Glomerular hemodynamics and arterial function in normal individuals.

Objective To determine the relationship between arterial function (stiffness and wave reflection) and glomerular hemodynamics. Methods In 49 healthy normotensive individuals, glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) were measured by urinary clearances of 99m TC-DTPA and 131 I-hippuran, respectively. Filtration fraction was computed as GFR/ERPF. Arterial stiffness was estimated by carotid-femoral pulse wave velocity (PWV). Wave reflection was evaluated by carotid augmentation index (Alx), reflection magnitude and the round-trip travel time of the pressure wave. Results PWV and round-trip travel time were not independently correlated with any renal hemodynamic parameter or urinary albumin-creatinine ratio (UACR). Alx and reflection magnitude were directly correlated with filtration fraction (r=0.35 and 0.37, respectively) and UACR (r= 0 . 43 and 0.53, respectively). When the population was divided into quartiles of reflection magnitude, filtration fraction and UACR progressively increased from the lowest to the highest quartile and after adjustment for age, mean arterial pressure, heart rate but also sex for UACR (P linear trend = 0.031 and 0.001, respectively). Conclusion It is suggested that in normal individuals, the amplitude of wave reflection but not arterial stiffness is associated with signs evocative of increased glomerular pressure (filtration fraction and UACR), independently of systemic blood pressure.