Simultaneous hepatic and portal vein ligation induces rapid liver hypertrophy: A study in pigs

Background: Liver hypertrophy induced by partial portal vein occlusion (PVL) is accelerated by adding simultaneous parenchymal transection (“ALPPS procedure”). This preclinical experimental study in pigs tests the hypothesis that simultaneous ligation of portal and hepatic veins of the liver also accelerates regeneration by abrogation of porto-portal collaterals without need for operative transection. Methods: A pig model of portal vein occlusion was compared with the novel model of simultaneous portal and hepatic vein occlusion, where major hepatic veins draining the portal vein–deprived lobe were identified with intraoperative ultrasonography and ligated using pledgeted transparenchymal sutures. Kinetic growth was compared, and the portal vein system was then studied after 7 days using epoxy casts of the portal circulation. Portal vein flow and portal pressure were measured, and Ki-67 staining was used to evaluate the proliferative response. Results: Pigs were randomly assigned to portal vein occlusion (n = 8) or simultaneous portal and hepatic vein occlusion (n = 6). Simultaneous portal and hepatic vein occlusion was well tolerated and led to mild cytolysis, with no necrosis in the outflow vein–deprived liver sectors. The portal vein–supplied sector increased by 90 ± 22% (mean ± standard deviation) after simultaneous portal and hepatic vein occlusion compared with 29 ± 18% after PVL (P <.001). Collaterals to the deportalized liver developed after 7 days in both procedures but were markedly reduced in simultaneous portal and hepatic vein occlusion. Ki-67 staining at 7 days was comparable. Conclusion: This study in pigs found that simultaneous portal and hepatic vein occlusion led to rapid hypertrophy without necrosis of the deportalized liver. The findings suggest that the use of simultaneous portal and hepatic vein occlusion accelerates liver hypertrophy for extended liver resections and should be evaluated further.