Survival benefit of liver transplantation utilizing marginal donor organ according to ABO blood type

The current liver transplantation (LT) allocation policy focuses on the MELD scores, often overlooking factors like blood type and survival benefits. Understanding blood types' impact on survival benefits is crucial for optimizing the MELD 3.0 classification. This study used the United Network for Organ Sharing national registry database (2003-2020) to identify LT characteristics per ABO blood type and to determine the optimal MELD 3.0 scores for each blood type, based on survival benefits. The study included candidates of LT aged 18 years or older listed for LT (total N=150,815; A: 56,546, AB: 5841, B: 18,500, O: 69,928). Among these, 87,409 individuals (58.0%) underwent LT (A:32,156, AB: 4,362, B: 11,786, O: 39,105). Higher transplantation rates were observed in AB and B groups, with lower median MELD 3.0 scores at transplantation (AB: 21, B: 24 vs. A/O: 26, p <0.01) and shorter waiting times (AB: 101 d, B:172 d vs. A: 211 d, O: 201 d, p <0.01). A preference for donation after cardiac death (DCD) was seen in A and O recipients. Survival benefit analysis indicated that B blood type required higher MELD 3.0 scores for transplantation than A and O (donation after brain death transplantation: ≥15 in B vs. ≥11 in A/O; DCD transplantation: ≥21 in B vs. ≥11 in A, ≥15 in O). The study suggests revising the allocation policy to consider blood type for improved post-LT survival. This calls for personalized LT policies, recommending higher MELD 3.0 thresholds, particularly for individuals with type B blood.