Shelley Wood

May 20, 2014

PARIS, FRANCE — Early results from the first 150 patients treated with the SAPIEN3 transcatheter aortic valve (Edwards Lifesciences), including a subset of intermediate-risk patients, suggest the latest iteration of the Sapien is associated with very low rates of 30-day mortality and stroke. The device, which has a novel cuff to improve the stent seal, also had some of the lowest rates of paravalvular leak yet reported with a transcatheter valve, lead investigator Dr John Webb (St Paul's Hospital, Vancouver, BC) said here in one of the first hot-line sessions of EuroPCR 2014 .

In fact, "paravalvular leak rates were so low, people began oversizing the valves less and less," Webb said in a morning press conference. Less oversizing may translate into a lower risk of annular rupture down the road, although this remains to be proven, he cautioned.

The Sapien 3 boasts a range of design updates that Webb believes make it well suited to a lower-risk group of patients. First and foremost, the valve has an external fabric cuff, which helps seal any gaps between the device and the native valve annulus. It's also lower profile, allowing delivery via a 14-French expandable sheath for transfemoral delivery and an 18-French sheath for transapical delivery.

Webb also highlighted an improved repositioning capability that allows more nuanced placement of the valve, plus larger cells in the top row of the stent platform, providing easier access to the left main coronary artery.

Finally, the device is available in four sizes: 20 mm, 23 mm, 26 mm, and 29 mm, although the 20 mm was not available during the SAPIEN3 study, and the 29 mm was not available for part of the study period, hence the lower numbers of implants of this size in results presented by Webb today.

High- and Intermediate-Risk Patients Treated

Dr John Webb [Source: EuroPCR]

SAPIEN3 enrolled 50 high-risk patients (STS score >8 or EuroSCORE >15) and 100 intermediate- to high-risk patients (STS >4 or EuroSCORE >10 to <15) between January and November 2013. A total of 16 sites in Canada and Europe participated in the study, with choice of transfemoral (TF) or transapical (TA) access left to the discretion of the heart team. In all, just over one-third of the patients were treated by a TA approach, but this may in part reflect the lack of availability of the largest (29-mm) and smallest (20-mm) valve sizes for much or all of the trial, Webb said. He predicts: "The ratio would be more like 85% TF and 15% TA, when all sizes are available."

At 30 days, all-cause mortality was just 5.3% overall (2.1% in TF patients and 11.1% in TA patients). Overall cardiac mortality was just 4.7%, and the stroke rate was 2.7%, with zero disabling strokes (one TF stroke was unadjudicated at the time of the presentation).

Importantly, echocardiographic measurements of paravalvular regurgitation showed no cases of severe paravalvular leak and a rate of moderate paravalvular aortic regurgitation of just 3.4%, a rate that dropped to 2.6% in the TF-treated patients.

Webb also highlighted the very high proportion of valves that were implanted at the intended location—99.3%—"due to precise Sapien 3 positioning."

Of note, however, a full 13.3% of patients required pacemaker implantation, a rate that Webb acknowledged was higher than most reported series with previous iterations of the Sapien.

"I think that can be attributed to a few things," Webb told heartwire . "For one, [it may reflect] practices in individual centers, but also this Sapien 3 valve is a little longer than Sapien XT, and initially people implanted it at the same location [as the XT]—that is, 50% or more below the plane of the annulus. It's become clear that with the longer stent, that isn't necessary, so over the course of the trial the implantation strategy changed, with people implanting it a little bit higher."

As experience grows—around 1000 Sapien-3 valves have now been implanted including the 150 in this study—the rate of pacemaker implantation is similar to what was seen with the XT, Webb added.

Moving Forward

Asked if there were any aspects of the earlier-generation Sapien that he misses, Webb said, "The answer is pretty much no."

"We have a valve that is very easy to implant, and I think that makes it less stressful for the physicians. It is much more accurate in terms of positioning, the sealing is much improved, and the need to oversize is much less. . . . I think there are certain circumstances where you might not want a slightly longer valve, for example mitral–valve-in-valve implants, but this is a very small market right now."

Other than that, Webb said, "I think this is going to be the valve of preference."

Following his presentation, an expert panel queried Webb on why he thought the stroke rate was so much lower than in earlier series. Web credited the improved navigability of the delivery catheter, improved valve positioning, and the smaller sheath size. As well, postdilatation was "very infrequent" in the study, at 3.3%.

He was also questioned on what he agreed was a "higher-than-expected" pacemaker rate but predicted that as people learn to implant the device slightly higher than they are accustomed to implanting the Sapien XT, the pacemaker rate will decline.

"I don't think there's much to this, but we'll need a bit more data," he said.

Webb disclosed being a consultant for Edwards.

 

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