Abstract 132: The Canadian TIA Rule - A Decision Rule to Predict the Risk Of Stroke Within Seven Days In The Emergency Department
Background: Stroke prevention after TIA is dependent on rapid intervention in those at highest risk. Previous risk scores have not been prospectively developed and thus do not consider all relevant variables. The goal of this study was to derive a clinical score for TIA patients to identify those at high risk for stroke ≤ 7 days.
Methods: We conducted a prospective cohort study in 8 academic Canadian EDs. We enrolled consecutive adult ED patients diagnosed with a TIA. Standardized clinical variables were recorded by physicians on data forms prior to discharge/admission. Our primary outcome was stroke ≤ 7 days of TIA diagnosis. We derived a clinical score using logistic regression analysis.
Results: We prospectively enrolled 3,903 patients including 85 patients with a subsequent stroke ≤ 7 days. From this cohort we derived the Canadian TIA Score. The Canadian TIA Score identifies patients at minimal risk of subsequent stroke ≤ 7 days (probability < 0.5%), low risk (0.5-2.5%), high risk (2.6-10.0%), and critical risk (>10.0%). This score contains 13 variables; 9 clincal: 1) initial TIA (in lifetime) 2) symptoms lasting ≥10 minutes, 3) already on an antiplatelet agent, 4) history of carotid stensosis, 5) history of gait disturbance, 6) unilateral weakness, 7) vertigo, 8) initial diastolic blood pressure ≥110 mmHg, 9) history or exam finding of dysarthria or aphasia; and four from investigations: 1) atrial fibrillation on electrocardiogram, 2) infarction on CT head, 3) platelets ≥400 x 109/L, 4) glucose ≥15 mmol/L. Variables were assigned point values ranging from 4 to -3, and added, obtaining a score from -3 to 19. This model has good discrimination with a c-statistic of 0.77 (95%CI: 0.73-0.82).
Importance: The Canadian TIA Score identifies the subsequent stroke risk at 7 days following a TIA. Following validation, the Canadian TIA Score will allow physicians to selectively expedite investigations/specialist assessment and allow for safe less urgent follow-up of patients at low risk. Appropriate intervention is contingent on appropriate risk assessment.
- © 2012 by American Heart Association, Inc.