Single-Center Study Compares TAVR Devices in Mixed Aortic Stenosis

BARCELONA, Spain—In patients with mixed aortic stenosis, transcatheter aortic valve replacement with CoreValve produces less favorable results compared with Sapien, researchers reported in an oral abstract session on August 31, 2014, at the European Society of Cardiology Congress. 

But session co-moderator Roxana Mehran, MD, of Mount Sinai Hospital (New York, NY), raised doubts over whether the nonrandomized, single-center study might paint a misleading picture by not accounting for how operators chose between devices when treating each patient.

Methods
Gennario Giustino, MD, of San Raffaele Hospital (Milan, Italy), shared his center’s experience treating 177 patients with mixed stenosis (at least moderate aortic stenosis plus moderate or severe aortic regurgitation) between November 2007 and September 2013. Mixed stenosis was not uncommon at the center, representing 37.6% of the 472 TAVR cases with ECG data available at baseline. 
Excluding patients treated via the transapical approach, the final study population consisted of 142 patients who received either CoreValve (Medtronic; Minneapolis, MN; n = 59) or Sapien (Edwards Lifesciences; Irvine, CA; n = 83).


Patient characteristics did not differ by the type of device used. However, ECG showed a trend toward larger aortic annulus size for CoreValve compared with Sapien (24.4 ± 2.2 mm vs 23.6 ± 2.1 mm; P = .057), accompanied by larger valve size. CoreValve procedures also involved more post-dilatation compared with Sapien (43.1% vs 16.9%; P < .001), a difference that Dr. Giustino credited to more predilatation in the latter group. 

At 30 days, the 2 devices demonstrated similar rates of all-cause mortality, cardiovascular mortality, and device success but CoreValve use carried higher rates of valve embolization, need for a second valve, permanent pacemaker, and moderate/severe periprosthetic aortic regurgitation (table 1).

Table 1. Outcomes at 30 Days

 

CoreValve

(n = 59)

Sapien

(n = 83)

P Value

All-Cause Mortality

5.2%

2.4%

.391

Cardiovascular Mortality

3.4%

2.4%

.724

Device Success

58.6%

67.5%

.282

Valve Embolization

7.5%

0

.013

Need for Second Valve

9.4%

0

.005

Permanent Pacemaker

28.8%

9.8%

.010

Moderate/Severe Periprosthetic AR

12.1%

0

.001

Abbreviation: AR, aortic regurgitation. 

Both mortality measures remained equivalent between the 2 device types at 1 year. At 2 years, however, CoreValve use was associated with greater all-cause (29.3% vs 14.6%; P = .035) and cardiovascular mortality (21.1% vs 4.9%; P = .001) than Sapien.

Additional analyses showed that “Sapien’s performance is similar in patients with mixed and pure aortic stenosis, while Medtronic CoreValve performed better in patients with pure aortic stenosis as compared to [mixed] stenosis,” Dr. Giustino noted. 

Apples to Oranges?

Following the presentation, Dr. Mehran zeroed in on potential confounding. “Certainly a retrospective analysis of this sort really begs the question of how you chose one valve over another,” she said. 

CoreValve-treated patients had larger aortic valve diameters and aortas; this makes sense, Dr. Mehran continued, but may mean that the group “could have been exposed to a higher volume load and have very, very different outcomes, as you saw. How do you correct for something like that? It’s extremely difficult to do without randomization,” she stressed.

Dr. Giustino acknowledged anatomic differences between the 2 groups. 

An audience member further commented on the rarity in the study of 31-mm CoreValve devices, which came to market after the smaller sizes. “That sort of suggests that the CoreValves were implanted at an earlier point in your experience than the Sapiens,” he said, raising the possibility of a learning curve. Dr. Giustino agreed this was the case.

 


Source:
Giustino G. Self-expandable versus balloon-expandable devices in patients with mixed aortic valve stenosis undergoing transcatheter aortic valve implantation: results from a single-center registry. Presented at: European Society of Cardiology Congress; August 31, 2014; Barcelona, Spain
.

 

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Disclosures
  • Dr. Giustino reports no relevant conflicts of interest.

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