New methods of preserving organs after circulatory death — or after the heart has stopped pumping blood through the body — are expanding the donor pool for lungs that can be used for transplant.
Michael Cain, MD, assistant professor of cardiothoracic surgery in the University of Colorado Anschutz Department of Surgery, recently led a retrospective study evaluating lung transplant data between December 2019 and March 2025, looking at three-year survival rates for lungs donated after circulatory death compared to lungs donated after brain death, as well as how different methods of preserving organs after death affect survival rates. The paper, published in the journal Surgery, was first-authored by CU Anschutz School of Medicine student Tiffany Maksimuk.
“The first lung transplant from a lung donated after circulatory death was in the early 1990s,” says Cain, who was recently named surgical director of lung transplant in the Division of Cardiothoracic Surgery. “The technique has been around for quite a while, but wider use has not picked up in the percentage of overall transplants until the past few years. Technology has played a role in that.”
For many years, the gold standard for organ donation was donors whose organs were removed after brain death, meaning blood was still circulating in the body. Recent research, however, has shown that organs removed after circulatory death are just as viable when it comes to transplant.
Cain explains that there are multiple ways to preserve organs after circulatory death, including machines that perfuse — or provide artificial blood flow to — organs inside the body, machines that perfuse organs after they are removed from the body, and rapid procurement, in which organs are very quickly removed from a donor and kept in cold storage for immediate transplant.
“One of the points of the paper is that procurement, which used to be fairly straightforward, has now become a field in itself, with multiple different techniques that can be used. Our role as transplant surgeons is to understand when to use them and how to use them to support the best outcomes for each patient,” Cain says.
The most important finding from the study, Cain says, is that three-year survival rates were comparable between organs procured after circulatory death and those procured after brain death. He and his fellow researchers also found no significant differences in survival rates based on procurement method. He hopes this data means donation after circulatory death continues to become more widespread.
“Donation after circulatory death is increasing in frequency, and it's increasing in the proportion of lung transplants nationally,” he says. “That could mean that people are getting more comfortable with the idea of donation after circulatory death, but there's also an increased interest in aggressively pursuing donors to provide access to people who are waiting for lungs. We want to give every chance possible to help a lung transplant candidate receive an organ.”
The study also notes that as the technology for perfusing organs outside of the body (“ex vivo”) continues to improve, it offers additional opportunities to improve the organs for transplant. Ex vivo perfusion allows surgeons to evaluate lung function before putting the organs into a recipient, and in some cases treat diseased lungs to make them more suitable for transplant.
“There's a lot of hope and interest in being able to take lungs that have a little bit of pneumonia, which is common, and be able to treat that pneumonia over a period of time and watch it get better and then implant the lungs into somebody,” Cain says. “Some of these machine perfusion technologies show promise that could mean a better future for certain lungs.”
Cain notes that the techniques and technologies detailed in the study are available to patients at the CU Anschutz Department of Surgery, and that CU surgeons are looking for every advantage when treating patients who need a lung transplant.
“People who are listed for transplant are very sick, so if you can get them transplanted, that's a good thing,” he says. “We're looking to be creative and aggressive about using technology to help our patients.”