What is the significance of a beaded appearance of the extracranial Internal Carotid Artery (ICA) in relation to vision loss?

From the Guidelines

The beaded appearance of the extracranial internal carotid artery (ICA) associated with vision loss suggests fibromuscular dysplasia (FMD) causing ocular ischemic syndrome, and immediate management with antiplatelet therapy, such as aspirin 81-325mg daily, and blood pressure control is recommended. According to the 2021 guideline for the prevention of stroke in patients with stroke and transient ischemic attack 1, FMD is a nonatherosclerotic segmental disease that can result in arterial stenosis, occlusion, intraluminal thrombus, aneurysm, or dissection. The beaded appearance on imaging represents alternating areas of stenosis and dilation in the arterial wall due to fibrous tissue growth in the media of the vessel.

Key Considerations

• The 2011 ASA/ACCF/AHA/AANN/AANS/ACR/ASNR/CNS/SAIP/SCAI/SIR/SNIS/SVM/SVS guideline on the management of patients with extracranial carotid and vertebral artery disease recommends annual noninvasive imaging of the carotid arteries for patients with FMD to detect changes in the extent or severity of disease 1.
• Revascularization procedures like carotid angioplasty or stenting may be necessary in severe cases with significant stenosis, as suggested by the 2011 guideline 1.
• Patients should undergo complete ophthalmologic evaluation including visual acuity testing, fundoscopy, and fluorescein angiography to assess retinal perfusion.

Management

• Antiplatelet therapy, such as aspirin 81-325mg daily, to prevent thromboembolism 1.
• Blood pressure control, with a target of less than 140/90 mmHg.
• Statins, such as atorvastatin 20-40mg daily, may be considered to reduce the risk of cardiovascular events.
• Regular follow-up with both vascular and ophthalmology specialists is essential to monitor disease progression and adjust treatment as needed.

From the Research

Beaded Appearance of Extracranial ICA with Vision Loss

• The beaded appearance of the extracranial internal carotid artery (ICA) can be associated with various conditions, including fibromuscular dysplasia (FMD) 2 and idiopathic extracranial internal carotid artery vasospasm (IEICAV) 3.
• FMD is a multifaceted arterial disease that can cause stenosis or occlusion of the ICA, leading to vision loss and other symptoms 2.
• IEICAV is a rare condition characterized by spontaneous, recurrent, and reversible vasoconstriction of the cervical ICA, which can cause vision loss, headaches, and other symptoms 3.
• A study on ophthalmologic manifestations of internal carotid artery dissection found that 62% of patients had ophthalmologic symptoms or signs, including painful Horner syndrome and transient monocular visual loss 4.
• Anatomical variations of the ICA, such as kinking or coiling, can also be associated with vision loss and other symptoms 5.
• In cases of tandem occlusions of the extra- and intracranial carotid arteries, interventional treatment with mechanical thrombectomy and stenting can be effective in restoring blood flow and improving vision 6.

Possible Causes of Vision Loss

• Vision loss can be caused by a range of factors, including:
  • Stenosis or occlusion of the ICA due to FMD or other conditions 2
  • Vasospasm of the ICA, such as IEICAV 3
  • Anatomical variations of the ICA, such as kinking or coiling 5
  • Dissection of the ICA, which can cause painful Horner syndrome and transient monocular visual loss 4
  • Tandem occlusions of the extra- and intracranial carotid arteries, which can be treated with interventional therapy 6

Diagnostic and Treatment Approaches

• Diagnostic approaches for beaded appearance of the extracranial ICA with vision loss may include:
  • Imaging studies, such as magnetic resonance angiography (MRA) and computed tomography angiography (CTA) 5
  • Catheter-based angiography and percutaneous angioplasty for renal FMD 2
• Treatment approaches may include:
  • Interventional therapy, such as mechanical thrombectomy and stenting, for tandem occlusions of the extra- and intracranial carotid arteries 6
  • Medical therapy, such as vasodilators and antiplatelet agents, for IEICAV 3
  • Surgical therapy, such as angioplasty and stenting, for FMD and other conditions 2