Expertise in Bicuspid Valve Repair Part 1

Podcast Transcript

Announcer:

Welcome to Love Your Heart, brought to you by Cleveland Clinic's Sydell and Arnold Miller Family Heart, Vascular and Thoracic Institute. This podcast will explore disease prevention, testing, medical and surgical treatments, new innovations and more. Enjoy.

Lars Svensson, MD, PhD:

Hello, I'm Lars Svensson and I'm the Chief of Heart, Vascular and Thoracic Institute. With me today is Brian Griffin. He's our Vice Chair for the Institute and also a leading imager. When I say imager, I’m talking about particularly an expert on echocardiography and all aspects of that. We look forward to chatting to you today about bicuspid valves, what causes them to deteriorate over time, although not always known, what the symptoms potentially are, what we look for in treating patients with bicuspid valves and what the options are. So, Brian, let's just start off with a broad introduction to bicuspid valves and our understanding of bicuspid valves and the genetics, if anything, about bicuspid valves.

Brian Griffin, MD:

Bicuspid valve is the most common form of congenital heart disease that we see. Normally, the aortic valve has three leaflets that open and close, and open in the form of a triangle. It seems like that's the best hemodynamic form of the valve. But in about 1-2% of the population, either only two leaflets develop, or more commonly two leaflets fuse in the womb and the patient or the person is left with two leaflets.

This is a very wide spectrum in terms of the severity of the problem. In some people, the fact that the leaflets, that they're only two of them, they don't open that well, can cause problems in pediatric and adolescence. In others, they may get through a whole normal life without really very much problem. It's estimated that maybe up to 50% of people who have a bicuspid valve may not have any serious problem with it.

But it is so common that we see it an awful lot, and it can give rise to three separate things that we think about. One is the valve leaflets, because there are only two of them, they open like a buttonhole and they don't open fully, so you have narrowing of the flow of the blood leaving the heart. When this is severely narrowed, as can occur at any time in life, but more commonly in people in their fifties and sixties, this leads to tiredness and eventually to shortness of breath.

Another group of patients will have predominantly leaky valves. In these, we often see that in the two leaflets that are formed, one is bigger than the other. The bigger one tends to prolapse or drop down more, and therefore it doesn't make as good a seal with its opposing leaflet as it should. There's a lot of leakage.

This type of problem is one that we often can repair, if the leakage is severe, rather than replace, and we'll talk about this a little bit later. Cleveland Clinic is one of the world leaders in this type of procedure.

The final major complication of this is that in about 40-50% of people who have a bicuspid valve, the aorta, which is the big tube that comes out of the heart to carry blood, is not quite as strong as it should be and enlarges over time. In many people who have a bicuspid valve, this enlargement can become sufficiently severe that there's a risk of tearing the aorta. It may require an intervention to shore up or to replace that portion of the aorta which is abnormal. Fortunately, this usually just involves the first part, or the ascending part, of the aorta, but this is something that we look at as well.

These are the three big things. There are other things we could talk about as well, but these are the big three that we think of in bicuspid valve. Lars and I see hundreds of these patients with these problems every year.

Lars Svensson, MD, PhD:

Just to add a couple of points to what Brian was saying and what I touched on. Unfortunately, when it comes to bicuspid valves, gene mutations that are associated with causing bicuspid valves are rarely found in patients with bicuspid valves. The one is the NOTCH1 gene, but it's pretty rare and we screened a lot of our patients and it's hardly ever seen. However, 9% of patients who have a bicuspid valve may have it in a blood-related relative. As a general rule, we recommend if a family member is found to have a bicuspid valve, it's not unreasonable for other blood relatives to get screened for bicuspid valves.

The one group of patients that we are very worried about is the patient who has Loeys-Dietz syndrome. Those are genetically defined mutations that have been well studied and known. There's a belief that bicuspid valves are more common in that population. But from personal experience, I have not seen it as commonly as it is described in patients with Loeys-Dietz. We wrote up a series of 63 patients with Loeys-Dietz a few years ago. Our series is much bigger now because we do a lot of valve re-implantations in these patients, and so we see the valves whether they have three leaflets or they have just the two leaflets of a bicuspid valve.

Let's move on to now, what are you suggesting and what are you discussing with your patients based on their age, what you're recommending as far as the valve? So, as you know, typically younger patients, it's a regurgitant valve. As you get into forties, fifties, we start seeing the patients with bicuspid valve and stenosis. What are you recommending for patients now as far as valve replacements or repair?

The stroke rate is higher with TAVR (transcatheter aortic valve repair) and bicuspid valves. The paravalvular leak rate is higher.. The root is very different and the valve symmetry apart from the actual shape of the root is different in patients with bicuspid valves. That's partly the reasons why they don't do as well in bicuspid valves, apart from the fact that patients are typically younger too and then come back with problems related to TAVR in bicuspid valves.

What are you saying to your patients and what are you discussing with them based on age and long-term lifelong management of their valves?

Brian Griffin, MD:

Certainly, a lot of what I do, I certainly see a lot of these patients at various ages. I think when somebody is over the age of 60 and they have a stenotic valve, or probably even a regurgitant valve, the bioprosthesis has a good track record. They have the potential for doing a valve-in-valve in the future. What we usually try to ensure here is that, for somebody like that, the last procedure they have is a TAVR-type procedure, that they have that when they're relatively old, when open surgical procedures might be somewhat more uncomfortable or risky for them. The bioprosthesis that we have typically used at the aortic position have been bovine pericardial. We have a series of over 12,000 patients that showed probably better than expected durability with those types of valves.

In younger patients, people who are in their twenties or thirties, it is always a trickier problem. If you go with the bioprosthesis, you're potentially exposing them to multiple future operations and procedures. One way of trying to get around this is to put in a mechanical valve. When I came here first 30 years ago, at least half of the valves we put in were mechanical. Now, I would say about 10% or less of the aortic valves we put in are mechanical.

Some of that is change in population, but some of it also is the improvement in bioprosthesis and people's distaste for being on an anticoagulant. Particularly people who have occupations or whose idea of fun is to go off on an off-road bike, mountain biking or things like that, where they're exposed to risk. Although a mechanical valve is a very good option for younger people, I find that not that many people want to go that route. The results with mechanical valves have been very good and some of the mechanical valves that we've had, the early ones, can last for a very long time. What we try and do here is to educate the patient as to what's available and then help the patient make their own decision as to what's best to do.

There are other approaches in younger patients, one of which would be to put in a homograft valve, which we tried for quite a few years. That's a human valve, but that wasn't associated with better long-term outcomes. Or to do the Ross procedure where you take the patient's own pulmonary valve, put it in at the aortic position where it's possibly most needed, and then put in a human valve at the pulmonary position. It's a big operation, it's a two-in-one operation. The results of that in bicuspid valves have been not always that favorable, particularly in patients who have aortopathy. So, it had fallen in favor and then out of favor. It's making a little bit of a comeback, but we don't have long-term data to suggest that that is something that we should do.

Here too, we have the ability to do the Ozaki procedure. It's a Japanese technique where the patient's own pericardium is taken and made into a bioprosthetic valve, the advantage being that it's the patient's own native tissue that's being used. Again, we don't have long-term data on the success of that.

One thing that I've liked over the years in younger patients who have a very leaky valve, and particularly where they have a big prolapsing leaflet, where the leaflet is not very stenotic and where there isn't a lot of calcium on it, is to try and repair the valve. I will ask Lars to explain how that's done. But our results with repair have been quite good, with certainly durability, in many instances, as good, if not better than a bioprosthesis, and yet leaving the patient with their own valve. I think bicuspid valve repair in expert hands is a very good technique.

I have had patients who've had this done where the repair has lasted longer than 20 years. Eventually though, even with the repair, the valve will often be no longer leaking, but eventually may calcify and become stenotic and then require another intervention. But for a young person who doesn't want to be on Coumadin and who wants to maintain a relatively normal lifestyle, I think a bicuspid valve repair can be a very good option.

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