Cywes, Claire

Background and Objectives: Normothermic regional perfusion (NRP) is an effective technique to improve recipient outcomes. However, no valid methods for determining liver viability exist. Identifying relevant biological markers with clinical correlation to liver viability and recipient clinical outcomes is imperative to improve decision-making. Materials and Methods: Fifty-four donors undergoing NRP and their recipients were included. FMN was measured at the start, 1 h, and end of NRP. Lactate was measured at the start, 30, 60, and 90 min of NRP. Primary outcomes were early allograft function using the early allograft dysfunction (EAD) criteria and the model for early allograft function (MEAF). Secondary outcomes included the association with donor warm ischemia time (DWIT), stratified by 30 min. Spearman’s rho assessed correlations. Results: Forty (74%) livers were transplanted, with 5 (12.5%) recipients developing EAD and the mean MEAF score was 3.13 (1.49). FMN at all time points was significantly greater in the EAD group compared to the non-EAD group and was significantly correlated with the MEAF score (Peak FMN: rho = 0.507, p = 0.001). FMN during perfusion did not differ between DWIT < and ≥30 min. Lactate levels were similar across all groups and did not discriminate for adverse allograft outcomes. However, lactate levels during perfusion were higher in the DWIT ≥ 30 min group. Conclusions: These findings suggest that during NRP, elevated FMN, but not lactate, is associated with early allograft function.

Multi-listing (ML) increases the odds of transplantation compared with single-center listing. However, not all patients have equivalent access to ML. The recent allocation policy change prioritized distance from the donor hospital in an attempt to decrease geographic disparities. This study assessed access to liver transplant (LT) given ML practices before and after the acuity circles policy change. United Network for Organ Sharing data were queried for LTs between January 1, 2016, and November 1, 2024. Patients were grouped by listing at one versus multiple centers and by acuity circle era (ACE). Cohort characteristics and comparisons were described using chi-square and Wilcoxon rank tests. Multivariable logistic regressions and propensity score match (PSM) were performed to assess associations between ML and LT. The final cohort consisted of 105,030 patients; 4084 (3.9%) were multi-listed. Racial/ethnic minority groups, less educated, and publicly insured candidates were less often multi-listed. ML was positively associated with LT in all analyses (overall: OR=1.180, p <0.001; PSM: OR=1.164, p =0.001; pre-ACE: OR=1.127, p =0.015; post-ACE: OR=1.218, p <0.001). Education, race/ethnicity, and insurance type were also associated with LT across all analyses. ML patients were more often transplanted at their primary center with a significant increase in primary center LT post-ACE (53.4% vs. 63.4%, p <0.001). ML and LT had a positive correlation. There was a negative association between minority groups and ML as well as LT. Although acuity circles decreased geographic disparities, they did not change ML accessibility across candidates.

ABSTRACT During normothermic regional perfusion (NRP), lactate is the most commonly used liver viability marker. Lactate production from pyruvate breakdown in erythrocytes is not suspended during pRBC storage. By transfusing blood at a variety of stored ages, variable amounts of lactate are added to the NRP circuit and may influence serial lactate measurements. Sixteen DCD donors undergoing NRP were enrolled in a prospective study. Samples were drawn from pRBC bags prior to use in the NRP circuit and were tested for lactate values. Lactate values of the NRP circuit perfusate were also assessed Q15 min. Lactate values of the pRBCs varied from 4.4 mmol/L to >20 mmol/L and were strongly correlated with the age of the stored blood ( r 2 = 0.74). Donors in which the pRBCs were > = 20‐days from expiration (Newer Blood group) had a significantly lower lactate at 60 min of NRP compared to donors in which pRBCs were <20 day from expiration (Older Blood group) (4.0±2.0 mg/dL vs. 6.3±2.3 mg/dL; p = 0.048). If the lactate is not decreasing as anticipated, transfusion of older pRBC should be entertained as one possible explanation. In cases where the liver seems acceptable for transplantation, additional lactate testing with longer time on NRP or sequential NRP/NMP should be considered in lieu of declining the liver outright.