David Howse MD FRCPC

1
Assessing the Risk of Stroke Following TIAIs it
really as easy as ABCD2?

• David Howse MD FRCPC
• Ontario Regional Stroke Rounds
• Sept 02, 2009

2
Take Home Messages

• TIA carries a significant short term risk of
  stroke
• This risk can be reliably stratified
• The ABCD2 Score identifies most high risk
  patients
• The ABCD2 score does not identify all high risk
  patients
• Evaluation of individual patients remains
  essential

3
The Unstable Plaque
4
Pathological features of Symptomatic Plaques

• Cap rupture
• Intraplaque hemorrhage
• Unstable plaque due to active inflammation
• Can precede symptoms, and persist for weeks or
  months
• Pathological explanation for dimishing risk with
  time

5
What is a TIA?

• The classic definition is clinical
• A sudden, focal, neurologic deficit involving the
  brain or retina,
• Conforms to a specific vascular territory
• Full clinical resolution within 24 hours
• Arbitrary but useful
• Assumption no infarction
• Implication - transientbenign
• Not the benign implication of absence of damage
  and risk

6
TIA Whats Wrong with the Old Definition?

• Now abundant evidence infarction may occur
  despite clinical resolution
• An historical diagnosis no lab criteria
• Other related terms
• Mini-stroke,
• Stroke-in-evolution,
• Reversible Ischemic Neurologic Deficit (RIND)
• Stuttering stroke

7
New Definition of TIA

• Neurological deficit that resolves clinically
  within one hour
• Deficit conforms to a vascular territory
• Imaging studies (esp. DWI) no infarct

Not widely adopted yet. Most articles use old
definition
Albers, Neurology 2002
8
San FranciscoRisk of Stroke Following TIA

• 5 at 48 hours
• 10 at three months
• Five factors were predictors
• Age
• Diabetes
• Duration gt10 min
• Weakness
• Speech Impairment

Johnston SC JAMA 2000
9
Odds Ratio Five TIA Symptoms Predicting Stroke
Johnston JAMA 2000284
10
Risk of Stroke after TIARole of 5 Risk Factors
N1707
11
Risk of Stroke Following TIA
Johnston S et al JAMA 28420002901
12
Ontario 2001Stroke Risk Post TIA
Gladstone D CMAJ 2004
13
Ontario 2001Management Following TIA
Gladstone D CMAJ 2004
14
The Oxfordshire Experience

• Patients with TIA (historical data 1981 to 1986)
• Identified five independent predictors of
  subsequent stroke
• Age /gt60 yr
• Blood pressure gt140/90
• Clinical features
• Unilateral weakness
• Speech disturbance without weakness
• Duration of symptoms
• gt60 min
• Derived and validated a risk score to predict
  stroke in seven days
• Risk of stroke 9.5 at 90 days 15 at one year

Rothwell P Lancet 200536629
15
Risk Factors for stroke within seven days of TIA
based on ABCD ScoreApplied to the OXVASC study
2002-2004 - validated
Event Rate ()
ABCD Score
Rothwell P Lancet 200536629-36
16
Validation And Refinement of the ABCD2 Score

• Analysed the combined results of the California
  and Oxford groups
• Total of 4799 patients
• Evaluated stroke risk at 2, 7, and 90 days

17
The ABCD2 Score Risk of Stroke Following TIA

• A Age gt 60 years One point
• B Blood pressure gt140/90 One point
• C Clinical features
• Hemiparesis Two points (or)
• Dysphasia One point
• (None for sensory symptoms only)
• D1 Duration of symptoms
• gt one hour Two points (or)
• gt 10 minutes One point
• D2 Diabetes One point
• Range 0-7

18
California and Oxford Scores Validated in four
Separate patient sets

• Created a unified score ABCD2
• Overall risks
• 3.9 at 2 days
• 5.5 at 7 days
• 9.2 at 90 days
• to serve as a standard for clinical care and
  public education

19
Risk of Stroke at 2, 7, 30 and 90 Days Following
a TIA Using ABCD2 Score
High Risk
Intermediate Risk
Stroke Risk ()
Low Risk
ABCD2 Score

• Lancet 2007369283-92.

20
Risk of Stroke Following a TIAMeta-Analysis
Wu C Arch Int Med 2007167
21
Does Acute Management of TIA/Minor Stroke Really
Matter? The EXPRESS Trial

• Part of the Oxfordshire Vascular Study
• Epidemiological survey
• 91,000 subjects
• Introduction of Rapid Stroke Assessment program
• Phase 1 2002-2004
• Appointment weekly
• Recommended therapy did not initiate
• Delays
• Phase 2 2004-2006
• No appt - daily
• Therapy initiated in clinic
• A randomized trial was considered unethical

Rothwell Lancet Oct 2007
22
EXPRESS Oxfordshire Stroke Rates Before and
After Rapid TIA Clinic

• Risk of post-TIA stroke
• Historical 1981-1986
• Phase 1 2002-2004
• Phase 2 2004-2007