After using a new PFO closure device on opposite sides of the globe, two cardiologists say they are not surprised that the Coherex FlatStent EF PFO Closure System has received a CE mark for use in closing patent foramen ovales (PFOs).

Coherex Medical (Salt Lake City) reported Wednesday that the device has been granted a CE mark for use in Europe and other countries to close PFOs, a common defect found in roughly 20% of the worldwide population. Although many adults with PFOs never have any problems because of the defect, the condition is linked to strokes and migraine headaches.

Coherex said it has begun initial efforts to ramp-up sales and marketing in Europe for the FlatStent EF device. According to the company, the device is similar in use and function to self-expanding vascular stents that are widely used by interventional cardiologists. However, the FlatStent EF device combines a planar Nitinol structure with a polyurethane substrate in a unique fusion of PFO closure mechanisms designed with the intent to naturally seal PFO tunnels, Coherex said.

The company believes it is the first device cleared by any regulatory body that operates almost entirely in the PFO tunnel, allowing doctors to treat the condition from within the PFO tunnel itself.

"Current devices on the market are not bad devices, but they are an older technology," Randall Jones, MD, chief medical officer at Coherex, told Medical Device Daily. He said all of the current devices for PFO closure are at least 15 years old and were developed originally to close atrial septal defects, not necessarily PFOs. With the FlatStent EF device, Jones said, "we're just treating the tunnel, not the whole septum."

Compared to the older devices, the FlatStent EF contains a lot less foreign material and therefore there are fewer chances for problems, Jones said.

Horst Sievert, MD, principal investigator of the COHEREX-EU clinical study using the FlatStent EF system, said the device is unique among PFO closure technologies in the way it is used to repair PFO.

"The most common approach taken today for repairing a PFO is to use a device that clamps two metal mesh-like disks on either side of the PFO opening, with these disks exposed inside the left and right atria (or upper chambers) of the heart," Sievert said. "And to be clear, this approach works. However, anytime you insert any foreign object into the heart, there are several risks, including: blood clot formation, damage or erosion of the septal wall that separates the left and right atria, and even the potential for interfering with the electrical signals within the heart muscle itself."

Sievert said these risks appear to be reduced with the Coherex FlatStent EF device. "In fact, the Coherex FlatStent EF is the first in-tunnel device to receive regulatory clearance for PFO closure," he said. "Its rapid exchange system allows a physician to deliver the Nitinol and polyurethane structure of the FlatStent EF quickly and easily to the PFO where it can easily be maneuvered within the PFO tunnel before its anchors secure it into place — and that's the key. As a result, there is very little exposed surface area within the left atrium, little or no damage to the septal wall, and significantly less metal mass than current devices. The rapid exchange design also reduces the risk of introducing an air embolism into the left atrium by eliminating the need for a large bore delivery catheter common to other devices."

The COHEREX-EU study – a clinical trial conducted by Coherex to pursue CE mark clearance for the device – was conducted at sites in Germany, Switzerland, New Zealand and Australia. Sievert is the director of the CardioVascular Center Frankfurt, Sankt Katharinen, and the Department of Internal Medicine, Cardiology and Vascular Medicine of the Sankt Katharinen Hospital (Frankfurt, Germany). He is also an associate professor of internal medicine/cardiology at the University of Frankfurt.

Another physician who participated in the study was Peter Ruygrok, MD, clinical director of the Green Lane Cardiovascular Service at Auckland City Hospital (Auckland, New Zealand). Ruygrok is also on staff at the Auckland Heart Group, a private cardiology practice in New Zealand.

"I was delighted with the high rate of closure immediately after implantation, something I was not expecting, but I suspect we saw such results because the Coherex FlatStent EF functions almost entirely within the PFO tunnel," Ruygrok said. "Six months after implantation, it was clear the Coherex device functioned exactly as we had anticipated – the PFO tunnels were closed, there was no more shunting of blood from the right to left atrium, and no damage to the septal wall. The final results were very encouraging and that's what I was hoping for from an in-tunnel device like the Coherex FlatStent EF."

A foramen ovale is a tunnel-like opening between the upper chambers of the heart that allows blood to bypass the lungs and is present in all fetuses, Ruygrok said. Normally, the foramen ovale closes soon after an infant is born. However, if this opening fails to close naturally after birth the opening is said to remain patent and the defect is called a PFO.

Trent Loveless, CFO at Coherex, told MDD that the company has been in discussions with FDA and is also working with world leaders in neurology and cardiology in an effort to design a migraine trial which could show a connection between migraine and PFO and being able to improve the symptoms of migraine using this device. "We anticipate being able to begin a trial with FDA in the near future, although we don't have any fixed dates that I can give you at this time," he said.

Coherex has already begun its initial efforts to ramp-up sales and marketing in Europe for its Coherex FlatStent EF, and the company expects to make future announcements about its progress as it moves forward in these areas.

"Although there are a handful of older, legacy devices cleared for closing PFOs, these devices are significantly larger than the Coherex FlatStent EF and they close PFOs by completely overlapping PFO openings on both sides of the septal wall," Richard Linder, Coherex president/CEO said in a company statement. "Conversely, by its very design, the Coherex FlatStent EF represents the next generation approach to PFO closure." Linder added that the FlatStent has "dramatically less mass and less exposed surface area" than other PFO closure systems and is deployed almost entirely within the PFO tunnel – the exception being two tiny anchors.

"The device works just like it was designed to and really offers patients a benefit and advantage that they haven't had until now," Jones said.