Technical Success of Stent Placement via Transradial Approach for Aberrant Right Subclavian Artery Stenosis

Introduction

An aberrant right subclavian artery (ARSA) is a congenital vascular anomaly observed in approximately 0.5% of the population. ¹ Stenotic or occlusive lesions at its origin are extremely rare, and only two cases of stent placement have been reported to date,^2,3 both performed via a femoral artery approach. With advances in endovascular technology, the introduction of protection devices such as balloon guiding catheters has enabled safer procedures. Moreover, the radial artery approach has gained widespread acceptance in the field of neuroendovascular therapy. Here, we present a case of recurrent cerebral infarction caused by stenosis of an ARSA, treated successfully with stenting via the radial artery approach, and discuss its clinical utility and technical advantages.

Case Presentation

A 81-year-old Japanese man presented with dizziness. He was diagnosed with cerebral infarction caused by stenosis at the origin of the ARSA (Figure 1A,B). Despite dual antiplatelet therapy (DAPT), he experienced recurrent cerebral infarctions, and endovascular stenting was planned. Bilateral posterior communicating arteries were of the embryonic type, and severe stenosis of the left subclavian artery was noted, resulting in retrograde flow of the left vertebral artery (VA), indicating subclavian steal. Surgical revascularization was considered; however, catheter-based treatment was ultimately selected. The decision was based on several factors: the concern for recurrence if DAPT had to be discontinued in the setting of frequent recurrent symptoms, the advanced age of the patient, and the difficulty of establishing cardiopulmonary bypass due to bilateral near occlusion of the subclavian arteries with the vertebral arteries located in close proximity and unfavorable hemodynamics with poor collateral circulation between the posterior and anterior systems, which would not ensure adequate perfusion of the posterior circulation. To prevent posterior circulation ischemia during the stenting procedure of the ARSA, stenting of the left subclavian artery was first performed via a left radial artery approach under local anesthesia, with the patient maintained on DAPT. To prevent debris migration from the stenotic lesion into the vertebral artery, blood flow was occluded proximal to the origin of the left VA using an 8-Fr Optimo balloon guiding catheter (Tokai Medical Products, Japan), and an 8 × 27 mm Express stent (Boston Scientific, USA) was deployed. After stent deployment, sufficient blood was aspirated through the Optimo catheter, and the occlusion created by the Optimo was then released. Subsequently, stenting of the severe stenosis of the ARSA was performed via a right radial artery approach. An 8-Fr sheath (Radifocus Introducer II H, Terumo, Japan) was inserted, and an 8-Fr Optimo balloon guiding catheter, a 5-Fr JB-2 type catheter (Medikit, Japan), and a 0.035-inch, 180-cm Radifocus guidewire (Terumo, Japan) were navigated coaxially. To prevent distal migration of debris from the stenotic site, proximal balloon occlusion was performed at the site just proximal to the origin of the right VA using the Optimo balloon guiding catheter. This maneuver enabled clear retrograde visualization up to the aortic arch with contrast injection. The JB-2 type catheter matched well with the anatomy of the origin of the ARSA, facilitating an easy lesion cross (Figure 1C). Predilation was performed using a 5 × 40 mm Mustang balloon catheter (Boston Scientific, USA), followed by deployment of an 8 × 27 mm Express stent (Figure 1D). Before deflation of the guiding balloon, sufficient blood aspiration was performed to collect debris. Stenting of both subclavian arteries was performed in a single session. Because no stent specifically approved for the subclavian artery is available in Japan, an Express stents were implanted with informed consent from the patient. No complications such as cerebral infarction were observed. Postoperatively, transesophageal echocardiography confirmed the absence of plaque protrusion inside the stents. During outpatient follow-up, CTA confirmed no in-stent restenosis and no recurrent ischemic symptoms. Antiplatelet therapy was subsequently de-escalated to single-agent therapy at six months.

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Figure 1.

(A) Maximum Intensity Projection Image of CT Angiography Showing the Aberrant Right Subclavian Artery (Closed Yellow Arrow). Because it Originates Dorsally at a Right Angle to the Aortic Arch, the Stenosis at the Origin is not Visible From this View. The Right Vertebral Artery Originates From the Aberrant Right Subclavian Artery (Open Yellow Arrow). (B) Contrast-Enhanced CT Image Showing Stenosis at the Origin of the Aberrant Right Subclavian Artery. (C) A Catheter was Navigated via the Right Radial Artery Approach. An Optimo Balloon Guiding Catheter (Tokai Medical Products, Japan) was Inflated (Open Blue Arrow), and Contrast Injection Through the JB-2 Type Catheter (Medikit, Tokyo, Japan) with a Judkins Right–like Curve Clearly Delineated the Stenotic Segment up to the Aortic Arch. (D) An 8 × 27 mm Express Stent (Boston Scientific, USA) was Deployed (Closed Green Arrow), Achieving Good Expansion. Visualization of the Full Length of the Stenosis, Extending From the Aortic Arch to the Aberrant Right Subclavian Artery, Facilitated Accurate and Easy Stent Deployment

Discussion

Endovascular treatment is feasible for many patients with subclavian stenosis, and endovascular and surgical treatments generally achieve good outcomes. ⁴ In this case, stenting of the ARSA was performed via a right radial artery approach using a balloon guiding catheter in a patient who continued to experience recurrent cerebral infarctions despite DAPT. No complications occurred, and there was no recurrence thereafter. With regard to the ARSA, it is necessary to understand the hemodynamics and vascular anatomy on a case-by-case basis and to consider appropriate protection strategies for the prevention of cerebral infarction. When subclavian artery stenosis or occlusion is associated with subclavian steal phenomenon, it is reported that restoration of antegrade flow in the vertebral artery can take from 20 seconds to several minutes. ⁵ Therefore, some suggest that distal protection may not be necessary for debris generated at the site of stenosis or occlusion. Additionally, in the ARSA, anomalies in the origin of the right VA are relatively common, with approximately 13.7% arising from the right common carotid artery. ⁶ In such cases, debris generated at the stenotic or occlusive lesion is unlikely to cause cerebral infarction, and protection may not be required. However, in the present case, the right VA originated from the ARSA and demonstrated antegrade flow, making distal protection essential. Furthermore, by occluding the ARSA with the balloon guiding catheter, retrograde contrast injection became possible, allowing clear visualization of the entire segment from the aortic arch to the stenotic lesion.

In previously reported cases using the femoral artery approach.^2,3 The presence of stenotic or occlusive lesions may complicate the selection of the true origin. Moreover, approximately 60% of patients with a ARSA have a bulging structure at the aortic arch known as Kommerell’s diverticulum, which can further hinder catheter selection. ⁷ In such situations, the radial approach offers an advantage, as the catheter can be advanced naturally along the course of the vessel to reach the lesion. Additionally, when severe stenosis or occlusion is present at the aortic origin, and the lesion is long, strong backup support by the guiding catheter is necessary to access the true lumen; achieving sufficient support is difficult with the femoral approach, whereas it can be accomplished with the radial approach. Furthermore, it may become necessary to advance the guidewire beyond the stenotic or occlusive lesion to facilitate catheter navigation, but in such cases, proximal flow control cannot be achieved, increasing the risk of distal embolization by debris. In the present case, by using a balloon guiding system via the right radial artery approach, we were able to achieve easy access, accurate vessel selection, and secure distal protection simultaneously. The characteristics of both radial and femoral approaches are summarized in Table 1. Although the present case demonstrated several advantages of the radial approach as described above, the optimal approach should be selected according to the patient’s condition and vascular anatomy.

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Table 1.

Comparison of Radial and Femoral Approaches for PTA/Stenting of Aberrant Right Subclavian Artery

Aspect	Radial approach	Femoral approach
Access	This approach is minimally invasive. In the presence of subclavian steal, arterial puncture can be difficult owing to decreased blood pressure in the affected upper limb.	Widely applicable, but requires postoperative bed rest.
System	Device selection may be constrained by the vessel diameter.	Allows the use of large-diameter sheaths and guiding catheters, offering a wide range of device options.
Lesion selection	Even in the presence of a Kommerell’s diverticulum, the lesion can be reached in a relatively straightforward manner by following the vessel lumen.	Catheter selection with a microcatheter may be challenging because of the influence of aortic flow. In ARSA occlusion or severe stenosis, identification of the true lumen is difficult. Anatomical orientation may be unfamiliar, and particularly in the setting of a Kommerell’s diverticulum, the origin of the ARSA can be difficult to identify.
Lesion crossing	Provides strong proximal support, allowing wires and catheters to advance even through long occlusive lesions.	Proximal support is weak, making it difficult to advance devices through the true lumen.
Protection	Proximal protection can be achieved by inflating a guiding balloon proximal to the vertebral artery origin, or by balloon occlusion of the vertebral artery itself, thereby preventing distal embolization.	Proximal protection is difficult to secure, and the risk of cerebral embolism remains.

Because the ARSA joins the aortic arch dorsally, securing an optimal deployment angle for stenting was a concern. However, it was possible to create a single view perpendicular to the aortic arch, allowing simultaneous visualization of the aortic origin, the stenotic segment, the full length of the stent, and the entire landing zone within a single angle, which enabled safe and precise stent deployment. The radial artery approach appears to be an effective and promising option for stenting procedures targeting stenosis or occlusion at the origin of the ARSA.