Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 9 de 9
Filtrar
Mais filtros











Base de dados
Intervalo de ano de publicação
2.
J Hypertens ; 37(12): 2481-2489, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31268872

RESUMO

OBJECTIVES: Previous studies have demonstrated that high-dose allopurinol is able to regress left ventricular (LV) mass in cohorts with established cardiovascular disease. The aim of this study was to assess whether treatment with high-dose allopurinol would regress LV mass in a cohort with essential hypertension, LV hypertrophy and well-controlled blood pressure but without established cardiovascular disease. METHODS: We conducted a mechanistic proof-of-concept randomized, placebo-controlled, double-blind trial of allopurinol (600 mg/day) versus placebo on LV mass regression. Duration of treatment was 12 months. LV mass regression was assessed by Cardiac Magnetic Resonance. Secondary outcomes were changes in endothelial function (flow-mediated dilatation), arterial stiffness (pulse wave velocity) and biomarkers of oxidative stress. RESULTS: Seventy-two patients were randomized into the trial. Mean baseline urate was 362.2 ±â€Š96.7 µmol/l. Despite good blood pressure control, LV mass regression was significantly reduced in the allopurinol cohort compared with placebo (LV mass -0.37 ±â€Š6.08 versus -3.75 ±â€Š3.89 g; P = 0.012). Oxidative stress markers (thiobarbituric acid reactive substances) were significantly higher in the allopurinol group versus placebo (0.26 ±â€Š0.85 versus -0.34 ±â€Š0.83 µmol/l; P = 0.007). Other markers of vascular function were not significantly different between the two groups. CONCLUSION: Treatment with high-dose allopurinol in normouricemic controlled hypertensive patients and LV hypertrophy is detrimental. It results in reduced LV mass regression and increased oxidative stress over a 12-month period. This may be because of an adverse impact on redox balance. Cohort selection for future cardiovascular trials with allopurinol is crucial.


Assuntos
Alopurinol/efeitos adversos , Hipertensão Essencial , Ventrículos do Coração , Hipertrofia Ventricular Esquerda , Alopurinol/farmacologia , Alopurinol/uso terapêutico , Pressão Sanguínea/efeitos dos fármacos , Método Duplo-Cego , Hipertensão Essencial/complicações , Ventrículos do Coração/efeitos dos fármacos , Ventrículos do Coração/fisiopatologia , Humanos , Hipertrofia Ventricular Esquerda/complicações , Hipertrofia Ventricular Esquerda/tratamento farmacológico , Estresse Oxidativo/efeitos dos fármacos , Análise de Onda de Pulso
3.
Radiology ; 287(3): 795-804, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29714681

RESUMO

Purpose To quantify the burden and distribution of asymptomatic atherosclerosis in a population with a low to intermediate risk of cardiovascular disease. Materials and Methods Between June 2008 and February 2013, 1528 participants with 10-year risk of cardiovascular disease less than 20% were prospectively enrolled. They underwent whole-body magnetic resonance (MR) angiography at 3.0 T by using a two-injection, four-station acquisition technique. Thirty-one arterial segments were scored according to maximum stenosis. Scores were summed and normalized for the number of assessable arterial segments to provide a standardized atheroma score (SAS). Multiple linear regression was performed to assess effects of risk factors on atheroma burden. Results A total of 1513 participants (577 [37.9%] men; median age, 53.5 years; range, 40-83 years) completed the study protocol. Among 46 903 potentially analyzable segments, 46 601 (99.4%) were interpretable. Among these, 2468 segments (5%) demonstrated stenoses, of which 1649 (3.5%) showed stenosis less than 50% and 484 (1.0%) showed stenosis greater than or equal to 50%. Vascular stenoses were distributed throughout the body with no localized distribution. Seven hundred forty-seven (49.4%) participants had at least one stenotic vessel, and 408 (27.0%) participants had multiple stenotic vessels. At multivariable linear regression, SAS correlated with age (B = 3.4; 95% confidence interval: 2.61, 4.20), heart rate (B = 1.23; 95% confidence interval: 0.51, 1.95), systolic blood pressure (B = 0.02; 95% confidence interval: 0.01, 0.03), smoking status (B = 0.79; 95% confidence interval: 0.44, 1.15), and socioeconomic status (B = -0.06; 95% confidence interval: -0.10, -0.02) (P < .01 for all). Conclusion Whole-body MR angiography identifies early vascular disease at a population level. Although disease prevalence is low on a per-vessel level, vascular disease is common on a per-participant level, even in this low- to intermediate-risk cohort. © RSNA, 2018 Online supplemental material is available for this article.


Assuntos
Aterosclerose/diagnóstico por imagem , Aterosclerose/epidemiologia , Angiografia por Ressonância Magnética/métodos , Imagem Corporal Total/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Meios de Contraste , Feminino , Humanos , Aumento da Imagem/métodos , Masculino , Pessoa de Meia-Idade , Prevalência , Estudos Prospectivos , Risco , Escócia/epidemiologia
4.
J Magn Reson Imaging ; 44(5): 1186-1196, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27143317

RESUMO

PURPOSE: To scan a volunteer population using 3.0T magnetic resonance imaging (MRI). MRI of the left ventricular (LV) structure and function in healthy volunteers has been reported extensively at 1.5T. MATERIALS AND METHODS: A population of 1528 volunteers was scanned. A standardized approach was taken to acquire steady-state free precession (SSFP) LV data in the short-axis plane, and images were quantified using commercial software. Six observers undertook the segmentation analysis. RESULTS: Mean values (±standard deviation, SD) were: ejection fraction (EF) = 69 ± 6%, end diastolic volume index (EDVI) = 71 ± 13 ml/m2 , end systolic volume index (ESVI) = 22 ± 7 ml/m2 , stroke volume index (SVI) = 49 ± 8 ml/m2 , and LV mass index (LVMI) = 55 ± 12 g/m2 . The mean EF was slightly larger for females (69%) than for males (68%), but all other variables were smaller for females (EDVI 68v77 ml/m2 , ESVI 21v25 ml/m2 , SVI 46v52 ml/m2 , LVMI 49v64 g/m2 , all P < 0.05). The mean LV volume data mostly decreased with each age decade (EDVI males: -2.9 ± 1.3 ml/m2 , females: -3.1 ± 0.8 ml/m2 ; ESVI males: -1.3 ± 0.7 ml/m2 , females: -1.7 ± 0.5 ml/m2 ; SVI males: -1.7 ± 0.9 ml/m2 , females: -1.4 ± 0.6 ml/m2 ; LVMI males: -1.6 ± 1.1 g/m2 , females: -0.2 ± 0.6 g/m2 ) but the mean EF was virtually stable in males (0.6 ± 0.6%) and rose slightly in females (1.2 ± 0.5%) with age. CONCLUSION: LV reference ranges are provided in this population-based MR study at 3.0T. The variables are similar to those described at 1.5T, including variations with age and gender. These data may help to support future population-based MR research studies that involve the use of 3.0T MRI scanners. J. Magn. Reson. Imaging 2016;44:1186-1196.


Assuntos
Envelhecimento/patologia , Envelhecimento/fisiologia , Ventrículos do Coração/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Volume Sistólico/fisiologia , Função Ventricular Esquerda/fisiologia , Adulto , Distribuição por Idade , Idoso , Idoso de 80 Anos ou mais , Feminino , Ventrículos do Coração/anatomia & histologia , Humanos , Imageamento por Ressonância Magnética/estatística & dados numéricos , Masculino , Programas de Rastreamento , Pessoa de Meia-Idade , Valores de Referência , Distribuição por Sexo , Fatores Sexuais , Reino Unido/epidemiologia
5.
BMC Med Imaging ; 16: 18, 2016 Feb 29.
Artigo em Inglês | MEDLINE | ID: mdl-26923316

RESUMO

BACKGROUND: The aim of this study was to use whole body cardiovascular magnetic resonance imaging (WB CVMR) to assess the heart and arterial network in a single examination, so as to describe the burden of atherosclerosis and subclinical disease in participants with symptomatic single site vascular disease. METHODS: 64 patients with a history of symptomatic single site vascular disease (38 coronary artery disease (CAD), 9 cerebrovascular disease, 17 peripheral arterial disease (PAD)) underwent whole body angiogram and cardiac MR in a 3 T scanner. The arterial tree was subdivided into 31 segments and each scored according to the degree of stenosis. From this a standardised atheroma score (SAS) was calculated. Cine and late gadolinium enhancement images of the left ventricle were obtained. RESULTS: Asymptomatic atherosclerotic disease with greater than 50% stenosis in arteries other than that responsible for their presenting complain was detected in 37% of CAD, 33% of cerebrovascular and 47% of PAD patients. Unrecognised myocardial infarcts were observed in 29% of PAD patients. SAS was significantly higher in PAD patients 24 (17.5-30.5) compared to CAD 4 (2-11.25) or cerebrovascular disease patients 6 (2-10) (ANCOVA p < 0.001). Standardised atheroma score positively correlated with age (ß 0.36 p = 0.002), smoking status (ß 0.34 p = 0.002), and LV mass (ß -0.61 p = 0.001) on multiple linear regression. CONCLUSION: WB CVMR is an effective method for the stratification of cardiovascular disease. The high prevalence of asymptomatic arterial disease, and silent myocardial infarctions, particularly in the peripheral arterial disease group, demonstrates the importance of a systematic approach to the assessment of cardiovascular disease.


Assuntos
Aterosclerose/diagnóstico , Doenças Cardiovasculares/complicações , Imageamento por Ressonância Magnética/métodos , Imagem Corporal Total/métodos , Fatores Etários , Idoso , Aterosclerose/epidemiologia , Doenças Cardiovasculares/diagnóstico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Análise de Regressão , Fatores de Risco
6.
J Am Coll Cardiol ; 62(24): 2284-93, 2013 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-23994420

RESUMO

OBJECTIVES: This study sought to ascertain whether high-dose allopurinol causes regression of left ventricular mass (LVM) in patients with type 2 diabetes mellitus (T2DM). BACKGROUND: Left ventricular hypertrophy (LVH) is common in T2DM and contributes to patients' high cardiovascular (CV) event rate. Oxidative stress (OS) has been implicated in LVH development, and allopurinol has been previously shown to reduce vascular OS. We therefore investigated whether allopurinol causes regression of LVH in patients with T2DM. METHODS: We conducted a randomized, double-blind, placebo-controlled study of 66 optimally-treated T2DM patients with echocardiographic evidence of LVH. Allopurinol, 600 mg/day, or placebo was given over the study period of 9 months. The primary outcome was reduction in LVM as calculated by cardiac magnetic resonance imaging at baseline and at 9 months' follow-up. Secondary endpoints were change in flow-mediated dilation and augmentation index. RESULTS: Allopurinol significantly reduced absolute LVM (-2.65 ± 5.91 g vs. placebo group +1.21 ± 5.10 g [p = 0.012]) and LVM indexed to body surface area (-1.32 ± 2.84 g/m(2) vs. placebo group +0.65 ± 3.07 g/m(2) [p = 0.017]). No significant changes were seen in either flow-mediated dilation or augmentation index. CONCLUSIONS: Allopurinol causes regression of LVM in patients with T2DM and LVH. Regression of LVH has been shown previously to improve CV mortality and morbidity. Therefore, allopurinol therapy may become useful to reduce CV events in T2DM patients with LVH. (Allopurinol in Patients with Diabetes and LVH; UKCRN 8766).


Assuntos
Alopurinol/administração & dosagem , Diabetes Mellitus Tipo 2/complicações , Hipertrofia Ventricular Esquerda/tratamento farmacológico , Idoso , Análise de Variância , Método Duplo-Cego , Feminino , Ventrículos do Coração/patologia , Humanos , Hipertrofia Ventricular Esquerda/complicações , Imagem Cinética por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Ácido Úrico/sangue
7.
Clin Endocrinol (Oxf) ; 79(4): 484-90, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23469866

RESUMO

OBJECTIVE: The significant role of corticosteroids in hypertension and cardiovascular disease highlights the importance of the adrenal gland in these disorders. The ability to correlate corticosteroid production with adrenal volume offers a novel research tool and intermediate phenotype in cardiovascular disease. The aim of this study was to develop and validate the use of magnetic resonance imaging (MRI) in adrenal volume assessment and investigate whether this associates with corticosteroid production. DESIGN/METHODS: Twenty normotensive men underwent noncontrast 1·5T MRI scanning of adrenals, measurement of blood pressure and plasma corticosteroids. Left adrenal volume was calculated twice using standard segmentation software by four independent observers with differing levels of clinical expertise and segmentation experience. To optimize this process, adrenal 'phantoms' with known fixed volumes underwent MRI scanning and analysis by two observers. RESULTS: Intra-observer coefficients of repeatability (CoRs) in phantoms ranged from 0·23 to 0·43 ml (interobserver CoR 0·48 ml). In the subject group, mean adrenal volumes were 3·99-5·82 ml with intra-observer CoRs 0·27-1·94 ml. Interobserver variability was 2·73 ml. Segmentation expertise was the main factor affecting variability, with experienced observers having the lowest CoRs; clinical knowledge was a factor when combined with segmentation experience. Mean adrenal volume correlated with plasma glucocorticoids (r = 0·523, P < 0·05) and aldosterone (r = 0·515, P < 0·05) for the most experienced observer only. CONCLUSIONS: Measurement of adrenal volume using MRI is challenging; most accurate volumes are achieved using a single observer with both segmentation experience and anatomical knowledge. The data also provide novel preliminary evidence that adrenal gland volume may be associated with plasma corticosteroid concentrations supporting further study of adrenal volume and steroid production across a range of blood pressures.


Assuntos
Corticosteroides/sangue , Glândulas Suprarrenais/anatomia & histologia , Pressão Sanguínea/fisiologia , Imageamento por Ressonância Magnética/métodos , Adulto , Voluntários Saudáveis , Humanos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Variações Dependentes do Observador , Projetos Piloto , Análise de Regressão , Reprodutibilidade dos Testes
8.
J Am Coll Cardiol ; 61(9): 926-32, 2013 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-23449426

RESUMO

OBJECTIVES: This study sought to ascertain if high-dose allopurinol regresses left ventricular mass (LVM) in patients with ischemic heart disease (IHD). BACKGROUND: LV hypertrophy (LVH) is common in patients with IHD including normotensive patients. Allopurinol, a xanthine oxidase inhibitor, has been shown to reduce LV afterload in IHD and may therefore also regress LVH. METHODS: A randomized, double-blind, placebo-controlled, parallel group study was conducted in 66 patients with IHD and LVH, comparing 600 mg/day allopurinol versus placebo therapy for 9 months. The primary outcome measure was change in LVM, assessed by cardiac magnetic resonance imaging (CMR). Secondary outcome measures were changes in LV volumes by CMR, changes in endothelial function by flow-mediated dilation (FMD), and arterial stiffness by applanation tonometry. RESULTS: Compared to placebo, allopurinol significantly reduced LVM (allopurinol -5.2 ± 5.8 g vs. placebo -1.3 ± 4.48 g; p = 0.007) and LVM index (LVMI) (allopurinol -2.2 ± 2.78 g/m(2) vs. placebo -0.53 ± 2.5 g/m(2); p = 0.023). The absolute mean difference between groups for change in LVM and LVMI was -3.89 g (95% confidence interval: -1.1 to -6.7) and -1.67 g/m(2) (95% confidence interval: -0.23 to -3.1), respectively. Allopurinol also reduced LV end-systolic volume (allopurinol -2.81 ± 7.8 mls vs. placebo +1.3 ± 7.22 mls; p = 0.047), improved FMD (allopurinol +0.82 ± 1.8% vs. placebo -0.69 ± 2.8%; p = 0.017) and augmentation index (allopurinol -2.8 ± 5.1% vs. placebo +0.9 ± 7%; p = 0.02). CONCLUSIONS: High-dose allopurinol regresses LVH, reduces LV end-systolic volume, and improves endothelial function in patients with IHD and LVH. This raises the possibility that allopurinol might reduce future cardiovascular events and mortality in these patients. (Does a Drug Allopurinol Reduce Heart Muscle Mass and Improve Blood Vessel Function in Patients With Normal Blood Pressure and Stable Angina?; ISRCTN73579730).


Assuntos
Alopurinol/administração & dosagem , Hipertrofia Ventricular Esquerda/tratamento farmacológico , Isquemia Miocárdica/complicações , Idoso , Método Duplo-Cego , Feminino , Humanos , Hipertrofia Ventricular Esquerda/diagnóstico , Hipertrofia Ventricular Esquerda/etiologia , Imageamento por Ressonância Magnética , Masculino , Manometria
9.
J Am Soc Nephrol ; 22(7): 1382-9, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21719783

RESUMO

Allopurinol ameliorates endothelial dysfunction and arterial stiffness among patients without chronic kidney disease (CKD), but it is unknown if it has similar effects among patients with CKD. Furthermore, because arterial stiffness increases left ventricular afterload, any allopurinol-induced improvement in arterial compliance might also regress left ventricular hypertrophy (LVH). We conducted a randomized, double-blind, placebo-controlled, parallel-group study in patients with stage 3 CKD and LVH. We randomly assigned 67 subjects to allopurinol at 300 mg/d or placebo for 9 months; 53 patients completed the study. We measured left ventricular mass index (LVMI) with cardiac magnetic resonance imaging (MRI), assessed endothelial function by flow-mediated dilation (FMD) of the brachial artery, and evaluated central arterial stiffness by pulse-wave analysis. Allopurinol significantly reduced LVH (P=0.036), improved endothelial function (P=0.009), and improved the central augmentation index (P=0.015). This study demonstrates that allopurinol can regress left ventricular mass and improve endothelial function among patients with CKD. Because LVH and endothelial dysfunction associate with prognosis, these results call for further trials to examine whether allopurinol reduces cardiovascular events in patients with CKD and LVH.


Assuntos
Alopurinol/uso terapêutico , Antimetabólitos/uso terapêutico , Endotélio Vascular/efeitos dos fármacos , Hipertrofia Ventricular Esquerda/tratamento farmacológico , Insuficiência Renal Crônica/complicações , Idoso , Alopurinol/farmacologia , Antimetabólitos/farmacologia , Método Duplo-Cego , Feminino , Humanos , Hipertrofia Ventricular Esquerda/complicações , Masculino , Pessoa de Meia-Idade , Insuficiência Renal Crônica/tratamento farmacológico , Xantina Oxidase/antagonistas & inibidores
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA