Transient Ischaemic Attack

Geoffrey Cloud

Which of the following have suffered a TIA?

Transient RSW Transient LSW Transient RSW

DWI MR – stroke ‘footprint’

Definition

Sudden onset focal neurological disturbance

lasting <24 hours and which is thought to be

due to vascular cause

But

DWI lesions seen in 13-68%(1/3 of cases with symptoms lasting up to 1 hour, 1/2 of caseslast over 6 hours)

Newer Definitions

Transient episode of neurological dysfunctioncaused by focal brain, retinal or spinal cordischaemia without acute infarction

AHA/ASA Definition 2009

i.e. requires imaging

either way still………..

How common is TIA?

• Uncertain

– under-reported/over diagnosed

• Incidence around 1.1 per 1000 per year in USor 0.66 in OXVASC

• Prevalence of 2.3% US (around 5M)

Is it a TIA? – clinical clues

• Time course of Symptoms

– onset/offset

• Nature of Symptoms

– focal not general, relating to vascular territory

• Quality of Symptoms

– negative not positive

• Associated Symptoms

– atypical

TIA ‘mimics’

• Migraine

• Seizures

• Syncope

• Metabolic disturbance

• SOL

• Other neurological ( Bell’s palsy, TGA,peripheral nerve injury, vertigo)

Does TIA matter?

• 10-15% of TIA cases have a stroke within thenext 3 months

• Half of strokes following TIA occur within48hrs

Stroke risk after TIA

•1707 emergency room

presentations with TIA

•Follow-up 90 days

•180 (10.5%) stroke rate

•91 within first 2 days

Johnston et al 2000 JAMA

Is this TIA patient at risk?

Coull, Lovett and Rothwell, BMJ 2004

ABCD2 algorithm(1) predicts a patient's very early risk of stroke following a TIA.The score is calculated according to 5 important clinical features:

Symbol Clinical feature Criterion Score

A Age >= 60 1

B Blood pressure >= 140/90 mmHg 1

C Clinical features of the TIA unilateral weakness 2

speech disturbance withoutweakness

1

D1 Duration of symptoms >= 60 min 2

10-59 min 1

<10 min 0

D2 Diabetes diagnosed with diabetes? 1

The corresponding 2 day risks for a subsequent stroke are:

ABCD2 score Risk of stroke at 7 days Risk of stoke at 2 days

0-3 1% 1%

4-5 6% 4%

6-7 12% 8%

Reference:

ABCD2 Lancet 2007 Jan 27;369(9558):283-92

Investigating a TIA

• Brain imaging

• Extracranial vessel imaging

• Cardiac rhythm (+/- structure)

• Routine bloods including fasting lipids

Treatment strategies

• Treating modifiable vascular risk factors

• Reducing embolism

– cardiac

– artery to artery

Effect of carotid endarterectomy stratified bytime from last event to randomisation

Ipsilateral ischaemic stroke and operative stroke or death

32.7

16.0

11.2 9.413.8

3.4

0.0 -2.9

-20.0

-10.0

0.0

10.0

20.0

30.0

40.0

50.0

0-2 2-4 4-12 12+

Weeks between symptomatic event and randomisation

AR

R(%

),9

5%

CI

70-99% 50-69%

Lancet 2004; 363: 915-24

National CIA audit June 2011

Implications for Service Organisation

• Specialist service 7/7

• Responsive

– see, investigate and treat

• Neurovascular MDT pathway

No RCTs of different types of TIA service

EXPRESS

Lancet 2007,370,1432 - 1442

Other examples

• SOS TIA Lancet Neurol 2007;6:953–60

– 1085 pts (22% mimics, 5% stroke, 14 possible TIA)

– 90 day stroke rate of 1.6% cf 6.5% predicted byABCD2 score

• Calgary rapid evaluation Can J Neurol Sci.2009

Jul;36(4):450-5

– 90 day stroke risk 5% in rapid evaluation cohort cf10% in standard

National Guidance

• Stroke strategy

• NICE

• ICSWP

• DH ‘vital signs’

Take home messages for TIA

• they are ‘mini-strokes’

• diagnosis is clinical but requires imaging

• risk stratification is important for organisationof services

• warrant urgent investigation and treatment

And don’t forget to mention……..

Transcranial Doppler (TCD) detection of EmbolicSignals

P = 0.0001P = 0.0037

Ipsilateral TIA and strokeIpsilateral stroke

N = 200

Embolic symptoms predict stroke risk

Time (days)

9080706050403020100

Cu

mu

lativ

esu

rviv

alf

ree

of

ipsi

late

rals

tro

ke

1.05

1.00

.95

.90

.85

.80

.75

.70

.65

.60

.55

.50

Time (days)

9080706050403020100

Su

rviv

al

fre

eo

fip

sila

tera

lstr

ok

eo

rT

IA

1.0

1.0

.9

.9

.8

.8

.8

.7

.7

.6

.6

.5

embolic signals

emboli detected

emboli detected

-censored

no emboli

no emboli-censored

MacKinnon and Markus