Use of Ex Situ Machine Perfusion for Liver Transplantation: The National Experience

Machine perfusion (MP) for liver transplantation has become more widespread in the United States, but national studies on this growing practice are lacking. We investigated national use and outcomes of MP for liver transplantation.

Adult (≥18 y) liver recipients transplanted between January 1, 2016 and September 30, 2023 in the United Network for Organ Sharing database were included. We used Cox regression to compare 1-y posttransplant recipient survival and all-cause graft failure by use of MP and performed subgroup analyses among circulatory death (DCD) and brain death (DBD) donors.

Of 52 626 deceased donors with liver recovery, 1799 (3.5%) utilized MP. The proportion of all liver transplants using MP increased from 0.3% in 2016 to 15.5% in 2023. MP for DCD transplants increased from 0.8% in 2016 to 50.0% in 2023. Donors of MP grafts were older (47 [34-57] versus 42 [29-55] y, P < 0.001), had higher body mass indexes (28.3 [24.4-33.3] versus 27.3 [23.7-31.8] kg/m 2 , P < 0.001), and were more likely to be DCD (47.1% versus 9.3%, P < 0.001). Among DBD transplants, MP and non-MP DBD transplants had similar all-cause graft failure out to 1 y (adjusted hazards ratios, 1.12 [95% confidence interval, 0.87-1.43], P = 0.38). Among DCD transplants, MP recipients had improved survival out to 1 y (adjusted hazards ratios, 0.50 [95% confidence interval, 0.35-0.70], P < 0.001).

MP use in liver transplantation is rapidly expanding and is associated with favorable outcomes compared with cold storage. MP is associated with increased posttransplant survival for DCD transplants, highlighting the potential for MP to expand utilization of DCD grafts.