Two‐stage portal flow modulation for volume‐augmented grafts in living donor liver transplantation: Rat model validation

Graft procurement in adult living donor liver transplantation (LDLT) faces persistent challenges in balancing volumetric adequacy and donor safety. This study introduces two-stage portal vein ligation and reperfusion for graft procurement in LDLT (PVLR-LT), which aims to expand the left lateral lobe for achieving adequate grafts, thereby circumventing technical and anatomical limitations of conventional approaches. In a rat model, the PVLR-LT group underwent selective portal vein ligation (step I) to induce targeted hypertrophy, followed by reperfusion and transplantation (step II). Outcomes were compared among PVLR-LT, negative controls, and standard-volume controls. Staged portal flow modulation effectively redistributed hepatic mass allocation, yielding grafts with graft recipient weight ratio approximately double that of negative controls and equivalent to standard-volume controls. Donors experienced no mortality, with only transient enzyme elevation. Recipient survival in the PVLR-LT group significantly exceeded that of the negative control group and was non-inferior to that of the standard-volume control group, while hepatic enzyme peaks were markedly lower than those in standard-volume control recipients. This study provides a promising proof of concept, establishing the feasibility of using PVLR-LT to convert the surgically straightforward left lateral segment into right lobe-sized grafts through staged portal flow modulation and demonstrating the translational potential for laparoscopic LDLT.