What is the scoring system for assessing stroke risk in patients with Transient Ischaemic Attack (TIA)?

ABCD2 Score for Assessing Stroke Risk in TIA Patients

The ABCD2 score is the recommended validated tool for assessing stroke risk in patients with Transient Ischemic Attack (TIA), with scores ≥4 indicating high risk requiring urgent evaluation within 24 hours. 1

Components of the ABCD2 Score

The ABCD2 score assigns points based on five clinical features:

• A: Age ≥60 years (1 point)
• B: Blood pressure ≥140/90 mmHg (1 point)
• C: Clinical features:
  • Unilateral weakness (2 points)
  • Speech impairment without weakness (1 point)
  • Other symptoms (0 points)
• D: Duration of symptoms:
  • ≥60 minutes (2 points)
  • 10-59 minutes (1 point)
  • <10 minutes (0 points)
• D: Diabetes mellitus (1 point)

Maximum total score: 7 points

Risk Stratification Based on ABCD2 Score

• High risk (score 6-7): ~8.1% risk of stroke at 2 days 2
• Moderate risk (score 4-5): ~4.1% risk of stroke at 2 days 2
• Low risk (score 0-3): ~1.0% risk of stroke at 2 days 2

Management Algorithm Based on ABCD2 Score

For ABCD2 Score ≥4 (High Risk):

1. Immediate referral to emergency department with stroke care capabilities 1
2. Urgent brain imaging (CT or MRI) within 24 hours 1
3. Urgent vascular imaging (carotid ultrasound, CTA, or MRA) within 24 hours 1
4. ECG without delay 1
5. Admission to stroke unit or evaluation in specialized TIA clinic within 24 hours 1

For ABCD2 Score <4 (Lower Risk):

1. Brain imaging within 48-72 hours 1
2. Carotid ultrasound (if indicated) within 48-72 hours 1
3. Evaluation in TIA clinic within 7-10 days 1

Clinical Implications

The ABCD2 score has been extensively validated across multiple studies and populations. A multicenter validation study showed that patients with ABCD2 scores >3 had a 7-fold higher 90-day stroke risk (28%) compared to those with scores ≤3 (4%) 3. The score maintains its predictive value for both short-term (7-day) and long-term (up to 10 years) stroke risk 4.

Important Caveats

1. Don't rely solely on ABCD2 score: While highly predictive, the score may not identify all high-risk patients. Some patients with low ABCD2 scores may have other high-risk features such as atrial fibrillation or significant carotid stenosis 5.

2. Rapid assessment is crucial: Studies have shown that immediate evaluation and treatment in specialized centers can reduce the relative risk of subsequent stroke by up to 80% 1.

3. Consider additional risk factors: The predictive value improves when used in conjunction with clinical information, vascular imaging, and brain imaging data 6.

4. Recognize limitations: The diagnostic accuracy of the score is secondary to its prognostic value; its primary significance is for short-term prognostic purposes 6.

The implementation of rapid TIA assessment services using the ABCD2 score has significantly reduced stroke recurrence rates, with modern cohorts showing much lower rates than historical controls (1.5%, 2.1%, 2.8%, 3.7%, and 5.1% at days 2,7,30,90, and 365, respectively) 1.