U surgeons breathe new life into the practice of lung transplantation— with implications for heart transplants, too
At the University of Minnesota Medical Center today, the lung transplant waiting list is half the length it was six months ago, thanks in part to a new technology that’s making more donated lungs worthy of transplantation.
“For some patients, that is the difference between life and death,” says U assistant professor of surgery and cardiothoracic surgeon Gabriel Loor, M.D.
The TransMedics Organ Care System is a device that keeps donated lungs warm and breathing during transportation instead of the standard practice of putting them on ice. The machine pumps blood and oxygen through the donated lungs to simulate what they’d be doing in a living human body. In a sense, the lungs are virtually alive until they reach their recipient.
The device also may be able to rescue marginal lungs, meaning that doctors might be able to improve lungs that otherwise would have been turned away for being notquite- perfect enough to be transplanted. It gives the lungs time to be nursed in a sterile and protective environment and monitors their progress until they meet or exceed standard donor organ criteria.
TransMedics has a similar machine that’s used to transport donated hearts for transplantation, and today a University team is gearing up to explore in the lab the technology’s potential for improving the quality of donor hearts as well.
It’s an important quest. Today about 80 percent of heart and lung donor organs aren’t used in a transplant because there’s no standard method to monitor them and make sure they’re good enough, Loor says. But the TransMedics Organ Care System helps surgeons evaluate the quality of those organs and may even be able to improve some that previously would have been considered marginal.
“It’s revolutionizing the way that we look at transplants,” Loor says of the technology. “Instead of bringing it over on ice, we’re keeping the organ in its own native state. It’s like bringing it over in a miniaturized ICU—transporting it from point A to point B without any downtime.”
Taking the next step
TransMedics is developing different versions of the technology to use for liver and kidney transplants, as well. Its technology for hearts is already in use at some transplant centers, and one clinical trial deemed it just as good as transporting the organ on ice. The amount of time the hearts spent on the device far exceeded the time they’d normally spend on ice but showed equal outcomes, Loor says.
At the University, Loor and colleagues Paul Iaizzo, Ph.D., Angela Panoskaltsis-Mortari, Ph.D., Demetri Yannopoulos, M.D., and others are taking what they already know about hearts a step further.
With a generous grant from biotech company United Therapeutics, the University researchers purchased another TransMedics Organ Care System for lungs to be used only for laboratory investigations. They expect to purchase another machine for heart research, too, and answer a few important questions: When an organ is hooked up to the device, can the amount of time that a donated heart or lung is out of the body be extended beyond the four- to five-hour maximum now considered safe? Can the device help improve the quality of those organs? Can an infusion of a protective agent provide more stability to the organs? Could the technology even allow diseased hearts or hearts that failed time to regenerate if stem cells are introduced?
“It’s been an amazing collaboration that would only be possible at a place like this,” Loor says.
In November, a team of University surgeons performed the first “breathing lung” transplant in the Midwest using the TransMedics Organ Care System. The recipient, a 51-year-old Minnesota man who had suffered from emphysema, left the hospital at a “record pace” and is still doing well today, Loor says.
The TransMedics Organ Care System for lungs is young; the first ever recipient of “breathing lungs” is less than a year out from the transplant. So its true long-term benefit is yet to be discovered. But Loor is encouraged by what he has seen so far.
“Preliminary results suggest that the amount of what they call primary graft dysfunction, how much injury the lung sustains, is significantly reduced—50 percent reduced—if the lungs are procured with the device versus ice,” he says. “That’s probably going to turn out to be a big deal. We already know that the amount of lung injury in the first one to three days [posttransplant] predicts how patients are going to do in the long term. Anything we can do now to make [the process] better is worth it.”