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Intro: UAB Med Cast is an ongoing medical education podcast. The UAB Division of Continuing Education designates that each episode of this enduring material is worth a maximum of 0.25 AMA PRA Category 1credit. To collect credit, please visit UABMedicine.org/medcast and complete the episode's post-test.

Welcome to UAB Med Cast, a continuing education podcast for medical professionals. Bringing knowledge to your world. Here's Melanie Cole.

Melanie Cole: Welcome to UAB Med Cast. I'm Melanie Cole. And today, we're exploring ascending aortic arch repair and endovascular treatments. Joining me in this panel is Dr. Adam Beck, he's a professor and Director in the Division of Vascular Surgery and Endovascular Therapy at UAB Medicine; and Dr. Kyle Eudailey, he's an assistant professor and a cardiothoracic surgeon with expertise in complex aortic surgery at UAB Medicine.

Doctors, I'm so glad to have you join us today. Dr. Eudailey, I'd like to start with you. I'd like to start with you as the development of endovascular stent grafts in the descending aorta have significantly reduced the number of open surgical repairs being performed, tell us a little bit about the ascending aorta. Is it considered one of the last frontiers of endovascular aortic treatment? How prevalent is it for other providers? What are ascending and aortic arch aneurysms?

Dr. Kyle Eudailey: Sure. So, I think framing it as the last frontier for endovascular stenting is a good way to think about it. We have come a very long way in the field of endovascular repair of aneurysms, really kind of starting back in the '90s with treatment of descending thoracic aneurysms.

The trouble really becomes is that we've learned that the arch and even more specifically the ascending and the aortic root is really a very different animal in terms of how the aorta is structured. The arch has all the flow to the head vessels, which sort of complicates treatment of arch pathology. And then the ascending Is really a dynamic structure where you have significant amount of change with the cardiac cycle. And the ascending aneurysms, as you get more proximal towards the heart, are intimately connected to the aortic valve structure and the coronary arteries, which ultimately perfuse the heart.

So really, what it comes down to is that the anatomy is more complex. And because of that, it's not this concept of just a straight tube that you can slap a stent in. Unfortunately, you have to respect the anatomy of the head vessels and you'd have to respect the anatomy of the aortic valve structure and also the coronary perfusion and that ends up being tricky, would be the easiest way to describe it.

Melanie Cole: Well, I'd like you to expand on that because it was my next question. So challenges, what are some of the limitations to that current practice of ascending stent grafting?

Dr. Kyle Eudailey: So the limitations really, I mean, I guess the easiest way to describe it is how do we classically repair ascending and arch aneurysms? And classically, it's done by open surgery. And we use cardiopulmonary bypass and actually colder temperatures in order to achieve circulatory arrest where we actually don't perfuse the body for periods of time in order to protect the brain. And we resect and reimplant the perfusion to the head. And then, as we get down towards the aortic valve and the coronary arteries, we often are either resecting the valve or sometimes we spare the valve, but we're often then reimplanted the coronary artery.

So really it is a lot of difficult technical surgery. And so in order to do that all endovascularly, you really have to come up with some novel ways to either bypass the head vessels or fenestrate for the head vessels, or we have some now newer technologies that allow us to respect the anatomy of the arch while maintaining perfusion during the stenting process.

As you get down towards the valve, we also have endovascular solutions for the valve, which are transcatheter aortic valve replacement, which we're kind of starting to explore how we can treat the aortic valve and route in conjunction with stenting. That's probably just beginning to scratch the surface of what that all entails, but it gets to the fact that there's a lot of complex structure and anatomy that we have to respect.

Melanie Cole: Well, certainly. And Dr. Beck then, why don't you talk about some of the new technologies or protocols standards or even diagnostic tools for the treatment that you feel are worth talking about and how have advances in radiologic imaging really augmented your capabilities to treat these conditions?

Dr. Adam Beck: If I can maybe just back up just for a moment, just to reiterate a couple of things that Dr. Eudailey said. So some of the limitations of doing endovascular repair in the ascending aorta and arch of the aorta are anatomic and some are physiologic. And we also really should talk about a couple of different disease processes just to parse it out a little bit more.

So the operations that we do, that the cardiac surgeons do in the ascending and arch are most commonly for aortic dissection and for aortic aneurysm and both of those have their own considerations for doing an endovascular repair. And just an isolated ascending aneurysm or dissection is much different than a dissection or aneurysm that extends through the arch of the aorta for all the reasons that Dr. Eudailey mentioned about the brachiocephalic or head vessel perfusion.

From my standpoint, I have had a longstanding interest in complex endovascular aortic surgery and mostly for the thoracoabdominal aorta, for the portion of the aorta that has branch vessels to the intestines and kidneys. That is still a frontier in many ways. But the ascending and arch of the aorta have some technological anatomic physiologic challenges that we don't have in the visceral aorta. But we've learned a lot from the visceral aorta in the way that we treat branch aortic diseases. And so some of those techniques and technologies are being applied in the arch appropriately or inappropriately and we're sort of learning that as we go.

From an imaging standpoint, there've been many advances in imaging along the way since we started doing endovascular aortic repair. Some of them were preoperative, that's with the way that we do CT arteriograms and use 3D reconstruction for preoperative planning. But we've also made a lot of advances in the operating room with 3D overlay imaging where we can actually fuse the patient's intra-operative imaging to their preoperative CT scan, which is almost like playing a video game in a way, because we can actually overlay their anatomy and we can see it on the screen while we're placing the devices into the aorta.

And the next frontier from an imaging standpoint is actually non-fluoroscopic imaging, so non-radiation-based imaging where we don't actually even have to perform fluoroscopy while we're deploying the devices in the aorta and revascularizing the branch vessels. And that's actually not too far down the road. We're going to be one of the first institutions in the world to have access to that. So we're pretty excited about that technology that's coming down the road.

Melanie Cole: Dr. Eudailey, can you give us a little overview of technical aspects you'd like other providers to know about as you have expertise in these complex surgeries? What would you like to share with other providers to help achieve better outcomes? And you can speak at this time as well about patient selection and how important that is in this case.

Dr. Kyle Eudailey: Sure. I mean, I think you really kind of are hitting the nail on the head speaking to selection right? And Dr. Beck just talked about all the advances we have in terms of preoperative imaging. But really the reason that's important is because preoperative planning, it plays a major role in these cases. The variability in anatomy between patients can be pretty significant. And that variability means that there's not a one-size-fits-all solution for most of these patients. And so there's a lot of preoperative planning and selection that happens on the front end. And I think that's probably the most important aspect to understanding how we apply these sort of newer technologies to patients.

The other thing to consider is that open surgery is actually a very good option for people. And so there's a high bar that we have to overcome with open surgery. And so these people that we think we'd get the most benefit or gain the most benefit from endovascular solutions are the people who are higher risk for open intervention. And those are people who have existing cardiopulmonary disease or other co-morbidities that make their recovery harder because the open repair of these operations. And by open, I mean, a true open heart solution, which usually requires a sternotomy and several hours in the OR. It's just a big operation and people get through it, but the recovery can be hard. And so it's a better long-term solution for younger patients. But it's sometimes not the best solution for older patients. And so the preoperative planning, the patient selection, that kind of deciding who is going to benefit the best from some of these technologies based upon their comorbidities and also their anatomy is a really important step to how these technologies get applied.

And Adam and I have conversations all day and night about these people and whether or not they're anatomically suitable and whether or not this is the right way to move forward. And often, the scrutiny for them to get into some of these trials is hard too is what is I would say.

Melanie Cole: Dr. Beck, you touched on this a little bit before, but TEVAR or thoracic thoracic endovascular aortic repair, how has it helped to make ascending TEVAR a more reproducible, reliable procedure? Tell us a little bit about the success rate of what you gentlemen are doing at UAB Medicine. How have been your outcomes?

Dr. Adam Beck: TEVAR has been around a little while. Usually, when we say TEVAR, we're talking about the descending thoracic aorta, as you alluded to. That really has almost completely replaced open surgery in the descending thoracic aorta, as far as isolated surgery or that isolated segment of the aorta. The outcomes are excellent. The morbidity or complication rate and mortality of those operations is much less than an open surgery.

Thoracoabdominal aortic surgery is becoming more and more endovascular, although we still do a lot of open thoracoabdominal surgery for various reasons. Some of those that Kyle pointed out in younger patients are those with connective tissue disorders or infectious processes. As I think both of us alluded to earlier, the ascending aorta is a lot different because of maintaining coronary flow, maintaining the structure and function of the aortic valve. But also it's a very dynamic portion of the aorta, just because of the cardiac motion, respiratory motion. So it's a really demanding area of the aorta when you put a device that's made out of metal and fabric into it. So those devices can fatigue, they can fracture, they can be displaced, they can migrate and all of those things can lead to a failure of your repair. So those are challenges that biomedical engineers are working on, but we also work on in terms of our patient selection.

So it's a very small subset of patients that we actually would do an endovascular repair in the isolated ascending aortic pathology. And this is not a segment of the aorta that I operate on as a vascular surgeon. That's a segment of the aorta that cardiac surgeons operate on. And so that's why this collaboration is so important because I do a lot more endovascular surgery. Dr. Eudailey does all of the open surgery in that segment of the aorta. So we work together to try to pick the best patients for the best procedure for them.

Really the short answer to your question is we're still not doing a lot of ascending aortic repair. There are certain patients with certain conditions that are actually pretty straightforward in that segment of the aorta, but a vast majority of those patients in 2021 are still best served with an open operation.

Melanie Cole: Well, thank you for that. And I'd like to give you each a chance for a final thought. Before we do that, Dr. Eudailey, based on what Dr. Beck was just saying about your collaboration and given the complexity with increasingly complex treatment algorithms that are adding new options to your armamentarium of available therapies, how important is this multidisciplinary care, this collaboration between different specialties for these complex patients?

Dr. Kyle Eudailey: Yeah, I would say that this type of collaboration is everything. I mean, this is what makes something kind of this special possible here at UAB. There are not a lot of centers across the US that are even close to doing this type of collaboration and certainly not a lot that are even applying it as frequently as Dr. Beck and I are. And it really makes our decision-making better on both ends. What it has allowed is that it allowed us to be a part of some very exciting trials and development and things coming down the line from what Dr. Beck was saying in terms of biomedical engineers in these companies.

In 2021, we are kind of using this in a very small selected group of patients, but there is an exciting pipeline of technology to where this should be more widely available. And we are really on the cusp of it here. And one of the only reasons we're on the cusp of it here is because this type of rapport exists between us to where we can say, "Is this open? Is this endo? Let's consider this. Let's consider that" and that is a unique aspect to what's going on here at UAB, which I think is exciting.

Melanie Cole: This whole episode is fascinating to me. So Dr. Beck, first last word to you here. Tell us a little bit about any promising new therapies, any game-changers that you see coming down the pike and down the horizon, and really what you'd like other providers to know, any clinical trials or research you're doing at UAB.

Dr. Adam Beck: Well, I'll tell you, one of the most exciting things about us is I've been in practice for about 11 years now. And over that 11 years, I've seen this transformation of open aortic surgery into endovascular aortic surgery. And I've kind of watched this march towards the aortic valve. And the really exciting thing to see is that we're getting there and we're actually having successes and we're seeing devices in clinical trials. So as of right now, there are actually multiple clinical trials that allow us to treat the arch of the aorta, to treat the ascending aorta that we're right on the cusp of having available to us at UAB.

And I will also point out and it would be remiss for us not to say this, but we also have a really nice collaboration with the cardiologists here at UAB. So as we move even closer to the aortic valve where the coronaries arise, it will be very important to have them involved as well. And this is not just a virtual collaboration. This is a real collaboration. We all actually enjoy being around each other and talking about these clinical problems, which is really a pretty special thing that we have here that I don't think people appreciate elsewhere.

Melanie Cole: Dr. Eudailey, last word to you. What would you like other referring physicians to know about when you feel it's important that they refer to the specialists at UAB Medicine and anything else you'd like to share?

Dr. Kyle Eudailey: I think the important thing for people to know is that there are some exciting options here and they will work for some patients who are higher risk for traditional options. We're pretty honest about who it may work for and who it may not work for. And what we do we have available here is truly kind of amazing. And we're one of very few centers in the United States who have all these options available and I think that it's important for people to understand that especially in the Southeast, that we're always happy to evaluate people and we try to be pretty quick and responsive and the evaluation could be turned around pretty quickly for these patients, which is sometimes people worry that it takes a while for them to kind of be fully evaluated, but we're usually pretty good about having a pretty decent turnaround within a couple of days in terms of whether or not we think somebody's going to be feasible. And we also have a very good system of remote review of images, which I think is excellent, and either of our offices can set that up for referring providers.

Host: Great. Thank you so much, gentlemen, for joining us today. And a physician can refer a patient to UAB Medicine by calling the MIST line at 1-800-UAB-MIST. And that concludes this episode of UAB Med Cast.

For more information on resources available at UAB Medicine, visit our website at UABMedicine.org/physician. Please also remember to download, subscribe, rate, and review this podcast and all the other UAB Medicine podcasts. I'm Melanie Cole.