Age Matters: What Affects the Cumulative Lifespan of a Transplanted Liver?

Abstract

Objective: To assess factors affecting the cumulative lifespan of a transplanted liver.

Background: Liver aging is different from other solid organs. It is unknown how old a liver can actually get after liver transplantation.

Methods: Deceased donor liver transplants from 1988 to 2021 were queried from the United States UNOS registry. Cumulative liver age was calculated as donor age + recipient graft survival.

Results: In total, 184,515 livers were included. Most were donation after brain death donors (n = 175,343). The percentage of livers achieving >70, 80, 90, and 100 years cumulative age was 7.8% (n = 14,392), 1.9% (n = 3576), 0.3% (n = 528), and 0.01% (n = 21), respectively. The youngest donor age contributing to a cumulative liver age >90 years was 59 years, with posttransplant survival of 34 years. In pediatric recipients, 736 (4.4%) and 282 livers (1.7%) survived >50 and 60 years overall, respectively. Transplanted livers achieved cumulative age >90 years in 2.86 per 1000 and >100 years in 0.1 per 1000. The U.S. population at large has a cumulative "liver age" >90 years in 5.35 per 1000 persons, and >100 years in 0.2 per 1000. Livers aged >60 years at transplant experienced both improved cumulative survival ( P < 0.0001) and interestingly improved survival after transplantation ( P < 0.0001). Recipient warm ischemia time of >30 minutes was most predictive of reduced cumulative liver survival overall (n = 184,515, hazard ratio = 1.126, P < 0.001) and excluding patients with mortality in the first 6 months (n = 151,884, hazard ratio = 0.973, P < 0.001).

Conclusions: In summary, transplanted livers frequently get as old as those in the average population despite ischemic-reperfusion-injury and immunosuppression. The presented results justify using older donor livers regardless of donation type, even in sicker recipients with limited options.