OrganOx metra for liver transplant

Level of innovation

One expert advised that there are 3 devices on the market that provide normothermic machine perfusion (NMP). All experts reported that this device is in use in all UK liver transplant centres. It is established practice at some sites and more novel at others. There are also a range of uses of the device across these sites, depending on the financial support in place. The technology can be used either as an addition to, or instead of, existing standard care, depending on its use in back-to-base mode or continuous perfusion. One expert felt that its role was in addition to standard care and would not be needed for good quality livers with straightforward logistics.

Experts reported that the technology could replace current standard care to varying extents. This included assessing less than ideal livers to support optimum outcomes, after standard care on arrival at the site where the person having the transplant is, and potentially throughout the process, given the increased number of extended criteria grafts and organ use possible.

Potential patient impact

Three experts reported that the ability to assess the function of the organs may reduce discarded livers, increasing available organs for people on the waiting list. They highlighted that the increased use of livers would result in shorter waiting times and reduced waiting list mortality. One expert reported that this opportunity for functional assessment also means the livers that are appropriate may have improved outcomes and reduced complications for people after transplant.

Three experts reported multiple benefits to the extended preservation time that the OrganOx metra offers. The flexibility in arranging the transplant allowed a more prolonged donor assessment. Experts reported that this may result in reduced call ups and cancellations for patients, improving their experience. Two experts highlighted that this flexibility in timings could also reduce inequalities in access to machine perfusion technologies, with particular benefit to people who live further away from transplant centres.

Three experts reported that the technology could benefit viability of donor organs from older donors, donors with steatotic (fatty) livers, donors with concerning histories, or after circulatory death. All experts highlighted that it would particularly benefit people with complexities, including those with fulfilment liver failure, those who were very unwell (such as those with haemodynamic instability) and people having re-transplant.

Potential system impact

Experts agreed that the technology could change the current pathway and improve clinical outcomes. Three experts highlighted the increased upfront costs needed to set the device up in the system, including support, training and staffing for organ perfusion and monitoring on the machine. Also, 1 expert highlighted the need for formal training protocols to be in place. This is particularly important when considering prolonged preservation (up to and beyond 24 hours) and the supervision and troubleshooting that may be needed with this.

One expert reported that the increased flexibility meant that the logistics of transplants were improved and provided the option of elective surgeries to be arranged. One expert highlighted the benefit, in particular during the pandemic, of allowing livers to be stored for longer while testing and admission is arranged for people.

All experts emphasised the system benefit of increased donor liver rates. One expert reported that using the device means that livers can be offered to people who may otherwise have had long hospital stays without transplant, as well as better early function being reported, which may reduce length of inpatient stays and re-transplantation rates.

General comments

Three experts highlighted that a full cost economic analysis is still needed to see the true effect on the pathway, summarising how much the existing healthcare burden is offset by adopting this technology. This should include the reduction in hospital costs of those on waiting lists, the increased number of transplants done, the impact on waiting list mortality, the development of complications and the follow-up costs.

Experts described various gaps in knowledge that they reported would benefit from further data. These included having information to reduce uncertainty in safety and efficacy, in particular highlighting some noted effects with the use of the device, as reported in Richards et al. (2021) and Hann et al. (2020). Data to inform the optimum perfusate on the machine is yet to be identified, as is further data to inform the accepted criteria for viable livers, clarifying which organs may benefit from functional assessment. Another expert felt they would benefit from a better understanding of quality of life after transplant.

Experts also highlighted that the analysis of its use alongside, and compared with, other evolving techniques would be beneficial. This should include regional perfusion (in donation after circulatory death) and understanding the risks and benefits of hypothermic oxygenated machine perfusion (HOPE) in relation to normothermic perfusion of the OrganOx metra.

Expert commentators

The following clinicians contributed to this briefing: