Validation and refinement of early allograft dysfunction criteria in living donor liver transplantation

Introduction: Building on models developed on deceased donor liver transplant recipients, a modified early allograft dysfunction (mEAD) score of bilirubin>10 or INR>1.6 at post operative day (POD) 7, has been applied to patients undergoing living donor liver transplant (LDLT). However, this score has never been validated in the LDLT population or separately analyzed in patients receiving left lobe grafts. Methods: A multi-center cohort of patients (A2ALL) and a single-center cohort (UCSF) were combined. Kaplan-Meier estimates were computed for graft loss (GL) and Cox-proportional hazards models were used to evaluate lab values from 1-week post-transplant. Separate multivariable risk scores for GL in right lobe (RL) and left lobe (LL) recipients were created and bootstrap-validated, and their risk associations compared to mEAD. Results: 724 and 156 patients with RL and LL grafts, respectively, were included in this analysis. GL occurred in 7.5% of patients with RL and 7.8% patients with LL. RL recipients who scored above the RL score cut-point and LL recipients who scored above the LL score cut-point had significantly higher risk of GL (RL: HR 6.00, 95% CI 3.15-11.4, p <0.001; LL: HR 12.6, 95% CI 3.80-42.0, p <0.001). The mEAD score was only significantly associated with GL in RL recipients (HR 4.04, 95% CI 2.40-6.80, p <0.001) but not in LL recipients (HR 1.98, 95% CI 0.63-6.23, p =0.24). Conclusions: We developed and validated separate risk scores for RL and LL recipients, which may allow for earlier and more accurate identification of patients at high risk of graft loss and early intervention to protect the graft.