Impact of the acuity circle model for liver allocation on multivisceral transplant candidates

Abstract

Liver allocation was updated on February 4, 2020, replacing a Donor Service Area (DSA) with acuity circles (AC). The impact on waitlist outcomes for patients listed for combined liver-intestine transplantation (multivisceral transplantation [MVT]) remains unknown. The Organ Procurement and Transplantation Network/United Network for Organ Sharing database was used to identify all candidates listed for both liver and intestine between January 1, 2018 and March 5, 2021. Two eras were defined: pre-AC (2018-2020) and post-AC (2020-2021). Outcomes included 90-day waitlist mortality and transplant probability. A total of 127 adult and 104 pediatric MVT listings were identified. In adults, the 90-day waitlist mortality was not statistically significantly different, but transplant probability was lower post-AC. After risk-adjustment, post-AC was associated with a higher albeit not statistically significantly different mortality hazard (sub-distribution hazard ratio[sHR]: 8.45, 95% CI: 0.96-74.05; p=.054), but a significantly lower transplant probability (sHR: 0.33, 95% CI: 0.15-0.75; p=.008). For pediatric patients, waitlist mortality and transplant probability were similar between eras. The proportion of patients who underwent transplant with exception points was lower post-AC both in adult (44% to 9%; p=.04) and pediatric recipients (65% to 15%; p=.002). A lower transplant probability observed in adults listed for MVT may ultimately result in increased waitlist mortality. Efforts should be taken to ensure equitable organ allocation in this vulnerable patient population.