Cook Medical (Bloomington, Indiana) has received conditional FDA approval for a trial of a radically smaller endograft delivery system that would make endovascular aortic repair (EVAR) available to more patients.

The company has received Investigational Device Exemption (IDE) conditional approval to begin a 120-patient clinical trial for its Zenith Low Profile Abdominal Aortic Aneurysm (AAA) Endovascular Graft.

The trial, which will include 24 sites, is designed to evaluate the safety and effectiveness of the smaller endograft delivery system, enabling the endovascular treatment of AAA patients with smaller vascular access vessels who otherwise may not have been candidates for minimally invasive endovascular treatment.

Cook reported the news at the VEITHsymposium being held at the New York Palace Hotel.

"This is a significant change," David McCarty, Cook's global public relations director, told Medical Device Daily. "The smaller it is, the easier the delivery, particularly for smaller people such as women and Asians."

Larger systems have to be introduced via a surgical incision to the femoral artery. The 16 Fr delivery sheath in the Zenith is small enough to do it via percutaneous entry, sliding a guidewire through a needle.

"But this also is for all patients and it's really the 'Holy Grail' for AAA endovascular surgery because it reduces the risk of infection, reduces the time of the procedure and the time to recover," McCarty said.

"We are thrilled to receive the green light from the FDA to move forward with a clinical trial for the Zenith Low Profile AAA Endovascular Graft," said Phil Nowell, global leader of Cook's aortic intervention strategic business unit. "We look forward to initiating this trial that brings greater precision and ease of delivery to EVAR."

The current system used by Cook and other companies is 20 Fr to 24 Fr, compared to the Zenith's 16 Fr sheath size. The smaller size reduces the need for a surgical cut-down to access the femoral artery for device insertion.

Assuming it is approved, the Zenith Low Profile gives physicians the opportunity to serve an additional subset of patients previously ineligible for endovascular treatment due to anatomical restrictions in addition to offering the less invasive approach to all patients.

The FDA responded quickly to Cook's request for the IDE trial, which was made earlier this month (MDD, Nov. 7, 2008).

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

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

Also at the VEITHsymposium:

• W.L. Gore & Associates (Flagstaff, Arizona) reported that it has received regulatory clearance from Health Canada's Therapeutic Products Directorate to market the Gore Excluder AAA Endoprostheses and Gore TAG Thoracic Endoprosthesis in Canada.

The company said planning is under way for Canadian physician training on the devices, and the subsequent commercial product release timeline will be announced in the near future. The Gore Excluder and the Gore TAG Thoracic Endoprosthesis devices were previously granted regulatory approval in the US, Europe, Japan and South Korea.

The Gore Excluder endoprosthesis is an implantable device indicated for the endovascular treatment of AAA, a condition caused by the degenerative weakening and dilation of the abdominal aorta. The Gore TAG Thoracic Endoprosthesis is an implantable device used to treat TAA, or an aneurysm of the descending thoracic aorta, the body's main circulatory vessel.

Gore said TAA is a life-threatening condition generally believed to be significantly under-diagnosed, and patients with TAA are at risk of death due to internal bleeding resulting from a ruptured aorta.

The company noted that until recently, treatment for AAA and TAA required invasive, large-incision surgery and a lengthy hospital stay to repair the diseased or damaged artery. "With the Gore Excluder AAA Endoprosthesis and the Gore TAG Thoracic Endoprosthesis, aneurysms can be prevented from rupturing through a minimally invasive procedure, thereby reducing the hospital stay, morbidity and mortality associated with surgery," it said in a statement

"Gore is pleased to expand its international efforts to improve patient care for both AAA and TAA, with less-invasive treatment alternatives for the Canadian patient population," said John Sininger, leader of the Gore Medical Products Division.

Clinical data from a prospective registry presented at the symposium shows deep vein thrombosis (DVT) treatment with the Trellis Peripheral Infusion System from Bacchus Vascular (Santa Clara, California) successfully breaks up the blood clot in most patients in about 20 minutes.

This technique, called isolated pharmacomechanical thrombolysis, restores blood flow more quickly and safely than current catheter-directed thrombolysis (CDT) techniques, Bacchus said. "It provides an important adjunct to anti-coagulation alone, the current standard of care, which does not break up the existing clot but simply prevents further clot from forming."

Alan Dietzek, MD, chief of vascular and endovascular surgery at Danbury Hospital (Danbury, Connecticut), reported the latest outcomes from the manufacturer's registry of clinical results with the Trellis System at more than 360 hospitals in the U.S. and internationally.

In a total of 1,409 limbs treated in 1,304 patients, Grades II and III lysis with restoration of patency in patients with all clot chronicities were achieved in 95% of cases. The vast majority of cases (more than 83%) were completed in less than two hours in the setting of an interventional suite, and the usage of the Trellis System was typically around 20 minutes.

Dietzek said no follow-up monitoring in a costly critical-care or intensive-care unit was typically needed with the Trellis System, in contrast to that requirement in CDT procedures.

He said there were no reported bleeding complications related to the Trellis device in acute follow up and the dosage of thrombolytic drugs such as tPA was reduced by 30% with use of the Trellis device compared to CDT.

Dietzek said, "New clinical guidelines in 2008 from the American College of Chest Physicians and the National Quality Forum support the early removal of blood clots with devices like the Trellis System and clinical data on the use of the device underscore the importance of its growing role."