Medical Device Daily Associate

Cook (Bloomington, Indiana) has received FDA approval for its new 36 mm Zenith Flex AAA endovascular graft system for the treatment of abdominal aortic aneurysms (AAA), company officials reported last week.

The new device is designed to provide a minimally- invasive treatment option for patients with large abdominal aortic neck diameters who previously may not have been candidates for endovascular aortic repair (EVAR).

With FDA clearance of the system — which includes the 36mm Zenith Flex AAA Endovascular Graft and the 22 French H&L-B One-Shot Introduction System with Flexor Sheath and Captor Hemostatic Valve — Cook said that physicians can offer an endovascular solution for the interventional treatment of AAA in large aortic necks ranging from 29 mm to 32 mm in diameter.

Barry Thomas, director of endovascular therapies for Cook, told Medical Device Daily that this new device will treat an additional patient population equal to about 10% of the current market for these grafts. He acknowledged that while this doesn't represent a huge market opportunity, it validates the company's goal to provide systems for every aspect of the AAA graft market.

"It's part of the whole Cook philosophy of treating all patients that need treating, based on the need, rather than only looking at the financial side of things," he said.

According to Thomas, this new system represents the "largest abdominal device available in the world." He noted that while patients with large aortic necks may not necessarily be the most difficult group to treat, they are "more difficult to access" in a minimally invasive fashion.

He said that the ability to make this new system work was the company's Flexor slip-coated sheath delivery system, which the company plans to make available for other graft sizes in the U.S. in the near future.

"When we sat down and worked it through, having the Flexor available in the larger sizes was the key to being able to get this product into the market. The standard non-slip-coated non-Flexor delivery systems would have made it much more difficult."

Key problems that other companies have had in this market often have not been with the grafts themselves but rather with the delivery method, Thomas told MDD. He said that "high-profile devices no longer on the market" had problems with delivery that Cook has taken pains to avoid.

"Cook has always had a very good reputation, catheter-wise, in the delivery systems and that whole area," he said. "In Australia we developed this [next generation] around the delivery system, so you can put it exactly where you want it and deploy it correctly. The Cook device has two more steps than any other device, but those steps allow us to control the device."

While Thomas said Cook has pursued coverage of the entire AAA graft market, he acknowledged work still to be done, particularly in the U.S. in the area of fenestrated grafts.

The fenestrated graft is unique in its architecture, he said, with a particular approach to construction needed to fit difficult aneurysms.

The treating physician first uses a variety of imaging techniques to describe the anatomy of the aneurysm, and this description is then sent to Cook's Australian facility that uses specialized techniques to create a custom endograft. A customized design, he said, is needed for the short difficult "necks" of the diseased anatomy "between the bottom margin of the renal artery and the top margin of the expansion of the aneurysm." These shorter necks, Thomas said, are found in "a particular range of patients" who can't be treated with standard AAA grafts, which are susceptible to endoleaks.

The company has completed a Phase I trial for the fenestrated device and is working with the FDA to put together a Phase II trial, Thomas reported.

Cook estimates that the AAA market as a whole is worth $350-$400 million in the U.S. and about $225 million in the European market which is largely under-penetrated.

He said that company is also is moving forward with a few implantations of its TX2 device to treat thoracic aneurysms, which he called "not a huge business market" but nevertheless extremely important for those with this type of aneurysm. In that market, the company has finished its U.S. clinical trials and hopes to submit a PMA application to the FDA later this year.

In the U.S. the company competes with Medtronic (Minneapolis), with its AneuRX system, and W.L. Gore (Flagstaff, Arizona), which makes the Excluder.

AAA, a life-threatening disease, occurs when a section of the abdominal aorta, the body's main circulatory vessel, weakens and bulges outward to form a balloon-like swelling called an aneurysm. If the aneurysm ruptures, the patient is at high risk of death as a result of internal bleeding.

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