title: Preliminary assessment of captopril sonography in screening for renal artery stenosis.
abstract: OBJECTIVE
  We assessed the usefulness of the resistive index (RI) and renal length in predicting a significant renal artery stenosis (RAS) and evaluated the effect of captopril on the RI in kidneys with and without a significant RAS.
  
  
  METHODS
  The RIs and renal lengths of both kidneys were measured in 39 patients who were referred for captopril renography for suspected renovascular hypertension. The difference in RIs (delta RI), the smaller RI (SRI), the difference in lengths (delta L), and the shorter length (SL) of the patient's two kidneys were determined. The accuracy of each of these parameters was calculated using captopril renography (n = 39) and arteriography (n = 9) as the gold standards.
  
  
  RESULTS
  There was a significant difference in the delta RI (P < .05), SRI (p < .001), and delta L (p < .05) in patients with a positive captopril renogram for a significant RAS. Captopril increased delta RI (p = .052) in patients with a positive captopril renogram (n = 6). Use of an SRI threshold of less than .55 resulted in ultrasound being as accurate as captopril renography in predicting an angiographically documented stenosis of greater than or equal to 50%.
  
  
  CONCLUSIONS
  The RI and renal length are useful in detecting a significant RAS. In this preliminary study, captopril was shown to increase delta RI in patients with a significant RAS, but larger prospective studies are necessary to further assess the value of captopril sonography in detecting a significant RAS.
authors.affiliation: Department of Radiology, University of Rochester Medical Center, NY 14642-8648, USA.
authors.forename: R H
authors.initials: RH
authors.lastname: Gottlieb
authors.forename: J L
authors.initials: JL
authors.lastname: Lieberman
authors.forename: V N
authors.initials: VN
authors.lastname: Ghaed
authors.forename: E B
authors.initials: EB
authors.lastname: Grossman
authors.forename: D L
authors.initials: DL
authors.lastname: Waldman
authors.forename: M V
authors.initials: MV
authors.lastname: Azodo
authors.forename: G H
authors.initials: GH
authors.lastname: Watt
authors.forename: W B
authors.initials: WB
authors.lastname: Robinette
authors.forename: N L
authors.initials: NL
authors.lastname: Carson
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology; D002216:Captopril / Q000494:pharmacology; D002648:Child; D005260:Female; D006801:Humans; D006978:Hypertension, Renovascular / Q000175:diagnosis; D007465:Iodohippuric Acid; D007668:Kidney / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011877:Radionuclide Imaging; D012078:Renal Artery Obstruction / Q000000981:diagnostic imaging* / Q000503:physiopathology; D016284:Technetium Tc 99m Pentetate; D014463:Ultrasonography; D014655:Vascular Resistance / Q000187:drug effects
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D007465:Iodohippuric Acid; D002216:Captopril; D016284:Technetium Tc 99m Pentetate