UK doctors pioneer use of 'heart in a box' transplant technique in children
NHS doctors have pioneered the use of a “dead” heart transplant technique – previously deemed suitable only for adults – in children, saving the lives of six young patients last year.
Surgeons typically use for transplants hearts donated by patients who are declared brain stem dead but whose hearts are still beating. Retrieving the hearts of patients who have suffered cardiac death (which are far more common than brain stem deaths) is considered too risky a prospect.
Marius Berman, a consultant cardiothoracic transplant surgeon at Royal Papworth hospital (RPH) in Cambridge, said that after cardiac death the heart is “like an inflated balloon. So there is no way that we can assess if the heart is working well … that’s why it won’t be safe to retrieve the heart because we wouldn’t know how it functions.”
Previously, hearts were transported for intended recipients in sterile iceboxes. However, a “heart in a box” machine – called an Organ Care System (OCS), developed by the American company TransMedics – was engineered to emulate the human body, keeping the heart warm, beating and pumping blood so it is healthy for transport to the recipient. The idea behind the machine was to allow for the organ to be transported across long distances.
In 2015 doctors at RPH pioneered the use of the machine to revive hearts from donors who had suffered cardiac death. By reanimating those hearts using the machine, doctors could assess whether the organ was salvageable for transplantation.
The concept worked, and since then, said Berman, “we have essentially doubled our heart transplant activity, every single year”. At some point the new method overtook the traditional way of organ donation after brain death, he added, while health outcomes for patients have remained constant.
Now a collaboration between RPH, whose team retrieves the heart, and Great Ormond Street hospital in London, whose team implants the organ, has pioneered the first use of the technique in paediatric transplantation.
Across the UK, the average wait for an adult who needs a heart transplant is nearly three years. Patients who need
hearts typically exceed the number of available donor hearts, and children face even longer waiting times, given the right organ size must be found and the consent rate for child organ donation is relatively much lower.
Great Ormond Street has 24 children waiting for a heart transplant, and between 2014 and 2019 the average waiting time was 282 days.
“Transplant waiting times are significantly lower at RPH than the national average, not because we’re better surgeons,” said Berman. It was because the new approach saved time and money, he said.
The first child to receive a transplant based on the new approach was 15-year-old Anna Hadley, who was diagnosed with restrictive cardiomyopathy in 2018.
“We always tried to stay positive but we understood the facts – there was a lack of suitable donors and around 40% of children waiting for heart transplant never receive one. It made the more than 20 months spent on the transplant waiting list incredibly difficult,” said Anna’s dad, Andrew Hadley. “Five days after the transplant, Anna was walking up and down the corridors chatting away and high-fiving staff. It was incredible.”
At the moment the technology is limited to donors who weigh at least 50kg, but the two hospitals are working on a new machine that will enable donation from even infants, which could usher in an era of transplantation for babies and young children where donors are the most scarce. A prototype is ready and the doctors expect to start using the machine by the end of this year.
The per-use cost of the existing OCS machine is about £50,000, but in effect it costs less than having heart patients waiting for organs. Every day in the UK there are between 30 to 40 adults on the urgent transplant list. Each day in intensive care costs £2,500, said Berman. “That means that every single day [it is costing the NHS] … £70,000 to £90,000 for patients to wait in the hospital.
”Ultimately, this work still relies on families having conversations about organ donation wishes, said Jacob Simmonds, consultant cardiologist and transplant physician at Great Ormond Street, “and then, of course, the bravery to consider making this precious, lifesaving gift at a time of unimaginable tragedy.”