Dr Clare Appleby (Liverpool Heart and Chest Hospital, Liverpool, UK) revisits the latest data and discusses whether transcatheter aortic valve implantation (TAVI) should now be considered the default treatment for patients with symptomatic aortic stenosis over surgery.
Has TAVI evolved to become the default treatment for patients with symptomatic AS? If not, what more is needed to convince you?
Should this apply to all approved valves?
In which clinical settings would a patient not be a candidate for TAVI and how do you assess this?
Does durability still need to be assessed alongside factors such as coronary obstruction, longer term?
Filmed in London at BCIS ACI 2020.
Interviewer: Leiah Norcott
Videographer: Natacha Wienand / Dominic Woodruff
Transcript Below :
Question 1 : Has TAVI evolved to become the default treatment for patients with symptomatic AS? If not, what more is needed to convince you?
[Appleby] I think it's a little bit early to say it's the default strategy for all patients with symptomatic aortic stenosis. I don't think anyone's going to argue about the high-risk group. There's a lot of data for intermediate risk and, obviously, there's the trials published last year in the low-risk group. So, I think it is, certainly, the way we practise in a more elderly population, which are the vast majority of people who are going to present with symptomatic aortic stenosis, TAVI is a default strategy in the older age group. I think if we're going to look at evolving it into the truly low-risk population the things that people are concerned about, certainly, our surgeons are very concerned, is durability. We've got 12 month data, that's not long enough, especially when we start getting into younger age group. And, of course, the low-risk trials, although they were a low-risk population were actually elderly population, over the age of 70. So, I think, really we need to look at durability. And then, looking at the younger profile patient. It's a little bit early, in my view, to extrapolate 12-month data that we have, currently, into all low-risk patients.
Question 2 : Should this apply to all approved valves?
[Appleby] Again, no, I think it will be a little early. I don't suspect there's going to be a huge outcome difference. There will be when you look at certain subgroups, pacing rates, et cetera but, as a generalisation, I think most of us feel that the valves work, they have their individual anatomical considerations, but they work well in the bulk of the population. But really the evidence is only for two types of devices and I think, again, extrapolating it out, particularly into the younger population, would be a little bit difficult.
Question 3 : In which clinical settings would a patient not be a candidate for TAVI and how do you assess this?
[Appleby] Well, generally, when we're looking at suitability for TAVI it's actually the flip side of that, we're looking at the comorbidity or the frailty that actually makes them not suitable for surgery. So, I think, really it's appropriateness criteria. A young patient with relative low surgical risk, I feel at the moment, you'd have quite a good reason why you wouldn't consider surgery for that patient. In the older population, who are almost always comorbid, and are often frail, it's a much simpler balance. And, I think, within the UK, certainly across much of Europe and the US it's not a difficult decision either for the physician or the patient to consider TAVI as a good alternative, if not the default strategy for that patient.
Question 4 : Does durability still need to be assessed alongside factors such as coronary obstruction, longer term?
[Appleby] I think durability is certainly, something that is of concern to a lot of people. Talking about durability in a 75 or an 80-year-old patient in whom, ultimately, if you do have valve dysfunction we can redo TAVI valve-in-valve, is not a huge issue. But if you're talking about putting a TAVI, current TAVI device in a 40-year-old we really don't have any data, beyond about 10 years for those patients simply because TAVI hasn't existed that long. So, certainly, our surgeons are very exercised about durability. There are reasons to think that ... There are reasons to consider that the TAVI durability might actually not be inferior to surgical valves, bioprosthetic valves, in terms of we tend to get a larger orifice area, and certainly post-procedurally within the short to medium term follow-up we get lower gradients across that valve compared to a surgical bioprosthetic valve. So, there are reasons to think durability isn't going to be the huge issue we think it might be. But it's still early to say based on 12 month data that we have currently available. And you'll know that in the UK, Dan Blackman and his group in Leeds has done some data looking at UK experience. So we have got some data on durability out to 10 years. But, of course, these are fairly small numbers of patients. But, you know, that will evolve over time. And, ultimately, if you need to redo a valve, a redo valve-in-valve, still you could argue there's a lot less stress for the patient in terms of the insult than redo surgery. So, ultimately, although it certainly is a concern it may not transpire to be the big issue we think it is.