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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
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