Portal vein embolization induces more liver regeneration than portal vein ligation in a standardized rabbit model.

BACKGROUND

Portal vein ligation (PVL) and portal vein embolization (PVE) are used to induce hypertrophy of the future remnant liver before major liver resection. The aim of our study was to compare the hypertrophy response of the liver after PVL versus PVE in a rabbit model.

METHODS

Twenty rabbits were divided into an embolization group (n = 10) and a ligation group (n = 10). Both groups were divided in 2 subgroups of 5 rabbits that were humanely killed after days 7 and 14. The portal vein branches to the 3 cranial liver lobes (80% of the liver) were occluded. Regeneration of the caudal liver lobe was measured using volumetry based on computed tomography on days 3, 7, 10, and 14. Immunohistochemistry for Ki-67 and RAM11 was performed to quantify proliferating cells and macrophages. In addition, tissue tumor necrosis factor-α and interleukin-6 were assessed.

RESULTS

The caudal liver volume increased over time in both groups (P < .001), but this increase was greater after PVE than after PVL (P = .001) with a mean degree of hypertrophy of 15% ± 4% and 20% ± 2%, respectively. When comparing the groups on the separate time points, a difference was found on days 10 and 14 (P = .008 and P = .016, respectively). These data were confirmed by Ki-67 staining, which showed a greater number of proliferating hepatocytes on day 7 after embolization (P = .016). Cytokine analysis of liver tissue did not show significant differences between the ligation and embolization groups on days 7 and 14.

CONCLUSION

PVE is superior to PVL in terms of the extent of the hypertrophy response in this rabbit model.