Liver function maximum capacity test during normothermic regional perfusion predicts graft function after transplantation

Purpose In an effort to reduce waitlist mortality, extended criteria donor organs, including those from donation after circulatory death (DCD), are being used with increasing frequency. These donors carry an increased risk for postoperative complications, and balancing donor-recipient risks is currently based on generalized nomograms. Abdominal normothermic regional perfusion (aNRP) enables individual evaluation of DCD organs, but a gold standard to determine suitability for transplantation is lacking. This study aimed to incorporate individualized and predictive measurements of the liver maximum capacity (LiMAx) test to objectively grade liver function during aNRP and prevent post-op complications. Methods aNRP was performed to salvage 18 DCD liver grafts, otherwise discarded. Continuous variables were presented as the median with the interquartile range. Results The liver function maximum capacity (LiMAx) test was successfully performed within the aNRP circuit in 17 aNRPs (94%). Donor livers with good lactate clearance during aNRP demonstrated significantly higher LiMAx scores (396 (301-451) mu g/kg/h versus those who did not 105 (70-158) mu g/kg/h; P = 0.006). This was also true for manifesting stress hyperglycemia > 20 mmol/l (P = 0.032). LiMAx score correlated with alanine aminotransferase (ALT; R = - 0.755) and aspartate transaminase (AST; R = - 0.800) levels during perfusion and distinguished livers that were selected for transplantation (397 (346-453) mu g/kg/h) from those who were discarded (155 (87-206) mu g/kg/h; P < 0.001). Twelve livers were accepted for transplantation, blinded for LiMAx results, and all had LiMAx scores of > 241 mu g/kg/h. Postoperatively, LiMAx during aNRP displayed correlation with 24-h lactate levels. Conclusions This study shows for the first time the feasibility to assess liver function during aNRP in individual donor livers. LiMAx presents an objective tool to predict donor liver function and risk of complications in the recipient, thus enabling individualized matching of donor livers for an individual recipient. The LiMAx test may present a valuable test for the prediction of donor liver function, preventing post-transplant complication, and personalizing the selection of donor livers for individual recipients.