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

## TL;DR

This study introduces a two-stage portal vein technique in rat models to improve liver graft size and survival in living donor liver transplants.

## Contribution

A novel two-stage portal flow modulation method is proposed to enhance graft volume and recipient outcomes in liver transplantation.

## Key findings

- Staged portal flow modulation produced grafts with a graft recipient weight ratio double that of negative controls.
- Recipient survival in the PVLR-LT group was significantly higher than in the negative control group.
- The technique caused less hepatic injury compared to standard same-volume graft transplants.

## Abstract

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.

This study presents a two‐stage portal flow modulation strategy for graft procurement in living donor liver transplantation with the aim of expanding left lateral lobe grafts, thereby circumventing technical and anatomical limitations of conventional approaches. In a rat model, this approach achieved significantly higher recipient survival than that achieved with conventional same‐lobe‐graft transplants, and caused less hepatic injury than standard same‐volume‐graft transplants.