Lit Matters #2 - The Canadian TIA Score vs ABCD2/ABCD2i

Transient ischemic attack is a time-sensitive stroke warning, but not all TIA risk scores separate low-risk patients well enough to guide disposition. The Canadian TIA Score outperformed ABCD2 and ABCD2i in suspected TIA, with the real-world value hinging on local access to rapid imaging and neurology follow-up.

TIA Risk Stratification

• Canadian score performance: The Canadian TIA Score provided better 7-day stroke discrimination than ABCD2 or ABCD2i, with an AUC of 0.70 versus 0.60 and 0.64.
• Useful low-risk group: Unlike ABCD2 and ABCD2i, the Canadian score identified a genuinely low-risk cohort, classifying 16.3% of patients into a group with a 7-day event rate at or below 0.5%.
• Middle-category problem: ABCD2 and ABCD2i pushed nearly everyone into a medium-risk bucket, leaving only 3% to 7% outside that zone and limiting bedside usefulness for disposition decisions.
• Risk range across scores: The Canadian TIA Score spans from -3 to 23 and maps to a graded 7-day stroke risk from 0.01% up to 28%. We get into when that granularity actually changes management in the episode.
• System-dependent disposition: Risk stratification only helps if rapid MRI or vascular imaging and neurology follow-up are available within 24 to 48 hours; otherwise, admission for expedited workup may be the safer path.