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Innovation
A new liver perfusion machine – the first of its kind in Africa – is making organ transports much safer.
For a liver to be successfully transplanted, it has to stay alive and healthy outside the body. A perfusion machine does exactly that, keeping it supplied with blood and oxygen until it reaches its new home. Professor Jerome Loveland, surgeon and Head of Solid Organ Transplantation at Wits Donald Gordon Medical Centre (WDGMC), explains how this lifesaving technology works.
The risks of traditional donor liver preservation
In preparation for traditional liver, heart, lung or kidney organ transplants, organs are removed from a donor and then perfused with cold preservation fluid, says Professor Loveland. “You then essentially store the organs in ice to completely reduce any metabolic demand on them.”
The drawback is the cold ischaemic time, the window in which the organ stays viable before its chances of working properly drop sharply. For a liver, that window is eight hours or less, which makes transplants far more difficult, especially when the organ must be flown or driven between cities.
The health of the donor is also a major factor in determining the success of a liver transplant, Professor Loveland adds. There’s always a risk that the liver won’t work well or at all. If it comes from a healthy, young person, however, the impact of removal is quite low, and you can transplant it with relative safety.
“The risks of the liver graft not working are much higher if you get what’s known as an extended criteria donor, where there are multiple other risk factors. The donor may be older than 55 or may have been in ICU for a prolonged period. The patient cost here is potentially enormous – if the organ doesn't work, they’ll need a retransplant, without which they will die. If the liver takes a while to work, that means medical complications, as well as a high cost of care.”
How the liver perfusion machine boosts liver viability
The liver perfusion machine reduces all these risks, Professor Loveland says. As soon as the liver arrives at the hospital, it is prepared and placed onto the perfusion machine, where it’s stored at a slightly higher temperature than it would be during regular perfusion.
The liver simultaneously undergoes two processes in the machine to boost its efficacy. “The machine provides oxygen to the liver while it’s being stored. It also flushes out bad metabolites produced due to the liver being removed from the body.
“These processes resuscitate and preserve the liver so it can be stored for longer, essentially up to 24 hours. This also means the risk of liver graft dysfunction in the recipient is significantly lower”.
The extra time also takes the pressure off the transplant team – they can find the right recipient, get them admitted to hospital, and ensure the liver is put to the best possible use.
The perfusion machine means the liver works significantly better, with far less risk to the recipient and a reduced cost of care.
Addressing South Africa’s donor liver shortage
Professor Loveland explains that liver perfusion machines have become the standard of care in high-income countries because of the profound difference they make to transplants and patient outcomes. But until now, the technology has not been adopted anywhere in Africa. “Its introduction to WDGMC is groundbreaking from an African perspective,” he says.
The machine also makes a big difference in addressing South Africa's shortage of donor organs. "Due to this shortage, you're obligated to use just about any organ, within clinical criteria, as it might be a recipient's only chance to live." With the machine, however, doctors now have far more information about organs that would previously have been considered borderline.
“You can't test the function of the liver, but you can look at the flow and pressure dynamics generated by the perfusion machine, which gives you a good idea of how that liver is responding,” explains Professor Loveland.
If all those parameters are trending in the right direction and the donor's liver function tests are acceptable, that's a good sign the liver will work, he says. “The perfusion technology allows us to use around 10 to 15% more organs than we used to before.” That means some donor livers that would previously have been turned down can now be used.
Improving patient outcomes
The new technology has a profound impact on patient outcomes, says Professor Loveland.
“From a clinical perspective, the incidence of complications was significantly higher with an extended criteria liver, which also translates to a cost. So, by perfusing these livers, we’re converting them from an extended criteria liver into a good or normal criteria liver, effectively preventing complications like early graft dysfunction and even death.”
To date there have only been two cases using this technology at WDGMC, but both have had phenomenal outcomes, he adds. “While our data is still subjective, the machine has already transformed the liver transplant practice.”
He expects this trend to continue, revolutionising patient outcomes and significantly increasing the number of livers available for transplantation.
“The next step is to do normothermic perfusion, which allows doctors to biochemically assess whether the liver is working. That way, if you put a liver that you would have otherwise discarded on the machine and it works, you can transplant it into the patient, knowing that it will work.”