Deflection Device Reduces Volume, Not Number, of Cerebral Lesions During TAVR

PARIS, France—While failing to reduce the number of new cerebral lesions after transcatheter aortic valve replacement (TAVR), a unique embolic deflection device does reduce the volume of such lesions by more than half compared with historical controls, according to early results presented Wednesday, May 22 at EuroPCR 2013.

The TriGuard embolic deflection device (Keystone Heart, Caesarea Business Park, Israel) is a nitinol mesh filter with a pore size of 250 µm designed to deflect cerebral emboli while allowing maximal blood flow during TAVR procedures. Stabilizers maintain the filter’s positioning across all 3 cerebral vessels. The device is delivered via femoral access using a 9-Fr sheath.

For the DEFLECT I trial, researchers led by Michael J. Mullen, MD, of University College Hospital (London, United Kingdom), tested the device in 28 TAVR patients, most of whom were female (75%) and NYHA Class III (63%). Almost two-thirds (64%) received CoreValve (Medtronic, Minneapolis, MN), while the rest received the Sapien valve (Edwards Lifesciences, Irvine, CA).

Prior to TAVR, the TriGuard device was 100% successful in accessing the aortic arch and achieving proper positioning in the arch. Positioning success was 96% post TAVR and 79% after TAVR catheter and guidewire removal. The deflection device was 93% successful in covering all 3 cerebral vessels prior to TAVR. This rate fell to 82% after TAVR and 68% after TAVR removal.

The TriGuard device was stabilized and anchored in the innominate artery in 86% of cases before TAVR, 82% of cases after TAVR, and 64% after TAVR removal. All TriGuard devices were retrieved intact after TAVR removal.

No Device Related Events

There were no TriGuard-related adverse events in-hospital or by 30 days. The rate of MACCE related to the TAVR procedure itself was 7.1% in-hospital and 10.7% at 30 days. TAVR-related major stroke disability was 7.1% in-hospital and at 30 days. Other 30-day MACCE events included death (3.6%), major access complication (3.6%), urgent cardiovascular surgery (3.6%), and acute kidney injury stage 3 (3.6%). There were 2 disabling strokes that occurred 1 day after TAVR that were not related to TriGuard.

Unfortunately, on diffusion-weighted MRI (DW-MRI), TriGuard failed to reduce the number of new lesions compared with historical controls. However, the average new lesion volume was 65% less with TriGuard, while total new lesion volume was 57% reduced (table 1).

Table 1. DW-MRI Results: Lesion Number and Volume

^a Kahlert 2010, Ghanem 2011, Astarci 2011, Stolz 2004, Rodés Cabau 2011.

Dr. Mullen noted TriGuard’s positive safety profile and good performance in covering all 3 cerebral vessels in the majority of cases until completion of TAVR deployment. But the paradox of reducing new lesion volume while failing to reduce the actual number of new lesions remains.

“Further studies will further determine the role of TriGuard embolic deflection device in preventing ischemic brain injury during TAVR and other cardiac causes,” he said.

Silent Ischemia Remains a Problem

Dr. Mullen noted that TriGuard and similar devices are being explored in response to the high incidence of silent ischemic events post TAVR. “There is increasing evidence that they have long term sequelae related to neurocognitive function,” he said. “And I think it’s fairly obvious that much of these emboli to the brain occur during the TAVI procedure either related to atheroma within the aortic arch or tissue coming from the valve itself during the TAVI procedure.”

In response to an audience question, Dr. Mullen acknowledged that in some cases, a deflection device such as TriGuard may not be of much help.

“We’ve all seen on [transesophageal echocardiography] in TAVR patients that sometimes they have nasty vessels, and of course this is only one approach to prevent brain embolization,” he said. “Clearly there are some strokes that occur in the 24 hours after you’ve removed the device, and it won’t protect against those if you’ve got friable plaque in the aorta. We’ve still got some ways to go before we understand fully how we can prevent stroke and reduce the incidence of cerebral ischemia following these procedures.”

 

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Source:
Mullen M. First report of the DEFLECT I Trial. A prospective, single-arm feasibility study to evaluate the safety and performance of the Keystone heart TriGuard Embolic Deflection Device in patients undergoing transcatheter aortic valve replacement (TAVR). Presented at: EuroPCR; May 22, 2013; Paris, France. 

 

Disclosures:

• The study was sponsored by Keystone Heart.
• Dr. Mullen reports serving as a consultant for Edwards Lifesciences and Nobles Medical Technology, and receiving research support from Abbott Vascular, Direct Flow Medical, Edwards Lifesciences, and Keystone Medical.

 

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