Medical Device Daily

Nearly 300 patients are subject to take part in the W.L. Gore (Flagstaff, Arizona) REVISE clinical study, which started earlier this month.

According to the company, the study is a randomized, multi-center trial used to establish the efficacy and safety of the Gore Viabahn Endoprosthesis with Propaten Bioactive Surface to revise arteriovenous (AV) grafts at the venous anastomosis in hemodialysis patients.

The study randomizes patients to the Gore Viabahn Endoprosthesis with Propaten Bioactive Surface and to percutaneous transluminal angioplasty (PTA). The study is expected to have up to 280 subjects, with 140 subjects in each treatment arm spread out over 30 sites. It is slated to be completed in 2012.

"This study will provide the clinical community with valuable data on the performance of this heparin-bonded stent graft for AV graft revisions, rather than PTA alone," said Andrew Nish, MD. "The study is designed to show any difference in time between interventions when using stent grafts to treat venous outflow stenoses."

"The Gore Viabahn Endoprosthesis is a flexible, metallic (made from nitinol) tubular shaped device stent which is lined with plastic (made from expanded polytetrafluoroethylene," Susan Boothe, RN, product specialist at Gore, told Medical Device Daily.

The company received originally FDA approval to market the device to treat periphriel arterial disease in the superficial femoral artery last year.

The device, which has been implanted in more than 90,000 patients worldwide is mounted on the end of a delivery catheter and held in place by a release mechanism.

"The study will provide further insight into addressing clinical issues in dialysis access patient populations," Boothe said. "The fact that the study design permits the use of the device across the elbow joint makes this study unique."

Here's how the device works:

The delivery catheter with the mounted Gore Viabahn Endoprosthesis is inserted in the femoral artery through a puncture in the leg and threaded to the blocked section of the femoral artery.

Once the device is positioned within the blocked area, it is freed from the delivery catheter by activation of the release mechanism.

The device is expanded within the artery , opening the blocked area to improve blood flow.

The delivery catheter is removed from the patient, leaving the device within the femoropoplitealartery of the patient.

The device was initially approved by the FDA in 2005 for treating SFA disease and, in 2007, two modifications to the device, a lower profile and a heparin bioactive surface, were approved. The excellent flexibility of the Gore Viabahn Endoprothesis enables it to traverse tortuous areas of the SFA and conform to the complex anatomy of the artery.

The iliac occlusive disease treatment deignation was obtained using data collecting Iliac as part of the Gore Viabahn Endoprosthesis Feasibility Study that was conducted in the U.S. and Europe from 1996 to 1999. Data collected from this study was used to establish the endoprosthesis as safe treatment of iliac arterial occlusive disease when used in accordance with its labeling.

The Gore Viabahn product also has a designation to be used in patients who have a blockage within their femoral artery, which is caused by atherosclerotic disease. This blockage can cause pain by preventing adequate blood flow from reaching the lower leg and foot. The Gore Viabahn Endoprosthesis is indicated for improving blood flow in patients with symptomatic peripheral arterial disease in superficial femoral artery lesions with reference vessel diameters ranging from 4.8 mm to 7.5 mm.

Gore has had success with its clinical trials as of late. In the ongoing Propaten vascular graft studies, it has reported primary patency rates as high as 79% at one year for below-knee bypasses (Medical Device Daily, July 23, 2008) In comparison, prior to the Propaten vascular graft being available, non-heparin-bonded synthetic grafts achieved an average primary patency rate of 66% in below-knee bypass procedures at one year.

Gore said these "encouraging" interim results were presented to clinical audiences at the annual meeting of the Society of Vascular Surgery (SVS; Chicago) in San Diego.

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