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Anand Prasad, MD, an 18-year veteran of vascular and endovascular medicine with a particular interest in peripheral arterial disease (PAD) in patients with chronic kidney disease (CKD), explores the deliverability of the Shockwave E8 catheter below the knee in patients with advanced disease.
Below-the-knee (BTK) intervention in patients with chronic limb-threatening ischemia (CLTI) represents a challenging area in our field. The length, calcification and smaller size of tibial vessels, coupled with patient comorbidities such as diabetes and CKD, and the consequences of procedural failure, all converge in these patients.1,2 Traditionally, plaque modification with atherectomy devices has been the primary mode to address vessel calcium. Although effective in many cases, atherectomy carries a risk of distal embolization, vessel perforation, and a variable impact on deep and superficial calcium, depending on the specific device used.
Shockwave Medical’s introduction of intravascular lithotripsy (IVL) into the endovascular field has been revolutionary for the treatment of calcium. In my own practice, the use of IVL has provided multiple benefits, including replacing atherectomy for many cases, reducing flow-limiting dissections, and improving vessel preparation prior to adjunctive therapies.
Most recently, our center has used the newest iteration of Shockwave’s IVL family of peripheral catheters extensively: the Shockwave E8 catheter. The Shockwave E8 provides a broad range of IVL sizes, which span utility above and below the knee. Key features include diameters of 2.5–6.0mm, 80mm balloon length with evenly spaced emitters, 150cm working length for distal vessel reach, 400 pulses available at 2Hz (two pulses per second). As many operators use lower-profile access, the smaller balloon sizes, 2.5–4.0mm, are compatible with 5F sheaths. In my experience, the versatility of these Shockwave E8 features can replace the use for Shockwave S4 and Shockwave M5+ catheters in many vessel sizes.
A key challenge with IVL therapy in the BTK circulation has been deliverability. To date, pre-IVL vessel preparation with gentle balloon dilation or use of atherectomy were the primary means to help advance the Shockwave devices. Shockwave E8 has been easier to deliver, despite the longer length relative to the Shockwave S4, in large part due to more extensive (45cm) hydrophilic coating, coupled with a novel tapered tip. These latter features have been particularly helpful to me when treating chronic total occlusions (CTO), as well as distal tibial lesions. The following case highlights many of these capabilities of the Shockwave E8 in CLTI patients.
Case report
Introduction
A 75-year-old female patient with diabetes and end-stage kidney disease (ESKD) presented with progressive right second toe swelling ulceration with gangrene and rest pain (Figure 1). There was extensive osteomyelitis and underlying tissue injury which required a planned amputation of the second toe. We were consulted prior to amputation for angiography, which demonstrated patent inflow vessels but severe BTK tibial disease. The baseline angiogram is shown in Figure 2. There was no inline flow to the foot, with occlusion of the anterior tibial, posterior tibial and peroneal arteries (Figure 2a). There was reconstitution of the peroneal artery, with partial filling of the posterior circulation via the posterior communicating artery. There was reconstitution of the anterior circulation with a visible small dorsalis pedis artery (Figure 2b).
Procedural overview
Given the angiosome of the tissue loss, we elected to pursue opening the anterior tibial CTO. Access with a 5F, 70cm sheath was used from a contralateral femoral approach. Using a 0.014” microcatheter and wire escalation, we were able to cross into the true distal lumen of the distal anterior tibial circulation using a 12-gram tipped guidewire (Figure 3a). A 2.5mm Shockwave E8 was used for multiple treatments along the entire length of the CTO segment (Figures 3b, 3c). Post IVL therapy, angiography showed brisk flow through the anterior tibial and into the distal anterior circulation of the foot (Figures 4a-c). This improvement in circulation allowed for this patient to undergo her planned second toe amputation with primary close (Figure 4d).
Conclusion
The key takeaway points for this case were the deliverability of the Shockwave E8 and the ability to treat longer segments versus the Shockwave S4. In addition, in many cases the Shockwave E8 can serve as the primary or final therapy without the need for additional angioplasty. This catheter continues the evolution of treatment options for patients with BTK disease.
References
- Feraresl R, et al. J Cardiovasc Surg. 2018 Oct;59(5):655-664
- Mustapha JA, et al. Circ CV interventions. 2016;9e003468
Anand Prasad is a professor of medicine and director of interventional cardiology at UT Health San Antonio and University Health in San Antonio, Texas. He is a paid consultant of Shockwave Medical. The views expressed are those of the author and not necessarily those of Shockwave Medical.
Peripheral Safety Information In the United States: Rx only. Indications for Use—The Shockwave Medical Intravascular Lithotripsy (IVL) System is intended for lithotripsy-enhanced balloon dilatation of lesions, including calcified lesions, in the peripheral vasculature, including the iliac, femoral, ilio-femoral, popliteal, infra-popliteal, and renal arteries. Not for use in the coronary, carotid or cerebral vasculature Contraindications—Do not use if unable to pass 0.014” (M5, M5+, S4, E8) or 0.018” (L6) guidewire across the lesion-Not intended for treatment of in-stent restenosis or in coronary, carotid, or cerebrovascular arteries. Warnings—Only to be used by physicians who are familiar with interventional vascular procedures—Physicians must be trained prior to use of the device— Use the generator in accordance with recommended settings as stated in the Operator’s Manual. Precautions—use only the recommended balloon inflation medium—Appropriate anticoagulant therapy should be administered by the physician— Decision regarding use of distal protection should be made based on physician assessment of treatment lesion morphology. Adverse effects–Possible adverse effects consistent with standard angioplasty include–Access site complications – Allergy to contrast or blood thinner– Arterial bypass surgery—Bleeding complications—Death— Fracture of guidewire or device—Hypertension/Hypotension— Infection/sepsis—Placement of a stent—renal failure—Shock/ pulmonary edema—target vessel stenosis or occlusion— Vascular complications. Risks unique to the device and its use—Allergy to catheter material(s)— Device malfunction or failure—Excess heat at target site. Prior to use, please reference the Instructions for Use for more information on indications, contraindications, warnings, precautions and adverse events. www.shockwavemedical.com/IFU. SPL-73445 Rev. A
