DocTalk Podcast: TAVR Insights with Tsuyoshi Kaneko, MD

Few advances in recent years have been as impactful and widely embraced as a standard of care as transcatheter aortic valve replacement (TAVR) for the treatment of aortic stenosis.

Less than a decade after its initial approval from the US Food and Drug Administration, the revolutionary therapy has completely changed the way cardiologists approach treatment of aortic stenosis.

Treating aortic stenosis treat once meant patients needed to undergo a surgical aortic valve replacement—requiring open-heart surgery, stopping the patient’s heart, and a lengthy inpatient recovery process. TAVR has revolutionized this process, and become first-line therapy for many patients with severe aortic stenosis.

Instead of open-heart surgery, patients have an artificial valve placed in the aortic valve through the use of a catheter, typically placed in the chest or leg. Less than a decade after its approval, the procedure patients undergo can take less than an hour. Most are able to go home within a couple of days.

In fall 2019, Tsuyoshi Kaneko, MD, cardiac surgeon at Brigham and Women’s Hospital and assistant professor of surgery at Harvard Medical School, took part in an episode of the DocTalk Podcast to give his perspective on TAVR and where he sees is progressing in the future. Since that episode, a slew of new data and studies have emerged offering greater insight into TAVR than ever before.

In this episode of the DocTalk Podcast, we discuss recent data from major medical journals to late-breaking sessions at the American Heart Association 2019 Scientific Sessions to find out what has changed and where he sees the role of the procedure as we learn more about the procedure and associated outcomes.

HCPLive: Hello, and welcome to the doc talk podcast. I'm your host, Patrick Campbell, editor with HCPLive, and today we'll be discussing TAVR with Dr. Tsuyoshi Kaneko, of Brigham and Women's Hospital. For our loyal listeners, you'll know that our very first episode featured Dr. Kaneko and we also discuss TAVR.

Now, we'll be discussing things that have happened in the last 6 months. So, I'd just like to say, Dr. Kaneko, welcome. If you could give our listeners a brief background on your experience then we can dive into our discussion.

Kaneko: Sure, my name is Yoshi Kaneko and I go by Yoshi Kaneko. I am the surgical director of the structural heart program at the Brigham Women's Hospital and I'm also the director of outcomes research at our division as well. My expertise is in transcatheter work. I was trained in cardiac surgery and also in cardiology, so I do have the expertise and I actually practice both in my daily cases.

HCPLive: Thanks for that. And as I mentioned to our listeners, Dr. Kaneko, has joined us on the podcast before about six months ago to discuss TAVR. And just to start since we had our last discussion, AHA has occurred and more relevant studies have come out examining TAVR. In your opinion, what do you think is the most significant new data to emerge since the last time we spoke?

Kaneko: Patrick, I think the biggest change that we've had over the past 6 months, definitely we're still feeling the impact by the FDA to approve the low-risk patient for TAVR. I think that has that is the most single impactful thing that has happened because what that means is that right now, TAVR was approved for high-risk patients or patients who are not eligible for surgery, and then subsequently got approved for intermediate-risk patients.

Now it's approved for low-risk patients—meaning that it's approved for all risk patients, meaning that it's approved for all comers. So, now our job which we are having a very difficult time doing is to figure out which patient is more suitable for TAVR and which patients are suitable for surgical aortic valve replacement, because as you can sort of guess nobody wants open surgery, but we believe that there is a population that will benefit still from an open surgery. And you know, to identify that particular population is very difficult and very challenging.

HCPLive: Now, that brings me to one of my other questions though, and as we've seen a lot of these TAVR studies that we're seeing at AHA and being presented are based on procedures, let's say in a time span between like 2012 and 2015. or most of these studies, though, don't include data from the most recent years and as we know, TAVR has really become more streamlined and become a much more efficient procedure.

Do you think that we'll still continue to see improved outcomes like we've seen? Or what do you think the most recent data, when it becomes available will tell us about TAVR and who it's appropriate for?

Kaneko: Yeah, I mean, some of the most recent data are available with the recent trials. And obviously, the outcomes look much, much better. Number one, because you know, we're doing a better job, but also we're seeing much, much lower risk patients. So, we are going to get better outcomes with those patients in some of these trials compared to the outcomes that were reported in 2012 and 2015 during that time period, it's incomparable. I mean, the outcomes that we do for these low-risk patients, the stroke risk of 0.6%, operative mortality of 1%, less than 1% in 30 days, all these are just completely different from what we have seen in the past.

So, I think the TAVR procedure has become safer and better, safer and safer. And it's very easy to use as well for the procedure list and because it's so easy to use, and because it's so safe to use, I think the general consensus becomes, "oh, why don't we just do it on everybody?". And I think that's some of the things that that we sort of have to stop brakes on because most of the patients will definitely benefit from this minimally invasive procedure, but not everybody. I will have to emphasize that.

HCPLive: Right, thank you for that. And now, I want to also touch on a study that you took part in analyzing the utility of 30- versus 90-day outcomes as a performance metric for hospital rankings. And now I think one of the important questions that study raised is sort of where do we balance between the appropriate outcome measure for performance on TAVR versus the extra time and effort needed to evaluate over those long periods.

Kaneko: Yeah. So basically our study showed that that the 90 days correlates more than the 30 days outcome to the 1-year outcome. It sort of raised the question of the validity of getting all the follow-ups in 30 days, which is currently required by the TVT registry. So, the TVT registry collects all the data on patients who had transcatheter valve procedures, and they mandate follow-ups at 30 days and 1-year, but the follow-up rate at 1-year becomes substantially lower compared to 30 days. It also does put a lot of burden on the programs. You have to make sure that they follow up in one year and not all of them are reachable because some of them come from remote access and that really becomes a problem.

Our question really has become would 90 days be able to substitute you know, both 30 days and 1-year and minimize some of the burdens that there is for a routine follow up. I think this question is still wide open, because as you sort of mentioned prior this study uses the data from 2012 to 2015. So, these were mainly high-risk patients, and for low-risk patients, would this be true? We still don't know I think we have to find out with more recent data that comes out in the future.

HCPLive: Thank you for that. Now, one more thing I wanted to touch on in regard to sort of the new information about the nuances of TAVR or surgery, one that we had previously discussed, that came out of AHA was this analysis of the France-TAVI registry. Self-expanding valves were associated with increased risk.

Obviously, this wasn't a randomized controlled trial examining this was a sort of a retrospective look at it, but what did you take away from this study? And this is a bit of conjecture but is this something that you've seen in your experience doing TAVR for so many years?

Kaneko: You know, I think this is a very, very hard data to interpret because you know, they use administrative data from the French France registry and they retrospectively propensity-matched and tried to make it into an equal group and then compare the 2 which show the superiority in some of the outcomes of the balloon-expandable valve, but there are a lot of things that are hidden behind these statistics.

So, say, for instance, core valve, the balloon expanded self-expanding valve has some features that benefit certain anatomies. Say for instance, they can accommodate smaller vessels. So, if you have an iliac vessel that is not accommodating a balloon-expandable valve, a self-expanding valve may be feasible to do that.

Currently, we may be including more patients that has smaller iliac, which is not really captured by this administrative database. Moreover, if your institution is mainly doing balloon-expandable valves, the cases where you pick to do the self-expanding valves may be those that are extremely challenging that are not accommodating balloon-expandable valves. So, therefore, we may be including all these high-risk cases in there. And I just can't think of a way to completely exclude those biases and compare the 2 because this is not a randomized control study.

So, I think this is very provoking. The balloon-expandable valve may have lesser paravalvular leak and may have lesser mortality, but until we have a randomized control study, I don't think we can say that for sure. People are interested, but I don't think this was the format to completely answer that question. And this is just question provoking at this point,

HCPLive: Some more data that's come out very recently, I think it was published just earlier this week in NEJM relating to the timing of a SAVR procedure, and that how it impacts outcomes. It found that early surgery was associated with better outcomes than a conservative approach. Now, just from your experience, how does the timing of a TAVR or SAVR surgery related to the appearance of symptoms impact outcomes for aortic stenosis?

Kaneko: Just to clarify, Patrick, I think you're talking about the Korean study that looked at the surgical aortic valve replacement and am I quoting the right paper from New England Journal medicine?

So, that study particularly looked at early intervention become the for the patient becomes symptomatic, and had shown some benefit. The traditional teaching on aortic stenosis is that you wait until you're symptomatic because you sort of have to balance the risk and the benefit ratio, there's a benefit of doing an operation to prevent harm from the aortic stenosis. But you do risk your patients undergoing open-heart surgery.

So, you sort of had to scale that, that risk and the benefit ratio and come up with an equation and all the guidelines currently state that you operate when the patient is symptomatic, but this paper sort of challenge that dogma, saying that, maybe we should be doing the surgery earlier. And it sort of makes sense—you don't want your heart to be burnt out before you actually intervene on the valve.

There's actually an ongoing clinical trial sponsored by Edwards Lifesciences, called Early TAVR trial, which is randomizing patients who are asymptomatic into TAVR versus medical management. that outcome, I think, will be the most impactful one—understanding whether early Intervention really has a benefit or not. So, I think there is more increased interest in this subject, but I think we have to wait until this trial is completed for us to completely understand whether early intervention is truly useful, especially in the transcatheter realm.

HCPLive: I agree, I definitely think it's something to keep a close eye on as we go forward. And now just lastly, I wanted to touch a little bit on post-TAVR treatment, the GALILEO study and some other things that have come out look towards the impact of care following TAVR and how it impacts outcomes long term. Now, I just wanted similar to the very first question, what do you think has been the most impactful study or new data to come out regarding post TAVR care?

Kaneko: So, GALILEO definitely is one of the impactful ones because there has been a heightened interest regarding post-procedural valve thrombosis that was first reported by the Cedars-Sinai group when they were performing clinical trials for cortical valve. And there were concerns about these valvular thrombosis causing thromboembolic episodes or causing an early structural valve deterioration.

There was a presentation that was done at TCT looking at the PARTNERS 3 trial CT substudy analysis—this has not been published yet—but what they showed was that valve thrombosis that was seen or detected on the CAT scan at 30 days, some of them resolved without being on anticoagulation, which was thought to be one of the golden standard treatments because the original article stated that anticoagulation reverses those valves thrombosis.

In the most recent GALILEO trial, there's a CT substudy that actually showed that patients who are on NOACs have less chance of developing valve thrombosis. However, in the main trial, the GALILEO trial showed that being on NOACs actually has more harm than the benefit of the anticoagulation itself. They had a higher chance of mortality, and nobody can really beat that. So, routine use of anticoagulation after TAVR is basically axed because of this clinical trial.

I think we will have to learn a little more about the effect of valve thrombosis. I know that Medtronic will be presenting their low-risk trial data on valve thrombosis at this year's ACC. So, we're going to learn more about this but I think we're going to need more numbers and longer follow-ups to see the true effect of the valve thrombosis? Would it really be affecting the thromboembolic rates? Or in the long term, would it truly be affecting the structural valve deterioration?

I think those are the 2 questions that we don't know yet. And whether anticoagulation really is applicable for these patients. Despite the PARTNERS 3 CT substudy remains to be seen. I think a lot of the clinical practices still anti coagulate when we see these valve thrombosis post procedurally.

HCPLive: All right. Thank you for that insight. I totally agree. I definitely think it raises a lot of important questions. And just before we go, were there any other studies that you wanted to touch on that I might not have touched on during our conversation?

Kaneko: I think there's more and more data being published at this year's ACC. I sort of mentioned about the Medtronic sub-study for the valve thrombosis. There will also be data presented on the bicuspid aortic valve, which is another frontier that we truly do not understand at this point.

So, you know, in general, TAVR has established itself as a standard of care for aortic stenosis patients, but I think we're going to have to dig in deeply more and more to each subgroup to know the true nature or the true benefit of this. I think ACC is going to be a great start. We're going to see more and more in these subgroup studies that are truly important.

HCPLive: Yeah, I think it's just really incredible how quickly it's become standard of care and how much we still have to learn about it and how much it really seems like we have area for improvement, but I just want to thank you again for taking the time out of your busy schedule to speak with me today. And I hope to have you again on the DocTalk Podcast.

Kaneko: Thank you so much, Patrick.

HCPLive: All right. Dr. Kaneko. Thank you again, and to our listeners. That's it for this episode. The DocTalk podcast. Thank you for listening.