Patients with transient ischemic attack with ABCD2 <4 can have similar 90-day stroke risk as patients with transient ischemic attack with ABCD2 ≥4.

BACKGROUND AND PURPOSE: It is unclear whether patients with transient ischemic attack with an ABCD(2) score <4 can be safely evaluated within the following week as recommended by some national guidelines rather than in emergency.

METHODS: A total of 1679 patients in the SOS-TIA prospective cohort had a definite or possible transient ischemic attack and had complete information on ABCD(2) score components. They were evaluated and treated as soon as possible in a transient ischemic attack clinic with round-the-clock access, 87% of them within 24 hours of the first call to medical attention. Criteria for emergency treatment were internal carotid or intracranial artery stenosis ≥50% or major cardiac source of embolism.

RESULTS: Primary end point was stroke at 90 days. The 90-day stroke rate (number of events/number of patients) was 3.4% (24/701) in patients with ABCD(2) score ≥4, 3.9% (7/180) in patients with ABCD(2) score <4 and criteria for emergency treatment, and 0.4% (3/798) in patients with ABCD(2) score <4 and no criteria for emergency treatment (P for between-group comparison <0.0001).

CONCLUSIONS: When possible, patients with transient ischemic attack should be evaluated without delay regardless of ABCD(2) score because some with lower scores have treatable causes associated with higher short-term risks of stroke.