Cook Medical (Bloomington, Indiana) has submitted an Investigational Device Exemption application to the FDA for its new Zenith Low Profile Abdominal Aortic Aneurysm (AAA) endovascular graft. The device could bring the option of endovascular treatment of aneurysms to patients whose only current option is open surgery due to the small diameter of their blood vessels and other anatomic issues.

The Zenith Low Profile AAA endograft system employs a 16 Fr delivery sheath, significantly thinner in diameter than the current systems used by Cook and other companies, which are 20 Fr to 22 Fr.

With IDE approval, Cook said it would initiate a clinical trial to evaluate the safety and efficacy of the "radically smaller" endograft delivery system, that will permit treatment of AAA patients with smaller vascular anatomies who otherwise may not have been candidates for minimally invasive endovascular treatment.

Phil Nowell, global leader of Cook's Aortic Intervention strategic business unit, told Medical Device Daily that the new low-profile design is important for the AAA market for two reasons: first, because of the continuing desire for things to be less invasive, he said.

For example, endovascular treatment of aneurysms is less invasive than open surgery and now, by using a smaller size, Nowell said it is "quite possible" physicians won't have to make a surgical cut to access the femoral artery for device insertion, thereby allowing the use of the less-invasive percutaneous entry technique in many cases.

"It just gets less and less traumatic for the patient," he said. "Our goal is always to seek to provide options for more patients to have endovascular treatment."

Currently, Nowell said, about 60% of AAA patients have endovascular treatment, which means 40% are still having open surgery, at least partly due to anatomical reasons.

With the percutaneous entry technique, a needle is inserted into the blood vessel through the skin to enable the guidewire and delivery sheath to enter the artery with far less trauma and blood loss, Cook says. With the Zenith Low Profile, physicians can endovascularly serve an additional subset of AAA patients previously ineligible for endovascular treatment due to anatomical restrictions.

Cook reported the first human use of the Zenith Low Profile AAA endograft system in early June (Medical Device Daily, June 4, 2008).

"We're pretty happy that we've been able to go from that first human implant to submitting for an IDE approval so rapidly," Nowell told MDD.

He said Cook expects to get a response from the FDA within 30 days — but hopefully sooner — at which time the agency will either request more information or will tell the company to proceed with the trial.

If the Zenith Low Profile system ultimately wins FDA approval, it will be the smallest AAA endovascular graft on the U.S. market, Nowell said.

Currently, endograft delivery systems for abdominal and thoracic aortic aneurysms are inserted through the femoral arteries, as their diameters are typically too large to be inserted percutaneously. Cook says the Zenith Low Profile design enables physicians to navigate the device through narrow, tightly curved arteries to reach the aneurysm with potentially less risk of trauma to the patient's blood vessels.

It also will make treatment available for those patients who have a vascular anatomy too small to accept the current generation of larger delivery systems, particularly female patients and individuals of smaller stature, the company noted.

Nowell also cited the company's Zenith AAA Iliac Flex Legs and Z-Trak introduction system, for which Cook received FDA approval in August. Those products, made for use with the Zenith Flex AAA endovascular graft, are designed to improve flexibility and conformability in the aorta and iliac artery, a tortuous section of patient anatomy, for patients undergoing endovascular aneurysm repair.

The Flex Leg external stents are shorter than those of Cook's previous offering, with increased gaps between the stents — reducing the potential for the leg to kink (MDD, Aug. 5, 2008).

"All of these things are good news for patients," Nowell said. "We're very proud of the precision that our AAA devices have." He added that the Zenith Low Profile system "will have the same precision as you would expect from a Cook AAA device, but this is going to have a simplified deployment for physicians."