Docs Debate Valve Choice as Number of TAVI Devices Set to Mushroom

October 10, 2012

October 5, 2012 (London, United Kingdom) — As many as a dozen new transcatheter valves are poised to enter the market soon--at least outside of the US--so there was much discussion at the PCR London Valves 2012 meeting this week as to how practitioners would choose which new devices to adopt for transcatheter aortic-valve implantation (TAVI).

"At this point, we are only beginning this era, and choice will largely be based on additional advantageous features of the second-generation devices as compared with the first-generation valves," Dr Nicolo Piazza (German Heart Center, Munich) told a session on how to decide valve size and type.

"So far it was pretty easy, we had a balloon expandable valve (Sapien, Edwards Lifesciences) and a self-expanding one (CoreValve, Medtronic)," Dr Stephan Windecker (University of Bern, Switzerland), chair of the session, commented. But new criteria will need to be developed for choosing additional valves, he explained.

Currently, some centers have adopted only one of the two established valves, while others choose according to the anatomy of the patient, the optimal access route for that person, and the annulus size of valve required. Piazza said he believes small-volume centers (performing 30 to 50 TAVIs per year) likely need to employ only a couple of valves, as this will cover 90% of the patients encountered. But a higher-volume center could perhaps have a bigger pool to choose from, he noted.

One of the upsides of the growth in the market, say doctors, is that the availability of more devices will ultimately drive down the cost; a transcatheter valve alone, without the associated costs of the procedure, can typically cost up to $30 000.

Newer TAVI Devices Do Not Represent a Quantum Leap But Will Be Used

At this point, we are only beginning this era, and choice will largely be based on additional advantageous features of the second-generation devices as compared with the first-generation valves.

"The two first-generation valves, the Sapien and CoreValve, have been really very successful--much better than anyone would have thought--so the bar has been set very high," surgeon Dr Neil Moat (Royal Brompton and Harefield NHS Foundation Trust, UK) commented to heartwire .

And while the newer devices do appear to offer some advantages over the older ones, "the improvements that we are looking at are subtle. I don't think there is a device out there that you look at and think, 'That is a quantum leap forward,' " he observed. "Let's compare it with PCI. It's not the stepwise improvement that you got from balloon angioplasty to stents or from stents to drug-eluting stents--they were big, conceptual, dramatic changes. In TAVI, I don’t see anything like that at the moment."

I don't think there is a [new] device out there that you look at and think, 'That is a quantum leap forward.'

Moat believes it will be challenging for the newer valves to carve a niche. "A new valve is going to have to show something that is better than what we already have; otherwise, why would anybody use them? The biggest hope is for less paravalvular aortic regurgitation."

It's not just new valves that are entering the market either--adjustments are being made all the time to the delivery systems for the valves, "which offer different things in terms of accuracy of positioning and retrievability," says Moat. And other allied products, such as cerebral embolic-protection devices, are also being investigated.

New Transcatheter Heart Valves Nearing or on the Market

Company

Valve name, sizes, and delivery route, where known

Status

Boston Scientific

Lotus Valve System

Transfemoral route

Being evaluated in REPRISE clinical program

Direct Flow Medical Inc

Direct Flow Medical valve

Transfemoral route

Under investigation in DISCOVER trial with planned enrollment of 100 patients

Edwards Lifesciences

Sapien XT

23-mm, 26-mm, and 29-mm

Transfemoral and transapical routes

SOURCE XT registry

Edwards Lifesciences

Sapien 3

26 mm with 20 mm, 23 mm, and 29 mm

Anticipated transfemoral route

CE Mark trial has begun.

Edwards Lifesciences

Centera

23-mm, 26-mm, and possibly 29-mm

Transfemoral or subclavian routes

First in-human feasibility study performed in 10 patients. CE Mark trial expected to begin late 2012

JenaValve

JenaValve device

23 mm, 25 mm, and 27 mm

Transapical system

CE Mark September 2011. Pivotal CE Mark study in 67 patients published

JenaValve

JenaValve device

Transfemoral route

Not known

Medtronic

Engager (Ventnor) valve

23 mm and 26 mm

Transapical only

First-in-human and feasibility trials completed. Data on 60 patients out of 150 (mid-term analysis) from CE Mark study will be presented at EACTS meeting

Medtronic

CoreValve Evolut

23 mm

Transfemoral route

All patients implanted with Evolut will be enrolled in a registry

St Jude Medical

Portico

23 mm

Transfemoral route

CE Mark study ongoing with 45 of 50 patients enrolled. US pivotal trial expected to start 2013

Symetis

Acurate

Transapical route

CE Mark approved in September 2011 based on two trials. Postmarket registry ongoing.

Symetis

Acurate

Transfemoral route

First 20 patients study completed. Further trial in 150 patients planned. CE Mark submission expected in 2013

Decision on Whether and When to Use New Devices Is Tricky

It is tricky to decide whether or when to begin using newer devices, Moat observes. "There's a clear process of early evaluation, safety, CE Mark, in Europe. But all the CE Mark does is say the valve does what it says on the tin. It will work as a valve. It doesn’t give you any evidence as to clinical effectiveness. So then you need to do some post–CE Mark studies to look at clinical effectiveness and cost-effectiveness.

All the CE Mark does is say the valve does what it says on the tin. It will work as a valve. It doesn’t give you any evidence as to clinical effectiveness.

"As a clinician, ethically it's quite challenging to decide whether to try a new valve. If I see that there is something in the design of the device that offers a theoretical advantage, I think I have the ethical right to try it, but patient consent is very important, it's imperative that they are aware this is a new device," he says.

Currently, a large proportion of the testing of newer devices is performed in Germany, said Moat, and the latest statistics from the GARY registry bear this out. When considering the transapical route only, while the lion's share of procedures are still done with an Edwards valve (87.5%), 4.5% are now being performed using the new JenaValve system, and a further 4.5% with the novel Symetis valve, with "others" making up 3.6% of procedures.

Windecker told heartwire he is still pondering a number of questions, such as what will be the minimum data set he will require before he feels comfortable employing a new valve in his own lab and what will be the maximum number of different valves he will eventually offer.

"It's certainly something that needs a lot of thought and discussion, but in a nutshell, we would need short-term evaluation in terms of device performance and safety and long-term performance in terms of valve durability," he observed.

Piazza said: "With respect to how much data I'd like to see in order to adopt a new transcatheter-valve technology, it all depends on the new features that the valve is bringing us. We will all have to grow up with the technology as it matures."

Access to New Devices Differs Across the Pond

While doctors in Europe and elsewhere are grappling with if, when, and how to incorporate new TAVI devices into their practice, many physicians in the US are feeling frustrated that they can't yet get their hands on these new valves and other technologies, other than by participating in a clinical trial.

Regulations in the US stipulate that pivotal trials must be performed with TAVI devices before they are approved, and the Edwards Sapien was the first such device to be cleared for marketing there, just at the end of last year. A pivotal trial of the CoreValve device is still under way in the US. "That's why we are using valves in the US that aren't being used in Europe anymore," mused Dr David J Cohen (Saint Luke's Mid America Heart Institute, Kansas City, MO), while giving a talk at the meeting on reimbursement for TAVI devices.

While US pivotal trials of some of the newer valves are planned--for example, with the St Jude Medical Portico valve--these large trials may be out of the financial reach of some of the smaller companies developing new valves and other technologies.

Dr Danny Dvir (Washington Hospital Center, DC and Rabin Medical Center, Israel) told heartwire : "It's very frustrating for US operators not to have access to the latest technology--to see it at conferences but not be able to use it. And the most frustrating thing is, these are patients' lives. You have old ladies and you have to put a big sheath in their groin; this is the only option you have for them. It's troubling when you know that, in another country, that patient would get a smaller sheath. And it directly translates into complications--a big sheath equals more vascular complications."

Dr Raj Makkar (Cedars-Sinai Heart Institute, Los Angeles, CA), agrees this can be exasperating: "It is painful at times, but that's the way things work in America," he told the meeting. "Unless things change dramatically, which I don't expect they will anytime soon, this is the way we will have to go."

There is some hope, however, in the form of subsets of big trials that do allow some access to newer devices "so everything will get in eventually but it will take a lot of time," said Dvir. For example, in PARTNER IIa, the trial of the Sapien valve in intermediate-risk patients, one subset is comparing Sapien with the newer Sapien XT version of the valve.

First-in-Human Data on New Symetis Transfemoral Valve

Also at the PCR London Valves meeting, Dr Helge Möllmann (Kerckhoff-Klinik, Bad Nauheim, Germany) presented some first-in-human data on a new transcatheter valve from Symetis, delivered via the transfemoral route into 20 patients who were, on average, 85 years old with a EuroSCORE of 27, in NYHA class 3 or 4, and 85% female.

Of the 20 devices, 19 were successfully implanted, said Möllmann, with one patient requiring a valve-in-valve procedure as the first valve was initially placed too low. "Rates of new pacemaker [implantation] were low for a [transfemoral] system, at 10%," he noted.

At 30 days, there were no deaths or MIs, but one stroke and one reintervention with conversion to surgical aortic-valve replacement seven days after the initial TAVI. "Efficacy data show very nice results with a mean gradient of only 7 mm Hg and only one patient with +2 paravalvular leakage. NYHA class improved from 100% class 3 or 4 to nearly 95% class 1 and 2," he noted.

"The [first-in-human] trial with the new Symetis transfemoral valve has been successfully completed with four operators at four centers--two in Brazil and two in Germany--who implanted 20 valves, from 21 mm to 27 mm. The feasibility was nicely proved with very good results at 30 days," he concluded.

Möllmann has received speaker honoraria from Symetis.

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