Introduction: Machine perfusion can expand transplantation opportunities of ECD (Extended  Criteria Donor) and DCD (Donation after Circulatory Death). HOPE(hypothermic oxygenated machine perfusion) and SNMP(subnormotermic machine perfusion) have incredible potential to recover these donor organs. Although FMN(flavin mononucleotide)^[1] is a promising candidate for predicting mitochondrial disorders to evaluate organ quality, organ viability assessment technologies have not been established. In this study, the integrated organ viability assessment method, which combines FMN, metabolic index, and homogenous perfusion index, is proposed and evaluated this method with the reperfusion model of the porcine experiment.
Method: Porcine livers were procured under several warm ischemic time conditions(45,60 min).  harvested livers were perfused with HOPE or SNMP. During machine perfusion, FMN, pressure, flow rate, vascular resistance, and metabolic indices such as oxygen consumption and pH were measured and analyzed with proposed indexes. The spatial perfusion characteristics were obtained from time-series fluorescence intensity distribution measurements using ICG to evaluate homogenous perfusion prior to transplantation. The organ viabilities were confirmed with the ischemia-reperfusion model with diluted autologous blood under body temperature.
Results: The results of the HOPE condition is described as represent result here. The FMN index and metabolic index calculated with oxygen consumption indicate a good correlation between the lactate variation during reperfusion. The time-series fluorescence intensity distribution measurements using ICG can calculate the spatial perfusion characteristics index, and this index indicates a correlation with lactate clearance. These integrated indexes can predict quantitatively homogeneous perfusion prior to reperfusion.
Conclusion: The integrated organ viability assessment method with FMN, metabolic index, and homogenous perfusion index has the potential to predict organ viability for hypothermic and subnormothermic machine perfusion.

^[1] Schlegel A, Muller X, Mueller M et al. Hypothermic oxygenated perfusion protects from mitochondrial injury before liver transplantation., EBioMedicine 2020; 60: 103014.