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A cerebral protection device for transcatheter aortic valve replacement (TAVR, also known as TAVI) reduced brain injury but did not improve clinical outcomes, the CLEAN-TAVI trial showed.

Diffusion-weighted MRI showed (median 4 versus 10, P<0.001) within 2 days of TAVR for potentially protected regions of the brain than seen among patients for which the Claret Montage Dual Filter System was not used. The device's two filters cover both carotid arteries and the right vertebral artery but not the left one.

The device also reduced the median volume of new lesions (242 versus 527 mm³ at 2 days, P=0.001), , of University of Leipzig in Germany, and colleagues reported online in the Journal of the American Medical Association.

The difference persisted at 5 days, with reductions observed in lesions formed (3 versus 7, P=0.003) and lesion volume (101 mm³ versus 292 mm³, P=0.002).

Yet even with these perceived benefits of the protection devices, "TAVI was associated with diffusion-weighted MRI-positive brain lesions, indicative of ischemic brain injury in almost every patient," the authors wrote.

What's more, the same number of protected and unprotected patients showed symptoms of minor stroke at 2 and 7 days. There were no cases of transient ischemic attacks.

The researchers suggested that "larger studies are needed to assess the effect of cerebral protection device use on neurological and cognitive function after TAVI and to devise methods that will provide more complete coverage of the brain to prevent new lesions."

Importantly, "device refinement, enabling complete cerebral protection, is required," they added.

Nevertheless, "the findings represent a compelling and encouraging start," , of the Hospital of the University of Pennsylvania in Philadelphia, and , of The Heart Hospital Baylor Plano, Texas, commented in an .

They called embolic protection and deflection devices "a promising adjunct to improve the safety of TAVI," albeit "whether that reduction translates to a meaningful improvement in clinical outcomes will require more study."

Linke and colleagues noted that several cerebral protection devices are available in Europe, though conflicting data within the literature make comparisons difficult.

On that end, "multiple additional industry-sponsored trials of embolic protection devices for patients undergoing TAVI are under way," Messé and Mack noted.

The single-center CLEAN-TAVI trial randomized 100 patients to TAVR with (n=50) or without a filter (n=50). All were implanted with the CoreValve self-expanding bioprosthetic valve. Patients as well as nurses and physicians involved in neurological and neurocognitive testing were blinded to assignment.

Placing the filter was associated with an 18-minute increase in procedural time on average, excluding complex anatomical cases.

Complication rates were similar between patients: Life-threatening hemorrhages occurred for one patient in each group. For major vascular complications, the distribution was five among the filtered and six for the unprotected groups. For acute kidney injury, it was one and five, respectively.

Three patients in the filter group had a thoracotomy, one case because of wire perforation of the left ventricle and two others because of an inability to release the CoreValve from the delivery catheter.

With experienced operators performing TAVR at the single center for the trial, Linke's group acknowledged limitations to the generalizability of their findings. They also noted the lack of longer term neurological assessment.

"Additional studies are needed to determine the long-term implications of clinically silent cerebral infarcts detected on MRI," the editorialists added.

"When identified in the general population, clinically silent cerebral infarcts have been associated with progressive dementia, future stroke, and increased mortality. However, it remains unclear whether clinically silent infarcts that are acquired during a cardiovascular intervention have similar long-term adverse neurological consequences."

"Embolic protection may not be feasible for every type of procedure, and other strategies for neuroprotection such as prophylactic medications, preconditioning, or selective brain cooling could have even broader implications and should be studied," Messé and Mack concluded.