Renal artery stenosis: endovascular flow wire study for validation of Doppler US.
OBJECTIVE
To compare the accuracy of proximal and peripheral Doppler parameters for detection of renal artery stenosis (RAS).


METHODS
The authors obtained absolute velocities and peripheral Doppler waveforms in 16 stenotic and 14 normal renal arteries by using a 0.45-mm endovascular flow wire. Hemodynamically significant stenosis was established by measuring transstenotic invasive pressure gradients, with a 10 mm Hg or greater pressure drop indicating RAS. Accuracy of the Doppler parameters and of digital subtraction angiographic (DSA) results were compared by using receiver operating characteristic analysis.


RESULTS
Measurements of absolute velocities at the site of the stenosis (maximal peak systolic velocity [PSVmax], PSV ratio, renal artery-to-aortic PVS ratio) showed high accuracy for diagnosis of RAS similar to that of DSA (areas under the ROC curve were 0.96, 0.97, 0.93, respectively). The distal intrarenal Doppler indexes (notably loss of early systolic peak, acceleration, acceleration time, pulsatility index, and resistive index) did not show statistically significant correlation with RAS.


CONCLUSIONS
Doppler measurements in the main renal artery correlate well with RAS. The intrarenal Doppler spectrum, however, has no diagnostic value. The authors conclude that duplex Doppler US is not a suitable screening test for RAS.
van der Hulst
V P
VP
Department of Diagnostic Radiology, Leiden University Hospital, The Netherlands.
van Baalen
J
J
Kool
L S
LS
van Bockel
J H
JH
van Erkel
A R
AR
Ilgun
J
J
Pattynama
P M
PM
D015901:Angiography, Digital Subtraction; D001783:Blood Flow Velocity; D006801:Humans; D007668:Kidney / Q000098:blood supply; D011446:Prospective Studies; D012372:ROC Curve; D012077:Renal Artery / Q000000981:diagnostic imaging / Q000503:physiopathology; D012078:Renal Artery Obstruction / Q000000981:diagnostic imaging*; D012680:Sensitivity and Specificity; D018608:Ultrasonography, Doppler; D018084:Ultrasonography, Interventional