What is the correct aortic renal artery ratio for a stenosis in ultrasound?

3.5. Nobody judges by just one number. Having said that, most labs consider abnormal (60-99% stenosis of renal artery) renal to aortic systolic velocity ration of greater then 3.5 this is not, however, validated after stenting, the velocities tend to be higher.
3.5 or greater. A ratio of 3.5 or greater is indicative of significant renal artery stenosis.