Re-infusing an organ donor’s lungs after the heart has irreversibly stopped beating with a technique called normothermic regional perfusion (TA-NRP) could potentially increase the number of patients receiving lung transplants, according to researchers at the Annual Meeting and Scientific Sessions of the International Society of Heart and Lung Transplantation (ISHLT) in Prague.
TA-NRP uses a machine to pass blood from a donor’s abdomen and chest after the heart has irreversibly stopped beating (called donation after circulatory death, or DCD). Thirty to forty minutes of blood infusion into these areas invigorates the heart and aerates the lungs.
Pedro Catarino, MD, director of Aortic Surgery at Cedars-Sinai Medical Center in Los Angeles, said techniques like TA-NRP will help get more of the available donor lungs to patients on the waiting list. Globally, the overall utilization of available donor lungs is only 20 percent.
Donor lung utilization is generally quite poor. For every five organ donors, we only use one set of lungs. It’s even worse for DCD donors, only four to six percent in the US. The vast majority of DCD donors do not donate their lungs.”
Pedro Catarino, MD, Director of Aortic Surgery at Cedars-Sinai Medical Center
Dr. Catarino presented data showing that the recovery rate for DCD lungs has increased to about 15 percent with the use of TA-NRP. However, some lung specialists are concerned that the lungs are injured during the in situ perfusion process.
“TA-NRP is technically possible, and some surgeons have used it successfully to recover both heart and lung from DCD donors,” said Shaf Keshavjee, MD, MSc, FRCSC, FACS, director of the Lung Transplant Program at Toronto. “However, when TA-NRP was introduced in the US, the frequency of recovery from the lungs decreased.
“I believe NRP could save more hearts, kidneys, livers and lungs,” said Dr. Keshavjee. “But we need to standardize our technique because there are too many examples of good donor lungs damaged by TA-NRP.”
TA-NRP is currently only used in the US and Spain. In Canada, DCD donor lungs are removed from the body and perfused outside the body (ex vivo) in a machine. Mechanical perfusion, which gives the surgical team control over the fluids used to perfuse the lungs, has been extremely successful for the Toronto Lung Transplant Program.
“We have the largest lung transplant program in the world,” said Dr. Keshavjee. “We use 40 percent of DCD lungs, while the US only uses 4 percent.”
Unlike mechanical diffusion, which is not readily available worldwide, Dr. Catarino said TA-NRP is a technique anyone can use.
“Using TA-NRP, we also measure oxygen transport in the lungs, which is a very good indicator of the quality of the donor’s lungs,” he said. “Being able to perform this functional assessment is one of its great benefits.”
Dr. Catarino said there is data to suggest that outcomes after TA-NRP for DCD lungs are very good.
“TA-NRP is a way to offer more lungs to patients who need them,” he said. “DCD was 32 percent of total US organ donors in 2022 and the trajectory is upward.”
ISHLT has initiated a working group to produce a statement summarizing the best available evidence and practice on NRP, including outlining issues, concerns and areas for future research.
