Intravascular lithotripsy angioplasty for treatment of atherosclerotic coral-reef occlusion of the infrarenal aorta and its bifurcation

In the present report, we have described the use of intravascular lithotripsy angioplasty for heavily calcified occlusions of the infrarenal aorta and its bifurcation in two patients. In the first patient, two lithotripsy balloons in kissing conformation were simultaneously used to allow for dilatation of the distal aorta and its bifurcation with preservation of accessory renal artery patency, followed by stenting of the iliac arteries. For the second patient, the infrarenal aorta occlusion was first treated with a single lithotripsy balloon, followed by covered stenting. Intravascular lithotripsy could represent a valid endovascular adjunct to optimize outcomes in the treatment of coral reef aortas and aortic bifurcation occlusion.

Severe aortoiliac obstructive disease, including type D Trans-Atlantic Inter-Society Consensus II lesions, has been traditionally treated with aortobifemoral bypass, although associated with considerable morbidity and mortality. 1,2 More recently, endovascular treatment has emerged as a first-line approach for complex lesions involving the entire infrarenal aorta or its bifurcation.
Nevertheless, the presence of highly calcified vessels can represent a considerable challenge for endovascular repair, and the risk of life-threatening complications, such as arterial rupture or dissection, 3-6 must be considered. In addition, target lesion patency can be affected by the inability to achieve adequate intraoperative dilatation or lesion recoil. The use of covered stents can improve the patency rates. However, coverage of important side vessels and inadequate stent radial forces have remained problematic.
The Shockwave IVL (intravascular lithotripsy) device (Shockwave Medical, Inc, Santa Clara, CA) is a novel endovascular tool that uses an angioplasty balloon to deliver acoustic shockwaves to the arterial wall, creating microfractures in calcified plaques. The device is intended for the treatment of highly calcified lesions. By making the vessel more compliant, IVL can be used for vessel preparation or treatment, reducing the risk of wall rupture. 7 It has been successfully used in the treatment of iliac obstructive disease. However, its application for disease extending into the aortic bifurcation and infrarenal aorta, especially in presence of complete occlusions, has not yet been described.
We have reported the case of two patients who had presented with extensive aortoiliac atherosclerotic disease characterized by heavily calcified occlusions involving the infrarenal aorta and its bifurcation. The patients provided written informed consent for the intervention and the report of their case details and imaging studies.

Patient 2.
A 69-year-old man had been referred for lifelimiting intermittent claudication that occurred after walking 65 ft, no palpable femoral pulses, and a monophasic waveform at both common femoral arteries. His medical history included hypertension, dyslipidemia, diabetes mellitus, and previous carotid endarterectomy. CTA revealed extensive aortoiliac obstructive disease with complete "coral reef" occlusion of the mid-infrarenal aorta and bilateral common iliac artery occlusion (Fig 3). The aortic diameter was 12 mm, and the diameter of the iliac arteries was 8 mm.
After bilateral percutaneous femoral access, the infrarenal aorta was predilated with a standard 5-mm balloon. Next, a 6.5 Â 60-mm Shockwave M5þ balloon was advanced and progressively inflated to 6 atm during a 10-cycle period. An additional 10 cycles were delivered for aortic preparation using an 8 Â 60-mm Shockwave M5þ balloon. To allow for adequate aortic dilatation from 8 mm to its 12-mm diameter, covered endovascular reconstruction of aortic bifurcation was performed, using an 11-mm Viabahn VBX stent (W.L. Gore & Associates, Flagstaff, AZ) expanded to 12 mm with a semicompliant balloon proximally. 8 Completion aortography confirmed patency of the stented aorta and iliac axes, with no sign of stent recoiling or restenosis, and the duplex ultrasound scan showed a triphasic femoral waveform (Fig 4). At 12 months after the intervention, the patient had had no symptom recurrence. The postoperative CTA is shown in Fig 5. DISCUSSION Endovascular treatment of heavily calcified lesions of the abdominal aorta and its bifurcation has been hampered by the risk of arterial perforation or flowlimiting dissection, and the clinical outcomes have been affected by inadequate dilatation and/or early stent recoiling, leading to loss of patency. Thus, IVL might have an important role in providing effective calcium microfracture without the risk of rupture. 9 IVL has been used for the treatment of coronary, iliac, and infrainguinal artery disease. 10 However, the reported experience in the aortoiliac segment is limited. In the case of calcified iliac arteries, IVL has been used to provide safe vessel preparation before stent placement, with good procedural success and low rates of residual stenosis and complications. 11 Also, the use of IVL, with or without associated stenting, has been proved useful to enable large-bore transfemoral access (ie, during transfemoral aortic valve implantation), with a reported reduction in access-related complications. 12,13 To the best of our knowledge, we have described the first use of IVL for the treatment of the infrarenal aorta and aortic bifurcation. In our experience, in cases of total occlusion, predilatation with a plain angioplasty balloon might be required to allow for safe IVL balloon advancement, avoiding the risk of rupture. The use of two kissing IVL balloons, each one attached to a dedicated generator, could be advantageous for the treatment of the aortic bifurcation to avoid the risk of contralateral plaque shift during dilatation. The use of IVL by itself might be sufficient to achieve hemodynamic success and can be considered as a standalone treatment for selected cases. However, stabilization of the result through the deployment of covered stents might improve the durability.
In clinical practice, the use of IVL might be limited by its costs and availability, and, in our experience, its use has been limited to highly selected patients with heavily calcified aortoiliac obstructive lesions at risk of rupture during the procedure.