title: Doppler ultrasound velocities and resistive indexes immediately after pediatric liver transplantation: normal ranges and predictors of failure.
abstract: OBJECTIVE
  We sought to determine the ranges of Doppler ultrasound findings immediately after pediatric liver transplantation that are associated with successful outcomes or postoperative complications.
  
  
  METHODS
  This study included consecutive children who underwent Doppler ultrasound less than 48 hours after liver transplantation from 2001 to 2011. Operative reports and clinical outcome data were recorded. We had 110 patients (54% girls) with mean age at transplantation of 2.9 years (median, 1.3 years; range, 0-14 years) and a median follow-up interval of 3.5 years. Two pediatric radiologists reviewed ultrasound images in consensus. We computed descriptive statistics, interindex correlations, and analysis of variance.
  
  
  RESULTS
  Twenty-four of 110 patients had a vascular complication, most commonly hepatic arterial thrombosis (seven patients). Compared with published adult normal values, normal pediatric Doppler parameters at postoperative day 1 trended toward higher normal velocities and resistive indexes (up to 0.95). Absent or low-velocity common hepatic artery flow less than 50 cm/s or a common hepatic artery resistive index less than 0.50 were significantly associated with hepatic artery thrombosis, whereas absent or low-velocity portal venous flow less than 30 cm/s or low-velocity hepatic venous flow less than 25 cm/s were significantly associated with vascular complications and a monotonic hepatic venous waveform was significantly associated with venous complications.
  
  
  CONCLUSIONS
  Flow in a pediatric liver on the first day after transplantation is normally hyperdynamic, especially in the youngest transplant recipients, and, as a result, low velocities or resistive indexes are particularly concerning for complications. The pediatric-specific ranges of expected posttransplantation Doppler ultrasound findings presented in this article should assist in identifying normal variation and potentially life-threatening complications.
authors.affiliation: 1 Department of Radiology and Diagnostic Imaging, University of Alberta, 2A2.41 WMC, 8440 - 112 St, Edmonton, AB T6G 2B7 Canada.
authors.forename: Lucy H
authors.initials: LH
authors.lastname: Jamieson
authors.forename: Bo
authors.initials: B
authors.lastname: Arys
authors.forename: Gavin
authors.initials: G
authors.lastname: Low
authors.forename: Ravi
authors.initials: R
authors.lastname: Bhargava
authors.forename: Surekha
authors.initials: S
authors.lastname: Kumbla
authors.forename: Jacob L
authors.initials: JL
authors.lastname: Jaremko
mesh_terms: D000293:Adolescent; D001783:Blood Flow Velocity; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008099:Liver / Q000098:blood supply* / Q000000981:diagnostic imaging*; D016031:Liver Transplantation; D008297:Male; D011183:Postoperative Complications / Q000000981:diagnostic imaging*; D012016:Reference Values; D012189:Retrospective Studies; D018608:Ultrasonography, Doppler; D014655:Vascular Resistance
keywords: Doppler ultrasound; liver transplantation; pediatric; resistive disease