Japan has the highest number of magnetic resonance imaging units in the world, and citizens can freely choose medical care at any hospital or clinic. The authors aimed to investigate the triage of patients with suspected transient ischemic attack (TIA) or minor stroke in this unique Japanese healthcare system. In this cohort study, patients with suspected TIA or minor stroke (National Institutes of Health Stroke Scale score <4) within 7 days after onset were prospectively enrolled and followed for 1 year. The high-risk group was defined as having at least one of the following 5 items at the initial visit: (1) atrial fibrillation, (2) carotid stenosis, (3) crescendo TIA, (4) definite focal brain symptoms, or (5) ABCD2 score of 4 or higher. After the initial assessment, the patients were diagnosed as having acute ischemic cerebrovascular syndrome (AICS) or stroke mimic. AICS was classified into 3 categories including definite, probable, and possible AICS, based on evidence of neurological deficits and brain infarction on the imaging study. A total of 353 patients were enrolled and 89.8% of the patients were examined by diffusion-weighted imaging at the initial visit. Kaplan-Meier analyses demonstrated a statistically significant difference in subsequent stroke risk when the patients were triaged by the ABCD2 score (P = .031), 5-item high-risk categorization (P = .032), or AICS classification (P = .001).
This study demonstrates that hospitals and clinics with imaging facilities play a major role in triage and that the ABCD2 score, 5-item high-risk categorization, and AICS classification are useful as triage tools for patients with suspected TIA or minor stroke.