Validation of risk factors for graft-to-recipient weight ratio less than 0.8 graft in living donor liver transplantation with single center data

Background: The use of small grafts, defined by a graft-to-recipient weight ratio (GRWR) less than 0.8, is possibly associated with an increased risk of graft loss in living donor liver transplantation (LDLT).This study aims to validate risk factors for graft loss in LDLT with GRWR<0.8 using single-center data.Methods: LDLT recipients, who received GRWR<0.8graft at Severance Hospital, between July 2007 and December 2022, were categorized based on the number of risk factors identified in previous Korean multicentric study: recipient age ≥60 years, model for end-stage liver disease (MELD) score ≥15, and male donor.Baseline characteristics and graft survival were compared among these groups.Results: The median GRWR was 0.74 (interquartile range 0.69-0.78)and minimum was 0.49.Recipients with more risk factors exhibited lower graft survival rates: 100% at 5 years in the Risk 0 group (n=18), 72.7% in the Risk 1 group (n=20), and 54.5% in the Risk≥2 group (n=18, p=0.015).This trend was similar in subgroups of right lobe graft and the others (left lobe plus right posterior lobe), although not statistically significant.Donor age did not significantly affect graft survival in GRWR<0.8transplants (78.9% for donor age≥45 vs. 69.2%for donor age<45, p=0.25). Conclusion:This study confirms that the number of risk factors, including recipient age, MELD score, and donor sex, significantly impacts graft survival in LDLT with GRWR<0.8.These findings highlight the need for careful recipient and donor selection to improve outcomes in LDLT.