Aortic stenosis: recognition, referral and advances in TAVI

[00:00:00] Welcome to the The Clinical Round podcast. This is general information for health practitioners only, and you can claim the time as part of your CPD. Welcome back to the Medical Forum podcast with me, Dr Joe Kostrich, GP and clinical editor of Medical Forum. And today I'm pleased to be joined again by Dr Matt Clifford. Gerald, thanks for coming in and spending some time on the podcast today. Thank you, Joe.

[00:00:29] So we did speak, I think we worked out it was over a year ago, but time goes very, very quickly. So for those who might not have caught the initial podcast last year, and you obviously can go back and listen to it, or who aren't familiar with you, just before we get into talking about aortic valve disease and aortic stenosis, just tell us a little bit about your own background and what you're doing at present.

[00:00:52] Dr Joe Costridge, Ph.D.: Yeah, sure. So I'm an interventional cardiologist at, I'm based in the public at Fionnestani Hospital, though I have my own solo private practice at the moment. At Fionnestani Hospital, I'm the director or the clinical lead, as you call it for the valve intervention program, and the structural heart program. So I do all the transcatheter treatment for, you know, heart valve disease, and also for a lot of structural heart disease.

[00:01:18] So my area of interest is obviously sort of, you know, in a lot of valvular and structural heart disease. Okay. All right. And I think before we came on air, you're saying you've now got your own solo practice, which is, which has been unusual these days. So, so good on you. Dr Joe Costridge, Ph.D.: Thank you so much. Yeah. It's good to be your own boss. Dr Joe Costridge, Ph.D.: Yeah. There is something to be said for that. Dr Joe Costridge, Ph.D.: Yeah. Dr Joe Costridge, Ph.D.: And also on the other side, not have to run a whole lot of people.

[00:01:48] Again, look, it's good if you like to do it, but you can also simplify your life, which is, which can be nice. That's all obviously off topic. So again, aortic stenosis is something like, you know, I think back, you learned about it a little bit in med school, but it hasn't had a lot of airplay for many years. Obviously you hear about coronary artery disease as, you know, and that's what people think with,

[00:02:11] with hearts, certainly the general public. So is there a tendency to miss aortic stenosis? And I suppose the next thing following on from that is when I'm in the, in the practice, what can I be doing that maybe makes it less likely that I miss it? And perhaps what should I be looking for? Dr Joe Costridge, Ph.D.: Yeah, I think, yes, is the answer to the first part. And it's probably both from doctors and also from patients.

[00:02:38] I mean, yes, definitely valvular heart disease is not in the prevalence of coronary artery disease, for example, you know, in my own view. But it's, so we're still talking about three to 5% of the population over the age of 75 would have a degree of severe aortic stenosis. If you're talking about valvular heart disease in general, that percentage goes, you know, the incidence goes up to about close to 10%, still in the, you know, which is, you know, quite substantial.

[00:03:07] Dr Joe Costridge, Ph.D.: Well, one in 10 is quite substantial, certainly with our ageing population. Dr Joe Costridge, Ph.D.: Yeah. But that's involved with heart disease in general. Dr Joe Costridge, Ph.D.: Yeah. Dr Joe Costridge, Ph.D.: But ASD is still talking about three to 5%. Interesting you brought that one up because there is the WA study that was just done, I think, a couple of years ago. Dr Joe Costridge, Ph.D.: I think we were part of it, if you understand. Dr Joe Costridge, Ph.D.: You know, basically just an online survey of a whole bunch of patients over 65 and also of GPs.

[00:03:35] And what we basically have found is that about under 3% of this population, these patients are aware of heart valve disease or that it could be a, you know, potential issue for them. Dr Joe Costridge, Ph.D.: And certainly when they go to GPs, I think, what was the figure, about 60, 50, 60% of them, only about that, 40% or more, would not have had a cardiac auscultation.

[00:04:01] So to answer your second question, from a GP perspective, I think if a, especially elderly patient presents with suggestive symptoms and the suggestive symptoms are exertional symptoms, I can tease that out later, you know, the most important thing, as I always say, is it's very simple. Just have a, put your stethoscope on the chest, listen for a murmur. Dr Joe Costridge, Ph.D.: That's good because it really, it is as simple as that. If you don't listen, you don't hear a statement of the obvious.

[00:04:29] Dr Joe Costridge, Ph.D.: And yes, the symptoms are non-specific, but is there like a cluster that might make you think aortic stenosis is a bit more likely or is it really, it's just non-specific and you have to listen anyway? Dr Joe Costridge, Ph.D.: Certainly for, especially at the more, you know, in the elderly patients, any exertional symptoms such as shortness of breath, chest pain, dizziness,

[00:04:55] you should think about a cardiovascular problem and to not to miss, not just aortic stenosis. I know the topic today might be about aortic stenosis, but I would just broaden to say valvular heart disease in general, micro-reglation, for example, they all have murmurs. So from my perspective, any exertional symptoms which, you know, is from the, originate from the potential chest, shortness of breath, chest discomfort, as I mentioned, we should listen.

[00:05:21] But I would say in general, also have considered sometimes some other valve disease very off-topic a bit from AS, but say tricuspid regurgitation, for example, can give you abdominal symptoms. Dr Joe Costridge, Ph.D.: Okay. Dr Joe Costridge, Ph.D.: And in general fatigue. And, you know, you can just dose in, you know, those are the backflow problems. And some patients who present with just really tired, the abdomen's a bit, you know, discomfort, especially when they eat, you should start thinking about abdominal pathology.

[00:05:51] But a very simple, just pop a stethoscope on the chest, you won't miss it. Okay. For that one, there'll be more tricuspid regurgitation, for example. Yeah. Is it still the case that there is sort of, again, stretching my memory back to med school days, we need everything sort of strictly by the book, and I'm pretty surprised most people don't do everything strictly by the book. You'd never get a lot done.

[00:06:15] But in terms of auscultation, is it still the sort of the sitting forward at a certain degree angle? Or, you know, if somebody's sitting in the chair, if it's there, you're fairly likely to hear it? I tell the medical student, keep it simple thing. If you do sit forward and you're on expiration, most murmurs would declare. But I would say anybody with significant valvular heart disease should be able to pick up a degree of murmur. Louder doesn't mean worse.

[00:06:45] Sometimes softer can be worse, especially towards the, you know, the end stage. But they, you know, they are there. If you're maybe leading on to, you know, what to do next after you hear a murmur would be just do an echocardiogram. Back, I think, when I was in medical school, when you were in medical school, you have to remember how to tell the, you know, severity. Yeah. I think physicians do have to do that.

[00:07:14] But I would say that those probably in the era where echo is a bit more harder to get. Right now, it's easy to get. It's widely available. It's low risk. Just get it done. And you can diagnose it. Exactly. In those days, it was very much, you know, where you're hearing it, the loudest. And I'm not going to say that isn't important, but an echo can answer that.

[00:07:39] It's a bit like, remember, the neurologists would sort of work, you know, get you to work out where you think that the stroke was. And now you just send them for a CT or an MRI. And look, you know, the world changes. Correct. And it largely progresses. All right. So we've got some symptoms.

[00:07:57] Is there a case, and I think I know the answer, but I think it's still important to ask it, say for people 65 and above, even without symptoms, just doing a routine, listen to the heart every so often? And if so, roughly, how often is so often? Should not take more than a minute. Yeah. It's a simple thing to do.

[00:08:17] And the reason I say that is because the asymptomatic severe valvular heart disease, there's more and more evidence to say that, you know, you need to be A, aware of it, B, survey it objectively with serial echocardiogram, and C, there are more evidence. AS is one of them, whereby there's evidence to say you might be able to want to intervene before onset of symptoms. Which then leads to the next step, which is, all right, so we've listened, we've heard a murmur, we've done the echo.

[00:08:48] Who then needs to come and see you versus being told, you've got a little bit of aortic stenosis, there's probably nothing we need to do now other than monitor it. Where do we draw those lines? Who is it useful for me to send to you? One simple answer would be anyone with moderate valvular heart disease. That's good. I like simple. Yeah, so just try to simplify. So when you read the report, depends on how, you know, how closely you want to read the details or how, you know, simplified you want.

[00:09:17] The simplified version, look for anything that is valvular heart disease, aortic stenosis, regurgitation, microstenosis or regurgitation. Anything that's got the descriptor moderate or worse, I would think is reasonable to send to a cardiologist. We would evaluate whether it is truly moderate or worse. And it all deals then with the timing of intervention and the frequency of surveillance.

[00:09:41] Because once you've got moderate or worse valvular heart disease, current guidelines will say you should survey them with an echocardiogram. Yeah. Every one to two years. Okay. I think in the current, I think in Medicare environment right now, still requires a specialist rather than a GP to be able to order an echocard with that frequency. Yes. I think for GPs, I wouldn't swear. Every two years. I think it's every two years. Every two years. So it's more frequent than that. Correct.

[00:10:07] So then, you know, and then there are also a lot of nuances sometimes about whether something is moderate, whether something is severe. Yeah. That's the point. I mean, none of these, and we all use them and we all sort of intuitively know what it means, but none of them have any absolute, or do they have an absolute definition? Or not? They should, but that's not always.

[00:10:32] I think aortic stenosis, the valve stenosis is actually simple because there is an objective marker, which is the gradient. Okay. So speaking, they come from the Doppler velocity. So you put color on it, you can measure the velocity of the flow. Right. That gives you the velocity, which translates to a gradient. But then you get weird concepts like the low gradient, severe aortic stenosis.

[00:10:57] Sometimes, you know, they'll call it paradoxical or they'll call it low flow, low gradient aortic stenosis, which may be classical or paradoxical. Sometimes, of course, discordant aortic stenosis. Mm-hmm. All very confusing. I don't think cardiologists have difficulties teasing them out.

[00:11:14] But I guess, you know, and it's actually our, you know, reputation to say sometimes you need a valvular heart disease type, you know, cardiology team or the heart valve team to say, yeah, is this severe? Is this moderate? Is this, you know, reach a stage whereby we need to think about intervention? Mm-hmm. Or is it still continue to survey? Yeah. So there's a lot of complexity.

[00:11:39] And as a result, my simple message would be if it is a, you know, moderate or worse. Yeah, moderate or above. Yeah. Send it to us. We will work out all the rest. Is it the severity, the true severity from the moderate to the severe and the timing of intervention? Mm-hmm. And this, you know, frequency of surveillance. All right.

[00:11:59] Well, that then leads to the intervention and the TAVI or trans-aortic valve insertion, which, as I recall from our discussion last year, has become much more widely used than a decade and 15 years ago. Okay.

[00:12:16] So what's sort of changed over that time that's really put this to almost, am I correct in saying it's almost now the preferred procedure versus surgical or not quite there yet? No, it's overtaken. So TAVI, which is transcatheter aortic valve replacement. Yeah. So basically a catheter-based aortic valve replacement. It's effectively a big stent through a, you know, through the femoral artery usually.

[00:12:45] In Australia, since I'm pretty sure two or three years ago, it's overtaken surgery as the most common mode of aortic valve replacement. Okay. So sort of, again, parallel with history when coronary artery stents overtook bypass surgery. Yeah. Okay. So what's changed? I think the technology's improved, whereas previously you, you know, you're talking about mortality risk,

[00:13:12] which I think is still comparable to surgery at every single threshold. Like for high-risk patients, when we first ran the study comparing surgery versus TAVI, you know, certainly, and there's on older devices, certainly TAVI is, you know, similar mortality, if not slightly lower. And, you know, as we progress with time, the technology has changed. It's become more robust, more predictable. The sheath side, I'll give an example.

[00:13:41] The sheath, the catheter that you have to push into the femoral artery used to be 24 French. 24 French is a chest tube. Yeah. Yeah. Right now, it's 14 French, which is slightly smaller than the urinary catheter. Yes. It's still big, but it's certainly not your chest tube. Yeah. So, I mean, those kind of advances. That's a significant reduction. We know how to size the valves better. We know how to deal with certain high-risk situations like calcifications.

[00:14:11] So those have improved. And as a result, it's become a bit more of a robust procedure. And most importantly, I guess, we have now run randomized control trial comparing TAVI versus surgery in almost a whole gamut from the low-risk to the medium to the high-risk population. Actually, chronologically, it was the high-risk first. Then we moved to the medium risk. Then the low-risk part in our patients. But we have now completed all these trials.

[00:14:41] And what we... And in terms of high, medium, and low risk, that is in, like, operative risk or risk of progression of disease or risk of... Oh, sorry. I didn't make that one clear. Or the operative risk. Right. High risk means that... So high operative risk. So it's about the general status rather than the cardiac status specifically, although that obviously factors into the overall risk. Yeah, of course. So there's an operative risk patient. So high risk means the patient who are high risk of, in Australia speaking, the risk of dying from the surgery...

[00:15:10] Yeah, not getting off the table. Yeah, that's a risk. Yep. All right. Medium risk is 4%. Low risk is less than 4%. Yep. That's the... Yep. And on all of these, what we have found is that majority of the short-term complications, the death stroke is similar or maybe slightly lower with TAVI. Yeah. Bleeding is certainly a lot lower for obvious reasons. Yes. But there are certain things which are higher risk for TAVI. Okay. Pacemaker, for example, it's just to do with that.

[00:15:39] Where you implant the TAVI valve is right next to the heart's conduction system. So a higher risk of them subsequently needing a pacemaker. Correct. Of heart block. And there is a... One of the Achilles heel was the paravalvular leak, so, you know, aortic regurgitation around the prosthesis. Because we do not take out a valve. We do not sew in a valve, which is what the surgeons do. Right.

[00:16:05] We implant a valve inside a aortic valve anulus, which is a bit rocky and jagged with calcium. Okay. And so there's, you know, you could have leak. But the technology has improved. We have now a skirt around the valve that, you know, the leakage has gone down. So a moderate to severe leak is now down to about the 1%, 1% to 2% mark. Whereas previously, say, 5, 10 years ago, it was more in the 5% mark, if not more.

[00:16:34] So that's shrunk considerably from 5 down to 1.5%. Because those leaks, especially when you're moderate or worse, is associated with worse outcome. Long-term outcomes. Even just medium-term outcomes. Okay. So it's associated with worse outcomes. So we don't want to do it on more general population until we can fix those problems. Sure. Yeah. So it does that. All right. So they've done the trials initially on the high risk, then we've gone to the moderate risk, and now we've done the low risk as well. Yep.

[00:17:02] And in all three, the results were consistent? In terms of- In the long and medium term, the clinical outcomes were pretty equivalent. Mm-hmm. So that leaves the main, like certain of the complications, like bleeding is obviously going to be a lot short, lower with TAVI. And one thing I forgot to say, recovery time and hospitalization time is obviously a lot shorter with TAVI.

[00:17:29] Well, I was going to ask you that because, again, more as a procedure versus surgery, you'd expect people going home sooner, again, a bit like stents versus bypass surgery. That's the big event. That's one of the big attractions. So the post TAVI, the median length of stay in WA is about one to two days. Okay. So you're going on Monday and you're home probably by Wednesday, Thursday. Especially if you're in the public hospital system, if you understand that you're worried about, they need the bed.

[00:17:58] A lot of our patients go home the next day. And look, if you're up to it, then I'm yet to find anybody who says I sleep better in a hospital bed than in my own bed. I'm sure there might be some people out there, but yeah, you got to think being in your own bed is nice if, you know, if you can be there. Yeah. So I think that's the, so those are the, a lot of the, like what you said, stenting versus bypass surgery. A lot of the shorter term, there's a lot of certainly, you know. Uh, advantages.

[00:18:28] What's left now is just the, you know, the longer term implications, especially longevity of the valve. Yeah. I mean, as, as part of that, is it sometimes the case, you know, thinking like with, with stents, I know when people do their consents, consent, they have to agree if it doesn't, you know, work, I accept that I might have to have open heart surgery and, and bypass graft. With doing the TAVI, is it, is there also some, are there instances where one says we

[00:18:55] now need to go through to, to surgery or that isn't a thing? The incidence of that is one, is 0.5% in published data. Um, and I think our rate in this town is less than that. Okay. That's good. Uh, so every patient, it's not just a TAVI, it's just not my decision. It's a heart team decision. So they get referred to us. We discuss in our, a multidisciplinary heart team that involves cardiac surgeon, interventionalist,

[00:19:24] imaging doctors, and a lot of times also geriatricians. Um, and, um, so we decide in that meeting as well, whether the patients would be appropriate to progress to a, you know, bypass, you know, an open cardiac surgical bailout. Yeah. Um, it depends on the age of the population, you know, of the patient, the surgical risk, et cetera, um, and their anatomy. So, yes, uh, so they depend, it's case by case. So fairly rare by the way.

[00:19:53] So it's case by case, but the actual incidence is also about 0.5%. Oh, you mentioned there also with the multidisciplinary team. And that's something I found sitting here and talking to a variety of, of doctors from very, very different backgrounds, different specialties, sorry, that almost all, um, you know, almost all surgery and procedures is now sort of genuine team input rather than lip service team input. As, as part of that, is there somebody like a nurse, for example, like a cardiac nurse

[00:20:23] who also assists the patient and doing some of the interpreting and, and sort of in inverted commas holding their hand? Uh, very good question. And yes, uh, all TAVI programs in most TAVI programs in Australia and all the ones in Perth, uh, that means, you know, other, you know, each of the hospitals, uh, have a TAVI coordinator, uh, who reaches a nurse, uh, that, uh, that, uh, that's what you just said, uh, coordinates

[00:20:51] the, you know, especially as the patients do get a bit older, they, you know, there's, uh, you know, a few other testings and, you know, uh, inputs required. So, yes. So what do you need to do in advance your work up and the like? Correct. And making sure it gets done. Yep. Correct. So there's, uh, you know, um, with certainly that position is around, is, uh, is there. Um, and they also coordinate the TAVI meeting, the multidisciplinary team meeting.

[00:21:20] And then like post procedure that they've gone in on a Monday and potentially home the next day or the day after, um, what potentially might they wander into a GP practice with on a Friday that again, I should be sort of aware of and when might it be, this is okay. And when, look, you need to go back to the hospital. Ah, okay. Well, um, I guess the, firstly, the most common question I get asked is what sort of blood

[00:21:48] thinners, you know, antithrombotics they need. Bare minimum is aspirin. Okay. And I've put that loosely because certainly I've got patients that cannot even tolerate aspirin. You can run them without any antithrombotics. Uh, but what we typically do will be aspirin. But if they've got other indications for say, you know, atrial fibrillation, they need a NOAC for example. Yeah. They'll just stay on that. Um, things to watch out for from a GP perspective.

[00:22:18] Most of them are transfemoral procedures. So, you know, any potential painful groin complications. Um, if in doubt and the patients are complaining because this is one of the more common phone calls my practice get would be, I just say, do an ultrasound. Yep. You know, uh, for if there's a hematoma, get analgesic, rest. Mm-hmm. Um, what we watch out for is a studio aneurysm, vascular, you know, that would be the main things. Expectation is also important. Some patients improve in symptoms the next day.

[00:22:48] Okay. Some patients take some time. And probably the reason is because of cardiac remodeling. Aortic stenosis specifically, uh, causes left ventricular hypertrophy. And so you have a stiff heart. That can take, um, you know, about six months. No, sorry. Up to a month to six months to improve. And as a result, uh, you know, just some patients will come and say, I'm still short of breath. Right.

[00:23:18] You say, give it some time. Yeah. But I would find that most patients at one month, they feel good. Okay. And certainly by six months, they will say like, if there are no other issues, you know, comorbidity is going to impair their, their, their, their symptoms. Those, you know, they will have their symptomatic improvement. Okay. And then in terms of, of longer term followup, you do an echo after what sort of period of time? The European guidelines suggest an echo every year. Okay. I don't know if I agree with it, but I have been using, doing that. Right. Okay.

[00:23:48] And that's sort of in every year in perpetuity sort of thing? Yeah. We're looking for valve degeneration. Yeah. Um, and I suspect that's just because trans-scatheter valve is still seen as novel, even though, as you say, it's been around for 20 years now. Yeah. Um, the surgical valve, they're basically, it's five prostheses. It's, I would say, should pretty much, you argue should be on the same standard. They don't suggest any regular surveillance until maybe about five years. Okay. So.

[00:24:14] And what is the, like, what's the, the, the life expectancy of the, of the valve roughly? And I appreciate it's going to differ from person to, to person, but is there a, you know, like you say to people, you, you, you know, all else being reasonably equal, this should keep you going for up to X years? I think that's the, one of the, uh, kind of key questions, as I mentioned. Yeah.

[00:24:40] That's the, one of the very, you know, last remaining, one of the important unknowns. Okay. When does the valve start degenerating? Yeah, you were saying, we know the short and the medium term, but we're not quite at the long term yet, but we're getting it. What I quote for, you know, valve degeneration needing for re-intervention is about 1% per year. Okay. So about 10% in 10 years. There's some of the data suggesting that.

[00:25:05] And if you look at the data so far on the trials, surgical and tabi valve seems to be on the same track. There's been no, you know, there's some exceptions, but there's been no signal, consistent signal. Right. The tabi valve is going to do worse than surgical valve. But, you know, the surgeons will tell you the surgical valve life expectancy is about 10 to 15 years. Mm-hmm. Whether that's true or not, you know, you can debate.

[00:25:31] But let's just say if that's true, when that, you know, when that happens for tabi valve, which is the definition is when the bulk of it will start degenerating for off the cliff, as I say, I don't know. My belief is probably going to be the same as surgical valve. Yeah. And so I treat all bioprosthetic valve the same. I would tell them whether surgeons put it in or I put it in. I say, yeah, chances are in about 10, 15 years, it'll break. And we have to think about a redo. Yeah.

[00:26:00] And we're going to, and I appreciate, again, there's no absolute answer to this, but if you want to, you know, look at your crystal ball. You were saying before that these procedures are now being done on younger people, defined as a little less than 70, but also people are living longer. So in five and 10 years' time, will we be seeing more, you know, redo of tabbies because of those two factors, do you think? Yes.

[00:26:27] And that's one of the, we are increasingly recognizing that aspect. And the important implication is, can we do a tabby inside the, can we do a valve-in-valve procedure? So when the bioprosthetic valve fails, so a tabby is a bioprosthetic valve, it's a tissue valve. Yes. A surgeon past the age of 64, most people are past the age of 65, we put in, or even 55 now actually, we put in a tissue valve. They all have limited lifespan, as I say.

[00:26:56] And I say about 10 to 15 years. Now, they will fail. When they fail, you can do a tabby procedure and put a clansic catheter valve inside the failed prosthesis. Yeah. But there are certain issues, you know, which are unique compared to a native valve. The main one is risk of current occlusion because of the designs of the valve, et cetera. So what we increasingly realizing now is the concept of lifetime management.

[00:27:25] The key of which is when the valve, when the bioprosthetic valve fails, whether it's tabby or surgical, can we put in another one? Yeah. Because, and this is very relevant for tabby because tabby, this is, you know, there's stuff for technical reasons, higher risk with certain designs of having coronary occlusion. So we've got to now simulate having a tabby, you know, on a young patient which might outlive

[00:27:53] their tabby valve, for example, that if the valve goes in, we can put in another one. Okay. Surgical valve tends to be easier, not always, all right? Right. Depends on how the surgeon puts it in. But that's one of the serious considerations we will always have when it comes to, you know, doing tabby versus surgery on younger patients. And how do we assess that? The key investigation is a CT scan. And they will tell me the patient's anatomy.

[00:28:21] And with that, I can simulate if a valve goes in. Assume it fails. Yep. Can we put the next one in? Okay. So we were talking before, obviously, about trials and the SMART trial, sort of, before we sort of finish up today, you tell us a little bit, and I just love how they always come up with acronyms. So there must be a special division somewhere that just comes up with acronyms about the small animals.

[00:28:49] Can you just tell us a little bit about the SMART trial and what the take-homes might be for the average GP? I don't actually recall what the SMART trial stands for, but the SMART trial is a trial that compares... I think that's why we have acronyms. I think nobody can remember what it stands for. I get it. I completely get it. No, the SMART trial is one of the trials in our field that compares two types of... It's probably a bit more specific for tabby operators.

[00:29:16] It's compared to two forms of, you know, transcatheter valve. One is a supra-annular design valve. One is an intra-annular design valve. It's probably the two most commonly used valves in the world right now. And it's more relevant for people with small annulars. Okay. Now, the thing with small annulars is that when you put in a surgical or tabby valve, ultimately it's a bit like a Russian doll. You know, the hole becomes smaller. Yep.

[00:29:44] And so just say if you have a... Put in a valve that's got a bit of a smaller, you know... If they... You know, if the valve that gets put in is a small valve, then there is always a residual gradient. Even if the leaflets are working. So it's relevant for people. So for people with small aortic annulars, you know, with small anatomy, the residual gradient,

[00:30:09] the residual, you know, the residual gradient is an important issue for us to consider because we know that people who has a higher residual gradient from surgical data do tend to do worse. And that particular class suggests that supra-annular valve do tend to maybe have lower residual gradient and what they call patient prosthesis mismatch compared to an intra-annular type of valve.

[00:30:34] So it's kind of more relevant to, you know, for tabby operators, especially when it comes to choosing a valve choice. And, you know, since you mentioned that diverting a little bit, the other issue with doing with lifetime planning, which, you know, things that makes me lose sleep sometimes is your young patients with the small annulus. Right.

[00:31:01] You know, because when you put in a valve, surgical or tabby, you've got to plan carefully because if that fails, the next valve that goes in will make inside an existing, you know, bioplastesis will make that annulus even smaller. So H2R is getting a little bit smaller, like you said about the Russian doll. It's the Russian doll effect, right? So that's one of the things that we, you know, it's a very interesting field because that's

[00:31:26] one of the other areas that we need to look at for lifetime management is besides coronary occlusion is what to do for the small annulus. Yeah. And again, obviously it's not my field, but I could imagine us reaching a point where a little bit, even today, more people are likely to have stents, but some people will be told it's not suitable for you. You need to have bypass. There may be a day where most or, you know, significant majority are having the transcatheter

[00:31:53] version, but some people might be told, no, that isn't, that particular procedure isn't suitable for you. Sometimes we do have to say that. Yeah. Nothing, nothing, nothing is suitable for every single person. It's not a possibility. I mean, it's a bit, you know, this is a bit debatable and it's something we talk about in our team meeting just to get you to play what we discuss. Plus, you know, that small annulus, for example, if you give it to a surgeon, you say, you

[00:32:18] know, can you please, what the surgeon can do is that they can cut away the annulus and make it bigger. Okay. Obviously. Yeah. We can't. Yeah. So that's one of the things that they can do. It does raise the operative risk of the dependence of which surgeon you speak to, but it's, so those are the nuances now that we face with aortic stenosis. Once you get referred to us, that we now trying to figure out what's the best way forward in

[00:32:45] terms of treating you, not just now, but I guess in the lifetime, which is very relevant for the younger patients. Gerald, that's been very interesting. And even I think from last year, you know, things have changed and I suspect over the next one, three and five years as, you know, more data comes out and that's based on more procedures being done. You know, obviously like with everything in medicine, we'll know even more. So that's been really good. Before we finish up today, have you got two or three maybe key take-home messages for the

[00:33:14] Medical Forum podcast audience today? Sure. I hope it's not repeated last year. Might be. No, no, no. Because my take-home messages for GPs, I can now deny it. Those take-home messages might be similar, but you know, similar is okay. That's all right. But if these are done, you know, I think a lot of patients benefit. If it firstly, early, you know, have a listen to the murmur, especially if they have symptoms, but even just in your general routine checkup, have a listen for murmur.

[00:33:43] If there's any murmur, do a low threshold, get an echocardiogram done. The question when to refer, anyone with moderate valvular heart disease, or just AS, or the other ones, refer earlier. I mean, maybe to wrap up, I will just put a plug to what I do at Finestani, also private. Transcatheter valve is evolved definitely beyond TAVI. There's now transcatheter mitral valve intervention and tricuspid valve intervention.

[00:34:12] So we certainly can treat it, and more and more we do know that these patients, if they are not treated, and they are only on medical therapy, they don't do that well. So it is, you know, so refer to us early. And, you know, I think I got from the discussion, there are a lot of complexity in dealing with them. But GPs don't have to deal with them. Send it to us. And I'll even say a lot of times, even amongst cardiology field, a lot of, you know, unless

[00:34:41] you're in the valve disease field, you know, a lot of these are even confusing. Yeah. So send it to us. We will, you know, that's what we are here for. Take care of those problems. Sounds good. Gerald Yong, thank you so much for being on the Medical Forum podcast today. Okay. Thank you so much for the invitation. Thanks for listening to the Medical Forum podcast. Please follow and encourage your colleagues to do the same. And if you have information and knowledge you'd like to share and be on this podcast, contact

[00:35:11] the Medical Forum team.