Is It Time to Introduce Ex-Situ Normothermic Machine Perfusion in Paediatric Liver Transplantation?

BACKGROUND

The clinical use of normothermic machine perfusion in liver transplantation currently excludes paediatric recipients due to the challenges of perfusing smaller grafts and risk of portal hyperperfusion injury. This study aimed to evaluate the haemodynamic conditions and histological changes of left lateral segment grafts (LLSG) during long-term normothermic machine perfusion (LT-NMP).

METHODS

Human livers underwent LT-NMP and were split within 24 h of reperfusion into a LLSG and extended right graft (ERG). The LLSG consisted of segments 2 and 3, the coeliac trunk, left portal vein and left hepatic duct, to simulate a realistically-sized graft for clinical use. Vascular haemodynamic parameters, biochemical markers including endothelin-1 and histopathological signs of portal hyperperfusion injury were measured.

RESULTS

Ten LLSGs were assessed. The median survival time was 5.7 days after splitting. LLSGs had higher portal venous resistance but similar weight-adjusted flow compared to ERGs. In the LLSGs, endothelin-1 levels remained low and there were no significant changes in histological signs of hyperperfusion injury over time.

CONCLUSIONS

This is the first preclinical model to demonstrate that LT-NMP of LLSGs does not cause significant hyperperfusion injury. This opens the opportunity to expand the use of NMP to resuscitate marginal grafts in paediatric liver transplantation.