ATS Breathe Easy - How Lung Transplant Mortality Dropped After CAS Implementation

The lung Composite Allocation Score (CAS) was implemented in 2023, and has shown to increase lung transplant rates and lower waitlist mortality. Host Alice Gallo de Moraes, MD, of the Mayo Clinic, interviews experts Mary Raddawi, MD, of Columbia University Irving Medical Center, and Amy Skiba, of the Lung Transplant Foundation, on the importance of CAS and how it has changed outcomes for lung transplant patients. 

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[00:00:00] non: You are listening to the ATS Breathe Easy podcast brought to you by the American Thoracic Society.
[00:00:18] Alice: Hi everybody. Welcome to ATS Breathe Easy podcast. I am Alice Gall intensivist at Mayo Clinic in Rochester, Minnesota, and I have the privilege of talking today with Dr. Mary Rod and Amy Skiba. Dr. Rodi completed her residency training in internal medicine and Mass General Hospital. She's now a third year pulmonary critical care fellow at Columbia University Irving Medical Center at ATS last spring, she presented research on how the new composite allocation scoring system has improved wait list outcomes, especially among the most critical I lung transplant candidates.
Amy. Is [00:01:00] the executive director of the Lung Transplant Foundation, a national non-pro nonprofit dedicated to improving outcomes and quality of life for lung transplant recipients and their families. In her role, Amy leads advocacy initiatives. Patient education programs and groundbreaking peer support services, including the Joseph J.
Carter Mentorship program, the only nationwide program of its guide. She has spearheaded large scale awareness efforts such as BOS Education Day and the inaugural Lung Transplant Awareness Day, bringing together patients, caregivers, clinicians, industry, and policy policy makers to elevate transplant care and research.
With a strong focus on collaboration, Amy works closely with academic centers, industry partners, advocacy organizations, and medical societies to accelerate access to new and emerging therapies, clinical trials and patient centered resources. Her work reflects a deep commitment to [00:02:00] ensuring every patient and caregiver has the knowledge, support, and community needed to navigate the challenges and enjoy the hope that lung transplantation brings.
I'm so excited to talk to both of you today. Welcome. Thank you. It's nice to be
[00:02:13] Mary: here.
[00:02:14] Alice: Thank you so much. I am going to start with my first question to Dr. Rodi. For those who may not be familiar, what is the continuous allocation score, CAS, and why was it developed?
[00:02:30] Mary: Sure. So, the composite allocation score is basically the latest, version of the lung allocation system.
It was implemented in 2023. The reason that it was implemented is that in the older systems before the cas, donor lungs, whenever they became available, they were. distributed within a very strict, [00:03:00] geo Geographic boundary called a donation service area. So there was 58 donation service areas and essentially lungs were only allocated within their very specific donation service area.
And we saw that in those. Older systems that relied so heavily on very strict geographic boundaries. Mm-hmm. We're actually seeing differences in wait list outcomes based on where you happened to live. And so the cas, is a huge change in the way that lungs are allocated because, there are many different components that go into the cast outside of geography, you know.
Important components that end up overtaking, geography.
[00:03:49] Alice: Yeah.
[00:03:51] Amy: Amy, anything to add to that? Yeah, I think the really exciting thing is, you know, this sort of went hand in hand with so many new and [00:04:00] emerging technologies that were also coming into lung transplant to make this possible. So, you know, there's new technology with transportation and.
transportation of organs. You know, it's one of those things where it's like, gosh, how does that really happen? And seeing it go from, you know, small little coolers on airplanes to the amazing technologies that we're seeing now where we can track these organs and get real time. you know, feedback from them so the patient has the best possible outcome is just amazing.
So, you know, the score and having these new technologies brings those together, you know, just to allow so much more access to organs than we had before.
[00:04:39] Alice: I love that. And Amy, if you could tell us how this. Cast differs from the previous system, the the lung allocation system, and specifically what were the factors that were included in the continuous allocation score that, are now weighted a little [00:05:00] heavier in order to allocate the organs.
And I was also hoping that you could, tell us more about like the difference between distance to transplant center and how like. This gets the lungs get or allocated.
[00:05:16] Amy: Sure. So I think we could probably tag team this a little bit and get into some, some specifics. But I think overall, from a patient perspective, the biggest thing we saw was the geography that we're talking about.
So that used to be the, the biggest factor almost in, in the score. And it, it sort of has changed and now. You know your outcomes and certain, certain things are scored differently. So if you are a pediatric patient, you are scored differently. if you have some things we talked about, accessibility, that might make your transplant more difficult.
So there are some blood types that make transplant more difficult. your stature. So if you are someone that is small in height, that is also something that is harder [00:06:00] to transplant. So. These scores, take those factors, those personal things, that didn't account for as much before and really looks at that person and says, you know, how can we look at this person holistically, not just in relation to where they reside to their transplant center to make sure they're having the best outcome.
So outcomes being weighed more heavily is something that we really like to see on the patient side.
[00:06:24] Mary: Yeah, totally. And I, I can add too, just to kind of go through, like the specific factors that are in the, CAS system. So, in the CAS, you know, you know, like Amy mentioned, it's the biggest pieces of the pie that go into the score are medical urgency.
Mm-hmm. five year post-transplant survival. Oh. The third very important group, which was not a part of the LAS scoring, like Amy mentioned, is this piece of the pie, [00:07:00] of biological factors. So, like Amy said, you know, short stature, you're gonna get. Extra points, because those patients are facing a more limited candidate pool, your sensit sensitization.
So, we measure that basically by like CPRA levels. Um mm-hmm. And then finally blood type, like Amy mentioned, you know, if you have typo blood, again, you're facing a more limited donor pool, so you get extra points if you're someone who. Unfortunately faces a more limited donor pool based on those biological differences.
So that's that third piece of the pie. the fourth piece is, patient access. So again, pediatric patients get additional points there. And then the fifth piece is geography, so placement, efficiency, but that piece of the pie and the actual cast score is pretty small and it's so small that. You know it, it will never overtake [00:08:00] your points based on that you're getting based on how sick you are.
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[00:08:38] Alice: So Dr. Avi at ATS 2025, you presented an abstract or mortality in critically ill patients since the implementation of, of, the continuous allocation score. Share with our listeners what were the main findings of our, of your study.
[00:08:54] Mary: Sure. So, what we looked at is differences in wait list [00:09:00] outcomes, basically across the different eras of allocation systems. So pre 2017, we were still allocating lungs based on those very strict geographic borders, the donation service areas. Post 2017, there was actually a change in which the geographic borders became slightly, you know, less rigid.
So lungs were allocated, in a 250 nautical mile radius. And then post 2023, we have the implementation of the CAS system in which geography really just plays, a minor role. So in our research we wanted to see, you know, how have. These changes in the allocation system throughout the years affected weightless mortality.
And one thing we wanted to look at specifically is how has it affected actually the sickest patients on the list? And so just to give some, just general numbers, so. [00:10:00] We looked at the top 5% of patients in terms of medical urgency, so really, you know, the sickest patients waiting for lungs. We found that in the, you know, in the pre 2017 era wait list, mortality was around 34.5% in the post 2017 era.
Wait list mortality was around 22.2%. Wow. and then in the post cast era, so post 2023, the wait list mortality was around 6.5%. That's all for patients in the top 5% with regard to medical urgency. So what we saw, and as you can see from those numbers, is that. Weightless mortality really has continued to improve as we've made these changes to the allocation system.
and the change that we've seen has been most dramatic for the patients. who are the sickest, the, the, the most critically ill on the waiting list, which I think is reflective of the fact that these [00:11:00] changes are, are, are positive and helpful for patients.
[00:11:03] Alice: That's fantastic. Yeah.
[00:11:05] Amy: I think what's really exciting too is just to, you know, to, to talk a little bit more about the data.
Yeah. The data hasn't always been readily available to patients, so data is something that, you know, in the medical world, it's. It's just so common. It's the everyday, it's the everyday life and what we do every day, to the average patient living in, in data is not something that they're used to. Mm-hmm.
So, within the last few years, we have a lot of acronyms in our world, so I always say that, a lot of people don't really understand the transplant system in its totality because it is. It is massive. And you know, organizations like OPTN, the Organ Procurement Transplant Network, they have partnered with SRTR, which is the Scientific Registry of Transplant recipients.
So there is data in an entire dashboard [00:12:00] available to patients. Now they can compare centers, they can per, they can compare. Survival rates, wait time lists. They can see five-year outcome data. So SRTR is working directly with OPTN, so it is the exact information that transplant centers are are giving back to OPTN and using that data to.
To say to patients, we're gonna, we made a very pretty dashboard on this website that you can easily, you know, put in some qualifying factors, including, you know, geography and, and some of those other things that are a major factor that come into play when someone's looking at a transplant and you can see what your viable options are.
it's also a great way to actually see where all of your options are for a transplant in the United States. So, it's really the first opportunity patients have had to see. All of the information they need in one place. So it's, it's exciting to see the data come back in and [00:13:00] help patients in a real way to see it.
That's
[00:13:02] Alice: amazing.
[00:13:03] Amy: It's, yeah.
[00:13:04] Alice: Amazing. I love that. And Amy, if you could tell us. What does it mean, like all, all of this, what does it all mean for the patients that are currently in the transplant list?
[00:13:16] Amy: So, I mean, currently we actually don't hear a ton about this score anymore. Now I will say. When it first came out, it, there was a lot of, you know, hesitation questions.
What is gonna change? How is my score gonna change? Is it gonna change overnight? And, and is my, is my entire transplant gonna be at risk? you know, there was a lot of fear, but none of that happened. and I think we did a really great job of educating patients for them to understand what the score was, and, you know, worked with OPTN, we worked with transplant centers, we worked with, you know, anyone we could to really get the message out about what the changes were going to be and how you could have a [00:14:00] conversation with your doctor about the things that you might be nervous about.
I think overall though, the changes were. Overwhelmingly in favor of the patient. And that was very, very obvious. I think geography has has and was always a major point of contention for patients. and it also made things very difficult to know there was a viable organ that just wasn't available to you even though you were the right fit.
[00:14:24] Alice: Mm-hmm. Yeah. Dr. Does, the continuous allocation score address some of the inequities patients have experienced in the past?
[00:14:36] Mary: Yeah, I think kind of just like Amy said, I think what's so important about this is that, you know, we can tell patients now that you're not going to be facing wait list disparities just based on where you happen to live, where you happen to get sick.
Yeah. the other piece of this too is that. You know, because in this new scoring system we're giving, you know, some [00:15:00] points, you know, for certain biological disadvantages like your height, your blood type. you know, we're also attempting to address some of those disadvantages just faced by patients based on, you know, just these kind of random biological factors.
[00:15:20] Amy: I think the great thing too has been the response from OPTN and, and the community as a whole. we really push open public comment periods. that's something I think patients don't really know enough about, is you have the ability to say exactly what you think in these situations that affect your health, and we really push patients to submit.
Their testimony of what may have happened to them that is driving their decision to reach out and, and give their feedback. But you know, we always say to patients, you know, everything we do, we don't have jobs. If it wasn't for you, you know, we would do what we do if it wasn't for you. So, [00:16:00] you know, everything we design and create that is.
Is better for you is ultimately what's going to, to, to keep us all, you know, doing what we're doing and keeping them healthy. So, you know, the feedback is so important and I mean, just in the short amount of time, that the continuous multiplication score has been here, we've already seen, I think we're at four different potential public comments where they have seen, Hey, this new score is showing.
we had issues, I don't wanna say issues, but, there was a concern with, type O blood, right? Dr. Aldi, where there was, you know, they realized there was a disparity very, very quickly. And within a year we were able to see them say, you know, we're raising a red flag because we see this happening in the data.
And very quickly they were able to get it into public comment and, and get feedback and make a change
[00:16:51] Alice: starting with Dr. Both of you to say one pearl of wisdom that you wish the [00:17:00] large ATS community would know, should know. To help our patients in like the lung transplant list more about the system or about the new allocation, or about some of the things that Amy said that are readily available.
So Dr. Avi, let's start with you.
[00:17:17] Mary: Sure. I think Amy kind of touched on this, but I think that. What's really cool about seeing how the allocation system has progressed over time is, you know, a lot of it has been based on data, but a lot of it had, al has also come from patient advocacy. and so I think just.
This is something that we can tell patients like, you know, your advocacy actually can have a real impact in the way that we think about these systems and the way that we allocate lungs. You know, like the initial change between, using the donation service areas. And extending that border to be, you know, 250 nautical miles actually came after a [00:18:00] lawsuit from a patient who was on a waiting list.
And so I think it's just, it's just a good reminder for all of us, that, you know, patient advocacy really can impact these systems. and then again, the, the second piece is that it's been really nice to see in the data that. You know, as we've responded to patient needs, we're seeing that weightless mortality has gone down kind of with each increment, each change that we've made in the system throughout the years.
So that is really reassuring to see. I love
[00:18:37] Alice: that patient advocacy and including them in all of the decisions and in all of the things we do. Amy, how about you?
[00:18:45] Amy: I would say communication is just key. I think for patients overwhelmingly just spending a little bit more time if you can, and having the conversation and you know, asking if there's questions and if someone really does [00:19:00] understand, what is being presented to them.
I think that's really important. I also think it's really important, particularly with the score, that if things change, you have a conversation with the patient because the journey is. Is just chockfull of anxiety and any little change, particularly to the score, which they know is what is driving the, the transplant and when they'll get their call is, is just something that brings a great deal of anxiety.
So if there are changes, just letting the patient know immediately and just letting them know what that means. and probably also letting family members and a caregiver know too, you know, there's, there's other people as well that are very invested in this journey with them. So I think. Anytime the patient truly understands why there was a change, okay, it's better for everyone in, in the long road in terms of that patient having a, a great outcome for a transplant leading up
[00:19:54] Alice: to
[00:19:55] Amy: it.
[00:19:56] Alice: Oh, I love that. Common theme that I hear is that include your [00:20:00] patients, make sure that they understand what the recommendations are. And that we are very fortunate that in our lifetime we have seen such a big improvement to the scoring to allocate lungs. This is fa fascinating. Thank you both so much for talking to me today for ATS Breathe Easy podcast.
I had the absolute. Pleasure and privilege to talk to Dr. Mary Rodi and Amy Skiba for today's episode. Thank you so much.
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