DCD liver transplants in PSC

Diagram of liver summarising main findings JnlHepatologyPSC varies from patient to patient, and many go on to live normal lives. Others however, may be affected by symptoms such as fatigue, itch and abdominal pain. Some individuals do unfortunately develop progressive disease, and liver transplantation is the only life saving  treatment at this stage.

Although PSC is a rare disease, it is now the reason for more than 11% of all liver transplant operations performed in the UK1 - second only to alcohol-related liver disease and liver cancer.

 

Best use of available organs

Thankfully, the number of transplant operations being performed year-on-year are increasing, together with a rise in donor registrations. However, the supply of suitable donor organs does not meet demand. Researchers are thus constantly looking for ways to make the best possible use of available organs.

 

DCD vs. DBD organs

The most common source for a new liver is one retrieved from an individual whose heart is still beating, but brain has ceased to function - termed organ donation after brain death2 (DBD). The reason for DBD liver being ideal is because the liver is receiving an adequate supply of blood, nutrients and oxygen up until it is taken for transplantation. Less commonly, liver transplantation may have to be performed using an organ donated after circulatory death3 (DCD). Historically there has been a perception that post-transplant outcomes are worse using DCD livers, given that the organ would experience a period without an adequate blood supply, effectively starved for some time before it is retrieved. As a result, early experiences of DCD livers particularly in very sick individuals, raised concerns over transplant-related bile duct problems, kidney injury, and poor overall graft function. These anxieties are particularly relevant for patients with PSC who are often quite young, and have lived with bile duct disease for many years. Consequently, many liver transplant centres across the world have avoided DCD livers in PSC liver transplantation, despite the fact some patients die on the transplant waiting list.

Nevertheless, a study published this week from researchers at University of Birmingham (Trivedi et al., Journal of Hepatology; in press4) evaluated outcomes of over a decade of liver transplantation, across two groups of PSC patients: those receiving DBD livers vs. DCD transplants.  The investigators were able to show that with careful patient and donor organ selection, DCD transplantation in PSC achieves very similar outcomes to those receiving DBD livers.

Highlights from the study included:

  • No significant differences between DCD and DBD groups in terms of:
    • operation times
    • blood transfusion requirement
    • number of days spent in the intensive care unit
    • total hospital stay following liver transplant
    • risk of acute kidney injury
    • problems of the transplanted liver blood supply (hepatic artery thrombosis)
    • overall patient survival
    • overall graft survival / need for a 2nd liver transplant
  • A higher incidence of hepatic artery thrombosis in PSC patients who have IBD in both groups (emphasising the need for good colitis assessment and control)
  • An increased risk of very early transplant-related bile duct complications in the DCD group, but no difference in the development of biliary complications overall

It’s important to understand that whatever the underlying liver disease, DCD liver transplant recipients tend to have a higher rate of bile duct problems in their first year, and PSC is no exception. The rate of graft loss in PSC was significantly greater compared to non-PSC patients, but looking at PSC patients alone, DCD vs DBD transplantation did not adversely affect overall patient survival or graft survival rates, thus the conclusion that DCD transplants could be a viable option for selected PSC patients in the future.

The use of DCD livers in transplantation is a developing practice, and longer term outcomes have yet to be determined. Similarly, while the transplant centre at Birmingham is one of the busiest in the UK, this study only represents experience at one centre, and the authors acknowledge the importance of external, independent validation of their findings. However, given the complexity of PSC, and with the forthcoming changes to allocation policy in liver transplantation in the UK, continuing evaluation of risks and post-transplant outcomes for PSC patients is critical.

 

Reviewed by Dr Palak Trivedi 13 July 2017


Notes

1 NHSBT Annual Report on Liver Transplantation 2015/16 (published Sep 2016) available from www.odt.nhs.uk/statistics-and-reports/organ-specific-reports/ (accessed 13 July 2017)

2 Donors after brain death (DBD) are defined by NHSBT as patients for whom death was confirmed following neurological tests and who had no absolute medical contraindications to solid organ donation. Last year, the number of liver donors after brain death was 747, leading to 738 transplants5.

3 Donors after circulatory death (DCD) are defined by NHSBT as patients who had treatment withdrawn and death was anticipated within four hours, with no absolute medical contraindications to solid organ donation. Last year, the number of liver donors after circulatory death was 294, leading to 208 transplants5.

4 Trivedi PJ, et al. (in press) Clinical outcomes of donation after circulatory death liver transplantation in primary sclerosing cholangitis. Journal of Hepatology doi:10.1016/j.jhep.2017.06.027 (accessed 13 July 2017)

5 NHSBT Annual Activity Report 2016/7 (published July 2017) available from www.odt.nhs.uk/statistics-and-reports/annual-activity-report/ (accessed 13 July 2017)

image courtesy of authors (Journal of Hepatology)