Regional Variation in Early Effects of Acuity Circle-Based Liver Allocation

T. Ivanics¹, S. Nagai², T. Kitajima², S. Shimada², T. Shamaa², K. Collins², M. Rizzari², A. Yoshida², D. Moonka², M. Abouljoud²

¹University of Toronto - University Health Network, Toronto, ON, Canada, ²Henry Ford Hospital, Detroit, MI

Meeting: 2022 American Transplant Congress

Abstract number: 317

Keywords: Allocation, Liver transplantation

Topic: Clinical Science » Liver » 60 - Liver: MELD Allocation*

Session Information

Session Name: MELD Allocation and Large Data

Session Type: Rapid Fire Oral Abstract

Date: Monday, June 6, 2022

Session Time: 5:30pm-7:00pm

Presentation Time: 5:50pm-6:00pm

Location: Hynes Room 313

*Purpose: Liver allocation in the United States was updated on February 4th, 2020, byintroducing the acuity circle (AC)-based model. This study evaluated the early effects of the AC- based allocation on waitlist outcomes.

*Methods: Adult liver transplant (LT) candidates without MELD exception listed between Jan-1-2019 and Sep-30-2021 were assessed. Two periods were defined according to the LT listing date(pre- and post-AC), and 90-day waitlist outcomes were compared. Data was censored if none ofthe waitlist events had occurred before the end of the period. The median transplant MELD scoreof each transplant center was calculated, with centers categorized as low- (<25%ile), mid- (25-75%ile), and high-MELD (>75%ile) centers.

*Results: A total of 11,364 and 15,900 LT candidates in the pre- and post-AC eras wereidentified. Overall, the post-AC era was associated with a higher cause-specific hazard (csHR) of90-day waitlist mortality (csHR=1.21,95%CI=1.09-1.34;P<0.001) and a higher cause-specifichazard of transplant (csHR=1.37,95%CI=1.32-1.43;P<0.001). The disparity in DCD use wasmore prominent in the post-AC era, with lower-MELD centers having a higher proportion ofDCDs used, a higher 90-day cumulative incidence of DCD transplantation, and a higher csHR ofDCD transplant (pre-AC ref. low-MELD: mid-MELD, csHR:0.56,95%CI0.45-0.71 to post-ACcsHR:0.46,95%CI0.38-0.56; and high-MELD, pre-AC csHR:0.09,95%CI0.06-0.15 to post-ACcsHR:0.08,95%CI0.05-0.12; all P<0.001) (Figure 1). Using a structural Bayesian time-series model, the ACpolicy was associated with an increase only in the actual monthly DCD transplants in low-MELD centers (Actual 21, predicted 14; posterior tail-area probability P=0.001), whereas it wasassociated with an increase in both DBD and DCD transplants in mid- and high-MELD centers.

*Conclusions: While AC-based liver allocation may improve waitlist outcomes, regional variation exists in the drivers of such outcomes between centers, including an increased use of DCD LTs in low-MELD centers.

To cite this abstract in AMA style:

Ivanics T, Nagai S, Kitajima T, Shimada S, Shamaa T, Collins K, Rizzari M, Yoshida A, Moonka D, Abouljoud M. Regional Variation in Early Effects of Acuity Circle-Based Liver Allocation [abstract]. Am J Transplant. 2022; 22 (suppl 3). https://atcmeetingabstracts.com/abstract/regional-variation-in-early-effects-of-acuity-circle-based-liver-allocation/. Accessed May 16, 2025.

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