(1527) Exceptions for Status 1B Listing for Pediatric Liver Transplantation: Is It an Equitable Process?

Introduction: Children with acute on chronic liver failure (ACLF) may be listed as Status 1B on the United Network for Organ Sharing (UNOS) waitlist, which places them at high priority for liver transplantation. They achieve Status 1B priority by fulfilling pre-determined criteria explicitly or via the exception process, where transplant programs petition due to clinical urgency. We hypothesized that there were differences in demographics, diagnoses, incidence of organ failures, and pre- and post-transplant outcomes between the explicit and exception Status 1B groups.

Methods: Using the UNOS database, we identified 367 children with ACLF who were listed for liver transplantation as Status 1B between Jan 2007 and Mar 2019. Children with metabolic diseases and malignancies were excluded. Data was analyzed using SAS software, with chi square analyses to compare metrics between groups.

Results: Of 367 children with ACLF listed as Status 1B, 110 (30%) were listed by exception. There were no significant differences between explicit and exception groups in age, sex, or race/ethnicity (p=0.19, p=0.61, p=0.85). The most common underlying diagnosis category for each group was cholestatic liver disease (82% and 73%), with the most common diagnosis being biliary atresia. Incidence of cumulative organ failures and MELD/PELD scores were significantly lower in the exception group at multiple time points (% not shown, p< 0.001). There were also regional differences in how frequently the exception process was utilized (% not shown, p=0.03). Overall, the transplant rate was 68%, recovery without transplant was 0%, and pre-transplant mortality was 30% with no significant difference between groups (p=0.32, p=1.0, p=0.10). Post-transplant mortality within 1 year was 8%, with no significant difference between groups (p=0.88)

Conclusions: Our study showed significant utilization (30%) of the exception process in listing children with ACLF as Status 1B. While children listed by exception had significantly lower incidence of cumulative organ failure at multiple time points, they had similar rates of pre- and post-transplant mortality to the explicit group. Further study is needed to understand why these children are at higher risk than expected and how transplant programs identify the need to petition for Status 1B by exception.