Investigations for Stroke and TIAWhat, When and Where(…and Who and Why)

K. Butcher, MD, PhD, FRCP(C)University of AlbertaWMC Health Sciences Centre

Disclosures

Speaker’s Honoraria

Novo Nordisk

Boeringher Ingelheim

Sanofi-Aventis

Servier

Roche

Consultant

Novo Nordisk

Grant-in-AidSalary Award

Grant-in-Aid

Grant-in-AidSalary Award

Grant-in-AidSalary Award

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.

Outline

1. Acute investigations• Imaging• Laboratory/other

2. Secondary prevention investigations

Tempo of investigations in Stroke and TIA

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?

Acute CT Scan

Acute Stroke Treatment: The Need for Speed

Pre-tPA Post-tPA

Time is Brain

The ATLANTIS, ECASS, AND NINDS rt-PA Study group, 2002

Adjusted odds ratio of stroke recovery

Stroke onset to treatment time [min]

N = 2799

4.5 hoursNNT=14

ECASS III Results

Who Needs Imaging?

Patients with Focal CNS

Symptoms and Signs

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

Imaging Triage: Physical ExamThe NIH Stroke Scale: RAPID and directed examination

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

Putting Symptoms into Context

Left sided numbness for 1 houra. 23 year old female with history of migraineb. 52 year old male with history of STEMI 6 weeks ago

IMAGING TEMPO: SUMMARY

FIXED/PERSISTENT CNS DEFICITS

IMAGE IMMEDIATELY

TRANSIENT CNS DEFICITS

IMAGE

WITHIN 24 H

Investigation and Treatment Strategies

Alberta Provincial Stroke Strategy: Telstroke Alberta

Wetaskiwin

Expediting Diagnosis: Tele-Radiology

Future Directions: Portable CT

42 year old F, 2.5 hours of non-fluent dysphasia and Right U/E weakness

CT: Early Infarct Sign

24 hour Follow-up Scan (post r-tPA)

Alberta Stroke Program Early CT Score (ASPECTS)

CT: Early Infarct Sign

Hypo-attenuation: Acute Infarction

Extensive Hypo-attenuation and Sulcal Effacement

24 hour Follow-up Scan (post r-tPA)

Isolated Sulcal Effacement/Swelling

24 hour Follow-up Scan (post r-tPA)

Initial Investiagions: ABC’s

• Airway and Breathing: Oxygen Saturation

Keep Sp02 >92%

Initial Investigations: ABC’sCirculation: 12 lead ECG, cardiac and NIBP

monitor if available

Frequency of Hypertension in Acute Stroke

Adapted from Leonardi-Bee et al, Stroke: 33, 1315, 2002

Hypertensive

Laboratory Investigations

• Glucose (critical…why?)• CBC (Platelets >100 for tPA)• INR, PTT (INR < 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

Imaging Blood Vessels

Hyperdense MCA Sign

Hyperdense Dot Sign

ADVANCED IMAGING

CT Angiography

DWI

CT

T2

Diffusion-Weighted Imaging: DWI

DWI Evolution: Natural History

24 hours

4 hours

Time course of DWI Evolution-11 min +11 min 3 hours 24 hours

Hjort et al, Ann. Neurol, 2005

Value of DWI in Ischemic Stroke

What is the Ischemic Penumbra?

Penumbral Imaging: MRI

No Reperfusion

Reperfusion

Imaging the Penumbra: CT Perfusion

Non-contrast CT Blood FlowCT Angiogram

Investigations for Secondary Prevention

TIA Investigation: Is there a rush?

Gladstone D et al. CMAJ. 2004 Mar 30;170(7):1099-104.

TIA Risk Stratification:ABCD2 Score

A: age > 60 years – 1 point

B: BP (systolic>140mmHg, diastolic>90 mmHg). Either 1 point. (max 1 point)

C: clinical – unilateral weakness =2, speech only = 1

D: Duration, >60 minutes =2, 10-59 =1, <10 =0

D2: Diabetes=1

Rothwell PM, Lancet 2005; 366:29-36, Johnston, SC, Lancet 2007;369:283-292.

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%

What do they Need?

1. Brain Imaging: CT or MRI

Even brief symptoms cause areas of permanent injury

~50% of all TIA’s are associated with permanent damage, particularly if symptoms last > 1 hour

Kidwell C et al. Stroke 1999; 6:1174-1180.

A. Doppler/Duplex Ultrasound

• Indications?– Symptoms of anterior

circulation ischemia

• Utility?• Tempo?

2. Carotid Imaging

B. Cerebral Angiography

Utility?

Indications?

Risks?

Digital Subtraction (Conventional Catheter) Angiography

C. CT AngiographyIntracranialCT Angiogram

ExtracranialCT Angiogram

D. MR AngiographyExtracranial Intracranial

recent stroke, left hemisphere

Indications for Carotid Endarterctomy?

Why does CEA prevent stroke?

NNT=6

NNT=9

NNT=3

Carotid Endarterectomy Timing

3. Cardiac Investigations

• Who needs an Echo?• What kind do they

need?

Echocardiography OptionsTransthoracic Echocardiogram

Transesophageal Echocardiogram

Echocardiography Summary

TEE

Young patients without stroke risk factors (a

small minority)

TTE

Patients with cardiac disease or other

reasons for investigating

ventricular function

Higher Yield Cardiac Investigation?

Holter Monitor

12

34

1234567

% of Patients with Paroxysmal Atrial Fibrillation (this changes management!)

Number of Infarcts

Secondary Prevention Blood Work

• Fasting Glucose—Management?

• Fasting lipids—LDL 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

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