Transcription:

Melanie Cole (Host): Welcome to UF Health Med Ed Cast with UF Health Shands Hospital. I'm Melanie Cole and I invite you to listen as we examine surgical repair of the bicuspid aortic valve. Joining me is Dr. George Arnaoutakis. He's an Assistant Professor in the Division of Cardiovascular Surgery at the University of Florida College of Medicine.

Dr. Arnaoutakis, I'm so glad to have you join us today. Help us to understand the epidemiology and clinical features of bicuspid aortic valve syndrome. Is there a heritable component to this disease? Tell us a little bit about it.

George Arnaoutakis, MD (Guest): Well, good morning, Melanie. It's nice to be here this morning. Sure. Bicuspid aortic valve disease is actually a very common condition. It's technically the most common congenital abnormality, but it is seen so frequently in about one in a hundred individuals that I consider it a normal variant. It affects, as I said, one to 2% of the general population and is associated with other conditions like ascending aneurysms, coarctation of the aorta, and even a higher incidence of bacterial endocarditis.

Host: Well, then give us a little evolution on the history of bicuspid aortic valve repair. What's happened over the last 10 to 15 years?

Dr. Arnaoutakis: So, bicuspid aortic valve repair has kind of followed a similar trend that was seen in mitral valve repair, which was pioneered by a French Surgeon, Dr. Carpentier. And many of the techniques and principles that he established for mitral valve repair have been applied to bicuspid aortic valve repair over the last one to two decades, where we adopt many of the same principles toward approaching the aortic valve in terms of aortic leaflet pathology, as well as aortic annulus pathology.

Host: What an interesting topic we're discussing here today. So, let's speak about diagnosis, Doctor. How and when is this usually found and what region of the aorta is most effected by aneurysm in patients with bicuspid aortic valve syndrome?

Dr. Arnaoutakis: So, many patients with bicuspid aortic valves will be identified based on a physical exam at their general practitioner, their internist or cardiologist office when a murmur is heard. Other patients will often be identified because they have a strong family history as this is a heritable condition. And patients with bicuspid valves can develop either aortic stenosis or aortic insufficiency. Many patients will also develop pathology of the ascending aorta, where they develop a concomitant ascending aortic aneurysm. The interesting feature about patients with bicuspid valves, is that the rest of the aorta is most frequently normal, such that the main component involved is the ascending aorta.

Host: Wow. So, then review for us the current guidelines for surgical intervention. What are the clinical criteria? Tell us a little bit about how that discussion comes about.

Dr. Arnaoutakis: So, when a patient is found to have a murmur, oftentimes this is followed up with an echocardiogram, which evaluates the function of the aortic valve, as well as the other valves in the heart. And in addition, the function of the left ventricle and the other chambers of the heart. Now, if patients are symptomatic, such as shortness of breath or lower extremity edema, presyncope even angina or chest discomfort, and it's attributable to aortic stenosis, then those patients meet the highest strength recommendation for surgical intervention, a class I indication. But other patients may be asymptomatic. And that's where the conversation becomes even more nuanced about the decision regarding timing for surgical intervention. If patients start to exhibit any signs of ventricular dysfunction, such as a low ejection fraction or dilation of the ventricular dimensions on echo, that's also an indication for intervention to address the aortic valve. Which if the valve is stenotic or calcified, most often requires replacement. When patients have an incompetent or insufficient valve, that's where the discussion arises regarding options for valve repair.

Host: Well, I think one of the most important messages or aspects of our conversation today is patient selection for aortic valve repair. So, speak about patient selection and what's the most common orientation of the fused leaflets in patients with bicuspid aortic valve.

Dr. Arnaoutakis: So, there's many different anatomic variants for bicuspid valves. This is referred to as the Sievers classification of the anatomic arrangement of the bicuspid valve. Most patients will have a fused leaflet. Some patients, actually a minority of patients with bicuspid valves will have no fused leaflets and truly have just two leaflets. And that's a Sievers type 0. Patients with Sievers type 1 is the most common variant and there's most commonly fusion of the left and right coronary cusps. And that's the most common variant that we see for bicuspid valves. Now, patients who have good leaflet tissue, no calcification, those are the patients who are the ideal candidates for a valve repair.

In addition, when we consider a patient for a valve repair, it's not just the anatomic criteria of the valve, but also the patient's underlying physiologic condition. So, elderly patients with multiple co-morbidities need a more straightforward operation with a definitive outcome at the first attempt in the operating room. And so in those patients, we often undertake performing a replacement right off the bat. But patients who are younger, in better physiologic shape, are better able to tolerate longer periods under anesthesia and on cardiopulmonary bypass because the elaborate repair techniques often take a bit longer. And so those are the patients that we typically pursue repair on.

Host: Well along those lines, then give us an overview of technical aspects and predictors for successful aortic valve repair. Are there any technical considerations you'd like to share with other providers for better outcomes? Or do you have any valve preferences you'd like to discuss?

Dr. Arnaoutakis: Sure. So, patients, as I said, who have really good leaflet tissue, now they may have what's called leaflet prolapse, where one of the leaflets is longer than the other and hangs below it into the left ventricle outflow tract. And is what leads to the valve leakage. Now there are techniques such as leaflet plication where we can shorten the length of the leaflet and make it equal with the other leaflet. So, that way they meet or co-opt in the center and render the valve competent. Patients with that pathology have been found to have very good long-term durability with freedom from reoperation greater than 90% at 10, 15, 20 years out from operation. Now, one of the predictors of a failed repair, is patients who have calcification on the leaflet or patients who require any kind of a patch repair due to a defect in the leaflet. Those have been predictors of a poorer long-term outcome. So, if we encounter any of those conditions at the time of surgery, that's usually an instance where I would elect to perform a valve replacement. Now, the discussion about what kind of valve to replace the aortic valve with has also evolved over the last decade with the advent of TAVR technology, where valves can be replaced through the groin. Especially if someone has a prior bioprosthetic valve. Typically in patients 65 or younger, who can take a blood thinner like Coumadin, we recommend a mechanical valve. Patients 65 or older, the typical recommendation would be for a bioprosthetic valve.

Host: Tell us about your outcomes, doctor.

Dr. Arnaoutakis: Yeah. So, here at UF Health, we have great outcomes with bicuspid aortic valve repair. As I mentioned, one of the common techniques is leaflet plication. Many patients with bicuspid valves will also have concomitant aortic aneurysm. And one of the techniques that was actually devised here at UF Health by one of my partners, Dr. Thomas Martin is called the Florida Sleeve Technique where part of the aneurysm at the aortic root is buttressed by a Dacron graft, Valsalva graft on the outside of the aortic root. And sutures are placed underneath the annulus to anchor that graft in place and perform an annuloplasty. Then we reattach the aortic wall to that Dacron graft and that accomplishes what's called valve resuspension.

And so we've have a very long experience with bicuspid valve patients who undergo this Florida Sleeve Technique. And it's been found to be a very durable technique for bicuspid valve repair. This is an added tool in our armamentarium to address patients with bicuspid valve pathology. Other options for bicuspid valve repair are what's called a David reimplantation or a valve sparing root replacement, where we preserve the valve leaflet, but replace the entire aortic root.

Host: Well, then tell us about some promising new therapies. Are there any game changers in your field right now?

Dr. Arnaoutakis: Well, one of the newest technologies over the last decade, as I just mentioned a moment ago, is TAVR technology. And this is really predominantly reserved for patients who have stenotic aortic valves. And it was initially felt that the atomic configuration of a bicuspid valve would preclude safe TAVR performance in a patient with a stenotic bicuspid valve.

However, we have experience here at UF Health as do many other institutions around the country and world, in fact, with performing TAVR procedure in patients with bicuspid valve. What we've found is that to accomplish a safe TAVR procedure, we have to pay a little bit more attention to some of the different measurements that we use on our preoperative CT scan to look at the orientation of the valve leaflets, the native valve leaflets, that is. We also find that we more commonly perform what's called a balloon valvuloplasty before we deploy the TAVR valve. That's to allow the TAVR valve to sit more nicely in the aortic annulus and lead to very low rates of paravalvular leak as well as good hemodynamics on the valve. In fact, our experience with bicuspid valve TAVR patients was one of the first publications regarding this topic in the literature, on TAVR.

Host: Absolutely fascinating. As we wrap up Doctor, what would you like other providers to take away from this episode and your experience at UF Health Shands Hospital?

Dr. Arnaoutakis: Well, I'd like for others to know that patients who have incompetent bicuspid valves that are severely regurgitant are very commonly candidates for repair. And there's a lot of benefits to repair. Always preserving one's own native leaflet tissue, we feel is better than any kind of a prosthesis, whether it be mechanical or biologic. The rates of endocarditis are much less in a repair situation than in a person who has a prosthesis in place. And so many patients are candidates for repair techniques. These techniques are elaborate and not performed at all centers. And so we have a vast experience with bicuspid valve repair here at UF Health. And so I would just advise providers to consider that patients with incompetent valves may be candidates for repair and our bioprosthesis options are also evolving rapidly. There's new INSPIRIS technology, which has an anticalcification property. And there's some feeling that that valve may be a biologic, but more durable than the currently most widely implanted ones. And so, technology is continuing to evolve in terms of our techniques for repair, as well as the bioprostheses and mechanical prostheses that are being implanted.

And so it may be the case that someday in the future, patients with a mechanical valve don't require Coumadin as they previously have. So, there's lots of exciting developments. We have a comprehensive bicuspid aortic valve program here at University of Florida College of Medicine in Gainesville, where we offer patients the benefits of genetic counseling, cardiologists with vast experience with bicuspid valves, genetic testing and counseling for patients and families as well, as well as a very robust experience in treating patients with aneurysms throughout the entire aorta.

Host: Thank you so much, Dr. Arnaoutakis for joining us today and sharing your expertise. To refer your patient or to listen to more podcasts from our experts, please visit UFhealth.org/medmatters for more information, and to get connected with one of our providers. That concludes today's episode of UF Health Med Ed Cast with UF Health Shands Hospital. Please remember to subscribe, rate and review this podcast and all the other UF Health Shands Hospital podcasts. I'm Melanie Cole.