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					    High Risk TIA:

Identification and Management

        Carolyn Walker RN. BN
            January 2011
                    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
                          What is a TIA?
Definition:
Acute episode of neurologic symptoms lasting < 24 hr

Proposed tissue based definition:
  Rapidly resolving neurologic symptoms, typically
  lasting <1 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)
                 TIA Stroke Risk
Risk of stroke following TIA is high:

   10-20% within 90 days
   50% of these within the first 2 days (48 hours)
                          Johnston et al. JAMA 2000; 284: 2901-06


~ 20%-40% of strokes are preceded by a TIA or non
  disabling stroke
                  (Rothwell et al. Lancet Neurol 2006; 5: 323-331)




 Golden Opportunity for Stroke Prevention!
          Kaplan-Meier Survival-Free from Stroke
Patients Presenting with TIA in Emergency Room (N=1707)




                                                          10.5%



  High risk of stroke during 1st few days after TIA




                                  JAMA 2000;284:2901-2906
Outcomes after TIA Gladstone D et al. CMAJ. 2004 Mar 30;170(7):1099-104.
      18% 3 month readmission rate after TIA
         Speech, motor, >10 min, age >60, diabetes
Are all TIA patients at risk of early
              stroke?



  Is it cost effective to admit all TIA
          patients to hospital?
Is it cost effective to admit all TIA patients to hospital?
                                       NO
    What is the cost of admitting Patients with Transient Ischemic Attack
                                 to hospital?
                   Gordon Gubitz, Stephen Phillips, Victoria Dweyer


 The average cost of in-patient management of TIA was
328,000 Canadian dollars, of which 95% were accounted
for by the cost of the hospital alone.

Ifhospitalization of patients with TIA could be reduced,
significant cost-savings could be realized.
                      Cerebrovascular Diseases 1999; 9: 210-214
We need a strategy to identify those TIA patients
                at Highest Risk
         High Risk TIA: Clinical Predictors
California Score:
Predict 90 day stroke risk
Identified 5 factors associated with high stroke risk
      Age > 60
      Diabetes
      Duration > 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
Clinical Predictors of High Risk TIAs
        Johnston CS et al. JAMA 2000; 284: 2901-6




                            OR                         CI p value
                    Age >60 1.8                     1.3-4.2 0.005
                    DM       2.0                    1.4-2.9 0.001
                    >10 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
    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
       > 10 min < 59 min                                  1
       ≥ 60 min                                           2
Risk: Score < 5 = 0.4% risk; Score of 5 = 16% risk; Score of 6 = 35%
  risk                      Rothwell et al. Lancet; 2005; 366: 29-36
                  ABCD2 Score
          Rothwell et al. Lancet; 2007; 369: 283-292
                                       Yes        No
Age  60 yrs                             1         0
Bp      140/90                          1         0
Clinical Features
 Unilateral weakness                    2         0
 (with or without speech disturbance)
 Speech deficit without weakness       1        0

Duration
     > 10 min < 59 min                  1        0
      60 min                           2        0

Diabetes                                1        0

Score  4 = High Risk
Predictive Value of the ABCD2 progostic score
                 Who is at risk?

Scenario 1:
Seventy year old right-handed man 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.
                  Who is at risk?


Age 70 (1)
BP 160/80 (1)             Risk = 6% (2 day)
Weakness (2)                     11% (7 day)
65 minutes (2)                   17% (30 day)
Diabetes (1)                     22% (90 day)

ABCD2 score = 7
       High Risk TIA:
   Neurovascular Imaging

 CT   scan


 MRI
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 Dec;34(12):2894-8.
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 Dec;34(12):2894-8
              Neurovascular Imaging: MRI
                      Kidwell C et al. Stroke 1999; 6:1174-1180.
                Couttts SB et al. Annals of Neurology 2005;57:848-854
                               Krol A et al. Stroke 2005

40-60% of TIA pts have evidence of ischemic injury on DWI
Factors predicting positive DWI:
•   Symptoms lasting > 1 hour
•   Motor deficits
                                                                    Even brief symptoms
•   Aphasia                                                            cause areas of
                                                                         permanent
                                                                           injury


If TIA and DWI lesion - higher risk of subsequent stroke
     Alberta Stroke Prevention in TIA’s and
      Mild StRokE (ASPIRE) TIA Triaging
                  Consensus
     •   Urgent triage and assessment of TIA province-
         wide deserves evaluation within Alberta
     •   TIA Triaging algorithm created at Aug 2008
         meeting
     •   Facilitate urgent access using a TIA Hotline
     •   Backing of the APSS and the Educational
         Strategy of the APSS
     •   Pocket cards have been produced
22
Once High Risk TIA Identified…
         then what?



  TIA MANAGEMENT
Express Study
SOS - TIA
Evaluate the Event: Investigations

   CT or MRI
        Rule out mimics, identify stroke type
   Carotid Imaging (carotid duplex, CTA or MRA)
        Identify stenosis
   ECG
      ? Cardiac cause - afib
      Holter monitor

   Echocardiogram
        If suspect cardiac cause
   Labs - CBC, lytes, Cr, gluc, PTT, INR, fasting lipids
              TIA Management
There are 2 proven therapies to prevent the
 occurrence of stroke following TIA

   Antiplatelet / Anticoagulation therapy

   Carotid Endarterectomy
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 dypridamal (Aggrenox)
     25mg/200mg OD
Clopidogrel (Plavix)
     75 mg OD, consider loading with 300 mg
Aspirin + Clopidogrel ??????
     ASA 81mg OD + Clopidogrel 75mg OD
          Consider loading dose of each agent
              No evidence to suggest any are superior or inferior to aspirin
Antiplatelet/Anticoagulation Therapy
If cardioembolic source:

   Long-term anticoagulation - Warfarin

       INR acceptable range 2.0 – 3.0 (target 2.5)
Antiplatelet/Anticoagulation Therapy
If cardioembolic source:

   Long-term anticoagulation – Dabigatran
       Dabigatran does not require dose adjustments or
        anticoagulation monitoring.
                           Antiplatelet/Anticoagulation Therapy
      Dabigatran etexilate is a novel, small molecule,
      reversible, direct thrombin inhibitor
      For oral administration


                                                                    CH3
                                   N                              N

                                         N                                     NH
                                                                  N
                          O                   O
        H3C
                               O
                                                                                        O
                                                                      H2N           N
                                                                                            O                                  CH3
                                              Dabigatran etexilate
Stangier J et al British Journal of Clinical Pharmacology 2007, DOI:10.1111/j.1365-
2125.2007.02899. Sorbera LA et al Dabigatran/Dabigatran Etexilate Drugs of the Future
2005; 30 (9): 877-885. Belch S et al. DMB 2007; doi:10.1124/dmb.107.019083              Dabigatran etexilate is in clinical development and not licensed for clinical use in stroke
                                                                                                                                    prevention for patients with atrial fibrillation
       RE-LY®: Randomised Evaluation of Long term
                  anticoagulant therapy

                                               Atrial fibrillation with ≥ 1 risk factor
                                                  Absence of contraindications

RE-LY® – study design
                                                                       R


                        Warfarin
                                                                Dabigatran etexilate                         Dabigatran etexilate
                   1 mg, 3 mg, 5 mg
                                                                    110 mg bid                                   150 mg bid
                      (INR 2.0-3.0)
                                                                      N=6000                                       N=6000
                         N=6000

  Primary objective: To establish the non-inferiority of dabigatran etexilate to warfarin
  Minimum 1 year follow-up, maximum of 3 years and mean of 2 years of follow-up

 Ezekowitz MD, et al. Am Heart J 2009;157:805-10.
 Connolly SJ., et al. NEJM published online on Aug 30th 2009.              Dabigatran etexilate is in clinical development and not licensed for clinical use in
 DOI 10.1056/NEJMoa0905561                                                                                  stroke prevention for patients with atrial fibrillation
Conclusions

 Dabigatran etexilate has shown to concurrently reduce both
    thrombotic and hemorrhagic events

 Both doses of dabigatran provide different and complimentary
    advantages over warfarin

       150 mg BID has superior efficacy with similar bleeding

       110 mg BID has significantly less bleedings with
           similar efficacy

       Similar net clinical benefit was seen between the two dabigatran
           doses


Connolly SJ., et al. NEJM published online on Aug 30th 2009.   Dabigatran etexilate is in clinical development and not licensed for clinical use in
DOI 10.1056/NEJMoa0905561                                                                       stroke prevention for patients with atrial fibrillation
   TIA Management

Carotid Endarterectomy
            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
         Carotid Endarterectomy

If TIA due to ≥ 50% stenosis in extracranial internal
   carotid artery consider CEA



Greatest benefit if surgery within 2 weeks

                          Rothwell et al. Lancet; 2004; 363: 915-25
Early Carotid Surgery Better in 50-69% stenosis




                            NNT 7




               Rothwell PM et al. Stroke 2004;35:2855-2861.
Early Carotid Surgery Much Better >70% w/o near-occlusion
                   Rothwell PM et al. Stroke 2004;35:2855-2861.



                        NNT 3
    Putting it all together


     High Risk TIA:

Identification and Management
To order pocket card: there is a link on APSS webpage underneath
Professional Education Resources:
http://www.strokestrategy.ab.ca/health-care-providers-ed.html:
            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
               Case Scenarios
Time since onset?

ABCD2 score?

What is the risk?

What are you going to do?
                  High Risk

Antiplatelet?

Investigations?

Referrals?
                       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
           Case Scenarios #2
55 year old healthy right-handed female is seen in
  the clinic after an episode of speech difficulty
  three days ago lasting approximately
   15 minutes.

She denies other neurological symptoms. Her
 examination is now completely normal aside for
 a blood pressure of 155/90.
               Case Scenarios
Time since onset?

ABCD2 score?

What is the risk?

What are you going to do?
                  Medium Risk

Antiplatelet?

Investigations?

Stroke Prevention Clinic referral?
Questions?

				
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