Initial Efforts to Stratify Patients and Donors Utilizing Normothermic Machine Preservation of Livers for Transplant

Since FDA approval in 2021, normothermic machine perfusion (NMP) has emerged as a transformative tool to expand transplantation access for patients with end-stage liver disease. This study details the design, implementation, and outcomes of our liver NMP program, highlighting implementation of a stratification algorithm for grafts into low-, medium-, and high-risk categories and evaluation of high-risk grafts from the first 100 cases. A secondary analysis compares NMP outcomes with historical cohorts. The final analysis included 53 grafts from donation after brain death (DBD) and 39 from donation after circulatory death (DCD) donors, excluding eight NMP grafts that were not transplanted. No significant differences were observed in allograft dysfunction, primary non-function, biliary or arterial complications, or patient survival, even among high-risk graft recipients. NMP significantly reduced intraoperative cryoprecipitate (0.41 vs. 1.44 units, p = 0.003) and platelet (0.59 vs. 1.56 units, p = 0.001) use in DCD recipients. While recipients of DBD-NMP grafts experienced longer ICU stays (17.17 vs. 8.96 days, p = 0.03) and higher rates of renal replacement therapy (41.14% vs. 20.75%, p = 0.04) than the historic cohort, inpatient length of stay and long-term dialysis requirements were unaffected. Higherrisk graft use facilitated transplant access for patients with lower MELD scores at our center. These findings highlight NMP's potential to safely expand the donor pool, facilitating transplantation of previously non-utilized livers while maintaining comparable outcomes. The risk stratification developed alongside our program provides a practical algorithm to advance equity in organ allocation through NMP by enabling safe access to high-risk grafts and demonstrates its value in optimizing liver transplantation practices.