Successful Treatment of Chronic Total Occlusions with the Wildcat Catheter

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

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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:

Case 1. A 73-year-old female patient with a longstanding history of insulin-dependent type II diabetes mellitus, hypertension and dyslipidemia had chronic non-healing wounds in the left lower extremity with two prior failed femoro-popliteal bypasses in the left lower extremity, status post amputation of the first ray in the left foot performed 2 months previously. She was admitted to the hospital due to her non-healing surgical wound (post amputation) and an ulcer in the left heel despite aggressive wound care. A TCPO2 (transcutaneous partial pressure of oxygen) performed in the left lower extremity was 13 mmHg, with a reference in the thorax of 38 mmHg. Her dorsalis pedis and posterior tibialis pulses were nonpalpable in the left lower extremity. The patient was taken to the catheterization laboratory and underwent abdominal aortography and selective angiography of the left lower extremity which showed a total occlusion of the left SFA with reconstitution in the distal popliteal artery. She was not considered a good candidate for further surgical procedures due to prior failure of two femoro-popliteal bypass procedures. With the diagnosis of limb-threatening ischemia, attempts at intervention of the 100% CTO of the left SFA were performed initially using a contralateral approach. Several tools were used; initially, a Frontrunner CTO catheter was advanced to the proximal left SFA and to the mid-to-distal vessel. However, the distal SFA could not be crossed. A Crosser device was also used, but without success. In a second attempt, the patient was taken back to the catheterization laboratory; access was obtained in an antegrade fashion in the left common femoral artery (Figure 3), but again, the SFA could not be crossed despite several attempts with several wires including a ChoICE PT Extra-Support (Boston Scientific), a Confianza wire (Abbott Vascular) and a Glidewire (Terumo Medical Corp., Somerset, New Jersey), as well as a Wildcat catheter. As a last resource, the left dorsalis pedis artery was accessed in an attempt to cross the CTO of the left SFA in a retrograde manner. Due to the favorable size of the distal anterior tibial artery, a 6 Fr sheath was placed in the proximal dorsalis pedis and advanced to the distal anterior tibial artery. Subsequently, with the help of a Wildcat catheter, a Glidewire was used to cross the left SFA CTO (Figure 4). The wire was snared through the left femoral sheath, then a QuickCross (Spectranetics) was exchanged for a ChoICE PT, and finally, atherectomy, angioplasty and stenting of the SFA were performed with excellent flow achieved above and below the knee (Figures 5a and b).

Case 2. An 83-year-old male with a history of coronary artery disease (CAD) and previous coronary artery bypass graft surgery (CABG), as well as a history of type II diabetes mellitus, hypertension and hypercholesterolemia, was admitted to the hospital due to lifestyle-limiting claudication despite treatment with cilostazol and an exercise rehabilitation program. His symptoms were more severe in the left lower extremity. The patient had an abdominal aortogram and a bilateral lower-extremity angiogram that showed 100% stenosis of the left SFA (Figure 6) and 99% stenosis of the right SFA, as well as high-grade stenosis of the trifurcation vessels bilaterally. In a second procedure, an antegrade approach was used in the left common femoral artery and the total occlusion of the left SFA was successfully crossed with the Wildcat catheter (Figure 7). This procedure was followed by atherectomy of the SFA with an LXM SilverHawk atherectomy device (ev3, Inc., Plymouth, Minnesota) (Figure 8). Further intervention was done to the arterial circulation below the knee including atherectomy of the tibioperoneal trunk with an EXL SilverHawk atherectomy device and angioplasty of the dorsalis pedis using a 2.0 by 80 mm Nanocross balloon (ev3, Inc.).

Case 3. A 71-year-old male with severe PAD, status post bilateral femoro-popliteal bypass with re-do bypass of the left lower extremity and multiple peripheral percutaneous interventions (PCIs), presented to the clinic with disabling claudication. His past medical history includes hypertension, dyslipidemia, diabetes, chronic kidney disease, status post multiple PCIs and carotid interventions, congestive heart failure (New York Heart Association Class III), chronic obstructive pulmonary disease, and arrhythmia treated with ablation and biventricular implantable cardioverter defibrillator placement. Recently, the patient developed resting pain and disabling claudication of left lower extremity, Doppler surveillance revealed occlusion of the re-do bypass graft. A diagnostic angiogram with runoffs showed diffuse PAD involving both lower extremities with complete occlusion of the left distal common femoral artery at the side of proximal anastomosis of a failed femoro-popliteal graft (Figure 9). The SFA was completely occluded throughout, and the only vessel reconstituted via collaterals was the profunda, which further collateralized the distal popliteal artery and runoff vessels. The first attempt to treat the CTO with various techniques was unsuccessful. In our second attempt, we chose the Wildcat catheter. A 7 Fr sheath was inserted via the right femoral approach up and over the bifurcation of the aorta and positioned in the left external iliac artery. Guiding angiograms were taken, demonstrating complete occlusion of the distal common femoral artery and ostial profunda. We advanced the Wildcat catheter with counter clockwise rotation towards the profunda (Figure 10). After pulling back the device, the wire crossed the CTO without difficulty. Subsequently, angioplasty was performed using an Admiral Xtreme 5.0 x 60 mm balloon (ev3, Inc.). CTO was reduced to less than 10% residual stenosis (Figure 11). The patient immediately reported warming of the left lower extremity. Follow-up angiograms demonstrated very brisk flow to the profunda and distal runoff vessels. The patient left our center 4 hours post procedure with resolution of his resting pain.

Case 4. A 77-year-old female with disabling claudication and status post left below-the-knee amputation. had developed a painful sore of the stump. Her other medical history included hypertension, dyslipidemia, diabetes and coronary artery disease. She was found to have a grossly abnormal pulse volume reording study (PVR) and angiography revealed a 100% left SFA CTO (Figure 12). With the support of the Wildcat catheter, we were able to create the channel in the plaque (Figure 13). A Confianza wire was advanced through the lumen of the wildcat catheter. Then, using 4.5 x 40 mm Sterling angioplasty balloon (Boston Scientific), antegrade flow was restored. The entire area was stented with a 6.0 x 80 mm LifeStent FlexStar stent (Bard Peripheral Vascular, Inc., Tempe, Arizona). The CTO was reduced to Conclusion Recent advances in endovascular technology, coupled with the perception of associated lower morbidity and mortality rates, have made the percutaneous treatment of severe lower-extremity ischemia more attractive in the past few years.⁷ Patients with critical limb ischemia are at risk for both limb loss and early mortality, but the improvement of endovascular devices and techniques have diminished the necessity of open surgical procedures.⁸ Treatment of CTOs is a challenge for all clinicians who devote significant time to improving quality of life and limb salvage. Research has shown that the larger the series of CTO treatment cases, the better the outcomes, with success rates varying between 70–80%. Surgical treatment of CTOs has well-known limitations, particularly in terms of conduit availability in post-CABG patients, poor durability of the conduit as in cadaveric veins and the poor distal target vessels due to diffuse atherosclerosis that almost invariably presents in these patients. Particular problems related to surgery and anesthesia such as being bed-ridden increase the risk of deep vein thrombosis and pulmonary emboli. Non-healing surgical wounds, especially in diabetics, are not uncommon. Newer technology for the treatment of CTOs and the relentless dedication of the interventionist have improved patient outcomes. We report four cases that were successfully treated with the Wildcat device. All of them were challenging cases with one common denominator: surgery was not a good option or, when performed, failed early post surgery as in 1 patient in whom surgery was performed twice (Case 1). 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. However, it is the impression of the authors, based on our experience with the treatment of CTOs, that the use of the Wildcat catheter may reduce the overall procedure time compared to other CTO devices on the market and may allow higher success rates.

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From the *Texas Tech Health Science Center University, El Paso, Texas (Assistant Professor), and Division of Interventional Cardiology, Del Sol Medical Center; £Assistant Professor, Texas Tech Health Science Center University, El Paso, Texas; §Division of Interventional Cardiology, Del Sol Medical Center; Assistant Professor, Texas Tech Health Science Center University, El Paso, Texas; ∞San Antonio Endovascular and Heart Institute, San Antonio, Texas; Associate Professor of Medicine at the University of Texas Health Science Center, San Antonio, Texas. The authors report no conflicts of interest regarding the content herein. Manuscript submitted November 16, 2009, provisional acceptance given January 21, 2010, final version accepted January 26, 2010. Address for correspondence: Oscar C. Munoz, MD, Heart and Vascular Partners, 11551 Cedar Oak Drive, El Paso, TX 79936. E-mail: omunoz1968@hotmail.com