|Claret Medical's Sentinel Cerebral Protection System|
The first day at the recently concluded Transcatheter Cardiovascular Therapies (TCT) meeting in Washington, D.C., was reportedly heavily focused on TAVR - transcatheter aortic valve replacement therapies. Analyst reports emerging from of the event show that they believe that more clinicians are going to be persuaded to use the TAVR procedure on younger patients who may not be at risk to undergo the alternative, more invasive procedure - open heart surgery. All this is sweet music to a California startup Claret Medical, whose near term future is tied to the fate of TAVR, and which also presented at TCT.
The company is developing the Sentinel Cerebral Protection System device to catch embolic debris that results from any TAVR procedure. Such debris has the potential to cause stroke, one of the major complications of TAVR today. Claret's Sentinel is a temporary device comprising a catheter and two filters that can capture and retrieve the debris that may otherwise flow to the brain.
In a phone interview before the TCT meeting, the Santa Rosa company's CEO, Azin Parhizgar, says Claret Medical plans to launch a U.S. pivotal trial in October to test the efficacy of the Sentinel device. At TCT, some evidence of its capability was already demonstrated through a European trial.
In a late-breaking clinical trial session, Dr. Alex Linke, the European trial's principal investigator and a professor at the University of Leipzig, presented results that showed that the device significantly reduced the number and size of brain lesions. That was confirmed with MRI scans after following the TAVR procedure.The randomized, controlled, double-blinded trial showed that there was a 53% reduction in the "total volume of new brain lesions and a 60 percent reduction in the number of new brain lesions two days after the procedure," according to a Claret Medical press release.
"There are three vexing problems still with TAVR and one is high stroke rate," Parhizgar says. "If you have a device that can help bring stroke rate down to zero, then it would be almost immoral not to do that." [The other two she says are paravalvular leak, widely noted in clinical literature as well as vascular complications.] She adds that TAVR devices are bulky and end up scraping various arteries, valves and ventricular tissue thereby heightening the potential for stroke.
Recognizing this, Medtronic and Edwards Lifesciences are striving to bring smaller profile TAVR products to the marketplace. One such is Medtronic's CoreValve Evolut R. A cardiologist who is one of the national investigators testing the device in a U.S. pivotal trial was aware of Claret Medical's filtration device and its potential contribution to make TAVR procedures safer for the patient.
"If Claret Medical's technology is proved to be effective, there will probably still be a role for it despite smaller devices," says Dr. Matthew Williams, chief of adult cardiac surgery and director of interventional cardiology and structural heart at NYU Langone Medical Center in New York City.
So what type of debris does the Sentinel Cerebral Protection System, which has the CE Mark, catch?
So far, the filters that are placed in the carotid arteries right before the TAVR procedure have captured mainly human tissue, explains Parhizgar. That includes pieces of the aorta, deteriorated heart valves and even ventricular tissue.
But the device has also caught some foreign material, which Parhizgar describes as most likely coatings from the catheters being used in the TAVR surgery. Claret's device has been used in 800 procedures. In the Cleantavi trial, the device was used with Medtronic CoreValve systems of various generations.
Claret Medical is not the only company trying to develop a system to make the overall TAVR procedure safer for patients. Parhizgar pointed to two other products - the Embrella Embolic Deflector System that Edwards Lifesciences has acquired and the TriGuard Cerebral Protection device developed by Keystone Heart - that compete with the Sentinel system. But Parhizgar says that there is an important distinction between Claret's filter device and these products.
"These devices deflect, but do not remove debris from circulation," she says. "Claret Medical’s Sentinel Cerebral Protection System is the only filter device that captures and removes debris from circulation in TAVR."
An animation of the TriGuard device on the Keystone Heart website appears to support this claim.
That claim will of course be tested in the pivotal trial that Parhizgar plans to launch in October. The trial will be conducted in up to 15 centers, enroll up to 300 patients and follow each patient for 30 days.
Her hope is that once Claret is able to prove the efficacy of the device in larger patient populations, and clinical evidence mounts, regulation will mandate the use of such cerebral protection devices with all TAVR procedures. That would make the procedure similar to another cardiovascular operation.
"Cerebral protection use is mandatory in carotid artery stenting performed in the U.S.," Parhizgar says.
"Right now, though, the focus and attention of the company, which has 27 employees, is on the pivotal trial in the U.S.
We are projecting finishing enrollment in Q3 of next year," Parhizgar says.