Noninvasive evaluation of renal artery stenosis and renovascular resistance: Experimental and clinical studies

Abstract Doppler ultrasound was used to detect experimental and clinical renal artery stenosis (RAS) and increased renovascular resistance (RVR). Parameters assessing RAS included elevated systolic frequency and spectral broadening, while diastolic/systolic frequency ratios predicted elevated RVR. In canine models these parameters detected graded RAS before reduction in renal blood flow. Index values were 88% sensitive and 100% specific in identifying RAS with gradients ≥25 mm Hg. Diastolic/systolic frequency correlated well with increased RVR induced by microsphere injections (p