When Cook Medical (Bloomington, Indiana) set out about 16 months ago to upgrade its TX2 device for thoracic endovascular aneurysm repair (TEVAR), the company looked at "all sorts of ideas," including a total redesign of the original device, Phil Nowell told Medical Device Daily. But in the end, the engineers came up with a "simple solution to what is a significant problem," he said.

Cook recently won FDA approval for its new Zenith TX2 endovascular graft with Pro-Form, designed to enhance control during TEVAR. Nowell says the device is a "very simple change" from the original, the difference being in the way the device deploys.

Nowell, the global business unit leader for Cook's aortic intervention division, said the goal of the upgrade was to address the need for better controlled deployment, a significant challenge facing physicians performing TEVAR today. In nearly 25% of thoracic aortic aneurysm (TAA) patients the aortic arch, which is formed like a reversed U, is exceptionally tight, making treatment difficult, he said.

According to Cook, physicians performing TEVAR with the new device can achieve greater levels of control during endograft deployment compared to the original TX2 device.

Cook says its new TX2 Pro-Form endograft utilizes an "improved delivery system that allows for carefully controlled deployment of the endograft to help establish proximal conformity of the device to the aortic wall." This innovation in endovascular TAA repair was engineered especially for procedures in which endografts must be positioned in tight aortic arches that are notoriously difficult to seal properly, the company noted.

Nowell said good control is important in TEVAR procedures because the reason other devices often have problems with migration is because of lack of control.

"Many physicians are familiar with the relatively common problem of thoracic endografts forming a 'bird's beak' gap along its underside when the graft is deployed into a tight aortic arch. With FDA approval of the Zenith TX2 TAA endovascular graft with Pro-Form, Cook is bringing an even more advanced version of its thoracic device to the U.S. market that addresses the need for highly controlled deployment, one of the most significant issues facing physicians performing TEVAR today."

According to the company, TAAs occur when the section of the aorta that runs down the chest weakens and bulges outward like a balloon, often caused by a hardening of the arteries, high blood pressure or trauma. Aneurysms in the thoracic aorta can result in severe internal bleeding and are potentially fatal; untreated, five-year survival is estimated to be between 10% and 15%, Cook said.

According to the company, many earlier endografts were too rigid or possess sealing stents that lack the radial force to conform correctly to the inner curvature of tight aortic arches, preventing the graft from properly sealing off the aneurysm. Consequently, surgeons have historically been forced to remodel the arch with a balloon or use other aids to position the graft, in an effort to reduce the risk of continued bleeding into the aneurysm and possible rupture. As a result, these difficult repair procedures are often long and complex. The TX2 Pro-Form's enhanced delivery system may mitigate the need for such additional measures, according to Cook.

"The physician has a device with controllability so they actually land the device where they intend to ... as they deploy the device it deploys where they intended it to go and that's about the delivery system, which is not quite the case with other devices," Nowell said.

In May Cook launched the TX2 Pro-Form in Europe and Nowell says the company is "very excited about the results we're seeing and physicians are talking to us about previously difficult arches that the Pro-Form seems to provide a good solution for."

But physicians in the U.S. will have to wait a while longer for the improved version of the device to be available. Nowell says Cook is looking towards a November launch for the product.

"I'll tell you a secret," Nowell told MDD with a chuckle. "We got FDA approval far quicker than we expected."

He laughed and admitted that the rapid approval surprised the company, so right now Cook is building its inventory before the product is officially launched.

According to Cook, the standard treatment for TAAs has historically been open surgical repair. Under this approach, the chest cavity is opened and the aorta is clamped, allowing the surgeon to sew a surgical graft into place to prevent a rupture. Open surgery for TAA can lead to serious complications and extended recovery times and also has a higher patient mortality rate than endovascular repair, the company noted.

With TEVAR, a minimally invasive alternative to open surgery, an endograft is guided into the body by a catheter to seal off the aneurysm from within. Patients undergoing TEVAR typically experience shorter recovery times, less patient discomfort and are also at a lower risk of the co-morbidities associated with open surgical repair, according to Cook. In particular, the Zenith TX2 device is inserted through a small incision in the groin to access the patient's femoral artery. The device is guided into position through the patient's arteries under fluoroscopy. The fabric-covered self-expanding stent-graft is then placed in the weakened section of the thoracic aorta to relieve pressure on the aneurysm to reduce the risk of rupture.

"We're working very hard to continue to find upgrades to our devices and new devices that provide greater TEVAR opportunity for patients," Nowell said.

Amanda Pedersen, 229-471-4212; amanda.pedersen@ahcmedia.com