The Optimal Timing of Portal and Hepatic Vein Ligation for Increasing Liver Remnant Volume in Rats

Portal vein embolization combined with hepatic vein embolization enhances future liver remnant hypertrophy in major hepatectomy. However, the optimal timing, simultaneous or sequential, remains undefined. This study evaluates the optimal timing of hepatic vein ligation (HVL) in combination with portal vein ligation (PVL) using a rat model.

PVL was performed for the middle and left lateral lobes, while HVL was applied to the hepatic vein of the left lateral lobe. Rats were allocated to the PVL only, PVL + HVL, or sham group. HVL was added at -3, 0, +3, +24, or +72 h relative to PVL, yielding seven groups. Nonligated liver volume was assessed at 7 d after PVL. Four representative groups were sacrificed at 1 d after PVL for histological evaluation and assessment of liver hypertrophy-related mediators.

PVL + HVL (0 h) induced the most marked hypertrophy of nonligated lobes. In the sequential groups, early addition of HVL (+3 h) produced greater hypertrophy than later additions. Histologically, the PVL + HVL groups showed more severe injury, with the simultaneous group demonstrating the largest necrotic area. Hepatocyte growth factor expression in the ligated lobe was significantly higher in the PVL + HVL groups than the PVL only group, and serum hepatocyte growth factor at 7 d was significantly higher in the simultaneous group. Ki67 expression was highest in the simultaneous group at 1 and 7 d.

Simultaneous HVL with PVL was the most effective strategy for promoting hypertrophy of nonligated lobes and enhancing regeneration-associated mediator expression.