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Amaurosis Fugax
Essentials for the Ophthalmic Practitioner
Amaurosis fugax
 Amaurosis – darkening, obscure
 Fugax – fugitive
AF and stroke: Statistical evidence
 Strokes per year in US: 700,000
 ≈ 30% are recurrent stroke
 25% mortality
 TIA and AF: greatest risk of stroke is 1st week*
 TIA and AF: 10.5% risk of stroke in 90 days*
* Rothwell,PM, et.al. Timing of TIAs preceding stroke: time window for
prevention is very short. Neurology. 2005;64:817-820
AF vision loss
 Transient (1-10 min)
 Partial to total loss
 Often begins in upper field
 Painless
 Unilateral (except if vertebrobasilar insuff.)
 Commonly no precipitating factor
 Fully reversible (w/in minutes, hrs)
AF – Outline for course discussion
I. Thromboembolism
II. Non-embolic, hemodynamic causes of AF
III. Masqueraders of true AF
IV. In-office examination
V. Primary auxiliary testing
VI. Optometric Management
VII. Medical, surgical treatment considerations
I.
Thromboembolism - ICA
Factors associated with higher risk of stroke
 ICA stenosis of 80-94%
 Age >75
 Male gender
 History of hemispheric TIA or stroke
 History of intermittent claudication
 Absence of collateral circulation
- Benavente,O.,et.al. Prognosis after transient monocular blindness associated with
carotid artery stenosis N Engl J Med. 2001 Oct 11;345(15):1084-90
Thromboembolism carotid sinus
 Biopathology of hemodynamic shear stress
 Greatest plaquing: carotid sinus outer wall
 Flow stasis = low shear stress = intimal proliferation
 Shear stress = atheroprotective endothelial response
Thromboembolism vertebral – basilar arteries
 Brain stem ischemia
 Homonymous vision symptoms
 Dipl, cortical blindness
 Vertigo, disequilibrium
 Dysphasia, dysarthria
 Medical management
 Endovascular surgery
Thromboembolism cardiac
 20% ischemic strokes
 Often calcific
 Atrial fibrillation
 Valve disease
 Prosthetic valves
 Cardiomyopathy
Thromboembolic disease Patent foramen ovale
Nearly half (43%) of young patients (<50yrs) with cryptogenic ischemic stroke in this
study have a patent foramen ovale.
MesaD, et.al. Prevalence of patent foramen ovale in young patients with cerebral
ischemic accident of unknown origin Rev Esp Cardiol. 2003 Jul;56(7):662-8
Other conditions with clot risk
 Pregnancy; birth control pills
 Sickle cell
 Hypercoagulable conditions
 Mostly pediatric, young adult
 Inherited thrombophilias
 Protein C, Protein S deficiencies
 Factor V Leiden (blood clotting protein)
 Antithrombin III deficiency
II.
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Hemodynamic cause
Relative retinal, ON
vascular insufficiency
Generalized atherosclerosis →
Rapid drop in CRA pressure
Induced by
Exercise
Bright lt./brightness intolerance
Postural changes / hypotensive episodes
Low cardiac output
ECA, ICA, ophthalmic artery high grade stenosis
Takayasu’s disease
 Hyperviscosity conditions
 Gaze-induced AF secondary to orbital tumor
 ICA dissection
50% pts w/ dissection and stroke have no history of antecedent neck trauma
- BassiP, et.al. Cervical cerebral artery dissection: A multicenter prospective study.
Neurol Sci. 2003;24 (suppl 1): S4-S7
 Carotid aneurysm
Idiopathic cause
 No identifiable lesion or hemodynamic cause
 Vasospastic? Migraine?
III. Ocular presentations w/ transient blur
 Transient obscurations
 Papilledema,  intracranial pressure
 “graying out” of vision / seconds / rarely total loss
 Occult ION
 Malignant hypertension
 Prodrome of CRVO
 Optic neuritis
 Compression of ON, optic chiasm
Other “sudden loss of vision” considerations
 Glaucoma / extreme  IOP
 Vitreous hemorrhage
 Vitreous floaters
 Hyphema
 “Overnight” cataract or PCO
 Corneal decompensation, edema
 Numerous others
IV.
In-office examination
Detailed CC, history
BP; pulse; cervical and heart auscultation
Neurologic eye testing
SLE
Ophthalmoloscopy
o Retinal edema; hemorrhage
o Disc edema; pallor
o Arteriole attenuation; emboli
 Ocular ischemic syndrome
 Hypoperfusion syndrome; rubeosis
 ODM – measure CRA pressure
o Digital ODM w/ contralateral comparison
 Exophthalmometry – r/o orbital disease
Prospective study
 145 pts. over 3 years referred for Doppler studies due to eye signs, symptoms
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Predictive value of identifying significant ICA stenosis
- 20.0% positive with amaurosis fugax
- 18.2% positive with Hollenhorst plaque(s)
- 20.0% positive with hypoperfusion retinopathy
- other eye findings demonstrated poor predictive value
- McCullough, HK, et.al.; Ocular findings as predictors of carotid artery occlusive
disease: is carotid imaging justified? J Vasc Surg. 2004 Aug;40(2):279-86
V. Primary auxiliary tests
Laboratory
 Sed rate and CRP (abnl >30mm/hr; >0.9mg/dL)
 CBC w/ differential
 Platelets (ref. range 150,000-350,000/mm3)
 Lipid panel (lipoproteins, cholesterol, triglycerides)
 Glycosylated Hb and FBS
 Homocysteine if elevated: 2X RR of stroke
 Antinuclear antibody (Lupus)
 Anti-phospholipid antibody
Study
Antiphospholipid Ab testing in 368 patients over 3.5 years with ophthalmic occlusive
disease
-86 patients tested positive (23.4%) vs. 5% general pop.
-CRVO = 18% APA positive; BRVO = 24%
-CRAO = 22% APA positive; BRAO = 32%
-AION = 23%
- Palmowski-Wolfe, AM, et.al.;Antiphospholipid antibodies in ocular arterial and venous
occlusive disease Ophthalmologica. 2007;221(1):41-6
Cerebrovascular studies
 Noninvasive Doppler ultrasound
 B-mode ultrasound
 Direct view
 Color Doppler
 Trickle flow, “string sign”
 Duplex
 Subclavian steal: vertebral, subclavian
Retrospective study in the UK covering 3 years of consecutive eye clinic patients referred
for carotid Doppler
 55% were positive for ICA stenosis
 20% had >70% stenosis
- Mukherji,W.et.al. Indications and outcome of carotid Doppler ultrasound: an
ophthalmic perspective. Eur J Ophthalomol. 2004 May-Jun;14(3):240-4
Transcranial Doppler
 Pulsed
 Intracranial blood directionality, velocity
 Ophthalmic artery: antegrade? Retrograde? Steal phenomenon?
Magnetic resonance angiography
 Noninvasive
 Time-of-flight technology, excellent for blood flow evaluation
Arteriography
 “Gold standard”
 Risks
Cardiac studies
Echocardiography identified a potential cardiac or proximal aortic source for embolism in
16 / 73 (21.9%) of patients; including 8 who also had atrial fibrillation and ICA stenosis
>50%.
8/73 (11.0%) had lesions only detected by ECG.
-Mouradian,M, et.al.;Echocardiographic findings of patients with retinal ischemia or
embolism J Neuroimaging 2002 Jul;12(3):219-23
VI.
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Optometric management
Identify and manage if ocular cause
Glaucoma, BRVO, hyphema, vitreous hemorrhage, etc.
Measure BP, pulse, auscultation
Stat ESR and CRP (r/o occult GCA)
Individualize suspicion and focus of examination
Age
Health and family history
Communicate with family practitioner!
o Phone call same day; written report
 Laboratory; hematology tests
 Temporal artery biopsy if  CRP,  ESR, and GCA suspected
 Duplex/Doppler ultrasound; cerebrovascular studies
 Echocardiogram; cardiac studies
 ASA /anti-platelet option
Management concerns
 Misdiagnosis of symptoms and working dx
 Underestimate urgency of situation
 No follow-up w/ primary care physician or patient
 Diagnosis delay: referral to an inappropriate subspecialist
How would YOU manage the AF patient?
- Questionnaire sent to 1,600 GPs; 54% response
 72% would refer pt. to specialist
 36% would start anti-thrombotic treatment
- Donders,RC, et.al.;How do general practitioners diagnose and manage
patients with transient monocular loss of vision of sudden onset? J Neurol. 1999
Dec;246(12):1145-50
VII. Surgical treatment: high grade stenosis
= of proximal ICA
North American Symptomatic Carotid Endarterectomy Trial (NASCET)
Carotidendarterectomy (CEA) advised if >70% stenosis and symptomatic:
- Stroke risk: 9% in 2 years if surgery
- Stroke risk: 26% in 2 years if medical management
Symptomatic moderate ICA stenosis (50-69%) had a 5-year rate of ipsilateral stroke:
- 15.7% surgically treated (CEA)
- 22.2% medically treated
Symptomatic ICA stenosis of <50% no benefit from CEA
- Barnett,HG, et.al.(NASCET Collaborators); Benefit of carotid endarterectomy in
patients with symptomatic moderate or severe stenosis; N Engl J Med. 1998 Nov
12;339(20):1415-25
ICA angioplasty and stenting
 Controversial
 Long term results pending
 More controlled studies
 Surgeon dependent
 Primary advantage is local anesthetic
 Catheter with balloon
 Metal-mesh stent
Treatment – medical intervention
 Prevention of ischemic stroke
 Meta-analysis of randomized 21 trials
 Antiplatelet treatment
o 28% RR reduction – nonfatal stroke
o 16% RR reduction – fatal stroke
- Antithrombotic Trialists Collaboration. Collaborative meta-analysis of randomized
trials of antiplatelet therapy for prevention of death, MI, and stroke in high risk patients.
BMJ 2002; 324:71-86
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