The study involved monitoring 156 transplant patients, all of whom had received a donor organ from a victim of cardiac arrest. Half of the donor livers were flushed with oxygen-enriched liquid for two hours outside the body via machine perfusion. The other half of the donor organs were stored on ice. This study examined the incidence of biliary complications in patients after the transplant. During a transplant procedure, it is inevitable that a liver must spend some time outside the body. The liver’s bile ducts are very sensitive to the damage that this causes to the liver. Damage to the small blood vessels leading to the bile ducts is common and in turn, increases the chances of biliary complications after the transplant.
These complications occur in approximately a quarter of all patients who undergo a liver transplant. Three to four months after the operation, they develop a fever, jaundice and inflammation of the bile ducts due to the scarring caused by oxygen deprivation in the damaged bile ducts. This often requires extra treatment and more procedures. In some cases, the complications can only be remedied by a second transplant. Biliary complications are the main reason that donor livers are lost. The risk is higher for livers donated after cardiac arrest than for livers donated after brain death.
The study shows that the patients who received a liver that had been flushed by a perfusion machine were far less likely to develop biliary complications. Only 6% of the patients in this group developed biliary complications, compared with 18% of the patients in the other group. Head of the research programme Robert Porte is very enthusiastic about this result: ‘Treating donor livers with oxygen-enriched liquid in a perfusion machine protects them from the injuries and inflammatory reactions that occur when the liver is again supplied with blood after having been temporarily deprived of oxygen. We suspected that this would also help to prevent biliary complications after the transplant. The study showed that we were right. It is the first study in the world to prove the effectiveness of this type of machine perfusion.’
As the risk of complications in livers that are donated after cardiac arrest is greater than that in livers donated after brain death, some transplant centres are hesitant to accept donor livers of this kind. Porte: ‘The USA in particular transplants fewer livers harvested after cardiac arrest than countries such as the Netherlands, Belgium and the UK. This machine perfusion technique not only prevents complications after transplant, but hopefully, it will also allow us to accept more donor livers that have been harvested after cardiac arrest.’
The UMCG has been running an Organ Preservation & Resuscitation unit since 2015. In this unit, donor organs such as livers, lungs and kidneys are treated with an oxygen-enriched liquid and nutrients in perfusion machines to prepare them for transplant. The new perfusion techniques not only mean that organs can be stored more efficiently, but also that they can be enhanced and tested immediately before they are transplanted. As a result, more organs can be made suitable for transplant. In the past, the UMCG successfully transplanted ‘unsuitable’ lungs after optimizing them in a perfusion machine.
