From the Journals

Cerebral protection in TAVI cuts ischemic lesions

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Hossein G. Almassi, MD, FCCP, comments

As there was no significant difference in clinical neurological outcomes related to use of a filter device, although there was significantly fewer and smaller brain lesions in the stroke group, one is left to conclude that the majority of MRI findings after TAVI are not clinically relevant. Is the added cost of a cerebral protection device cost effective given the equivalent neurological outcomes in the both groups?


 

In patients undergoing transcatheter aortic valve implantation, use of a cerebral protection device to entrap and remove embolic debris reduced both the number and the size of ischemic brain lesions, according to a report published in JAMA.

The frequency and severity of postprocedure stroke symptoms were similar with and without the filter; however, the researchers noted that the study included only 100 patients and was not powered to assess differences in stroke rates.

Various cerebral protection devices were invented in response to the finding of a threefold increase in periprocedural stroke mortality following TAVI. Yet “clear evidence of the efficacy of any embolic protection device in TAVI is still missing,” said Stephan Haussig, MD, of the University of Leipzig (Germany) Heart Center, and his associates.

They performed a prospective randomized clinical trial at their center to assess the efficacy of the only cerebral protection device that was available when their study was designed. For the study, 100 patients with severe, symptomatic aortic stenosis were randomly assigned to undergo TAVI either with (50 patients) or without (50 patients) the use of a protective filter to capture embolic debris. The filter device was estimated to fully protect 74% of the brain and partially protect 24%, leaving only 2% unprotected.

The primary endpoint of the study was the number of ischemic brain lesions detected on diffusion-weighted MRI in the filter group, compared with the control group. This imaging was performed at baseline, 2 days after the procedure, and 7 days after the procedure.

In protected brain regions, the median number of new ischemic brain lesions was markedly lower in the filter group than in the control group (4 vs. 10) at 2 days, as well as at 7 days (3 vs. 7, respectively). In addition, the volume of new lesions in protected brain regions also was markedly lower in the filter group at 2 days (242 mm vs. 527 mm) and at 7 days (101 mm vs. 292 mm).

Similar protective effects were evident when the entire brain was evaluated. The median number of new lesions was markedly lower in the filter group than in the control group (8 vs. 16) at 2 days and at 7 days (5 vs. 10, respectively). The median lesion volume also was markedly lower in the filter group at 2 days (466 mm vs. 800 mm) and at 7 days (205 mm vs. 720 mm).

However, this protective effect didn’t translate into a substantive difference in neurologic outcomes between the two study groups, as assessed by the National Institutes of Health Stroke Scale and the modified Rankin scale. Five patients in each group developed symptoms of stroke, and all symptoms were deemed minor and nondisabling, the investigators said ( JAMA 2016;316[6]:592-601 ).

It is important to note that this study wasn’t powered to assess differences in stroke rates. Larger studies will be needed to assess the impact of protective devices on neurological and functional outcomes, Dr. Haussig and his associates wrote.

The two study groups also did not differ with regard to complications. Thirty-day mortality was 0% in the filter group and 2% in the control group, a nonsignificant difference.

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