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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
Disclosures
• Boehringer Ingelheim
• Genentech
• AGA Medical Corp
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.
04/11/23
1. Broderick J et al. Stroke. 1998;29:415-421.2. American Heart Association. 2002 Heart and Stroke Statistical Update. 2001.3. Pulsinelli WA. Cerebrovascular diseases. Cecil Textbook of Medicine. 1996.
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
TIA
• Underrecognized
• Underreported
• Undertreated
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
TIA Definition
• Resolution of acute neurological/stroke deficits within 24 hours.
• No imagable acute ischemic stroke changes.
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 >1 hour (Levy).
• NINDS IV t-PA trial data revealed only 2% chance of complete symptom resolution @ 24 hours, for neurological symptoms/deficits that didn’t completely resolve within 1 hour or rapidly improve within 3 hours.
TIA Epidemiology• >200,000 events per year (compared to >730,000
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.
TIA Epidemiology
• Several recent studies reveal a >10% 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.
Event Risk Within 3 MonthsEvent Risk Within 3 MonthsAfter TIAAfter TIA
Johnston SC, et al. JAMA. 2000;284:2901 2906.
RecurrentTIA
Cardiac Event
Stroke Death
Ev
ent
Ra
te
12.7%
2.6% 2.6%
10.5%
5% in
48 h
• age > 60 years
• diabetes mellitus
• duration of episode greater than 10 min
• weakness and speech impairment with the episode
Independent risk factors for stroke within 90 days
after TIA:
TIA before Stroke by Subtype
• Large-artery atherothrombotic disease: 25-50%.
• Cardioembolic sources: 10-30%.
• Small vessel/lacunar disease: 10-15%.
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 (>70% stenosis) didn’t 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).
Cumulative Risk of Stroke
Post-TIA (%)
4 – 8
12 – 13
24 – 29
30 days
1 year
5 years
Post-Stroke (%)
3 – 10
5 – 14
25 – 40
Sacco. Neurology. 1997;49(suppl 4):S39.Feinberg et al. Stroke. 1994;25:1320.
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.
Risk Factors for First Ischemic Risk Factors for First Ischemic StrokeStroke
Adapted from Sacco RL. Neurology 1998;51(suppl 3):S27-S30.
Hypertension Atrial fibrillation Cigarette smoking Hypercholesterolemia Heavy alcohol use Asymptomatic carotid
stenosis Transient ischemic
attack
Nonmodifiable Modifiable (value established)
Age Gender Race/Ethnic Heredity
Stroke in Young Individuals
• Clotting disorders
• Migraine
• Birth control pills
• Illicit drug use
• Arterial dissection
• Patent foramen ovale
• Autoimmune disorders (lupus)
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.
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.
ABCD2 Score
• Age 60 or older 1 point• Blood pressure >140/90 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
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.
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.
Presumptive TIA/stroke etiology determines optimal treatment, as well as risk for recurrent events.
Stroke Subtypes and Incidence
Albers et al. Chest 2004; 126 (3 Suppl): 438S–512S.
Ischaemic stroke85%
Hemorrhagic stroke15%Other
5%
Cryptogenic30%
Cardiogenicembolism
20%
Small vesseldisease
“lacunes”25%
Atheroscleroticcerebrovascular
disease20%
TIA BRAIN IMAGING
• Prior CT(brain) studies revealed a 15-20% incidence of cerebral infarction in a vascular territory related to the patient’s 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.
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).
Acute Embolic Strokes
Acute Ischemic Stroke
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