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1.
Circulation ; 149(2): 124-134, 2024 01 09.
Artigo em Inglês | MEDLINE | ID: mdl-38031887

RESUMO

BACKGROUND: Primary aldosteronism, characterized by overt renin-independent aldosterone production, is a common but underrecognized form of hypertension and cardiovascular disease. Growing evidence suggests that milder and subclinical forms of primary aldosteronism are highly prevalent, yet their contribution to cardiovascular disease is not well characterized. METHODS: This prospective study included 1284 participants between the ages of 40 and 69 years from the randomly sampled population-based CARTaGENE cohort (Québec, Canada). Regression models were used to analyze associations of aldosterone, renin, and the aldosterone-to-renin ratio with the following measures of cardiovascular health: arterial stiffness, assessed by central blood pressure (BP) and pulse wave velocity; adverse cardiac remodeling, captured by cardiac magnetic resonance imaging, including indexed maximum left atrial volume, left ventricular mass index, left ventricular remodeling index, and left ventricular hypertrophy; and incident hypertension. RESULTS: The mean (SD) age of participants was 54 (8) years and 51% were men. The mean (SD) systolic and diastolic BP were 123 (15) and 72 (10) mm Hg, respectively. At baseline, 736 participants (57%) had normal BP and 548 (43%) had hypertension. Higher aldosterone-to-renin ratio, indicative of renin-independent aldosteronism (ie, subclinical primary aldosteronism), was associated with increased arterial stiffness, including increased central BP and pulse wave velocity, along with adverse cardiac remodeling, including increased indexed maximum left atrial volume, left ventricular mass index, and left ventricular remodeling index (all P<0.05). Higher aldosterone-to-renin ratio was also associated with higher odds of left ventricular hypertrophy (odds ratio, 1.32 [95% CI, 1.002-1.73]) and higher odds of developing incident hypertension (odds ratio, 1.29 [95% CI, 1.03-1.62]). All the associations were consistent when assessing participants with normal BP in isolation and were independent of brachial BP. CONCLUSIONS: Independent of brachial BP, a biochemical phenotype of subclinical primary aldosteronism is negatively associated with cardiovascular health, including greater arterial stiffness, adverse cardiac remodeling, and incident hypertension.


Assuntos
Doenças Cardiovasculares , Hiperaldosteronismo , Hipertensão , Masculino , Humanos , Adulto , Pessoa de Meia-Idade , Idoso , Feminino , Aldosterona , Remodelação Ventricular , Hipertrofia Ventricular Esquerda/diagnóstico por imagem , Hipertrofia Ventricular Esquerda/epidemiologia , Hipertrofia Ventricular Esquerda/complicações , Renina , Doenças Cardiovasculares/epidemiologia , Doenças Cardiovasculares/complicações , Estudos Prospectivos , Estudos de Coortes , Análise de Onda de Pulso , Hipertensão/complicações , Hiperaldosteronismo/complicações , Hiperaldosteronismo/epidemiologia , Átrios do Coração
2.
Am J Physiol Endocrinol Metab ; 326(5): E616-E625, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38477665

RESUMO

Metabolic-associated fatty liver disease (MAFLD) has been identified as risk factor of incident type 2 diabetes (T2D), but the underlying postprandial mechanisms remain unclear. We compared the glucose metabolism, insulin resistance, insulin secretion, and insulin clearance post-oral glucose tolerance test (OGTT) between individuals with and without MAFLD. We included 50 individuals with a body mass index (BMI) between 25 and 40 kg/m2 and ≥1 metabolic alteration: increased fasting triglycerides or insulin, plasma glucose 5.5-6.9 mmol/L, or glycated hemoglobin 5.7-5.9%. Participants were grouped according to MAFLD status, defined as hepatic fat fraction (HFF) ≥5% on MRI. We used oral minimal model on a frequently sampled 3 h 75 g-OGTT to estimate insulin sensitivity, insulin secretion, and pancreatic ß-cell function. Fifty percent of participants had MAFLD. Median age (IQR) [57 (45-65) vs. 57 (44-63) yr] and sex (60% vs. 56% female) were comparable between groups. Post-OGTT glucose concentrations did not differ between groups, whereas post-OGTT insulin concentrations were higher in the MAFLD group (P < 0.03). Individuals with MAFLD exhibited lower insulin clearance, insulin sensitivity, and first-phase pancreatic ß-cell function. In all individuals, increased insulin incremental area under the curve and decreased insulin clearance were associated with HFF after adjusting for age, sex, and BMI (P < 0.02). Among individuals with metabolic alterations, the presence of MAFLD was characterized mainly by post-OGTT hyperinsulinemia and reduced insulin clearance while exhibiting lower first phase ß-cell function and insulin sensitivity. This suggests that MAFLD is linked with impaired insulin metabolism that may precede T2D.NEW & NOTEWORTHY Using an oral glucose tolerance test, we found hyperinsulinemia, lower insulin sensitivity, lower insulin clearance, and lower first-phase pancreatic ß-cell function in individuals with MAFLD. This may explain part of the increased risk of incident type 2 diabetes in this population. These data also highlight implications of hyperinsulinemia and impaired insulin clearance in the progression of MAFLD to type 2 diabetes.


Assuntos
Glicemia , Teste de Tolerância a Glucose , Hiperinsulinismo , Resistência à Insulina , Insulina , Hepatopatia Gordurosa não Alcoólica , Humanos , Feminino , Masculino , Pessoa de Meia-Idade , Hiperinsulinismo/metabolismo , Hiperinsulinismo/sangue , Idoso , Adulto , Glicemia/metabolismo , Hepatopatia Gordurosa não Alcoólica/metabolismo , Insulina/sangue , Insulina/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/complicações , Período Pós-Prandial , Secreção de Insulina , Índice de Massa Corporal , Fígado/metabolismo , Células Secretoras de Insulina/metabolismo
3.
Am J Physiol Endocrinol Metab ; 325(1): E99-E105, 2023 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-37285597

RESUMO

Low circulating levels of insulin-like growth-factor binding protein-2 (IGFBP-2) have been associated with increased adiposity and metabolic alterations such as insulin resistance, dyslipidemia, and nonalcoholic fatty liver disease in individuals with obesity. However, whether IGFBP-2 affects energy metabolism in the early stages of these disorders remains unclear. Herein, we hypothesized that plasma IGFBP-2 concentrations are inversely associated with early liver fat accumulation and alterations in lipid and glucose homeostasis in apparently healthy and asymptomatic men and women. Three hundred thirty-three middle-aged Caucasian men and women apparently healthy and without cardiovascular symptoms were enrolled for a cross-sectional cardiometabolic imaging study. Individuals with BMI ≥ 40 kg/m2, cardiovascular disease, dyslipidemia, hypertension, and diabetes were excluded. Fasting glucose and lipid profiles were measured and an oral glucose tolerance test was performed. Liver fat content was assessed by magnetic resonance spectroscopy. Volume of visceral adipose tissue (VAT) was evaluated by magnetic resonance imaging. Plasma IGFBP-2 levels were quantified by ELISA. Participants with low IGFBP-2 levels were characterized by a higher body fat mass (P < 0.0001), insulin resistance (P < 0.0001), higher plasma triglyceride (TG) (P < 0.0001), and lower HDL-cholesterol levels (P < 0.0001) in a sex-independent manner. IGFBP-2 levels were inversely correlated with hepatic fat fraction in both men (r = -0.36, P < 0.0001) and women (r = -0.40, P < 0.0001). IGFBP-2 concentrations were negatively associated with hepatic fat fraction independently of age and VAT in both men (R2 = 0.23, P = 0.012) and women (R2 = 0.27, P = 0.028). In conclusion, our findings show that even in asymptomatic, apparently healthy individuals, low IGFBP-2 levels are associated with a more deteriorated cardiometabolic risk profile and with a high hepatic fat content in a VAT-independent manner. However, IGFBP-2 does not appear to influence the established sexual dimorphism observed for metabolic variables and hepatic fat fraction. Additional studies are required to better understand the relationships between IGFBP-2 and liver fat content.NEW & NOTEWORTHY Faced with a paucity of reliable clinical etiologic markers for fatty liver, this research article demonstrates, for the first time, that low blood levels of the protein IGFBP-2 are associated with a more deteriorated cardiometabolic risk profile and with a high hepatic fat content independently of visceral fat volume and sex, even in asymptomatic, apparently healthy individuals.


Assuntos
Doenças Cardiovasculares , Hipercolesterolemia , Resistência à Insulina , Masculino , Pessoa de Meia-Idade , Humanos , Feminino , Proteína 2 de Ligação a Fator de Crescimento Semelhante à Insulina/metabolismo , Estudos Transversais , Obesidade/metabolismo , Triglicerídeos/metabolismo , Fígado/diagnóstico por imagem , Fígado/metabolismo , Hipercolesterolemia/metabolismo , Doenças Cardiovasculares/metabolismo , Glucose/metabolismo , Metaboloma , Gordura Intra-Abdominal/metabolismo
4.
Curr Atheroscler Rep ; 24(4): 185-195, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35235165

RESUMO

PURPOSE OF REVIEW: Despite its prevalence and well-documented impact on population health, obesity has not emerged as a strong independent risk factor for cardiovascular disease after control for intermediate risk factors. The purpose of this brief narrative review is to highlight results from imaging studies that have not only documented the remarkable heterogeneity of body fat topography but also the importance of visceral adiposity as a key body fat depot associated with cardiovascular disease risk and type 2 diabetes. RECENT FINDINGS: Simple tools are also discussed in order to refine cardiometabolic risk assessment in persons with overweight/obesity. It is proposed that four lifestyle vital signs should be considered in clinical practice to improve discrimination of health risk in individuals with overweight/obesity: waist circumference as a simple marker of abdominal adiposity, cardiorespiratory fitness, overall diet quality, and level of reported physical activity. Heterogeneity of obesity is proposed as an example of a condition that would benefit from a precision lifestyle medicine approach.


Assuntos
Doenças Cardiovasculares , Diabetes Mellitus Tipo 2 , Adiposidade , Índice de Massa Corporal , Doenças Cardiovasculares/complicações , Doenças Cardiovasculares/etiologia , Diabetes Mellitus Tipo 2/complicações , Humanos , Obesidade/complicações , Obesidade/epidemiologia , Sobrepeso/complicações , Fatores de Risco
5.
J Cardiovasc Magn Reson ; 24(1): 2, 2022 01 03.
Artigo em Inglês | MEDLINE | ID: mdl-34980185

RESUMO

BACKGROUND: Despite the growing utility of cardiovascular magnetic resonance (CMR) for cardiac morphology and function, sex and age-specific normal reference values derived from large, multi-ethnic data sets are lacking. Furthermore, most available studies use a simplified tracing methodology. Using a large cohort of participants without history of cardiovascular disease (CVD) or risk factors from the Canadian Alliance for Healthy Heart and Minds, we sought to establish a robust set of reference values for ventricular and atrial parameters using an anatomically correct contouring method, and to determine the influence of age and sex on ventricular parameters. METHODS AND RESULTS: Participants (n = 3206, 65% females; age 55.2 ± 8.4 years for females and 55.1 ± 8.8 years for men) underwent CMR using standard methods for quantitative measurements of cardiac parameters. Normal ventricular and atrial reference values are provided: (1) for males and females, (2) stratified by four age categories, and (3) for different races/ethnicities. Values are reported as absolute, indexed to body surface area, or height. Ventricular volumes and mass were significantly larger for males than females (p < 0.001). Ventricular ejection fraction was significantly diminished in males as compared to females (p < 0.001). Indexed left ventricular (LV) end-systolic, end-diastolic volumes, mass and right ventricular (RV) parameters significantly decreased as age increased for both sexes (p < 0.001). For females, but not men, mean LV and RVEF significantly increased with age (p < 0.001). CONCLUSION: Using anatomically correct contouring methodology, we provide accurate sex and age-specific normal reference values for CMR parameters derived from the largest, multi-ethnic population free of CVD to date. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, NCT02220582. Registered 20 August 2014-Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT02220582 .


Assuntos
Ventrículos do Coração , Função Ventricular Esquerda , Fatores Etários , Canadá , Feminino , Ventrículos do Coração/diagnóstico por imagem , Humanos , Imagem Cinética por Ressonância Magnética , Espectroscopia de Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Valores de Referência , Fatores Sexuais , Volume Sistólico
6.
J Cardiovasc Magn Reson ; 23(1): 124, 2021 11 04.
Artigo em Inglês | MEDLINE | ID: mdl-34732204

RESUMO

BACKGROUND: Phase contrast (PC) cardiovascular magnetic resonance (CMR) in the ascending aorta (AAo) is widely used to calculate left ventricular (LV) stroke volume (SV). The accuracy of PC CMR may be altered by turbulent flow. Measurement of SV at another site is suggested in the presence of aortic stenosis, but very few data validates the accuracy or inaccuracy of PC in that setting. Our objective is to compare flow measurements obtained in the AAo and LV outflow tract (LVOT) in patients with aortic stenosis. METHODS: Retrospective analysis of patients with aortic stenosis who had CMR and echocardiography. Patients with mitral regurgitation were excluded. PC in the AAo and LVOT were acquired to derive SV. LV SV from end-systolic and end-diastolic tracings was used as the reference measure. A difference ≥ 10% between the volumetric method and PC derived SVs was considered discordant. Metrics of turbulence and jet eccentricity were assessed to explore the predictors of discordant measurements. RESULTS: We included 88 patients, 41% with bicuspid aortic valve. LVOT SV was concordant with the volumetric method in 79 (90%) patients vs 52 (59%) patients for AAo SV (p = 0.015). In multivariate analysis, aortic stenosis flow jet angle was a strong predictor of discordant measurement in the AAo (p = 0.003). Mathematical correction for the jet angle improved the concordance from 59 to 91%. Concordance was comparable in patients with bicuspid and trileaflet valves (57% and 62% concordance respectively; p = 0.11). Accuracy of SV measured in the LVOT was not influenced by jet eccentricity. For aortic regurgitation quantification, PC in the AAo had better correlation to volumetric assessments than LVOT PC. CONCLUSION: LVOT PC SV in patients with aortic stenosis and eccentric jet might be more accurate compared to the AAo SV. Mathematical correction for the jet angle in the AAo might be another alternative to improve accuracy.


Assuntos
Estenose da Valva Aórtica , Valva Aórtica , Valva Aórtica/diagnóstico por imagem , Estenose da Valva Aórtica/diagnóstico por imagem , Humanos , Espectroscopia de Ressonância Magnética , Valor Preditivo dos Testes , Estudos Retrospectivos , Volume Sistólico
7.
BMC Med Ethics ; 22(1): 145, 2021 10 28.
Artigo em Inglês | MEDLINE | ID: mdl-34711210

RESUMO

BACKGROUND: In the Canadian Alliance for Healthy Hearts and Minds (CAHHM) cohort, participants underwent magnetic resonance imaging (MRI) of the brain, heart, and abdomen, that generated incidental findings (IFs). The approach to managing these unexpected results remain a complex issue. Our objectives were to describe the CAHHM policy for the management of IFs, to understand the impact of disclosing IFs to healthy research participants, and to reflect on the ethical obligations of researchers in future MRI studies. METHODS: Between 2013 and 2019, 8252 participants (mean age 58 ± 9 years, 54% women) were recruited with a follow-up questionnaire administered to 909 participants (40% response rate) at 1-year. The CAHHM policy followed a restricted approach, whereby routine feedback on IFs was not provided. Only IFs of severe structural abnormalities were reported. RESULTS: Severe structural abnormalities occurred in 8.3% (95% confidence interval 7.7-8.9%) of participants, with the highest proportions found in the brain (4.2%) and abdomen (3.1%). The majority of participants (97%) informed of an IF reported no change in quality of life, with 3% of participants reporting that the knowledge of an IF negatively impacted their quality of life. Furthermore, 50% reported increased stress in learning about an IF, and in 95%, the discovery of an IF did not adversely impact his/her life insurance policy. Most participants (90%) would enrol in the study again and perceived the MRI scan to be beneficial, regardless of whether they were informed of IFs. While the implications of a restricted approach to IF management was perceived to be mostly positive, a degree of diagnostic misconception was present amongst participants, indicating the importance of a more thorough consent process to support participant autonomy. CONCLUSION: The management of IFs from research MRI scans remain a challenging issue, as participants may experience stress and a reduced quality of life when IFs are disclosed. The restricted approach to IF management in CAHHM demonstrated a fair fulfillment of the overarching ethical principles of respect for autonomy, concern for wellbeing, and justice. The approach outlined in the CAHHM policy may serve as a framework for future research studies. Clinical trial registration https://clinicaltrials.gov/ct2/show/NCT02220582 .


Assuntos
Achados Incidentais , Qualidade de Vida , Idoso , Encéfalo/diagnóstico por imagem , Canadá , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade
8.
Am J Physiol Endocrinol Metab ; 319(3): E548-E556, 2020 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-32715747

RESUMO

Cardiorespiratory fitness (CRF) is positively associated with insulin sensitivity, whereas excessive levels of visceral adipose tissue (AT) and liver fat (LF) are both associated with insulin resistance and impaired plasma glucose-insulin homeostasis. To what extent levels of visceral AT and LF content contribute to the relationship between CRF and indices of plasma glucose-insulin homeostasis is uncertain. Our objective was to explore the interactions among CRF, visceral AT, and LF with glucose tolerance/insulin levels in asymptomatic and apparently healthy individuals. CRF was measured in 135 women and 177 men with a maximal treadmill graded exercise test. Indices of plasma glucose-insulin homeostasis were derived from a 3-h oral glucose tolerance test (OGTT) performed in the morning after a 12-h fast. Visceral AT levels and LF content were measured using magnetic resonance imaging and spectroscopy. For any given CRF level, women presented significantly lower visceral AT and LF than men as well as lower homeostasis model assessment of insulin resistance (HOMA-IR) and plasma glucose-insulin levels during the OGTT compared with men. In both sexes, there were significant negative correlations between CRF and HOMA-IR as well as glucose and insulin levels measured during the OGTT. Both glucose and insulin levels during the OGTT correlated positively with visceral AT and LF. In women and men, being in the top CRF tertile was associated with low levels of visceral AT and LF. Multivariable linear regression analyses suggested that visceral AT and LF were plausible mediators of the association between CRF and indices of plasma glucose-insulin homeostasis.


Assuntos
Tecido Adiposo/metabolismo , Glicemia/metabolismo , Aptidão Cardiorrespiratória/fisiologia , Gorduras/metabolismo , Insulina/metabolismo , Fígado/metabolismo , Adulto , Idoso , Composição Corporal , Dieta , Eletrocardiografia , Teste de Esforço , Feminino , Teste de Tolerância a Glucose , Homeostase , Humanos , Resistência à Insulina , Testes de Função Hepática , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade
9.
J Biomed Inform ; 94: 103185, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31028874

RESUMO

OBJECTIVE: To develop machine learning models for classifying the severity of opioid overdose events from clinical data. MATERIALS AND METHODS: Opioid overdoses were identified by diagnoses codes from the Marshfield Clinic population and assigned a severity score via chart review to form a gold standard set of labels. Three primary feature sets were constructed from disparate data sources surrounding each event and used to train machine learning models for phenotyping. RESULTS: Random forest and penalized logistic regression models gave the best performance with cross-validated mean areas under the ROC curves (AUCs) for all severity classes of 0.893 and 0.882 respectively. Features derived from a common data model outperformed features collected from disparate data sources for the same cohort of patients (AUCs 0.893 versus 0.837, p value = 0.002). The addition of features extracted from free text to machine learning models also increased AUCs from 0.827 to 0.893 (p value < 0.0001). Key word features extracted using natural language processing (NLP) such as 'Narcan' and 'Endotracheal Tube' are important for classifying overdose event severity. CONCLUSION: Random forest models using features derived from a common data model and free text can be effective for classifying opioid overdose events.


Assuntos
Analgésicos Opioides/administração & dosagem , Overdose de Drogas , Aprendizado de Máquina , Fenótipo , Registros Eletrônicos de Saúde , Humanos , Índice de Gravidade de Doença
10.
J Acoust Soc Am ; 146(1): 595, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31370568

RESUMO

Locadiff is a method for imaging local structural changes in a random, heterogeneous medium. It relies on the combination of a forward model to calculate the sensitivity kernel of the source-receiver pairs, with an inversion method to determine the position of the changes. So far, the sensitivity kernel has been evaluated based on an analytical solution of the diffusion equation, which lacks the flexibility to handle problems where the domain has boundaries with an irregular shape. Moreover, the accuracy of the previous inversion method, based on linear algebra tools, was very sensitive to the values of the inversion parameters. This paper introduces a more generic approach to solve both these issues. The first problem is tackled by the implementation of a numerical method as an alternative for solving the diffusion equation. The second problem is tackled by the introduction of enhanced optimization algorithms to improve the stability of the inversion. This improved version of Locadiff is validated via both numerical examples and experimental data from an actual civil engineering problem.

11.
J Acoust Soc Am ; 145(3): 1600, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31067957

RESUMO

The deployment of three drifting seismic stations on the Arctic sea ice during the winter of 2014-2015 with station inter-spacing between 30 and 80 km enables the characterization of the coherent seismic wavefield at these scales through the use of array methods. Two distinct vibrational modes are observed, corresponding to the fast and non-dispersive horizontally-polarized shear (SH) mode and the slow and dispersive flexural, infragravity mode (ice swell). The excitation of these two modes is not synchronous. The activation of the infragravity mode is linked to the arrival of energetic, dispersive wavetrains that can be readily seen on individual spectrograms, and that, as previous studies have shown, are likely to have their origins in distant storms. In contrast, the SH mode is excited at other time intervals and cannot be isolated on the recording of single stations due to the broadband and emergent nature of these wavetrains; given the horizontal polarization of these waves, the authors hypothesize that SH waves are caused by episodes of rapid SH deformation along major leads located outside the station network. The existence of horizontally-polarized waves propagating over long distances opens the possibility of monitoring ice deformation at the scale of the Arctic basin with unprecedented time resolution.

12.
Can J Physiol Pharmacol ; 95(8): 878-887, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28520469

RESUMO

Prediction of coronary events remains elusive. Carotid atherosclerosis may be a surrogate for coronary risk, as carotid and coronary diseases occur simultaneously - albeit at times with a weak association - depending on clinical presentation. We investigated carotid and coronary atherosclerosis in men with new-onset unstable coronary artery disease (CAD) presenting with acute ST-segment elevation myocardial infarction (STEMI) vs. long-standing severe chronic stable angina (CSA). Bilateral carotid artery and 3-vessel coronary artery atherosclerosis burdens were measured within 1 month, respectively, by 3D-volumetric carotid magnetic resonance imaging and coronary angiography-derived modified CASS-50 score. Men with STEMI (n = 50) and long-standing CSA (n = 50), matched for age, were enrolled (58.6 ± 8.8 years). All of them had carotid atherosclerosis. Atherosclerosis burden was greater in the carotid arteries of STEMI vs. CSA (wall volume: 196.2 ± 44.4 vs. 169.2 ± 38.0 mm3/4 mm, p = 0.002), but greater in the coronary arteries of CSA vs. STEMI (modified CASS-50 score: 3 vs. 1, p < 0.0001). Normalized wall index (NWI) of internal carotid was associated with modified CASS-50 score in STEMI (ρ = 0.40, p = 0.022) and in CSA (ρ = -0.39, p = 0.031). Carotid atherosclerosis was observed in all CAD patients, and atherosclerosis burden in carotid and in coronary arteries varied according to clinical presentation.


Assuntos
Doenças das Artérias Carótidas/complicações , Doença da Artéria Coronariana/complicações , Doença Aguda , Doença Crônica , Doença da Artéria Coronariana/diagnóstico por imagem , Doença da Artéria Coronariana/fisiopatologia , Feminino , Hemodinâmica , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade
13.
J Acoust Soc Am ; 142(5): 2873, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-29195456

RESUMO

The decline of Arctic sea ice extent is one of the most spectacular signatures of global warming, and studies converge to show that this decline has been accelerating over the last four decades, with a rate that is not reproduced by climate models. To improve these models, relying on comprehensive and accurate field data is essential. While sea ice extent and concentration are accurately monitored from microwave imagery, an accurate measure of its thickness is still lacking. Moreover, measuring observables related to the mechanical behavior of the ice (such as Young's modulus, Poisson's ratio, etc.) could provide better insights in the understanding of sea ice decline, by completing current knowledge so far acquired mostly from radar and sonar data. This paper aims at demonstrating on the laboratory scale that these can all be estimated simultaneously by measuring seismic waves guided in the ice layer. The experiment consisted of leaving a water tank in a cold room in order to grow an ice layer at its surface. While its thickness was increasing, ultrasonic guided waves were generated with a piezoelectric source, and measurements were subsequently inverted to infer the thickness and mechanical properties of the ice with very good accuracy.

14.
BMC Public Health ; 16: 650, 2016 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-27464510

RESUMO

BACKGROUND: The Canadian Alliance for Healthy Hearts and Minds (CAHHM) is a pan-Canadian, prospective, multi-ethnic cohort study being conducted in Canada. The overarching objective of the CAHHM is to understand the association of socio-environmental and contextual factors (such as societal structure, activity, nutrition, social and tobacco environments, and access to health services) with cardiovascular risk factors, subclinical vascular disease, and cardiovascular and other chronic disease outcomes. METHODS/DESIGN: Participants between 35 and 69 years of age are being recruited from existing cohorts and a new First Nations Cohort to undergo a detailed assessment of health behaviours (including diet and physical activity), cognitive function, assessment of their local home and workplace environments, and their health services access and utilization. Physical measures including weight, height, waist/hip circumference, body fat percentage, and blood pressure are collected. In addition, eligible participants undergo magnetic resonance imaging (MRI) of the brain, heart, carotid artery and abdomen to detect early subclinical vascular disease and ectopic fat deposition. DISCUSSION: CAHHM is a prospective cohort study designed to investigate the impact of community level factors, individual health behaviours, and access to health services, on cognitive function, subclinical vascular disease, fat distribution, and the development of chronic diseases among adults living in Canada.


Assuntos
Doenças Cardiovasculares/etiologia , Acessibilidade aos Serviços de Saúde/estatística & dados numéricos , Avaliação de Resultados em Cuidados de Saúde/métodos , Aceitação pelo Paciente de Cuidados de Saúde/estatística & dados numéricos , Adulto , Idoso , Pressão Sanguínea , Determinação da Pressão Arterial , Tamanho Corporal , Canadá , Doença Crônica , Protocolos Clínicos , Cognição , Feminino , Comportamentos Relacionados com a Saúde , Humanos , Masculino , Pessoa de Meia-Idade , Estado Nutricional , Estudos Prospectivos , Características de Residência , Fatores de Risco
15.
Curr Cardiol Rep ; 18(9): 89, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27448403

RESUMO

Non-invasive external magnetic resonance imaging (MRI) of large vessel atherosclerosis is a robust and promising imaging modality that can be applied for the evaluation of the atherosclerotic process in large vessels. However, it requires expertise for setup and time for data acquisition and analysis. Intravascular MRI is a promising tool, but its use remains at the pre-clinical stage within selected research groups. In this review, the current status and future role of intravascular MRI for atherosclerotic plaque characterization are summarized, along with important challenges which will be necessary to overcome prior to the wide adoption of this technique.


Assuntos
Procedimentos Endovasculares/métodos , Angiografia por Ressonância Magnética/métodos , Placa Aterosclerótica/diagnóstico por imagem , Procedimentos Endovasculares/tendências , Humanos , Artéria Ilíaca/diagnóstico por imagem , Angiografia por Ressonância Magnética/tendências
16.
J Acoust Soc Am ; 139(4): 1691, 2016 04.
Artigo em Inglês | MEDLINE | ID: mdl-27106315

RESUMO

This paper describes the use of an ultrasonic imaging technique (Locadiff) for the Non-Destructive Testing & Evaluation of a concrete structure. By combining coda wave interferometry and a sensitivity kernel for diffuse waves, Locadiff can monitor the elastic and structural properties of a heterogeneous material with a high sensitivity, and can map changes of these properties over time when a perturbation occurs in the bulk of the material. The applicability of the technique to life-size concrete structures is demonstrated through the monitoring of a 15-ton reinforced concrete beam subject to a four-point bending test causing cracking. The experimental results show that Locadiff achieved to (1) detect and locate the cracking zones in the core of the concrete beam at an early stage by mapping the changes in the concrete's micro-structure; (2) monitor the internal stress level in both temporal and spatial domains by mapping the variation in velocity caused by the acousto-elastic effect. The mechanical behavior of the concrete structure is also studied using conventional techniques such as acoustic emission, vibrating wire extensometers, and digital image correlation. The performances of the Locadiff technique in the detection of early stage cracking are assessed and discussed.

17.
J Acoust Soc Am ; 137(2): 660-7, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25698001

RESUMO

This study focuses on imaging local changes in heterogeneous media. The method employed is demonstrated and validated using numerical experiments of acoustic wave propagation in a multiple scattering medium. Changes are simulated by adding new scatterers of different sizes at various positions in the medium, and the induced decorrelation of the diffuse (coda) waveforms is measured for different pairs of sensors. The spatial and temporal dependences of the decorrelation are modeled through a diffuse sensitivity kernel, based on the intensity transport in the medium. The inverse problem is then solved with a linear least square algorithm, which leads to a map of scattering cross section density of the changes.

18.
J Acoust Soc Am ; 138(1): 232-41, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26233022

RESUMO

This paper describes an original imaging technique, named Locadiff, that benefits from the diffuse effect of ultrasound waves in concrete to detect and locate mechanical changes associated with the opening of pre-existing cracks, and/or to the development of diffuse damage at the tip of the crack. After giving a brief overview of the theoretical model to describe the decorrelation of diffuse waveforms induced by a local change, the article introduces the inversion procedure that produces the three dimensional maps of density of changes. These maps are interpreted in terms of mechanical changes, fracture opening, and damage development. In addition, each fracture is characterized by its effective scattering cross section.

19.
J Cardiovasc Magn Reson ; 16: 3960, 2014 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-25551695

RESUMO

We propose a set of simplified terms to describe applied Cardiovascular Magnetic Resonance (CMR) pulse sequence techniques in clinical reports, scientific articles and societal guidelines or recommendations. Rather than using various technical details in clinical reports, the description of the technical approach should be based on the purpose of the pulse sequence. In scientific papers or other technical work, this should be followed by a more detailed description of the pulse sequence and settings. The use of a unified set of widely understood terms would facilitate the communication between referring physicians and CMR readers by increasing the clarity of CMR reports and thus improve overall patient care. Applied in research articles, its use would facilitate non-expert readers' understanding of the methodology used and its clinical meaning.


Assuntos
Doenças Cardiovasculares/diagnóstico , Imageamento por Ressonância Magnética/classificação , Terminologia como Assunto , Doenças Cardiovasculares/patologia , Doenças Cardiovasculares/fisiopatologia , Compreensão , Consenso , Humanos , Valor Preditivo dos Testes
20.
Cardiovasc Ultrasound ; 12: 14, 2014 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-24708546

RESUMO

BACKGROUND: Studies assessing ischemic mitral regurgitation (IMR) comprised of heterogeneous population and evaluated IMR in the subacute setting. The incidence of early IMR in the setting of primary PCI, its progression and clinical impact over time is still undetermined. We sought to determine the predictors and prognosis of early IMR after primary percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction (STEMI). METHODS: Using our primary PCI database, we screened for patients who underwent ≥2 transthoracic echocardiograms early (1-3 days) and late (1 year) following primary PCI. The primary outcomes were: (1) major adverse events (MACE) including death, ischemic events, repeat hospitalization, re-vascularization and mitral repair or replacement (2) changes in quantitative echocardiographic assessments. RESULTS: From January 2006 to July 2012, we included 174 patients. Post-primary PCI IMR was absent in 95 patients (55%), mild in 60 (34%), and moderate to severe in 19 (11%). Early after primary PCI, IMR was independently predicted by an ischemic time > 540 min (OR: 2.92 [95% CI, 1.28 - 7.05]; p = 0.01), and female gender (OR: 3.06 [95% CI, 1.42 - 6.89]; p = 0.004). At a median follow-up of 366 days [34-582 days], IMR was documented in 44% of the entire cohort, with moderate to severe IMR accounting for 15%. During follow-up, MR regression (change ≥ 1 grade) was seen in 18% of patients. Moderate to severe IMR remained an independent predictor of MACE (HR: 2.58 [95% CI, 1.08 - 5.53]; p = 0.04). CONCLUSIONS: After primary PCI, IMR is a frequent finding. Regression of early IMR during long-term follow-up is uncommon. Since moderate to severe IMR post-primary PCI appears to be correlated with worse outcomes, close follow-up is required.


Assuntos
Doença da Artéria Coronariana/terapia , Ecocardiografia/métodos , Insuficiência da Valva Mitral/diagnóstico por imagem , Insuficiência da Valva Mitral/mortalidade , Infarto do Miocárdio/terapia , Intervenção Coronária Percutânea , Idoso , Ponte de Artéria Coronária , Doença da Artéria Coronariana/mortalidade , Doença da Artéria Coronariana/cirurgia , Bases de Dados Factuais , Diagnóstico Precoce , Feminino , Seguimentos , Insuficiência Cardíaca/diagnóstico por imagem , Insuficiência Cardíaca/mortalidade , Insuficiência Cardíaca/cirurgia , Implante de Prótese de Valva Cardíaca , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Insuficiência da Valva Mitral/cirurgia , Infarto do Miocárdio/mortalidade , Infarto do Miocárdio/cirurgia , Valor Preditivo dos Testes , Prognóstico , Resultado do Tratamento
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