Non-Ablative Radiofrequency Endovascular Treatment For Peripheral Artery Disease; Guided Re-Shaping Technology (GRST™)

Non-Ablative Radiofrequency Endovascular Treatment For Peripheral Artery Disease; Guided Re-Shaping Technology (GRST™).

Author Block: Ronda E Schreiber, Michael F Hoey, Michael D Perry, Art G Blanck, Tom A Steinke, Sharon A Riddle, Corbett W Stone. Minnow Medical, Inc., San Diego, CA

Background
Conventional endovascular therapies for peripheral artery disease (PAD) such as stenting and atherectomy result in acute luminal expansion and increased blood flow. However, long-term restenosis rates remain a limitation of such procedures. GRST is a non-implantable device that utilizes non-ablative radiofrequency to mediate luminal opening and plaque reduction with low-pressure balloon expansion.

Methods
A Guided Re-Shaping Technology (GRST™), Minnow Medical, San Diego, CA) Peripheral Catheter System was developed to dilate and reduce plaque in the superficial femoral, popliteal, and tibial arteries. The GRST system consists of a sterile, single-use, over-the-wire percutaneous transluminal catheter (135 cm in length) with an angioplasty balloon (2.0 cm in length and available diameters of 3.0, 4.0, 5.0 and 6.0 mm) on which 3 to 6 pairs of bipolar radiopaque electrodes are mounted on its exterior surface. The electrodes transmit low power energy from a radiofrequency generator to the diseased vessel. A switch box measures tissue impedance and adjusts voltage to achieve a constant power that results in acute and local temperature ranges from 50-80°C.

Results
Inflation of the GRST angioplasty balloon to low pressures (2-6 atmospheres) opens the lumen and allows electrical contact at the diseased artery wall. Non-ablative radiofrequency energy (4 Watts) is then applied for 1-4 seconds. Constant power, controlled by the switchbox, results in transient tissue temperatures at the foci of electrode apposition from 50-80°C. In vitro and in vivo analyses of the GRST system show sustained luminal opening (no recoil), restored blood flow, and reduced plaque volume.

Conclusion
The GRST Peripheral Catheter System represents a novel technology for the effective treatment of PAD. With no implant and minimal tension applied to the artery wall, GRST has the potential to obviate sustained inflammation and further damage to the artery wall. Consistently, early clinical results show that GRST results in a sustained luminal opening (no recoil) and reduced plaque volume with no flow-limiting dissections.

Author Disclosure Information:
R.E. Schreiber, Minnow Medical, Inc., C,A; M.F. Hoey, Minnow Medical, Inc., C,E; Minnow Medical, Inc., C,F; M.D. Perry, Minnow Medical, Inc., C,A; Minnow Medical, Inc., C,E; Minnow Medical, Inc., C,F; A.G. Blanck, Minnow Medical, Inc., C,A; Minnow Medical, Inc., C,E; T.A. Steinke, Minnow Medical, Inc., C,A; Minnow Medical, Inc., C,E; S.A. Riddle, Minnow Medical, Inc., C,A; Minnow Medical, Inc., C,E; C.W. Stone, Minnow Medical, Inc., C,A; Minnow Medical, Inc., C,E.