Ischemic Posterior Circulation Stroke Christopher Lewandowski, M.D. Residency Program Director Department of Emergency Medicine Henry Ford Hospital, Detroit, MI Sunitha Santhakumar, M.D. Department of Emergency Medicine Henry Ford Hospital,

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Ischemic Posterior Circulation Stroke
Christopher Lewandowski, M.D.Residency Program
Director Department of Emergency Medicine Henry
Ford Hospital, Detroit, MI Sunitha Santhakumar,
M.D. Department of Emergency Medicine Henry
Ford Hospital, Detroit, MI
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Case Study

• HPI
• The patient is 41 y.o. male, with a past history
  of alcohol abuse, hypertension who presents to
  the ED with a chief complaint of right -sided
  weakness, slurred speech, and loss of balance.
• The symptoms began 90 minutes prior to arrival.

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Case Study

• PMHx
• Alcohol Abuse, quit for 3 years
• Hypertension
• Seizures, Generalized, none for past 7 years
• Medications
• Dyazide
• Social Hx
• Smoking- 2 pack per day
• ROS Mild dizzy spells for the past 2 weeks,
  each lasting 5-10 minutes

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Case Study

• Physical Exam
• BP- 149/79, P-100, RR-18, T-36.9
• AOx3 on presentation, later became stuporous
• CN dysarthria, pupils R 3.5/ L 3.0 reactive
• L facial droop, gaze palsy to the L
• Motor R arm and R leg weakness (3/5)
• Sensory Decreased to light touch and pinprick on
  R
• Coordination dysmetria on R (not out of
  proportion to weakness)
• NIH Stroke Scale score 14

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What does this patient have?

• Differential Diagnosis
• Stroke
• Intracerebral Hemorrhage
• Tumor
• VBI
• Migraine
• Seizure

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Epidemiology

• Stroke - leading cause of adult disability in the
  USA
• 20 of strokes involve the vertebrobasilar
  arteries
• 20 of global cerebral blood flow is
  vertebrobasilar
• Vertebrobasilar ischemia ranges from intermittent
  vascular insufficiency (VBI) to total basilar
  artery occlusion (BAO)
• 20 - 60 with unfavorable outcome
• Overall mortality 4, BAO - 90 mortality

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Risk Factors Uncontrollable

• Age
• Stroke risk doubles for every decade over 55
• Gender, Males - 1.3 x
• Males have a higher risk, but females live
  longer, therefore there are more female stroke
  survivors
• Heredity
• African Americans - 2x
• Family History
• Previous stroke or TIA - 10x
• Diabetes - 3x (even if well controlled)

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Risk Factors Controllable

• Hypertension - 6x (consistently gt140/90)
• Atrial Fibrillation - 6x
• Smoking - 2x
• Hypercholesterolemia gt 200
• Heart Disease - 2x
• Alcohol, (gt 4oz/day)
• Obesity
• BMI gt 30
• 35 inch waist in women, 40 inches in men

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Risk Factors Vertebrobasilar Ischemia

• Risk factors for the Posterior circulation are
  the same as for the anterior circulation
• Hypertension, diabetes mellitus, hyperlipidemia,
  and tobacco are especially important for the
  posterior circulation

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Posterior Circulation Stroke Anatomy
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Posterior Circulation Stroke Anatomy
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Pathology

• Atherosclerosis
• In situ thrombosis
• Often complete occlusion
• 90 mortality
• Embolization (20-50)
• Heart or proximal vessels
• May cause VBI
• Good prognosis

• Subclavian steal syndrome
• Symptoms brought on by arm exercise
• Trauma
• Especially in the young
• Vertebral artery dissection
• Lacunar (small vessel disease)

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Emergency Department Presentation

• Prodrome very common
• 60 of patients with Basilar artery thrombosis
• Stuttering or progressive onset of symptoms
• 2 weeks prior to ED presentation

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Emergency Department Presentation

• Prodromal Symptoms (in order of frequency)
• Vertigo and Nausea (30)
• Headache, Neckache (20)
• Hemiparesis (10)
• Dysarthria, Diplopia (10)
• Hemianopia ( 6)
• Ferbert, Stroke 1990

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Emergency Department Presentation

• Clinical Findings Depends on the syndrome
• Range asymptomatic to comatose
• The 5 Ds Dizziness, Diplopia, Dysarthria,
  Dysphagia, Dystaxia
• Hallmarks Crossed findings
• Cranial nerve deficits - Ipsilateral
• Motor / Sensory deficits - Contralateral

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Vertigo

• Hallucination of movement of the patient or the
  environment, not associated with loss of
  consciousness
• Visual, proprioceptive, and vestibular systems
  maintain position (Romberg test)
• Semicircular canals connect to the vestibular
  nuclei in the brainstem via CN VIII
• Vestibular nuclei connect to the cerebellum, MLF
  (eye movement) and the vestibulospinal tract

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Nystagmus

• Nystagmus means nodding off (as in sleeping
  during this lecture, slow sleep phase with rapid
  correction)
• Nystagmus is named for its fast component
• Medial longitudinal fasciculus coordinates the
  ipsilateral medial rectus (CN III) and the
  contralateral lateral rectus (CN VI)
• Inner ear provides symmetric resting discharge

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Nystagmus

• Loss of input from one side leaves the other side
  unopposed
• Unopposed stimulation causes a slow drift toward
  the diseased side
• Cerebral cortex corrects for slow drift with a
  very rapid return toward a more normal position
• The brainstem can compensate for asymmetric
  peripheral inputs leading to latency, fatigue,
  and habituation

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Vertebrobasilar Ischemia Syndromes

• VBI
• Common term for TIAs of the vertebrobasilar
  system
• Patients often asymptomatic in ED
• Frequent episodes, especially as prodromal sx
• Requires evaluation of etiology
• Very rare to present as vertigo alone
• Difficult to distinguish from other causes of
  dizziness

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Was this Patients Dizziness Central or
Peripheral

• Central Peripheral
• Intensity Mild Severe
• Tinnitis Rare Common
• CN findings Frequent None
• Nystagmus
• Visual fixation No inhibition Inhibits
• Horizontorotary Rare Common
• Latency None 3-40 sec
• Fatigue None yes

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Posterior Circulation Stroke Syndromes

• VBI, brainstem TIAs
• Occur over days-weeks
• Intermittent fluctuating brainstem sx
• Dizziness plus cranial nerve symptoms
• Rarely dizziness alone

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Vertebrobasilar Ischemia Syndromes

• Branch artery occlusions
• Produce a specific stroke syndrome for each
  artery
• Longer and circumfrential arteries
• Small penetrating branches supplying midline
  structures and causing lacunar syndromes
• Characterized by the 5Ds and crossed findings
• The severity of the stroke depends on the
  collateral blood flow and the location of the
  occlusion

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Posterior Circulation Stroke Syndromes
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Vertebrobasilar Ischemia Syndromes

• Basilar artery occlusion
• 75 with prodromal symptoms
• 63 with gradual and progressive onset
• Can produce a locked-in syndrome
• Awake, quadriplegia, bilateral facial and
  oropharyngeal palsy, preserved vertical gaze
• May present comatose if reticular activating
  system is involved

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Emergency Department Diagnosis

• History
• Prodrome
• Dizziness
• Physical Exam,
• Blood pressure in both arms
• Diagnostic Studies
• Blood tests,CXR, EKG
• Imaging

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Emergency Department Diagnosis

• Confirm the Diagnosis (Emergent)
• CT Scan
• MRI, MRA, DWI
• TCD
• Angiography (DSA)

• Evaluation of Stroke Etiology (Inpatient)
• MRA / Angiography
• Echo / TEE
• TCD
• Carotid Doppler

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Emergency Department Evaluation

• CT scan - head, noncontrast
• Necessary to rule out intracerebral hemorrhage
• Most sensitive test for ICH
• Poor for posterior fossa visualization
• Bone artifact
• Can pick up Basilar artery thrombosis
• Highly specific sign, very low sensitivity
• CT Angiography (spiral CT)
• Reliably assesses basilar artery patency,
  inconclusive in patients with advanced arterial
  calcification

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Case Study CT Scan
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Baseline CT scan
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Emergency Department Evaluation

• MRI - long scan times, unavailable, access to
  patient is poor
• Standard MRI, not reliable for ICH in first hours
• Major advantage is Posterior Fossa imaging
• MR Angiography -reliable evaluation of arteries
  for VBI, BAO
• DWI - Diffusion weighted imaging demonstrates
  infarcted tissue, this is not a contraindication
  to thrombolysis

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MRI-DWI in the posterior fossa
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Emergency Department Evaluation

• TCD
• Assesses flow through Vertebrobasilar system
• Limited in BAO
• Patient anatomy, penetration to distal BA
  difficult
• Brandt TCD diagnostic in 7 of 19 patients with
  suspected BAO, 2 of 19 false negatives
• Low sensitivity for BAO, not useful in ED

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Emergency Department Evaluation

• Digital subtraction angiography
• Gold Standard for diagnosis of BAO
• Time consuming, expensive, invasive
• Requires patient cooperation, anesthesia
• Allows for intra-arterial intervention
• Thrombolysis, angioplasty

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Emergency Department Management

• Stabilization
• Ensure oxygenation and ventilation
• Optimize cerebral blood flow by managing the
  blood pressure and hydration carefully, as
  autoregulation lost, ischemic areas become
  perfusion dependant
• Avoid glucose, avoid hypotension, treat fevers
  aggressively
• Evaluate for anticoagulation or thrombolysis

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Emergency Department Management

• Conservative Treatment
• Antiplatelet and Antithrombotic
• Thrombolytic Treatment
• Intravenous within 3 hours symptom onset and
  the patient meets all treatment criteria
• Intra-Arterial Therapy infusion of thrombolytic
  agent into vessel or clot within 24 hours of
  onset of symptoms

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Posterior Circulation Stroke Treatment

• Conservative Treatment
• Antiplatelet and Anti thrombotic Therapy
• Uncontrolled, Retrospective Studies , 1950s
  1960s
• Compared to historical controls, patients treated
  with heparin had lower mortality (8-15 vs.
  40-60)
• Stopped progression of VBI to infarction
• TOAST Trial
• No evidence to support heparinization in acute
  stroke

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Posterior Circulation Stroke Treatment

• Intravenous Thrombolysis
• NINDS rt-PA Acute Stroke Trial
• t-PA approved within 3 hours of symptom onset
• Few posterior circulation strokes

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Posterior Circulation Stroke Treatment

• Intra-arterial Thrombolysis
• No randomized controlled trials completed
• Multiple small series and reports
• Results (Over 200 patients treated)
• Mortality 20-60 , assoc. with lack of
  recanalization
• Favorable outcomes in 25-60
• ICH rate low, 0-15

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Posterior Circulation Stroke Future Treatment

• Intra-arterial Thrombolysis
• Superselective approach, micro-catheters
• Angioplasty
• Angio-jet

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What is the prognosis for this patient ?

• All Posterior Circulation Strokes
• New England Medical Center Posterior Circulation
  Stroke Registry
• Mortality 4
• Minor or no Disability 79
• Locked In Syndrome (Basilar artery occlusion)
• Mortality gt 90
• How do you know if a patient will progress to
  locked-in syndrome ? Observation

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Case Study Outcome

• The patient mental status deteriorated, repeat
  NIH-SS score was 22
• He received intravenous thrombolysis
• He had significant early improvement but without
  complete resolution of symptoms
• On day 4, the NIH - SS score was 10
• MRA L sup. cerebellar art. and RL Ant-Inf
  cerebellar arteries were non-visualized,
• Cardiac evaluation was negative
• He was discharged on Coumadin to Rehab

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Case Study MRI - DWIlt12 Hours
4 Days
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Summary

• Posterior Circulation Strokes are characterized
  by the 5Ds and crossed findings
• Maintain a high index of suspicion for prodromal
  symptoms - vertigo with CN sx
• The locked-in syndrome consists of quadriplegia,
  bilateral facial and oropharyngeal palsy but
  preservation of cortical function and vertical
  gaze

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Summary

• The prognosis for vertebrobasilar ischemia is
  generally good, except for locked-in syndrome
  (basilar artery occlusion)
• Treatment consists of conservative therapy
  (aspirin and heparin) or IV thrombolysis (lt3 hrs)
  or IA thrombolysis (up to 24 hours)

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Question 1

• All of the following are posterior circulation
  syndromes except
• Ipsilateral CN III palsy with contralateral
• hemiplegia
• B) Ipsolateral facial palsy with contralateral
• hemiplegia
• C) Hemiaplegia and hemisensory loss of the face
  arm and leg on one side of the body
• D) Ipsilateral ataxia and Horners with
  contralateral
• loss of pain and temperature sensation

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Question 2

• Locked-in Syndrome consists of
• A) Coma with quadriplegia
• B) Bilateral upper extremity weakness greater
  than lower extremity weakness
• C) Quadriplegia, bilateral facial and
  oropharyngeal palsy but preservation of
  cortical function and vertical gaze
• D) cranial nerve findings contralateral to motor
  and sensory findings

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Question 3

• Vertigo of central origin is
• A)Generally severe and sudden in onset
• B) Is a very common isolated prodromal
  symptom of VBI
• C) Is often associated with tinnitus
• D) Fatigues easily
• E)Is generally associated with cranial nerve
  findings

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Question 4

• Proven therapy for posterior circulation stroke
  includes
• A) Heparin
• B) Low molecular weight heparin
• C) IV thrombolysis
• D) Intra-arterial regional thrombolysis
• E) Intra-arterial local thrombolysis

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Question 5

• Overall mortality for posterior circulation
  strokes is
• A) lt 5
• B) 20
• C) 40
• D) 70
• E) gt 90

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Question 6

• Mortality for Locked-in Syndrome is
• A) lt 5
• B) 20
• C) 40
• D) 70
• E) gt 90