title: Detection of significant renal artery stenosis with color Doppler sonography: combining extrarenal and intrarenal approaches to minimize technical failure.
abstract: BACKGROUND
  Renal artery disease can cause both hypertension and renal failure, and color Doppler sonography (CDS) may be a good screening method to detect it. Presently reported techniques of Doppler sonography have either a high rate of technical failure (4-42%), or low sensitivity and specificity, or detect only stenoses greater than 70%, or exclude patients with renal failure from analysis. In previous studies Doppler detection of renal artery stenosis (RAS) was based either on increased intrastenotic velocity or on the detection of post-stenotic Doppler phenomena. In the present prospective study these two approaches were combined to detect RAS (> or = 50% diameter reduction) in 226 consecutive patients (144 with normal and 82 with impaired renal function).
  
  
  METHODS
  Stenosis of 50% or more was diagnosed if the maximal systolic velocity in the main renal artery was more than 180 cm/sec and velocity in the distal renal artery less than one quarter of the maximum velocity. When these velocities could not be determined a diagnosis of RAS was made when the acceleration time in intrarenal segmental arteries exceeded 70 msec. All patients subsequently underwent arteriography as the gold standard for the detection of RAS.
  
  
  RESULTS
  With this combined approach, the technical failure rate of CDS was 0% in both patients with normal and those with impaired renal function. The mean time required for the Doppler investigation was 17 minutes. The sensitivity and specificity for detection of a significant stenosis in a given vessel (including accessory arteries), as compared to angiography, were 96.7% and 98.0%.
  
  
  CONCLUSIONS
  Color Doppler sonography, evaluating both main renal and intrarenal arteries is an ideal screening method for detection of RAS of 50% or more because it allows accurate and rapid detection of stenosis in all patients, irrespective of renal function.
authors: Department of Nephrology, Medizinische Hochschule, Hannover, Germany.
authors: J
authors: J
authors: Radermacher
authors: A
authors: A
authors: Chavan
authors: J
authors: J
authors: Schäffer
authors: B
authors: B
authors: Stoess
authors: A
authors: A
authors: Vitzthum
authors: V
authors: V
authors: Kliem
authors: J
authors: J
authors: Rademaker
authors: J
authors: J
authors: Bleck
authors: M J
authors: MJ
authors: Gebel
authors: M
authors: M
authors: Galanski
authors: R
authors: R
authors: Brunkhorst
mesh_terms: D001783:Blood Flow Velocity; D005260:Female; D006801:Humans; D006978:Hypertension, Renovascular / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D011859:Radiography; D012077:Renal Artery / Q000000981:diagnostic imaging; D012078:Renal Artery Obstruction / Q000000981:diagnostic imaging*; D012680:Sensitivity and Specificity; D013997:Time Factors; D018615:Ultrasonography, Doppler, Color / Q000379:methods