The short- and long-term outcomes in living-donor liver transplantation using small-for-size graft: A systematic review and meta-analysis

Background: A standard graft-to-recipient weight ratio (GRWR) >= 0.8% is widely accepted in living-donor liver transplantation (LDLT); however, the potential donor pool is expanded to patients adopting small-for-size graft (SFSGs) with GRWR <0.8%. This study aimed to investigate the effect of SFSG on short-and long-term outcomes following LDLT. Methods: Electronic databases were searched from January 1995 to January 2022 for studies comparing short-or long-term outcomes between patients with SFSG (GRWR <0.8%, SFSG group) and sufficient volume graft (GRWR >= 0.8%, non-SFSG group). The primary outcomes were one-, three-, and five-year overall survival (OS) and graft survival (GS), while the secondary outcome was postoperative complications. Results: Twenty-four studies comprising 7996 patients were included. In terms of OS, SFSG group had poor three-year OS (HR: 1.48, 95% CI [1.01, 2.15], p = 0.04), but there were no significant differences between two groups in one-year OS (HR: 1.50, 95% CI [0.98, 2.29], p = 0.06) and five-year OS (HR: 1.40, 95% CI [0.95, 2.08], p = 0.02). In GS, there were no significant differences in one-year (HR 1.31, 95% CI [1.00, 1.72], p = 0.05), three-year (HR 1.33, 95% CI [0.97, 1.82], p = 0.07), and five-year GS (HR 1.17, 95% CI [0.95, 1.44], p = 0.13). The SFSG group had comparable postoperative complications, except for a high incidence of vascular complications and small-for-size syndromes. Conclusions: Expanding the potential donor pool in LDLT to SFSG with GRWR <0.8% can be acceptable in terms of comparable long-term OS and GS, despite the risk for vascular complications and small-for-size syndrome.