Management and outcomes of transient ischemic attacks in Ontario

Abstract

Background: Canadian data on the characteristics, management and outcomes of patients with transient ischemic attack (TIA) are lacking. We studied prospectively a cohort of consecutive patients presenting with TIA to the emergency department of 4 regional stroke centres in Ontario.

Methods: Using data from the Ontario Stroke Registry linked with provincial administrative databases, we determined the short-term outcomes after TIA and assessed patient management in the emergency department and within 30 days after the index TIA. We compared the TIA patients with a cohort of patients who had ischemic stroke.

Results: Three-quarters of the TIA patients were discharged from the emergency department. After discharge, the 30-day stroke risk was 5% (13/265) overall and 8% (13/167) among those with a first-ever TIA; the 30-day risk of stroke or death was 9% (11/127) among the TIA patients with a speech deficit and 12% (9/76) among those with a motor deficit. Half of the cases of stroke occurred within the first 2 days after the TIA. Diagnostic investigations were underused in hospital and on an outpatient basis within 30 days after the index TIA, the rates being as follows: CT scanning, 58% (211/364); carotid Doppler ultrasonography, 44% (162/364); echocardiography, 19% (70/364); cerebral angiography, 5% (19/364); and MRI, 3% (11/364). Antithrombotic therapy was not prescribed for more than one-third of the patients at discharge. Carotid endarterectomy was performed in 2% within 90 days.

Interpretation: Patients in whom TIA is diagnosed in the emergency department have high immediate and short-term risks of stroke. However, their condition is underinvestigated and undertreated compared with stroke: many do not receive the minimum recommended diagnostic tests within 30 days. We need greater efforts to improve the timely delivery of care for TIA patients, along with investigation of treatments administered early after TIA to prevent stroke.

Fig. 1: Proportions of patients who underwent diagnostic investigations (inpatient or outpatient) within 30 days after presenting to an emergency department with transient ischemic attack (TIA) (n = 364) or ischemic stroke (n = 410). The proportions of the TIA group were all much lower (p < 0.001) than those of the stroke group except for carotid Doppler ultrasonography (p = 0.08). Echo = echocardiography, Angio = angiography.

Fig. 2: Early risk of stroke after discharge from the emergency department among patients with a first-ever TIA (n = 167). Note that half of the cases of stroke occurring within 3 months happened in the first 2 days after TIA.