Background and Purpose—The National Institute for Clinical Excellence (NICE) recommends that patients with a transient ischemic attack and ABCD² score 4 and those with >2 transient ischemic attacks within 1 week be admitted for urgent complete etiologic evaluation within 24 hours and that those with an ABCD² score <4 be evaluated less urgently within 1 week.

Methods—Using data from 1176 patients with a definite or possible transient ischemic attack or minor stroke included in the SOS-TIA registry (January 2003 to June 2007), we studied the usefulness of the conventional ABCD² score cutoff as well as the NICE criteria for urgent admission to a stroke unit defined as presence of symptomatic internal carotid artery stenosis 50%, symptomatic intracranial artery stenosis 50%, or major cardiac source of embolism.

Results—Among 697 patients with an ABCD² score <4, 20% required immediate consideration for emergency treatment (eg, symptomatic internal carotid stenosis 50% in 9.1% of patients, symptomatic intracranial stenosis in 5.0%, atrial fibrillation in 5.9%, other major cardiac source of embolism in 2.1%) in comparison to 31.6% of 497 patients with an ABCD² score 4. The sensitivity and specificity of ABCD² score 4 or NICE criteria for discriminating between patients requiring admission or not were <62% with low positive predictive values (<30%) and high negative predictive values (80%).

Conclusions—One in 5 patients with an ABCD² score <4 had high-risk disease requiring urgent treatment decision-making. When triaging on an ABCD² score, we recommend adding systematic carotid ultrasound (or a default angiographic CT scan) and electrocardiography within 24 hours before postponing complete transient ischemic attack evaluation.