title: Hepatic arterial buffer response fails to restore hepatic oxygenation after temporary liver dearterialization in canines.
abstract: BACKGROUND
  Hepatic artery thrombosis is a rare but extremely troublesome condition after liver transplantation. Recently, urgent arterial revascularization has been used as rescue therapy, leading to improved graft and patient survivals. Hepatic artery ligation produces a progressive reduction in portal vein blood flow. Theoretically, a hyperemic response may be expected following hepatic artery reperfusion (hepatic artery buffer response, HABR). In this study, we tested the hypothesis that HABR can maintain adequate liver oxygenation after temporary liver dearterialization.
  
  
  METHODS
  Seven dogs (19.7 +/- 1.2 kg) subjected to 60 minutes of hepatic artery occlusion were observed for 120 minutes thereafter. Systemic hemodynamics was evaluated through Swan-Ganz and arterial catheters, and splanchnic perfusion by portal vein and hepatic artery blood flows (PVBF and HABF) via an ultrasonic flowprobe. Liver enzymes (ALT and LDH) and systemic and hepatic oxygen delivery (DO2hepat) were calculated using standard formulae.
  
  
  RESULTS
  Hepatic artery occlusion induced a progressive reduction in PVBF and DO2hepat. A complete restoration of HABF after hepatic artery declamping was observed; however, the DO2hepat (33.3 +/- 5.9 to 16.5 +/- 5.9 mL/min) did not return to the baseline levels.
  
  
  CONCLUSIONS
  Temporary hepatic artery occlusion induced a progressive decrease in portal vein blood flow during ischemia, an effect that continued during the reperfusion period. The hepatic artery blood flow was promptly restored after declamping. However, HABR was not able to restore hepatic oxygen delivery to baseline levels during the reperfusion period.
authors.affiliation: Division of Applied Physiology, Heart Institute-InCor, University of São Paulo Medical School, Sao Paulo, Brazil. expcruzjr@incor.usp.br
authors.forename: R J
authors.initials: RJ
authors.lastname: Cruz
authors.forename: E A
authors.initials: EA
authors.lastname: Ribeiro
authors.forename: L F
authors.initials: LF
authors.lastname: Poli de Figueiredo
authors.forename: O R
authors.initials: OR
authors.lastname: Cantos
authors.forename: M
authors.initials: M
authors.lastname: Rocha e Silva
mesh_terms: D000818:Animals; D001783:Blood Flow Velocity; D001794:Blood Pressure; D002339:Carotid Arteries / Q000502:physiology; D003251:Constriction, Pathologic / Q000503:physiopathology*; D004285:Dogs; D006439:Hemodynamics; D006499:Hepatic Artery / Q000502:physiology*; D006975:Hypertension, Portal / Q000503:physiopathology; D008099:Liver / Q000502:physiology*; D008102:Liver Circulation / Q000502:physiology*; D008297:Male; D023421:Models, Animal; D012039:Regional Blood Flow