Two TAVI Devices Comparable, But Different

October 20, 2011

October 20, 2011 (London, United Kingdom) — New results are helping to inform operators about best practices for transcatheter aortic-valve implantation (TAVI), the PCR London Valves 2011 meeting heard this week. More than 40 000 TAVI procedures have now been performed worldwide, and the accumulating data are helping guide patient selection, choice of valve, and route of access, among other things, presenters said.

In a session on the latest registry data, there was general agreement that the two devices available in Europe--the Edwards Sapien valve and Medtronic's CoreValve--are broadly comparable, yet different, so that in many cases individual patient characteristics should guide the choice of valve.

However, one expert also feels that the volume of procedures performed by a center or operator should play a role in valve selection, with low-volume centers being better off using only one device, while those who perform many TAVI procedures could use both, selecting the best "fit" for a particular patient.

If you do few TAVI procedures, then you should focus on one device.

"If you do few TAVI procedures--which I would say is less than three to four a week--then you should focus on one device. But if you do a sizable number of procedures, you can focus on more than one device," said interventionalist Dr Antonio Colombo (San Raffaele Hospital, Milan).

Pressed as to which patient he would choose for which device, Colombo answered: "I have no conflicts of interest and we try to utilize the systems in a very balanced way. We prefer the CoreValve in patients with a bicuspid valve, those with a very asymmetric annulus in multislice computed tomography [CT], those in whom the vascular anatomy is tortuous--because I feel the CoreValve is a little bit more flexible--and if I want to avoid general anesthesia and they have a bad vascular anatomy I can use the CoreValve device via the subclavian route with local anesthetic."

We have enough experience with TAVI now that we have to accept that the devices are different and they do have different advantages and disadvantages.

And session panelist surgeon Dr Neil Moat (Royal Brompton and Harefield NHS Foundation Trust, UK) commented: "We have enough experience with TAVI now that we have to accept that the devices are different and they do have different advantages and disadvantages, and I think it's excellent that we are starting to discuss the type of patients that would benefit from one device or another."

Subclavian Mortality Rises at One Year in Latest UK Data

Although TAVI is still in its infancy, meeting presenters in London said it has already become the standard of care for inoperable patients with severe aortic stenosis in many countries, as well as an acceptable alternative to surgical aortic-valve replacement in selected high-risk operable patients.

First up in London, reporting the very latest data from the UK Transcatheter Aortic Valve Implantation (UK TAVI) registry, was Dr Daniel Blackman (Sussex Cardiac Centre, Brighton, UK). Just this week, earlier results from this registry, on 800 patients, were published; Blackman was able to expand on this, presenting data on 1600 patients treated until December 31, 2010, with approximately half getting the CoreValve and the remainder the Edwards Sapien device.

Blackman was also able to provide one of the first large data sets on outcome by access route, which varies depending on the valve being implanted and on the anatomy of the patient. Sapien is approved in Europe for implantation via the transfemoral and transapical approaches, whereas the CoreValve is generally inserted via the transfemoral or subclavian route. Of patients who got the CoreValve 85% to 90% received it via the transfemoral route, the remainder via subclavian access, Blackman said. For the Edwards valve, the access route was transfemoral 50% of the time and transapical the remaining 50%.

The patients selected for transapical or subclavian access (normally selected when the femoral arteries are inaccessible) were higher risk, with significantly greater EuroSCOREs, than those undergoing TAVI via the transfemoral route, he noted.

There was no difference in 30-day or 12-month mortality between the two patient groups (CoreValve and Sapien) receiving valves via the transfemoral route and no significant differences in terms of stroke, MI, or major access-site complications.

For alternative access, 30-day mortality was significantly higher for those receiving TAVI via the transapical route compared with transfemoral and subclavian. Mortality at 12 months was also higher with transapical compared with transfemoral, and at this time point, the survival for those receiving TAVI via the subclavian route had also taken a downward turn.

"While the subclavian survival tracks with the transfemoral early on, it seems to decline such that, at 12 months, there is no difference between subclavian and transapical survival," Blackman noted.

Outcomes in UK Registry With Different Valves and Different Access Routes

Outcome Edwards transfemoral, n=389 (%) CoreValve transfemoral, n=706 (%) p Edwards transapical, n=409 (%) CoreValve subclavian, n=91 (%) p
30-d mortality 4.3 5.2 NS 11.2 4.4 <0.01a
12-mo survival 84.5 80.8 0.453 74.5 75.4 <0.001b
New permanent pacemaker 6.2 21.6 <0.001 5.6 22.1 <0.001
Aortic regurgitation >2 8.4 13.4 0.015 6.4 9.5 0.34

a. For transapical when compared with the pooled femoral data

b. For nontransfemoral vs transfemoral

Pacemaker Implantation and Aortic Regurgitation Higher With Corevalve

Blackman was asked by Moat what he thought was happening with regard to the subclavian patients between 30 days and a year, with a suggestion that "perhaps we are not looking after that cohort of patients very well, in that period, sending them out and not doing very much. Could we improve or lessen that rate of attrition if we cared for these patients more aggressively over that period?"

Blackman said, "The published data from the Italian registry don't show the same pattern; they showed the Kaplan-Meir [survival curves] for the subclavian tracked the femoral, albeit in only 50 or so patients, so I don't know for sure whether it's a real phenomenon.

"Probably all of our experience in TAVI is that it can be disappointing that patients with a successful outcome from the procedure you find falling off their perches at some point up to the next 12 months," Blackman observed, although he acknowledged that this doesn't entirely explain the way the curves change in the subclavian group compared with the transapical.

In fact, the whole subject of the decline in survival between 30 days and 12 months in all TAVI recipients was a subject of much discussion at the meeting, with many stating that, going forward, it would be better to put more emphasis on 12-month death rates, rather than procedural and 30-day mortality figures, which historically have been the most often cited.

With regard to differences in adverse outcomes between the two valves, permanent pacemaker implantation rates and grade 2 or more aortic regurgitation (AR) at the end of the procedure were both significantly higher with the CoreValve device, Blackman noted. For pacemaker implantation, this was true regardless of the route of access, but for AR, the difference was significant only for transfemoral procedures, he said.

Milan Prefers Subclavian Approach to Transapical for Hard Cases

Next up was Colombo, who reported outcomes with the two TAVI devices from patients treated at a single center, in Milan, from November 2007 to July 2011, where 60% of patients (n=169) got Sapien valves, 85% of these via the transfemoral route and 13% via the transapical route. Of the 40% who got CoreValves (n=99), 76% were implanted transfemorally and the remainder via subclavian access.

Colombo explained that few procedures are performed transapically now in his center because, in cases of unfavorable anatomy for the transfemoral approach, they tend to implant a CoreValve using the subclavian approach rather than a Sapien via the transapical route.

There was no significant difference in safety and efficacy or composite Valve Academic Research Consortium (VARC) outcomes according to the valve type, with the exception of conduction disturbances, arrhythmia, and permanent pacemaker implantation, which again were significantly higher with the CoreValve device (p<0.001), Colombo noted.

He concluded that TAVI is a viable option with both valves, with them performing in "a very similar fashion," except for the "well-known" risks of conduction disturbances and pacemaker implantation with the CoreValve. These "encouraging results need to be confirmed at longer-term follow-up and to assess valve durability."

FRANCE 2: TAVI in Cath Lab Cheaper Than Aortic Valve Surgery

Finally, Dr Martine Gilard (Brest University Hospital, France) presented an update on the French registry, which she called "FRANCE 2," including over 2000 patients treated until July 2011, in which she noted there was also "no difference between the two valves," with the exception, again, of more pacemaker implantation with the CoreValve device. All patients receiving TAVI in France are enrolled in this registry, she explained, and the vast majority were implanted in the cath lab (75%) and under general anesthesia (72%).

Major Complications (30 Days)

Adverse event Global, n=2419 (%) Edwards, n=1634 (%) CoreValve, n=785 (%)
Vascular complications 10.9 10.2 10.8
New pacemaker 13.6 8.5 20
Bleeding (+tamponade) 17.4 18.1 15.7
Stroke 4.0 4.0 3.9

An economic evaluation was also performed, Gilard said, which showed no difference between costs using the two different valves when all expenditures, including hospital stay, were taken into account (mean cost €31 973). This was cheaper than the cost of performing aortic-valve-replacement surgery, she noted (mean €40 417), although she pointed out that the majority of TAVI procedures are performed in the cath lab in France, which is cheaper than using a hybrid lab or operating room.

Blackman is a proctor for Medtronic. Colombo has no conflicts of interest.

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