Normothermic machine perfusion boosts liver transplant outcomes, may expand donor criteria
Key takeaways:
- Circulatory death livers preserved for donation with normothermic machine perfusion had the lowest early allograft dysfunction rate.
- This method led to the shortest hospital and ICU lengths of stay.
Normothermic machine perfusion was linked to significant improvements in liver transplant clinical outcomes and reduced hospital resource use, especially among patients who received donation after circulatory death allografts, data show.
“Normothermic machine perfusion (NMP) has shown promise in trials for preserving liver allografts in near-physiologic condition, thereby reducing early allograft dysfunction and its complications,” Michelle C. Nguyen, MD, MPH, transplant surgeon at Mayo Clinic in Phoenix, and colleagues wrote in JAMA Surgery. “However, these trials were limited by strict inclusion criteria for donor and recipient selection and focused primarily on early clinical end points like [early allograft dysfunction], which may limit generalizability.
“Evidence indicates that NMP is particularly beneficial for marginal or donation after circulatory death (DCD) livers, although representation in trials was limited,” they continued. “In this context, definitive conclusions on NMP’s impact on posttransplant outcomes may be premature.”
To compare clinical outcomes of liver allografts preserved with NMP vs. those preserved with static cold storage (SCS), Nguyen and colleagues conducted a retrospective single-center analysis of 1,086 consecutive adults (median age, 60 years; 36.7% women) who received deceased donor liver transplants performed between January 2019 and December 2023 at Mayo Clinic in Arizona.
The researchers stratified the comparison groups based on donor type and preservation approach: donation after brain death (DBD)-NMP (n = 63), DBD-SCS (n = 480), DCD-NMP (n = 279) and DCD-SCS (n = 264).
The primary outcomes of the study were early allograft dysfunction, intraoperative blood transfusions, operating time, posttransplant hospital and ICU length of stay, and readmissions within 30 days and 1 year. Secondary outcomes included acute kidney injury and 1-year graft and patient survival.
Overall, DCD-NMP had the lowest early allograft dysfunction rate (17.5%), followed by DBD-SCS (27.3%), DBD-NMP (36.8%) and DCD-SCS (50%), according to the researchers.
They observed that the DCD-NMP group had the lowest total intraoperative blood component transfusion requirement, with a median volume of 3,400 mL (IQR, 1,900-5,500; P = .003).
Additionally, they found that hospital and ICU lengths of stay were shortest among the DCD-NMP group. DCD-NMP recipients spent a median of 5 days (IQR, 4-7) in the hospital compared with 6 days for the other groups, and a median of 1.5 days (IQR, 1.2-3.1) in the ICU, compared with 2 to 2.3 days for the other groups (both P = .01)
One-year cumulative readmission probability was 86% lower for DCD-NMP compared with DCD-SCS (HR = 0.14; 95% CI, 0.09-0.22) and 53% lower for DBD-NMP compared with DBD-SCS (HR = 0.47; 95% CI, 0.26-0.87).
Among those in the DCD-NMP group, 68.9% had no acute kidney injury compared with 52.6% of those in the DCD-SCS group.
The researchers observed a 78% overall reduction in 1-year graft failure for NMP compared with SCS across both DBD and DCD liver transplants (HR = 0.22; 95% CI, 0.1-0.49). Among those who received DCD allografts, there was an 87% reduction in the risk for graft loss (HR = 0.13; 95% CI, 0.05-0.33).
They also noted that there was a 69% overall relative risk reduction for 1-year mortality with NMP compared with SCS (HR = 0.31; 95% CI, 0.12-0.8).
“This study has broad implications, highlighting two main advantages of NMP: expanding donor acceptance criteria and enabling safe, extended preservation times,” Nguyen and colleagues wrote.
They acknowledged several study limitations, including its observational single-center design, which limits causal inference, and the potential for selection bias.
“Our analysis showed improved clinical outcomes with NMP, but economic studies are needed to evaluate NMP’s effects on total hospital costs, from waitlisting through posttransplant care,” the researchers wrote. “Comprehensive cost-benefit analyses are required to guide clinical strategy in liver transplant strategies, factoring in pretransplant and posttransplant costs, decompensated cirrhosis management and potential savings from earlier offer acceptance.
“Nonetheless, these findings indicate that NMP significantly enhanced DCD liver transplant outcomes and that SCS alone for DCD liver transplant may no longer be justified,” they added.
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