The Canadian TIA Score Is Now Prospectively Validated

Anthony S. Kim, MD reviewing Perry JJ et al. BMJ 2021 Feb 4

The elevated risk for stroke after a transient ischemic attack (TIA) presents an important opportunity for interventions to prevent an impending stroke. Simple risk stratification scores, such as the ABCD² score, which includes just five elements (Age, Blood pressure, Clinical features, Duration of symptoms, and Diabetes) are validated for clinical use and for clinical research. But with simplicity also comes certain limitations on predictive power. The Canadian TIA Score was previously derived to stratify the short-term stroke risk after TIA. This score is composed of points for 13 clinical variables that are summed to produce a total score between –3 and +23. The variables include symptoms ≥10 minutes (+2 points), history of vertigo (–3 points), triage diastolic blood pressure ≥110 mm Hg (+3 points), atrial fibrillation (+2 points), and platelet count ≥400 x 10⁹/liter (+2 points), and new or old infarct on noncontrast CT (+1 point). MRI data are not included.

Now investigators have prospectively validated the Canadian TIA Score in 7607 adults diagnosed with TIA or minor stroke at 13 emergency departments from 2012 to 2017. Within 7 days after the qualifying event, 108 patients (1.4%) had a stroke and 83 (1.1%) had a carotid artery revascularization procedure. The score categorized 16% of patients as having low risk (<1% risk), 72% medium risk (2.3% risk), and 12% high risk (>5% risk) and had better overall performance than the ABCD² score, particularly for identifying low-risk patients.