RESUMO
AIMS: Non-invasive indices to evaluate left ventricular changes during ischemic heart failure are needed to quantify the myocardial impairment and the effectiveness of therapeutic manoeuvres. The aims of this work were to calculate the Wall Thickening Fraction (WTF) and the Augmentation Index (AIx) and to assess the relationship between WTF and AIx using data obtained from an animal model with heart failure followed by a myocardial ischemia stage and a reperfusion stage. METHODS: Nine Corriedale sheep that had been monitored for 10 minutes during a basal stage underwent 5-minute myocardial ischemia, followed by 60-minute reperfusion. Seven of them were subjected to an induced heart failure through an overdose of halothane, two of which were treated with intra-aortic counterpulsation during the reperfusion stage. The remaining two animals were monitored during their ischemia-reperfusion stage. RESULTS: Data obtained in the 5 animals suffering from heart failure followed by myocardial ischemia showed that: a) heart failure induction determined decrease in cardiac output, cardiac index and systolic and diastolic aortic pressure (AoP) with respect to their basal values (p<0.05), b) myocardial ischemia decreased the WTF compared with basal and induced heart failure values (p<0.05), c) during the reperfusion stage accompanied by induced heart failure, WTF increased with respect to values observed during the ischemia induction stage (p<0.05); nevertheless, basal values were not recovered after reperfusion (p<0.05). During this 60-minute stage, systolic and diastolic AoP values were lower (p<0.05) than those at the basal stage. CONCLUSION: AIx and WTF values calculated from synchronically recorded values of aortic pressure and left ventricular wall thickness during the reperfusion stage in all animals (n = 9) showed a negative correlation (p<0.05). Analysed data provided evidence of a negative relationship between a left ventricular index of myocardial function and an arterial index obtained from AoP waves.
Assuntos
Insuficiência Cardíaca , Hipotensão , Isquemia Miocárdica , Traumatismo por Reperfusão Miocárdica , Animais , Modelos Animais de Doenças , Insuficiência Cardíaca/diagnóstico , Isquemia , Isquemia Miocárdica/diagnóstico , Traumatismo por Reperfusão Miocárdica/diagnóstico , Reperfusão , Ovinos , Função Ventricular EsquerdaRESUMO
BACKGROUND: The relationship between the increases in pulse pressure (PP) and arterial stiffness determined by aging or systemic hypertension has been widely reported. These findings are supported by large-cohort analyzes conducted in well-known populations, such as Framingham Study. However, there is evidence that an age-PP curvilinear relationship may exist in hypertensive subjects. This study aimed to evaluate the age-related change in pulse pressure and arterial stiffness in a population-based study. METHODS: Carotid-femoral Pulse Wave Velocity (cfPWV) were obtained in 2075 subjects. RESULTS: Age-related changes of PP showed a curvilinear relationship (R=0.39, p<0.0001) in normotensive subjects, with a nadir at around 50 years of age. On the other hand, the age-cfPWV relationship showed a linear and positive correlation (R=0.72, p<0.0001). PP also showed a curvilinear relationship with age (R=0.36, p<0.0001) in hypertensive subjects, with a nadir around 50 years of age. The age-cfPWV relationship showed a linear and positive correlation (R=0.55, p<0.0001). Similar results were observed in the adult population (age≥16 years). Multivariate analysis showed that age, sex, cfPWV, and mean arterial pressure are determinants of PP values in the entire population; however, this result was not uniform when different subgroups were analyzed. CONCLUSION: In conclusion, age-related changes in PP showed a curvilinear relationship and no parallelism with the age-cfPWV relationship for both normotensive and hypertensive subjects. The determinants of PP impact it differently depending on age and the pathological condition of the subject.
Assuntos
Hipertensão , Rigidez Vascular , Adulto , Pressão Arterial , Pressão Sanguínea , Humanos , Hipertensão/diagnóstico , Hipertensão/epidemiologia , Pessoa de Meia-Idade , Análise de Onda de PulsoRESUMO
The effectiveness of intra-aortic balloon pumping (IABP) is currently evaluated using indirect indexes. The diastolic pressure augmentation is quantified using the subendocardial viability ratio (SEVR) and the DABAC/SABAC index (areas beneath the aortic pressure-time signals during the diastolic and systolic periods, respectively). The SEVR requires invasive recordings of left ventricular pressure; the DABAC/SABAC index may represent an alternative, since it only requires an aortic pressure signal. Nonetheless, it has never been used in an animal model of counterpulsated heart failure and ischemia-reperfusion episode. The aims of this work were: (i) to develop an animal model of heart failure, with a myocardial ischemia-reperfusion episode, treated with IABP during the reperfusion period; (ii) to evaluate the effects of the IABP using the SEVR and DABAC/SABAC indices; and (iii) to assess the relationship between both ratios. Cardiovascular parameters were obtained in anesthetized sheep, in which induced heart failure and ischemia-reperfusion episodes were monitored with and without IABP 1:2. Systolic and diastolic blood pressure signals were assessed in the aorta and in the left ventricle. Values of cardiac output and left ventricular wall thickness signals were obtained. Induction of ischemia and heart failure determined decreases in SEVR and DABAC/SABAC indices with respect to their basal stage (0.807 ± 0.118 vs. 0.601 ± 0.107, P < 0.05 and 1.062 ± 0.136 vs. 0.902 ± 0.161, P < 0.05, respectively). Counterpulsated animals whose myocardial reperfusion was accompanied by heart failure showed a significant improvement of wall thickening fraction along time (R2 = 0.7627, P < 0.001). During counterpulsated heart failure accompanied by myocardial reperfusion, the SEVR was positively correlated with DABAC/SABAC index.
Assuntos
Insuficiência Cardíaca/cirurgia , Balão Intra-Aórtico/métodos , Isquemia Miocárdica/cirurgia , Animais , Aorta , Débito Cardíaco , Modelos Animais de Doenças , Insuficiência Cardíaca/etiologia , Humanos , Balão Intra-Aórtico/instrumentação , Masculino , Isquemia Miocárdica/etiologia , Ovinos , Resultado do TratamentoRESUMO
Cardiac contractile dysfunction (CD) is a multifactorial syndrome caused by different acute or progressive diseases which hamper assessing the role of the underlying mechanisms characterizing a defined pathological condition. Mathematical modeling can help to understand the processes involved in CD and analyze their relative impact in the overall response. The aim of this study was thus to use a myocyte-based multiscale model of the circulatory system to simulate the effects of halothane, a volatile anesthetic which at high doses elicits significant acute CD both in isolated myocytes and intact animals. Ventricular chambers built using a human myocyte model were incorporated into a whole circulatory system represented by resistances and capacitances. Halothane-induced decreased sarco(endo)plasmic reticulum Ca2+ (SERCA2a) reuptake pump, transient outward K+ (Ito), Na+-Ca2+ exchanger (INCX) and L-type Ca2+ channel (ICaL) currents, together with ryanodine receptor (RyR2) increased open probability (Po) and reduced myofilament Ca2+ sensitivity, reproduced equivalent decreased action potential duration at 90% repolarization and intracellular Ca2+ concentration at the myocyte level reported in the literature. In the whole circulatory system, model reduction in mean arterial pressure, cardiac output and regional wall thickening fraction was similar to experimental results in open-chest sheep subjected to acute halothane overdose. Effective model performance indicates that the model structure could be used to study other changes in myocyte targets eliciting CD.
Assuntos
Cardiopatias/fisiopatologia , Modelos Cardiovasculares , Contração Miocárdica/fisiologia , Miócitos Cardíacos/fisiologia , Anestésicos Inalatórios/farmacologia , Animais , Modelos Animais de Doenças , Halotano/farmacologia , Cardiopatias/induzido quimicamente , Cardiopatias/patologia , Hemodinâmica/efeitos dos fármacos , Humanos , Masculino , Contração Miocárdica/efeitos dos fármacos , Miócitos Cardíacos/efeitos dos fármacos , OvinosRESUMO
Vascular research in end-stage renal diseases is an interesting field in which the characterization of arterial stiffness proved to be valuable to predict morbidity and mortality. Particularly, patients on renal replacement therapy have been reported to have significant increases in arterial stiffness and cardiovascular mortality. The clinical relevance of the measurement of arterial stiffness is linked to therapeutical and preventive interventions. The purpose of this work is to analyze the results of the scientific research in the field of arterial stiffness, in which hemodialyzed patients were involved, emphasizing on clinical and in-vitro research carried out by our group compared to contributions previously reported in the specialized literature. These investigations are necessary to improve diagnostic strategies and monitor the arterial response to therapeutical interventions in chronic kidney disease.
Assuntos
Artérias/cirurgia , Derivação Arteriovenosa Cirúrgica , Doenças Cardiovasculares/fisiopatologia , Falência Renal Crônica/terapia , Modelos Cardiovasculares , Diálise Renal , Extremidade Superior/irrigação sanguínea , Rigidez Vascular , Animais , Artérias/fisiopatologia , Derivação Arteriovenosa Cirúrgica/efeitos adversos , Derivação Arteriovenosa Cirúrgica/mortalidade , Doenças Cardiovasculares/diagnóstico , Doenças Cardiovasculares/mortalidade , Doenças Cardiovasculares/terapia , Humanos , Falência Renal Crônica/diagnóstico , Falência Renal Crônica/mortalidade , Falência Renal Crônica/fisiopatologia , Diálise Renal/efeitos adversos , Diálise Renal/mortalidade , Medição de Risco , Fatores de Risco , Resultado do Tratamento , Equilíbrio HidroeletrolíticoRESUMO
BACKGROUND: Pulse wave velocity ratio (PWV-ratio), a measure of central-to-peripheral arterial stiffness gradient, is calculated as a quotient between carotid-femoral and carotid-radial PWV (cf-PWV/cr-PWV). This new index has been reported to be significantly associated with increased mortality in hemodialyzed patients. Since several reports showed differences in arterial stiffness regarding the pathway where the vascular access (VA) is, the purpose of this research was: a) to compare arterial stiffness values obtained in the left and right sides of the body in hemodialyzed and non-hemodialyzed patients, and b) to analyze PWV-ratio values obtained on the side of the body where the VA was placed and compare them to its contralateral intact side. Since it is difficult to adequately measure cr-PWV in patients with a VA in the forearm, we measured the carotid- brachial PWV (cb-PWV) and used it to calculate PWV-ratio (cf-PWV/cb-PWV). METHODS: A Pearson's correlation and Bland & Altman analysis were performed in hemodialyzed (n=135) and non-hemodialyzed (n=77) patients, to quantify the equivalence between arterial stiffness parameters (cf-PWV, cb-PWV, PWV-ratio) obtained on each side of the body with respect to its contralateral side. RESULTS: We conclude that PWV-ratio values measured on the side where the VA is placed were significantly higher than those obtained in its contralateral side, in hemodialyzed patients included in this research. Moreover, cf-PWV, cb-PWV and PWV-ratio values obtained on one side of the body were always highly correlated with its contralateral side. CONCLUSION: According to this research, any research involving PWV-ratio should always consider the observed territory.
Assuntos
Derivação Arteriovenosa Cirúrgica , Doenças Cardiovasculares/diagnóstico , Análise de Onda de Pulso , Diálise Renal , Insuficiência Renal Crônica/terapia , Extremidade Superior/irrigação sanguínea , Rigidez Vascular , Adulto , Idoso , Idoso de 80 Anos ou mais , Derivação Arteriovenosa Cirúrgica/efeitos adversos , Doenças Cardiovasculares/etiologia , Doenças Cardiovasculares/fisiopatologia , Estudos de Casos e Controles , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Diálise Renal/efeitos adversos , Insuficiência Renal Crônica/complicações , Insuficiência Renal Crônica/diagnóstico , Insuficiência Renal Crônica/fisiopatologia , Reprodutibilidade dos Testes , Fatores de Risco , Resultado do TratamentoRESUMO
There is little information regarding age-related reference intervals (RIs) of carotid-femoral pulse wave velocity (cfPWV) for large healthy populations in South America. The aims of this study were to determine cfPWV RIs and percentiles in a cohort of healthy children, adolescents, and adults and to generate year-to-year percentile curves and body-height percentile curves for children and adolescents. cfPWV was measured in 1722 healthy participants with no cardiovascular risk factors (9-87 years, 60% men). First, RIs were evaluated for males and females through correlation and covariate analysis. Then, mean and standard deviation age-related equations were obtained for cfPWV using parametric regression methods based on fractional polynomials and age-specific (year-to-year) percentile curves that were defined using the standard normal distribution. Age-specific first, 2.5th, 5th, 10th, 25th, 50th, 75th, 90th, 95th, 97.5th, and 99th percentile curves were calculated. Finally, height-related cfPWV percentile curves for children and adolescents (<21 years) were established. After adjusting for age and blood pressure differences with respect to females, males showed higher cfPWV levels (6.60 vs 6.45 m/s; P < .01). Thus, specific RIs for males and females were reported. The study provides the largest database to date concerning cfPWV in healthy people from Argentina. Specific RIs and percentiles of cfPWV are now available according to age and sex. Specific percentiles of cfPWV according to body height were reported for people younger than 21 years.
Assuntos
Artérias Carótidas/fisiologia , Artéria Femoral/fisiologia , Análise de Onda de Pulso/normas , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Feminino , Voluntários Saudáveis , Humanos , Masculino , Pessoa de Meia-Idade , Valores de Referência , América do Sul , Adulto JovemRESUMO
Increased arterial stiffness is an important determinant of cardiovascular risk, able to predict morbidity and mortality, and closely associated with ageing and blood pressure. The aims of this study were: (1) To determine the age-dependent reference pulse wave velocity (PWV), and compare it with values from hypertensive patients, and (2) to evaluate the impact of isolated and untreated hypertension on arterial stiffness. A total of 1079 patients were enrolled and divided into a control group (NT) of asymptomatic normotensive patients and a group of asymptomatic hypertensive patients (HT). Blood pressure, carotid-femoral PWV, and body mass index were measured in each subject, whose blood was drawn for laboratory tests. Aortic mean PWV in the NT group was 6.85 ± 1.66 m/s, which increased linearly (R2 = 0.62; P < .05) with age. In patients over 50 years of age, PWV was significantly higher than in younger patients (8.35 vs 5.92 m/s, respectively, P < .001). This significant difference persisted when observing male and female patients separately. In the hypertensive group, mean PWV value was 8.04 ± 1.8 m/s (range 4.5-15.8 m/s) and increased (R2 = 0.243; P < .05) with age. The PWV increase in HT was significantly higher (0.93 m/s per decade, P < .001) than in NT (0.44 m/s per decade). Our study provides normal values of PVW per decade, and shows that these values increase with age, especially after 50 years of age, particularly in HT patients. This stiffness growth rate may be responsible for increased cardiovascular risk in both groups.
Assuntos
Envelhecimento/fisiologia , Aorta/fisiopatologia , Artérias Carótidas/fisiopatologia , Hipertensão , Análise de Onda de Pulso/métodos , Rigidez Vascular , Fatores Etários , Idoso , Argentina/epidemiologia , Doenças Assintomáticas , Pressão Sanguínea/fisiologia , Determinação da Pressão Arterial/métodos , Feminino , Humanos , Hipertensão/diagnóstico , Hipertensão/epidemiologia , Hipertensão/fisiopatologia , Masculino , Pessoa de Meia-Idade , Vigilância da População , Fatores SexuaisRESUMO
INTRODUCTION: The etiology of the end-stage renal disease (ESRD) and the hydration status may be involved in the arterial stiffening process observed in hemodialyzed patients. The ratio between carotid-femoral and carotid-radial pulse wave velocity (PWV ratio) was recently proposed to characterize the patient-specific stiffening process. AIMS: to analyze: (1) the PWV-ratio in healthy and hemodialyzed subjects, analyzing potential changes associated to etiologies of the ESRD, (2) the PWV-ratio and hydration status using multiple-frequency bioimpedance and, (3) the effects of hemodialysis on PWV-ratio in a 5-year follow-up. METHODS: PWV-ratio was evaluated in 151 patients differentiated by the pathology determining their ESRD. Total body fluid (TBF), intra and extra cellular fluid (ICF, ECF) were measured in 65 of these patients using bioelectrical-impedance. The association between arterial, hemodynamic or fluid parameters was analyzed. PWV-ratio was evaluated in a group of patients (n = 25) 5 years later (follow-up study). RESULTS: PWV-ratio increased in the ESRD cohort with respect to the control group (1.03 ± 0.23 vs. 1.31 ± 0.37; p < 0.001). PWV-ratio in the diabetic nephropathy group was higher than in all other etiological groups (1.61 ± 0.33; p < 0.05). PWV-ratio was associated with TBF (r = -0.238; p < 0.05), ICF (r = -0.323; p < 0.01), ECF/ICF (r = 0.400; p < 0.001) and ECF/TBF (r = 0.403; p < 0.001). PWV-ratio calculated in ESRD patients in 2007 increased 5 years later (1.14 ± 0.32 vs. 1.43 ± 0.44; p < 0.005). CONCLUSIONS: PWV-ratio increased the most in patients with diabetic nephropathy. PWV ratio was significantly associated with age and body hydration status, but not with the blood pressure. PWV-ratio could be considered a blood pressure-independent parameter, associated with the age and hydration status of the patient.
Assuntos
Aorta/fisiopatologia , Nefropatias Diabéticas/terapia , Falência Renal Crônica/terapia , Análise de Onda de Pulso , Artéria Radial/fisiopatologia , Diálise Renal , Rigidez Vascular , Fatores Etários , Idoso , Pressão Sanguínea , Composição Corporal , Estudos de Casos e Controles , Estudos Transversais , Nefropatias Diabéticas/diagnóstico , Nefropatias Diabéticas/etiologia , Nefropatias Diabéticas/fisiopatologia , Impedância Elétrica , Feminino , Humanos , Falência Renal Crônica/diagnóstico , Falência Renal Crônica/etiologia , Falência Renal Crônica/fisiopatologia , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Diálise Renal/efeitos adversos , Fatores de Risco , Fatores de Tempo , Resultado do Tratamento , Equilíbrio HidroeletrolíticoRESUMO
AIMS: To analyze the early vascular aging (EVA) in end-stage renal disease (ESRD) patients, attempting to determine a potential association between EVA and the etiology of ESRD, and to investigate the association of hemodialysis and EVA in ESRD patients during a 5-year follow-up period. METHODS: Carotid-femoral pulse wave velocity (cfPWV) was obtained in 151 chronically hemodialyzed patients (CHP) and 283 control subjects, and in 25 CHP, who were followed-up after a 5-year lapse. RESULTS: cfPWV increased in ESRD patients compared to control subjects. The cfPWV-age relationship was found to have a steeper increase in ESRD patients. The highest cfPWV and EVA values were observed in patients with diabetic nephropathy. Regression analysis demonstrated a significant reduction of the EVA in HD patients on a 5-year follow-up. CONCLUSION: Patients in ESRD showed higher levels of EVA. cfPWV and EVA differed in ESRD patients depending on their renal failure etiology. CHP showed an EVA reduction after a 5-year follow-up period.