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J Neurosurg Case Lessons
J Neurosurg Case Lessons
J Neurosurg Case Lessons
Journal of Neurosurgery: Case Lessons
2694-1902
American Association of Neurological Surgeons

39284234
10.3171/CASE24383
CASE24383
SpineSpineCervicalCervicalVascular-DisordersVascular DisordersCase Lesson
Covered stent deployment for a recurrent cervical internal carotid artery aneurysm referencing angioscopy: illustrative case
Hayami Hiromichi MD 1
Fukutome Kenji MD, PhD 1
Aketa Shuta MD, PhD 1
Fukumori Junji MD 1
Mitsui Takaaki MD 1
Shiraishi Yuki MD 1
Matsuoka Ryuta MD, PhD 1
Mori Naoki MD, PhD 2
Tei Rinsei MD, PhD 1
Shin Yasushi MD, PhD 1
Motoyama Yasushi MD, PhD 1
1 Department of Neurosurgery, Osaka Police Hospital, Osaka, Japan
2 Cardiovascular Division, Osaka Police Hospital, Osaka, Japan
Correspondence Kenji Fukutome: Osaka Police Hospital, Osaka, Japan. kenjifukutome82@gmail.com.
INCLUDE WHEN CITING Published September 16, 2024; DOI: 10.3171/CASE24383.

Disclosures The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper.

16 9 2024
16 9 2024
8 12 CASE2438318 6 2024
19 7 2024
© 2024 the authors
2024
the authors
https://creativecommons.org/licenses/by-nc-nd/4.0/ CC BY-NC-ND 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/)

BACKGROUND

Extracranial carotid artery aneurysms (ECAAs) are rare, and treatment guidelines are lacking. Few reports on endovascular treatments performed for ECAAs exist.

OBSERVATIONS

A 73-year-old woman with a left giant cervical internal carotid artery aneurysm was treated with overlapping closed-cell stents. The aneurysm regrew 1 year after the treatment, and then a covered stent was deployed. Angioscopy was performed to confirm neointimal development to determine the appropriate stent position before the retreatment, and it revealed that the stent struts were embedded in thick neointima for the most part but that the neointima was thin around the aneurysm neck. Multiple holes connecting to the aneurysm were observed between the stent struts. A covered stent overlapped inside the closed-cell stents, and blood flow into the aneurysm completely disappeared.

LESSONS

When deploying the covered stent for recurrent aneurysms, angioscopy is useful for confirming neointimal development and determining the appropriate stent length and position. Angioscopic observations suggest that using stents with a higher mesh density and smaller pore size can reduce the neck hole size of the aneurysm and may achieve complete occlusion of the aneurysm.

https://thejns.org/doi/10.3171/CASE24383

extracranial carotid artery aneurysm
covered stent
angioscopy
case report
ABBREVIATIONS

ECAA = extracranial carotid artery aneurysm
ICA = internal carotid artery
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pmcExtracranial carotid artery aneurysms (ECAAs) are rare, and treatment guidelines are lacking.1–4 The recurrence of ECAA posttreatment is even rarer,5 and there are no reports on deploying stents to ECAAs with the aid of angioscopy. Here, we present a case in which a recurrent giant cervical internal carotid artery (ICA) aneurysm, which had been treated with overlapping carotid artery stenting, was treated with covered stent placement, and angioscopy was useful in deciding the appropriate stent position.

Illustrative Case

A 73-year-old woman presented with transient right-sided blindness. She had no history of trauma, infection, tumor, radiotherapy, or surgical intervention in the neck. Magnetic resonance imaging did not reveal ischemic lesions or intracranial hemorrhage. Angiography showed a giant cervical left ICA aneurysm at the vertebral height of C1 and distal ICA stenosis, raising suspicion of a hemodynamic transient ischemic attack. She was treated with overlap stenting using two Carotid Wallstents (Boston Scientific; Fig. 1). Blood flow into the aneurysm decreased and ICA stenosis improved. There were no changes on follow-up angiography 4 months after treatment. FIG. 1. Preinterventional left carotid angiogram showing a 28.9 × 24.0 × 20.0–mm cervical ICA aneurysm and distal ICA stenosis (A). Blood flow into the aneurysm decreased after the Carotid Wallstent deployment (B).

The patient complained of a scratchy throat 1 year after the treatment, and magnetic resonance imaging showed aneurysm regrowth. Angiography revealed an inflow jet inside the narrow-necked aneurysm from the ICA (Fig. 2A, Video 1), and the insertion of a covered stent was planned. FIG. 2. Left carotid angiograms showing the aneurysm regrowth (A) and VIABAHN overlaps inside the Wallstent (B). No blood flow into the aneurysm was observed after the retreatment (C).

VIDEO 1. Clip of an angiography study showing an inflow jet inside the aneurysm. Click here to view.

The length of the covered stent should be as short as possible to avoid endoleak or stent thrombosis.6 However, when the neointimal coverage of the Carotid Wallstent strut is not enough, deploying a shorter stent can lead to poor stent adherence, and deploying a longer stent within the area where neointima is sufficiently covering is needed. Therefore, it is important to confirm the neointimal development and determine the appropriate stent length and position. The lesion could not be observed on preoperative carotid artery ultrasonography because it was in a high position.

Operation

Clopidogrel (75 mg/day) was administered 2 weeks before the operation and added to the originally administered 100 mg/day aspirin as antiplatelet medication. The operation was performed with the patient under local anesthesia. First, a 9-Fr sheath was inserted into the right femoral artery, and a 9-Fr Optimo catheter (Tokai Medical Products) was guided to the left ICA. On angiography, a space between the vessel wall and the stent, possibly indicative of neointima, was observed proximal and distal to the aneurysm. However, it was difficult to confirm whether neointima had formed around the aneurysm neck due to the jet flow into the aneurysm. Neointima was also not detected on intravascular ultrasound; thus, angioscopy was performed to accurately evaluate the extent of neointima formation at the previous stent placement site under direct vision before retreatment. A VISIBLE angioscope (Intertec Medicals) was inserted through the 4-Fr catheter placed inside the Optimo catheter and carefully withdrawn from the distal end to the proximal end of the Carotid Wallstent. Angioscopy revealed that the Carotid Wallstent struts were embedded in thick neointima for the most part (Fig. 3A); however, the neointima was thin (neointimal coverage grade 1: transparent stent struts with dull light reflection) around the aneurysm neck,7 and multiple holes connected to the aneurysm were observed between the stent struts (Fig. 3B, Video 2). According to these results, the short VIABAHN device (7 mm × 25 mm, Gore) was placed to overlap inside the Carotid Wallstent. Finally, blood flow into the aneurysm completely ceased (Fig. 2B and C), and no embolic complications were shown on angiography of the left ICA. FIG. 3. Angioscopy performed before the retreatment shows that Carotid Wallstent struts were embedded in thick neointima for the most part (A), and multiple holes (white arrowheads, B) connected to the aneurysm are observed between the stent struts (black arrowheads).

VIDEO 2. Clip of an angioscopy study showing neointimal coverage and multiple holes connected to the aneurysm between the stent struts. Click here to view.

The patient did not have new neurological symptoms. The throat discomfort improved the day after treatment, and magnetic resonance imaging showed no ischemic lesions. Two months after treatment, follow-up computed tomography angiography showed complete occlusion of the aneurysm; in-stent stenosis was not observed (Fig. 4). FIG. 4. Computed tomography angiography 2 months after the retreatment shows complete occlusion of the aneurysm (A), and in-stent stenosis is not demonstrated (B).

Patient Informed Consent

The necessary patient informed consent was obtained in this study.

Discussion

Observations

ECAAs are uncommon, accounting for 0.4%–4% of all peripheral artery aneurysms,1 and reports on the recurrence of ECAA are even rarer.5 Atherosclerosis and pseudoaneurysm formation are the leading causes of ECAAs.8 Other causes include infection, fibromuscular dysplasia, connective tissue disorders, radiotherapy, or trauma.3 If untreated, ECAAs are associated with an increased risk of transient ischemic attack and ischemic stroke; however, evidence-based ECAA treatment guidelines are lacking.1 Endovascular treatment for ECAAs includes stent-assisted coil embolization, carotid artery stent placement, covered stent placement, and flow diverter placement. In the present case, overlapping Carotid Wallstents were deployed during initial treatment with the aim of generating a flow diversion effect; however, the aneurysm recurred. Coil embolization for large aneurysms carries a high risk of recurrence,9 intraoperative aneurysm rupture, and worsening of symptoms due to the mass effect. Additionally, since the aneurysm recurred after overlapping stents, it was possible that the same treatment would also have a high likelihood of recurrence. Flow diverter placement was unsuitable because the diameter of the ICA at the site scheduled for stent placement exceeded 5 mm; therefore, a covered stent was deployed to securely block blood flow into the aneurysm. No perioperative complications were observed, and follow-up imaging showed complete occlusion of the aneurysm.

Covered stent malposition to the parent vessel, especially around the aneurysm neck, has a risk of endoleak.10 Vascular anatomy correlation (ICA tortuosity), operation technique correlation, and poor stent adherence are also common reasons for an endoleak.11 An endoleak causes inadequate neointimal coverage of the stent struts, activation of platelet function, and very late stent thrombosis, in addition to aneurysm regrowth.11 To avoid an endoleak, it is desirable to place a short covered stent in the appropriate position. In this case, there was little tortuosity of the target parent vessel, and the deviation of the vessel diameter was not significant. However, the risk of endoleak is thought to be high when the covered stent deploys within the area where the Carotid Wallstent strut is exposed (not covered with enough neointimal coverage). In cases where in-stent neointimal formation has not developed sufficiently, the long covered stent needs to be deployed from the normal parent artery to the normal parent artery. Thus, it was necessary to confirm the neointima within the Carotid Wallstent.

There is no established consensus on when the neointima forms after carotid artery stenting. Sufficient neointima formation within the previous stent reduces the likelihood of poor stent adherence at the retreatment of covered stent deployment. Although computed tomography, magnetic resonance imaging, and digital subtraction angiography have been used to evaluate in-stent neointimal formation in addition to stent apposition to the vessel wall,12–14 these modalities were not enough to confirm neointima around the aneurysm in the present case. Fukutome et al. reported that angioscopy has proven useful in confirming the neointima after carotid artery stenting.15, 16 In the present case, angioscopy revealed thick neointima within the Carotid Wallstent except around the aneurysm neck; thus, the short covered stent was selected and deployed inside the Carotid Wallstent. Angioscopic findings were useful in deciding appropriate stent selection and stent position.

Angioscopy revealed that the aneurysm neck was narrower than during the initial treatment due to the formation of neointima, and multiple holes connected to the aneurysm between the stent struts were seen. This is the first reported case of directly observing an aneurysm neck poststenting. Yako et al. reported that relatively thick neointimal coverage was found around both edges of the aneurysm neck, whereas thin-layered neointimal coverage was noted on the struts along the center of the neck by observing optical frequency domain imaging, which was used to examine aneurysms after stent-assisted coil embolization.10 They suggested that the neointimal formation of an aneurysm neck might begin from both edges of the neck and might spread gradually along the stent toward the central portion. The angioscopic findings were consistent with these considerations, suggesting that the aneurysm was becoming smaller. Moreover, the findings visually show that the use of stents with a higher mesh density and smaller pore size, such as overlapping dual-layer stents at initial treatment, decreases the size of the aneurysm neck hole and can lead to complete occlusion of the aneurysm.

Lessons

Angioscopy is useful for confirming neointimal formation within previously placed stents when re-stenting. In this report, angioscopic observation visually shows that using a stent with a higher mesh density and smaller pore size is associated with complete aneurysm occlusion.

Disclosures

The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper.

Author Contributions

Conception and design: Hayami, Aketa, Shin. Acquisition of data: Fukumori, Matsuoka. Analysis and interpretation of data: Shin. Reviewed submitted version of manuscript: Fukutome, Shiraishi. Approved the final version of the manuscript on behalf of all authors: Fukutome. Administrative/technical/material support: Aketa, Mitsui, Mori. Study supervision: Tei, Shin, Motoyama.

Supplemental Information

Videos

  Video 1. https://vimeo.com/990128570.

  Video 2. https://vimeo.com/990130840.

Correspondence

Kenji Fukutome: Osaka Police Hospital, Osaka, Japan. kenjifukutome82@gmail.com.
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