Clinical Significance of Grade A Small-for-size Syndrome after Living Donor Liver Transplantation Utilizing the New Definition of Diagnostic Criteria: An International Multicenter Study

Background. New diagnostic criteria have recently been established to classify small-for-size syndrome (SFSS) after living donor liver transplantation into 3 groups based on severity. This study aimed to evaluate the clinical impact of grade A SFSS and identify the mortality risk. Methods. We collected data from 406 patients diagnosed with grade A SFSS after living donor liver transplantation. Grade A SFSS is characterized by total bilirubin >5 mg/dL on postoperative day (POD) 7 or total bilirubin >5 mg/dL or ascites >1 L/d on POD 14. After propensity score matching, 193 patients were categorized into the up-trend group, down-trend group, and ascites group, with 43 patients (22.3%) in the up-trend group (total bilirubin on POD 7 < POD 14), 107 patients (55.4%) in the down-trend group (total bilirubin on POD 7 > POD 14), and 43 patients (22.3%) in the ascites group (only satisfying ascites criteria). Results. There was no significant difference in survival between patients with grade A SFSS and those without SFSS (P = 0.152). The up-trend group showed a higher 90-d mortality rate than the down-trend and ascites groups (P = 0.025). The 1-y survival rate differed significantly between the groups (87.6%, 91.9%, and 97.7%, respectively; P = 0.044). The independent risk factors for survival were up-trend of total bilirubin, recipient age (65 y and older), model for end-stage liver disease score (≥30), and ABO incompatibility. Patients with ≥2 risk factors had worse survival rates than those with none and only 1 risk factor (P < 0.001). Conclusions. Although the survival rate was comparable between the grade A SFSS and non-SFSS cohorts, the up-trend group showed worse survival. Aggressive interventions should be considered for up-trend patients with risk factors.