A team at Duke University Hospital in Durham, North Carolina, used a process known as donation after circulatory death (DCD) to transplant a heart taken from a donor who had experienced cardiac death, the start of a new clinical trial of this approach. The team used the TransMedics Organ Care System (OCS) to perfuse the heart, which had stopped beating, with warm blood after it had been procured. The heart then remained on the OCS until it was transplanted into the recipient — a military veteran with heart failure and ventricular arrhythmias. "DCD differs from the traditional method of heart transplantation, in which the donor has been declared brain dead but the heart has continued beating," Chetan Patel, MD, associate professor of medicine, Duke University School of Medicine and medical director of its Cardiac Transplant Program, told theheart.org | Medscape Cardiology. "This new technology can potentially expand the heart donor pool by about 30%, which would be a really impactful change in our ability to provide this therapy for many more people," he said. David Nelson, MD, a spokesperson for the American Society of Transplantation, told theheart.org | Medscape Cardiology that Australia, the United Kingdom, and Belgium have established DCD transplant programs and there have now been over 100 DCD heart transplants worldwide. The Sydney group reported high 1-year survival rates in adult DCD heart transplants. "The recent adult DCD heart transplant performed at Duke is the first in a five-center US clinical trial is therefore an important further step forward in extending the beneficence of donors and their families to heart recipients," Nelson said. Next Evolution "At least for most of the last few decades, heart transplantation has been done from a brain dead donor whose heart is still beating," Patel explained. "When the surgical team goes to procure the organ, it stops the heart with a preservation solution and transports the heart — usually just on ice — and then replaces the heart into the recipient," he continued. The problem with this approach is that in the process, ischemia can potentially set in, rendering the heart unusable. "There have been some evolutions in technologies that have allowed us to modify the traditional approach with an OCS, using a device that enables the heart to stay warm and beating, so that nutrients from the donor's blood continue to be perfused," he said. The team at Duke has already performed over 40 such transplants and have had a "good experience" with this technology, he reported. DCD however, is the "next evolution" in heart transplantation methods, although it has been used for many years in procuring other organs such as lungs, liver, and kidneys. "Once the family has decided they are at the point when they want to withdraw life support, the donor undergoes a natural death process where blood pressure drops to below 50 for mean arterial pressure, and we know the heart is becoming ischemic," he continued. After asystole, a "stand-off" period of 5 minute elapses, when no procurement can be done to be sure there is no chance of the heart restarting on its own, Patel said. Once the heart has been procured, it is treated with a preservation solution, then placed on an OCS and perfused, restarted, and then assessed to make sure it is viable and healthy enough to be transplanted. After these steps, the heart is transported to the recipient's hospital. When the recipient is ready for the transplant, the heart is removed from the OCS and "transplanted in a standard fashion." Patel said that the recipient of this first DCD procedure is "a gentleman in his 60s with end-stage heart failure that caused significant limitation in daily activities. He also suffered from ventricular arrhythmias." The patient had "gone past the point where any type of conventional therapy for heart failure or electrophysiological procedure could have helped." Since the transplant, "he has been doing well, making a good standard recovery, has walked a few times, and is overall doing quite well," Patel reported. More Acceptable to Families Commenting on the procedure for theheart.org | Medscape Cardiology, Jeffrey Teuteberg, MD, associate professor of medicine and section chief of heart failure, cardiac transplantation, and mechanical circulatory support, Stanford School of Medicine, California, agreed that this new approach has the potential to increase the donor pool. "One of the things we've struggled with in the field of heart transplantation is that there are more people on waiting lists than hearts available, and this technique may help with that," said Teuteberg, who is also a past president of the International Society for Heart and Lung Transplantation. He observed that families of donors are sometimes uncomfortable with the fact that, although their relative has been declared brain dead, the person is taken to the operating room with a heart that is still beating and circulating blood. In DCD, by contrast, the procurement can take place even after the heart has stopped beating, which "may be more acceptable to patients and families and allow more organs to be available." "We often forget in some of these conversations how much of a gift an organ donation is from the donor and the donor's family," Patel commented. "We want to make sure that we always remember that everyone involved [with heart transplantation] are truly grateful for the donation of a gift of life to other individuals," he emphasized. Source
