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

Building on models developed for recipients of deceased donor liver transplant, a modified early allograft dysfunction score of bilirubin>10 or INR>1.6 at postoperative day 7 has been applied to patients undergoing living donor liver transplant. However, this score has never been validated in the living donor liver transplant population or separately analyzed in patients receiving left lobe (LL) grafts. A multicenter cohort of patients (Adult-to-Adult Living Donor Liver Transplantation Cohort Study [A2ALL]) and a single-center cohort University of California, San Francisco (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 recipients of right lobe (RL) and LL were created and bootstrap-validated, and their risk associations compared to modified early allograft dysfunction. In total, 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. Recipients of RL who scored above the RL score cut-point and recipients of LL who scored above the LL score cut-point had a 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 modified early allograft dysfunction score was only significantly associated with GL in recipients of RL (HR: 4.04, 95% CI: 2.40-6.80, p <0.001) but not in recipients of LL (HR: 1.98, 95% CI: 0.63-6.23, p =0.24). We developed and validated separate risk scores for recipients of RL and LL, which may allow for earlier and more accurate identification of patients at high risk of GL and early intervention to protect the graft.