Embolic Filter Reduces Cerebral Lesions During TAVI

September 13, 2014

WASHINGTON, DC — An embolic-protection device delivered percutaneously via the radial artery and used during transcatheter aortic-valve implantation (TAVI) in high-risk patients with aortic stenosis significantly reduced the number of cerebral lesions and lesion volume when compared with TAVI procedures performed without the filter.

These are the findings from the CLEAN-TAVI trial, a 100-patient study presented today by Dr Axel Linke (University of Leipzig, Germany) here at TCT 2014 . Of these patients, all of whom received the CoreValve (Medtronic), 50 underwent transcatheter aortic-valve replacement (TAVR) without embolic protection and 50 received embolic protection with the Sentinel cerebral protection device (Claret Medical). With the system, a proximal embolic filter is placed in the brachiocephalic artery and a distal embolic filter is placed in the left common carotid artery.

Speaking during a morning press conference announcing the results, Linke said the researchers examined by diffusion-weighted MRI the number of lesions in areas of the brain protected by the embolic device. They also investigated the number of lesions in the entire brain, because there is a small area supplied by the left cerebral artery that is not protected with the device.

At two days, there were 10 lesions detected in those undergoing TAVI without the filter vs four lesions in those who received embolic protection, a significant 60% reduction. At seven days, there were seven and three lesions in the control and filter arms, respectively. This difference was also statistically significant. When the entire region of brain was analyzed, and not just the protected region, the total number of lesions at two and seven days were significantly reduced in the filter-treated patients.

The results in both the protected and nonprotected regions of the brain were similar when investigators analyzed total lesion volume. Again, the outcome favored the filter-treated patients. In their neurocognitive assessment of patients, Linke said they observed lower rates of ataxia in the patients treated with the embolic protection device, and "this supports the notion that the filter has the potential to improve neurological outcomes."

Reduction in MRI End Point—Stroke Outcomes Not Known

Dr Axel Linke

Interestingly, the study showed a reduction in the total number of lesions and lesion volume from day 2 to day 7. "This study tells us that there is a natural evolution of the lesion," said Linke. "They tend to decrease in size, and some of the lesions do disappear. What is the physiologic reason for this? It's something we need to explore further."

Commenting on the results, Dr Jeffrey Popma (Beth Israel Deaconess Medical Center, Boston, MA) said the data are convincing as a proof of concept that embolic protection reduces particulate debris to the brain. Popma, who was involved in the initial studies with CoreValve, said that it is difficult to obtain imaging from TAVI patients, so these results will be welcomed by physicians. He noted that neurologists remain concerned about lesions detected at 48 hours even if they resolve. Even though there is resolution, the damage to the brain might have already been done, he said.

Dr Jeffrey Popma

Dr Alexander Abizaid (Institute Dante Pazzanese de Cardiologia, São Paulo, Brazil), who was not part of the study, said their center has been using this particular embolic-protection device for two years. When the device is removed after the procedure, debris is evident in 90% of cases. "So to prove this by MRI is very exciting for me," he said. CLEAN-TAVI, he said, is simply a mechanistic study, and bigger studies will be needed to determine whether the device reduces stroke rates rather than surrogate end points.

Dr Alexander Abizaid

In terms of safety, Linke said the mortality rate at 30 days was 1% in the entire cohort. He pointed out that these were slightly healthier patients than those enrolled in the CoreValve High-Risk cohort, with an STS score of 5.5% and a logistic EuroSCORE of 16%.

The SENTINEL investigational device exemption (IDE) study is currently ongoing in the US and Europe. A 15-center trial randomizing approximately 360 TAVI patients to treatment with the embolic filter or to TAVI alone is being led by Dr Samir Kapadia (Cleveland Clinic, OH) and Dr Susheel Kodali (Columbia University, New York). The primary end point is an assessment of cerebral lesions by MRI at four to seven days postprocedure.

The Sentinel cerebral protection system has CE Mark approval in Europe for use during TAVI procedures.

Linke reports grant and research support from Medtronic and Claret Medical and consulting fees/honoraria from Medtronic, St Jude Medical, Claret Medical, Boston Scientific, and Edwards Lifesciences. Abizaid reports grant and research support from Biotronik and REVA and consulting fees/honoraria from Abbott Vascular, Medtronic, and Boston Scientific. Popma reports grant and research support from Abbott Vascular, Boston Scientific, Cook Medical, ev3, and Medtronic and consulting fees/honoraria from Abbott Vascular, ev3, and Boston Scientific.

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