Segmental liver grafts with a calculated ideal liver weight (CILW) less than 40% may be associated with portal flow-related injuries and primary dysfunction. This study evaluated the effect of mesocaval shunts on the survival of grafts with a CILW less than 20%. Sixteen pigs underwent orthotopic transplantation of segmental liver grafts with a CILW less than 20%. In eight animals (study group), transplantation was combined with a mesocaval shunt, and eight animals served as controls without a mesocaval shunt. Liver function, systemic hemodynamics, portal vein pressure, intracranial pressure, and cerebral perfusion pressure were assessed postoperatively. The controls showed a rapid impairment of liver function reflected by a significant elevation in aspartate aminotransferase, international normalized ratio, bilirubin, and intracranial pressure and a decrease in cerebral perfusion pressure compared with the study group (P<0.05). Mesocaval shunts showed protective effects on grafts with CILW less than 20% and may have a clinical role in the salvage of small-for-size liver grafts.