Is Transient Ischemic Attack a Medical Emergency? An Evidence-Based Analysis

Abstract

Background: Transient ischemic attack (TIA) is a brief episode of dysfunction in a confined area of the brain. The risk of stroke following TIA is approximately 4% within the first 2 days and 9% within the first month. Therefore, early diagnosis and treatment is critical to reduce mortality and risk of stroke in patients who have experienced a TIA.

Objectives: This systematic review aimed to investigate the impact of the urgent evaluation and initiation of treatment of patients with TIA on the risk of subsequent stroke and death.

Data sources: A literature search was performed for studies published from January 1, 2007, until December 21, 2012. The search was updated monthly to April 1, 2013.

Results: All identified studies showed that urgent assessment and initiation of treatment of TIA is an effective strategy in reducing the incidence of stroke. Among these, a large observational study found a large effect in that the risk of stroke was reduced by 80%, and a Canadian study found that providing urgent care significantly reduced the rate of stroke in high-risk patients. Another Canadian study reported a significant reduction in the rate of death among patients referred to stroke prevention clinics, compared to patients not referred to such services. One study showed that patients discharged from an emergency department with standard care had significantly higher rates of stroke and subsequent TIA in the first month, compared to those who were hospitalized. However, another study showed that for patients at low to moderate risk, rate of stroke was similar between inpatients and those managed in a TIA clinic.

Limitations: Our analysis was restricted to the effect of the combined interventions. The magnitude of benefit of each individual component of the intervention cannot be determined through this review.

Conclusions: The results of this systematic review have important clinical and health system implications. Urgent management of TIA patients in specialized TIA clinics rather than regular practice results in a lower rate of stroke and disability.

Figure 1:. ABCD² Scale for Risk of Stroke Following Transient Ischemic Attack

Figure 2:. Cumulative Risk of Subsequent Vascular Events: Transient Ischemic Attach Versus Minor Ischemic Stroke

Figure 3:. Citation Flow Chart

Figure 4:. One-Year Mortality After Transient Ischemic Attack or Ischemic Stroke: Patients Referred Versus not Referred to Stroke Prevention Clinics

Figure 5:. Rate of Stroke in 90 Days Following Transient Ischemic Attack: TIA Clinic Versus Regular Clinical Practice or Predicted Risk

Figure 6:. Rate of Stroke at 6 Months and 90 Days Following Transient Ischemic Attack in the EXPRESS Study

Figure 7:. Rate of Stroke Following Transient Ischemic Attack at 90 Days in Ontario Study According to Risk Category

Figure 8:. Rate of Stroke Following Transient Ischemic Attack at 90 Days and 1 Year in the SOS-TIA Study

Figure 9:. Rate of Stroke Following Transient Ischemic Attack, by Risk Scores and Criteria for Emergency Treatment

Figure 10:. Rate of Stroke and Other Major Events at 90 Days, Inpatient Versus Emergency Department Observation Unit

Figure 11:. Rate of Stroke and Transient Ischemic Attack Following Admission to Hospital or Discharge from Emergency Department

Figure 12:. Rate of Stroke or Transient Ischemic Attack at 4 Weeks, by Risk Scores

Figure 13:. Rate of Stroke and Transient Ischemic Attack in Patients Managed in TIA Clinic or Admitted to Hospital

Figure 14:. Risk of Stroke in Patients Admitted to Stroke Unit, by Brain Status and Risk Scores