Haemodynamic and metabolic consequences of reversed portal venous blood flow after side-to-side portacaval shunt in the dog.

The immediate haemodynamic and metabolic effects of reversed portal blood flow after side-to-side portacaval shunt were studied in 9 normal anaesthetized dogs, and compared to those observed after end-to-side shunt in the same animals. Blood flow in the hepatic artery (HA) and portal vein (PV) was measured using electromagnetic flowmeters. The magnitude of the HA hyperaemic response to side-to-side shunt was similar to that found after end-to-side shunt, but approximately one-third of the flow left the liver via the PV. There was no significant correlation between the HA response and the magnitude of reversed PV flow after side-to-side shunt. Despite fairly well preserved total hepatic oxygen consumption in both groups, there was a statistically significant decrease in the side-to-side series; moreover, only 13% of the total hepatic oxygen consumption was derived from blood draining the liver via the PV. It is concluded that the substantial quantity of portally drained blood after side-to-side shunt traverses metabolically inefficient pathways in the liver, and may have a detrimental influence on long-term liver function.