Duke University researchers compared the effectiveness of heart transplants taken from donors who underwent circulatory death versus those who underwent brain death and found the transplant methods comparable.
Donation after circulatory death (DCD) organ transplants account for about one-fourth of after-death organ transplants in the United States.
The researchers suggest that increasing reliance on this method could improve the heart transplant donor pool by 30%.
Surgeons at Duke University pioneered heart donations through a process known as Donation after Circulatory Death (DCD) in 2019. Today, they present new research to validate the safety and effectiveness of the DCD method, suggesting that DCD heart transplantation is just as effective a method as traditional heart transplantation.
The research involves a randomized, noninferiority trial of 180 patients who underwent heart transplantation, 90 of whom received a heart after circulatory death of their donor and 90 of whom received a heart after brain death of their donor. Participants were assigned to a certain type of donor but only given their assignment if it was available first. In the group studied, the risk-adjusted 6-month survival was 94% among recipients of a DCD heart and 90% among recipients of a heart from a brain-death donor.
The researchers concluded that DCD heart transplants were “not inferior” to transplants from brain-death donors, the more common standard of care. They added that reliance on this method could increase both the donor pool for heart transplants and access to care.
“This should eliminate any barriers for transplant centers to offer this to their patients because we now have objective, randomized data showing both types of hearts are equivalent,” said corresponding author Jacob Schroder, MD, in a press release. Schroder performed the first DCD heart transplant at Duke University Hospital in 2019.
A gap in DCD donation numbers and transplant use
Increased use of this method is expected to increase the organ donor pool by 30%. For transplant numbers to increase, however, more centers will need to utilize these donations.
Since the DCD heart transplant method was successfully introduced in 2019, DCD heart donations have been “rapidly” increasing in the United States, according to the study. But the increase in available organs hasn’t quickly translated into an increase in DCD transplants. In 2020, DCD donations accounted for only 25% of all organ donations after death.
The new trial offers a roadmap for other centers to adopt DCD transplant methods and increase these numbers, says Adam DeVore, MD, MHS, study author and Associate Professor of Medicine in Duke University’s Department of Medicine, Division of Cardiology.
Since 2019, the method “has allowed us to offer transplants to more patients in need, but also earlier in their disease course, before they become so sick they have difficulty recovering from the surgery,” DeVore adds. “Our goal is to offer transplant to patients at the right time— where they can undergo surgery and recover and still thrive soon after.”
A comparison of DCD and DCD transplants
Traditionally, surgeons conducting heart transplants use hearts from donors who have undergone brain death, which is most commonly what people understand as death. Brain death involves the death of all brain activity.
In 2019, Duke surgeons led the first DCD heart transplant from donors who had undergone circulatory death. Circulatory death involves the death of all circulatory and respiratory functions. While this is irreversible, some brain reflexes remain.
According to Ronald Grifka, MD, cardiologist and Chief Medical Officer at the University of Michigan Health-West, DCD transplant donors are “declared dead based on no heart rate or blood pressure. Then the heart is harvested for transplant.”
“Due to the severe shortage of hearts for donation, recently there has been interest in using a technique of obtaining hearts for transplant after the patient has had a declaration of circulatory death,” says Grifka.
How does a DCD transplant work?
When transplanting a heart from a brain-death donor, time allows for freezing of the organ and an in situ assessment of cardiac function before the operation. When transplanting a heart from a circulatory death donor, this method does not apply.
Rather than freeze the organ, doctors at Duke used a machine to “keep the heart pumping, making it viable for donation, but also enabling the organ to travel further,” according to the press release.
In the study, hearts that could be transplanted using the DCD method needed to meet certain criteria in order to be viable, including:
“[S]table or downward-trending circulating lactate levels after adequate
perfusion was established;
[S]table perfusion levels;
and clinical acceptance of the donor heart for transplantation by the transplanting surgeon or cardiologist.”
Before surgery, DCD hearts were also “flushed with cold crystalloid del Nido cardioplegia solution” and “surgically retrieved and placed on the perfusion system.”
DCD transplants are more commonly used for organs other than the heart. Pediatric DCD heart transplants were introduced later, in August 2021.
DCD transplant risks
No transplant surgery is risk-free, and DCD heart transplantation is no exception.
According to Grifka, heart transplants after DCD may present technical and ethical challenges, including the tasks of “‘restarting’ the heart after circulatory death has been confirmed” and “preserving the heart while it is transported to the donor patient,” as well as the ethical discussion of when to declare that a person has undergone circulatory death.
Risks were also acknowledged in the trial, which revealed that within the first 30 days after transplantation, the “mean number of serious adverse events associated with the heart graft” was higher among DCD heart transplant recipients than brain-death organ recipients. Further, compared to people who have received transplants from a brain-death donor, DCD recipients may also experience “more delay before normal graft function occurs, meaning the hearts can be slow to wake up after transplant for hours to a day or two,” says DeVore. “Despite this, patients still do as well as those receiving transplantation through traditional means with a donor declared brain dead,” he adds.
Researchers also noted that the detected risks did not impact the survival rate.
“Trying innovations in heart transplantation is a real challenge,” says DeVore. “The stakes are high, and there are a lot of disincentives to trying to do high-quality research like a randomized clinical trial in this field. The investigators, patients, families, and study teams should all be commended for the courage and effort required to complete a study like the DCD Heart Trial.”
More research, longer patient follow-ups, and a broader assessment of DCD transplants could help fine-tune the procedure, but doesn’t downplay its importance, says Grifka.
“With the impressive shortage of donor hearts available for transplant, DCD and possibly other techniques provide an interesting opportunity for future development,” says Grifka.
What this means for you
Four years after pioneering DCD heart transplantation, Duke University researchers are releasing a new study on the safety and effectiveness of the method. They say that DCD heart transplants are not inferior to transplants from brain-death donors and that increasing the use of this method could have a profound impact on patients in need of heart transplants.