Novel Real-time Prediction of Liver Graft Function During Hypothermic Oxygenated Machine Perfusion Before Liver Transplantation

Abstract

The aim of this study was to determine the predictive value of machine perfusate analysis on graft outcome. BACKGROUND: Ex situ machine perfusion (MP) is gaining increasing interest to potentially repair injured organs and to assess organ function. In the field of liver transplantation, however, no studies exist on reliable prediction of graft function during MP. METHODS: We have used hypothermic oxygenated perfusion (HOPE) for donation after circulatory death (DCD) or extended criteria donation after brain death (DBD) human liver grafts during the last 7 years. Our series includes 100 HOPE-treated liver-transplanted patients with an overall tumor-censored 5-year graft survival of 89%. We monitored 54 livers during HOPE in terms of fluorometric analysis of released mitochondrial flavin (flavin mononucleotide, FMN) in the machine perfusate. RESULTS: Real-time optical measurement of mitochondrial FMN release in machine perfusates of livers disclosed a strong correlation with lactate clearance and coagulation factors at day 1 and 2 after transplantation. Receiver-operating characteristic curve analysis revealed an area under the curve (AUROC) of 0.79 [95% confidence interval (CI), 0.62-0.97] for severe allograft dysfunction and for early graft loss (AUROC 0.93, 95% CI, 0.84-1.0). CON-CLUSIONS: Assessment of flavin, a marker of mitochondrial complex I injury, in the perfusate provides a fast prediction of liver graft function and loss during ex situ MP before implantation. This finding may have high clinical relevance, as liver grafts from extended DBD or DCD donors carry considerable risks for recipients. On-line estimation of outcome before implantation would therefore substantially increase safe utilization of liver grafts.

Ischemia-Reperfusion Injury in Marginal Liver Grafts and the Role of Hypothermic Machine Perfusion: Molecular Mechanisms and Clinical Implications

“…The Zurich group has recently presented a new mitochondrial marker to assess the viability of entire liver grafts during HOPE. Real-time fluorometric analysis of mitochondrial flavin mononucleotide (FMN) in the HOPE perfusate predicted human liver function, complications, and graft loss prior to transplantation [78]. The use of this surrogate parameter could facilitate proper clinical decision making on whether to accept or decline high-risk ECD allografts.…”

“…This marker is currently validated in other solid organs and also in the RCT of the Guarrera group [63]. Importantly, the quantification of FMN is possible in real time, requiring only a spectroscope, and reliably predicts graft survival at a threshold of 10,000 A.U., detected within the first 30-45 min of HOPE [78].…”

“…In the near future FMN as well as other mitochondrial and inflammatory biomarkers will be assessed not only in other organs, but also during different perfusion approaches at various temperatures [78].…”

Machine Perfusion: Cold versus Warm, versus Neither. Update on Clinical Trials

“…However, a recent study by Muller et al shows that real-time fluorometric analysis of perfusate flavin, a marker of mitochondrial injury, can be predictive of graft function and loss during cold MP. 22 This achievement has high clinical relevance, and real-time estimation of liver function during cold preservation could substantially increase safe utilization of liver grafts.…”

Biomarkers of Liver Injury during Transplantation in an Era of Machine Perfusion

“…The latter was determined experimentally by using liver tissue homogenates processed after the cessation of perfusion, and thus, the assessment of ATP was not contemporaneous and at present cannot be used as a biomarker of graft function. The Dutkowski group have demonstrated that real-time analysis of mitochondrial flavin in the perfusate during HMP, correlated with post-transplant allograft dysfunction and early graft loss (AUC 0.79 and 0.93, respectively) and also mirrored changes in lactate clearance and coagulation factors production [51]. Results such as these await clinical validation, but these show it might be possible to assess liver viability in real-time, during hypothermic MP without a dependence on the conventional functional parameters.…”