Just four to six hours of normothermic machine perfusion (NMP) assessment enables 70 per cent of currently discarded livers to recover enough to allow successful transplantation, according to the findings of a study published in Nature Communications.
Currently, across the UK, a third of donated livers do not meet desired transplant criteria and are not used. According to the latest NHS Blood and Transplant report, up to 20 per cent of people awaiting a transplant operation died or were removed from waiting lists due to ill health.
A growing proportion of donated livers are coming from high-risk donors with a history of alcohol misuse, obesity or elderly people with comorbidities. Because of lower quality and higher risks, the majority of these organs are not transplanted.
The Viability Testing and Transplantation of Marginal Livers (VITTAL) clinical trial (NCT02740608) used NMP to objectively assess livers discarded by all UK centres meeting specific high-risk criteria.
Thirty-one livers were assessed by viability criteria based on the lactate clearance to levels ≤2.5 mmol/L within four hours.
Viability was achieved by 22 (71%) organs that were transplanted after a median preservation time of 18 hours, with 100 per cent 90-day survival.
During the median follow up of 542 days, four (18%) patients developed biliary strictures requiring re-transplantation.
The authors concluded that viability testing using NMP study enabled successful transplantation of 71 per cent of discarded livers, with 100 per cent 90-day patient and graft survival. However, they added that it does not seem to prevent non-anastomotic biliary strictures in livers donated after circulatory death with prolonged warm ischaemia.