Researchers try new ways of preserving more hearts for transplants

Hamilton Spectator

5 days ago

WASHINGTON (AP) — Two university hospitals are pioneering new ways to expand lifesaving heart transplants for adults and babies — advances that could help recover would-be heart donations that too often go unused.
The new research aims to overcome barriers for using organs from someone who dies when their heart stops. Called DCD,
or donation after circulatory death
, it involves a controversial recovery technique or the use of expensive machines.
Surgeons at Duke and Vanderbilt universities reported Wednesday that they've separately devised simpler approaches to retrieve those hearts. In the New England Journal of Medicine, they described successfully transplanting hearts to a 3-month-old infant at Duke and three men at Vanderbilt.
'These DCD hearts work just as well as hearts from brain-dead donors,' said Vanderbilt lead author Dr. Aaron M. Williams.
How hearts are saved for donation
Most transplanted hearts come from donors who are brain dead. In those situations, the body is left on a ventilator that keeps the heart beating until the organs are removed.
Circulatory death occurs when someone has a nonsurvivable brain injury but because all brain function hasn't ceased, the family decides to withdraw life support and the heart stops. That means organs can spend a while without oxygen before being recovered, a time lag usually doable for kidneys and other organs but that can raise questions about the quality of hearts.
To counter damage and determine whether DCD organs are usable, surgeons can pump blood and oxygen to the deceased donor's abdominal and chest organs — after clamping off access to the brain. But it's ethically controversial to artificially restore circulation even temporarily and some hospitals prohibit that technique, called normothermic regional perfusion, or NRP.
Another option is to 'reanimate' DCD organs in a machine that pumps blood and nutrients on the way to the transplant hospital. The machines are expensive and complex, and Duke's Dr. Joseph Turek said the devices can't be used for young children's small hearts — the age group with the most dire need.
New ways of preserving hearts
Turek's team found a middle ground: Remove the heart and attach some tubes of oxygen and blood to briefly assess its ability to function — not in a machine but on a sterile table in the operating room.
They practiced with piglets. Then came the real test. At another hospital, life support was about to be withdrawn from a 1-month-old whose family wanted to donate — and who would be a good match for a 3-month-old Duke patient in desperate need of a new heart. The other hospital didn't allow the controversial NRP recovery technique but let Turek's team test the experimental alternative.
It took just five minutes to tell 'the coronary arteries are filling well, it's pink, it's beating,' Turek said. The team promptly put the little heart on ice and raced it back to Duke.
Vanderbilt's system is even simpler: Infuse the heart with a nutrient-rich, cold preservative solution before removing it from the donor's body, similar to how hearts from brain-dead donors are handled.
That 'replenishes the nutrients that are depleted during the dying process and helps protect it for transport,' Williams explained, adding that Vanderbilt has performed about 25 such transplants so far. 'Our view is you don't necessarily need to reanimate the heart.'
More donated hearts are needed
There's a
huge need
for more transplantable hearts. Hundreds of thousands of adults suffer from advanced heart failure, yet many are never even offered a transplant because of the organ shortage.
Every year about 700 children in the U.S. are added to the transplant list for a new heart and about 20% die waiting. Turek said infants are at particular risk.
Last year, people whose lives ended via circulatory death made up 43% of the nation's deceased donors — but just 793 of the 4,572 heart transplants.
That's why many specialists say finding ways to use more of those hearts is crucial. The new studies are small and early-stage but promising, said Brendan Parent of NYU Langone Health, who directs transplant ethics and policy research.
'Innovation to find ways to recover organs successfully after circulatory death are essential for reducing the organ shortage,' he said.
If alternatives pan out, 'I absolutely think that cardiac programs will be thrilled, especially at hospitals that have rejected NRP.'
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