Kenneth McCurry, MD, surgical director of the lung and heart-lung transplant programs and cardiothoracic surgeon at the Cleveland Clinic, talks about a new method for expanding the amount of usable lungs for organ donation.
Now, I was surprised learning about this story. How many lungs are donated that go unused?
Dr. McCurry: Yeah, it’s really unfortunate. So, lung transplantation has grown a great deal since it was first started, really in the 1980s or so. In the first few years, there weren’t many done at all and over the last 30 years, we’ve gone from doing about seven to eight hundred a year to doing about 25 hundred lung transplants a year. But still, for every two to three patients that we transplant in the United States, there’s one patient that dies on the waiting list. As you allude to, it’s extremely unfortunate that still, even today, of all the donors in the United States that donate an organ– so a kidney liver whatever else it may be, we use lungs from only about 20 percent. So, two out of 10. 80 percent of lungs are still going wasted despite that waiting list mortality.
Why would they go wasted?
Dr. McCurry: There are common reasons why the lungs don’t work well. It’s easy to evaluate a heart, for a heart surgeon. It’s easy to evaluate a heart and you can do an echo. It’s easy to evaluate a liver. The lungs, however, are just a little fickler. They’re a very difficult organ. There are lots of things that can make them not look good. So, a little extra fluid, a little extra saltwater from being in the hospital prior to the patient’s death, a little infection, or perhaps just areas of a lung not being completely expanded, what we call atelectasis. All those things can make the lungs look unusable. But a lot of people now think that, with some treatment, those things can be made better and potentially utilized to help more people and to save more lives.
And that’s the ex vivo?
Dr. McCurry: Yes, that’s where the ex vivo comes in. So, the idea behind the ex vivo lung perfusion is to take marginal lung, so, lungs that aren’t working well or where there are logistical reasons why we can’t immediately take them to transplant. To take them out of the donor, flush them like we normally would, and then ultimately, put them on a machine. When the machine perfuses fluid through the lungs, the fluid is a special kind of fluid that has what we call a very high oncotic pressure, which simply means that it tends to draw fluid into the existing fluid. So, it would draw fluid out of the lungs into the vasculature. So, if the lungs are wet, we can use that system to draw the fluid out. We can do other things on the machine. But basically, the machine has a pump, an oxygenator, a warmer, a few other sorts of technical things. Same sort of machine that we use in the operating room every day and we perfuse the lungs on that machine for a period of time and try to make them better. And, if they get better we can assess them and then ultimately transplant them.
Now, have you been surprised when you’ve seen lungs and say “Oh, we can’t use those” and then they go into the machine and they’re actually usable?
Dr. McCurry: Yeah, and we first started doing this years ago, here in my laboratory initially, experimentally, about eight, nine years ago. And then clinically, we’ve been doing it now for two or three years, so lungs that we actually physically transplant to patients. When we first started we were quite amazed that there were some lungs that we perfused that we didn’t think would be usable. But they got much better on the machine and performed quite well then we ended up transplanting them to the patient.
Can you say how many lungs a year you’re able to use that you wouldn’t have been able to use?
Dr. McCurry: What we’ve done in the last year and a half or so is about 45, now extra, transplants that we otherwise wouldn’t have been able to do. So, 45 transplants off of the machine. So that’s 45 patients that otherwise may have not have gotten a lung or a set of lungs and may have died waiting for a set of lungs.
Now, are there any more risks to taking the lungs out, doing this, then transplanting them? Are there more risks to the patient receiving them?
Dr. McCurry: We don’t think so. So, obviously, it requires some judgment and some experience. We’ve learned that there are certain lungs that the likelihood of being able to convert them to transplantable lungs is extremely low. It requires judgment once the lungs are on the device to determine whether they’re transplantable or not. So, experience matters, and we’ve gained a lot of experience over the last couple of years. But when we accept lungs within the parameters that we think look acceptable, patients have done just as well after a transplant with these sorts of lungs compared to lungs that are taken directly to transplant.
Do you think this will open up the door to people who might be too far along to be considered for a transplant?
Dr. McCurry: Well that’s part of our hope. The statistics are, one patient dies for every two to three that we transplant, now, in the United States, based on our current listing criteria. So, we decide whether to list the patient now or not based on lots of different criteria and there are certainly national and international guidelines. But I think that those guidelines are a bit restrictive and they’re a bit restrictive because it’s a very limited resource. We don’t have enough to go around right now. If we had enough lungs where we could simply take them off the shelf or had a room full of these machines sort of perfusing lungs that we could ultimately transplant, then I think we could expand the recipient pool. Well-meaning offering, as you suggest, to patients that we currently wouldn’t list for a lung transplant.
Is it all done in the operating room at the same time as when it normally would and how much longer does it take?
Dr. McCurry: Yes. So, there are a couple of different techniques. The technique that we use, and that we think it works quite well, is sort of a stationary technique meaning, that it’s a stationary device that we don’t take with us. We go get the lungs, we bring them back here or we take them to a centralized EVLP facility. There is also a business model that a company is working on in this regard. But then we bring them back here and in the device that we have, not in the same operating room as the recipient, but it’s basically old operating room space. It’s sterile space, positive pressure ventilation, all the things that we would typically have when we’re doing an operation or exposing organs. So, that’s a dedicated space that we’ve developed here at the Cleveland Clinic. We not only perfuse lungs there, but the liver team perfuses livers the kidney team perfuses kidneys there, and we have goals of doing intestines and other organs as well all with the goal of trying to make them better. So, that’s a dedicated space that the clinic has built out for us to do this and then if the lungs are acceptable, we package them up and physically take them to the operating room where we’re doing the transplant.
How long does that take to see if they’re acceptable?
Dr. McCurry: So, they’re on the machine generally anywhere from three hours to up to about six hours right now. We’re working on some techniques and approaches where we can actually extend that out to longer periods of time as well.
So, this same type of machine is working on a bunch of different organs already?
Dr. McCurry: Yeah, it’s a little bit different. So, our liver group here actually developed their own machine that uses a little bit different solution, and that machine is portable. They’re currently doing a clinical trial looking at using that as preservation, meaning livers that they would otherwise transplant, they’re comparing transplanting those livers the standard way versus perfusing them with the machine. Then they hope to begin, very soon, to extend into this sort of marginal organ criteria and there’s some experimental work being done here with intestines as well.
You can kind of compare this to walking out the organ and seeing if you can get all the crud off and everything?
Dr. McCurry: Sure, exactly. So, to not get too technical, but at least when someone dies and they’re what we call brain dead, which means that the brain has died and the other organs are still working, that’s the majority of donors that we get lungs from. In that process, there are lots of things that happen to the body, lots of hormones and molecules that are excreted into the blood system, and a lot of those are very bad for the organs. So, part of the benefit of taking the organs out of that environment and putting them on a machine is simply getting them out of where all those bad humors, if you will, are sort of circulating and causing damage to the organs. So, that’s part of the benefit and then we perfuse these sorts of special solutions that can do lots of good things as well. I’ll also add that we and lots of other people around the world really sort of see this as a platform that we can begin to use to make improvements in the organ. So, not only to improve the function but if we can put the organs on the device and keep it on it for a few hours then we might be able to deliver new genes to the organ that makes it less immunogenetic, meaning that it would lower the chance of the recipient rejecting the lung. It might be possible to treat the lungs with different medications that might improve both the short and the long-term outcome. So, we really see it as a platform for sort of engineering good organs based on the recipients who might get those particular organs and hopefully, improve life expectancy for the organs as well.
Now Dan Lynch says that he probably would not be here today if it wasn’t for the ex vivo.
Dr. McCurry: That’s true. He was very sick by the time he came to a transplant and we were having a difficult time finding organs for him for a variety of reasons, his blood type, a few other things like that. So, he was one of the first patients that received organs off the EVLP machine at our center and he did quite well. I think he’s enjoying a great life now.
Anything else I’m missing?
Dr. McCurry: No, I would just emphasize the benefits of donation and for everyone considering being an organ donor. Part of the way of solving the organ crisis and an inadequate number of organs is for everybody to be sure to talk to their family and to designate on their driver’s license that they want to be an organ donor.
Interview conducted by Ivanhoe Broadcast News.
END OF INTERVIEW
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