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  • Arch Neurol. 1995; 52

Transcript

  • 1. Case
    • 74 year old male, recent carotid doppler following episode of dizziness
      • 50-79% right carotid stenosis
    • PMH- coronary artery disease, hypertension, hyperlipidemia
    • Spell consisting of “fuzzy vision”, uncertain if monocular, lasting minutes up to 15 minutes, with associated “tingling left side of face”
  • 2. Questions
    • Is this amaurosis fugax?
    • What is this patient’s risk for stroke?
    • Is carotid endarterectomy indicated in this case?
  • 3. Amaurosis Fugax … and the role of Carotid Endarterectomy COL Beverly Rice Scott MD Neurology and Neuro-ophthalmology Madigan Army Medical Center
  • 4. Outline
    • Definition and etiologies of transient visual loss
    • Clinical features & pathophysiology
    • Evaluation of transient monocular blindness
    • Amaurosis Fugax and Stroke Risk
      • North American Symptomatic Carotid Endarterectomy Trial (NASCET)
    • Spectrum of ocular ischemic syndromes and stroke risk
  • 5. Definition
    • Painless unilateral transient loss of vision, partial or complete, related to retinal arterial microembolization or hypoperfusion
    • “ fleeting darkness or blindness ”
    • Retinal transient ischemic attack (RTIA)
    • transient monocular blindness (TMB)
    • Accounts for 25% of anterior circulation transient ischemic attacks (TIAs).
  • 6. Transient visual loss Amaurosis Fugax Transient Visual Obscuration Binocular Monocular (TMB) Retinal Migraine Cortical Migraine Heart disease Arteritis
  • 7. Etiologies: Transient visual loss
    • Occlusive retinal artery disease
      • Atheroembolic , cardioembolic, arteritic, hematological disorders, congenital, orbital tumor
    • Low retinal artery pressure
      • Ocular ischemia syndrome , arteriovenous fistula, congestive heart failure, anemia
    • Optic disc disease and anomalies
      • Papilledema, Glaucoma, Drusen
    • Vasospasm ( ophthalmic migraine )
    • Miscellaneous
      • Uhthoff’s phenomenon, classic migraine
  • 8. Clinical Features: Symptoms
    • Abrupt or gradual monocular* visual loss, progressing from peripheral toward center of field
      • +/- descending/ ascending shade, partial or complete
      • ‘ looking through fog’
    • Visual disturbance: Dark, foggy, gray, white
    • Minutes (1-5 minutes, occasionally longer); full resolution takes 10-20 minutes
    • Painless
    • Stereotyped
    • Usually occurs in isolation
    • * may be difficult to distinguish monocular from binocular visual loss
  • 9. Clinical Features: Retinal findings
    • Transient retinal ischemia
      • Often normal
      • “ boxcar-ing” (segmentation of blood columns resulting from stasis)
      • Engorgement of veins
      • Swelling of retina
      • Retinal embolus
  • 10. Clinical features: Retinal findings
    • Acute infarction
      • Opaque and gray (early)
      • “bright plaques” of cholesterol or other microemboli; may persist weeks to years
      • Cotton-wool spot
      • Segmental arteriolar mural opacification
      • Optic disc pallor, arteriolar narrowing (late)
  • 11. Hollenhorst Plaque Retina and Vitreous, Basic and Clinical Science Course, AAO 1996
  • 12. Cotton-wool Spot Retina and Vitreous, Basic and Clinical Science Course, AAO 1996
  • 13. Pathophysiology
    • Atheromatous degeneration and stenosis of the cervical carotid arteries
      • Estimated 27% - 67% w/ amaurosis or retinal strokes
    • Retinal emboli
      • Cholesterol crystals
      • Platelet aggregates
      • Fibrin and blood cells
      • Neutral fat
    • Vasospasm
    • Primary thrombosis of retinal arteries does not occur
  • 14. Pathophysiology
    • Microemboli occludes retinal vessels, then fragment and pass into retinal periphery
    • If disaggregation with reconstitution of blood flow does not occur, ischemic damage to the inner retinal layers may be irreversible
  • 15. Branch Retinal Artery Occlusion Retina and Vitreous, Basic and Clinical Science Course, AAO 1996
  • 16. Evaluation: Transient Monocular Blindness
    • Consider disorders with greatest morbidity and most common disorders
      • Consider age, stereotypy of events
    • Physical exam (blood pressure, carotid/cardiac exam)
    • Ophthalmologic Exam
      • Visual acuity, visual fields, relative afferent pupil defect
      • dilated fundus exam (emboli, anomalous discs)
      • Visual fields
    • Electroretinogram – diminished B-wave amplitude
  • 17. Evaluation: Transient Monocular Blindness
    • Under age 40
    • Migraine history, family
    • Echocardiogram w/ bubble
    • CBC, ESR, ANA, antiphospholipid antibodies
    • stop birth control pill
    • stop smoking
    • Over age 40
    • History for giant cell arteritis, polymyalgia, coronary artery disease, stroke & risk factors
    • ESR, Creactive Protein if older than 50)
    • Carotid Doppler
    • Echocardiogram w/ bubble
    • MRA , CT angiography
    • Fluorescein angiogram
    • Carotid angiography
  • 18. Cerebrovascular disease
    • A spectrum of signs, symptoms, and stroke risks
    Asymptomatic Asymptomatic w/ signs of atherosclerotic Cerebrovascular disease Symptomatic Atherosclerotic Cerebrovascular disease Low risk High risk
  • 19. Amaurosis Fugax and Stroke Risk
    • Isn’t if funny that I went blind
    • in the wrong eye”
    • CM Fisher. Transient monocular blindness associated with hemiplegia. Archives Ophthalmology , 1952.
    • What is the relationship of AF and the other ocular ischemic syndromes to the
    • carotid arteries?
  • 20. Amaurosis Fugax (AF) & Stroke Risk
    • Early studies and reports uncontrolled
      • Different populations
      • Causes aggregated
    • Best studied ocular ischemic syndrome
    • Prognosis following AF considered more favorable than TIA, unless severe stenosis
    • Prognosis altered by carotid endarterectomy?
    • Stroke risk estimated 2-4% prior to NASCET
  • 21. Carotid Endarterectomy (CEA): Historical Perspective
    • 1954: CEA introduced
    • 1959-70: Joint Study of Extracranial Arterial Occlusion
      • surgery: 32% stroke risk
      • medical: 39% stroke risk
      • operative M&M of 11.4%
      • CEA benefit if 3% morbidity
    • 1970: 15,000 operations/yr
    • 1980s: 100,000 operations/yr
    Practical Neurology, Vol 4, 2005 .
  • 22. NASCET 1987-1996
    • North American Symptomatic Carotid Endarterectomy Trial (NASCET)
    • 2885 patients enrolled ; TIA/stroke 120 days
      • 1583 patients(54.9%) -- TIA
      • 1302 patients (45%) – nondisabling stroke
    • carotid stenosis; angio confirmed
      • moderate (30-69%) ; severe (70-99%)
    • Established CEA over medical RX in patients with high grade stenosis (>70%)
  • 23. NASCET Cumulative risk for ipsilateral stroke in symptomatic Carotid Endarterectomy trials at 2 years < 50% , CEA not better than ASA (aspirin) 39% 15 6% 16% 22% 50-70% 65% 8 17% 9.0% 26.0% 70-99% Rel Risk Reduction NNT Absolute Difference Surgical Medical
  • 24. NASCET: Amaurosis & Stroke Risk
    • The Risk of Stroke in Patients With First-Ever Retinal vs Hemispheric Transient Ischemic Attacks and High-grade Carotid Stenosis. Archives of Neurology . 1995.
    • Prognosis after Transient Monocular Blindness Associated with Carotid-Artery Stenosis. NEJM . 2001
  • 25. NASCET Medical Subgroup : High grade stenosis
    • 129 patients with first TIA
      • 59 retinal TIAs (RTIAs)
      • 70 with hemispheric TIAs (HTIAs)
    • Characterize the features and course of subgroups with high grade stenosis
    • Compare outcomes with RTIAs to HTIAs
    • Average follow-up: 19months
    Arch Neurol. 1995; 52
  • 26. NASCET Medical Subgroup : High Grade Stenosis
    • HTIAs: older, higher risk factors
    • RTIAs: higher risk for smoking
    • Longer delay for medical treatment for RTIAs (48 days vs 15.2 days )
    • Estimates for stroke risk at 2 years
      • RTIAs 16.6% +/- 5.5%
      • HTIAs 43.5% +/- 6.7%
    Arch Neurol. 1995; 52
  • 27. NASCET Medical Subgroup: Risk Factors w/ High Grade Stenosis 25.7% (15 d) 20.3% (delayed, 48d) Antiplatelet Rx 51.4% 61% Smoking (5yrs) 40.0% 30.5% Hyperlipidemia 15.7% 13.6% Claudication 40% 27.1% Angina 18.6% 6.8% heart attack 21% 17% diabetes 64.3% 59.3% hypertension 70% 59% Male gender 66.9 61.5 Mean age HTIA (n=70) RTIA (n=59)
  • 28. NASCET Medical Subgroup: Outcomes w/ High Grade Stenosis Arch Neurol. 1995; 52 2 1 MI 2 0 Vascular death 1 0 retinal stroke 0 0 Contralateral stroke 2 1 retinal 8 0 major 17 7 Ipsilateral stroke, minor HTIA (n=70) RTIA (n=59)
  • 29. NASCET Surgical Subgroup: Outcomes
    • 328 surgically treated patients
      • 5.8% perioperative stroke
      • 9% 2 year stroke rate
    • 54 surgical treated patients with RTIA
      • 2 minor perioperative strokes (4%)
      • One stroke (2%) 17 months post-op
      • 6.8% stroke risk at 2 years
  • 30. NASCET: Amaurosis & Stroke Risk
    • The Risk of Stroke in Patients With First-Ever Retinal vs Hemispheric Transient Ischemic Attacks and High-grade Carotid Stenosis. Archives of Neurology . 1995.
    • Prognosis after Transient Monocular Blindness Associated with Carotid-Artery Stenosis. NEJM . 2001
  • 31. NASCET Subgroups: Prognosis of TMB (transient monocular blindness)
    • Compared 397 patients with isolated TMB (medical and surgical subgroups) to 829 patients with hemispheric TIAs
    • Compared stroke risk for TMB and HTIAs in patients with high grade stenosis with and without collaterals
    • Identified risk factors for ipsilateral stroke in patients with carotid stenosis > 50%
  • 32. NASCET Subgroups: Prognosis of TMB
    • HTIAs: older, higher risk factors
    • TMB: higher risk for smoking, increased high grade stenosis, higher incidence of collaterals
    • Medically treated TMB had 3 year ipsilateral stroke risk approx ½ HTIA
    • Surgically treated TMB showed 30-day stroke rate ½ of HTIA (3.6% vs 7.4%)
    • Stroke risk increased with degree of carotid stenosis and specific stroke risk factors
  • 33. NASCET Med/Surg Subgroups : Isolated TMB vs TIA NEJM. Vol 345,2001 3.7% 9.3% Near occlusion 16% 31.7% 70-94% 29.8% 30.5% 50-69% 50% 28.5% < 50% Hemispheric TIA (N=829) TMB (N=397) ICA stenosis
  • 34. NASCET Med/Surg Subgroups : Isolated TMB vs TIA *Collateral circulation = filling of the ACA, PComA, or ophthalmic artery NEJM. Vol 345,2001 6.9% 24.2% Collateral Circulation * Hemispheric TIA (N=829) TMB (N=397)
  • 35. NASCET Med/Surg Subgroups : Three year stroke risk
  • 36. NASCET Medical Subgroups : Collaterals & 3 year stroke risk
    • TMB w/ collaterals (N=25) 2.9%
    • HTIAs w/ collaterals (N=30) 16.7%
    • TMB w/o collaterals (N=44) 16.0%
    • HTIAs w/o collaterals (N=69) 44.4%
    NEJM. Vol 345,2001
  • 37. NASCET Med/surg Subgroup : Isolated TMB (N=397)
    • Median # of TMB episodes: 3 (1-7)
        • 5% had >45 episodes
    • Median duration : 4 minutes (1-10min)
        • 5% had episode > 60min
    • No correlation to carotid stenosis
    • 3 year stroke risk (N= 198, medical)
        • 1 episode -- 10.4 %
        • >2 episodes-- 8.2 %
    NEJM. Vol 345,2001
  • 38. NASCET Medical Subgroup : Stroke Risk Factors
    • TMB with > 50% stenosis
      • Age > 75
      • Male sex
      • h/o hemispheric TIA or stroke
      • h/o intermittent claudication
      • Ipsilateral stenosis 80-94%
      • No collaterals on angiography
    NEJM. Vol 345,2001
  • 39. Amaurosis Fugax & Stroke Risk: NASCET findings
    • TMB has high stroke risk if high grade carotid stenosis, though less than HTIAs
    • Higher collaterals improve prognosis
    • Age, gender, h/o stroke/TIA,& claudication may alter stroke risk
    • CEA reduces stroke risk if surgeon has low complication rate
    • Perioperative risk for stroke and death was lower in patients with TMB
  • 40. Spectrum of clinical stroke risk Amaurosis Fugax (2% -?6%) TIA (3.7%) Minor Stroke (6.1%) Major Stroke (9%) Low risk High risk Estimated Annual Stroke Rates Asymptomatic Stenosis (2%) Asymptomatic Bruit (2%) AION BRAO Asymptomatic retinal emboli Acute & Chronic Ocular Ischemic Syndrome
  • 41. Conclusions
    • Amaurosis Fugax is caused by ischemia to the retina, often associated with carotid stenosis, and is a risk factor for stroke
    • Prognosis is better for patients with amaurosis fugax treated both medically and surgically compared to patients with hemispheric TIAs.
    • Amaurosis Fugax should be recognized, with strong consideration for carotid endarterectomy with high grade carotid stenosis, vascular risk factors present, and low complication rate of procedure in your center
  • 42. References
    • Benavente, et al. Prognosis after Transient Monocular Blindness Associated with Carotid Artery Stenosis. NEJM , Vol 345(15), 2001.
    • Easton and Wilterdink. Carotid Endarterectomy: Trials and Tribulations. Ann Neurology . Vol 35.1994.
    • Glaser. Neuro-ophthalmology. 3 rd ed. 1999
    • Mizener, et al. Ocular Ischemic Syndrome. Ophthalmology , Vol 104, 1997.
    • Rizzo. Neuroophthalmologic Disease of the Retina. Neuro-ophthalmology.
  • 43. References
    • Sacco et al. Guidelines for Prevention of Stroke in patients with ischemic stroke or transient ischemic attack. Stroke . Feb 2006.
    • Streifler, et al. The Risk of Stroke in Patients with First-Ever Retinal vs Hemispheric Transient Ischemic Attacks and High-grade Carotid Stenosis. Archives of Neurology, Vol 52(3), 1995.
    • Wilterdink and Easton. Vascular event rates in patients with atherosclerotic cerebrovascular disease. Arch Neurology . Vol 49. 1992