Evaluation of renal artery stenosis with hemodynamic parameters of Doppler sonography

Objective The purpose of this study was to determine the values of the hemodynamic parameters of Doppler sonography in the diagnosis of renal artery stenosis (RAS) (diameter reduction ≥50%) and to investigate their possible influencing factors. Methods Five Doppler parameters, including renal peak systolic velocity (RPSV), renal-aortic ratio (RAR), renal-renal ratio (RRR), renal-segmental ratio (RSR), and renal-interlobar ratio (RIR), were measured in 81 patients before arteriography. Arteries with ≥50% diameter reduction were considered stenosed at renal arteriography. Receiver operating characteristic curve analysis was performed to determine the optimal parameters. The sensitivity, specificity, positive and negative predictive values, and accuracy at various threshold values were calculated. Results Sixteen accessory renal arteries (15 normal, one mild stenosis) were identified at arteriography. Of the 153 main renal arteries demonstrated at arteriography, 79 were normal or demonstrated stenosis Conclusion It should be feasible and necessary to measure three representative hemodynamic parameters (RAR, RPSV, and RIR or RSR) in the diagnosis of ≥50% RAS. The PSVs in the abdominal aorta and renal artery can be affected by factors other than RAS, which may decrease the accuracy of RAR. However, post-PSV ratios are minimally affected by PSV in the abdominal aorta or by an equal proportional change in PSVs in the renal artery trunk and its intrarenal renal arteries; therefore, use of post-PSV ratios dramatically overcomes some limitations of RAR.