title: Renal Vasoconstriction Occurs Early During Shockwave Lithotripsy in Humans.
abstract: BACKGROUND
  In animal models, pretreatment with low-energy shock waves and a pause decreased renal injury from shockwave lithotripsy (SWL). This is associated with an increase in perioperative renal resistive index (RI). A perioperative rise is not seen without the protective protocol, which suggests that renal vasoconstriction during SWL plays a role in protecting the kidney from injury. The purpose of our study was to investigate whether there is an increase in renal RI during SWL in humans.
  
  
  METHODS
  Subjects were prospectively recruited from two hospitals. All subjects received an initial 250 shocks at low setting, followed by a 2-minute pause. Treatment power was then increased. Measurements of the renal RI were taken before start of procedure, at 250, after 750, after 1500 shocks, and at the end of the procedure. A linear mixed-effects model was used to compare RIs at the different time points.
  
  
  RESULTS
  Fifteen patients were enrolled. Average treatment time was 46 ± 8 minutes. Average RI at pretreatment, after 250, after 750, after 1500 shocks, and post-treatment was 0.67 ± 0.06, 0.69 ± 0.08, 0.71 ± 0.07, 0.73 ± 0.07, and 0.74 ± 0.06, respectively. In adjusted analyses, RI was significantly increased after 750 shocks compared with pretreatment (p = 0.05).
  
  
  CONCLUSIONS
  Renal RI increases early during SWL in humans with the protective protocol. Monitoring for a rise in RI during SWL is feasible and may provide real-time feedback as to when the kidney is protected.
authors.affiliation: 1 Department of Urology, University of Washington School of Medicine , Seattle, Washington.
authors.forename: Franklin C
authors.initials: FC
authors.lastname: Lee
authors.affiliation: 1 Department of Urology, University of Washington School of Medicine , Seattle, Washington.
authors.forename: Ryan S
authors.initials: RS
authors.lastname: Hsi
authors.affiliation: 1 Department of Urology, University of Washington School of Medicine , Seattle, Washington.|2 Division of Urology, Department of Veteran Affairs Medical Center , Seattle, Washington.
authors.forename: Mathew D
authors.initials: MD
authors.lastname: Sorensen
authors.affiliation: 3 Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington , Seattle, Washington.
authors.forename: Marla
authors.initials: M
authors.lastname: Paun
authors.affiliation: 3 Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington , Seattle, Washington.
authors.forename: Barbrina
authors.initials: B
authors.lastname: Dunmire
authors.affiliation: 4 Department of Biostatistics, Indiana University Schools of Medicine and Public Health , Indianapolis, Indiana.
authors.forename: Ziyue
authors.initials: Z
authors.lastname: Liu
authors.affiliation: 3 Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington , Seattle, Washington.
authors.forename: Michael
authors.initials: M
authors.lastname: Bailey
authors.affiliation: 1 Department of Urology, University of Washington School of Medicine , Seattle, Washington.
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Harper
mesh_terms: D058186:Acute Kidney Injury / Q000503:physiopathology / Q000517:prevention & control*; D000368:Aged; D001794:Blood Pressure / Q000502:physiology; D015331:Cohort Studies; D005260:Female; D006761:Hospitals; D006801:Humans; D007668:Kidney / Q000098:blood supply*; D007669:Kidney Calculi / Q000628:therapy*; D008096:Lithotripsy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012077:Renal Artery / Q000502:physiology*; D014655:Vascular Resistance / Q000502:physiology*; D014661:Vasoconstriction / Q000502:physiology*