ABO nonidentical liver transplantation disadvantages pediatric waitlist candidates with blood group O

Objectives: Timely availability of a suitable allograft helps offset pediatric liver transplant (pLT) waitlist mortality. Candidate-donor blood type matching (CDBM) is an important attribute for allograft allocation. Current policy allows for blood type (ABO) compatible non-identical transplants for pLT candidates with high acuity. Additionally, centers may use ABO incompatible allografts for pLT candidates when required. Methods: We conducted a retrospective analysis of the United Network for Organ Sharing (UNOS) database. We analyzed pediatric (<18 years) candidates listed for deceased donor liver-only transplant (DDLT) during the time-period 1/2008 to 12/2022. Specifically, we analyzed the impact of CDBM, including ABO non-identical LT on outcomes. Results: 72.4% of the 8976 pLT candidates included in our analyses underwent DDLT. 19.9% of pLTs were ABO nonidentical, and 4.9% were ABO incompatible. Nonidentical pLT recipients had significantly higher listing urgency and lower waitlist times. Nonidentical pLTs led to a net loss of allografts for blood type O and net gain of allografts for all other blood types. Candidates with blood type O had significantly higher waitlist time (62.5 vs. 48 days) and lower proportion of candidates undergoing DDLT (70.2% vs. 74.7%), when compared to blood type A. Conclusion: ABO nonidentical allografts result in timely transplant for pLT candidates with high acuity. Blood type O candidates are disadvantaged, while blood type A candidates are advantaged by ABO nonidentical allografts. The observations of our study, which differ from those of prior adult studies, could inform future policy changes pertaining to organ allocation based on CDBM.