SUPERIORITY OF ACCELERATION AND ACCELERATION TIME OVER PULSATILITY AND RESISTANCE INDEXES AS SCREENING-TESTS FOR RENAL-ARTERY STENOSIS

Objective To compare the accuracy of four echo-Doppler-derived velocim etric indices (pulsatility and resistance indices, acceleration and ac celeration time) in detecting renal artery stenosis in hypertensive pa tients. Patients and methods In 73 hospitalized patients with moderate -to-severe hypertension, 18 of whom had normal renal arteries and 55 r enal artery stenosis (50-95%) either atherosclerotic (30 cases, five b ilateral) or fibromuscular dysplasia (25 cases, two bilateral), we mea sured the four velocimetric indices using the lateral abdominal approa ch and sampling Doppler waveforms distally to the stenosis, The diagno stic accuracy of each index was calculated using as cut-off limit the ideal threshold determined with the receiver-operating characteristic curves. Results On average all of the indices were altered significant ly in arteries with stenosis of both aetiologies with respect to norma l arteries, the alterations of pulsatility and resistance indices bein g, however, less pronounced than those of acceleration and acceleratio n time, particularly in atherosclerotic stenosis, With the cut-off lim its of 0.93, 0.59 and 7.4 m/s(2) and 60 ms, respectively, for pulsatil ity and resistance indices, acceleration and acceleration time, their diagnostic accuracies were 80, 73, 93 and 92%. In stenotic arteries, o nly the acceleration time was correlated with the degree of arterial n arrowing, whereas, in normal arteries, only pulsatility and resistance indices were directly correlated with the age of patients. Conclusion s Acceleration and acceleration time are more accurate indices than pu lsatility and resistance to screen for renal artery stenosis, probably because their alterations are less attenuated by the counterbalancing effects of age and of atherosclerosis.