Related Experiment Video
Updated: May 29, 2026
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Ex Situ Normothermic Machine Perfusion of Donor Livers
Published on: May 26, 2015
Donor liver weight in normothermic machine perfusion: Does size really matter?
Braxton Goodnight1, Rachel Kalbfell1, Neeta Vachharajani2
1Department of Surgery, Washington University School of Medicine, St. Louis, MO.
Surgery
|May 27, 2026
Summary
Large livers can be safely transplanted after normothermic machine perfusion, showing similar outcomes to smaller grafts. This suggests expanding donor pool eligibility by using size-universal viability criteria for normothermic machine perfusion.
Area of Science:
- Organ transplantation
- Machine perfusion technologies
- Hepatology
Background:
- Large livers are often excluded from normothermic machine perfusion (NMP) due to concerns about homeostasis and perfusion.
- Uncertainty exists regarding the impact of liver size on transplant outcomes after NMP.
Purpose of the Study:
- To evaluate the impact of liver size on outcomes following normothermic machine perfusion (NMP).
- To determine if larger donor livers can be safely utilized with NMP.
Main Methods:
- Retrospective analysis of 151 liver transplants using NMP (OrganOx metra) over 32 months.
- Livers categorized into small (<1,570 g), medium (1,570-1,870 g), and large (>1,870 g) weight groups.
- Analysis of perfusate metrics during NMP and recipient outcomes.
Main Results:
- Large livers showed higher perfusate transaminase levels during NMP and a trend of elevated post-transplant transaminases.
- No significant differences in 90-day mortality, graft failure, readmissions, or complications were observed across weight groups.
- Large liver size was associated with cradle compression, which in turn was linked to early allograft dysfunction.
Conclusions:
- Normothermic machine perfusion is effective for large livers, yielding outcomes comparable to smaller grafts.
- Higher transaminase levels in large livers during and after NMP do not preclude successful transplantation.
- Size-universal NMP viability criteria can be applied to large livers, potentially expanding the donor organ pool.
