French Studies Point to Inherent Differences in TAVR Valves

Patrice Wendling

November 25, 2019

PHILADELPHIA — Propensity-matched analyses from two French TAVR registries suggest a lower mortality rate and other advantages with balloon-expandable valves over self-expanding valves.

Although transcatheter aortic valve replacement (TAVR) has demonstrated its worth against open-heart valve surgery in several patient populations, sufficiently powered randomized head-to-head data on these two competing transcatheter heart valves (THVs) are lacking.

Results from a FRANCE-TAVI analysis "suggest that the two most widely used THV designs may not achieve the same clinical outcomes," study author Eric Van Belle, MD, Institut Coeur Poumon, Université de Lille, France, said at the American Heart Association (AHA) Scientific Sessions 2019.

The FRANCE-TAVI study involved 3910 matched pairs with native aortic stenosis who underwent balloon-expandable (Sapien XT or Sapien 3 valve, Edwards Lifesciences) or self-expanding (CoreValve, Medtronic) TAVR from 2013 to 2015.

The coprimary end point of at least moderate paravalvular regurgitation (PVR) at discharge and/or in-hospital mortality was more common with a self-expanding (SE) valve than with a balloon-expandable (BE) valve (19.8% vs 11.9%; relative risk [RR], 1.68). This related to nearly twofold more PVR (15.5% vs 8.3%; RR, 1.90) and a 1.4% absolute mortality difference (5.6% vs 4.2%; RR, 1.33).

Need for a permanent pacemaker (22.3% vs 11.0%; P < .0001) and a second transcatheter heart valve (3.7% vs 1.0%; P < .0001) was more frequent with SE valves.

Patients receiving an SE valve also had higher rates of myocardial infarction (0.4% vs 0.2%; P = .02) but had a lower mean transprosthetic gradient than those receiving a BE valve (7 vs 10; P < .0001).

At 2 years, use of a self-expanding valve was associated with a higher risk for all-cause mortality (29.8% vs 26.6%; hazard ratio, 1.17; 95% CI, 1.06 - 1.28) and cardiovascular death (23.3% vs 20.9%; P = .001). This is explained by a 36% excess risk for death during the first 3 months (= .0001), with the two mortality curves remaining parallel thereafter, Van Belle said.

The findings were consistent across subgroups, although the difference in the primary composite end point was stronger for those who received transfemoral TAVR and for those treated at the end of the study in 2015.

On multivariable analysis, independent predictors of all-cause mortality were valve design and PVR severity, according to the study, simultaneously published online in Circulation.

Limitations include the use of observational data, potential unmeasured residual confounders, site-reported PVR grading and clinical events (except mortality), and a lack of newer valve designs, Van Belle said.

"The present study strongly supports conducting a randomized trial in order to compare head-to-head the most recent iterations of SE and BE THVs on all-cause mortality," he concluded.

Invited discussant Dharam Kumbhani, MD, University of Texas Southwestern Medical Center, Dallas, said that "it is hazardous to make causal inferences from observational data, and we all know this, but I cannot overemphasize this."

The study, he said, "points out, if nothing else, that perhaps there is an inherent difference between the TAVR valves. It may be incorrect to assume it is a class effect."

A second propensity-matched analysis, also published online in Circulation but not presented at AHA, used the nationwide French administrative hospital-discharge database to compare 10,459 matched pairs who underwent TAVR with the balloon-expandable Sapien 3 or self-expanding Evolut R (Medtronic) valve from 2014 to 2018.

Over a mean follow-up of 358 days, use of the BE vs the SE valve was associated with a lower yearly incidence of all-cause death (rate ratio, 0.88; corrected P = .005), cardiovascular death (rate ratio, 0.82; corrected P = .002), and rehospitalization for heart failure (rate ratio, 0.84; corrected P < .0001).

Pacemaker implantation was also lower with the balloon-expandable valve (rate ratio, 0.72; corrected < .0001), Pierre Deharo, MD, PhD, CHU Timone, Marseille, France, and colleagues report.

In an editorial accompanying the two analyses, Mohamed Abdel-Wahab, MD, and Holger Thiele, MD, both with the Heart Center Leipzig at the University of Leipzig, Germany, praised the authors for reporting what is currently the largest published dataset comparing the two valve designs. The limitations of registry-based analyses, however, are "obvious, and the findings should therefore be considered thought-provoking but by no means definite."

They note that the higher PVR rate in the self-expanding valve groups is "neither novel nor surprising," given existing evidence, and that PVR rates remain higher in current-generation SE valves, despite now being largely repositionable and generally showing improved sealing properties.

Explaining the mortality difference in both studies in favor of current and early generation BE valves "remains quite complex," Abdel-Wahab and Thiele say. Although PVR is unequivocally linked to higher short- and intermediate-term mortality, "it remains unclear if PVR is directly acting as a cause or partly acting as a marker of a higher risk subgroup."

The editorialists point out that device selection has evolved from the early days of TAVR, and that current factors include operator familiarity and specific anatomical characteristics that would affect periprocedural complications and hemodynamic function of both valve designs.

As TAVR expands to low-risk patients, "we are starting to consider valve durability, coronary access and the possibility of repeat interventions in our device selection algorithms," Abdel-Wahab and Thiele write. "While it seems obvious that a significant proportion of patients can probably be safely treated with either a BEV or a SEV, we cannot advocate that both device types are equal and can always be used interchangeably. This is surely different than the coronary stent business."

The two studies, "probably demonstrate that implantation of the wrong device in the wrong patient may negatively affect patient outcomes," the editorialists conclude. "This is a call for differential treatment, which can only be achieved with a certain volume and level of experience with the inherently different and continuously evolving TAVR device platforms."

"This is also a call for more randomized clinical evidence, particularly in anatomical situations that are believed to be equally treatable with both platforms, and with clinical endpoints relevant to the long-term expectations of a lower risk population."

FRANCE-TAVI database was funded and managed by the French Society of Cardiology and French Working Group of Interventional Cardiology. Edwards Lifesciences and Medtronic partly funded the registry, but had no role in data collection, analysis, or manuscript drafting. Van Belle, Dehara, Abdel-Wahab, and Thiele report no relevant conflicts of interest.

Circulation. Published online November 16, 2019. Abstract, Abstract, Editorial

American Heart Association (AHA) Scientific Sessions 2019; presented November 16, 2019.

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