SEGMENTAL STENOSIS OF THE RENAL-ARTERY - PATTERN-RECOGNITION OF TARDUS AND PARVUS ABNORMALITIES WITH DUPLEX SONOGRAPHY

Segmental renal artery branches were evaluated using color Doppler ima ging and pulsed Doppler spectral analysis in a prospective fashion in 56 patients with suspected peripheral vascular disease who underwent s ubsequent angiography. Thirty-four of the 56 patients were hypertensiv e. Pulsed Doppler waveform analysis was performed to assess accelerati on time, acceleration index, and loss of the normal early systolic pea k (ESP). These three parameters were compared with the findings obtain ed on subsequent angiograms to assess their efficacy for detecting gre ater than or equal to 60% renal arterial stenosis (RAS). Thirty-two ki dneys in 26 patients demonstrated angiographic evidence of greater tha n or equal to 60% stenosis. Three patients had multiple renal arteries , none of which were stenotic. No segmental arteries demonstrated sten osis. Evaluation of ESP proved to be the best of the three parameters evaluated for identifying greater than or equal to 60% stenosis. Loss of the ESP identified RAS with 95% sensitivity, 97% specificity, a 92% positive predictive value, a 98% negative predictive value, and 96% o verall accuracy. Two categories of waveform abnormalities, one moderat e and one more severe, were associated with a loss of ESP. Detection o f tardus and parvus abnormalities in the segmental renal arteries is a dvocated as an indirect means of diagnosing renal artery stenosis. Pat tern recognition of loss of the normal ESP had better sensitivity and specificity than acceleration time or acceleration index for diagnosin g greater than or equal to 60% RAS. The authors were unable to disting uish between renal artery occlusion with collateral arterial supply to the kidneys and severe main renal artery stenosis. However, they were successful in all kidneys in whom a patent renal artery was found at angiography.