RESUMO
The authors evaluated endothelial function in patients with MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke) by flow-mediated vasodilation (FMD) and found a significant decrease vs controls. Two years of supplementation with oral l-arginine, a nitric oxide precursor, significantly improved endothelial function to control levels and was harmonized with the normalized plasma levels of l-arginine in patients. l-Arginine therapy improved endothelial dysfunction and showed promise in treating strokelike episodes in MELAS.
Assuntos
Arginina/administração & dosagem , Circulação Cerebrovascular/efeitos dos fármacos , Endotélio Vascular/efeitos dos fármacos , Síndrome MELAS/tratamento farmacológico , Acidente Vascular Cerebral/prevenção & controle , Administração Oral , Adolescente , Adulto , Velocidade do Fluxo Sanguíneo/efeitos dos fármacos , Criança , Suplementos Nutricionais , Feminino , Humanos , Síndrome MELAS/diagnóstico , Masculino , Pessoa de Meia-Idade , Acidente Vascular Cerebral/diagnóstico , Vasodilatadores/administração & dosagemRESUMO
Although the assessment of right ventricular (RV) function is important in the clinical management of children with congenital heart disease, available imaging techniques have been limited because of the complex geometry of the right ventricle. A new Doppler index combining systolic and diastolic time intervals (the Tei index) has been reported to be useful for the assessment of global RV function in adults. However, normal values in children, age-related changes, and the clinical utility of the Tei index with regard to congenital heart disease have not been demonstrated. The purpose of this study was to prospectively assess RV function in children with normal heart and congenital heart disease using the Tei index. The subjects included 150 healthy children and 43 patients with congenital heart disease (35 patients with atrial septal defects and 8 patients who had had a Senning operation). The index was defined as the sum of isovolumetric contraction time and isovolumetric relaxation time divided by ejection time and was measured from conventional RV outflow and inflow Doppler velocity profiles. The Tei index was not affected by age in healthy children (0.24 +/- 0.04). There was a significant difference in index rating between patients who had had a Senning operation (0.58 +/- 0.09) and healthy children (p < 0.01), but there was no significant difference between children with atrial septal defect (0.25 +/- 0.13) and healthy children. The Tei index is a feasible approach to use when assessing global RV function in children with congenital heart disease.