Evaluación ultrasonográfica de la función endotelial en niños y adultos chilenos / Ultrasound assessment of endothelial function in Chilean children and adults

Background: Endothelial dysfunction is an important pathogenetic mechanism in the development of atherosclerosis. Aim: To evaluate endothelial function in Chilean children and adult subjects and to provide normal values of flow mediated dilatation (FMD) in the Chilean population. Subjects and Methods: Flow mediated dilation of the brachial artery was measured by high resolution ultrasonography in healthy children (n=32) and adults (n=69) of both gender, in a group of 8 healthy women during 4 periods of pregnancy and late postpartum, and in 22 men and women with a history of stroke or coronary heart disease. Results: FMD in boys and girls was 9.9±3.6 and 10.0±4.2% respectively (NS). The figures for young women and young men were 11.3±3.8 and 8.6±3.9, respectively (p=0.02); for postmenopausal women and older men, 5.5±6.6 and 7.6±6.7 respectively (NS). During normal pregnancy and postpartum there were no significant changes in FMD. Patients with cardiovascular disease had a FMD of 0.3±5.2%, (p <0.001, with other groups). Conclusions: The present study provides values of FMD in healthy Chilean subjects of different ages, and in patients with coronary heart disease.

¿Puede prevenirse la preeclampsia a través del reconocimiento de la disfunción endotelial primaria y de su manejo con L-Arginina?: ¿cómo ayuda el ultrasonido Doppler? / Can we prevent preeclampsia through the recognition of primary endothelial dysfunction and its handling with L-Arginina?: how does the Doppler ultrasound help?

Con la hipótesis de que la disfunción endotelial primaria representa un factor de riesgo manejable para patologías asociadas a defectos de placentación, como el aborto recurrente y la preeclampsia, se estudiaron 13 mujeres con abortos recurrentes, 16 mujeres con antecedentes de preeclampsia severa precoz, y se compararon con 12 mujeres que cursaron embarazos normales. El 39 por ciento de las mujeres con abortos recurrentes y el 44 por ciento de las mujeres con preeclampsia previa presentó disfunción endotelial severa, comparado con el 0 por ciento en mujeres controles (Chi2). La suplementación oral de L-Arginina (0.1 g/kg/día), por 2 semanas a 10 mujeres que mantuvieron resistencia de arterias uterinas elevada en gestaciones tempranas en dos evaluaciones utrasonográficas se asoció a una normalización en el índice de resistencia (0,89 ñ 0,02 a 0,79 ñ 0,03, p < 0,05), mientras que las mujeres que recibieron placebo mantuvieron un índice de resistencia elevado (0,93 ñ 0,01 a 0,86 ñ 0,02, n.s.). El suplemento de L-Arginina administrado a partir de la décima semana de gestación a 12 mujeres con desórdenes previos relacionados con la placentación se asoció a un buen resultados reproductivo. Estos apoyan la hipótesis que la disfución endotelial severa es una condición de base prevalente en pacientes que presentan preeclampsia severa previa o abortos recurrentes. Además, sugiere que en estas pacientes un aumento en la vía L-Arginina-NO a través del suplemento de L-Arginina en gestaciones precoces, podría mejorar la función endotelial, la resistencia vascular de arterias uterinas y el resultado perinatal

Disfunción endotelial como alteración primaria en las patologías vasculares / Endothelial dysfunction as a primary alteration in vascular diseases

Endothelium controls vascular smooth muscle tone by secreting relaxing and contracting factors. There is a constant release of endothelium derived relaxing factors, mainly nitric oxide, a potent vasodilator, inhibitor of platelet aggregation, monocyte adhesion and smooth muscle proliferation. In addition, the endothelium may increase the release of NO in response to humoral stimulation by vasoactive substances such as acetylcholine, bradikinin or substance P. Although the endothelium releases a number of products, no single blood test has yet proved useful to determine normal endothelial function or as early abnormalities. The most useful test of endothelial function relies on the meassurement of endothelium-dependent dilatation in response to pharmacological or physiologic stimuli. The alteration of this response is known as endothelial dysfunction and has been observed in a variety of circumstances related to cardiovascular risk. This review summarizes the evidence that sustains this association and emphasizes the clinical utility of assessing endothelial function presenting two clinical cases of hypercholesterolemia in which a high-resolution vascular ultrasound in the braquial artery was used