The shortage of organs for cardiac transplants represents a major medical challenge. In France, 411 cardiac transplants were made in 2022, insufficient number against the 2 candidates for only 1 graft available. The situation is particularly critical in children: 18 children awaiting transplants died for lack of a graft compatible in 2023. Faced with this dramatic situation, two teams of American surgeons have just taken a decisive stage by developing innovative techniques which could radically transform the landscape of cardiac transplantations.
The major challenge for pediatric transplants
Heart transplantation remains one of the most complex challenges of modern medicine. Traditionally, the majority of grafts come from patients in brain deaths whose heart continues to beat. However, these cases remain insufficient to meet growing demand, especially in younger patients.
Surgeons can also recover hearts after cardiac arrest, but this approach has considerable obstacles. Existing methods require either costly extracorporeal machines – unusable for donors under 40 kg – or direct resuscitation in the donor’s body, raising important ethical questions.
These ethical concerns are not trivial. Cardiac resuscitation in the body could theoretically modify the official cause of death, from circulatory death to brain death. Even more disturbing, this procedure could restore blood flow to the brain, despite the use of clamps to block this circulation.
A technical breakthrough for children’s hearts
It is in this context that Joseph Turek, a pediatric heart surgeon at Duke University, and his team have developed an ingenious solution. Their technique consists in reviving the heart entirely out of the body, thus bypassing the previous ethical dilemmas.
The process is based on a sophisticated but relatively simple system: oxygenated blood is injected into the heart via a tube connected to the aorta, then drained by a vent placed in the left ventricle. This blood is then collected, reoxygenated and reinjected into a closed circuit, now the organ alive the time necessary for transplantation.
After conclusive tests on 12 -week porcelets, the team crossed the head of the first human test. The case reported in the New England Journal of Medicine describes the successful transplant of the heart of a one -month -old baby who died around a three -month infant. Three months after the intervention, the recipient’s heart worked perfectly, without any sign of rejection.
This advance could allow up to 100 additional pediatric cardiac transplants each year in the United States. Beyond its clinical impact, this technique has the advantage of being economically accessible, not requiring the expensive equipment of traditional extracorporeal methods.
Credit: ISTOCK
Crédits : Danchai Nortown/istock
A complementary approach to adults
At the same time, John Trahanas’ team at the Vanderbilt University Medical Center has developed a different but just as promising approach. Their technique consists in maintaining the heart in a controlled state of rest rather than reviving it.
The procedure implies the clamping of the deceased donor’s aorta, followed by the filling of the heart with a cold oxygenic liquid. This solution, composed of red blood cells, a protective solution, electrolytes and multivitamins, preserves the organ without reactivating it. The heart can then be taken surgically and transplanted under optimal conditions.
The results of the first three adult patients, aged 40 to 60, are remarkable. Six months after their transplantation, all presented a functional heart without a sign of rejection. Encouraged by these successes, surgeons have since extended the procedure to 20 patients with constant positive results.
Towards a new era of transplants
These two techniques represent much more than just technical improvement. They open the way to a significant increase in the number of organs available while respecting ethical considerations that frame medical practice.
Robert Montgomery, specialist in transplantation at New York University, underlines the importance of these advances which bypass the ethical challenges of existing methods. However, as with any medical innovation, these techniques will have to be reproduced on a larger scale to confirm their effectiveness and guarantee the quality of the grafts.
The future of cardiac transplants seems to be clearing up. These new approaches could not only save more lives, but also democratize access to these vital interventions, especially for the most vulnerable patients.
