Medical Device Daily

On the surface Cook Medical’s (Bloomington, Indiana) Zenith Dissection Endovascular System could be viewed as a single device. But the system, which recently received clearance for a Phase I clinical trial, is actually a two-pronged approach in performing aortic endovascular repair.

“This [system] is really two devices in one,” Ray Leonard, the Senior Product Manager of Cook’s Aortic Intervention business unit, told Medical Device Daily. “It’s comprised of a catheter, loaded with a self-expanding, fabric-covered stent-graft and bare metal stent. The novelty is, the combination of these two devices is very disease-specific and is a holistic approach to aortic endovascular repair.”

Cook last week reported launch of enrollment in the STABLE clinical trial to evaluate the system for the treatment of Type B thoracic aortic dissections. The company reported FDA approval to begin the three-center U.S. Phase I trial in October (Medical Device Daily Oct. 1, 2007).

The company says that the device is the “first of its kind” and designed specifically to treat aortic dissection.

The Dissection Endovascular System, looking a bit like a thin-wire slinky, but covered in a cloth-like mesh, is intended for use in the endovascular treatment of descending thoracic aortic dissection, but, as the company qualifies it, only “in patients with anatomies appropriate for endovascular repair.”

Using the system, physicians insert a catheter loaded with the self-expanding stent-graft (called the TX2) through a surgical opening in the femoral artery. The catheter is then guided through the patient’s blood vessels under fluoroscopy until the device is positioned across the weakened section of the aorta.

The stent-graft expands upon deployment from the catheter to form a continuous tube through the aorta that carries the blood and reduces pressure on the damaged vessel, restoring normal blood flow. The uncovered Zenith Dissection Stent may be used to expand the true lumen in the distal thoracic aorta where preservation of the side branch artery blood flow is critical.

In essence, the TX2 Stent Graft repairs the primary entry tear while the bare metal dissection stents were placed to expand and support the remainder of the dissected aorta for the length of the dissection (in this case to the level of the aortic bifurcation).

“It is the bare metal stent that helps preserve the flow to these branch arteries,” Leonard said. “The difference in other procedures is that without the bare metal stent you’re not offering protection to these branches – and that loss of protection could prevent proper spinal circulation, which could in turn cause paraplegia.”

The STABLE trial will include 15 subjects across the three U.S. sites, its principal investigators being Joseph Lombardi, MD, of Thomas Jefferson University (Philadelphia), Anthony Lee, MD, of the University of Florida (Gainsville) and Richard Cambria, MD, of Massachusetts General Hospital (Boston).

The company said that it was hoping for Phase I of STABLE to be completed within six months and hopefully garner FDA approval by 2010. The first STABLE trial patient was treated by interventional radiologist Peter Mossop, MD, and cardiac surgeon Ian Nixon, MD, at St. Vincent’s Public Hospital (Melbourne, Australia).

The first patient found suitable for inclusion in the Stable dissection clinical trial was a 60-year-old male diagnosed with a Type B dissection of his thoracic aorta. The company would not comment on how many patients it expects to enroll.

Barry Thomas, VP of Cook’s Aortic Intervention strategic business unit, said, “With the highly skilled support of Dr. Mossop and Dr. Nixon, we are continuing our efforts to better serve patients affected by thoracic aortic dissections across the world with the most minimally invasive treatment available. As this condition affects tens of thousands of lives annually, we look forward to helping more patients avoid the trauma of open surgical repair and go on to live healthy lives.”

The system hasn’t received CE-mark approval yet.

Stable isn’t the only clinical trial that Cook is banking on with the Zenith platform.

The company also reported last week that it is asking the FDA for permission to initiate another clinical trial derived from the Zenith line.

The request is for the Zenith Branch Endovascular Graft-Iliac Bifurcation to be used with the H&L-B One Shot Introduction System at 10 sites. This application is geared toward treating patients with aortoiliac or iliac aneurysms that have been difficult to treat endovascularly with current designs.

The company said once the application has been reviewed and approved, Lee, the national principal investigator, will lead the trial, along with a select group of U.S, vascular surgeons at healthcare institutions around the country. This trial is expected to take about one year to enroll.

Cook is focused on developing biopharma, gene and cell therapy products, and biotech products.