Hemodynamic responses of 0.9% saline solution infusion in obese resistant hypertensive patients

Abstract

Resistant hypertension (RH) is defined as the condition whose the blood pressure (BP) pressure remains above the target despite the concurrent use of three or more classes of antihypertensive drugs in optimal doses, and if possible a diuretic. The mechanisms of resistance to antihypertensive treatment are not fully elucidated, and may be modulated by several related factors such as obesity, hyperactivation of the sympathetic nervous and the renin-angiotensin-aldosterone systems, volume expansion and increased peripheral vascular resistance (PVR). This project aims to assess whether acute infusion of 0.9% saline solution modulates the hemodynamic parameters such as mean BP, cardiac output and PVR as well as cardiovascular biomarkers in obese resistant hypertensive subjects. The study will include 10 patients in follow-up at the Outpatient Resistant Hypertension Clinic of Clinical Hospital/UNICAMP which will receive infusion of 250mL at 0.9% saline concentration for 2 hours. We will determine office BP, aldosterone, and plasma cortisol (performed by ELISA) in the pre- and post-infusion. Non-invasive hemodynamic parameters (Finometer system) will be determined simultaneously with the infusion. This study may contribute to a better understanding of the pathophysiological mechanisms related to drug resistance to antihypertensive drugs, mainly related to the prevalent characteristics, such as volume expansion and obesity, of this specific group of hypertensive subjects. (AU)