Cath Lab Digest - September 2007 - (Page 16)

16 CLINICAL REVIEW SEPTEMBER 2007 Figure 3. A 63-year-old male with an ischemic cardiomyopathy and mitral regurgitation was evaluated for right rest foot pain and a non-healing ulceration. He had a right ABI of 0.46 and a magnetic resonance angiography demonstrated a long occlusion of the superficial femoral artery (SFA), with reconstitution of the above-the-knee popliteal artery and an occluded posterior tibial artery. The intervention was performed via the contralateral femoral artery approach, using a 7-Fr crossover sheath. Angiography confirmed the SFA occlusion and did not demonstrate significant vascular calcification (a). Subintimal passage of the wire and glide catheter progressed to the distal edge of the CTO, but the true lumen could not be reentered with standard guidewire techniques. The Outback reentry device was advanced subintimally over an .014” guidewire approximately 1 cm beyond the distal edge of the occlusion and the device positioned towards the artery by aligning the device marker (b). An orthogonal view, used to confirm the device marker, is superimposed on the vessel, confirming the needle is positioned towards the lumen (c). The wire is withdrawn into the catheter and then the nitinol needle is deployed into the vessel. The wire is readvanced through the needle into the distal true lumen (d). The procedure is then completed with balloon angioplasty and placement of selfexpanding stents (e). laser is its ability to ablate plaque and thrombus and therefore, minimize embolic complications. The laser has also been shown to reduce platelet aggregation.26 Excimer laser atherectomy, of both peripheral and coronary arteries, has been used in clinical practice and has several potential uses in peripheral CTOs. For lesions that cannot be crossed with conventional wires, a wireless laser-assisted technique can be used. In this technique, the laser is used to create a channel and then the wire and laser are advanced in a stepwise fashion.27 For long CTOs, the laser may be used to identify critical segments requiring further PTA or stenting. The safety and efficacy of excimer laser-assisted angioplasty for peripheral CTOs was investigated in a series of 318 consecutive patients with 411 SFA CTOs, averaging 19.4 ± 6.0 cm in length. The initial attempt to cross the occlusion was successful in 83.2% of limbs. A secondary attempt increased the technical success rate to 90.5%. Complications included acute closure in 1.0%, perforation in 2.2%, and distal embolization in 3.9% of limbs.28 The excimer laser has also been used successfully for patients with occlusive disease and CLI.29 Thrombolytic Therapy Although shown to be effective and routinely used for acute and subacute arterial and graft occlusions, thrombolytic therapy is rarely used for CTOs because of the availability of multiple alternative techniques, bleeding risks and the inconvenience of local intra-arterial infusions and questionable effectiveness. Although thrombolyic therapy has been used for peripheral CTOs for over 30 years,30,31 it is more successful for subacute than chronic occlusions, shorter occlusions, and lesions in larger arteries, such as the iliac.32,33 Using thrombolytic therapy as an adjunct to PTA may increase procedural success by reducing the thrombotic component of the CTO. Local thrombolytic infusion, however, may require continuation for several days to achieve success. At the least, thrombolytic therapy should be considered part of the CTO armamentarium and may be useful when other strategies are ineffective.34 of perforation. The ultrasound-guided device may be preferable in this circumstance and covered stents should be readily available. Alternative Crossing Approaches There are CTOs that have characteristics that are not favorable for the standard wire or subintimal approach. They include occlusions that are flush with a major sidebranch or collateral supply, such as the ostial SFA, vessels with heavy calcification, those with diffuse disease in the reconstituted segment, and those involving segments, such as the common femoral or popliteal artery, where stenting is best avoided. In these cases, other device options can be considered and are discussed below. Blunt microdissection. The Frontrunner catheter (Cordis Corp.) is a blunt microdissection device that can penetrate the hard caps of fibrocalcific plaques and is approved for both coronary and peripheral CTOs. The device is advanced into the occlusion and the actuating jaws are opened to create plaque fracture planes. The catheter is slightly withdrawn and the jaws are allowed to close. Then, the catheter is advanced further into the occlusion. If successful, a .014” wire can ultimately be passed into the distal lumen. The ability of this device to increase overall success rates for CTO cases is unclear, but some cases of success following guidewire failure have been reported.23 Radiofrequency ablation. The SafeCross wire (IntraLuminal Therapeutics, Menlo Park, CA) combines a forwardlooking optical coherence reflectometer with radiofrequency energy that is delivered from the wire tip. The nearinfrared sensor can detect differences in the vessel wall, plaque and lumen, based on tissue characteristics. Green and red signals identify an intraluminal versus near endoluminal position, respectively, and radiofrequency is delivered if the reflective signal is green. Theoretically, this capability allows the wire to remain intraluminal, which may be desired for occlusions near large collateral vessels or that lead to diffusely diseased vessels. Registries have shown promising results with the device. In 75 lower-extremity CTOs that failed guidewire attempts, 76% were successfully crossed with the device with no clinical perforations or distal embolizations.24 In another small series, the Safe-Cross wire was successfully used in 18 lower-extremity CTOs with a mean length of 22.4 cm that previously failed with conventional guidewires.25 Excimer laser. The 308-mm excimer laser (Spectranetics) ablates tissue without thermal injury by utilizing fiber-optic catheters to deliver ultraviolet energy in short pulse durations. A theoretical advantage of the Ultrasound Therapy In the near future, a new CTO device that utilizes high-frequency mechanical vibration to penetrate

Table of Contents Feed for the Digital Edition of Cath Lab Digest - September 2007

St. Dominic Hospital The Genous Bio-engineered R Stent Percutaneous Treatment of Peripheral Arterial Chronic Total Occlusions: Device Options and Clinical Outcomes Contents Clinical Editor’s Corner Percutaneous Revascularization of Peripheral Chronic Total Occlusion — Which Patients, Why, and How? Myocardial Infarction and Syncope: A Manifestation of the “Raynaud-Prinzmetal Syndrome”? Essential Technical Components of the Transradial Approach If You Build It, Will They Come? Evidence-Based Medicine with Drug-Eluting Stents Back to School: The Value of Education in Cardiovascular Services The ACVP Standards and Competencies: Are You Using Them Effectively? What Do You Think? My Experience with Fibromuscular Dysplasia and Stroke A Brief Review of Fibromuscular Dysplasia Letter to the Editor A Look at On-the-Job Training: Perceptions, Reality and Our Profession Doing the Wave: Inventory Management with RFID The Ten-Minute Interview with… Paul Pinsker, RCIS CLD’s Annual Salary Survey Harrisburg Area Community College Volunteer Survey CEU Education Center SICP* Section Ask the Clinical Instructor: A Q&A Column for Those New to the Cath Lab Clinical & Industry News

Cath Lab Digest - September 2007

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