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CHICAGO -- The question of who should get embolic filter-protected transcatheter aortic valve replacement (TAVR) cannot be resolved unless device prices go down or a definitive trial shows efficacy, a panel argued here.

So far there have been only favorable signals for efficacy of embolic protection in this setting: Imaging data has shown smaller brain lesions and MRI-visible strokes after protected TAVR. And histopathological evidence that 99% of Sentinel filters captured debris was cited again and again during the session at the annual by the Cardiovascular Research Foundation.

"We want to prevent what is unavoidable. And what is unavoidable is that debris will embolize in the brain," said Nicolas Van Mieghem, MD, PhD, of the Thorax Center at Erasmus Medical Center in Rotterdam. Therefore, all patients should be protected as a safety precaution during TAVR, he argued at the session, adding that he personally uses these devices in 80% of cases (opting out only when there is unfavorable anatomy or calcification).

Such a seat-belt approach would mean employing cerebral embolic protection every time TAVR is performed in the absence of a model to predict the people who would actually benefit from it.

But that's an imperfect metaphor, according to fellow panelist David Rizik, MD, of HonorHealth Medical Center in Scottsdale, Arizona. Would we use a seat belt if it cost tens of thousands of dollars each time? "I suspect we would use another mode of transportation," he said.

At the heart of the uncertainty over whether to use protection routinely is the lack of strong evidence that sequestering embolic materials dislodged during TAVR actually leads to a lower risk of hard events, like clinically-relevant stroke and death. After all, the significance of reducing MRI defects that would have gone unnoticed by the patient is unclear.

Using filters just for the sake of getting rid of particles is "an emotional, not evidence-based argument. It's just 'Yuck! I don't want that in my head,'" commented Jeffrey Moses, MD, of Columbia University Medical Center/NewYork-Presbyterian Hospital in New York City.

He emphasized considering the "true number" of strokes that would occur without protection, and then only the disabling ones (or ones that patients would notice): only 0.9% in the control arm of SENTINEL, and 0.6% in PARTNER 3's TAVR arm.

The rarity of these stroke events affects cost-effectiveness calculations, which are already complicated by questions regarding the economic impact of strokes and silent cerebral emboli but are increasingly important as TAVR makes its way to lower-risk patients, according to Hemal Gada, MD, of UPMC Pinnacle in Harrisburg, Pennsylvania.

And it's not just about the tradeoffs for the patient -- also at stake is the bottom line for the institutions.

Filters are already used routinely in carotid percutaneous transluminal angioplasties, but there's something different about TAVR, suggested session co-moderator Axel Linke, MD, of University of Leipzig, Germany.

The main issue is that most TAVR programs run on thin margins, said Sammy Elmariah, MD, MPH, of Boston's Massachusetts General Hospital. Adding a roughly $3,000 device with marginal efficacy data to the equation is going to affect the bottom line.

"Certainly we have a lot of data suggesting efficacy. And if you ask the patient, they would want it. But our programs also need to survive," Elmariah said.

As for the question of how some centers can afford switching to 100% protected TAVRs, Moses answered half-jokingly for his institution: Columbia, by virtue of its patient demographics and other factors, has "the highest DRG [Diagnostic Related Group] in the world."

One consequence of the uncertainty in cerebral embolic protection's value is that some hospitals are now using it as a marketing tool to lure patients, according to Van Mieghem, who called this a "moral issue."

The panel appeared to agree unanimously on the need for a well-powered randomized trial proving that protected TAVR actually prevents hard events.

One trial to watch for is the 285-person investigating the TriGuard 3 deflection device. This study should have data available in the next 6 months, noted Tamim Nazif, MD, also from Columbia.

In any case, "you can change the equation by changing the price of the device," Moses said.

"The margins of profit should be smaller just to allow us to use this safety measure in all our patients," Van Mieghem agreed.

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