The number of livers available for transplant could be increased significantly using a new technology that preserves the organs at body temperature.
In a paper in the journal Nature, Oxford-based OrganOx has published the findings of a randomised, multinational clinical trial, in which transplanted livers were shown to function better when preserved with its metra device.
When a liver is donated for transplant, it is stored in an ice box. This slows the liver’s metabolism, helping to preserve it until it can be transplanted. However, the organ continues to deteriorate every second it is preserved on ice, limiting the length of time an organ can be stored to between six to nine hours, according to Andy Self, commercial director at OrganOx.
“When the liver is in an ice box, the surgeon has very little information to go on, he can’t assess the function of the liver, all he can do is look at the donor history and make a judgement call about whether to transplant it,” said Self.
This decision is particularly important in liver transplants, where in the event of a complication surgeons have just 24 hours to find an alternative donor organ or the patient will not survive, he said.
“For that reason, liver transplant surgeons are rightly quite conservative about the organs they transplant,” Self explained. “That results in quite a large number of the organs that are retrieved for transplant being discarded.”
The metra device maintains the liver at normal body temperature and provides it with oxygenated blood, nutrients and medication. This reduces the risk of tissue injury when blood supply is returned to the organ.
The device also continuously monitors the liver while it is being preserved, measuring blood flow, pressure, blood gasses and bile production, to give the surgeon information on how the organ is performing.
In the trial, funded by the European Commission, 220 livers were transplanted after being randomly chosen for preservation in either an ice box or using the metra device. The researchers found the metra-preserved livers functioned better, and this benefit was most pronounced in the most “marginal” donor livers.
There were also fewer discarded organs, resulting in 20 per cent more transplanted livers.
In this way the technology could allow donor livers that would currently be discarded to be considered for transplant, increasing the number of available organs.