High Risk TIA: Identification and Management

1
High Risk TIAIdentification and Management

• April 2008

Information was produced and/or compiled by the
Alberta Provincial Stroke Strategy and written
permission is required prior to reprinting any of
the material located within this document.
04/0804/09R
2
High Risk TIA Identification and Management

• Learning Objectives
• Upon completion of this session, participants
  will be able to
• 1. Identify clinical predictors of stroke
  following a transient ischemic attack
• 2. Describe how neurovascular imaging may assist
  to identify those patients at increased risk of
  stroke following a transient ischemic attack.
• 3. Describe the appropriate management of a
  high risk TIA patient

3
What is a TIA?

• Definition
• Focal neurological deficit lasting lt 24 hr
• Proposed tissue based definition
• Rapidly resolving neurologic symptoms, typically
  lasting lt1 hour, with no evidence of infarction
  on MRI (DWI) (Albers et al. New Engl J Med
  2002 347 1713-1716)
• 40 - 60 of TIA patients have ischemic injury on
  DWI
• (Ay et al. Cerebrovasc Dis 2002 14
  177-186)

4
Stroke Risk

• Risk of stroke following a TIA is high
• 10-20 within 90 days
• 50 of these within the first 48 hours
• 15-20 of stroke patients have a preceding TIA
• Golden Opportunity for Stroke Prevention!

5
TIA Prognosis
TIA Review. Johnston C.
Speech, motor, gt10 min, age gt60, diabetes
6
(No Transcript)
7
TIA Prognosis
Speech, motor, gt10 min, age gt60, diabetes
9.5 at 90 days
14.5 at 1 year
8
Stroke Risk
Gladstone D et al. CMAJ. 2004 Mar
30170(7)1099-104.
Speech, motor, gt10 min, age gt60, diabetes
9
Outcomes after TIA Gladstone D et al. CMAJ. 2004
Mar 30170(7)1099-104.
18 3 month readmission rate after TIA
Speech, motor, gt10 min, age gt60, diabetes
10
Are all TIA patients at risk of early stroke?

• Is it cost effective to admit all TIA patients to
  hospital?

11
Is it cost effective to admit all TIA patients to
hospital? NO

• What is the cost of admitting patients with a TIA
  to hospital?
• Gordon Gubitz, Stephen Phillips, Victoria Dweyer
• The average cost of in-patient management of
  TIAs was 328,000 (Can), of which 95 was
  attributed to the cost of hospitalization alone.
  
• If hospitalization of patients with TIA could be
  reduced, significant cost-savings could be
  realized.

Cerebrovascular Diseases 1999 9 210-214
12
Is it cost effective to admit all TIA patients to
hospital? NO

• Cost utility analysis of 24 hour TIA (based on
  higher likelihood of tPA)
• The overall cost-effectiveness ratio was 55,044
  per quality-adjusted life year
• For patients with higher risk of stroke,
  admission was cost-effective
• Neurology 2005 65 1799-1801

13
We need a strategy to identify those TIA patients
at highest risk
14
High Risk TIA Clinical Predictors

• California Score
• Predict 90 day stroke risk
• Identified 5 factors associated with high stroke
  risk
• Age gt 60
• Diabetes
• Duration gt 10 min
• Weakness
• Speech impairment
• Risk 0 if none of the above factors
• 34 if had all 5 factors
• Johnston et al. JAMA 2000 284 2901-2906

15
Clinical Predictors of High Risk TIAs Johnston
CS et al. JAMA 2000 284 2901-6
OR CI p value Age gt60
1.8 1.3-4.2 0.005 DM 2.0
1.4-2.9 0.001 gt10 min 2.3 1.3-4.2
0.005 Weakness 1.9 1.4-2.6 0.001 Speech
1.5 1.1-2.1 0.01
16
High Risk TIA Clinical PredictorsRecurrent
Sensory Benign Johnston C et al. Neurology
2004622015-2020.
Speech, motor, gt10 min, age gt60, diabetes
Benign recurrent sensory attacks
17
High Risk TIA Clinical Predictors

• ABCD Score
• Predict 7 day stroke risk Identified 4 areas
  associated with high risk
• Points
• Age 60 1
• Blood pressure 140/90 1
• Clinical features
• Unilateral weakness 2
• Speech disturbance without weakness 1
• Duration of symptoms
• gt 10 min lt 59 min 1
• 60 min 2
• Risk Score lt 5 0.4 risk Score of 5 16
  risk Score of 6 35 risk
  Rothwell et al. Lancet 2005 366
  29-36

18
1 1
2 1 0
2 1 0
19
(No Transcript)
20
High Risk TIA Clinical PredictorsABCD2 Score -
Refinement

Lancet 2007 369283-92
21
ABCD2 Score
22
High Risk TIA Clinical Predictors

• TIA Stroke Risk Assessment
• High Risk
• Symptom onset lt 48 hours with ABCD2 score 5
• Medium Risk
• Symptom onset gt 48 hours with ABCD2 score 5
• Symptom onset lt 48 hours with ABCD2 score lt 5
• Low Risk
• System onset gt 48 hours with ABCD2 score lt 5
• Pure sensory deficit
• Pure ataxia

23
Who is at risk?

• Scenario 1
• 70 year old right-handed male with a history of
  diabetes and smoking is seen in the Emergency
  department after an episode three hours
  previously of transient aphasia and right
  hemiparesis lasting 65 minutes. This is his
  second episode in a week. He denies other
  neurologic symptoms. His examination is now
  completely normal, aside from a blood pressure of
  160/80.

24
Who is at risk?

• Age 70 (1)
• BP 160/80 (1)
• Weakness (2)
• 65 minutes (1)
• Diabetes (1)
• ABCD2 score 7

• Risk 6 (2 day)
• 11 (7 day)
• 17 (30 day)
• 22 (90 day)

25
High Risk TIA Neurovascular Imaging

• CT scan
• MRI
• Carotid Imaging

26
Neurovascular Imaging CT Scan

• TIA population 67 CT performed
• 4 (13/322) had evidence of infarct on CT
• Risk of stroke higher among those with a new
  infarct on head CT
• Stroke. 2003
  Dec34(12)2894-8.

27
Kaplan-Meier life-table analysis of survival free
from stroke for patients with (dotted line) and
without (solid line) new infarct on head CT
10
38
stroke 2003 Dec34(12)2894-8
28
Neurovascular Imaging MRIKidwell C et al.
Stroke 1999 61174-1180. Couttts SB et al.
Annals of Neurology 200557848-854Krol A et al.
Stroke 2005

• 40-60 of TIA pts have evidence of ischemic
  injury on DWI
• Factors predicting positive DWI
• Symptoms lasting gt 1 hour
• Motor deficits
• Aphasia
• If TIA and DWI lesion - higher risk of subsequent
  stroke

Even brief symptoms cause areas of permanent
injury
29
Neurovascular Imaging Carotid Imaging

• Imaging carotids is an important part of TIA
  evaluation
• Carotid doppler ultrasound
• CT angiography (CTA)
• Magnetic resonance angiography
• There is an increased stroke risk with carotid
  artery disease

30
Once High Risk TIA Identifiedthen what?

• TIA MANAGEMENT

31
TIA Management

• There are 2 proven therapies to prevent the
  occurrence of stroke following TIA
• Antiplatelet / Anticoagulation therapy
• Carotid Endarterectomy

32
Antiplatelet/Anticoagulation Therapy

• Aspirin (50-325 mg/day) is first line treatment
• If aspirin naïve- load with 160mg then 81 mg OD
• Options
• Aspirin/extended release dipyridamole (Aggrenox)
• 25mg/200mg BID
• Clopidogrel (Plavix)
• 75 mg OD, consider loading with 300 mg
• No evidence to suggest any are superior or
  inferior to aspirin

33
Results
Cumulative Event Rate (Ischemic Stroke,
Myocardial Infarction, Vascular Death,
Rehospitalization due to Ischemic Event)
Placeboclopidogrel
6.4 RRR 1.03 ARR p0.244
ASAclopidogrel
Cumulative event rate ()
On-Treatment Analysis 9.6 RRR, 1.6 ARR, p0.10
0
1
3
6
12
18
Months of follow-up
All patients received clopidogrel background
therapy
34
Antiplatelet/Anticoagulation Therapy

• If cardioembolic source
• Long-term anticoagulation
• INR acceptable range 2.0 3.0 (target 2.5)

35
TIA Management Carotid Endarterectomy
36
Carotid Endarterectomy

• If TIA due to 50 stenosis in extracranial
  carotid artery consider CEA
• Greatest benefit if surgery within 2 weeks
• Rothwell et al. Lancet 2004 363 915-25

37
Carotid Artery DiseaseBenefit of CEA

• Carotid endarterectomy medical management vs
  medical management alone
• symptomatic patients
• 70 to 99 Carotid stenosis
• 50 to 69 carotid stenosis
• lt50 Carotid stenosis
• asymptomatic patients
• gt or 50
• gtor60

• NNT (Number-Needed-to-Treat)
• 8 to save 1 stroke at 2 years
• 20 to save 1 stroke at 2 years
• 67 to save 1 stroke at 2 years
• 83 to save 1 stroke at 2 years
• 48 to save 1 stroke at 2 years

Rothwell The Lancet vol 361. Jan 11, 2003
38
Early Carotid Surgery Better in 50-69 stenosis
NNT 7
Rothwell PM et al. Stroke 2004352855-2861.
39
Early Carotid Surgery Much Better gt70 w/o
near-occlusion
Rothwell PM et al. Stroke 2004352855-2861.
NNT 3
40
Putting it all together

• High Risk TIA
• Identification and Management

41
Case Scenarios 1
70 year old male Episode of right sided
weakness and impaired speech lasting about 60
minutes yesterday Risk factors hypertension,
high cholesterol, ex-smoker Exam normal

42
Case Scenarios
ABCD2 score? Time since onset? What is
the risk? What are you going to do?

43
What is the risk? What are you going to do?

• Low risk investigate later
• Medium risk investigate soon
• High risk consider immediate investigation/admiss
  ion
• Very high risk admission with aggressive
  treatment
• Extreme risk HELP!

44
ER Guidelines
Vital signs (NIHSS) ECG CT
scan Antiplatelet Carotid dopplar U/S

45
Case Scenarios
70 year old male Episode of right sided
weakness and impaired speech yesterday Risk
factor s Hypertension, high cholesterol,
ex-smoker Exam normal Carotid dopplers 88 L
ICA stenosis

46
Case Scenarios 2

• 55 year old healthy right-handed female is seen
  in a walk-in clinic after an episode of speech
  difficulty three hours previous lasting 15
  minutes.
• She denies other neurological symptoms. Her
  examination is now completely normal aside for a
  blood pressure of 155/90.

47
Case Scenarios

• Age 55 (0)
• BP 155/90 (1)
• Speech (1)
• 15 minutes (1)
• Diabetes (0)
• ABCD2 score 3

• Risk 2 (2 day)
• 2 (7 day)
• 3 (30 day)
• 4 (90 day)

48
Medium Risk
Vital signs ECG CT scan Antiplatelet Caro
tid dopplar U/S Stroke Prevention Clinic referral

49
Questions?
50
High Risk TIA Identification and Management

• Prepared by
• Carolyn Walker, RN, BN
• Education Coordinator
• Alberta Provincial Stroke Strategy
• March 2008
• The APSS would like to acknowledge the
  contributions of Chinook, Capital and Calgary
  Health Regions for information used in the
  development of this presentation.
• April 7, 2008