Cerebral Protection Device — A Safe Option In Preventing Ischemic Strokes

A recent research, funded by Claret Medical to test the efficacy of its Claret Montage Dual Filter System, shows that in patients at a higher risk of aortic stenosis undergoing transcatheter aortic valve implantation (TAVI), the use of a cerebral protection device reduces the frequency of ischemic cerebral lesions, a sub-type of stroke that leads to poor oxygen supply to brain tissue. The research was published in JAMA on Aug 9, 2016.

There is a high risk of fatality of cerebral injury following TAVI, a medical procedure in which the aortic valve in the heart is replaced.

The study was conducted in 100 patients to determine the effect of a cerebral protection device on the number and volume of cerebral lesions in patients undergoing TAVI. The researchers observed the numerical difference in new positive post-procedure DWMRI brain lesions at 2 days after TAVI in certain brain regions. The secondary measurement outcome was the difference in volume of new lesions after TAVI in certain areas of the brain. Brain MRI was performed at baseline, 2 days, and 7 days after TAVI.

Between April 2013 and June 2014, patients were randomly assigned to undergo TAVI with a cerebral protection device, which was the filter group, or without a cerebral protection device which acted as the control group. The last 1-month follow-up occurred in July 2014.

Transcatheter aortic valve implantation (TAVI) using the balloon-expandable SAPIEN valve has been shown to be superior to standard medical therapy in inoperable patients. Additionally, more recent data support that TAVI with the self-expanding CoreValve prosthesis is associated with lower mortality than surgical aortic valve replacement (SAVR) in high-risk patients. Despite significant improvement in TAVI procedures over the decades, stroke still remains a cause of concern for many health professionals. This concern is backed by diffusion-weighted magnetic resonance imaging (DWMRI) scans which have shown that ischemic strokes occur in 80% of patients that undergo TAVI operation, which is quite a significant number.

The use of a cerebral embolic protection device during the procedure significantly reduced the number of cerebral lesions in the potentially protected brain regions to 4 in the filter group compared to 10 in the control group. The trial was conducted at the Heart Center at the University of Leipzig, Germany, with written consent from the patients. Hence wearing a cerebral protection device during the TAVI procedure significantly reduced the frequency and volume of ischemic strokes.

There were, however, limitations to the study. Because of the nature of the procedure, the interventional team could not be blinded. Therefore, it is possible that differences in the management of the control group vs the filter group during the TAVI procedure might have had an impact on the results. A big limitation was that the cerebral protection device does not protect the left vertebral circulation, but at the time of the study it was the only device available.

Despite this limitation, the MRI scans were able to cover the entire region of the brain. Nevertheless, device refinement is necessary to enable complete cerebral protection. Larger studies are needed to assess the effect of cerebral protection device use on neurological and cognitive function after TAVI and to devise accurate methods providing more complete coverage of the brain to prevent new lesions.

There Have Been Other Studies To Test The Efficacy Of Cerebral Protection Devices

On October 15, 2015, Claret Medical announced the results of the MISTRAL-C study which highlighted the benefits of its Sentinel Cerebral Protection System (CPS) during TAVI. The results showed that unprotected patients have statistically worsening cognitive abilities after 5 days post-TAVI operation when compared to patients protected during the TAVI procedure with the SCPS.

The MISTRAL‐C study also validated findings from the landmark CLEAN‐TAVI study that showed the use of a Claret Medical cerebral protection system reduced the number and volume of brain lesions in TAVI patients. the MISTRAL‐C study showed a 52% reduction in the median total new lesion volume at five days post‐TAVI operation which was examined using highly sensitive 3‐Tesla brain MRI. None of the protected patients had National Institute of Health Stroke Scale (NIHSS) deterioration at five days post‐procedure, while 5% of unprotected patients showed deterioration.

Claret Medical has raised up to $18 million in Series B financing, led by Santé Ventures, a prominent healthcare focused venture capital firm. The proceeds were primarily used to finance the trial of the SCPS device.

Medicare Is Being Extra Cautious About The Devices When It Comes To Heart Patients

The Sentinel Cerebral Protection System (CPS) is a medical device that filters, captures and removes embolic debris, consisting of fibrin or amorphous calcium and connective tissue from the aortic walls, released during TAVI and other endovascular procedures that can lead to ischemic strokes. It has the potential for broad application in other structural heart procedures as well.

The Sentinel CPS is delivered to the brachiocephalic artery, and a distal embolic filter delivered to the left common carotid artery at the beginning of the TAVI procedure. The filters collect the debris and prevent it from travelling to the brain. After the procedure has been complete, the debris and filter is recaptured and removed from the patient’s arm. The device is available in a one size-fits all concept that adjusts to the vast majority of vascular anatomies. It’s important to know that this device is still in the investigational stage, and limited to investigational use by United States law.

The Wall Street Journal reported on Tuesday that Medicare has begun requiring that certain heart patients see a second physician before having a device called the Watchman implanted. The Watchman helps to control an irregular heartbeat in patients with atrial fibrillation, and Medicare explained that the idea is not to obtain a second opinion, but rather to ensure that the patients’ wishes are considered by a physician who will not implant the device. Hence certain measures such as these will doubly ensure patients’ health when it comes to medical devices enhancing heart operations.

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