Major trial finds jury still out on whether CEP devices add value to TAVR

The incidence of periprocedural stroke associated with transcatheter aortic valve replacement (TAVR) is similar whether or not a cerebral embolic protection (CEP) device is used to capture and remove embolic debris, a major international trial shows.

The international RCT across 51 centres in North America, Europe and Australia randomised 3,000 patients with aortic stenosis to TAVR with CEP or TAVR alone.

All investigators were experienced in using the CEP device, the Sentinel Cerebral Protection System, and the device was successfully deployed in 94.4% of attempts.

The study found its primary outcome – clinical stroke within 72 hours after TAVR or before discharge – was lower than expected and did not differ significantly between the CEP and the control groups (2.3% vs. 2.9%; difference, −0.6 percentage points; 95% confidence interval [CI], −1.7 to 0.5; P=0.30).

“…however, as reflected by the 95% confidence interval, the results may not rule out a benefit of CEP during TAVR,” it said.

The study, published in the NEJM [link here], found most stroke events occurred within 24 hours after the TAVR procedure.

“Disabling stroke occurred in 0.5% of the patients (8 of 1501) in the CEP group and in 1.3% of patients (20 of 1499) in the control group (difference, −0.8 percentage points; 95% CI, −1.5 to −0.1).”

Within the disabling stroke group, ischaemic strokes were lower with the CEP device than in the control group (0.4% v 1.1%).

Non-disabling strokes were reported in 1.5% of the CEP group and 1.7% of the controls.

There were no substantial differences between the CEP group and the control group with respect to death from any cause; a composite end point of stroke, transient ischaemic attack, or delirium; or acute kidney injury.

“Among the patients with stroke, there was no apparent difference between the CEP group and the control group with respect to all-cause mortality within 72 hours after TAVR or before discharge (2.9% [1 of 34] vs. 4.7% [2 of 43]) or at the 30-day follow-up (11.8% [4 of 34] vs. 11.6% [5 of 43]).”

The study found female sex was associated with stroke (odds ratio, 1.93), and use of a balloon-expandable valve was inversely associated with stroke (odds ratio, 0.46).

“A residual stroke risk of 2.3% remained in the CEP group, which may have been affected by the inability of the CEP device studied here to filter all small debris, owing to either malapposition or embolic material smaller than the pore size and the fact that the CEP device used in the current trial does not cover the left vertebral artery, thereby limiting complete cerebral coverage,” the study said.

The investigators, including cardiologist Associate Professor Robert Gooley from Monash Health, calculated that the number of patients needed to treat to prevent one additional disabling stroke would be 125.

“Although this trial was not powered to assess disabling stroke and a residual risk of stroke was observed with the use of the CEP device, given patient concerns over disabling stroke, the observed difference in the incidence of this outcome between the CEP group and the control group may be considered to be important by patients and caregivers.”

“The ultimate decision regarding the use of a CEP device during TAVR should be based on careful discussions between caregivers and patients about the risks and benefits and should incorporate personalised interpretation of the data from this and other trials of CEP, as well as other factors, including device cost.”

An editorial in the journal [link here] said the negative results of the study were in part due to the low incidence of stroke events in the control group.

“…stroke frequency without CEP is low in contemporary practice as compared with the early experience with TAVR and is likely due to operator experience, technical refinements to procedural equipment, and the use of TAVR in healthier patients.”

“The lower number of disabling strokes in the CEP group than in the control group, while small in magnitude and not definitive, is an important observation that is physiologically in accordance with the expectation that embolic protection devices are better at blocking large rather than small emboli.”

They noted that the US FDA approved the Sentinel CEP device on the basis of data showing a high rate of capture of debris but not a reduction in the risk of clinical stroke.

“As a whole, this trial strikes a serious blow to the hope that this first CEP device would have a definitive effect in the prevention of TAVR-related strokes.”

“The safety of the device and its possible effect on disabling strokes provide a ray of hope, but the concern persists that CEP, approved and marketed on the basis of surrogate outcomes, may not actually provide a clear and incontestable clinical benefit.”

The PROTECTED TAVR study was supported by Boston Scientific.

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