CD&D and Staff Reports

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 Cardiovascular Devices & Drugs 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 aneur-ysms 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.

"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 CD&D.

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."

Elsewhere in the product pipeline:

  • Ascent Healthcare Solutions (Phoenix) saidit has received the industry's first 510(k) clearance from the FDA to reprocess the Lasso 2515 variable circular mapping catheter manufactured by Biosense Webster. With this new clearance, Ascent said it continues to increase its portfolio of EP catheters to offer EP cath labs the ability to most effectively manage their resources while ensuring that clinicians have access to their preferred device to most effectively diagnose arrhythmias. The Biosense Webster Lasso 2515 variable circular mapping catheter has been designed to facilitate electrophysiological mapping of the atria of the heart and is deployed in the right or left atrium. The catheter features a variable loop that easily adjusts to any vein sized between 25 mm and 15 mm. Its adjustable tip provides efficient mapping and is also deflectable for maximum movement. It is available in 10-electorde and 20-electrode configurations. These devices will be the first line of reprocessed diagnostic EP catheters to be packaged in Ascent's thermoformed tray, which has a design that provides greater protection during transit and storage for these catheters with complex curves.
  • Cardiac Science (Bothell, Washington) reported the launch of the fourth generation of Burdick HeartStride exercise stress systems. This new version adds echo and nuclear systems connectivity to the existing connectivity with EMR/other systems. "With the connection to echocardiography and nuclear devices," said Ren Mitchell, Cardiac Science director of diagnostic marketing, "HeartStride allows the stress and imaging systems to use the same ECG signal. That's significant. Now the systems base their assessments off the same tracing."
  • LifeNet Health (Virginia Beach, Virginia) said it has received FDA clearance for CardioGraft allograft cardiac patch products with MatrACELL decellularization technology. LifeNet Health received clearance for the technology for cardiac products, which safely removes donor cells from cardiovascular tissues while retaining the native biomechanical strength of the tissue.
  • Medtronic (Minneapolis) reported the U.S. market launch of the Talent thoracic stent graft on the Xcelerant delivery system, which the company says makes minimally invasive treatment of thoracic aortic aneurysms easier to perform. The Talent system is designed to provide a minimally invasive alternative to open surgery for patient's with life-threatening aneurysms in the upper portion of the aorta, the body's largest artery. Thoracic endovascular aortic repair (TEVAR) is a procedure in which a stent graft is threaded through the femoral artery and expanded at the site of the aneurysm, Medtronic said. Once in place, the stent graft creates a new path for blood flow, reducing pressure on the aneurysm and the risk of rupture. Left untreated, aortic aneurysms can burst, an emergency situation that commonly results in death due to extensive internal bleeding, the company noted. Tony Semedo, VP and general manager of Endovascular Innovations, part of the CardioVascular business at Medtronic, told CD&D that the wide diameter range – from 22 mm to 46 mm – of the Talent graft makes the device unique compared to competing devices because it makes TEVAR procedures available to an additional 25% of patients. FDA approved the Talent stent graft in June for certain aneurysms of the descending thoracic aorta, but it has been available outside the U.S. since the late 1990s. As for the Xcelerant delivery system, Semedo said it has a "twist-and-release" design which "allows us to deploy the stent graft from the top, or proximal end, of the of the stent graft down" for a more controlled deployment compared to the more traditional method of deploying the stent graft from the middle to the ends.
  • MIV Therapeutics (Atlanta), which believes removing the polymer from drug-eluting stents (DES) is at least one way of addressing the safety concerns surrounding the technology, reported that the Journal of the American College of Cardiology Intervention (JACC) published preliminary results from its first human trial. The VESTASYNC I trial, which evaluated MIV Therapeutics' polymer-free DES, appeared in the Oct. 21 issue of JACC. Author J. Ribamar Costa Jr., MD, describes the results from the four-month follow-up of a multicenter, 15-patient, first-in-man study led by principal investigator Alexandre Abizaid, MD, PhD, chief of coronary intervention at the Institute Dante Pazzanese of Cardiology (Sao Paulo, Brazil). "The publication of the preliminary VESTASYNC I trial results in such a prestigious, peer-reviewed journal as JACC is clearly a vote of confidence in the soundness of our science," said Mark Landy, MD, president/CEO of MIV. "We are very proud to be included and to receive this tremendous recognition by the scientific community." DES makers have been in a race to address the safety issues surrounding DES ever since it became associated with a higher rate of thrombosis, or blood clotting. Before a company can truly solve the problem, however, it will have to get to the bottom of what is causing the higher rate of thrombosis – is it the drug itself or the polymer used to attach the drug to the stent? "From our perspective the one way to try and solve these issues is to eliminate the polymer and then once and for all we know if it's a drug issue or a polymer issue," Landy told CD&D. In the VESTASYNC I trial, MIV said, the VESTAsync DES was successfully implanted in all cases, and there were no procedure and in-hospital complications. Life-long aspirin and five-month clopidogrel therapy were prescribed for all patients. At four months, in-stent late lumen loss was 0.30 ± 0.25 mm and percent of stent obstruction was 2.8 ± 2.2%.
  • St. Jude Medical (St. Paul, Minnesota) reported the publication of a study on the St. Jude Medical Biocor stented tissue valve that found the valve provided excellent long-term durability as a replacement for the aortic valve in patients 65 and older. The study, which appears in the October issue of the Annals of Thoracic Surgery, evaluated the 20-year durability of the Biocor porcine valve in the aortic position. According to the study, over the 20-year follow-up period, the Biocor valve was found to perform well on key measures of long-term performance including freedom from reoperation due to structural valve deterioration (the rate at which patients remain free from another operation related to degeneration that could affect the valve's proper functioning).