Perfusate Flavin Mononucleotide and D-Dimer as Viability Biomarkers in Australasia's First Hypothermic Machine...

Hypothermic oxygenated machine perfusion (HOPE) is a simple ex-situ treatment for liver grafts. However, it lacks viability assessment capabilities. Flavin mononucleotide (FMN) and D-dimer may be useful biomarkers of graft quality during HOPE. This exploratory study aimed to determine whether effluent FMN and D-dimer concentrations were associated with outcomes in liver transplants treated with HOPE. This is a retrospective, single-center study of all grafts treated with HOPE in New Zealand from 2022-2025. Fifty-four grafts were treated with HOPE. Effluent concentrations of FMN (n = 30) and D-dimer (n = 24) were analyzed. Post-transplant cholangiopathy (PTxC) with graft loss occurred in five recipients of donation after circulatory death grafts. The median summation of FMN concentrations taken over the first two hours of perfusion was higher in the PTxC group (four PTxC events among the 30 grafts with FMN measurements; p = 0.034). Decision curve analysis suggested that summated FMN models may add net benefit over default strategies, particularly in DCD grafts, although with only five outcome events these analyses do not define implantation thresholds. D-dimer concentrations were not significantly different in PTxC grafts (p > 0.05). Whilst perfusate FMN has promise as a predictor of PTxC in HOPE grafts, especially if summated over several time points, prospective external validation is required before it could contribute to transplantation decision-making.