ABSTRACTTo evaluate the possibility that the placement of arteriovenous anastomosis (a/v a) may lead to the attenuation of glomerular hyperfiltration, we studied 5 nondiabetic patients before and after creation of vascular access for hemodialysis. Patients received no EPO and antihypertensive therapy was discontinued 24 h before each study. Cardiac output (CO) and a/v a flow rates were measured by Doppler echo, and GFR and ERPF by plasma decay curves of TC99m DTPA and131l-hippuran, respectively. Other parameters were calculated by standard formulas. Augmentation of CO and decrease in systemic vascular resistance occurred in all patients (p = 0.05), yet renal findings were less predictable since only three patients showed a decrease in renal vascular resistance and filtration fraction post a/v a. Thus, there is a discordant pattern of renal hemodynamic response to the creation of a/v a in end-stage renal disease and further studies are needed to better define the subset of patients who are prone to renal vasodilation after the placement of a/v a.