Investigations for Stroke and TIA

1
Investigations for Stroke and TIA What, When and
Where (and Who and Why)
K. Butcher, MD, PhD, FRCP(C) University of
Alberta WMC Health Sciences Centre
2
Disclosures
Grant-in-Aid Salary Award
Grant-in-Aid Salary Award
Grant-in-Aid Salary Award

• Speakers Honoraria
• Novo Nordisk
• Boeringher Ingelheim
• Sanofi-Aventis
• Servier
• Roche

Grant-in-Aid
Consultant Novo Nordisk
3
Learning Objectives

• The requirement for urgent brain imaging in
  patients with new onset focal neurological
  deficits.
• The tempo of brain imaging required in patients
  with suspected TIA versus stroke, and the
  relationship to treatment decisions.
• The available options for brain as well as
  intracranial and extracranial vascular imaging.
  Participants will also appreciate the advantages
  and disadvantages of each imaging modality.
• Appropriateness and timing of various cardiac
  investigations, including ECG, Holter monitoring
  and echocardiography.
• Appropriate blood work to be performed in stroke
  and TIA patients.

4
Outline

• Acute investigations
• Imaging
• Laboratory/other
• Secondary prevention investigations
• Tempo of investigations in Stroke and TIA

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Case

• 58 year old male with a history of hypertension
  and smoking complains of headache to his office
  co-workers. One minute later, he develops left
  sided facial droop and falls to his left.
• EMS is called and he is brought to your ED. BP
  is 190/100, HR is 90 BPM and he is in NSR.
• Investigation of choice?

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Acute CT Scan
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Acute Stroke Treatment The Need for Speed
Pre-tPA
Post-tPA
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Time is Brain
N 2799
Adjusted odds ratio of stroke recovery
4.5 hours NNT14
Stroke onset to treatment time min
The ATLANTIS, ECASS, AND NINDS rt-PA Study group,
2002
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ECASS III Results
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Who Needs Imaging?

• Patients with Focal CNS
• Symptoms and Signs

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Acute Stroke HistoryPrimary goal Stroke or not
stroke?

• Focal neurological deficits
• Weakness
• Speech problems
• Visual symptoms
• Headache
• Vertigo/Dizziness never stroke in isolation
• Sensory changes

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Imaging Triage Physical Exam
The NIH Stroke Scale RAPID and directed
examination
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Planning the Tempo of Investigations

• Establish true time of onset
• Cardiovascular risk factors
• Previous stroke, ischemic heart disease
• Hypertension
• Atrial fibrillation
• Diabetes
• Smoker
• CV medications
• Younger patients
• Mimics Migraine, epilepsy
• Specific mechanism (esp. younger patients)
  dissection

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Putting Symptoms into Context

• Left sided numbness for 1 hour
• 23 year old female with history of migraine
• 52 year old male with history of STEMI 6 weeks
  ago

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IMAGING TEMPO SUMMARY

• FIXED/PERSISTENT CNS DEFICITS
• IMAGE IMMEDIATELY

• TRANSIENT CNS DEFICITS
• IMAGE
• WITHIN 24 H

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Investigation and Treatment Strategies
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Alberta Provincial Stroke Strategy Telstroke
Alberta
Wetaskiwin
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Expediting Diagnosis Tele-Radiology
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Future Directions Portable CT
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CT Early Infarct Sign
42 year old F, 2.5 hours of non-fluent dysphasia
and Right U/E weakness
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24 hour Follow-up Scan (post r-tPA)
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Alberta Stroke Program Early CT Score (ASPECTS)
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CT Early Infarct Sign
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Hypo-attenuation Acute Infarction
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Extensive Hypo-attenuation and Sulcal Effacement
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24 hour Follow-up Scan (post r-tPA)
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Isolated Sulcal Effacement/Swelling
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24 hour Follow-up Scan (post r-tPA)
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Initial Investiagions ABCs

• Airway and Breathing Oxygen Saturation
• Keep Sp02 gt92

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Initial Investigations ABCs

• Circulation 12 lead ECG, cardiac and NIBP
  monitor if available

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Frequency of Hypertension in Acute Stroke
Hypertensive
Adapted from Leonardi-Bee et al, Stroke 33,
1315, 2002
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Laboratory Investigations

• Glucose (criticalwhy?)
• CBC (Platelets gt100 for tPA)
• INR, PTT (INR lt 1.7 for tPA)
• Lytes, Cr, BUN
• In thrombolysis, the utility of waiting for these
  labs must be weighed against the time is brain
  concept

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Imaging Blood Vessels
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Hyperdense MCA Sign
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Hyperdense Dot Sign
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ADVANCED IMAGING
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CT Angiography
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Diffusion-Weighted Imaging DWI
CT
T2
DWI
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DWI Evolution Natural History
4 hours
24 hours
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Time course of DWI Evolution
-11 min 11 min 3 hours 24 hours
Hjort et al, Ann. Neurol, 2005
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Value of DWI in Ischemic Stroke
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What is the Ischemic Penumbra?
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Penumbral Imaging MRI
No Reperfusion
Reperfusion
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Imaging the Penumbra CT Perfusion
Non-contrast CT
CT Angiogram
Blood Flow
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Investigations for Secondary Prevention
46
TIA Investigation Is there a rush?
Gladstone D et al. CMAJ. 2004 Mar
30170(7)1099-104.
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TIA Risk StratificationABCD2 Score

• A age gt 60 years 1 point
• B BP (systolicgt140mmHg, diastolicgt90 mmHg).
  Either 1 point. (max 1 point)
• C clinical unilateral weakness 2, speech only
  1
• D Duration, gt60 minutes 2, 10-59 1, lt10 0
• D2 Diabetes1

Rothwell PM, Lancet 2005 36629-36, Johnston,
SC, Lancet 2007369283-292.
48
ABCD 2 score Front-loaded Risks

• Score 2-day risk
  7day risk 90 day risk
• High risk 6-7 8.1
  11.7 17.8
• Moderate risk 4-5 4.1
  5.9 9.8
• Low risk 0-3 1.0
  1.2 3.1

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What do they Need?
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1. Brain Imaging CT or MRI
Even brief symptoms cause areas of permanent
injury 50 of all TIAs are associated
with permanent damage, particularly if symptoms
last gt 1 hour
Kidwell C et al. Stroke 1999 61174-1180.
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A. Doppler/Duplex Ultrasound
2. Carotid Imaging

• Indications?
• Symptoms of anterior circulation ischemia
• Utility?
• Tempo?

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B. Cerebral Angiography
Digital Subtraction (Conventional Catheter)
Angiography
Utility? Indications? Risks?
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C. CT Angiography
Intracranial CT Angiogram
Extracranial CT Angiogram
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D. MR Angiography
Extracranial
Intracranial
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Indications for Carotid Endarterctomy?
Why does CEA prevent stroke?
recent stroke, left hemisphere
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Carotid Endarterectomy Timing
NNT3
NNT6
NNT9
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3. Cardiac Investigations

• Who needs an Echo?
• What kind do they need?

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Echocardiography Options
Transthoracic Echocardiogram
Transesophageal Echocardiogram
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Echocardiography Summary

• TEE
• Young patients without stroke risk factors (a
  small minority)

• TTE
• Patients with cardiac disease or other reasons
  for investigating ventricular function

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Higher Yield Cardiac Investigation?
of Patients with Paroxysmal Atrial Fibrillation
(this changes management!)

• Holter Monitor

Number of Infarcts
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Secondary Prevention Blood Work

• Fasting GlucoseManagement?
• Fasting lipidsLDL target?
• Homocysteine?
• Tests of Hypercoagulability?
• Reserve for younger patients or those with a
  history of recurrent thrombosis
• Anticardiolipin and Lupus Anticoagulant are the
  higher yield investigations

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Summary

• Diagnosis
• rapid, accurate diagnosis essential Time is
  Brain
• History and Physical identify focal neurological
  deficits
• Acute Treatment
• Consider thrombolysis
• TIA is also a medical emergency and needs to be
  investigated urgently