Gore gains FDA approval for dual fluoropolymer/nitinol stent

W. L. Gore & Associates Inc. (Flagstaff, AZ) today announced approval of the Gore Tigris vascular stent by FDA. The device, which has had the CE mark since 2011, is a third-generation self-expanding stent with a unique dual fluoropolymer/nitinol design. “Other self-expanding uncovered stent designs on the market typically only use nitinol,” Ray Swinney, Peripheral Interventional Business Unit Leader at Gore, told PlasticsToday. “To the best of my knowledge there are no other self-expanding uncovered stents that use fluoropolymers.”

The device was designed explicitly to conform with the natural movement of the knee when treating peripheral artery disease (PAD).  

The dual-component stent is made from a single-wire nitinol stent with flexible and biocompatible fluoropolymer interconnections. “Standard metal stents use metal interconnections, which are much stiffer than the fluoropolymer,” said Swinney, adding that the dual-component design contributes to the flexibility of the device.

The stent is designed to weather biomechanical forces (extension, compression, flexion and torsion) without fractures, even in the most complex anatomies, namely in the superficial femoral artery (SFA) and proximal popliteal artery (PPA), according to Gore. In the U.S. clinical study that supported FDA approval, the Tigris stent was found to have zero fractures, while the control arm devices experienced a 27% fracture rate.

“The extreme flexibility of this stent makes it well suited for the superficial femoral artery and proximal popliteal artery, and the delivery system is highly accurate,” according to John R. Laird, MD, an interventional cardiologist in Davis, CA, who is quoted in a press release issued by Gore. “The precision offered by this flexible, dual-component device allows for easy insertion and predictable clinical outcomes, even in a challenging anatomy.”

The new device also features Gore's CBAS Heparin Surface, a heparin-bonding technology designed to resist thrombus formation, a problem common in both bare metal and drug-eluting stents. End-point covalent bonding keeps heparin anchored to the stent surface, while the bioactive site remains free to interact with the blood to help prevent clotting.

The evolution of peripheral stenting over the past decade has allowed for broader adoption of endovascular therapy for treating PAD, noted Gore. When physicians began placing stents in the SFA they were limited by first-generation stent designs that had longitudinal metal connections, which led to arterial stiffening, high fracture rates and poorer clinical outcomes. Improvements in second-generation devices introduced helical interconnections to improve flexibility; however, their success in high-flexion vessels, like the distal SFA and PPA, was still limited. The introduction of third-generation stents, including the Gore Tigris vascular stent, allows for better adherence in some of the more intricate vessels in the body.

Approximately 8 to 12 million people suffer from some form of PAD in the United States alone. The disease can manifest in mild symptoms such as chronic leg pain, and more serious complications include poor wound healing, increased risk of stroke and amputation. Endovascular treatment, via angioplasty and stenting of a blocked artery, is designed to treat PAD without the complications that can accompany open surgery.