Use of a flow diverter in a small-caliber end artery anterior choroidal dissecting pseudoaneurysm: illustrative case

Griffin Ernst Departments of Neurosurgery and

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Noor A. Mahmoud Neurology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma

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Audrey Grossen Departments of Neurosurgery and

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Andrew Bauer Departments of Neurosurgery and

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BACKGROUND

Anterior choroidal artery (AChA) fusiform aneurysms are exceedingly rare and associated with high rebleeding and mortality rates. Their difficult anatomy comes with a broad range of treatment options, including bypass, stent-assisted coiling, and flow diversion. Currently, flow diverters are approved for large-caliber internal carotid artery segment aneurysms. However, many institutions have expanded their use to distal small-caliber vessels, which raises questions regarding device sizing and long-term patency. The authors present a dissecting distal AChA fusiform pseudoaneurysm treated successfully with flow diversion.

OBSERVATIONS

A 40-year-old woman with monoclonal gammopathy of unknown significance, lichen sclerosis, and an unspecified connective tissue disease presented with diffuse subarachnoid hemorrhage. She had a dissecting, 5 × 3–mm, left AChA pseudoaneurysm 4 mm distal to the origin of the vessel. A 2.5-mm flow redirection endoluminal device was deployed. There were no procedural complications. A 6-month cerebral angiogram showed device patency and no pseudoaneurysm remnant. These results were maintained at 1 year as seen on head magnetic resonance angiography.

LESSONS

Flow diversion is a successful and safe therapeutic intervention for challenging intracranial aneurysms originating from small-caliber vessels supplying eloquent vascular territories.

ABBREVIATIONS

AChA = anterior choroidal artery; ACoA = anterior communicating artery; FDD = flow diverter device; FRED = flow redirection endoluminal device; ICA = internal carotid artery; MRI = magnetic resonance imaging

BACKGROUND

Anterior choroidal artery (AChA) fusiform aneurysms are exceedingly rare and associated with high rebleeding and mortality rates. Their difficult anatomy comes with a broad range of treatment options, including bypass, stent-assisted coiling, and flow diversion. Currently, flow diverters are approved for large-caliber internal carotid artery segment aneurysms. However, many institutions have expanded their use to distal small-caliber vessels, which raises questions regarding device sizing and long-term patency. The authors present a dissecting distal AChA fusiform pseudoaneurysm treated successfully with flow diversion.

OBSERVATIONS

A 40-year-old woman with monoclonal gammopathy of unknown significance, lichen sclerosis, and an unspecified connective tissue disease presented with diffuse subarachnoid hemorrhage. She had a dissecting, 5 × 3–mm, left AChA pseudoaneurysm 4 mm distal to the origin of the vessel. A 2.5-mm flow redirection endoluminal device was deployed. There were no procedural complications. A 6-month cerebral angiogram showed device patency and no pseudoaneurysm remnant. These results were maintained at 1 year as seen on head magnetic resonance angiography.

LESSONS

Flow diversion is a successful and safe therapeutic intervention for challenging intracranial aneurysms originating from small-caliber vessels supplying eloquent vascular territories.

ABBREVIATIONS

AChA = anterior choroidal artery; ACoA = anterior communicating artery; FDD = flow diverter device; FRED = flow redirection endoluminal device; ICA = internal carotid artery; MRI = magnetic resonance imaging

Anterior choroidal artery (AChA) aneurysms account for 3%–5% of intracranial aneurysms, with the majority arising proximally at the junction with the supraclinoid internal carotid artery (ICA).1,2 Distal AChA aneurysms, those that arise from the cisternal segment of the AChA, are exceedingly rare, with only a few cases reported.2

The AChA originates from the C7 segment of the ICA and supplies eloquent structures, including the posterior limb of the internal capsule, optic tract, basal ganglia, uncus, fimbria of the fornix, hippocampal head, amygdala, piriform cortex, tela choroidea, crus cerebri of the midbrain, red nucleus, hypothalamus, and lateral geniculate body of the thalamus. Injury of ischemia from this vessel can lead to contralateral hemiplegia, hemianesthesia, homonymous hemianopsia, and dysarthria. There is very little, if any, collateral blood supply for the AChA, which adds risk to any treatment that could occlude the vessel.

In contrast to the more common AChA saccular aneurysms, which occur at the origin of the vessel secondary to turbulence and vessel branching, distal AChA aneurysms are often fusiform, because they do not have similar large-vessel branching. They are associated with a higher risk of rebleeding and death because of their formidable anatomy, often requiring advanced treatment techniques, including bypass, stent-assisted coiling, and, most recently, flow diversion.2 Although initially used for wide-neck ICA aneurysms, the off-label use of flow diversion has been expanding, especially as newer and smaller flow diverter devices (FDDs) have become available.3 In carefully selected patients, the use of flow diverters to treat ruptured intracranial aneurysms may result in high rates of angiographic occlusion and good clinical outcomes.4 Here we present a novel pathology of a ruptured dissecting AChA fusiform pseudoaneurysm treated successfully with flow diversion with excellent surgical and clinical outcomes.

Illustrative Case

History and Examination

A 40-year-old woman with monoclonal gammopathy of unknown significance, lichen sclerosis, and an unspecified connective tissue disease presented with diffuse subarachnoid hemorrhage (World Federation of Neurosurgical Societies grade 1, Hunt and Hess grade 2, modified Fisher grade 3). A cerebral digital subtraction angiogram revealed a dissecting, 5 × 3–mm, left AChA pseudoaneurysm 4 mm distal to the origin of the vessel (Fig. 1).

FIG. 1.
FIG. 1.

Lateral angiogram with left ICA injection (left) showing a fusiform dissecting aneurysm (arrows) of the AChA distal to the origin of the vessel. Angiogram prior to posterior communicating artery filling (right).

A flow redirection endoluminal device (FRED) (2.5 mm, 8/13 working/total length, FRED Jr., Microvention) was deployed within the vessel proximal to the aneurysm, following an infusion of 5 mg of verapamil to facilitate proper sizing (Fig. 2). After the procedure, the patient remained neurologically intact. Initially, she was loaded with 650 mg aspirin and 150 mg Plavix (Bristol Myers Squibb/Sanofi); however, after a Plavix platelet function test was performed, she was found to be a Plavix nonresponder and was ultimately discharged on dual antiplatelet therapy of 81 mg aspirin and 90 mg ticagrelor twice daily. Repeat cerebral angiography at 6 months showed a patent FDD (Fig. 3) and no pseudoaneurysm remnant with a nonfocal physical examination. This trend continued at the 1-year magnetic resonance imaging (MRI)/magnetic resonance angiography follow-up, with no recurrent aneurysm and a patent AChA vessel (Fig. 4).

FIG. 2.
FIG. 2.

Lateral angiogram after FRED deployment. Arrows indicate the proximal and distal stent. Arrowhead indicates flow stasis in the aneurysm. The area of stenosis resolved on subsequent angiograms.

FIG. 3.
FIG. 3.

Six-month follow-up lateral angiogram showing absent aneurysm and patent AChA (arrow).

FIG. 4.
FIG. 4.

One-year follow-up axial time-of-flight MRI. Arrows indicate a patent left AChA with no residual aneurysm. Images represent 2 different slices.

Description of Endovascular Technique

The right femoral artery was canalized with a 6-French sheath. A 5-French diagnostic catheter with 0.035-inch angled Glidewire (Terumo) was used to select the left ICA. A left ICA injection revealed the AChA fusiform aneurysm measuring 5 × 3 mm and originating 4 mm distal to the origin of the AChA. The vessel distal to the aneurysm was patent and measured 1.2 mm in diameter. A Benchmark guide catheter was advanced into the petrous carotid, and a 0.021-inch Headway microcatheter (Microvention) was advanced proximal to the aneurysm over a 0.014-inch Synchro-2 microcatheter. We slowly infused 5 mg of verapamil into the AChA to treat local vasospasm and ensure proper sizing of the device. A 2.5-mm × 8/13 (working length/total length) FRED Jr. flow diverter was selected and deployed within the vessel. Postdeployment injections showed good opening with apposition against the vessel wall with contrast stasis within the aneurysm. The patient remained neurologically intact following the procedure and was treated with dual antiplatelet therapy.

Post-procedure

The patient was monitored in the neurosciences intensive care unit for delayed cerebral ischemia. On postoperative bleed day 6, the finding of transcranial Doppler ultrasound was concerning for vasospasm, and she was taken for a repeat diagnostic angiogram. The bilateral anterior cerebral, middle cerebral, and basilar arteries were in moderate vasospasm and subsequently treated with an infusion of 20 mg of verapamil each. Her recovery was otherwise uneventful, and she was discharged after having spent a total of 19 days as an inpatient.

At an initial 6-week follow-up, she continued to do well with only mild subjective memory deficits. Six months later, repeat cerebral angiography showed complete occlusion of the dysplastic AChA aneurysm and a patent parent vessel with FDD (Fig. 3). At the 1-year follow-up, the AChA remained widely patent, and there was no residual pseudoaneurysm as seen by time-of-flight MRI (Fig. 4).

Patient Informed Consent

The necessary patient informed consent was obtained in this study.

Discussion

Observations

AChA aneurysms are a rare entity, accounting for only 3%–5% of intracranial aneurysms.1 When present, they are usually saccular aneurysms formed at the origin of the artery. Several studies have demonstrated the safety and efficacy of treating these types of aneurysms with flow diversion5–13; however, these cases describe the proximal and distal ends of the flow diverter seated in the ICA. This was in contrast to our case, which saw a fusiform distal aneurysm with the proximal and distal ends of the flow diverter deployed within the AChA proper. Placement of the flow diverter in this fashion was required because the aneurysm arose from a side wall of the AChA distal to its branch point from the ICA. A flow diverter placed within the ICA would have had no effect on the aneurysm, because blood would still be pulled into a widely patent AChA. This raises important concerns because the AChA is a small-caliber vessel with an eloquent end artery territory. The success of an FDD is predicated on the epithelialization of the stent, which seals off the aneurysm being treated. There are concerns that this growth can result in stenosis, especially in already small vessels, thereby limiting flow and contributing to morbidity and mortality.

The small size of the vessel is the main challenge to treatment in most fusiform choroidal artery aneurysms. The vessel does not lend itself well to surgical clipping or bypass because of the small size and fragile nature of the wall of a dissecting pseudoaneurysm. Flow diversion in small vessels can be difficult because of a failure of the device to properly open and oppose the wall, leading to vessel occlusion. It is well known that occlusion of the AChA proximal to the plexal point (point of entry to the choroid plexus) results in hemiplegia, hemianesthesia, and contralateral hemianopia. It is important that any treatment of the AChA does not lead to the occlusion of AChA perforators.

The FRED Jr. is a smaller flow diverter with a diameter of 2.5–3 mm that can be used in small-diameter vessels. The small size of the AChA necessitated a smaller microcatheter for deployment of the flow diverter. At the time of this case, the FRED Jr. was the only flow diverter that could fit in the 0.021-inch Headway microcatheter. A prospective study performed by Sivasankar et al.14 looked at their results of FRED Jr. placement in 12 patients with 15 total aneurysms located in small vessels: distal anterior cerebral artery, anterior communicating artery (ACoA), ACoA/A1-A2-ACoA junction, middle cerebral artery, V4 segment, and posterior cerebral artery. The average size of the vessels was 2.5 mm proximally and 2.1 mm distally. They had successful deployment in 100% of cases without a single occurrence of transient ischemic attack, stroke, or death, despite 3 cases with in-stent stenosis.14

In another retrospective review of the safety and efficacy of the FRED Jr. in small vessels, Sweid et al.15 looked at 598 treated aneurysms, 12.20% of which were associated with small-caliber vessels (distal to the circle of Willis). They showed a nonsignificant difference of aneurysms treated in small-caliber vessels as compared with larger-caliber vessels with a stroke rate of 2.99%, delayed aneurysmal rupture and distal intraparenchymal hemorrhage rate of 3.7%, and morbidity of 5.8%. The difference in complete aneurysm occlusion was also nonsignificant at 75.3%.15 This shows that flow diversion with an appropriately sized device is as safe and efficacious in smaller vessels as in larger ones.

Last, in a retrospective review, Bender et al.16 sought to characterize the effect that a flow diverter has on small vessels, specifically regarding vessel stenosis, and how this might result in complications. Sixty-seven 2.5-mm Pipeline embolization devices were used to treat aneurysms in vessels measuring <2.0 mm in 57 patients. Seventy-one percent of the patients presented for follow-up diagnostic angiography. Four cases (7.3%) showed >25%–50% in-stent vessel diameter reduction, and 2 cases (3.6%) showed >50% reduction at the proximal stent landing zone. Distally, 1 (1.8%) showed >25%–50% in-stent vessel diameter reduction. There were no cases of in-stent vessel reduction >50%. Of the patients available for follow-up, complete aneurysm occlusion occurred in 88% at 6 months and in 86% at 12 months.16

We acknowledge the following limitations of our case report. We describe the off-label use of an FDD in a small-caliber vessel, with the hope of future prospective studies to assess the outcomes in a larger cohort and a longitudinal follow-up. AChA occlusion following a flow diverter stent is rare. However, if the branch arises from the aneurysm sac, proximity of the posterior communicating artery origin to the AChA, or shorter segment of AChA (not in our patient), occlusion can lead to serious complications. Decisions should be made on an individual basis until higher-quality data supporting an FDD in small-caliber vessels are available.

Lessons

Flow diversion is a safe and successful therapeutic intervention for challenging intracranial aneurysms within eloquent vascular territories such as the distal AChA, despite its small caliber. The off-label use of an FDD continues to expand. This is the only case report in the literature describing successful flow diversion treatment in the AChA.

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: Ernst, Bauer. Acquisition of data: Ernst, Grossen, Bauer. Analysis and interpretation of data: Ernst, Grossen, Bauer. Drafting the article: Ernst, Mahmoud, Grossen. Critically revising the article: Ernst, Mahmoud, Bauer. Reviewed submitted version of manuscript: all authors. Approved the final version of the manuscript on behalf of all authors: Ernst. Administrative/technical/material support: Grossen. Study supervision: Bauer.

Supplemental Information

Previous Presentations

This case was previously presented as an abstract at the Society of Vascular and Interventional Neurology Annual Meeting, Los Angeles, CA, November 16–18, 2022.

References

  • 1

    Piotin M, Mounayer C, Spelle L, Williams MT, Moret J. Endovascular treatment of anterior choroidal artery aneurysms. AJNR Am J Neuroradiol. 2004;25(2):314318.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 2

    Dolati P, Sutherland G, Wong J, Hudon M, Goyal M. Distal anterior choroidal artery aneurysm following iatrogenic posterior cerebral artery occlusion : a case report and review of literature. Acta Neurochir (Wien). 2012;154(1):5357.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 3

    Limbucci N, Leone G, Renieri L, et al. Expanding indications for flow diverters: distal aneurysms, bifurcation aneurysms, small aneurysms, previously coiled aneurysms and clipped aneurysms, and carotid cavernous fistulas. Neurosurgery. 2020;86(suppl 1):S85S94.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 4

    Madaelil TP, Moran CJ, Cross DT 3rd, Kansagra AP. flow diversion in ruptured intracranial aneurysms: a meta-analysis. AJNR Am J Neuroradiol. 2017;38(3):590595.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 5

    Yu J, Xu N, Zhao Y, Yu J. Clinical importance of the anterior choroidal artery: a review of the literature. Int J Med Sci. 2018;15(4):368375.

  • 6

    Bhogal P, Ganslandt O, Bäzner H, Henkes H, Aguilar Perez M. Treatment of unruptured, saccular, anterior choroidal artery aneurysms with flow diversion : a single centre experience. Clin Neuroradiol. 2019;29(3):459465.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 7

    Brinjikji W, Kallmes DF, Cloft HJ, Lanzino G. Patency of the anterior choroidal artery after flow-diversion treatment of internal carotid artery aneurysms. AJNR Am J Neuroradiol. 2015;36(3):537541.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 8

    Srinivasan VM, Ghali MGZ, Cherian J, et al. Flow diversion for anterior choroidal artery (AChA) aneurysms: a multi-institutional experience. J Neurointerv Surg. 2018;10(7):634637.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 9

    Kühn AL, Hou SY, Perras M, et al. Flow diverter stents for unruptured saccular anterior circulation perforating artery aneurysms: safety, efficacy, and short-term follow-up. J Neurointerv Surg. 2015;7(9):634640.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 10

    Topcuoglu OM, Arat A, Peker A, Sarikaya B. Intermediate catheter placement distal to the cerebral aneurysm during flow diversion embolization with the Surpass device. J Neurointerv Surg. 2018;10(12):e35.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 11

    Ghali MGZ, Srinivasan VM, Wagner KM, Lam S, Johnson JN, Kan P. Anterior choroidal artery aneurysms: influence of regional microsurgical anatomy on safety of endovascular treatment. J Cerebrovasc Endovasc Neurosurg. 2018;20(1):4752.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 12

    Rangel-Castilla L, Munich SA, Jaleel N, et al. Patency of anterior circulation branch vessels after Pipeline embolization: longer-term results from 82 aneurysm cases. J Neurosurg. 2017;126(4):10641069.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 13

    Zanaty M, Chalouhi N, Jabbour P, Starke RM, Hasan D. The unusual angiographic course of intracranial pseudoaneurysms. Asian J Neurosurg. 2015;10(4):327330.

  • 14

    Sivasankar R, Shrivastava M, Limaye US. Experience with FRED junior flow diverter in treatment of cerebral aneurysms at or distal to the circle of Willis. J Clin Neurosci. 2019;69:166169.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 15

    Sweid A, Starke RM, Herial N, et al. Flow diversion for small caliber vessel aneurysms: efficacy, safety, and functional outcome. J Neurosurg Sci. 2019;63(6):702713.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 16

    Bender MT, Zarrin DA, Campos JK, et al. Tiny pipes: 67 cases of flow diversion for aneurysms in distal vessels measuring less than 2.0 mm. World Neurosurg. 2019;127:e193e201.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • Collapse
  • Expand
  • FIG. 1.

    Lateral angiogram with left ICA injection (left) showing a fusiform dissecting aneurysm (arrows) of the AChA distal to the origin of the vessel. Angiogram prior to posterior communicating artery filling (right).

  • FIG. 2.

    Lateral angiogram after FRED deployment. Arrows indicate the proximal and distal stent. Arrowhead indicates flow stasis in the aneurysm. The area of stenosis resolved on subsequent angiograms.

  • FIG. 3.

    Six-month follow-up lateral angiogram showing absent aneurysm and patent AChA (arrow).

  • FIG. 4.

    One-year follow-up axial time-of-flight MRI. Arrows indicate a patent left AChA with no residual aneurysm. Images represent 2 different slices.

  • 1

    Piotin M, Mounayer C, Spelle L, Williams MT, Moret J. Endovascular treatment of anterior choroidal artery aneurysms. AJNR Am J Neuroradiol. 2004;25(2):314318.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 2

    Dolati P, Sutherland G, Wong J, Hudon M, Goyal M. Distal anterior choroidal artery aneurysm following iatrogenic posterior cerebral artery occlusion : a case report and review of literature. Acta Neurochir (Wien). 2012;154(1):5357.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 3

    Limbucci N, Leone G, Renieri L, et al. Expanding indications for flow diverters: distal aneurysms, bifurcation aneurysms, small aneurysms, previously coiled aneurysms and clipped aneurysms, and carotid cavernous fistulas. Neurosurgery. 2020;86(suppl 1):S85S94.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 4

    Madaelil TP, Moran CJ, Cross DT 3rd, Kansagra AP. flow diversion in ruptured intracranial aneurysms: a meta-analysis. AJNR Am J Neuroradiol. 2017;38(3):590595.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 5

    Yu J, Xu N, Zhao Y, Yu J. Clinical importance of the anterior choroidal artery: a review of the literature. Int J Med Sci. 2018;15(4):368375.

  • 6

    Bhogal P, Ganslandt O, Bäzner H, Henkes H, Aguilar Perez M. Treatment of unruptured, saccular, anterior choroidal artery aneurysms with flow diversion : a single centre experience. Clin Neuroradiol. 2019;29(3):459465.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 7

    Brinjikji W, Kallmes DF, Cloft HJ, Lanzino G. Patency of the anterior choroidal artery after flow-diversion treatment of internal carotid artery aneurysms. AJNR Am J Neuroradiol. 2015;36(3):537541.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 8

    Srinivasan VM, Ghali MGZ, Cherian J, et al. Flow diversion for anterior choroidal artery (AChA) aneurysms: a multi-institutional experience. J Neurointerv Surg. 2018;10(7):634637.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 9

    Kühn AL, Hou SY, Perras M, et al. Flow diverter stents for unruptured saccular anterior circulation perforating artery aneurysms: safety, efficacy, and short-term follow-up. J Neurointerv Surg. 2015;7(9):634640.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 10

    Topcuoglu OM, Arat A, Peker A, Sarikaya B. Intermediate catheter placement distal to the cerebral aneurysm during flow diversion embolization with the Surpass device. J Neurointerv Surg. 2018;10(12):e35.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 11

    Ghali MGZ, Srinivasan VM, Wagner KM, Lam S, Johnson JN, Kan P. Anterior choroidal artery aneurysms: influence of regional microsurgical anatomy on safety of endovascular treatment. J Cerebrovasc Endovasc Neurosurg. 2018;20(1):4752.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 12

    Rangel-Castilla L, Munich SA, Jaleel N, et al. Patency of anterior circulation branch vessels after Pipeline embolization: longer-term results from 82 aneurysm cases. J Neurosurg. 2017;126(4):10641069.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 13

    Zanaty M, Chalouhi N, Jabbour P, Starke RM, Hasan D. The unusual angiographic course of intracranial pseudoaneurysms. Asian J Neurosurg. 2015;10(4):327330.

  • 14

    Sivasankar R, Shrivastava M, Limaye US. Experience with FRED junior flow diverter in treatment of cerebral aneurysms at or distal to the circle of Willis. J Clin Neurosci. 2019;69:166169.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 15

    Sweid A, Starke RM, Herial N, et al. Flow diversion for small caliber vessel aneurysms: efficacy, safety, and functional outcome. J Neurosurg Sci. 2019;63(6):702713.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 16

    Bender MT, Zarrin DA, Campos JK, et al. Tiny pipes: 67 cases of flow diversion for aneurysms in distal vessels measuring less than 2.0 mm. World Neurosurg. 2019;127:e193e201.

    • PubMed
    • Search Google Scholar
    • Export Citation

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