Diagnosis of renal artery stenosis in transplanted kidneys: Value of Doppler waveform analysis of the intrarenal arteries

Abstract

OBJECTIVE. The objective of this study was to determine in renal transplant patients if the acceleration time and subjective assessment of dampening of the waveforms from the intrarenal arteries improves the accuracy of detecting a hemodynamically significant (≥50%) proximal arterial stenosis compared with measurements of peak systolic velocity from s main renal artery. MATERIALS AND METHODS. In 15 patients, the findings of 19 Doppler sonograms and corresponding arteriograms of their renal transplants were reviewed, with arteriography serving as the gold standard. Four patients had a significant proximal arterial stenosis; three were of the main renal artery and one was of the adjacent external lilac artery proximal to the anastomosis with the renal artery. RESULTS. We found a significant prolongation of the acceleration time in patients with a significant proximal arterial stenosis (p = .0004). Use of a threshold acceleration time of 0.10 sec or subjective assessment of dampening of the waveforms resulted in an accuracy of 95% in detecting a significant proximal arterial stenosis. This compared with an accuracy of 62% in detecting a significant proximal arterial stenosis using a peak systolic velocity threshold of 2.0 m/sec as the sole criterion. Using intrarenal arterial Doppler waveform parameters alone would have spared arteriography in 11 patients and would have detected three of four significant proximal arterial stenoses. CONCLUSION. In this study, Doppler waveform analysis of the intrarenal arteries improved the accuracy of screening for a significant proximal arterial stenosis. The results suggest that such analyses can be used to spare many patients with suspected renal vascular hypertension from unnecessary arteriography.