TAVR Debris Captured by Sentinel Embolic Protection Differs by Valve Type

Tissue particles captured by the Sentinel filter during TAVR vary according to what valve is being implanted, according to a new analysis. There appear to be differences in the size and number of captured tissue particles, researchers found, with the largest particles observed among patients treated with balloon-expandable devices. That said, Sentinel captured debris in nearly all cases.

Last year, the US Food and Drug Administration approved the Sentinel device (Boston Scientific) for use during TAVR despite the SENTINEL trial missing its primary efficacy endpoint of significant reductions in new brain lesion volume on MRI. Cerebral protection for TAVR patients also has been a controversial topic given that use of these expensive filters is not always reimbursed.

Data presented last week at the European Society of Cardiology (ESC) Congress 2018 by Julia Seeger, MD (University of Ulm, Germany), and now published in the September 10, 2018, issue of JACC: Cardiovascular Interventions, give more detailed look at embolic protection.

After completing histopathology and histomorphometry analyses on the filters of 100 consecutive patients who underwent TAVR at their institution, Seeger and colleagues found debris in 96% of the proximal filters and 97% of the distal filters. The type of debris did not differ among the three TAVR valves used—the balloon-expandable Sapien 3 (n = 42; Edwards Lifesciences), the self-expanding Evolut R (n = 35; Medtronic), and the mechanically implanted Lotus (n = 23; Boston Scientific)—but there were more patients with large debris ≥ 1,000 µm in the Sapien 3 arm. Additionally, patients treated with the Lotus valve had fewer particles in their proximal filters (mean 89.8) compared with those implanted with Evolut R (mean 187.3) and Sapien 3 (mean 172.3; P = 0.035).

Barriers to Selective Use

Commenting to TCTMD, Howard Herrmann, MD (Penn Heart and Vascular Center, Philadelphia, PA), who was not involved with the study, said that the main take-home message is that “something was seen in the great majority of filters from everybody.” Due to the study’s size and its observational nature with missing data points, he said, it’s premature to draw any conclusions about whether to guide cerebral protection based on the type of TAVR valve used, however.

This study “reinforces the concept and conclusion from the SENTINEL trial and from other registries . . . that demonstrated that in most patients filters are capturing debris and that most of us would rather see the debris in filters than in our patients' brains,” Herrmann observed. “It doesn’t change the fact that the trial was unable to prove [a reduction in] stroke at 30 days and that has left clinicians a little bit in the middle between deciding whether the benefit is truly in capturing debris or in preventing strokes and is it worth the cost of the device.”

The problem, Seeger said in a panel discussion following her presentation, is that there are no currently known predictors of which TAVR patients are at a higher risk for stroke. “I can’t tell you in which patients you should use [embolic protection] and in which patients you shouldn’t use it,” she observed.

At her center, Seeger told ESC attendees, all patients receive predilatation, so that did not play a role in the results of the study. She acknowledged, however, that this parameter could affect the amount of debris captured—and hence, potentially stroke risk—in patients treated at other institutions.

Herrmann said he would like to be able to “selectively use this and future devices for embolic protection in those patients who are at most risk for strokes.” But given the current inability to do so, using the Sentinel system tends to be an “all-or-none kind of phenomenon” at each institution, he added. Herrmann said he convinced the administration at his hospital to “utilize Sentinel in every patient with the appropriate anatomy,” but acknowledged that this might not be an option for other centers.

“It is very reasonable to use it in everybody, but I encourage people to do what they feel comfortable with for their patients and in their reading of the literature,” he added.

‘Cheaper, Simpler’ Protection Options Needed

In an accompanying editorial, Didier Tchetche, MD, and Chiara de Biase, MD (Clinique Pasteur, Toulouse, France), write that “this study could be the last piece of the equation, as it confirms the systematic embolization of various types and sizes of debris when TAVR is performed with any kind of transcatheter heart valve.”

While larger studies are needed to further validate embolic protection in general, the editorialists say that “once we see what is captured by the Sentinel cerebral protection device, given the immediate and long-term consequences of disabling or covert stroke, it becomes intuitive that in every patient, the brain should be protected during TAVR. Even if the consequences of cerebral emboli are not immediately apparent, it remains important to limit the occurrence of periprocedural events as much as possible.”

With the seemingly inevitable expansion of TAVR to lower-risk patients with longer life expectancy, “stroke and its consequences should be prevented as much as possible,” Tchetche and de Biase conclude. “Currently, the extra cost incurred by cerebral protection device use partly prevents their wider adoption. A first step could be to identify the patients at higher risk for stroke for systematic use before broader implementation. It is probably time to update our practice and protect the brains of our TAVR patients, independent of the types of transcatheter heart valves we use for the procedure.”

In agreement, Herrmann said it is not clear yet as to how one would “utilize embolic protection based on the TAVR valve one is using.” But more focus should be placed on finding “cheaper, simpler, and maybe more effective embolic protection devices,” he stressed, calling for “more guidance from better studies on which patients are at most risk and highest risk of stroke, so that one can optimize the use of the device in those who are most likely to benefit from its use. That would be a cost-effective approach.”