title: Renal artery stenosis: endovascular flow wire study for validation of Doppler US.
abstract: 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.
authors.affiliation: Department of Diagnostic Radiology, Leiden University Hospital, The Netherlands.
authors.forename: V P
authors.initials: VP
authors.lastname: van der Hulst
authors.forename: J
authors.initials: J
authors.lastname: van Baalen
authors.forename: L S
authors.initials: LS
authors.lastname: Kool
authors.forename: J H
authors.initials: JH
authors.lastname: van Bockel
authors.forename: A R
authors.initials: AR
authors.lastname: van Erkel
authors.forename: J
authors.initials: J
authors.lastname: Ilgun
authors.forename: P M
authors.initials: PM
authors.lastname: Pattynama
mesh_terms: 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