Inclusion Criteria:  Adult primary liver transplant recipients of DBD or DCD donor Livers perfused on OCS Liver System  Donor Exclusion Criteria:  Donor livers with accessory arterial blood supply requiring back table anastomosis, major traumatic injury, or hematoma; or Split donor liver; or DCD donor liver with >30 minutes of warm ischemic time (defined as from withdrawal of life support until donor liver cold flush); or DCD donors age >55 years; or DCD donor liver with macrosteatosis of >15% Living donors Donors with positive serology for HIV, Hep B and C Donors with macrosteatosis of ≥40%  Recipient Exclusion Criteria:  Fulminant liver failure; or Concurrent (multi-organ transplant) or previous solid organ or bone marrow transplant; or Chronic renal dialysis at time of transplant; or Dependency on more than 1 inotropic agent to maintain hemodynamics; or Ventilator dependent at time of transplant.