Survival of the Liver After Gradual Devascularization

Abstract

In one group of male and female dogs,gradual complete occlusion of the portal vein was effected by placing 2 constricting ties on the portal vein. The surviving dogs were re-operated upon after a period of time and the hepatic artery and its collaterals were excised completely. In another group the hepatic artery and its collaterals were excised and in some the portal vein was exposed and a thread was passed around it and left loose. The surviving animals were re-operated upon later, at which time the portal vein was obstructed. Almost complete devascularization of the liver by excision of the hepatic artery and occlusion of the portal vein, performed in 2 stages, was better tolerated when the hepatic artery was excised in the 1st stage and the portal vein was obstructed later than when the procedure was done in reversed order. Excision of the hepatic artery and its collaterals was followed by extensive adaptive mechanisms which frequently enabled the liver to survive after subsequent occlusion of the portal vein. Elimination of the portal circulation was compensated by the hepatic artery and did not necessitate extensive adaptation of the liver. Therefore, subsequent excision of the arterial circulation will affect a liver not adjusted to lower O2 supplies and that has no portal circulation for additional supplies of O2 to tide it over until a proper adaptation is developed. Excision of the hepatic artery, combined with a loose thread around the portal vein, led to increased mortality also demonstrating the importance of unimpeded portal circulation for survival of the liver following excision of the hepatic artery.