Guidance assessment consultation document for In-situ abdominal normothermic regional perfusion to preserve donor livers during retrieval for transplantation after controlled circulatory death

Liver transplant is a treatment option for people with end-stage liver disease (for example, because of alcohol-related liver disease or metabolic, autoimmune or infectious conditions), liver cancer or acute liver failure. Between April 2024 and March 2025, 785 whole-liver transplants were done in the UK. At the end of March 2025 there were 584 adults on the UK's active liver transplant list (NHS Blood and Transplant annual report on liver transplantation, 2025).

Most livers are donated as whole organs and come from donors who have died from circulatory or brain death. Between April 2024 and March 2025, in the UK 433 adult livers were donated from donors who died from circulatory death (NHS Blood and Transplant annual report on liver transplantation, 2025). Not all these livers were able to be used for transplants.

This guidance focuses on livers donated after controlled circulatory death. This is when a person's organs are retrieved for transplantation following planned withdrawal of life sustaining treatments.

A donor liver for transplantation is usually preserved using static cold storage. This involves immediately flushing the donor liver with cold organ-preservation solution and then placing it in a sterile bag in a cold-storage icebox for transport. This process is done by a specially trained team and aims to minimise ischaemic damage to the donor liver. Before a liver is transplanted it can be stored in an icebox for about 8 to 12 hours. The storage time depends on a number of factors, including the time taken for retrieval.

Normothermic machine perfusion is an ex-situ preservation technique. The recovered liver is placed on a mechanical circuit that circulates oxygenated, blood-based perfusate at body temperature. NICE HealthTech guidance on ex-situ machine perfusion for extracorporeal preservation of livers for transplantation recommends it for use with special arrangements. The procedure is a recognised clinical option within the NHS to preserve livers donated after controlled circulatory death.

There is a shortage of organs available that are suitable for transplantation in the UK. There is also a high demand for donor livers. This demand is rising because of an increasing prevalence of chronic liver diseases in the general population. The shortage of suitable donor livers can result in longer waiting times for people on the waiting list for a liver transplant. This is associated with complications, worsening symptoms and death. Two-year follow-up data of people registered on the waiting list between April 2022 and March 2023 indicated that 11% died before receiving a liver transplant and a further 11% were still waiting (NHS Blood and Transplant annual report on liver transplantation, 2025).

Livers from donors who have died from controlled circulatory death are at risk of ischaemic damage. This damage occurs because blood flow to the liver is interrupted when the donor dies. Further ischaemic damage can occur when the liver undergoes a period of static cold storage before transplantation. The damage becomes irreversible during the cold-storage process. As a result, livers retrieved from donors who have died from controlled circulatory death can be unsuitable for transplantation. In the UK, many donor livers with ischaemic damage are not used in transplants because of the risk of worse transplant outcomes and uncertainty about liver viability. This includes livers that are declined either before or after retrieval. Between April 2024 and March 2025, out of 727 livers donated after controlled circulatory death, 309 were transplanted. Therefore, 58% of the donated livers were not used for transplantation (NHS Blood and Transplant annual report on liver transplantation, 2025).

In-situ abdominal normothermic regional perfusion can allow the liver to recover from existing ischaemic damage inside the donor's body before the liver is retrieved, cooled down and stored for transport. This prevents further ischaemic damage during the storage process. The procedure can improve the quality of livers retrieved from donors who have died from controlled circulatory death and increase the number of livers suitable for transplantation.

NICE did a rapid review of the literature on the efficacy and safety of this procedure. The evidence included 3 systematic review and meta-analyses and 5 observational comparative studies. It is presented in the summary of key evidence section in the interventional procedures assessment report. Other relevant literature is in the appendix of the assessment report.

The professional experts, patient experts and the committee considered the key efficacy outcomes to be:

• primary non-function

• early allograft dysfunction

• graft survival and graft loss

• transplant utilisation and discard rate

• recipient survival.

The professional experts, patient experts and the committee considered the key safety outcomes to be:

• recipient hospitalisation

• biliary complications

• ischaemic cholangiopathy

• hepatic artery thrombosis

• renal complications

• procedure-related adverse events.

Four commentaries from people who received livers that were preserved during retrieval using in-situ abdominal normothermic regional perfusion, and 121 commentaries from people who have had or are waiting for a liver transplant, or their carers, were discussed by the committee.

In-situ abdominal normothermic regional perfusion should be done by teams with specific training and specialist equipment. Not all centres currently have access to this, so there could be regional differences in services.

The procedure enables transplant teams to objectively assess liver function before they retrieve the donor liver. This means that acceptance of the liver is not based on subjective assessment alone. It also means that livers that would not previously have been considered suitable for donation could be considered suitable based on objective liver function tests. So, the procedure could reduce variation in practice and improve equity of access to donor livers.