Transient Ischemic Attack (TIA): The Calm Before the Storm

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Transient Ischemic Attack (TIA) The Calm Before
the Storm

• Raymond Reichwein, M.D.
• Associate Professor of Neurology
• Penn State University College of Medicine
• Milton S. Hershey Medical Center
• January 8, 2009

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Disclosures

• Boehringer Ingelheim
• Genentech
• AGA Medical Corp

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OBJECTIVES

• Discuss the importance of TIA and future stroke
  risk.
• Discuss optimal TIA evaluation and management.
• Briefly discuss future stroke prevention, from
  both an antiplatelet/anticoagulant therapy and
  risk factor management standpoint.

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Stroke in the US

• 730,000 new or recurrent strokes each year1
• 167,366 deaths in 1999 (1 of every 14.3 deaths)2
• 4,600,000 stroke survivors alive today2
• Origin of strokes3
• 80 ischemic
• 20 hemorrhagic

1. Broderick J et al. Stroke. 199829415-421.2.
American Heart Association. 2002 Heart and Stroke
Statistical Update. 2001. 3. Pulsinelli WA.
Cerebrovascular diseases. Cecil Textbook of
Medicine. 1996.
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TIA

• Underrecognized
• Underreported
• Undertreated

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TIA Knowledge

• Among 10,112 participants
• 8.2 correctly related the definition of TIA
• 8.6 could identify a typical symptom
• Men, non-whites, and those with lower income and
  fewer years of education were less likely to be
  knowledgeable about TIA.
• Johnston, et al, Neurology 2003

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TIA Definition

• Resolution of acute neurological/stroke deficits
  within 24 hours.
• No imagable acute ischemic stroke changes.

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TIAs

• The majority of TIAs resolve within 60 minutes,
  and most resolve within 30 minutes.
• Less than 15 chance of complete resolution of
  symptoms if last gt1 hour (Levy).
• NINDS IV t-PA trial data revealed only 2 chance
  of complete symptom resolution _at_ 24 hours, for
  neurological symptoms/deficits that didnt
  completely resolve within 1 hour or rapidly
  improve within 3 hours.

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TIA Epidemiology

• gt200,000 events per year (compared to gt730,000
  strokes per year).
• Approximately 10-20 of patients will experience
  a stroke after a TIA within the first 90 days,
  and in approx. 50 of these patients, the stroke
  occurs in the first 24-48 hours.
• Factors associated with increased stroke risk
  advanced age, diabetes mellitus, symptoms more
  than 10 minutes, weakness, and impaired speech.
  Large artery atherothrombotic disease more likely
  to present with a TIA before a stroke, versus
  other etiologies.

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TIA Epidemiology

• Several recent studies reveal a gt10 stroke risk
  in the 90 days after a TIA.
• The risk of stroke within the first 48 hours
  after TIA is approximately 5 (greater than MI
  risk after presenting with acute chest pain
  syndrome).
• Blacks and men had higher stroke risk.

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Event Risk Within 3 MonthsAfter TIA
12.7
10.5
Event Rate
2.6
2.6
Cardiac Event
Recurrent TIA
Stroke
Death
Johnston SC, et al. JAMA. 200028429012906.
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TIA before Stroke by Subtype

• Large-artery atherothrombotic disease 25-50.
• Cardioembolic sources 10-30.
• Small vessel/lacunar disease 10-15.

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Symptomatic Internal Carotid Artery Disease

• NASCET Medical Arm Data (600 patients)
• Two-day risk was 5.5.
• 90-day ipsilateral stroke risk was 20.
• Degree of stenosis (gt70 stenosis) didnt confer
  increased stroke risk.
• Infarct on brain imaging and presence of
  intracranial major-artery disease doubled the
  early stroke risk.
• Benefit from CEA declines rapidly over several
  weeks, particularly in women (Oxford data).

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Cumulative Risk of Stroke
Post-TIA ()
Post-Stroke ()
3 10 5 14 25 40
4 8 12 13 24 29
30 days 1 year 5 years
Sacco. Neurology. 199749(suppl 4)S39. Feinberg
et al. Stroke. 1994251320.
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TIA and ischemic stroke pathophysiology are the
same.The only difference is transient versus
persistent neurological deficits. Certainly,
a TIA state is a much better clinical state to
intervene and prevent a future disabling stroke.

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Risk Factors for First Ischemic Stroke
Modifiable (value established)
Nonmodifiable

• Hypertension
• Atrial fibrillation
• Cigarette smoking
• Hypercholesterolemia
• Heavy alcohol use
• Asymptomatic carotid stenosis
• Transient ischemic attack

• Age
• Gender
• Race/Ethnic
• Heredity

Adapted from Sacco RL. Neurology 199851(suppl
3)S27-S30.
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Stroke in Young Individuals

• Clotting disorders
• Migraine
• Birth control pills
• Illicit drug use
• Arterial dissection
• Patent foramen ovale
• Autoimmune disorders (lupus)

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TIA Evaluation

• Prompt evaluation and intervention is the key.
• Most TIA patients should be admitted for
  diagnostic evaluation and management (Observation
  unit or equivalent) often significant delay if
  done as outpatient.
• TIA and ischemic stroke diagnostic evaluations
  should be the same.

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Who should be admitted??

• Anyone with no prior/recent TIA/stroke diagnostic
  workup new suspected etiology despite prior
  workup.
• Suspected large vessel (anterior or posterior
  circulation) events.
• Most suspected lacunar/small vessel events,
  particularly if no prior workup (? calm before
  the storm).
• Recurrent/crescendo TIAs.

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ABCD2 Score

• Age 60 or older 1 point
• Blood pressure gt140/90 1 point
• Clinical
• - Unilateral weakness 2 points
• - Speech impairment 1 point
• Duration
• - 60 minutes or more 2 points
• - Less than 60 minutes 1 point
• Diabetes 1 point

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ABCD2 Score

• Score 4 or greater admit to hospital
  (moderate-high stroke risk).
• Score predicted risk similarly among all ethnic
  backgrounds.
• Best predictor of 2, 7, and 90 day stroke risk
  among validated scales.

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Inpatient TIA Management

• Neurochecks follow blood pressures.
• ? Cardiac telemetry (paroxysmal a. fib).
• ? Intravenous Heparin for suspected high risk TIA
  sources, pending completion of diagnostic
  evaluation.
• Diagnostic evaluation should be completed within
  24 hours make decision regarding admission or
  discharge at that point.
• Potential IV t-PA use for recurrent event (acute
  ischemic stroke) while hospitalized.

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Presumptive TIA/stroke etiology determines
optimal treatment, as well as risk for recurrent
events.
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Stroke Subtypes and Incidence
Hemorrhagic stroke15
Other5
Cryptogenic30
Atherosclerotic cerebrovascular disease 20
Small vessel disease lacunes 25
Cardiogenicembolism20
Ischaemic stroke85
Albers et al. Chest 2004 126 (3 Suppl)
438S512S.
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TIA BRAIN IMAGING

• Prior CT(brain) studies revealed a 15-20
  incidence of cerebral infarction in a vascular
  territory related to the patients
  symptoms/deficits.
• Newer MRI(brain) studies, using
  diffusion-weighted imaging (DWI), reveal approx.
  30-50 acute ischemic stroke findings, and about
  half of these persisted on follow-up imaging.
  Best correlated with prolonged TIA symptoms.

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MRI Diffusion Imaging

• Distinguish new versus old ischemic areas.
• Distinguish new ischemic areas even with clinical
  TIA.
• Differentiate stroke etiology (small vessel vs.
  large vessel embolic sources).

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Acute Embolic Strokes
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Acute Ischemic Stroke