Donor heart is kept pumping outside of the body until it can be transplanted
For the first time in Illinois, surgeons at Northwestern Medicine Bluhm Cardiovascular Institute successfully transplanted a heart donated after circulatory death (DCD). Until recently, hearts from donors who experience circulatory death were not considered for donation. That is changing thanks to new technology nicknamed “Heart in a Box” that resuscitates a stopped heart, keeping it pumping outside of the body until it can be transplanted into a waiting patient. Estimates suggest that this updated approach could increase the number of available donor hearts for transplant by up to 30 percent in the United States.
Traditionally, heart transplants use hearts from organ donors who have been declared brain dead following a catastrophic event, such a traumatic injury or drug overdose, but their heart remained beating, usually with mechanical assistance. With DCD, the donor experienced similar events with no chance of recovery, but they do not meet the criteria for brain death. Instead, death is declared when their heart and respiratory system shutdown, either naturally or because life sustaining care is discontinued.
When circulatory death is declared, surgeons remove the stopped heart from the donor within minutes then connect it to the TransMedics Organ Care System™ (OCS™) Heart. This portable “Heart in a Box” device reanimates the heart and simulates the environment inside the human body pumping warm, oxygenated blood through the heart while it is transported for transplant. Before this technology, transplant teams would place the donor heart on ice in a cooler to preserve it during transport.
“With standard hypothermic preservation, we only have about four hours to get the heart from the donor to recipient. This time limitation significantly impacts how far we can go to retrieve an organ,” said Benjamin S. Bryner, MD, assistant professor of cardiac surgery at Northwestern University Feinberg School of Medicine, associate director of heart transplantation and mechanical circulatory support and director of the expanded donation program at Bluhm Cardiovascular Institute. “With the OCS™, we’re no longer constrained by time, which means we can travel further across the country. This is particularly valuable for our patients who are harder to match, now giving us more options to find their perfect match and get them the transplant they need.”
In addition to the benefit of time, OCS™ Heart also gives the transplant team greater ability to examine the heart’s condition and assess its functionality. Surgeons can look for signs of injury or damage from coronary artery disease in a way that was not previously possible when the donor died from circulatory death.
“With this technology, we can examine the heart as it beats inside this device during transport, up until it is implanted, giving us a better view and more insight into its functionality, making it possible to perform DCD transplants,” said Duc Thinh Pham, MD, associate professor of cardiac surgery at Northwestern University Feinberg School of Medicine and director of heart transplantation and mechanical circulatory support at Bluhm Cardiovascular Institute. “This gives us even greater confidence in an organ’s viability for transplant and reassurance that it is going to be suitable for our patient.”
While DCD has become increasingly common in transplantation for other organs, including liver, lung and kidney, this practice remains rare for heart transplant. Only a handful on centers in the United States currently perform DCD heart transplant, but centers in the United Kingdom and Australia have successfully used this method for years with encouraging results, including positive patient outcomes, decreased wait times and fewer patients left waiting for a transplant.
In the United States, more than 6 million people live with heart failure and an estimated 10 percent of them may eventually require a transplant or other advanced therapies. Currently, the number of people waiting for transplant far outweighs the number of donor hearts available. In 2021, there were over 7,000 patients on the heart transplant list in the United States. However, only 3,500 heart transplants were performed in the same period due to the scarcity of available donor hearts.
An estimated 70% donor hearts go unused annually, but by leveraging technology and innovative techniques, like DCD transplants, the number of hearts available for transplant could increase by up to 30 percent. For the nearly 3,500 people still waiting for a heart transplant, and the 5,000 more being added to that list each year, this is welcome news.
“The most important element in any transplant is the gift of the heart from the donor and their family,” says Dr. Bryner, who was part of the team that transplanted the first DCD heart in the United States while at Duke University. “I’m thrilled that this gives us more opportunity for those families to have some meaning come from that great loss by sharing their loved one’s heart with the recipient.”
In the more than 50 years since the first heart transplant, the limited supply of donor hearts compared to the demand for transplants has remained the biggest challenge. As the field continues to innovate and seek solutions to the organ shortage, DCD presents a unique opportunity.
“In my 20 years as a transplant surgeon, this is the biggest leap forward our field has taken and the best opportunity we’ve had to expand the number of available hearts,” says Dr. Pham. “At Northwestern, we believe this approach will help us to treat and serve more patients with end-stage heart failure. This is a very exciting opportunity to get more of patients transplanted in less time, so they can get back to their lives and families.”
The OCS™ Heart is the only system used in DCD heart transplantation worldwide and the only FDA approved technology for extracorporeal perfusion and preservation of donor hearts in the United States.
Benjamin S. Bryner, MD, and Duc Thinh Pham, MD, perform the first in Illinois heart transplant using DCD (donation after circulatory death) with the TransMedics Organ Care System (OCS™). “In my 20 years as a transplant surgeon, DCD is the biggest leap forward our field has taken and the best opportunity we’ve had to expand the number of available hearts,” says Dr. Pham.
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