Hemodynamic and biochemical changes during normothermic and hypothermic sanguinous perfusion of the porcine hepatic graft

Using an ex vivo liver sanguinous perfusion system, hemodynamic and biochemical changes of the porcine livers were studied, which were preserved cold (4 degrees C) for 24 hr in University of Wisconsin solution and reperfused with normothermic (37 degrees C) (n = 8) or hypothermic (32 degrees C) (n = 8) blood for 3 hr. Six more livers were reperfused with normothermic blood (37 degrees C) immediately after procurement as controls. The total hepatic blood flow was adjusted to 1 ml/min/g liver weight, in which hepatic artery and portal vein flows were administered at a 1:2 ratio. In livers stored cold for 24 hr in UW solution and perfused normothermically, a statistically higher hepatic artery resistance was exhibited at 30 and 60 min after reperfusion (P less than 0.05), and there was lower bile output (P less than 0.05) at 90 and 120 min as compared to the controls. In livers stored cold for 24 hr in UW solution and perfused hypothermically, as compared to ones perfused normothermically, statistically higher hepatic-artery and portal-vein resistances (P less than 0.05) were observed throughout the perfusion period and 60 min after reperfusion, respectively. In addition, bile output and oxygen consumption of these livers were statistically lower than those of ones perfused normothermically (P less than 0.05). In contrast, chemistries of the perfusate of livers perfused hypothermically were comparable to ones perfused normothermically. Histologic examination of the liver perfused hypothermically demonstrated hepatic arterial and/or portal venous congestion and mild-to-moderate hemorrhage in the portal triads. This study suggests that livers preserved for a prolonged period of time demonstrate a high hepatic arterial resistance shortly after revascularization, and that recipient hypothermia after revascularization may be a risk factor for the development of hepatic arterial thrombosis following liver transplantation.