Risks of Living Donor Liver Transplantation Using Small-For-Size Grafts

Background: In living donor liver transplantation (LDLT), a graft-to-recipient weight ratio (GRWR) of under 0.8 is recognized as the critical graft size. Our aim was to compare the survival rates of recipients with small-for-size grafts (SFSG: GRWR <0.8), normal-sized grafts (NSG), and large-for-size grafts (LFSG: GRWR ≥ 3.5) and to investigate the mortality risk with SFSG. Methods: Between 1991 and April 2019, we performed 188 LDLT surgeries. Recently, we added splenectomy when portal vein pressure is high (>17 mm Hg) to interrupt the splenic bloodstream. We divided all LDLT cases retrospectively into 3 groups: an SFSG group (n = 22), NSG group (n = 154), and LFSG group (n = 12). We investigated the survival rates in these groups. Furthermore, we divided the SFSG group into 2 subgroups: an SFSG with splenectomy (SFSG+S) group (n = 7) and an SFSG without splenectomy group. We investigated the occurrence rates of lethal complications such as portal vein thrombosis, hepatic artery thrombosis, and hepatic vein thrombosis. Results: The 5-year survival rate in the SFSG group was significantly lower (52.8%) than in the other groups (NSG: 84.5%; LFSG: 83.3%), but that of the SFSG+S group was similar (80.0%) to that of other groups. There was no difference in the occurrence of postoperative complications such as portal vein thrombosis, hepatic artery thrombosis, or hepatic vein thrombosis between the SFSG+S group and other groups. Conclusions: Graft survival of LDLT using SFSG+S was as good as that of normal-sized grafts. Reducing portal vein pressure was important for SFSG.