Evaluation of acute partial unilateral ureteral obstruction based on the renal venous impedance index in Rabbit: An experimental study

To investigate the feasibility of the venous impedance index (VII) in the diagnosis of acute partial unilateral ureteral obstruction (APUUO), in this study we aimed to measure and compare changes in intrarenal venous flow and arterial flow. In New Zealand rabbits (n=10) the left ureter was narrowed by ligation. Doppler ultrasonographic (US) examination of the interlobar arteries and veins in both kidneys was performed preoperatively and 3, 6, 12, 24, and 48 h after ureteral ligation. Resistive index (RI), RI difference (RIA) and the RI ratio (RIr), and the VII difference (VIIA) were calculated from RI and VII obtained from the obstructive and nonobstructive kidneys. The RI and VII were postoperatively compared between the left and right kidneys. Although the mean RI for obstructive kidneys was higher than those for nonobstructive kidneys, the difference was only statistically significant at 3 and 24 h (P=0.007, and P=0.049, respectively). In all postoperative measurement times, RIA was 0.002), and the VIIA was equal to or greather than 0.159. The venous flow was more affected than arterial flow in the obstructive kidney. The renal RI alone was insufficient as a diagnostic criterion. The renal VIIA 0.16 can be enhanced the diagnostic accuracy of in APUUO if used as a combination of the RIA>0.08 and RIr>1.1.