medwireNews: Normothermic machine perfusion (NMP) preservation of livers due for transplantation is associated with better clinical outcomes and lower hospital resource use than static cold storage (SCS), US study findings indicate.
The benefits were most notable in donation after circulatory death (DCD) allografts. This suggests “NMP may enhance access to [liver transplant] by addressing the challenges historically linked with DCD liver use,” say Amit Mathur and co-investigators from Mayo Clinic Arizona in Phoenix.
Their study included data for all 1086 consecutive adult liver transplants performed between 2019 and 2023. These were divided into four groups according to whether the liver was a DCD or a donation after brain death (DBD), and by the method of liver preservation (NMP or SCS). In all, 279 transplants were classed as DCD-NMP, 264 were DCD-SCS, 63 were DBD-NMP, and 480 were DBD-SCS. The transplant recipients had a median age of 60 years and 63% were men.
The researchers report that DCD-NMP transplants had the lowest rate of early allograft dysfunction (EAD), at 17.5%. This was significantly lower than the EAD rate of 50.0% that occurred with DCD-SCS. The difference between DBD-NMP and DBD-SCS (36.8 vs 27.3%) was not significant, however.
In addition, the DCD-NMP group required significantly lower volumes of intraoperative blood component transfusions than the other three groups. For example, the median red blood cell volume needed was 2100 mL with DCD-NMP compared with a median of 2800 mL in the others.
Median hospital length of stay was significantly shorter in the DCD-NMP group, at 5.0 days, compared with 6.0 days in the DCD-SCS, DBD-NMP, and DBD-SCS groups. The corresponding median lengths of stay in intensive care were 1.5, 2.1, 2.0, and 2.3 days, with the difference again statistically significant between DCD-NMP and the other groups.
Mathur and team also found that the 1-year cumulative readmission probability was a significant 86% lower for DCD-NMP versus DCD-SCS (10.0 vs 51.1%), and a significant 53% lower for DBD-NMP versus DBD-SCS (17.5 vs 34.1%).
Among the secondary outcomes measured, DCD-NMP recipients had a significantly lower rate of acute kidney injury events than DCD-SCS recipients (31.1 vs 47.4%).
Overall, the risk for 1-year graft failure was a significant 78% lower with NMP than with SCS across both DBD and DCD liver transplants. When the data were further analyzed by graft type and preservation method, NMP was associated with a significant 87% decrease in graft failure among patients receiving DCD allografts.
Conversely, there was no significant difference between the two preservation methods in graft failure risk for patients given DBD allografts.
For all-cause mortality at 1 year, there was a 69% relative risk reduction with NMP versus SCS overall, but no significant differences by graft type.
The investigators note that the benefits of NMP were observed despite increased donor age, donor BMI, national sharing, and recipient age in the DCD-NMP group.
They conclude: “This study has broad implications, highlighting 2 main advantages of NMP: expanding donor acceptance criteria and enabling safe, extended preservation times.”
Mathur et al add that their findings suggest that “SCS alone for DCD [liver transplant] may no longer be justified.”
They say: “NMP not only enhances graft viability but also sets a new standard in clinical outcomes, positioning it as an indispensable tool in modern [liver transplant] practice.”
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