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Melanie Cole (Host): Welcome to UAB MedCast. I'm Melanie Cole. And today, we're exploring bicuspid valve disease. Joining me is Dr. Kyle Eudailey. He's an assistant professor and a cardiothoracic surgeon with expertise in complex aortic surgery at UAB Medicine.

Dr. Eudailey, it's a pleasure to have you join us again today. So help us to understand the epidemiology and clinical features of the bicuspid aortic valve and this disease. Is there a heritable component? Speak a little bit about it.

Dr. Kyle Eudailey: Sure. Well, nice to chat with you again, Melanie. Appreciate you having me. So the bicuspid valve, I guess really first it's important to define a few things, right? So, the aortic valve, obviously last valve to leave your heart, intimately connected with the aorta, which is the largest blood vessel in your body. And so that will kind of become important later on in our discussions about treatment. So it's important to know that the aortic valve and the aorta are kind of intimately connected specifically at the aortic root by the heart.

Bicuspid aortic valve disease is really a hereditary or congenital heart defect. And it's actually probably the most common congenital heart defect. It basically exists somewhere between 1% to 2% of the entire population. So if you think about that 1% to 2% of all people, there's a lot of bicuspid valve disease out there. And so it's a relatively common disease pathology or valve pathology that we come across.

Essentially, what it means is the aortic valve normally has three leaflets. It's a tri-leaflet valve. If you look at that valve en face or in cross-section, it looks like a peace sign or a Mercedes-Benz sign. And, in terms of when you have a bicuspid valve, it simply means that you have two leaflets instead of three. That can come in a couple of different flavors, but the vast majority of them are a simple fusion of two of the leaflets together.

And what that does is it sets up the valve for complications throughout the lifetime of the valve. But that's the kind of gist of sort of what we're looking at in terms of when we talk about bicuspid aortic valve disease, we're really just talking about a two-leaflet valve of the aortic valve as opposed to a three.

Melanie Cole (Host): So when is diagnosis usually made? Since this is congenital, is this something we know from in utero or when a child is little or is this usually found in adults? Tell us a little bit about diagnosis.

Dr. Kyle Eudailey: Yeah. So, diagnosis, it can be at any time in a person's life or the valve's life. As I said, 1% to 2% of people have this. And so a lot of people live a normal life and never know that they have a bicuspid valve. Many will remain asymptomatic. If we look though at sort of the lifetime of bicuspid valves, probably 50% of people will ultimately have some complication regarding their valve or have some intervention in regards to their valve over their lifetime. And so really, the diagnosis comes about when there are symptoms or complications of bicuspid valve disease.

So the important thing to understand is that really is associated with valve dysfunction or if there's any sort of associated aneurysmal disease. And the symptoms that you have are based upon ultimately the type of valve failure that you have or our mode of failure. And so if we look at really the most common ways that these valves failed, there's really kind of three ways that we ultimately end up figuring out that somebody has a bicuspid valve or figuring out that they have symptoms from a bicuspid valve.

So probably the most common is what we call aortic stenosis. Aortic stenosis is a stricture of the aortic valve or calcification of the aortic valve. And what happens is the valve itself basically gets stiff and doesn't open as well. This is something that usually presents later in life. And so this is something that we typically see in people who are between 50 and 70 with bicuspid valves and basically the valve itself gets stiff and calcified. And what it does is it makes it to where it's harder for the heart to pump blood through that valve.

The most common symptoms are the symptoms associated with valve dysfunction, which is trouble breathing, dyspnea on exertion, fatigue, worsening exercise tolerance. Sometimes it can be associated with some chest discomfort or syncope, you know, passing out. And this is really probably the most common way in which we pick up bicuspid valve disease. So this is the vast majority of bicuspid patients.

The other ways in which we see bicuspid valves or see the symptoms or complications really or the other modes of failure, so aortic regurgitation or aortic insufficiency is basically a failure of the valve to coapt or basically means that the valve itself is leaky. And so this is something we see probably in about 10% of bicuspid patients. And this is usually seen in the younger years. So people with bicuspid valve disease, they could be teens, 20s, 30s. And what we often see are the signs of when you have a severe leaky valve. And often that means, again, decreased exercise tolerance, getting more short of breath. But typically, these people have other symptoms like palpitations or heart racing. And this is again secondary to the valve leaflets being a little extra floppy, so kind of different than the aortic stenosis patients.

And then, finally, we have patients who have aneurysmal disease and that means that you have some associated aneurysm of the aorta with the bicuspid valve. And these people can often be asymptomatic. This is typically picked up serendipitously or by some other tests for some other medical procedure. But if we look at all patients with bicuspid valve disease, probably 50% of them have some sort of associated aneurysmal disease, either of the ascending aorta or the aortic root.

And so any one of these three major pathologies of the valve can result in either symptoms or complications that ultimately lead us to heading down the pathway of treatment or setting up a surveillance program in terms of keeping an eye on something or management.

Melanie Cole (Host): Thank you so much for that comprehensive answer, Dr. Eudaily, and we're going to get into patient selection for valve repair. Before we do that, you're speaking to other clinicians, what is the importance if this is diagnosed and identified of other family members being evaluated by a physician? And how does your program identify those family members who are affected? What would you like to tell other providers about the importance of that identification for a hereditary bicuspid valve disease?

Dr. Kyle Eudailey: Sure. I think that's probably the best question that can be disseminated in a podcast, right? And it's something that's been evolving and we sort of have a better understanding of. The thing that we need to understand is that bicuspid valve disease has a genetic component. Some bicuspid valve disease can be sporadic. But we do know that the majority of bicuspid valve disease has some autosomal dominant component. And so autosomal dominant, for clinicians, we know that that usually means direct one-to-one inheritance. But the kind of complicating factor about bicuspid valve disease is that there's incomplete penetrance, right? So the heritability, it's not clear, meaning that the genes can be passed on, but it doesn't necessitate that a bicuspid valve is going to end up being present.

So, ultimately what does that mean? It means that if you have a patient who has bicuspid valve disease, really all of their first relatives should be screened for bicuspid valve disease. And so the big takeaway is that kind of point right there. And if you look at population studies or if you look at genetic studies, basically, it comes down to about 10% of first-degree relatives have a bicuspid aortic valve. So if you yourself have a bicuspid aortic valve, 10% of your first-degree relatives will actually ultimately end up having a bicuspid valve. That's a fair number of people, even if you think about how prevalent it is. Like I said, it's important that screening is kind of really considered.

And so what is screening, right? So, screening for all first-degree relatives, specifically, when we talk about screening, we mean a transthoracic echo. So were talking about echocardiography. We're doing ultrasound of the heart, specifically focusing on good views of the aortic valve as well as good views of the ascending aorta and aortic root, because what we want is a screening process to pick up not just valve disease, but also aneurysm disease. And the nice thing about echocardiography is it's a non-invasive screening method and so it doesn't require radiation or it doesn't require contrast. And the big important takeaway is this is actually an AHA or American Heart Association guideline for screening, which like I said, is first-degree relatives specifically should get a TTE or transthoracic echo.

Melanie Cole (Host): That is a key component as a takeaway message for this podcast and an important point that you made. So, what about patient selection? Because not everybody's an optimal patient for aortic valve repair, correct? If somebody is younger, you mentioned earlier aortic regurgitation, but not necessarily valve repair in these patients. Speak about how you decide and how you discuss and work with the patients and a multidisciplinary team to figure out who are the best candidates.

Dr. Kyle Eudailey: I think you hit the nail on the head there in that it's always a discussion, right? And ultimately options for intervention depend upon whether or not the patient with a bicuspid aortic valve requires a valve intervention, repair of aorta or both, right? So, sometimes it's an isolated valve intervention. Sometimes it's an isolated aortic aneurysm intervention. Sometimes it's both. And so the combinations of how we treat those patients, there's really a lot. And so I'm going to try to break it down based upon the specific pathology. But everybody's different and everybody's a little bit unique in terms of their risks and benefits of what we are able to offer.

So you touched upon valve repair, which is probably the most technically challenging and something that's probably unique to UAB. Valve repair, really this comes down to aortic regurgitation, right? So, aortic regurgitation, obviously like we've mentioned is when the valve is leaky or floppy. The valve at this point doesn't really have heavy calcification in regurgitation. And typically, this is what we see in younger patients. So the issue here is we have younger patient population and if we are considering intervening on the valve, really we're trying to think about the lifetime management of the valve. So particularly in patients who are in their 20s, 30s, 40s, they have a life expectancy of 30 to 50 years and really, we need to find a solution for them for that long of time.

The issue with valve replacement in these people is that tissue valves just don't last that long. These are valves that are made of cow tissue and pig tissue. Unfortunately, these valves actually fail sooner in younger patients. And so, typically, in young patients, a tissue valve may not last more than seven to ten years, honestly. And so that's really not a great solution. So the only other option for those patients for replacement is a mechanical valve. The trouble with a mechanical valve is that they're then bound to anticoagulation for the remainder of their life.

So in a lot of these patients, as long as the valve has decent tissue, and it's not too calcified, we're actually able to provide an aortic valve repair using the natural tissue. And what this does is it gets the intended result where you have a functional valve that it works well. You are able to do it with natural tissue and often you can have a longevity or the valve will last longer than a tissue valve and honestly, in a lot of cases, as long as the mechanical valve, except you do not have to take blood thinner. That's a real win for younger patients. And like I said, that's something that can really only be achieved in places where valve repair is done often, and that's high-volume valve centers or valve referral centers.

The next pathology we're going to talk about is aortic stenosis. This is something that we know a lot more about or treat more often, partly because we see aortic stenosis with normal tri-leaflet valves. But that being said, aortic stenosis with bicuspid valves is just slightly different in terms of how we treat it. Really the option for this is aortic valve replacement. Again, this is a little bit easier to deal with because often these patients are in their 50s and 60s. That being said, in your 50s and 60s, you still may have 30 years ahead of you in terms of life expectancy. And so we have to have some of these same conversations about tissue valves versus mechanical valves. But for this population, really replacing the valve is the best option.

Now, in the aortic stenosis population, we have to consider the classic surgical aortic valve replacement verse the newer transcatheter valve replacements. This is kind of interesting topic because transcatheter aortic valves, these are valves that are placed in through the leg and that are done through endovascular techniques. This is the sort of standard of care for tricuspid aortic stenosis. But there's this ultimate question about, do we treat bicuspid valves using transcatheter techniques?

At this point, the important thing to know is that in all of the pivotal trials that approved transcatheter valves for use, bicuspid valve patients were excluded. We do have some larger observational studies where transcatheter valves have been used on bicuspid valve patients. And we do know that it's possible to use them on bicuspid valve patients, but these are typically older bicuspid valve patients. So these are people in their 70s, 80s, which is probably a slightly different flavor than the people who get aortic stenosis in their 50s and 60s.

At this time, I would say again, the best thing is for people to be evaluated at a high-volume valve center. And that's because what that allows is multidisciplinary teams sort of make the best decision regarding how to best treat the valve. We do know that bicuspid valves often are more calcified or sort of more heavily calcified than tricuspid aortic valve stenosis. And so for those reasons, we still believe that in younger patients, an open surgical valve replacement is really the best option. The other reason for that is, when that tissue valve fails, those people are set up for success because they can get a transcatheter valve inside of their surgically replaced valve. And so they are set up for sort of this long-term success of their valve, where you have a surgical valve replacement, and then you have what's called a valve-in-valve TAVR in the future. Now, this is still an area of study where we're kind of trying to figure out if we can move the needle and treat younger patients with transcatheter valves. But at this time, we still lean a little bit towards surgical valve replacement in younger bicuspid valve aortic stenosis patients.

The sort of final option for treatment that I had mentioned is patients who have an associated aneurysm or aneurysmal disease, and that can come with a valve problem or without a valve problem. If you have a valve problem and you have an aneurysm, you're not a candidate for any of the transcatheter therapies. If you have an aneurysm and you don't have any valve disease, meaning you have bicuspid valve, but it's working very well, then your indication for treatment is really dictated by your aneurysm. And that's a whole different discussion, but basically what we do is we kind of decide what's the risk-benefit of either continuing surveillance imaging, meaning just keeping an eye on your aneurysm first and intervention. And ultimately, we make a decision about what's the lowest risk option, meaning is it less risky to prophylactically treat the aneurysm and replace that? Or is it less risky to just keep an eye on it and continue with continued surveillance imaging or repeat scanning or ultrasound imaging?

So, as you can see, it can get complicated quick, and that's because you have to put together all the different pieces of bicuspid valve disease and the associated lesions that come with it, which most notably are usually aneurysmal disease.

Melanie Cole (Host): Well, you made it very clear and your indications were really understandable. You're a great educator, Dr. Eudaily. No, truly you are. And for other clinicians, this was all excellent patient selection information and complications. So as we wrap up, any game-changers that you would like to mention? And I'd also like you to just let other clinicians know when you feel it's important to refer to a high-volume valve center, as you said, like UAB Medicine.

Dr. Kyle Eudailey: I think the big thing is if a bicuspid valve is identified, it's important to set up the screening of the first-degree relatives. I think that's kind of probably the biggest takeaway for physicians. But I also think that if somebody has a bicuspid valve and there's any concern for an associated aneurysmal component, it's reasonable for them to be bumped up to a cardiologist or even a cardiothoracic surgeon in order to set up a plan of how to monitor this moving forward.

Obviously, I'm a cardiothoracic surgeon. I think the biggest thing for me is I always tell people, just because you're sending somebody to a surgeon, it doesn't mean that they're going to get surgery, meaning that part of what I do in my clinic is I see a lot of aneurysmal patients and so what we do is we set up a plan of how to continue surveillance, how are we going to move forward. And we also discuss with patients what are the triggers as to when we would consider surgery or what ultimately means we're going to undergo surgery.

And so, getting a plan earlier in the patient's course is really important and understanding that just because you're sending somebody to either a cardiologist or a surgeon, doesn't necessarily mean that you're committing them to an intervention, which is really the other important thing.

Melanie Cole (Host): Well, it is. All of this information is fantastic. And I'd like you to come on with us again and talk about some of the specifics of those various repairs that you were discussing earlier.

Dr. Kyle Eudailey: One more public service announcement is that anybody who has a bicuspid aortic valve, even if it's functioning well, is actually at slightly higher risk of getting an aortic valve infection or what's called infective endocarditis. And so we actually recommend usually that these people have prophylactic antibiotics before dental work and things like that, which is important for primary care people and for cardiologists to know about their patients who have bicuspid valve disease.

Melanie Cole (Host): That's an excellent message to let them know. So thank you so much.

And a physician can refer a patient to UAB Medicine by calling the MIST line at 1-800-UAB-MIST or by visiting our website at uabmedicine.org/physician. That concludes this episode of UAB MedCast. Please remember to subscribe, rate and review this podcast and all the other UAB Medicine podcasts. I'm Melanie Cole.