Sequential Normothermic Regional Perfusion and Normothermic Machine Perfusion May Improve Hepatic Artery Resistance and Accelerate Lactate Normalization in DCD Livers

Introduction: Normothermic regional perfusion (NRP) has shown promise in increasing DCD utilization. However, typical functional parameters like lactate are confounded in NRP by the ischemic insult to the whole body. Normothermic machine perfusion (NMP) after NRP could provide a more accurate functional assessment. While two case reports (n=8 total) have utilized NRP+NMP there has not been a comparison of functional parameters and flow parameters for DCD going to NMP directly vs sequential NRP+NMP. Methods: Three discarded human DCD livers were obtained. Organs were discarded for the following reasons-Organ1 had undergone NRP for a duration of 3hrs and was discarded on account of cholestasis with a direct bilirubin of 4.1 preop; Organ2- was hypotensive for >24hrs with systolic 60mmhg or less and had to be taken emergently for DCD recovery; Organ3 had gangrenous bowel with free perforation. All three grafts were around 1kg (1140+/-130gms). Flow, pressure and resistance were recorded. Lactate was serially measured. Biopsy of the liver was taken on NMP. Results: Of the three livers one NMP only liver did not normalize lactate. NRP+NMP livers showed lower artery opening pressures and earlier lactate normalization than NMP only liver. Organ warm times, lactate levels, flows, pressures are noted in Table. Conclusions: These data show that DCD livers undergoing NRP+NMP have lower initial intrahepatic resistance and therefore hepatic artery pressures and demonstrate a more rapid normalization of lactate than DCD livers just undergoing NMP. Therefore, we conclude that for DCD livers flow and lactate normalization can be enhanced by sequential NRP+NMP.