Younger Age is an Independent Factor for Graft Weight Overestimation: Analysis of the Clinical Impact on Recipient Outcomes in 340 Japanese Living Liver Donors.

BACKGROUND: Accurate preoperative estimation of graft weight is essential for improving outcomes in living donor liver transplantation. METHODS: This retrospective study sought to identify factors associated with graft weight overestimation. From April 2006 to August 2015, 340 living donors were assigned to no-overestimate (n = 284) or overestimate (n = 56) groups. We defined graft weight overestimation as a discrepancy ≥15% between estimated graft volume and actual graft weight. Donor data were compared, and associated factors for graft weight overestimation were analyzed. Recipient outcomes were compared between the groups according to identified factors. RESULTS: Donors were significantly younger in the overestimate group than in the no-overestimate group (35.0 vs. 46.0 years; p < 0.001). Multivariate analysis identified donor age <45 years as an independent risk factor for graft weight overestimation (odds ratio 2.068; 95% confidence interval 1.114-3.839; p = 0.021). Among recipients with donors <45 years (n = 168), incidence of small-for-size dysfunction (SFSD) was significantly higher in the overestimate group than in the no-overestimate group (7/37 patients vs. 7/131 patients; p = 0.016); no significant difference was observed among recipients with donors ≥45 years (n = 172). First-year mortality was lower in SFSD recipients with donors <45 years (14.3 vs. 60.9%, p = 0.007). Among recipients with younger donors, graft survival was not significantly different between overestimate and no-overestimate groups. CONCLUSIONS: Younger donor age was an independent risk factor for graft weight overestimation leading to SFSD in recipients, but did not impair graft survival.