Comparison of Clinical Outcomes Using Left and Right Liver Grafts in Adult-to-adult Living-donor Liver Transplantation: A Retrospective Cohort Study Using the Korean Organ Transplantation Registry

Background. Living-donor liver transplantation has been widely performed as an alternative to the scarce liver grafts from deceased donors. More studies are reporting favorable outcomes of left liver graft (LLG). This study compared the clinical outcomes between living-donor liver transplantation using LLG and right liver graft (RLG) with similar graft-to-recipient body weight ratios. Methods. This study analyzed 4601 patients from a multicenter observational cohort using the Korean Organ Transplantation Registry between 2014 and 2021. After matching the Model for End-stage Liver Disease score and graft-to-recipient body weight ratios because of the extremely different number in each group, the LLG and RLG groups comprised 142 (25.1%) and 423 (74.9%) patients, respectively. Results. For donors, the median age was higher in the LLG group than in the RLG group (34 y [range, 16-62 y] versus 30 y [16-66 y]; P = 0.002). For recipients, the LLG group showed higher 90-d mortality than the RLG group (11 [7.7%] versus 9 [2.1%]; P = 0.004). The long-term graft survival was significantly worse in the LLG group (P = 0.011). In multivariate Cox proportional hazards regression analysis for graft survival, LLG was not a significant risk factor (hazard ratio, 1.01 [0.54-1.87]; P = 0.980). Otherwise, donor age (≥40 y; 2.18 y [1.35-3.52 y]; P = 0.001) and recipients' body mass index (<18.5 kg/m²; 2.98 kg/m² [1.52-5.84 kg/m²]; P = 0.002) were independent risk factors for graft survival. Conclusions. Although the short-term and long-term graft survival was worse in the LLG group, LLG was not an independent risk factor for graft survival in multivariate analysis. LLGs are still worth considering for selected donors and recipients regarding risk factors for graft survival.