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SAN DIEGO -- An experimental embolic protection device for transcatheter aortic valve replacement (TAVR) reduced clinically-silent embolic lesions in the brain, with possible cognitive benefits, an early phase study showed.
The TriGuard device, mesh on a nitinol frame that fits across the three arteries that feed the brain, was associated with a lower volume of new lesions compared with unprotected TAVR (73 versus 88 mm3) translating to a roughly in the intent-to-treat analysis of the DEFLECT III trial.
Action Points
- Note that this study was published as an abstract and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.
- Note that this randomized trial of a device to protect the brain from embolic debris during transcatheter aortic valve replacement demonstrated promising results in terms of volume of new lesions detected on MRI.
- Be aware that the sample size was too small to robustly assess various safety and efficacy metrics.
The proportion of people with zero new lesions on diffusion-weighted MRI after the procedure was 21.9% with the device compared with 12.5% without it in the intent-to-treat analysis, , of Yale, reported here at the American College of Cardiology meeting.
"In addition to reducing the clinical stroke rate, which is down very very low, we still need to reduce the degree of embolic debris that goes to the brain. We may not be able to detect it, but it can't be good," commented , director of interventional cardiology clinical services at Beth Israel Deaconess Medical Center in Boston.
"Certainly getting the stroke rates down is good for TAVR, but getting the brain lesions down over time is very important for patients," he said as study discussant at a press conference.
A battery of neurocognitive scores turned up better results with the embolic protection device in the trial, although Lansky cautioned that the study was not powered for formal hypothesis testing or clinical outcomes.
Scores on the Montreal Cognitive Assessment (MoCA), validated in detection of mild cognitive impairment, improved from baseline to discharge but dropped over that time in the group treated without embolic protection. The proportion with scores that were at least maintained on this test after the procedure was 73.7% with the device and 63.3% without it.
Visual learning and short-term memory on the CogState test showed the same pattern (P=0.043 and P=0.028 for time by treatment interaction).
An actual improvement is plausible, because "post-TAVR you have more blood flow to the brain because your cardiac output is better, and that can certainly have an impact on memory and brain function globally," commented , medical director of Ochsner Medical Center's heart valve program in New Orleans and chair of the ACC Interventional Council.
And "presumably the mechanism is if you are preventing a sizable proportion of patients from having any of these [embolic] 'hits' then you're going to have overtime from baseline to post-procedure have improvements certainly compared with the controls that have a higher burden of lesions," Lansky noted.
But this also may to some extent reflect a test-learning effect or statistical noise, Lansky told 榴莲视频. "We need to take this to a powered, larger-scale randomized clinical trial to establish the clinical effect."
Silent embolic events after TAVR have been associated with neurocognitive decline, dementia, and stroke in prior studies, and more than half to nearly all patients have these lesions apparent after the procedure, she pointed out.
Clinical stroke rates were similar between groups (one of 45 in the device-treated group and two of 38 in controls).
The multicenter trial randomized 83 patients undergoing TAVR, via transfemoral or transapical access, to be treated single-blind with or without TriGuard. Participants could not have stroke or transient ischemic attack in the prior 6 months, any anatomic irregularities, or other cardiac interventions in the prior 2 weeks. About one-third of patients received a CoreValve TAVR; nearly all the remainder were treated with a Sapien 3 device.
The device did extend time under fluoroscopy by nearly 10 minutes. It could be successfully deployed in 94% of patients but maintained coverage of all three vessels until final valve deployment in 87%.
While it couldn't be retrieved successfully in one of the 45 patients, it didn't interfere with TAVR in any cases.
Notably, the protection afforded to patients who got CoreValve TAVR devices appeared to be less than that with the steerable Sapien TAVR device, Lansky told attendees, noting that none of the former were free of ischemic brain lesions compared with more than half of those treated with the Sapien product.
In-hospital major adverse cardiovascular and cerebrovascular event rates were too low for comparison but clearly didn't increase risks.
Limitations, aside from the small size and early phase, included a high loss to diffusion-weighted MRI of 35% and 17% loss to neurocognitive testing for the post-procedure assessments.
The trial was designed to benchmark safety and efficacy for the pivotal REFLECT trial, which is underway.
Disclosures
Lansky disclosed CardioDX, Keystone Heart, AstraZeneca Pharmaceuticals, Daiichi Sankyo, Eli Lilly, and Merck.
Primary Source
American College of Cardiology
Source Reference: Lansky AJ, et al "First report of the DEFLECT III trial results: A prospective randomized evaluation of The TriGuardTM HDH embolic DEFLECTion device during transcatheter aortic valve replacement" ACC 2015; Abstract 404-16.