Cath Lab Digest

Abstract

In North America and Europe, over 27 million people suffer from peripheral arterial disease (PAD). Neglected PAD is a leading cause of disability among people aged 50 years and older. The resulting complications are a tremendous cost to society. PAD may produce symptoms from claudication to ulceration, gangrene and limb loss. The severity of presentation depends on the extent of the disease, the degree of stenosis (from minor stenosis to total occlusions) and the presence of collateral circulation.

Overall, chronic total occlusions (CTOs) are more the rule than the exception in PAD. Traditionally, CTOs have been treated surgically, while percutaneous approaches were limited to the treatment of focal occlusions. We present the cases of 4 patients who were successfully treated with the Wildcat device. All of them were difficult cases, with one common denominator: the patients were not good surgical candidates or their surgery had failed. This was the case for 1 patient for whom surgery had to be performed twice. Percutaneous intervention with the Wildcat device can be an excellent alternative strategy for the most difficult CTOs. Further studies and challenging cases are needed to compare the Wildcat with other modalities, including surgery.

VASCULAR DISEASE MANAGEMENT 2010;7:E159–E165

___________________________________________________________

Introduction

In North America and Europe, over 27 million people suffer from peripheral arterial disease (PAD).¹ Neglected PAD is a leading cause of disability among people 50 years and older.^2,3 The resulting complications are a tremendous cost to society. PAD may produce symptoms from claudication to ulceration, gangrene and limb loss. The severity of presentation depends on the extent of the disease, the degree of stenosis (from minor stenosis to total occlusions) and the presence of collateral circulation.

Overall, chronic total occlusions (CTOs) are more the rule than the exception in PAD. Traditionally, CTOs have been surgically treated and percutaneous approaches were limited to the treatment of focal occlusions.⁴

Today, the endovascular specialist has an expanded armamentarium of devices for the treatment of CTOs including the Frontrunner XP CTO (Cordis Corp., Miami Lakes, Florida), with an actuating distal tip that creates a channel through occlusions via blunt microdissection; the PowerWire radiofrequency (RF) guidewire (Baylis Medical Company, Montreal, Quebec, Canada), which works through RF energy delivered through a nitinol core wire with PTFE coating; the Outback LTD Re-Entry Catheter (Cordis), a platinum-coated radiopaque tip re-entry device, which enables re-entry of a guidewire from the subintimal space back into the true lumen via a re-entry cannula and L and T markers; the Pioneer intravascular ultrasound (IVUS)-guided re-entry catheter (Medtronic Vascular, Minneapolis, Minnesota), which uses IVUS to facilitate ease of orientation of the re-entry cannula toward the true lumen; the Crosser Catheter (FlowCardia, Inc., Sunnyvale, California), a rapid-exchange catheter delivering high-frequency vibration for peripheral CTO recanalization; the CiTop wire (Ovalum Ltd., Rehovot, Israel), a guidewire with a dilatable tip; the SafeCross TLX (Spectranetics Corp., Colorado Springs, Colorado) total occlusion crossing system, which is a steerable crossing device designed to cross CTOs in the true lumen with power to ablate an artery wall; and more recently, the Avinger Wildcat 7 Fr Guidewire Support Catheter (Avinger, Inc., Redwood City, California), intended to be used to support steerable guidewires in accessing discrete regions of the peripheral vasculature. The Avinger Wildcat can be used to facilitate placement and exchange of guidewires and other interventional devices, or it may also be used to deliver saline or contrast.

The Avinger Wildcat 6 French (Fr) consists of a distal tip, catheter shaft and a proximal handle that allows for device manipulation and a means for flushing the catheter lumen. The catheter is 135 cm long and is compatible with 0.035 inch guidewires. Two key elements of the device define the treatment modality: the distal tip and the bilateral wedges. Both these elements are visible through fluoroscopy and support the steerable guidewires in accessing the discrete region within the peripheral vasculature.

The Avinger Wildcat Catheter was named after equipment used to drill for oil in Avinger, Texas. Some blockages are severe and difficult to pass through with traditional catheters. The Wildcat is a special kind of catheter used in a minimally invasive endovascular procedure; it acts like a corkscrew, wedging through the blockage. By turning the catheter, the drill spins through the artery, enabling a guidewire to pass through the occluded area.

Femoropopliteal involvement in occlusive PAD is extremely common.⁵ The superficial femoral artery (SFA) is the longest artery in the body. It courses through the muscular portion of the thigh and is subject to torsion and stretching from limb movement. Atherosclerotic disease in the SFA is usually diffuse and the incidence of occlusive and calcific disease is high. Although treatment of CTOs remains challenging and requires patience and knowledge of many devices, clinical success leads to significant improvement in the quality of life and, for some, limb salvage.⁶

We present four challenging CTO cases that were successfully treated with the Wildcat catheter: