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 (SFSGthornS) 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 SFSGthornS 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 SFSGthornS group and other groups. Conclusions. Graft survival of LDLT using SFSGthornS was as good as that of normal-sized grafts. Reducing portal vein pressure was important for SFSG.