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The TriGuard 3 cerebral protection device received no shining endorsement for approval from , who instead highlighted all the ways that the safety and efficacy data consistently pointed in the wrong direction.

The Circulatory System Devices Panel of the Medical Devices Advisory Committee did not say that the TriGuard 3 was equivalent to Boston Scientific's Sentinel -- the predicate device in Keystone Heart's 510(k) premarket submission -- based on the small, troubled REFLECT trial that had enrollment suspended twice for data integrity concerns and patient safety.

TriGuard 3 ultimately failed to meet stroke prevention and other effectiveness performance criteria in REFLECT, with efficacy outcomes actually favoring the control group without reaching significance.

Although TriGuard 3 did match the historical safety goal in that trial, it trended toward worse performance against unprotected controls in terms of stroke (11.2% vs 5.3%) and death (3.4% vs 1.8%) at 30 days after transcatheter aortic valve replacement (TAVR).

For comparison, the Sentinel had been associated with stroke and death rates of 5.6% and 1.3%, respectively, in the SENTINEL study.

Like TriGuard 3, the predicate itself has not shown effectiveness in preventing strokes during TAVR.

"This is déjà vu all over again," said panelist George Vetrovec, MD, of VCU Health in Richmond, Virginia, who recalled his participation in the 2017 FDA advisory committee discussion weighing approval for Sentinel against its unproven efficacy.

However, a major difference between then and now is that Sentinel had been perceived as having little harm before it was approved.

The Sentinel system offers particle capture and removal from two out of three cerebral vessels during TAVR. It received FDA de novo classification in 2017, setting the stage as a predicate device for future devices in cerebral protection, and is currently the only such device on the market.

TriGuard 3 is now proposed as a TAVR accessory designed to protect all three cerebral branches of the aortic arch -- the brachiocephalic, left common carotid, and left subclavian arteries -- by deflecting embolic debris downstream, away from the cerebral circulation.

The data "in no way" support an indication for cerebral protection, said committee member Keith Allen, MD, of St. Luke's Hospital of Kansas City, Missouri.

"Neither MRI nor clinical data support that statement," agreed fellow panelist Joaquin Cigarroa, MD, of Oregon Health & Science University in Portland.

Deflection per se by the TriGuard is also questionable: debris has been seen to be lodged on the device's surface. Additionally, fewer than 60% of TriGuard 3 recipients showed three-vessel coverage during at least two out of three procedural time points (i.e., pre-, during, and post-TAVR) in REFLECT.

To improve coverage, Keystone Heart recently gave the TriGuard a new crimper, boasting correct orientation and complete cerebral coverage in all patients and no strokes in observational data spanning 50 consecutive cases at a single Dutch center.

Unlike the Sentinel, TriGuard 3 has no vessel size limitations and does not require manipulation of cerebral vessels during placement. It also has the purported advantage of sharing the same femoral artery access point as a pigtail catheter for TAVR, so a third access site is not necessary.

There was no panel vote on approval during this FDA advisory committee meeting.

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