Ο προγνωστικός ρόλος των λειτουργικών εφεδρείων νεφρού στην εξέλιξη του ρυθμού σπειραματικής διήθησης σε ασθενείς με ιδιοπαθή υπέρταση ; The predictive role of renal functional reserve in the progression of glomerular filtration rate in patients with essential hypertension

Objective: Renal Functional Reserve (RFR) has been considered as a promising tool for the diagnosis of early nephron loss and functional renal mass. A reduced RFR has been demonstrated by some studies in early stages of arterial hypertension, attributed mainly to impaired vasodilator responsiveness and with the overactivity of the sympathetic nervous system (SNS) considered as one of the candidates involved mechanisms. In the present study we aimed to assess 1) whether RFR plays a prognostic role in the progression of eGFR in healthy and hypertensive patients with preserved renal function and 2) any associations of RFR with the hemodynamic load, inotropic capacity of the heart and asymptomatic end-organ damage in hypertensives with eGFR≥60 ml/min/1.73m2.Design and Methods: In a 24-month prospective and interventional study, 51 newly diagnosed essential hypertensives (age 53.2±12.1 years, 54% men) and 20 healthy normotensives (age 54.3±10.0 years, 45% men) with eGFR≥60 ml/min/1.73m2 who met the study’s entry criteria were followed. Participants initially underwent laboratory and paraclinical testing to rule out secondary hypertension as well as office blood pressure (BP) and 24h ambulatory BP measurements (ABPM). Hypertensives were additionally screened for asymptomatic target organ damage with echocardiographic study to assess left ventricular mass index (LVMI) and with measurements of pulse wave velocity (PWV). In addition, they underwent a treadmill test to control the inotropic response. In all participants, RFR was determined by endogenous creatinine clearance and by using cooked meal as protein load (1.2gr/kg). Normal RFR was defined as RFR≥30ml/min. Afterwards, antihypertensive treatment with valsartan was started and the doses were titrared according to office BP at subsequent visits. To calculate the annual and two-year change in eGFR, serum creatinine (Scr) was determined in all participants at months 12 and 24 respectively.Results: Demographic characteristics and markers of renal function (Scr, eGFR, ...