Carotid Occlusive Disease

Carotid occlusive disease is another systemic condition that has some very significant ophthalmic manifestations.  For the sake of brevity, this article will primarily highlight the systemic information we need to know for the OKAP, including transient ischemic attacks (TIAs).  I will post other articles pertaining to some of the ophthalmic manifestations of carotid occlusive disease, such as ocular ischemic syndrome and transient monocular visual loss (specifically amaurosis fugax).  Hopefully this will be a shorter one!

Key Facts

Carotid Stenosis

  • Carotid stenosis is typically evaluated by a carotid duplex ultrasound.
  • Asymptomatic carotid stenosis carries a 2% annual risk of stroke.
  • Patients who have asymptomatic carotid stenosis should be evaluated by their primary care physician for risk factors of atherosclerotic disease (hypertension, hypercholesterolemia, smoking, etc.).
  • Elevated plasma homocysteine levels have been linked to extracranial carotid stenosis, increased stroke risk, and occlusive vascular disease.
  • Asymptomatic carotid stenosis > 80% should be considered for an carotid endarterectomy (CEA), as concluded by the Asymptomatic Carotid Atherosclerosis Study.
  • Typical medical treatment includes antiplatelet therapy consisting of aspirin 325 mg/day or Aggrenox (aspirin + dipyridamole).  Plavix (clopidogrel) is an alternative treatment if aspirin is contraindicated.

Transient Ischemic Attack and Stroke

Manifestation of Carotid Stenosis

Transient Monocular Visual Loss (TMVL)

Retinal infarct

Transient Ischemic Attack (TIA)

Annual Stroke Rate

2%

3%

8%

  • Untreated patients with TMVL, retinal infarcts, or TIAs have a 30% risk of MI and 18% risk of death over a 5-year period!
  • Transesophageal cardiac ultrasonography + ambulatory Holter monitoring is recommended in all patients with TMVL, retinal infarcts, or TIAs, to rule out a cardiac source for embolic disease.
  • The North American Symptomatic Carotid Endarterectomy Trial (NASCET) determined that a carotid endarterectomy should be performed in patients with 70-99% carotid stenosis.
  • Antiplatelet therapy (aspirin 325 mg/day, Aggrenox, or clopidogrel) should be initiated for medical management.

Sample Questions (answers at the bottom of the page)

  1. Which of the following is TRUE about the risk of stroke in carotid stenosis?

    A.  The annual risk of stroke is higher in patients with transient monocular visual loss than in patients with transient ischemic attacks.
    B.  The annual risk of stroke is higher in patients with transient monocular visual loss than in patients with a branch retinal artery occlusion.
    C.  The annual risk of stroke is lower in patients with asymptomatic carotid stenosis than in patients with an audible bruit.
    D.  The annual risk of stroke is lower in patients with a branch retinal artery occlusion than in patients with a transient ischemic attack.
     
  2. A 53-year-old male with hypertension complains of episodic "dimming" for 2-3 minutes in the right eye several times over the past month.  Which of the following statements is FALSE?

    A.  He has a 2% annual risk of stroke.
    B.  He should be evaluated with a carotid and cardiac ultrasound.
    C.  He has an increased risk of a myocardial infarction over the next 5 years.
    D.  He should start taking aspirin 81 mg per day.

Sample Question Answers

  1. D.  Retinal ischemia (such as a branch retinal artery occlusion) has a 3% annual risk of stroke.  Transient monocular visual loss has a 2% annual risk of stroke, which is the same as asymptomatic carotid stenosis.  An audible bruit has a 1.5% annual risk of stroke.  Transient ischemic attacks have an 8% annual risk of stroke.
  2. D.  All patients with suspicion (or diagnosis) of carotid disease should be started on aspirin 325 mg/day, Aggrenox, or clopidogrel.  Transient monocular visual loss has a 2% annual risk of stroke.  Both carotid and cardiac ultrasounds should be obtained in the workup of transient monocular visual loss.  If left untreated, patients with carotid disease have a 30% risk of myocardial infarction within 5 years.

References and Additional Reading

  1. Basic and Clinical Science Course, Section 1:  Update on General Medicine.  American Academy of Ophthalmology, 2017-2018 edition.

Do you have any suggestions on what else might be important to know about carotid occlusive disease?  Do you have any tips for helping to remember all of this information?  Do you have any requests for specific topics to cover?  Leave a comment or e-mail us at:  ophthreview [at] gmail [dot] com!