CLE Care of Aortic Disease: BAV & Ascending Aneurysm

Podcast Transcript

Announcer:

Welcome to Cleveland Clinic Cardiac Consult, brought to you by the Sydell and Arnold Miller Family Heart, Vascular and Thoracic Institute at Cleveland Clinic.

Milind Desai, MD, MBA:

Good morning, everybody, and thank you for coming, joining us globally. So, I shall be talking about what we do before the patient ends up in surgery and beyond. So, this is a 48 year old patient I shared with Lars Svensson, asymptomatic, but active duty firefighter, incidentally detected dilated aorta as part of his calcium score preventative screening. Echo revealed also bicuspid aortic valve as shown on the echo images and without significant AS or AI. His contrast enhanced CT showed an aortic aneurysm, aorta reaching about 4.8 centimeter. He was not a big guy. His aortic area to height ratio was a little over 10-centimeter square per meter. We will discuss that briefly. So given his high-risk occupation and all the ramifications related to that shared decision making, long story short, he underwent a successful aortic valve sparing root replacement and ascending aortic replacement. He is doing well.

Milind Desai, MD, MBA:

So, the syndrome of bicuspid aortic valve, this comes in different flavors. This is from a most recent publication in JTCVS. The most common scenario, obviously, is the middle one, the typical valvular aortopathy where there's valve disease, there's aortopathy, it occurs in young adults, requires surveillance, and may require treatment. At risk for endocarditis as well as dissection. On the other end of the spectrum is the complex scenario with many genetic syndromes or congenital heart disease may have aortic coarctation and the downstream ramifications related to having complex disease. And the third one is you're going around your merry life, no issues till somebody listens to you or somebody does an echo, and they find some simple condition. These may result in a lifelong silent condition or some downstream ramifications as folks get older.

Milind Desai, MD, MBA:

So, imaging in BAV, it's a two-pronged story. You have to delineate the valve part of the story. Is it nothing? Is it mixed valve disease? Is it predominantly AS or predominantly AR? And echo, obviously, remains the mainstay, but sometimes in heavily calcified valves it gets difficult to ascertain what type of valve pathology there is. So, I've just shown an example of a 4‐DCT, sometimes 4‐DCT, nowadays, is increasingly being recognized as something that can help to be a tiebreaker when you want to really know what type of bicuspid valve there is. So, the phenotypes, these are various cartoons, phenotypes of BAV, again, the valve part of the story, the most common is the fused bicuspid aortic valve, which occurs in about 90 to 95 percent of them where the most common is the right to left cusp fusion, and the least common is the left and noncusp fusion.

Milind Desai, MD, MBA:

Then, once you have this fused BAV pattern, you may want to look at, from a surgical planning perspective, whether or not the cusps are symmetrical or very asymmetrical, and this follows a spectrum. The less common is your two sinuses, the true BAV that people used to talk about, which occurs in about five to seven percent of BAV patients, and again, is it a lateral-lateral or an anteroposterior two sinus bicuspid valve? And the third one, obviously, is the forme fruste where there is only partial fusion. So, I like to call it functionally bicuspid looking, but be that as it may, it behaves as a bicuspid aortic valve.

Another important aspect is recognizing, understanding, and quantifying calcification, especially because it has an implication on whether you're going to be able to repair the valve or you are talking about replacement, and that may help with the timing of the procedure. And in the world of TAVR now, emerging world of TAVR, there's increased emphasis being placed on quantifying aortic leaflet calcification, and that has some prognostication in ascertaining is it severe or not? So, some things important to keep in mind.

Milind Desai, MD, MBA:

Additionally, as I alluded to, average age for pure AR is in the 40s and AS is in the mid to late 50s, maybe in 60s. And if you look carefully in the literature, about half the patients at about 25-year mark will require aortic valve surgery. AS occurs in 60 to 67 percent of patients. Aortic dilation, about, if you look for it carefully, about 40 percent of patients. AS I mean, AR is about 15 to 30 percent of patients. And mercifully, congestive heart failure occurs in a significantly lesser proportion of patients. Endocarditis occurs in about two percent of the population and mitral valve in a similar proportion. Now for whatever it's worth, the bottom right panel shows data from Mayo Clinic, which suggests if you have a raphe versus no raphe, there are prognostic implications. Well, take it for whatever it's worth.

Milind Desai, MD, MBA:

The other aspect of the story as it relates to BAV is aortopathy, and this is an example of another patient in my practice who basically has a BAV, no question about it, but his bigger presentation was a significantly dilated aorta and a family history of dissection. So how do you handle this person? Clearly, he needs a valve sparing root replacement, a root and ascending aortic replacement, and the aortopathy comes in different flavors. The most common is ascending phenotype. The next available in terms of frequency is root phenotype, and then you could have a full extended phenotype.

Milind Desai, MD, MBA:

Now the question is, is this the chicken or the egg situation? What comes first? Is it both of them have a genetic predisposition or severe aortic stenosis drives aortic dilation? We don't really know. My personal biased belief is that this is mostly genetic predisposition rather than the other way around. Assessment of aortopathy echo remains the first line, and there is various different ways of measuring Z-scores, but there are some limitations of echo. Echo is very dependent upon the quality. You have to make sure you are doing accurate measurements, otherwise you're going to be off. Z-scores are generally only available for aortic root, not the ascending aorta, and obviously body surface area. So, indexing it to body surface area is affected by obesity. So at least at our organization, we rely heavily on tomographic imaging, and we are big proponents of indexing the aortic size to your aortic area to your height because that tends to remain relatively static in life.

Milind Desai, MD, MBA:

So the other important aspect is contrast-enhanced CT angiography. Every world class bicuspid aortic valve and aortopathy deserves a good tomographic scan. That's my strong belief, at least once. CT is available and rapid, and it can image the entire extent of the aorta. It is crucial. It is crucial to make sure these are ECG-gated techniques. You do not want motion artifacts in the ascending aorta, and in the rightly selected cases, CMR can also provide cardiac magnetic resonance, can also provide the same type of data.

Milind Desai, MD, MBA:

Right and a wrong way of doing things. I put this on purpose. That's not an inadvertent error. That was by design. So, beware of artifacts. The last thing you want to do is get a call from your friendly aortic surgeon in the OR that you send a patient for dissection repair, and that's just an artifact. This is the importance of gating. The other is these fake measurements. This person has a tortuous aorta. The bottom right is the right way of measuring the aorta. If you measure it a different way, this is 118 millimeters. In reality, it is truly not. So, you have to be very careful how you're measuring these aortas.

Milind Desai, MD, MBA:

The other, and this is something that we do very diligently, we strongly believe diameter alone is not sufficient and indexing it to, creating an area using multiplanar reformatting and indexing it to height provides incremental value beyond just diameter. And this is our data, folks who underwent surgery where if your area-to-height ratio is greater than 10, they did better versus the ones where we relied only on diameter. CT can also be used for preoperative planning. Doug and Eric and our colleagues, they do a lot of minimally invasive stuff where imaging can help precisely identify the location of where we are going to do minimally invasive aortic surgical approach.

Milind Desai, MD, MBA:

MRI, there's emerging roles where there are some abnormal hemodynamic flow patterns using 4D MRI and differences depending upon the type of cusp abnormalities you have in bicuspid aortic valve. This is still a research tool, but hopefully applications down the road may be forthcoming. So, guidelines, what do they recommend in bicuspid aortic valve? Typically, without risk factors, it is more than 5.5, but more than five centimeters with risk factors. At the Cleveland Clinic, pretty much this is a center of excellence. For the most part, we would generally recommend surgery based on a combination of two things, reaching more than five centimeters or if your area-to-height ratio is more than 10 centimeters, especially if you have a good surgical team, which we do.

Milind Desai, MD, MBA:

So, there are some organizations that have reported that the observed versus expected mortality in the setting of bicuspid aortic valve is slightly worse. And the panel figure D suggests that even if you get operated, your outcomes are worse compared to general population. At the Cleveland Clinic, much better. Our outcomes, if you're evaluated and operated at the Cleveland Clinic for your full spectrum of bicuspid aortic valve and aortopathy disease, your outcomes are very similar to age and gender match population. So, to end, I will say love of aortic valve may or may not last forever, but aortopathy stays with you forever. So, what you need is, like your 401K plan, you need a 401A plan. You need a long-term plan, not just to follow up your advanced aortic repair, but family screening and all the ramifications of that. So, thank you so much.

Moderator:

Thank you very much Milind, and next up is Patrick Vargo, one of our newer colleagues in the aortic surgery group here at the Cleveland Clinic who's going to talk to us about the intraoperative surgical perspective. Patrick is probably wishing that most of his practice was bicuspid valve and ascending aorta rather than redo arches.

Patrick Vargo, MD:

Thank you for having me today. I'm going to talk a little bit about the intraoperative perspective. These are my disclosures. So, when to replace the ascending aorta, Dr. Desai just discussed much of this, and the guidelines are five and a half, or if you're at a center of excellence and you're low risk, five centimeters, or if you have risk factors such as family dissection, so I won't belabor that point.

An important other measurement, though, is that if you're going to surgery for another indication and the ascending aorta is five and a half, or sorry, four and a half centimeters, and you have a bicuspid valve, that is also an indication to replace that area of aorta. And similarly, as discussed, a cross-sectional area-to-height plays heavily in our role for decision making with the threshold of greater than 10 centimeters squared per meter on cross-sectional height ratios.

Patrick Vargo, MD:

So elective aortic replacement is safe. So, a study out of here, we looked at almost 2,000 patients. If it was an isolated aortic procedure, the mortality was less than about a half a percent. The aneurysm size for that population was just over 52 millimeters, and if it was a multi-component operation, other than just the ascending aortic replacement, the mortality was two and a half percent. So elective aortic replacement is safe and can be done safely. But how much aorta do you resect?

Patrick Vargo, MD:

So as another study, looking at the different phenotypes of ascending aorta of aortopathy in a setting of bicuspid valve, there's largely three different phenotypes, a roof phenotype, an ascending phenotype, and then a more distal ascending proximal arch phenotype, with the roof phenotype being generally in younger males and the arch phenotype being in older aged patients, with the arch even being in more advanced age and often as a right non fusion. So how much aorta to resect is largely driven by where the ascending aortic aneurysm is. If you have a root aneurysm, you replace that versus the ascending and the arch. So that really drives it.

Patrick Vargo, MD:

Now if you have a distal ascending or proximal arch aneurysm, you may not have adequate aorta to clamp to do this without doing a circulatory arrest. So that's an important consideration. When I am preoperatively evaluating a bicuspid apathy, I'm looking at, "Is this a surgery I can do with a clamp, or do I need to do circulatory arrest and a hemiarch, or maybe a more extensive arch repair?" Similarly, you look to the root and is the root dilated? Is the root aneurysmal, does that need to be addressed? Is it greater than the four and a half millimeters in a low-risk patient? And if you are going to commit to a root operation, you need to make decisions about the valve as it is inherently part of the root itself. Is it a salvageable valve? Is it a valve that needs to be replaced? And these are discussions to know ahead of time to discuss with the patient.

Patrick Vargo, MD:

If the root is asymmetric, and often in these bicuspid valves, it is a bit asymmetric, the non-coronary cusp can sometimes be excised and the tongue extension of the ascending graft can be tailored into the root as well, so that you remodel the root without doing a complete root replacement. Sometimes there's an opportunity to do that. Due to the location of the ascending aorta, right behind the sternum, it's amenable to minimally invasive strategies. For mini ascending, sometimes even hemi-arch with or without an aortic valve, we can replace these with a mini ascending hemisternotomy incision. It's been shown to be equally safe, low complications, it's cosmetic, the patients like it, and it also decreases the ICU stay, the hospital stay, and overall costs to a healthcare system.

Patrick Vargo, MD:

So, once you've decided to go to surgery and you're going to replace the ascending, you also need to make a decision about the valve, and you need to assess the valve. Much of this can be done preoperatively, as shown in the previous talk. You can assess for calcium on the CAT scans. You can assess for leaflet mobility on the echo or MRIs. So, a lot of this is done preoperatively, but also an IntraOp assessment is important as well. Sometimes subtle amounts of calcium relief thickening aren't appreciated preoperatively, and it needs to be closely inspected. Things that would make me replace the valve is if you have calcification, if you have a component of stenosis, if the leaflets are thickened and not mobile, these are all not likely to lend themselves to a definitive and durable repair. If you're going to replace the valve, have to have a preoperative discussion with the patient.

Patrick Vargo, MD:

A tissue valve, as we all know, you don't require any coagulation, but there's limited durability, and the role of TAVR and valve and valve TAVR continues to change this discussion. But in the end, the valve will have a limited durability in shelf life if you replace it with a tissue valve. Mechanical valve is another option, and it's often discussed heavily for young patients, but it comes with a burden of anticoagulation, lifelong bleeding risk, as well as re-operations for things like pannus growth, and it's not necessarily guarantee that they won't be back for another open-heart surgery.

Patrick Vargo, MD:

Increasingly, there's discussion about Ross procedure, but in the setting of an aortopathy, there's concerns about a congenital genetic component to the connected tissue and the durability of the autograft as well as the presence of severe aortic regurgitation being a predictor for autograph failure. Now, if you do look at the valve and it does meet those checkpoints where you don't have significant calcium, you don't have large disruptions in leaflet fenestrations and perforations, and the leaflets remain mobile, this is the valve that's salvageable, irreparable, oftentimes. Bicuspid valve repair with the ascending replacement, it's often making a prolapsing leaflet meet and coapt the other side evenly. The annulus is oftentimes normal in this situation. The root is normal in this situation, and you're adjusting the length of the conjoined leaflet.

Patrick Vargo, MD:

So, here's some techniques shown here, and I'll show them again on the next slide as well. The raphe often be freed up, and sometimes it's a little bit thickened and it can be debrided a bit and then plicated to shorten that leaflet-free edge. Also, supracommissural or subcommissural stitches or a figure-of-eight stitches can hitch up the commissures and improve coaptation for this kind of a valve. Looking at these valve repairs, over 10 years of freedom from reintervention is about 80 percent, and those that were reintervened upon had a very safe operation with zero mortality and very low complications. If you have an aortic root that needs to replace with a valve that's salvageable, such as aortic root dilatation or aneurysm, or you have aortic annular atresia as well, that requires a total root replacement with a valve-sparing operation that preserves the native leaflet tissue.

Patrick Vargo, MD:

Just shown here is a mobilization around the leaflet, or around the annulus on the outside to dissect down there so the subcommissural stitches can get placed, the subannular stitches can get placed under there and really tighten up any annular atresia that you have when you seat the cloth tube over the existing valve. So, here's a picture of a completed modified David procedure in a valve-sparing root with somebody with a bicuspid valve. As you can see, those leaflets look healthy. There's no calcium. They're not thickened. The valve has been reoriented to 180 degrees, and the raphe plicated, usually with a running locking stitch. The valve commissures have been re-suspended, and there's small supracommissural stitches there to improve coaptation.

Patrick Vargo, MD:

So, this really combines the traditional tricuspid valve-sparing root with the techniques of bicuspid repair to give a competent valve that doesn't require lifelong anticoagulation, and hopefully will provide better durability than a tissue valve. So, in conclusion, elective aortic surgery is safe, could be safely done. If you're going there for surgery and you're going to be operating, you ought to consider replacement of any aorta that's greater than four and a half centimeters at the time of surgery. And then if you're able to preserve the native valve, you avoid any coagulation and potentially provide a durable result to the patient. Thank you.

Announcer:

Thank you for listening. We hope you enjoyed the podcast. We welcome your comments and feedback. Please contact us at heart@ccf.org. Like what you heard? Subscribe wherever you get your podcasts or listen at clevelandclinic.org/cardiacconsultpodcast.