The relatively recent innovation of heart transplantation after circulatory death of the donor is increasing the number of donor hearts available and leading to many more lives on the heart transplant waiting list being saved. Experts agree it’s a major and very welcome advance in medicine.
However, some of the processes involved in one approach to donation after circulatory death has raised ethical concerns and questions about whether they violate the “dead donor rule” – a principle that requires patients be declared dead before removal of life-sustaining organs for transplant.
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Experts in the fields of transplantation and medical ethics have yet to reach consensus, causing problems for the transplant community, who worry that this could cause a loss of confidence in the entire transplant process.
A new pathway for heart transplantation
The traditional approach to transplantation is to retrieve organs from a donor who has been declared brain dead, known as “donation after brain death (DBD).” These patients have usually suffered a catastrophic brain injury but survived to get to intensive care.
As the brain swells because of injury, it becomes evident that all brain function is lost, and the patient is declared brain dead. However, breathing is maintained by the ventilator and the heart is still beating. Because the organs are being oxygenated, there is no immediate rush to retrieve the organs and the heart can be evaluated for its suitability for transplant in a calm and methodical way before it is removed.
However, there is a massive shortage of organs, especially hearts, partially because of the limited number of donors who are declared brain dead in that setting.
In recent years, another pathway for organ transplantation has become available: “donation after circulatory death (DCD).” These patients also have suffered a catastrophic brain injury considered to be nonsurvivable, but unlike the DBD situation, the brain still has some function, so the patient does not meet the criteria for brain death.
Still, because the patient is considered to have no chance of a meaningful recovery, the family often recognizes the futility of treatment and agrees to the withdrawal of life support. When this happens, the heart normally stops beating after a period of time. There is then a “stand-off time” – normally 5 minutes – after which death is declared and the organs can be removed.
The difficulty with this approach, however, is that because the heart has been stopped, it has been deprived of oxygen, potentially causing injury. While DCD has been practiced for several years to retrieve organs such as the kidney, liver, lungs, and pancreas, the heart is more difficult as it is more susceptible to oxygen deprivation. And for the heart to be assessed for transplant suitability, it should ideally be beating, so it has to be reperfused and restarted quickly after death has been declared.
For many years it was thought the oxygen deprivation that occurs after circulatory death would be too much to provide a functional organ. But researchers in the United Kingdom and Australia developed techniques to overcome this problem, and early DCD heart transplants took place in 2014 in Australia, and in 2015 in the United Kingdom.
Heart transplantation after circulatory death has now become a routine part of the transplant program in many countries, including the United States, Spain, Belgium, the Netherlands, and Austria.
In the United States, 348 DCD heart transplants were performed in 2022, with numbers expected to reach 700 to 800 this year as more centers come online.
It is expected that most countries with heart transplant programs will follow suit and the number of donor hearts will increase by up to 30% worldwide because of DCD.
Currently, there are about 8,000 heart transplants worldwide each year and with DCD this could rise to about 10,000, potentially an extra 2,000 lives saved each year, experts estimate.
Two different approaches to DCD heart transplantation have been developed.