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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Vyhodnocení rychlosti šíření tlakové vlny v lidském těle / Evaluation of pulse wave velocity in the human body

Mezuláníková, Radka January 2013 (has links)
This Mater's thesis deals with the evaluation of pulse wave velocity using multi-channel whole-body impedance cardiography. Data were taken from the group of healthy volunteers whose impedance changes were measured during rest, respiratory maneuvers, tilt and stress exercise. The result of this measurement are values of peaks of pulse wave time shifts towards R-wave. The velocity values towards the thorax electrodes were recalculated on the basis of knowledge about the pulse wave time shifts and the distances from the heart to the scanned locations, which were measured using the arterial segment's lengths.
42

Relationship between determinants of arterial stiffness assessed by diastolic and suprasystolic pulse oscillometry

Teren, Andrej, Beutner, Frank, Wirkner, Kerstin, Löffler, Markus, Scholz, Markus 23 June 2016 (has links) (PDF)
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.
43

Photoplethysmography in noninvasive cardiovascular assessment

Shi, Ping January 2009 (has links)
The electro-optic technique of measuring the cardiovascular pulse wave known as photoplethysmography (PPG) is clinically utilised for noninvasive characterisation of physiological components by dynamic monitoring of tissue optical absorption. There has been a resurgence of interest in this technique in recent years, driven by the demand for a low cost, compact, simple and portable technology for primary care and community-based clinical settings, and the advancement of computer-based pulse wave analysis techniques. PPG signal provides a means of determining cardiovascular properties during the cardiac cycle and changes with ageing and disease. This thesis focuses on the photoplethysmographic signal for cardiovascular assessment. The contour of the PPG pulse wave is influenced by vascular ageing. Contour analysis of the PPG pulse wave provides a rapid means of assessing vascular tone and arterial stiffness. In this thesis, the parameters extracted from the PPG pulse wave are examined in young adults. The results indicate that the contour parameters of the PPG pulse wave could provide a simple and noninvasive means to study the characteristic change relating to arterial stiffness. The pulsatile component of the PPG signal is due to the pumping action of the heart, and thus could reveal the circulation changes of a specific vascular bed. Heart rate variability (HRV) represents one of the most promising quantitative markers of cardiovascular control. Calculation of HRV from the peripheral pulse wave using PPG, called pulse rate variability (PRV), is investigated. The current work has confirmed that the PPG signal could provide basic information about heart rate (HR) and its variability, and highly suggests a good alternative to understanding dynamics pertaining to the autonomic nervous system (ANS) without the use of an electrocardiogram (ECG) device. Hence, PPG measurement has the potential to be readily accepted in ambulatory cardiac monitoring due to its simplicity and comfort. Noncontact PPG (NPPG) is introduced to overcome the current limitations of contact PPG. As a contactless device, NPPG is especially attractive for physiological monitoring in ambulatory units, NICUs, or trauma centres, where attaching electrodes is either inconvenient or unfeasible. In this research, a prototype for noncontact reflection PPG (NRPPG) with a vertical cavity surface emitting laser (VCSEL) as a light source and a high-speed PiN photodiode as a photodetector is developed. The results from physiological experiments suggest that NRPPG is reliable to extract clinically useful information about cardiac condition and function. In summary, recent evidence demonstrates that PPG as a simple noninvasive measurement offers a fruitful avenue for noninvasive cardiovascular monitoring. Key words: Photoplethysmography (PPG), Cardiovascular assessment, Pulse wave contour analysis, Arterial stiffness, Heart rate (HR), Heart rate variability (HRV), Pulse rate variability (PRV), Autonomic nervous system (ANS), Electrocardiogram (ECG).
44

Ultrasonic Methods for Quantitative Carotid Plaque Characterization

Widman, Erik January 2016 (has links)
Cardiovascular diseases are the leading causes of death worldwide and improved diagnostic methods are needed for early intervention and to select the most suitable treatment for patients. Currently, carotid artery plaque vulnerability is typically determined by visually assessing ultrasound B-mode images, which is influenced by user-subjectivity. Since plaque vulnerability is correlated to the mechanical properties of the plaque, quantitative techniques are needed to estimate plaque stiffness as a surrogate for plaque vulnerability, which would reduce subjectivity during plaque assessment. The work in this thesis focused on three noninvasive ultrasound-based techniques to quantitatively assess plaque vulnerability and measure arterial stiffness. In Study I, a speckle tracking algorithm was validated in vitro to assess strain in common carotid artery (CCA) phantom plaques and thereafter applied in vivo to carotid atherosclerotic plaques where the strain results were compared to visual assessments by experienced physicians. In Study II, hard and soft CCA phantom plaques were characterized with shear wave elastography (SWE) by using phase and group velocity analysis while being hydrostatically pressurized followed by validating the results with mechanical tensile testing. In Study III, feasibility of assessing the stiffness of simulated plaques and the arterial wall with SWE was demonstrated in an ex vivo setup in small porcine aortas used as a human CCA model. In Study IV, SWE and pulse wave imaging (PWI) were compared when characterizing homogeneous CCA soft phantom plaques. The techniques developed in this thesis have demonstrated potential to characterize carotid artery plaques. The results show that the techniques have the ability to noninvasively evaluate the mechanical properties of carotid artery plaques, provide additional data when visually assessing B-mode images, and potentially provide improved diagnoses for patients suffering from cerebrovascular diseases. / <p>Doctoral thesis in medical technology and medical sciences</p><p>QC 20160921</p>
45

Avaliação não invasiva das propriedades estruturais de grandes artérias em pacientes com arterite de Takayasu / Noninvasive evaluation of structural properties of large arteries in patients with Takayasu arteritis

Rosa Neto, Nilton Salles 30 July 2013 (has links)
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 / 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
46

Corrélation entre la pression artérielle périphérique et la vitesse d'onde de pouls chez des sujets de plus de 80 ans institutionnalisés / Correlation between peripheral blood pressure and pulse wave velocity in institutionalized subjects above 80 years old

Miljkovic, Darko 18 July 2013 (has links)
Rationnel : La vitesse d'onde de pouls (VOP) est une méthode non invasive d'estimation de la rigidité artérielle. Les recommandations internationales établissent que la VOP est un marqueur puissant du risque cardiovasculaire (CV). La corrélation entre la pression artérielle périphérique et la VOP et leurs influences respectives sur la mortalité ont été peu étudiés chez les sujets âgés. Notre objectif était d'analyser cette corrélation chez les sujets institutionnalisés de plus de 80 ans. Méthodes : PARTAGE (valeur prédictive de la pression artérielle et de la rigidité artérielle chez institutionnalisé la population très âgée) est une étude de cohorte suivant pendant 2 ans 1130 sujets de plus de 80 ans institutionnalisés dans 72 centres en France et en Italie. La corrélation entre pression artérielle systolique et diastolique (PAS et la PAD) et la VOP (mesuré avec un tonomètre PulsePen ®) a été étudié chez 1071 sujets ayant des données de VOP. Résultats : La corrélation entre la PA et la VOP dans notre étude est significative mais faible. Les coefficients de corrélation sont de 0,24 pour la corrélation PAS clinique-VOP, 0,26 pour la corrélation PP-VOP, et 0,30 pour la corrélation PA automesure-VOP. La corrélation est systématiquement plus élevée chez les femmes mais sans atteindre la significativité. Le niveau de corrélation est inversement proportionnel à l'âge : les corrélations les plus fortes sont retrouvées dans la population la plus jeune. Le traitement antihypertenseur n'a pas d'impact sur la corrélation. Conclusion : La faiblesse de la corrélation montre que la PA et la VOP expriment différents phénomènes physiopathologiques de la rigidité artérielle. L'analyse longitudinale de l'étude PARTAGE, mise en perspective avec ceux trouvés dans nos travaux, pourraient permettre de proposer la VOP comme une méthode complémentaire, voire alternative, à la mesure de la PA dans l'évaluation du risque CV dans la population des sujets très âgés / Background: Carotid-femoral pulse wave velocity (PWV) provides a comprehensive non-invasive assessment of arterial stiffness. PWV is now established as a strong marker of cardiovascular disease. The correlation between peripheral blood pressure and PWV and their respective influences on mortality have been poorly studied in the elderly. Our objective was to analyze this correlation in nursing home residents over 80 years of age. Results could ultimately be helpful in implementing strategies for diagnosis and long-term follow-up of the very elderly population. Methods: The PARTAGE (Predictive value of blood pressure and ARTerial stiffness in institutionalized very AGEd population) study is a 2-year cohort study of 1130 subjects living in 72 nursing homes in France and Italy. The correlation between baseline systolic and diastolic blood pressure (SBP and DBP) and baseline PWV (measured with a PulsePen® tonometer) was studied in 1071 subjects with available PWV measurements. Results: Correlations between peripheral blood pressure and PWV were significant but weak: r=0.24 for self-measured SBP, r=0.30 for casual SBP, r=0.11 for self measured DBP, r=0.14 for casual DBP and r=0.26 for casual pulse pressure (PP). A trend for a weaker correlation was observed in the higher age group for self measured SBP and in the lower ADL group for self measured SBP and DBP. The correlations were systematically higher in women compared to men (but did not reach statistical significance) and lower with advanced age group. The correlation was not impacted by antihypertensive. Conclusion: These findings suggest that SBP, DBP and PWV provide different information in the very elderly. The prospective, longitudinal, long term PARTAGE study results will allow further insight; provide additional in-depth information regarding the respective prognostic value of these two measurement methods. NCT00901355
47

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\" / Heritability of pulse wave velocity and association of glycemic control and lipid profile with arterial stiffness in a Brazilian population: \"Baependi Heart Study\"

Alvim, Rafael de Oliveira 28 March 2016 (has links)
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 / 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
48

Avaliação da rigidez arterial e pressão aórtica central em pacientes hipertensos resistentes

Mendes, Alessandra Beatriz Balduino 24 September 2015 (has links)
Submitted by Fabíola Silva (fabiola.silva@famerp.br) on 2016-06-21T13:59:02Z No. of bitstreams: 1 alessandrabeatrizbalduinomendes_dissert.pdf: 1117178 bytes, checksum: 15a5bcd81c5425cf0d4f661ae4b94a04 (MD5) / Made available in DSpace on 2016-06-21T13:59:02Z (GMT). No. of bitstreams: 1 alessandrabeatrizbalduinomendes_dissert.pdf: 1117178 bytes, checksum: 15a5bcd81c5425cf0d4f661ae4b94a04 (MD5) Previous issue date: 2015-09-24 / 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. / 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.
49

Avaliação não invasiva das propriedades estruturais de grandes artérias em pacientes com arterite de Takayasu / Noninvasive evaluation of structural properties of large arteries in patients with Takayasu arteritis

Nilton Salles Rosa Neto 30 July 2013 (has links)
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 / 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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Impaired cerebral vascular function in college-aged African Americans and Caucasian Americans : potential role of Vitamin D and arterial stiffness

Hurr, Chansol 29 October 2013 (has links)
African Americans have increased risk for cardiovascular and cerebral vascular disease relative to Caucasian Americans. While it is generally accepted that arteries become stiffer at a younger age in African Americans; less is known regarding cerebral vascular function / reactivity (CVMR) to hypercapnia in African Americans. Furthermore, little is known regarding the relationship between arterial stiffness and CVMR, particularly in young healthy adults. We hypothesized that African Americans have stiffer arteries (i.e. arterial stiffness) and reduced CVMR during hypercapnia relative to Caucasian Americans. We also hypothesized that there would be a negative relationship between arterial stiffness and CVMR. Lastly, we hypothesized that these responses would be related to a decrease in Vitamin D status in this population and there would be correlation between Vitamin D status and CVMR. In 11 African American and 19 Caucasian American subjects central arterial stiffness was indexed from carotid-femoral pulse wave velocity (PWV). CVMR was assessed by the cerebral vascular conductance (CVC) response to rebreathing-induced hypercapnia. Vitamin D status was assessed from plasma 25(OH) Vitamin D. PWV was elevated in the African Americans (African American: 581.16 ± 27.7 cm/sec vs. Caucasian American: 502.98 ± 17.6 cm/sec; P < 0.01). CVMR was significantly reduced during hypercapnic rebreathing in the African Americans (African American: 3.05 ± 0.38% of baseline/mmHg vs. Caucasian American: 5.09 ± 0.29% of baseline/mmHg; P < 0.001). When data from all subjects was included there was a trend towards a negative relationship (R = 0.32, P = 0.10) between PWV and CVMR. Vitamin D status was significantly lower in African Americans (African American: 14.96 ± 0.97 ng/ml vs. Caucasian American: 32.73 ± 0.99 ng/ml; P < 0.001); however, there was no significant relationship between Vitamin D status and CVMR (R = 0.23 P = 0.23). In conclusion, these data indicate that African Americans have impaired cerebral vascular responses to hypercapnia, stiffer arteries, and lower Vitamin D status when compared with Caucasian Americans. In addition, there may be a negative relationship between CVMR and PWV; however, no significant correlation between Vitamin D status and vascular function including PWV or CVMR was observed in this study. / text

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