ABSTRACT
Antecedentes: el déficit de estrógenos propio de la etapa postmenopáusica, puede contribuir al desarrollo de un disbalance autonómico con la reducción del reflejo cardiovagal, lo que a su vez puede incrementar el riesgo cardiovascular. Aún no se han aclarado en su totalidad los mecanismos fisiopatológicos subyacentes de esta alteración. En este artículo se discute el efecto de la terapia hormonal de reemplazo sobre la función autonómica en mujeres sometidas a histerectomía.Métodos: en este ensayo clínico cruzado, placebo-controlado, doble ciego, se incluyeron mujeres con histerectomía y amenorrea al menos un año antes de la cirugía. De forma aleatoria, recibieron estrógenos conjugados 0,625 mg/dL o placebo durante doce semanas, con un período intermedio sin medicación de dos semanas. Se evaluó la función autonómica cardiovagal y vascular mediante técnicas convencionales y a tráves de pletismografía por oclusión venosa para calcular el flujo sanguíneo en el antebrazo y la resistencia vascular periférica en condiciones basales, durante la prueba de mesa basculante y en la prueba de presión negativa en miembros inferiores...
Background: estrogen deficit during menopause may be related to cardiac autonomic function imbalance, reducing the cardiovagal reflex response that could potentially increase cardiovascular risk. The physiological mechanisms that lead to this alteration in postmenopausal women remain unclear. In this article, the effect of hormonal replacement therapy on autonomic function in women submitted to hysterectomy is discussed.Methods: Fifty women with a previous hysterectomy and amenorrhea for 1 year prior to surgery were enrolled in a prospective randomized crossover double-blind placebo controlled trial. Either oral estrogen replacement therapy (ERT) conjugated estrogens 0.625 mg once a day or placebo, were randomly administered in a crossover design during 12 weeks with a 2 week washout period. Cardiovagal autonomic function was assessed by conventional techniques and through venous occlusion plethysmography in order to evaluate vascular autonomic function calculating forearm blood flow (FBF) and peripheral vascular resistance (PVR) at baseline, and during head-up tilt (HUT) and a non-hypotensive stimuli (-10mmHg) lower-body negative pressure (LBNP).Results: No differences were found in cardiovagal autonomic function comparing ERT vs. placebo at baseline resting conditions, nor during HUT and LBNP. A significant difference was identified in supine FBF [1.9(0.5) vs. 1.5(0.5), p=0.02] as well as in PVR [53.5(18.2) vs. 68.6(34), p=0.02] comparing ERT vs. placebo interventions.Conclusions: Short term ERT did not improve cardiovascular autonomic reflex responses in postmenopausal women, but increased vascular relaxation primarily by reducing peripheral vascular resistance. Hormone replacement therapy can be used under adequate supervision in order to improve menopausal symptoms during a short period of time, mainly in young non-hypertensive post-menopausal women.