TIA Management:
The ABCD2 Score
About This Topic
Definition
A focal, transient neurological deficit of ischemic origin and of less than 24 hours duration.
1. Focal implies complete or partial involvement of :
· Anterior circulation (anterior or middle cerebral arteries)
· Posterior circulation (vertebrobasilar system)
· Ophthalmic artery (amaurosis fugax).
2. Transient implies a time constraint:
· The majority of events last seconds to minutes.
· 90% of events resolve within 4 hours.
· All events must resolve within 24 hours
3. Ischemic implies vascular insufficiency from thrombosis, embolism or dissection. Infarction may or may not occur. The definition excludes symptoms caused by:
· Seizure
· Neoplasm
· Infection
· Intracranial hemorrhage
· Arrhythmia
· Migraine
· Hypoglycemia
· Cocaine induced vasospasm
Rationale
1. 20-40% of strokes are preceded by a TIA or non-disabling stroke.
2. Stroke very often occurs within days of the initial TIA.
3. The 90 day risk of stroke following TIA is 10.5%. 50% of these strokes occur within the first 48 hours.1
4. A validated scoring system exists to identify TIA patients at particularly high risk of stroke.2 This clinical assessment can be used to triage patients who require emergent investigation and treatment.
5. Patients with TIA are at high risk for subsequent disability or death. Those identified as high risk by clinical criteria require urgent investigation.3 Those felt to be at lower risk should have complete investigation and initiation of treatment within 48 hours if possible.4
6. Early evaluation and initiation of therapy for TIA or minor stroke markedly reduces risk of major stroke at 90 days.5
7. Actual stroke risk varies markedly with risk score (Table).
8. TIA requires the same urgent attention as acute coronary syndrome. The decision in a rural or remote setting is whether investigation and treatment should be immediate (within 3 hours as for acute stroke) or urgent (within 48 hours).
Clinical Assessment
The
ABCD2 Stroke Score2
|
Parameter |
Points |
|
Age |
|
|
60 + years |
1 |
|
Blood Pressure |
|
|
Systolic 140+ and/or |
1 |
|
Diastolic 90+ |
|
|
Clinical Features |
|
|
Unilateral weakness |
2 |
|
Speech disturbance without weakness |
1 |
|
Duration of symptoms |
|
|
60+ minutes |
2 |
|
10-59 minutes |
1 |
|
< 10 minutes |
0 |
|
Diabetes |
|
|
Yes |
1 |
Risk of stroke within 2 days of TIA is
· 8.1% for score of 6-7
· 4.1% for score of 4-5
· 1.0% for score of 0-3
Stroke
Risk at 2, 7 and 90 Days
According to ABCD2
Score
|
ABCD2 Score |
2-Day |
7-Day |
90-Day |
|
<4 |
1.0% |
1.2% |
3.1% |
|
4 to 5 |
4.1% |
5.9% |
9.8% |
|
>5 |
8.1% |
11.7% |
17.8% |
1. CT scan without enhancement should be done in all patients to exclude other causes of neurological deficit (e.g. hemorrhage, subdural hematoma)
· The presence of an infarct on CT is highly predictive of subsequent stroke
· Early CT showing hemorrhage makes carotid imaging unnecessary.
2. Carotid imaging should be done for all patients with symptoms in anterior circulation territory.6
· The presence of carotid disease is highly predictive of recurrent stroke.
· Consider CT angiogram if Carotid Ultrasound cannot be obtained in reasonable time.4
3. ECG and occasionally Holter monitoring to detect atrial fibrillation.
4. ECHO cardiogram for persons with suspect underlying cardiac abnormalities.
5. Blood sugar to detect extremes in glucose levels.
Immediate
Therapy for Lowering Early Stroke Risk after TIA (secondary stroke prevention)
· ABCD2 score of 4 or more should undergo immediate consultation to consider rapid investigation. For rural areas this may involve rapid transfer for CT and possible thrombolysis if symptoms are slow to resolve.
· ABCD2 score of 0-3 should still be referred for urgent investigations within 24-48 hours if possible to enable institution of early secondary prevention measures.
· Stroke risk is highest in the first 48 hours (Table). All patients should consider temporary 2-day relocation with a caregiver to an area where CT and tPA are available.
2. Anti-platelet therapy. There is good evidence for safety of therapy prior to CT.7
·
ASA 325 mg. chewed stat, then 81 mg daily extended
release daily or
· ASA 25 mg/Dipyridamole 200 mg. 1 bid. Superior to ASA alone (NNT 104 8). Intolerance due to headache is common 9. Expense and headache sometimes influence compliance. Best avoided in unstable angina.
· Clopidogrel 300 mg. stat, then 75 mg. daily can be used in presence of known cardiac disease (without ASA) 10
3. Warfarin anticoagulation for patients in atrial fibrillation. Antiplatelet agents not used.
4. Hypertension management if systolic BP over 220 or diastolic BP above 110
· Watch for worsening neurological deficit if BP lowered excessively.
· Captopril SL 6.25-12.5 mg. q 15 min. prn to maximum dose of 100 mg in 8 hours.
· Hydralazine 10-20 mg. IV q 15 min prn to maximum dose of 400 mg. in 24 hours.
· Maintain BP below 220/110, or 185/110 post thrombolysis.
5. Statin beginning on day 1 - atorvastatin 20 mg.
· Immediate anti-inflammatory benefit 10.
· Continued subsequently in dose sufficient to lower LDL-C to <2
6. Carotid endarterectomy within 2 wk. for anterior circulation TIA with corresponding carotid stenosis > 50%.11
7. Continuation of control of other risk factors:
· smoking
· hypertension
· diabetes
· obesity
· inactivity
References
3. Dean N. Transient ischemic attack: High risk but treatable. Perspectives in Cardiology 2008; 24(1): 32-35.
4. Draft
Guidelines for Use of Stroke/TIA Clinical Pathway.
5. Rothwell PM, Giles MF, Chandratheva A, et al. Effect of urgent treatment of transient ischaemic attack and minor stroke on early recurrent stroke (EXPRESS study). Lancet 2007; 370(9596):1432-1442.
6. Eliasziw M, Kennedy J, Hill MD, et al. Early risk of stroke after a TIA in patients with internal carotid artery disease. CMAJ 2004; 170(7): 1105-1109.
7. Sandercock
P, Gubitz G, Foley P, Counsell C. Antiplatelet therapy for acute ischaemic
stroke (Cochrane Review). In: The Cochrane Library, Issue 3, 2004.
8. Halkes PH, van Gijn J, Kappelle LJ, Koudstaal
PJ, Algra A. Aspirin plus dipyridamole versus aspirin alone after cerebral
ischaemia of arterial origin (ESPRIT): randomised controlled trial. Lancet.
2006;367:1665-73.
9. Adams
RJ, et al. Update to the AHA/ASA
recommendations for the prevention of stroke in patients with stroke and
transient ischemic attack. Stroke 2008;
39: 1647-1652.
10. Misulis KE. Neurologic pearls and nuggets. [audio program]. Audo-Digest Family Practice 2008; 56(18). Available at: www.audio-digest.org (Accessed 2008 Nov. 3)
11. Rothwell PM, Eliasziw M, et al. Sex difference in the effect of time from symptom to surgery on benefit from carotid endarterectomy for transient ischemic attack and non-disabling stroke. Stroke 2004; 35(12): 2855-2861.