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BACKGROUND: In hemodialysis patients, high body mass index is associated with low mortality while abdominal obesity relates to increased mortality. We aimed to investigate the association between muscle mass, intramuscular fat and abdominal fat measured by abdominal computed tomography (CT), and mortality in this patients population. METHODS: This two-center retrospective cohort study included hemodialysis patients who underwent abdominal CT between January 2013 and December 2018. Skeletal muscle mass index (SMI), muscle radiation attenuation (MRA) as an index of intramuscular fat, and visceral fat to subcutaneous fat ratio (VSR) were calculated using CT images at the third lumbar vertebral level. Multivariate Cox proportional hazards model was used to determine the independent predictors of all-cause, cardiovascular and non-cardiovascular mortalities. RESULTS: The study included 344 patients (median age 71.0 years; female 33.7%), among whom 145 died during a median follow-up of 4.9 years-46 and 99 from cardiovascular and non-cardiovascular causes, respectively. Lower MRA [hazard ratio (HR) 0.71, 95% confidence interval (CI) 0.58-0.87, P = .001] and higher VSR (HR 1.17, 95% CI 1.01-1.37, P = .04) were independently associated with higher all-cause mortality but not with lower SMI (HR 0.87, 95% CI 0.68-1.11, P = .26). Lower MRA (HR 0.51, 95% CI 0.35-0.73, P < .001) and higher VSR (HR 1.29, 95% CI 1.09-1.54, P = .003) were also associated with cardiovascular and non-cardiovascular mortality, respectively. CONCLUSIONS: Intramuscular fat and abdominal fat as measured using abdominal CT in hemodialysis patients are stronger independent predictors of mortality than muscle mass.
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Gordura Abdominal , Músculo Esquelético , Humanos , Feminino , Idoso , Estudos Retrospectivos , Músculo Esquelético/diagnóstico por imagem , Fatores de Risco , Tomografia Computadorizada por Raios X/métodos , Gordura Intra-Abdominal , Diálise Renal/efeitos adversosRESUMO
AIM: Protein-energy wasting (PEW) is a common syndrome in patients undergoing haemodialysis (HD) and is associated with poor prognosis. Bioelectrical impedance analysis (BIA)-derived phase angle (PA) is useful for predicting PEW, but sex and age need to be considered. We aimed to reveal sex-specific cut-off values of PA predicting PEW in HD patients aged ≥65. METHODS: This two-centre retrospective cohort study included patients on HD who underwent BIA. PEW was detected using the International Society of Renal Nutrition and Metabolism (ISRNM) criteria as a reference. The PA was measured using a multifrequency bioimpedance device. Sex-specific cut-off values of PA predicting PEW were detected by receiver-operator characteristic analysis. We investigated the association between PEW determined using sex-specific cut-off values for PA and all-cause mortality. RESULTS: This study included 274 patients undergoing HD, with a median age of 75 (70-80) years, mean PA of 3.8 ± 1.1° and PEW of 43%. Over a median follow-up duration of 1095 (400-1095) days, 111 patients died. Cut-off values of PA predicting PEW were as follows: female, 3.00° (sensitivity, 87.3%; specificity, 77.5%), and male, 3.84° (sensitivity, 77.6%; specificity, 71.4%). The kappa coefficient between sex-specific cut-off values of the PA and ISRNM criteria had a moderate coincidence level of 0.55. PEW detected by PA was independently associated with all-cause mortality (hazard ratio: 2.40; 95% confidence interval: 1.51-3.85; p < .001). CONCLUSIONS: Sex-specific cut-off values for PA in older HD patients may be useful as a screening tool for predicting PEW and mortality.
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AIM: Circulating blood volume (BV) during exercise changes depending on the intensity and duration, and post-exercise hypotension is observed after continuous exercise. We investigated the safety and efficacy of both interval and continuous IDE at anaerobic threshold (AT) levels with respect to hemodynamic stability and dialysis efficiency. METHODS: In this crossover randomized controlled trial, 16 patients on haemodialysis were subjected to three trial arms, including non-IDE, interval-IDE, and continuous-IDE arms. Systolic blood pressure (SBP), BV, and ultraviolet absorbance - an indicator of dialysis efficiency - were continuously measured, and each change was compared between the three arms by two-way analysis of variance. RESULTS: Continuous IDE decreased SBP from post-exercise to the end of dialysis compared with baseline (pre 142.8 ± 19.0 vs. post 127.5 ± 24.5 mmHg, p = .02), whereas interval IDE maintained better SBP levels post-exercise (pre 139.9 ± 17.1 vs. post 140.1 ± 15.8 mmHg, p = 1.0) than continuous IDE (non-IDE 133.2 ± 19.9 vs. interval 140.1 ± 15.8 vs. continuous 127.5 ± 24.5 mmHg, p = .04). Moreover, interval IDE caused less tiredness and few symptoms (p < .05), despite reaching higher intensity than continuous IDE (p = .001). The BV of each IDE arm decreased during exercise and recovered post-exercise to the same level as non-IDE. Ultraviolet absorbance was not different between each arm (p = .16). CONCLUSION: AT-level interval IDE maintains better hemodynamic stability from post-exercise to the end of dialysis and may represent a novel approach that can be effectively performed with fewer symptoms.
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Hemodinâmica , Diálise Renal , Humanos , Diálise Renal/efeitos adversos , Pressão Sanguínea/fisiologia , Volume Sanguíneo/fisiologia , Exercício Físico/fisiologiaRESUMO
OBJECTIVE: Postexercise vagal dysfunction is linked to noncardiovascular mortality in hemodialysis patients, but the mechanism is unknown. This study aimed to determine the association of cardiovagal neuropathy with systemic inflammation, protein-energy wasting, and noncardiovascular hospitalization. METHODS: This 2-center retrospective cohort study analyzed data from 280 hemodialysis patients who underwent exercise test. Patients were assessed for heart rate (HR) recovery (bpm) for 1 minute after exercise, a marker of vagal function, and were divided into 3 categories (Low: ≤ 6, Mid: 7-11, High: ≥ 12 bpm). We followed 1-year changes in the systemic inflammation-based prognostic score (Glasgow Prognostic Score [GPS]), body weight, and creatinine generation rate (CGR), an indicator of muscle mass, as well as 2-year hospitalization. RESULTS: The HR recovery category was associated with serum C-reactive protein and albumin levels and GPS. After 1 year, the low HR recovery category was associated with worsening in GPS (low, 0 [0-0.5]; mid, 0 [0-1]; high, 0 [0-0]), weight (low, 100.0 [96.1-102.5]; mid, 101.3 [98.9-105.0]; high, 100.5 [98.2-102.9]%), and CGR (low, 97.0 [88.5-111.4]; mid, 110.2 [90.9-124.8]; high, 106.2 [95.5-115.5]%), and the correlations with GPS and CGR remained consistent after adjusting for confounders such as exercise capacity and hospitalization during the follow-up period. There were 117 patients hospitalized. Compared to the high HR recovery category, the mid (hazard ratio: 1.8, 95% confidence interval [CI]: 1.1-3.1, P = .02) and low (hazard ratio: 2.4, 95% CI: 1.5-4.0, P = .001) categories were independently associated with an increased risk of all-cause hospitalization. For noncardiovascular disease hospitalization, the low HR recovery category was independently associated with increased risk of hospitalization (hazard ratio: 2.1, 95% CI: 1.2-3.7, P = .007). CONCLUSIONS: Vagal neuropathy in this population can contribute to adverse outcomes associated with systemic inflammation and protein-energy wasting.
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The heart rate (HR) reflects the dynamic behavior of the autonomic nervous system, and HR profiles during the exercise test provide prognostic information. However, there are no reports of these factors in hemodialysis patients. Data from 256 patients (mean 68.8 years old) who underwent an exercise test were statistically analyzed. Patients were evaluated for the percent HR reserve from HR at peak exercise, HR recovery for one minute after peak exercise, and exercise capacity, as well as intradialytic hypotension (IDH). The prevalence of chronotropic incompetence (96.1%), defined as under 80% HR reserve, and abnormal HR recovery (60.5%), defined as under 12 beats, were very common. Eighty-four deaths occurred during the follow-up period (median, 3.8 years). A slow HR recovery under 7 beats was associated with IDH after adjustment (odds ratio 2.7, 95% confidence interval 1.1-6.4). HR recovery under 12 beats (hazard ratio over study period 5.1, 95% confidence interval 2.5-10.5), HR reserve under 26.2% (3.4, 1.7-6.8), and IDH (1.7, 1.1-2.8) were associated with all-cause mortality after adjustment. Considering the confounding of all three variables, only HR recovery under 12 beats remained associated with the all-cause and cause-specific mortality ("cardiovascular" and "non-cardiovascular"). This association was consistent even in subgroup analyses based on the presence of diabetes and cardiovascular disease. Thus, HR profiles during the exercise can reflect potential health conditions related to cardiac autonomic neuropathy in hemodialysis patients that affect IDH and their survival.
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Sistema Nervoso Autônomo , Hipotensão , Idoso , Teste de Esforço , Frequência Cardíaca/fisiologia , Humanos , Hipotensão/etiologia , Diálise Renal/efeitos adversosRESUMO
PURPOSE: Exercise prescription based on a population-specific physiological response can help ensure safe and effective physical interventions. However, as a facile approach for exercise prescription in hemodialysis population that is based on their exercise capacity has not yet been established, the aim of our study was to develop a unique prediction formula for peak heart rate (HR) that can be used in this population. METHODS: This cross-sectional study measured physical function and HR at peak exercise and anaerobic threshold (AT) during cardiopulmonary exercise tests in 126 individuals. Participants were randomly assigned to the development group (n = 78), whose data were used to calculate the prediction equation, or the validation group (n = 48). RESULTS: The HR reserve in this population was significantly lower (0.44 ± 0.20%) and there was a large discrepancy between conventional age-predicted maximal HR and measured peak-HR values (R = 0.36). The average of the ratio between HR at AT point and peak HR was 85% (95% CI, 83.5%-86.4%). The peak-HR prediction equation was based on resting HR, presence of diabetes, physical dysfunction (gait speed < 1.0 m/s), and hypoalbuminemia (< 3.5 g/dL). It showed high prediction accuracy (R2 [95%CI] = 0.71 [0.70-0.71]) with similar correlation coefficients between the development and validation groups (R = 0.82). CONCLUSION: Aerobic exercise based on estimated peak HR < 85% obtained from the equation in this study may enable safe and effective physical intervention in this population.
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Teste de Esforço , Consumo de Oxigênio , Estudos Transversais , Frequência Cardíaca/fisiologia , Humanos , Pessoa de Meia-Idade , Consumo de Oxigênio/fisiologia , Diálise RenalRESUMO
AIM: Hemodialysis (HD) patients have a high prevalence of frailty. The association between frailty and exercise capacity in HD patients has not been established. This study aimed to clarify the relationships between frailty and exercise capacity in HD patients. METHODS: This two-center cross-sectional study included HD patients who performed cardiopulmonary exercise testing. Participants were divided by frailty phenotype into robust, pre-frail, and frail using the revised Japanese version of the Cardiovascular Health Study criteria. Peak oxygen uptake (peakVO2 ) measured by cardiopulmonary exercise testing was compared with each frailty phenotype. The association between peakVO2 and frailty phenotype was analyzed using multivariate linear regression analysis adjusted for age, sex, body mass index diabetes mellitus, cardiovascular disease, cancer, history of fracture, hemoglobin, left ventricle ejection fraction, and percentage of heart rate reserve. RESULTS: The study included 136 patients (median age, 71.0 years; female, 23.5%), with 15.4%, 44.9%, and 39.7% with frailty phenotypes robust, pre-frail, and frail, respectively. PeakVO2 decreased with deterioration of the frailty phenotype (robust, median 15.1 [13.7-18.3] mL/min/kg; pre-frail, median 12.2 [10.5-14.4] mL/min/kg; frail, median 10.6 [9.2-12.5] mL/min/kg, P < 0.05). PeakVO2 decline was significantly associated with frail (B = -2.19, P = 0.004). Modeling individual frailty components showed a significant association between peakVO2 , usual gait speed (B = 2.38, P = 0.04), and low physical activity (B = -1.44, P = 0.004). CONCLUSION: Frailty in HD patients was associated with a decline in exercise capacity. HD patients with frailty need to improve exercise capacity, gait speed, and physical activity. Geriatr Gerontol Int 2023; 23: 795-802.
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Fragilidade , Humanos , Feminino , Idoso , Fragilidade/diagnóstico , Fragilidade/epidemiologia , Fragilidade/complicações , Idoso Fragilizado , Estudos Transversais , Tolerância ao Exercício , Diálise RenalRESUMO
PURPOSE: Intradialytic exercise may improve dialysis efficiency; however, the association between changes in blood volume (BV) related to exercise intensity and solute removal kinetics remains unknown. We herein investigated the relationship between changes in BV with exercise and removal of solute molecules during hemodialysis. METHODS: Each of the 21 hemodialysis patients underwent cardiopulmonary exercise test to measure anaerobic threshold (AT). According to the exercise intensity, patients were classified into two groups, the low group (n = 12), whose intensity was below the AT, and the high group (n = 9), whose intensity was at the AT level. Each patient completed two trial arms of resting and discontinuous exercise dialysis sessions in a randomized manner. RESULTS: The change in BV with the exercise dialysis session in the high group decreased during exercise (p = 0.028) and remained decreased after exercise (p = 0.016), compared with the low group. In the low group, compared with routine sessions, the removal of potassium (p = 0.030), phosphate (p = 0.024), and urea nitrogen (p = 0.065) increased during exercise, but the total removal of these solutes did not change. In the high group, the removal of phosphate (p < 0.001) and urea nitrogen (p = 0.018) after exercise and even total phosphate (p = 0.027) decreased. CONCLUSION: These findings suggest that the removal of small solute molecules is improved during exercise in intradialytic low-intensity exercise with no change in BV, and decreased after exercise in high-intensity exercise with a decrease in BV. CLINICAL TRIALS REGISTRY: Trial retrospectively registered at the UMIN Clinical Trials Registry: study number UMIN000038629 (Registration date: September 7, 2019).
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Falência Renal Crônica , Volume Sanguíneo , Exercício Físico , Feminino , Humanos , Falência Renal Crônica/terapia , Masculino , Nitrogênio , Fosfatos , Projetos Piloto , Diálise Renal , UreiaRESUMO
The 2009 pandemic H1N1 influenza A virus spread quickly worldwide in 2009. Since most of the fatal cases were reported in developing countries, rapid and accurate diagnosis methods that are usable in poorly equipped laboratories are necessary. In this study, a mobile detection system for the 2009 H1N1 influenza A virus was developed using a reverse-transcriptase loop-mediated isothermal amplification (RT-LAMP) kit with a disposable pocket-warmer as a heating device (designated as pwRT-LAMP). The pwRT-LAMP can detect as few as 100 copies of the virus--which is nearly as sensitive as real-time reverse-transcription polymerase chain reaction (RT-PCR)--and does not cross-react with RNA of seasonal influenza viruses. To evaluate the usefulness of the pwRT-LAMP system, nasal swab samples were collected from 56 patients with flu-like symptoms and were tested. Real-time RT-PCR confirmed that the 2009 H1N1 influenza A virus was present in 27 of the 56 samples. Of these 27 positive samples, QuickVue Influenza A+B immunochromatography detected the virus in only 11 samples (11/27; 40.7%), whereas the pwRT-LAMP system detected the virus in 26 of the 56 samples (26/27 of the positive samples; 96.3%). These findings indicate that the mobile pwRT-LAMP system is an accurate diagnostic system for the 2009 H1N1 influenza A virus, and has great potential utility in diagnosing future influenza pandemics.
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Vírus da Influenza A Subtipo H1N1/isolamento & purificação , Influenza Humana/diagnóstico , Influenza Humana/virologia , Técnicas de Amplificação de Ácido Nucleico/métodos , Sistemas Automatizados de Assistência Junto ao Leito , Virologia/métodos , Adulto , Feminino , Humanos , Vírus da Influenza A Subtipo H1N1/genética , Masculino , Pessoa de Meia-Idade , Sensibilidade e EspecificidadeRESUMO
BACKGROUND: Recently, social frailty has been increasingly recognized as a factor associated with adverse health outcomes, including physical disability and mortality. However, there are no studies about the importance of this factor among hemodialysis patients. Therefore, we investigated the relationship between social frailty and early physical dysfunction in this group of patients. METHODS: This was a two-center cross-sectional study. Older patients receiving hemodialysis were prospectively enrolled. Moreover, participants were evaluated for social frailty based on the definition of previous study and for physical function, peak oxygen uptake (peak VO2 ), ventilatory equivalent for carbon dioxide (VE/VCO2 ) slope and heart rate reserve. Then, they were divided into two groups based on the presence of physical frailty. RESULTS: Data collected from 158 individuals were statistically analyzed. The prevalence rate of social frailty was 59.5%. In the non-physical frailty group, social frailty was found to be independently associated with reduced gait speed (P = 0.007), leg strength (P = 0.040) and peak VO2 (P = 0.023), but not with hand grip strength (P = 0.36). In the physical frailty group, there was no association between social frailty and physical function. Moreover, in patients without physical and social frailty, physical function was maintained at above accepted threshold levels, whereas peak VO2 (14.1 ± 3.3 mL/kg/min), VE/VCO2 slope (32.3 ± 5.5) and heart rate reserve (50.8% ± 21.7%) were substantially impaired. CONCLUSIONS: Patients receiving hemodialysis can present with social frailty and exercise intolerance with cardiac dysfunction in the early phase, which may contribute to subsequent dysfunction. Geriatr Gerontol Int 2021; 21: 664-669.
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Fragilidade , Insuficiência Cardíaca , Estudos Transversais , Teste de Esforço , Fragilidade/epidemiologia , Força da Mão , Humanos , Consumo de Oxigênio , Diálise Renal/efeitos adversosRESUMO
BACKGROUND: While both flow-mediated vasodilation (FMD) in the brachial artery (BA), which measures endothelium-dependent vasodilatation, and intima-media thickness (IMT) in the carotid artery are correlated with the prognosis of coronary artery disease (CAD), it is not clear which modality is a better predictor of CAD. Furthermore, it has not been fully determined whether either of these modalities is superior to conventional ST-segment depression on exercise stress electrocardiogram (ECG) as a predictor. Thus, the goal of the present study was to compare the predictive value of FMD, IMT, and stress ECG for CAD prognosis. METHODS AND RESULTS: A total of 103 consecutive patients (62 +/- 9 years old, 79 men) with clinically suspected CAD had FMD and nitroglycerin-induced dilation (NTG-D) in the BA, carotid artery IMT measurement using high-resolution ultrasound, and exercise treadmill testing. The 73 CAD patients and 30 normal coronary patients were followed for 50 +/- 15 months. Fifteen patients had coronary events during this period (1 cardiac death, 2 non-fatal myocardial infarctions, 3 acute heart failures, and 9 unstable anginas). On Kaplan-Meier analysis, only FMD and stress ECG were significant predictors for cardiac events. CONCLUSION: Brachial endothelial function as reflected by FMD and conventional exercise stress testing has comparable prognostic value, whereas carotid artery plaque burden appears to be less powerful for predicting future cardiac events.
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Doença da Artéria Coronariana/diagnóstico por imagem , Doença da Artéria Coronariana/mortalidade , Infarto do Miocárdio/diagnóstico por imagem , Infarto do Miocárdio/mortalidade , Medição de Risco/métodos , Comorbidade , Endotélio Vascular/diagnóstico por imagem , Teste de Esforço/estatística & dados numéricos , Feminino , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Prognóstico , Fatores de Risco , Análise de Sobrevida , Taxa de Sobrevida , UltrassonografiaRESUMO
BACKGROUND: Vasodilator response to acetylcholine (endothelium-dependent dilation) is impaired in the peripheral and coronary circulation in patients with coronary artery disease (CAD). The purpose of this study is to investigate if the vasodilator response to acetylcholine in the brachial artery (BA) correlates with the same response in the coronary artery (CA). STUDY: We measured the flow responses of BA and CA in 57 patients with suspected CAD. Doppler guidewire was placed into the proximal portion of the left BA and the major branch of CA. Acetylcholine was infused at 7.5, 15, and 30 mug/min for 5 min into BA and at 10(-8), 10(-7), 10(-6) M for 3 min into CA, respectively. The flow was calculated by multiplying average peak velocity by cross sectional areas obtained from quantitative angiography. Vasodilator response to acetylcholine was assessed by ratio of acetylcholine-induced flow/baseline flow. RESULTS: A total of 33 CAD patients (CAD group, 61+/-8 years old) and 24 normal coronary patients (NL group, 57+/-12 years old) were investigated. A strong correlation between the vasodilator response to acetylcholine in BA and CA was observed in both CAD and NL groups, only at two moderate doses of acetylcholine (CAD group, r=0.64, p<0.001, NL group, r=0.87, p<0.001, 15 microg/min vs. 10(-7) M; CAD group, r=0.68, p<0.001, NL group, r=0.72, p<0.001, 30 microg/min vs. 10(-6) M). No significant correlation was obtained during low dose acetylcholine infusion. CONCLUSIONS: The brachial artery vasodilator response to optimal acetylcholine doses is a useful surrogate for coronary endothelial function studies.
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Acetilcolina/farmacologia , Artéria Braquial/efeitos dos fármacos , Doença da Artéria Coronariana/fisiopatologia , Vasos Coronários/efeitos dos fármacos , Vasodilatadores/farmacologia , Adulto , Idoso , Velocidade do Fluxo Sanguíneo/efeitos dos fármacos , Pressão Sanguínea/efeitos dos fármacos , Artéria Braquial/fisiopatologia , Circulação Coronária/efeitos dos fármacos , Vasos Coronários/fisiopatologia , Relação Dose-Resposta a Droga , Endotélio Vascular/efeitos dos fármacos , Endotélio Vascular/fisiopatologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estatística como Assunto , Resultado do Tratamento , Vasodilatação/efeitos dos fármacosRESUMO
BACKGROUND: The utility of exercise echocardiography for evaluating remote ischemia due to noninfarct-related artery (n-IRA) lesions in patients with prior myocardial infarction has not been established. METHODS: Quantitative coronary angiography and treadmill exercise echocardiography were performed within 2 weeks in 115 patients with prior myocardial infarction (>6 weeks) and 224 patients without myocardial infarction. Coronary lumen diameter stenosis > or =50% (by angiography) and the lack of a hyperdynamic response on exercise echocardiography were considered significant. Myocardial infarction size was defined as the number of myocardial segments with severe hypokinesis, akinesis, or dyskinesis on echocardiography at rest. RESULTS: For detection of n-IRA lesions in patients with prior myocardial infarction, the sensitivity of exercise echocardiography was similar (78% vs 79%, P = not significant), however, the specificity was significantly lower (77% vs 91%, P <.01) than for detection of significant stenoses in patients without prior myocardial infarction. Angiographic percent-diameter stenosis, presence of collateral vessel, achieved exercise level, and presence of peri-infarct ischemia did not affect the specificity of exercise echocardiography. However, the specificity of exercise echocardiography was significantly lower (69% vs 84%, P <.05) in patients with echocardiographically large infarction (infarction size > or =2) than in patients with small infarction (infarction size <2). CONCLUSION: In patients with prior myocardial infarction, exercise echocardiography showed low specificity for detection of noninfarct-related artery lesions, especially in patients with echocardiographically large myocardial infarction. These characteristics of treadmill exercise echocardiography should be considered when this technique is applied for patients with healed myocardial infarction.
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Doença das Coronárias/diagnóstico , Ecocardiografia , Teste de Esforço , Infarto do Miocárdio/complicações , Idoso , Angiografia Coronária , Doença das Coronárias/complicações , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Sensibilidade e EspecificidadeRESUMO
This clinical study examines the diagnostic accuracy of exercise echocardiography for detecting significant coronary stenoses in infarct-related arteries in patients with healed myocardial infarction. Quantitative coronary angiography and exercise echocardiography using treadmill testing were performed within 2 weeks of each other in 123 patients with a prior myocardial infarction. Coronary lumen diameter stenosis > or =50% by quantitative coronary angiography and the lack of a hyperdynamic response on exercise echocardiography was considered significant. For detection of infarct-related coronary lesions, treadmill exercise echocardiography was highly sensitive (91%) but less specific (59%) than for detection of non-infarct-related artery lesions. The 2 groups of patients with large and small infarct sites had similar sensitivity for detection of residual stenosis of the infarct-related artery (88% vs 96%, p = NS); however, the specificity of the small infarct sites for this purpose was significantly higher than that of the large infarct sites (86% vs 33%, p < 0.01). When remote ischemia was detected on exercise echocardiography, the specificity of exercise echocardiography was significantly lower (33% vs 70%, p < 0.05) than when remote ischemia was not present. Thus, although there is high sensitivity, the specificity of treadmill exercise echocardiography for detecting infarct-related artery lesions is limited. However, high specificity is maintained when the infarct size is small and/or remote ischemia is not present.
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Estenose Coronária/diagnóstico por imagem , Ecocardiografia/métodos , Teste de Esforço/instrumentação , Distribuição de Qui-Quadrado , Angiografia Coronária , Estenose Coronária/fisiopatologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/diagnóstico por imagem , Infarto do Miocárdio/fisiopatologia , Fatores de Risco , Sensibilidade e EspecificidadeRESUMO
BACKGROUND: Chronic mental and physical stress has been suggested to be a trigger for cardiovascular events. In addition, a reduction in levels of intracellular magnesium has been reported to cause vasoconstriction while enhancing platelet-dependent thrombosis. HYPOTHESIS: The purpose of this study was to investigate whether chronic stress affects endothelial function and intracellular magnesium levels in humans. METHODS: Flow-mediated dilation (endothelium-dependent vasodilation) and sublingual nitroglycerin-induced dilation (0.3 mg, endothelium-independent vasodilation) were measured in the brachial artery in 30 healthy male college students, aged 22 +/- 1 years, using high-resolution ultrasound both before and immediately after a 4-week final term examination period. Erythrocyte magnesium concentration was measured simultaneously. All students had chronic sleep deprivation for 4 weeks, during which sleep lasted < 80% of that on ordinary days; in addition, the students were under great stress to pass the examination. This condition was considered to be chronic stress. RESULTS: Chronic stress decreased flow-mediated dilation and erythrocyte magnesium concentration (from 7.4 +/- 3.0 to 3.7 +/- 2.3%, p < 0.05; from 5.7 +/- 0.4 to 5.5 +/- 0.4 mg/ml, p < 0.05, respectively). The change in flow-mediated dilation correlated significantly with that of the erythrocyte magnesium concentration (r = 0.43, p < 0.05), but not with nitroglycerin-induced dilation. CONCLUSIONS: Chronic stress was found to attenuate endothelial function, which may also be associated with a reduction in the intracellular magnesium level in humans.
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Artéria Braquial/fisiopatologia , Magnésio/sangue , Privação do Sono/fisiopatologia , Estresse Fisiológico/fisiopatologia , Vasodilatação/fisiologia , Adulto , Artéria Braquial/diagnóstico por imagem , Artéria Braquial/efeitos dos fármacos , Doença Crônica , Endotélio Vascular/fisiopatologia , Humanos , Deficiência de Magnésio/etiologia , Deficiência de Magnésio/fisiopatologia , Masculino , Nitroglicerina , Fluxo Sanguíneo Regional , Privação do Sono/complicações , Estresse Fisiológico/complicações , Ultrassonografia , Vasodilatação/efeitos dos fármacosRESUMO
Cigarette smoking has been associated with endothelial dysfunction including impaired endothelium-dependent flow-mediated dilation (FMD). In cigarette smokers, increased oxygen-derived free radicals have been suspected of being one of the major causes of endothelial dysfunction, owing possibly to the inactivation of nitric oxide by free radicals. Vitamins C and E are widely used antioxidant vitamins, which have also been reported to effectively improve the endothelial function in several conditions. To test the effect of moderate-term oral antioxidant vitamin supplementation on the endothelial function in smokers, the authors evaluated the combined effect of vitamins C and E, administered in normal dosages, on FMD in young male smokers. A prospective interventional study was performed. In 15 healthy male subjects (mean age, 24.4 +/-2.5 years old). They studied FMD in the brachial artery by using high-resolution ultrasound. The vascular effects of moderate-term oral supplementation with vitamin C (1.0 g/day) and vitamin E (500 mg/day) were determined during reactive hyperemia, which causes endothelium-dependent FMD. They performed a vascular function study 3 times including before vitamin supplement, after 25 days of vitamin supplement, and 4 weeks after the cessation of the vitamin supplement. The flow-mediated dilator response measurements were repeated twice a day before vitamin supplements, and the repeatability obtained from these measurements was found acceptable (variability of FMD <2%). The oral antioxidant vitamin supplement significantly restored FMD (3.8 +/-2.2% vs 5.9 +/-2.5%; p<0.05), however, this effect disappeared 4 weeks after the vitamin supplementations ended. The combined usual dosage of vitamins C and E supplements was found to improve the endothelial function in chronic smokers.
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Antioxidantes/administração & dosagem , Ácido Ascórbico/administração & dosagem , Endotélio Vascular/efeitos dos fármacos , Fumar/tratamento farmacológico , Vitamina E/administração & dosagem , Administração Oral , Adulto , Antioxidantes/farmacologia , Ácido Ascórbico/farmacologia , Artéria Braquial/efeitos dos fármacos , Artéria Braquial/fisiopatologia , Humanos , Masculino , Estudos Prospectivos , Fatores de Tempo , Vitamina E/farmacologiaRESUMO
BACKGROUND: Repeated application of whole-body periodic acceleration (WBPA) upregulates endothelial nitric oxide synthase and improves brachial artery endothelial function (BAEF) as assessed by measurement of flow-mediated vasodilatation (FMD). However, the acute effect of a single application of WBPA on BAEF has not been fully characterized. In addition, although a novel semi-automatic vessel chasing system (UNEXEF18G) has now been developed in Japan, the direct comparison of UNEXEF18G with a conventional method for FMD measures has not been conducted even if UNEXEF18G has already been utilized in a relatively large scale study. METHODS: We have developed a novel semi-automatic vessel chasing system (UNEXEF18G) that can measure FMD on-line, identify time to peak vasodilatation (TPV), and determine the area under the vasodilatation curve (AUC). Thus, 45 min of WBPA was applied in 20 healthy volunteers (age, 34 ± 13 years), and BAEF was measured by UNEXEF18G before and after WBPA. Also, UNEXEF18G measured FMD was compared with those of a conventional FMD measurement method at rest in order to validate a novel UNEXEF18G measured FMD. RESULTS: Single WBPA resulted in a significant increase in FMD (from 6.4 ± 3.4 to 10.7 ± 4.3%, p < 0.01), a significant decrease in TPV and a significant increase in AUC. In the validation study for UNEXEF18G, Bland and Altman analysis showed that UNEXEF18G measured FMD was almost identical to those of the conventional method at rest. CONCLUSION: These data suggest the usefulness of a new UNEXEF18G and that single application of WBPA results in acute improvement in BAEF in humans.