Hepatic parenchymal transection increases liver volume but not function after portal vein embolization in rabbits.

BACKGROUND Associating liver partition with portal vein ligation for staged hepatectomy induces more extensive liver hypertrophy than ligation alone; however, the mechanisms underlying the accelerated liver regrowth and the functional quality of the hypertrophic liver are presently elusive. This study, therefore, investigated the effect of parenchymal transection on liver volume and function after portal vein embolization in a standardized rabbit model. METHODS Twelve rabbits were subjected to portal vein embolization of the cranial liver lobes and randomized between parenchymal transection of the left lateral liver lobe versus no transection (portal vein embolization only). Liver volume of the nonembolized liver lobe was assessed using computed tomography-volumetry, and liver uptake function was determined by 99mTc-mebrofenin hepatobiliary scintigraphy before and 3 and 7 days after portal vein embolization. RESULTS The increase in nonembolized liver volume 3 days after portal vein embolization was 2.7-fold greater in the transected group compared with the portal vein embolization only group (56 ± 16% vs 21 ± 12%, respectively, P < .01) and 1.7-fold greater 7 days after portal vein embolization (113 ± 34% vs 68 ± 24%, P < .01). Liver uptake function did not differ between groups before portal vein embolization (8.4 ± 3.7%/min in the transection group vs 8.9 ± 1.6%/min) on day 3 (33.2 ± 4.7% after transection vs 30.3 ± 4.6%/min, respectively) and day 7 after portal vein embolization (42.6 ± 8.4% vs 39.1 ± 5.3%/min, respectively). CONCLUSION Parenchymal transection after portal vein embolization increases liver growth in terms of volume but not function. These results indicate that the rapid volume increase observed after associating liver partition with portal vein ligation for staged hepatectomy does not coincide with the clinically more relevant functional increase. Quantitative liver function tests might be essential in associating liver partition with portal vein ligation for staged hepatectomy to better assess the hypertrophy response and improve clinical decision-making.