Talking Tall Rounds®: TAVR for Bicuspid Valves

Podcast Transcript

Announcer:

Welcome to the Talking Tall Rounds series, brought to you by the Sydell and Arnold Miller Family Heart, Vascular and Thoracic Institute at Cleveland Clinic.

Grant Reed, MD:

Well, thank you guys for having me today, and thank you to the Dr. Brann family for making this possible for all of us. We're going to build off of the last presentation and incorporate some of the small annulus concepts and take it a step further and talk about how do we approach a patient with bicuspid valve in contemporary practice. I'm going to use a few cases to illustrate important concepts. This is a 68-year-old patient with class two heart failure who also has radiation heart disease, so not the same patient, but shares some similarities to the one that we're talking about today. Clearly, high surgical risk. That's one point I want to stress today is that TAVR is currently approved and is an option for patients who are high surgical risk, but we are still collecting data about the right way of managing those patients at lower surgical risk.

This patient is clearly elevated surgical risk for a number of reasons. As you can see from the trans-thoracic echo in a parasternal long axis view, severe aortic stenosis with suggestion of bicuspid anatomy, which is confirmed on CT scan. A CT scan is really very important for planning because not all bicuspid valves are created equal. Some may be in this case, as you can see as a Sievers one, almost a Sievers zero anatomy with a non-calcified raphe, whereas others may have a lot of heavy raphe calcification, and that increases the risks of paravalvular regurgitation and other issues for TAVR. This patient had a small aortic valve annulus as well with a cross-sectional area of 3.8 approximately, and as you can see, a very eccentric sinus, but a good transfemoral axis otherwise and otherwise suitable for TAVR, albeit at slightly higher risks.

So where does TAVR fit into the armamentarium of treatments for patients with bicuspid valve? I would rather frame that as to where does it fit in the range of treatments for patients based on their surgical risk and life expectancy? As we all appreciate, the current guidelines now have approved TAVR and give it a recommendation for either a class I or a class IIa recommendations in patients regardless of their surgical risk. But it's important less to think about their surgical risk and more to think about what their life expectancy is. Because if someone's life expectancy is less than 10 years and if they're high surgical risk, well then that patient really isn't appropriate for surgery.

Those are patients that we may want to push the envelope and think through, "Well, we're willing to accept a TAVR result even if it may be a slightly suboptimal outcome," whereas those patients who are low and medium surgical risk, especially those patients who are younger, we need to be thinking about getting them the best possible result with their initial treatment and also setting them up for success for the future treatment, whether that be surgery or a valve-in-valve TAVR. That is of the utmost importance and very relevant to patients with bicuspid valve.

It's also very relevant for us today to build on this and say that all the data to date is really from observational studies. We don't have any randomized clinical trial of TAVR in bicuspid valves, and that's for a good reason, is because the anatomy is higher risk. The suboptimal outcomes, although we have observed great outcomes at our institution, there is increased risk for paravalvular regurgitation, for embolization and rupture. There may a higher risk of stroke with bicuspid valves, and many of these patients need intervention for other reasons. They have ascending aortopathy or another reason for surgery. You can appreciate just how eccentric the valves can look inside of the annulus.

So a Sievers zero valve may be very favorable for a TAVR, and it may be somewhat tricuspid-like in the circularity of the annulus, whereas a Sievers one, if you have a non-calcified raphe, that may also be fairly favorable for TAVR. But the more calcification you get of the raphe and the more calcification that extends into the LVOT at the annular level, that's where outcomes can sometimes suffer. And then these are the things you need to consider, especially as you move into lower risk patients.

Fortunately now, we do have some data on lower risk patients, and the PARTNER 3 trial did include a bicuspid registry. In these carefully selected patients with low risk out to one year, we see that compared to tricuspid valves, patients with bicuspid valves actually did very well with very low risk of mortality and low risk of paravalvular regurgitation. But, again, these patients did not have heavy LVOT or annular calcification, and this is really a propensity score match analysis rather than a randomized clinical trial. Nonetheless, very high quality, well-judicated outcomes, and we see satisfactory results.

Building on this, which patients with bicuspid valve are at higher risk? Right. This is a very well-done study of about a thousand patients looking at predictors of paravalvular regurgitation with Sievers one bicuspid valve. As you can see here, there are very clear predictors of paravalvular regurgitation, and they're actually fairly similar to the general TAVR population. Those patients that have severe annular calcification, calcification which extends down into the LVOT, valves that are placed too high, this is where you see an increased risk of paravalvular regurgitation. At least in this series, self-expanding valves had a slightly higher risk of moderate or severe paravalvular regurgitation than balloon expandable valves.

So what do we know? That’s that the TAVR is safe, it's feasible, it's very effective, one-year mortality, maybe very similar to patients with a tricuspid valve, but we also don't know a lot, right? We don't know about long-term durability yet. We don't know about the risk of leaflet thrombosis or HALT. We don't know if it affects the evolution of aortopathy. But in patients who are high surgical risk, who really don't have another option, it can be a life-saving treatment, and that's what we're talking about today. Whether or not it can serve an important role as a bridge to surgical AVR or ascending aorta replacement in patients who are borderline like those patients who have radiation heart disease, that's yet to be determined.

So here's our case result. As you can see, we chose a 23 millimeter S3 valve, which had a wonderful result. This patient did have a CT scan afterwards to Dr. Griffin's point. You can just see how the valve does sit somewhat eccentrically in the annulus, but in the sinus, but nonetheless had a great outcome.

Just going to highlight two other cases, which are maybe pushing the envelope a little bit, also in high-risk patients who did not have a surgical option. This is a case of a patient who wasn't quite as favorable for TAVR, but we still did TAVR because they had no other option. Severe aortic stenosis, Sievers one with the bicuspid valve with a heavily calcified raphe with a fusion of the right and the left coronary cusps. Also had a small annulus, but in this case, we chose a self-expanding valve platform.

Because of this calcification of the LVOT into the annulus, we were worried that there could be an increased risk of annular rupture. Our plan was to land the valve slightly deeper, because of the calcification, to see if we can seal better. So we chose a 25 millimeter Navitor valve, and this is actually one of the first bicuspid valves treated with Navitor in the country. So as you can see here, had an excellent result, but needed aggressive pre-dilation and post-dilation, which somewhat defeats the purpose of a self-expanding valve because you're pushing on that calcium in the annulus.

So there's trade-offs. Although the risk of annular rupture may be a little bit less, as you see from the observational data, the risk of paravalvular regurgitation with the self-expanding valves may be a little more. So you have to strike this balance. In this case, we were able to get a great result with the 25 millimeter Navitor with gradients, which were absolutely phenomenal given a very small annulus.

Then to finish out, this is a case I actually just did two weeks ago of a patient who had a bicuspid valve, also Sievers one, but very, very minimal calcification on the valve with pure aortic regurgitation, unfortunately high surgical risk. So this was a TAVR for pure AR in a bicuspid valve, which also has higher risks for all those reasons, but good access and dimensions on the borderline, but favorable for a very oversized self-expanding valve. So we chose to do a 34 millimeter Evolut valve.

Just to illustrate some very important concepts and why this should really only be done at centers with expertise in this area, that you have to be very methodical and careful with how you place the valves. The fear is that the valve can embolize or migrate because of the lack of calcification. So it's almost counterintuitive that you want to start high with your placement because you don't want the valve to slip up, but you need to because this valve, as you can see, slid down considerably even after deployment. So we're deploying almost at zero with relation to the annulus. Here you can see after release that the valve settles considerably deeper. This is why you need to be very careful and do this at centers that are comfortable with this. Fortunately, at the Cleveland Clinic, we have more experience with this than really anywhere else in the nation.

But this patient had an excellent result for TAVR for pure AR in a bicuspid valve, did not need a pacemaker and was discharged the next day. So in summary, TAVR is safe and feasible in patients with bicuspid valve with very acceptable outcomes, but the risks are somewhat higher than tricuspid valve disease. And for that reason, it should really only be considered for patients at high surgical risk. Using it as a bridge in those patients who are lower risk who maybe have yet to develop ascending aortopathy, that can be considered. But we need to really educate patients that just because they have a strong preference for TAVR, it doesn't mean they're going to go throughout their whole life without a surgery. We're not quite there yet in terms of the data.

So I would caution us against moving into that space yet without the data, but I think it's encouraging the data that we have so far. We can do this for pure AR, even with the bicuspid valve in appropriately selected patients, but that's really pushing the envelope and should be done at a center like ours. But the heart team strategy is key. Hopefully, this series of cases highlight that it's important to have expertise in all of the TAVR techniques in order to get good outcomes for these patients.

Announcer:

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