Evolution Under Normothermic Machine Perfusion of Type 2 Donation After Cardiac Death Livers Discarded as Nontransplantable

Abstract Background Type 2 donation after cardiac death (DCD) represents an underused source of grafts for liver transplantation. In our center, normothermic regional perfusion and strict selection criteria have led to acceptable postoperative results after transplanting type 2 DCD livers. However, many of these grafts are still discarded before transplantation. We believe that the suitability of these organs may be improved by adding normothermic machine perfusion (NMP) to our current procedure. Materials and methods A total of 5 type 2 DCD livers discarded for transplantation were submitted to normothermic regional perfusion and 12 h of NMP. The macroscopic aspect of the liver, vascular and bile flows, and pH were continuously monitored. Serial perfusate analyses and liver biopsies were performed. After NMP, the microscopic appearance of the liver parenchyma and the bile ducts was analyzed. Results All the grafts showed hemodynamic stability during the NMP. The alanine aminotransferase peak during NMP correlated with the warm ischemia time (Pearson correlation of 0.933, p 0.021). After an initial period of acidosis, the grafts were generally able to spontaneously correct pH and lactate levels without the need for additional bicarbonate. Livers with favorable bile duct histology generally started bile production earlier and registered higher bile flows. Conclusions NMP represents a feasible procedure for use with type 2 DCD livers. The pH and lactate correction and the bile flows appear to be significant factors associated with graft viability. However, these favorable results should be confirmed in a clinical transplant setting.