Minimum graft size calculated from preoperative recipient status in living donor liver transplantation

Small-for-size graft syndrome is an inevitable complication in living donor liver transplantation (LDLT). We hypothesized that graft weight (GW) measured after graft procurement is one of the variables predicting postoperative graft function. A total of 138 consecutive recipients of adult-to-adult LDLT between March 1999 and October 2014 were included in this study. We investigated the factors associated with small-for-size-associated graft loss (SAGL) to determine the GW required for each patient. Both preoperatively assessed and postoperatively obtained risk factors for SAGL were analyzed in univariate and multivariate logistic regression analysis. Twelve (8.8%) of the transplant recipients had SAGL. In multivariate logistic regression analyses using preoperatively assessed variables, the preoperative Model for End-Stage Liver Disease (MELD) score (P < 0.001) and actual GW/recipient standard liver volume (SLV) ratio (P = 0.008) were independent predictors of SAGL. The recommended graft volume by preoperative computed tomography volumetry was calculated as SLV × (1.616 × MELD + 0.344)/100/0.85 (mL) [MELD ≥ 18.2], or SLV × 0.35 (mL) [MELD < 18.2]. The required allograft volume in LDLT can be determined by the preoperative MELD score of the recipient, and patients with higher MELD scores require larger grafts or deceased donor whole liver transplant to avoid SAGL.