Normothermic regional perfusion could increase the number of patients receiving lung transplants

Normothermic regional perfusion could increase the number of patients receiving lung transplants

Re-perfusing an organ donor's lungs after the heart has irreversibly stopped beating using a technique called normothermic regional perfusion (TA-NRP) could potentially increase the number of patients receiving lung transplants, researchers said at the annual meeting and scientific sessions of the International Society for Heart and Lung Transplantation (ISHLT) in Prague.

TA-NRP uses a machine to send blood through a donor's abdomen and chest after the heart has irreversibly stopped beating (called donation after circulatory death, or DCD). A 30- to 40-minute supply of blood to these areas revitalizes the heart and ventilates the lungs.

Pedro Catarino, MD, director of aortic surgery at Cedars-Sinai Medical Center in Los Angeles, said techniques like TA-NRP will help provide more available donor lungs to patients on the waiting list. Globally, the overall utilization of available donor lungs is only 20 percent.

The utilization of donor lungs is generally quite poor. We only use one lung for every five organ donors. It's even worse for DCD donors, at just 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 increased to approximately 15 percent with the use of TA-NRP. However, some lung experts fear that in situ perfusion will cause lung damage.

“TA-NRP is technically possible and some surgeons have used it successfully to harvest both the heart and lungs from DCD donors,” said Shaf Keshavjee, MD, MSc, FRCSC, FACS, director of the Toronto Lung Transplant Program. “However, when TA-NRP was introduced in the United States, the frequency of lung removal decreased.

“I think 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 USA and Spain. In Canada, DCD donor lungs are removed from the body and perfused outside the body (ex vivo) in a machine. Machine 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 U.S. only uses four percent.”

Unlike machine perfusion, which is not readily available worldwide, TA-NRP is, according to Dr. Catarino a technique that anyone can use.

“With TA-NRP we are also supposed to measure oxygen transfer in the lungs, which is a very good indicator of the quality of the donor lung,” he said. “The ability to do this functional assessment is one of the big advantages.”

Dr. Catarino said there are data suggesting that outcomes after TA-NRP in DCD lungs are very good.

“TA-NRP is a way to provide more lungs to patients who need them,” he said. “DCD accounted for 32 percent of all organ donors in the U.S. in 2022 and rising.”

The ISHLT created a task force to produce a statement that summarizes the best available evidence and practices for NRP and outlines, among other things, issues, concerns and areas for future research.

Sources: