWV) and the Echo-Tracking (ET) device. By precise measurement of arterial stiffness, these methods output an indirect way to evaluate the vascular wall lesion progression. Our main objective was to evaluate premature atherosclerosis in PAPS.PATIENTS AND METHODS: 27 female patients with PAPS (Sapporo criteria) and 27 age-, body mass index- and sex-matched controls were consecutively selected. All PAPS patients had previous thrombosis and were subdivided according to the type of vascular exclusive event: arterial (n=12) and venous (n=11). Exclusion criteria were: age >55 years, black race, uncontrolled hypertension, smoking, diabetes, previous dyslipidemia, other thrombophilias, vascular and collagen diseases, corticosteroids and statins use, pregnancy, menopause, and obesity defined as body mass index (BMI)>30 m/kg2. All subjects underwent the PWV in femoral-carotidal bed (Complior) and echo-tracking by a Wall Track System in carotidal bed to analyze vascular wall functional properties. RESULTS: Both groups PAPS and controls did not show any difference regarding age (41.5 ± 9.3 vs. 41.2 ± 10.2 years; p=0.92) and BMI (22.7 ± 3.4 vs. 22.6 ± 3.7 kg/m2; p=0.91). All PAPS patients had PWV values similar to controls (p=0.34). Intima-media thickness (IMT) was also similar between groups (p=0.29) as well as all the other echo tracking parameters such as carotideal diameter (p=0.26), distensibility (p=0.92), compliance coefficients (p=0.36), and elastic modulus (p=0.78) were similar among groups. A higher systolic blood pressure was observed was observed in PAPS patients than controls (p=0.02). According to the site of thrombosis, PAPS patients with exclusive arterial events showed a higher PWV compared to those with venous (p=0.01) but had similar IMT (p=0.52). Both results were not influenced by age or disease duration. Total cholesterol (p=0.002), LDL (p=0.02), and apolipoprotein B (p=0.03) levels were higher in PAPS with exclusive arterial events compared to those with exclusive venous events. Multivariate analysis in PAPS showed that PWV was related to age (r=0.584; p=0.001) and blood vessel diameter (VD) (r=0.407; p=0.04). Moreover, PWV did also positively correlated with total cholesterol (r=0.507, p=0.01), LDL (r=0.402, p=0.05), and triglycerides (r=0.583, p=0.003). IMT also had a positive correlation with VD (r=0.393; p=0.04) and distensibility (r=0.373; p= 0.05). CONCLUSION: Atherosclerosis in PAPS has a peculiar course with an early onset, remarkably in those patients with arterial events. PWV was a sensible method to detect impaired functional vessel related to stiffness since no significant changes were observed in functional vascular properties by Echo- Tracking (ET) device.
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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.
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Tai, Yu Lun Tai. "UPPER- AND LOWER-BODY RESISTANCE EXERCISE WITH AND WITHOUT BLOOD FLOW RESTRICTION IN HEMODYNAMICS, PULSE WAVE REFLECTION, ARTERIAL STIFFNESS, AND AUTONOMIC MODULATION." Kent State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=kent1530616652836558.
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Andersson, Klara, and Paulsson Esther Busch. "Accuracy Validation of Pulse Oximeters used at Hospitals : A Cross-Sectional Study performed in Stockholm." Thesis, KTH, Skolan för teknik och hälsa (STH), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-210030.
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This thesis had the purpose to look into the accuracy of the pulse oximeter, the experienced as well as the actual. A pulse oximeter utilizes optics to non-invasively estimate the oxygen saturation (SO2) in the blood with an indirect value (SpO2). The accuracy of the pulse oximeter and its two belonging sensors (ear and finger) was compared against the method that is considered to give the most reliable value of this parameter, i.e. arterial blood gas test (SaO2). The experienced accuracy was evaluated with the help of a questionnaire. The target group was healthcare professionals at four main hospitals in Stockholm, and further three departments were chosen at each hospital; lung, cardiology, and emergency department. Additional data was collected with help of measurements performed on patients, where readings from pulse oximeters were compared against arterial blood gas tests. Data was collected from two measurement sites on the body, the ear and the finger. Differences between SpO2 and SaO2 as well as differences between ear and finger for the same pulse oximeter were investigated. The result from the two methods indicated that the healthcare professionals were aware of existing deviations between SpO2 and SaO2, and some also had strategies to deal with them. The trend of the collected data was analyzed to draw a conclusion of the most accurate pulse oximeter according to the tests. There was not enough data collected to make any statistical conclusion, but according to the data none of the pulse oximeters fulfilled the set requirement. Differences existed when SpO2 was compared against SaO2, and also when SpO2 from the ear and finger for the same pulse oximeter were compared against each other. According to the data, one pulse oximeter was concluded to be more accurate than the others. Suggestions for future work can be to collect a bigger amount of data to be able to draw a statistical conclusion, and eventually focus on interviews to look deeper into the healthcare professionals’ strategies and workflow.<br>Den här uppsatsen syftade till att undersöka pulsoximeterns mätnoggrannhet, så väl den upplevda som den faktiska. En pulsoximeter utnyttjar optik för att icke-invasivt uppskatta syremättnaden (SO2) i blodet med ett indirekt värde (SpO2). Mätnoggrannheten hos pulsoximetern och dess två sensorer (öra och finger) jämfördes med den metod som anses ge det mest korrekta värdet av denna parameter, dvs. analys av arteriellt blodgastest (SaO2). Den upplevda mätnoggrannheten studerades med hjälp av enkät. Målgruppen var sjukvårdspersonal anställda på fyra stora sjukhus i Stockholm, och vidare valdes tre avdelningar; lungvårds-, hjärtintensivvårds- och akutvårdsavdelningen. Vidare samlades data in genom utförda mätningar på patienter, värden erhållna med hjälp av pulsoximetrar jämfördes med blodgastester. Data samlades in från två mätställen, öra och finger, för respektive pulsoximeter. Skillnader mellan SpO2 och SaO2 samt skillnader mellan öra och finger för samma pulsoximeter undersöktes. Resultatet av de två metoderna visade att sjukvårdspersonalen är väl medvetna om att skillnader existerar mellan SpO2 och SaO2, och även att många hade strategier för att hantera dessa. Trenden hos data som samlades in med hjälp av testerna utnyttjades för att kunna dra en slutsats angående mätnoggrannheten i relation till blodgastester. För lite data samlades in för att kunna dra någon statistisk slutsats, men data pekade på att ingen av de testade pulsoximetrarna uppfyllde den av författarna fastställda accepterade skillnaden. Skillnader visade sig existera vid jämförelse mellan SpO2 och SaO2, och även när SpO2 från örat och finger för samma pulsoximeter jämfördes mot varandra. Enligt data var en av de testade pulsoximeterna mer noggrann än de andra. Förslag på framtida arbete kan vara att samla in mer data för att ta fram ett statistiskt resultat, samt eventuellt komplettera datainsamlingen med intervjuer för att vidare undersöka strategier och arbetssätt hos sjukvårdspersonalen.
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Alvim, Rafael de Oliveira. "Herdabilidade da velocidade de onda de pulso e associação do controle glicêmico e perfil lipídico com a rigidez arterial em uma população brasileira: \"Projeto Corações de Baependi\"." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/5/5131/tde-06062016-135643/.
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INTRODUÇÃO:A rigidez arterial aumentada é um importante determinante do risco cardiovascular e um forte preditor de morbimortalidade. Além disso, estudos demonstram que o enrijecimento vascular pode estar associado a fatores genéticos e metabólicos. Portanto,os objetivos do presente estudo são determinar a herdabilidade da velocidade de onda de pulso (VOP) e avaliar a associação do perfil lipídico e do controle glicêmico com o fenótipo de rigidez arterial em uma população brasileira.MÉTODOS:Foram selecionados 1675 indivíduos (ambos os gêneros com idade entre 18 e 102 anos) distribuídos em 109 famílias residentes no município de Baependi-MG. A VOP carótida-femoral foi avaliada de forma não invasiva através de um dispositivo automático.As variáveis lipídicas e a glicemia de jejum foram determinadas pelo método enzimático colorimétrico. Os níveis de hemoglobina glicada (HbA1c) foram determinados pelo método de cromatografia líquida de alta eficiência. As estimativas da herdabilidade da VOP foram calculadas utilizando-se a metodologia de componentes de variância implementadas no software SOLAR. RESULTADOS: A herdabilidade estimada para a VOP foi de 26%, sendo ajustada para idade, gênero, HbA1c e pressão arterial média. Os níveis de HbA1c foram associados a rigidez arterial, onde a elevação de uma unidade percentual da HbA1c representou um incremento de 54% na chance de risco para rigidez arterial aumentada. As variáveis lipídicas (LDL-c, HDL-c, colesterol não- HDL-c, colesterol total e triglicérides) apresentaram fraca correlação com a VOP. Além disso, uma análise de regressão linear estratificada para idade (ponto de corte >= 45 anos) demonstrou uma relação inversa entre LDL-c e VOP em mulheres com idade >= 45 anos. CONCLUSÃO: Os resultados indicam que a VOP apresenta herdabilidade intermediária (26%); a HbA1c esta fortemente associada a rigidez arterial aumentada; o LDL-c é inversamente relacionado com a VOP em mulheres com idade >= 45 anos, possivelmente devido às alterações metabólicas associadas à falência ovariana<br>INTRODUCTION: Increased central arterial stiffness is an important determinant of cardiovascular risk and a strong predictor of morbimortality. Moreover, studies showed that vascular stiffening can be associated with genetic and metabolic factors. Thus, the aims of this study are to estimate the heritability of pulse wave velocity (PWV) and to assess the association of lipid profile and glycemic control with arterial stiffness in a sample from the Brazilian population. METHODS: For this study, 1675 individuals (both genders aged from 18 to 102 years) were selected and they were distributed within 109 families residents in the municipality of Baependi - MG. The PWV was measured with a non-invasive automatic device. Lipid profile parameters and fasting glucose were determined by enzymatic colorimetric method. HbA1c levels were determined by high-performance liquid chromatography. Variance component approaches implemented in the SOLAR software were applied to estimate the heritability of PWV. RESULTS: Heritability estimates for carotid-femoral PWV was 26%, after adjustment for age, gender, HbA1c, and mean blood pressure. HbA1c levels were associated with arterial stiffness and the elevation of a single unit percentage of HbA1c represented an increase of 54 % in the odds of increased arterial stiffness. The lipid variables (LDL-c, HDL-c, non-HDL-c, total cholesterol and triglycerides) presented weak correlation with PWV. In addition, a linear regression analysis stratified by age (cutoff >= 45 years) showed an inverse relation between LDL-c and PWV in women aged 45 or older. CONCLUSION: Our findings indicate that PWV demonstrated an intermediate heritability (26%); HbA1c proved to be a good marker for risk stratification for increased arterial stiffness; LDL-c was inversely related with PWV in women aged 45 or older, possibly due to the metabolic alterations associated with ovarian failure
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Leitão, Cátia Sofia Jorge. "Optical fibre sensors as a non-invasive technology to the central arterial pressure assessment." Doctoral thesis, Universidade de Aveiro, 2017. http://hdl.handle.net/10773/21653.
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Doutoramento em Engenharia Física<br>Com o presente trabalho pretendeu-se explorar soluções de fibra ótica na aquisição da onda de pulso na artéria carótida, para análise da sua morfologia e cálculo da pressão arterial central.
Foram desenvolvidos três sistemas, dois baseados em redes de Bragg, gravadas em fibra de sílica, e outro em modulação de intensidade, usando fibra ótica de plástico.
O primeiro sensor foi desenvolvido com o objetivo de testar a exequibilidade da utilização de fibra ótica nesta aplicação. Após resultados promissores da sua caracterização e testes em sujeitos, o desenvolvimento dos dois sensores consequentes teve por objetivo o aumento da sensibilidade e facilidade de utilização das sondas, pela melhoria da sua forma, portabilidade e autonomia. A solução baseada em intensidade mostrou-se ainda como um sistema que coligava desempenho a baixo custo, tendo por isso sido submetida a um estudo pré-clínico, comparando o seu desempenho ao de um dispositivo comercial, de natureza eletromecânica, numa pequena coorte de indivíduos saudáveis. Este estudo teve como objetivo investigar a correlação dos resultados obtidos com a sonda de fibra ótica e o dispositivo comercial. Tendo-se obtido uma correlação muito forte entre as duas técnicas, o dispositivo foi proposto para avaliação clínica. O desempenho da sonda foi assim comparado a um dispositivo comercial, numa coorte de indivíduos hipertensos. Foram também levados a cabo testes invasivos, usando como referência ondas de pressão obtidas no lúmen da artéria aorta em contexto de cateterismo cardíaco. Em ambos os estudos clínicos foram obtidos coeficientes de correlação muito fortes e diferenças de pressão média na gama obtida para dispositivos comerciais. Conclui-se assim que o dispositivo baseado em modulação de intensidade surge como uma promissora alternativa de baixo custo aos dispositivos eletromecânicos de avaliação de pressão arterial central disponíveis no mercado.<br>The present study aimed to explore fibre optic solutions in the acquisition of the pulse wave in the carotid artery, to its morphology analysis and central arterial pressure calculation.
Three systems were developed, two based on Bragg gratings, engraved in silica fibre, and another on intensity modulation, using plastic optical fibre.
The first sensor was developed in order to test the feasibility of the fibre optics use in this application. After promising results in the characterization and small tests in subjects, the development of the consequent two sensors had as main goals increasing the probes sensitivity and user-friendliness, by improving its shape, portability and autonomy.
The intensity-based solution proved to be the system that best combined performance to low cost, and thus was subjected to a pre-clinical study, comparing its performance to a commercial device in a small cohort of healthy individuals. This study aimed to investigate the correlation between the results obtained with the fibre optic probe and the commercial device.
Having been obtained a very strong correlation between the two techniques, the device was proposed for clinical evaluation. The probe’s performance was therefore compared to a non-invasive commercial device, in a cohort of hypertensive individuals. Invasive testing was also performed, using as reference pressure waves obtained in the lumen of the aortic artery in cardiac catheterization context.
In both trials very strong correlation coefficients were obtained, as well as medium pressure differences in the range verified for commercial devices. It is concluded that the device based on intensity modulation arises as promising low cost alternative to central arterial pressure assessment electromechanical devices available in the market.
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Dahlén, Elsa, Niclas Bjarnegård, Toste Länne, Fredrik H. Nyström, and 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.
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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.<br><p>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|</p>
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Marshall, Erica M. "The Effects of Bilateral and Unilateral Upper-Body Acute Resistance Exercise on Cardiovascular Function." Kent State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=kent1584477977402023.
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Mueller, Jonathon W. "The effect of differentiation technique utilized in continuous noninvasive blood pressure measurement." University of Akron / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=akron1145295553.
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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.
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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.
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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.
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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.
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Li, Lulu [Verfasser]. "Measuring fluid shear stress with a novel Doppler-derived relative pulse slope index and maximal systolic acceleration approach to detect peripheral arterial disease and to modulate arteriogenesis / Lulu Li." Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2017. http://d-nb.info/113307426X/34.
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