A reproducible model of acute hepatic failure by transient ischemia in the pig

Abstract

A model of transient acute hepatic failure has been developed in the pig. Three days after a functional end-to-side portacaval shunt was introduced, 15 ambulant animals underwent total liver ischemia for 4 to 6 h by the closure of a mechanical clamp surrounding the hepatic artery. Four of the eight animals subjected to 4 hr of ischemia survived. All but one of the animals undergoing 6 hr of hepatic ischemia developed grade 4 encephalopathy after 24 to 30 hr and died within 50 hr. Quantitative estimation of liver cell necrosis revealed less than 40% necrosis in the survivors, and approximately 62% (range 49-75%) in animals who died of hepatic coma. As far as the putative toxins are concerned, significant differences were found between animals undergoing 4 and those undergoing 6 hr of ischemia, especially in the plasma ammonia levels and the plasma ratios for tyrosine and phenylalanine. Plasma arginine levels had fallen to zero in both groups at 24 hr and only rose to preischemic values in animals who survived. This large animal model fulfills the accepted criteria of potential reversibility, reproducibility, and death due to hepatic failure.