Viability testing of discarded livers with normothermic machine perfusion: Alleviating the organ shortage outweighs the cost

BACKGROUND

Over 700 donor livers are discarded annually in the United States due to high risk of poor graft function. The objective of this study was to determine the impact of using normothermic machine perfusion to identify transplantable livers among those currently discarded.

STUDY DESIGN

A series of 21 discarded human livers underwent viability assessment during normothermic machine perfusion. Cross-sectional analysis of the Scientific Registry of Transplant Recipients database and cost analysis was performed to extrapolate the case series to national experience.

RESULTS

21 discarded human livers were included in the perfusion cohort. 11 of 20 (55%) eligible grafts met viability criteria for transplantation. Grafts in the perfusion cohort had a similar donor risk index compared with discarded grafts (n = 1402) outside of New England in 2017 and 2018 (median [IQR]: 2.0 [1.5, 2.4] vs. 2.0 [1.7, 2.3], P = .40). 705 (IQR 677-741) livers were discarded annually in the United States since 2005, translating to the potential for 398 additional transplants nationally. The median cost to identify a transplantable graft with machine perfusion was $28,099 USD.

CONCLUSIONS

Normothermic machine perfusion of discarded livers could identify a significant number of transplantable grafts, significantly improving access to liver transplantation.

Pumping new life into old ideas: Preservation and rehabilitation of the liver using ex situ machine perfusion

Recent advances in machine perfusion technology have reinvigorated the field of liver transplantation with the possibilities of vastly improving the efficiency and safety of the life-saving procedure. With this improved preservation technology, transplant surgeons are now able to use previously untransplantable donor livers without significantly compromising patient outcomes. Early clinical studies demonstrate the ability to extend preservation times and assess a graft's potential viability using normothermic machine perfusion, in addition to restoring the energy supply in donor livers by supporting metabolism through circulation of vital nutrients and blood-based oxygen carriers. Future endeavors for surgeons and scientists should focus on improving criteria to assess viability, optimizing protocols for perfusion research, investigating mechanisms of poor graft viability, and targeting these mechanisms with novel therapies to improve graft function prior to transplantation. Long-term goals include extending preservation times on the scale of days to weeks, enabling long-distance organ sharing, and establishing regional organ perfusion centers to streamline the procurement, perfusion, and transplantation process.