Normothermic machine perfusion for older transplant recipients

Elderly patients (≥65 years old) are increasingly undergoing liver transplantation and are more likely to be removed from the waitlist. Normothermic machine perfusion (NMP) holds promise in expanding the number of livers available for transplant and improving outcomes for marginal donors and recipients. We aimed to determine the impact of NMP on outcomes in elderly recipients at our institution and nationally using the UNOS database.

The use of NMP on outcomes in elderly recipients was reviewed using both the UNOS/SRTR database (2016-2022) and institutional data (2018-2020). Characteristics and clinical outcomes were compared between the NMP and static cold (control) groups within both populations.

Nationally, using the UNOS/SRTR database, we identified 165 elderly recipients from 28 centers who received a liver allograft undergoing NMP and 4270 that underwent traditional cold static storage. NMP donors were older (48.3 vs. 43.4 years, p < 0.01), had similar rates of steatosis (8.5% vs 8.5%, p = 0.58), were more likely to be from a DCD (41.8% vs 12.3%, p < 0.01), and had a higher donor risk index (DRI; 1.70 vs. 1.60, p < 0.02). NMP recipients had similar age but had a lower MELD score at transplant (17.9 vs. 20.7, p = 0.01). Despite increased marginality of the donor graft, NMP recipients had similar allograft survival and decreased length of stay, even after accounting for recipient characteristics including MELD. Institutional data showed that 10 elderly recipients underwent NMP and 68 underwent cold static storage. At our institution, NMP recipients had a similar length of stay, rates of complications, and readmissions.

NMP may mitigate donor risk factors that are relative contraindications for transplantation in elderly liver recipients, increasing the donor pool. The application of NMP in older recipients should be considered.