New organ transplant technique utilized
Could reshape entire industry
On some level, the human liver in the operating room at Northwestern Memorial Hospital in Chicago was alive. Blood circulating through its tissues delivered oxygen and removed waste products, and the organ produced bile and proteins that are essential to the body.
But the donor had died a day earlier, and the liver lay inside a boxy plastic device. The organ owed its vitality to this machine, which was preserving it for transplantation into a needy patient.
“It’s a little bit science fiction,” said Dr. Daniel Borja-Cacho, a transplant surgeon at the hospital.
Surgeons are experimenting with organs from genetically modified animals, hinting at a future when they could be a source for transplants. But the field is already undergoing a paradigm shift, driven by technologies in widespread use that allow clinicians to temporarily store organs outside the body.
Perfusion, as it is called, is changing every aspect of the organ transplant process, from the way surgeons operate, to the types of patients who can donate organs, to the outcomes for recipients.
Most significantly, surgical programs that have adopted perfusion are transplanting more organs.
Since 2020, Northwestern has had a 30 percent uptick in its volume of liver transplants. Nationally, the number of lung, liver, and heart transplants each rose by more than 10 percent in 2023, one of the largest yearover-year increases in decades.
Without blood flow, organs rapidly deteriorate. That’s why clinicians have long considered the ideal organ donor to be someone who died under circumstances that ended brain activity but whose heart continued beating, keeping the organs viable until they could be matched with recipients.
To minimize injury to organs after their removal from a donor’s blood supply and before they are connected to a recipient’s, surgeons used to cool them to just above freezing, significantly slowing their metabolic processes.
This extends the window in which organs can be transplanted, but only briefly. Livers remain viable for no longer than 12 hours, and lungs and hearts closer to six.
Scientists have long experimented with techniques for keeping organs in more dynamic conditions, at a warmer temperature and perfused with blood or another oxygenated solution. After years of development, the first device for preserving lungs via perfusion won approval from the Food and Drug Administration in 2019. Devices for perfusing hearts and livers were approved in late 2021.
The devices essentially pump blood or an oxygenated fluid through tubes into the blood vessels of the donated organ. Because cells in a perfused organ continue to function, clinicians can better assess whether the organ will thrive in a recipient’s body.
Bolstered by that information, transplant surgeons have begun to use organs from older or sicker donors that they might otherwise have turned down, said Dr. Kris Croome, a professor of surgery at the Mayo Clinic in Florida. “We’re going after organs we never would have before, and we’re seeing good outcomes,” he said.
Perhaps most important, perfusion has further opened the door to organ donation by comatose patients whose families have withdrawn life support, allowing their hearts to eventually stop. Each year, tens of thousands of people die this way, after the cessation of circulation, but they were rarely donor candidates because the dying process deprived their organs of oxygen.