HOPE Perfusion (Hypothermic Oxygenated Perfusion)
HOPE pumps cold, oxygen-rich fluid through a donor liver before transplant. Learn how it helps, who benefits most and what to ask your center.
HOPE is a different perfusion strategy from NMP. Instead of keeping the liver at body temperature (normothermic), HOPE perfuses it with oxygenated solution at cold temperatures — far below body temperature, close to the temperature of ice storage — for a period of time just before transplant.
What HOPE is, in plain words
For decades, donor livers were simply packed in a cold preservation fluid on ice and rushed to the operating room. That is called static cold storage. Cold slows the liver's needs down, but the liver gets no fresh oxygen during that time.
With HOPE, the liver is placed on a machine at the transplant hospital, usually after it arrives. The machine pumps cold preservation fluid, with oxygen added, through the liver's blood vessels. In the best-known trial, livers had two hours of HOPE at the end of cold storage, right before they were transplanted. When both main blood vessels into the liver are used, it may be called dual HOPE (D-HOPE).
How it works
The mechanism is well-described in the literature:
- HOPE is thought to "recharge" mitochondrial function in the donor liver before reperfusion in the recipient. Mitochondria are the tiny power plants inside each cell. In laboratory studies, cold oxygen helped them clear a harmful buildup (succinate) and rebuild their energy stores.
- It has been associated with reduced ischemia-reperfusion injury (the damage that happens when blood rushes back into an oxygen-starved organ) and lower rates of certain post-transplant biliary complications, particularly in DCD (donation after circulatory death) grafts.
- HOPE is shorter-duration than NMP — typically an hour or two of oxygenated cold perfusion at the end of cold storage, not multi-hour normothermic preservation.
- HOPE also gives the team a way to test the liver. While the liver is on the machine, the fluid can be checked for a marker called FMN that is released by damaged mitochondria. An international study of 473 perfused livers found that higher FMN levels predicted which grafts were more likely to fail.
What the research shows
The strongest evidence comes from a randomized trial in livers from DCD donors, published in the New England Journal of Medicine in 2021. Patients were randomly assigned to a liver that got HOPE or a liver kept only in cold storage. Out of 100 people in each group:
- About 6 in the HOPE group developed the bile duct narrowing that DCD livers are known for (non-anastomotic biliary strictures), compared with about 18 in the cold-storage group.
- About 12 in the HOPE group had a sudden drop in blood pressure when the new liver was connected (post-reperfusion syndrome), compared with about 27.
- About 26 in the HOPE group had a slow start for the new liver (early allograft dysfunction), compared with about 40.
Side effects and other problems were similar in both groups.
HOPE has also been studied in older livers from brain-death (DBD) donors. A large European analysis of HOPE-treated livers found good long-term graft survival even though those livers came from older donors on average. These were not randomized comparisons, so they are weaker evidence than the trial above.
How HOPE affects a patient on the list
Some programs use HOPE selectively for DCD livers; others combine HOPE with NMP in sequence. Adoption varies center by center.
If your center offers HOPE, that signals an active interest in protocols designed to safely use a wider range of donor livers (especially DCD). In practice, that can mean:
- More offers that your center can say yes to. Livers that might be declined elsewhere — such as DCD or older-donor livers — may be usable. See extended criteria donors and DCD vs. brain-death donors.
- A more informed yes or no. Testing during HOPE can help the team decide whether a liver is safe for you.
- No change to how offers reach you. Your place in line still depends on your MELD score, blood type and distance from the donor hospital. HOPE affects what your center can accept, not your priority. See how the liver waiting list works.
Questions to ask your transplant team
- "Do you use HOPE or any other machine perfusion? For which livers?"
- "Is HOPE part of your routine care or used within a research study?"
- "Do you use HOPE together with NMP for some livers?"
- "Has machine perfusion changed which offers you accept for patients like me?"
- "If I get a perfused liver, will my care after transplant be any different?"
Common misconceptions
- "HOPE freezes the liver." It doesn't. The fluid is cold, but the liver is not frozen.
- "HOPE and NMP are the same thing." They are different. HOPE is cold and short. NMP keeps the liver warm and working, often for longer, and can be started at the donor hospital.
- "HOPE fixes any bad liver." It reduces some types of injury and helps the team judge the liver, but some livers will still be declined.
- "A perfused liver means a worse liver." Perfusion is often used to make a good liver even safer, not only to rescue a risky one.
Compare programs on our center comparison map.
Sources
- van Rijn R, et al. Hypothermic machine perfusion in liver transplantation — a randomized trial. N Engl J Med. 2021;384:1391-1401. Trial registry record NCT02584283 (ClinicalTrials.gov)
- Hypothermic oxygenated perfusion protects from mitochondrial injury before liver transplantation (EBioMedicine, 2020)
- Assessment of liver graft quality during hypothermic oxygenated perfusion: the first international validation study (J Hepatol, 2025)
- Life expectancy of transplanted livers: HOPE against aging? (Ann Surg, 2025)
- Hypothermic oxygenated liver perfusion: basic mechanisms and clinical application (Curr Transplant Rep, 2015)
Educational only. Not medical advice. Your transplant team has the final word.
