Haemodynamic changes in ischaemic vs. anhepatic pig experimental model of acute liver failure

New model of veno-venous bypass for management of anhepatic phase in experimental study on dogs

Blood is shunted from the inferior vena cava and portal vein to the superior vena caval system to prevent congestion in the lower parts of the body during the anhepatic phase (AP) of liver transplantation. It leads to overload in the superior vena caval system retarding cranial outflow due to a nonphysiological blood redistribution. To overcome this problem, we developed a new bypass in dogs: blood is shunted from the inferior (caudal) vena cava and portal vein to the suprahepatic inferior (caudal) vena cava. This model was compared with traditional one with or without a pump. Blood pressure and flow parameters were estimated during 3 hours of AP in four groups of four dogs each. The current study showed that a nontraditional scheme of venous bypass reduced circulatory complications during AP, especially in the cranial vena caval system, although a low rate of congestion remains in the caudal vena cava and portal vein systems. Whereas the same scheme using a pump effectively prevented congestion in all of the systems: cranial, caudal, and portal. We concluded that application of a nontraditional bypass scheme, providing venous blood return into suprahepatic part of caudal vena cava, can be considered to be a method of choice for experimental liver transplantation.

Large animal models of fulminant hepatic failure in artificial and bioartificial liver support research

Among the large range of organs involved in the field of tissue engineering (skin, blood vessels, cartilage, etc.) the liver has been given broad attention in the last decade. Liver support systems encompassing artificial and bioartificial systems are applied to treat patients with fulminant hepatic failure (FHF) as a bridge to orthotopic liver transplantation or to liver regeneration. To test safety, technical applicability and therapeutic effect of liver support systems, reliable animal models are needed. Due to the complexity of FHF many diverse attempts have been made to develop an adequate animal model to study liver failure, liver regeneration and liver support systems. In this paper an overview is given of the different models and their advantages and disadvantages are discussed. Suggestions are made for the most suitable large animal model to test liver support systems.

Acute hepatic failure in swine: hepatectomy versus vascular occlusion

The two most promising surgical animal models of fulminant hepatic failure (FHF) for investigation of the safety and efficacy of new treatment modalities were analyzed in a porcine study. Animals underwent total hepatectomy or devascularization of hepatic artery and portal vein followed by portocaval (PC) shunting. Survival time, technical feasibility, safety, and reproducibility of the models were investigated. Devascularization seems to be most useful for studying the development and treatment of FHF caused by ischemia and its side effects. Total hepatectomy is superior for investigation of the anhepatic status and treatment of FHF by bioartifical liver support systems.