Programmatic Normothermic Machine Perfusion and Association with Liver Transplant Waitlist Outcomes for Patients with Lower Model for End-Stage Liver Disease Score.

Abstract

Background: Normothermic machine perfusion (NMP) may enhance utilization of extended criteria donor livers which might impact waitlist outcomes. Its impact on patients with low MELD scores, who generally face longer waitlist times, has not been studied. This study aims to assess the impact of normothermic machine perfusion (NMP) on waitlist and post-LT outcomes accounting for MELD allocation preference.

Methods: Adult patients listed for liver transplant (LT) at two academic centers within the same enterprise (2/4/2020-12/31/2023) were included (n=1203; pre-NMP=635, NMP=538). Transplant probability and waitlist mortality were analyzed using competing risk analyses.

Results: Patients with listing MELD≤20 demonstrated improved waitlist time (p<0.001), transplant incidence (log-rank p<0.001), and transplant probability (HR=1.48, 95%CI1.29-1.71, p<0.001) with NMP. Open offers (OOs) were more frequent with NMP and lower MELDs. Low-MELD patients demonstrated waitlist cost savings in the NMP era ($36,750 vs. $28,867, p=0.039). Waitlist mortality and post-LT outcomes, survival & costs were not different. Patients with listing MELD>20 demonstrated similar waitlist and post-transplant outcomes and costs in the NMP era. Spline curves show lowest MELD patients (<10points) have experienced the greatest improvement in transplant access.Compared to high-MELD, low-MELD patients in the NMP era had reduced waitlist mortality (log-rank p<0.001) and improved post-LT outcomes: inpatient (p<0.001), 90-day (p=0.002), and 6-month (p=0.04) comprehensive complications index.

Conclusion: Programmatic NMP may help improve transplant access for lower MELD patients. This study also supports early transplantation for patients with low-MELD scores in the modern era.