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Table of Contents    
Year : 2022  |  Volume : 70  |  Issue : 4  |  Page : 1671-1673

Delayed Horner's Syndrome after Carotid Stenting

Department of Neurology, Aster Medcity, Kochi, Kerala, India

Date of Submission10-Oct-2020
Date of Decision08-Sep-2021
Date of Acceptance16-Sep-2021
Date of Web Publication30-Aug-2022

Correspondence Address:
Boby V Maramattom
Department of Neurology, Aster Medcity, Kochi, Kerala
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0028-3886.355103

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How to cite this article:
Meleth HA, Maramattom BV. Delayed Horner's Syndrome after Carotid Stenting. Neurol India 2022;70:1671-3

How to cite this URL:
Meleth HA, Maramattom BV. Delayed Horner's Syndrome after Carotid Stenting. Neurol India [serial online] 2022 [cited 2023 Dec 8];70:1671-3. Available from:


A 70-year-old man underwent right carotid stenting with a CGuardTM Embolic Prevention System (EPS). Nine hours after the procedure, he developed dysarthria and left facial weakness, and gradually progressive left hemiparesis. The magnetic resonance imaging (MRI) of the brain showed multiple small infarcts in the right internal carotid artery (ICA) territory. Repeat digital subraction angiography (DSA) on day 2 showed poor distal expansion of the stent. Another CGuardTM stent was telescoped inside the first one. No new infarctions were noted on computed tomography (CT) the next day. On day 4, he developed status epilepticus requiring anticonvulsants to achieve burst suppression (BS). His pupillary light reactions diminished with BS and the pupil sizes were noted as 3 mm. On day 7, pupillary asymmetry was noted (right; 2.5 and left 4 mm), both remained unreactive to light. An urgent CT of the brain showed no new changes. On day 8, anisocoria increased (right 2 and left 4 mm) with unreactive pupils.

A duplex ultrasound confirmed a patent stent without a carotid wall hematoma. A bedside phenylephrine test was performed with 1 and 10% phenylephrine and the pupillary changes were photographed and measured with an ocular ultrasound. An early, sustained asymmetric and reversible pupillary mydriasis was demonstrated in the right eye, consistent with denervation hypersensitivity and third-order sympathetic neuron involvement [Table 1]. By day 10, the IV anticonvulsants were tapered. By day 15, the pupillary sizes had normalized [Figure 1].
Table 1: Depicts the pupillary size measurements by ocular ultrasound in mm after instillation of phenylephrine 1 and 10%

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Figure 1: Shows the different pupil sizes at the baseline (a and c) right eye, (b and d) left eye and post phenylephrine instillation (e and f). (g) shows the pre-stenting watershed infarct in the right MCA-ACA territory. (h) shows the pre-CTA showing the right ICA origin stenosis. (i) shows the post-stenting artery to artery embolic strokes. (j) shows the overlapping stents placed in the right ICA

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Our patient demonstrated prompt mydriasis in the right eye, compatible with a post-ganglionic Horner's syndrome with a single drop of 10% phenylephrine. This was serially monitored clinically and ultrasonologically at 0, 10, 30, min and 6 h[1] [Table 1]. Due to the drug-induced coma, pharmacological testing was required to confirm post-ganglionic horner's syndrome (HS) [Table 2]. Of the medications used for the diagnosis of HS, only phenylephrine drops are easily available [Table 3] [Figure 2].
Table 2: Causes of a post-ganglionic [third order] Horner's syndrome1

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Table 3: The interpretation of the various bedside pharmacological tests

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Figure 2: Shows a diagrammatic representation of the utility of different pharmacological agents at different levels of the oculo-sympathetic system

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Carotid artery stenting (CAS) can produce HS by stretching the arterial wall or with a wall hematoma and is seen within a few hours after CAS. Our patient developed delayed HS 7 days after CAS, due to a gradual stent expansion and stretching of the intracranially destined sympathetic fibers (ICN) in the wall of the ICA.[2] Self-expanding nitinol carotid stents exert a high degree of outward force till they reach their predetermined caliber. Our patient had two overlapping self-expanding stents exerting significant outward pressure on the carotid wall and ICN injury. The CGuardTM stent exerts a high outward pressure compared to closed cell stents such as Xact, but less than the open-cell stents such as Protégé.[3],[4]

This report is unusual in reporting a delayed post-carotid stenting HS as well as the role of bedside ocular pharmacological testing and ocular ultrasound in BS coma.

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Conflicts of interest

There are no conflicts of interest.

 » References Top

Schmidt FA, Ruprecht K, Connolly F, Maas MB, Paul F, Hoffmann J, et al. B-mode ultrasound assessment of pupillary function: Feasibility, reliability and normal values. PLoS One 2017;12:e0189016.  Back to cited text no. 1
Ringer AJ, Fessler RD, Qureshi AI, Guterman LR, Hopkins LN. Horner's syndrome after carotid artery stenting: Case report. Surg Neurol 2000;54:439-43.  Back to cited text no. 2
Wissgott C, Schmidt W, Brandt-Wunderlich C, Behrens P, Andresen R. Clinical results and mechanical properties of the carotid CGUARD double-layered embolic prevention stent. J Endovasc Ther 2017;24:130-7.  Back to cited text no. 3
de Vries EE, Kök M, Hoving AM, Slump CH, Toorop RJ, de Borst GJ. (In) comparability of carotid artery stent characteristics: A systematic review on assessment and comparison with manufacturer data. Cardiovasc Intervent Radiol 2020;43:1430-7.  Back to cited text no. 4


  [Figure 1], [Figure 2]

  [Table 1], [Table 2], [Table 3]


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