Ex-situ machine perfusion for extracorporeal preservation of livers for transplantation

Evidence-based recommendations on ex-situ machine perfusion for extracorporeal preservation of livers for transplantation in people of all ages. This involves using a machine to give an oxygenated solution to the donor liver until it is transplanted.

# Recommendations
The evidence on ex-situ machine perfusion for extracorporeal preservation of livers for transplantation raises no major safety concerns. However, current evidence on its efficacy is limited in quantity. Therefore, this procedure should only be used with special arrangements for clinical governance, consent, and audit or research.Find out what special arrangements mean on the NICE interventional procedures guidance page.
Clinicians wishing to do ex-situ machine perfusion for extracorporeal preservation of livers for transplantation should:
Inform the clinical governance leads in their NHS trusts.
Ensure that patients given a liver which has had ex-situ machine perfusion understand the uncertainty about the procedure's safety and efficacy, and provide them with clear written information to support shared decision making. In addition, the use of NICE's information for the public on ex-situ machine perfusion for extracorporeal preservation of livers for transplantation is recommended.
Audit and review clinical outcomes of all patients given a liver which has had ex-situ machine perfusion for extracorporeal preservation of livers for transplantation. NICE has identified relevant audit criteria and has developed NICE's interventional procedure outcomes audit tool (which is for use at local discretion).
Clinicians and centres doing this procedure must follow the relevant regulatory and legal requirements of the Human Tissue Authority.
Clinicians should enter details about all patients having this procedure into the NHS Blood and Transplant UK transplant registry.
Further research should report the exact method of perfusion used (such as hypothermic or normothermic), graft survival and the use of marginal grafts.# The condition, current treatments and procedure

# The condition
Liver transplantation is the treatment of choice for patients with end-stage liver disease. It may also be indicated in patients with some types of primary liver cancer. End-stage liver failure can be either acute (for example, from poisoning) or chronic (for example, because of cirrhosis from alcohol-related liver disease, metabolic, autoimmune or infectious conditions). In children, the most common cause of end-stage liver failure is congenital biliary atresia.

# Current treatments
Limited availability of deceased donor livers for transplantation led to the development of techniques that increase the number of recipients who can benefit from 1 available organ. These include split liver grafts (the larger right lobe is usually grafted into an adult and the left lobe into a child) and reduced (segmental) liver grafts.
Living-donor liver transplantation is also an option for patients who are deteriorating clinically while waiting for a deceased donor transplant.

# The procedure
Ex-situ machine perfusion preserves the donor liver outside the body under normothermic or hypothermic conditions. A perfusion machine is used to deliver oxygenated perfusate (which may or may not contain blood depending on the technique employed), supplemented with nutrients and metabolic substrates. The intention is to:
reduce the rate of tissue deterioration that occurs after the liver has been removed from the donor compared with that seen with conventional static cold storage
extend how long the liver can be stored to allow more flexibility in the timing of the transplant operation.Normothermic machine perfusion also allows assessment of donor liver viability and function during preservation. The aim is to improve clinical outcomes for the recipient and to enable otherwise marginal organs (such as those donated after circulatory death, steatotic livers and livers from older people) to be transplanted safely, so increasing the number of livers available for transplantation.
In this procedure, the donor liver is placed in a perfusion machine. The precise configuration of the machine depends on whether normothermic or hypothermic perfusion is being used. Typically, it comprises a reservoir, a pump, an oxygenator, a warming or cooling unit and, for normothermic machine perfusion only, monitoring equipment. Both the hepatic artery and portal vein of the liver may be perfused. For normothermic perfusion, the effluent perfusate is collected and recirculated through the liver. A donor liver can be perfused for several hours, after which it can be implanted into a recipient in the conventional way.