Difference between renal and splenic resistive index as a novel criterion in Doppler evaluation of renal artery stenosis

Detection of renal artery stenosis (RAS) using Doppler is difficult to evaluate, particularly under conditions such as bilateral RAS or difficultly accessible renal arteries (RA). The objective of the present study was to assess the utility of splenic arterial compared to renal flow as an additional parameter in the Doppler evaluation of RAS. The difference between the resistive indices (RI) determined in renal and splenic parenchymal arteries (RIK-S) was evaluated in 181 hypertensive subjects without any evidence of RAS. Subsequently 47 RA in 24 patients with suspected RAS were angiographically assessed. A RIK-S of 0.055 (median) was determined in the population without any evidence of RAS similar to RA with angiographically excluded stenosis (RIK-S 0.068). In contrast, in angiographic proven RAS, RIK-S was significantly lower (-0.050; P<.005). The assessment of the RIK-S, proved to be an easily feasible parameter, which improves the diagnostic accuracy in the detection of RAS.