The ABCD ² Score: Stratifying Risk for Stroke After TIA

The score accurately stratifies patients into groups at high, medium, and low risk.

After a transient ischemic attack (TIA), 4% to 20% of patients will have a stroke within the next 90 days — half within 48 hours. Which patients with TIAs are most likely to have early strokes and to merit urgent preventive intervention? Recently, groups in California and the U.K. devised similar scoring systems that accurately predicted stroke risk after TIA (Journal Watch Aug 12 2005). These groups now jointly present a combined system, termed the ABCD² score, which is more accurate than either of the original systems alone.

The seven-point ABCD² score is based on:

• Age (60 years = 1 point)
• Blood pressure at presentation (140/90 mm Hg = 1 point)
• Clinical features (unilateral weakness = 2 points, speech disturbance without weakness = 1 point)
• Duration of symptoms (60 minutes = 2 points, 10–59 minutes = 1 point)
• Diabetes (1 point)

In 4799 patients with TIAs diagnosed by initial treating physicians in clinics, private offices, and emergency departments in California and Oxford, risk for stroke within 2 days of initial presentation was 1.0% in patients with a score of 0–3, 4.1% in those with a score of 4–5, and 8.1% in those with a score of 6–7. Seven-day and 90-day stroke risks also increased with higher scores.

Comment: The ABCD² score appears to identify TIA patients who are at high risk for stroke within several days. But further investigation is necessary to determine the potential benefits and harms of various interventions — for example, hospitalization, carotid imaging, urgent endarterectomy, antiplatelet agents, or statins — for patients with high and low scores.

— Bruce Soloway, MD

Published in Journal Watch General Medicine February 13, 2007

Citation(s):

Johnston SC et al. Validation and refinement of scores to predict very early stroke risk after transient ischaemic attack. Lancet 2007 Jan 27; 369:283-92.