title: The value of Doppler resistive index and peak systolic velocity in the evaluation of porcine renal obstruction.
abstract: OBJECTIVE
  We evaluated the use of Doppler resistive indexes and systolic velocities as diagnostic tools in a partially obstructed animal model.
  
  
  METHODS
  We studied 12 normal pigs by Doppler sonography, which served as control units. In 9 subjects partial ureteral obstruction was then created surgically, and 3 continued as controls. The presence or absence of obstruction was confirmed by ultrasound, antegrade nephrostography and intrapelvic pressure monitoring. Doppler parameters were measured 1 hour to 21 days postoperatively. Resistive index, and angle corrected peak and mean systolic velocities were measured bilaterally from samplings of interlobar and arcuate arteries. An average of 4 samplings per kidney was obtained at each session. Data from the control and obstruction groups were compared for statistical differences.
  
  
  RESULTS
  In controls mean resistive index was 0.53, and peak and mean systolic velocities were 0.38 and 0.26 m. per second, respectively. In the subacute period after obstruction (defined as days 4 to 21) mean resistive index was 0.54, and peak and mean systolic velocities were 0.33 and 0.22 m. per second, respectively. Compared to control data there was no significant change in resistive index after obstruction (p = 0.6). However, peak and mean systolic velocities showed significant downward trends (p < 0.05).
  
  
  CONCLUSIONS
  Known small sequential changes in renal blood flow after ureteral obstruction are reflected in flow velocities, as measured by duplex Doppler sonography. However, resistive indexes are not useful in assessing these changes in renal blood flow, and they do not correlate with the presence or absence of obstruction in this animal model.
authors.affiliation: Division of Pediatric Urology, Children's Hospital of Vanderbilt University Medical Center, Nashville, Tennessee, USA.
authors.forename: J C
authors.initials: JC
authors.lastname: Pope
authors.forename: M
authors.initials: M
authors.lastname: Hernanz-Schulman
authors.forename: P R
authors.initials: PR
authors.lastname: Showalter
authors.forename: T C
authors.initials: TC
authors.lastname: Cole
authors.forename: F F
authors.initials: FF
authors.lastname: Schrum
authors.forename: D
authors.initials: D
authors.lastname: Szurkus
authors.forename: J W
authors.initials: JW
authors.lastname: Brock
mesh_terms: D000818:Animals; D001783:Blood Flow Velocity; D005260:Female; D011859:Radiography; D013552:Swine; D013599:Systole; D018608:Ultrasonography, Doppler; D014517:Ureteral Obstruction / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D014655:Vascular Resistance