Abstract 133: Magnetic Resonance Imaging Based Transient Ischemic Attack Triage In The Emergency Department Is Feasible And Safe

Abstract

Objective: To evaluate the safety and feasibility of a magnetic resonance imaging (MRI) based transient ischemic attack (TIA) triage pathway in the emergency department (ED). We hypothesized that an MRI based triage pathway in an academic setting would be feasible and associated with a low rate of stroke recurrence. Methods: From January 2010 to May 2011, consecutive patients assessed in our institution’s ED for suspicion of TIA were evaluated by a neurologist and underwent MRI with diffusion weighted imaging (DWI) and MRA of the head and neck within 12 hours per radiology department convention. By protocol, the neurologist recommended admission for patients with restricted diffusion on MRI, symptomatic vessel stenosis, or per clinical judgment. Final diagnosis was adjudicated by the treating neurologist at the time of discharge as definite or possible transient cerebrovascular event, or a non-cerebrovascular event. Stroke recurrence was evaluated at 1 week, 3 months, and 1 year with a telephone interview. Results: One hundred and twenty nine patients were enrolled with a mean age of 69 years (+/-16.8) and median ABCD 2 of 3 (IQR 3-4). Final diagnosis was definite transient cerebrovascular event in 77 (59.7%), possible in 21 (16.3%), and other in 31 (24%). At the time of triage, 112 (92%) patients underwent brain MRI in the ED after a median delay of 8.2 hours (IQR 4.8-14.7) from arrival and 15.7 hours (IQR 9.9-22.8) from symptom onset. No patients experienced a recurrent stroke before imaging. Twenty two (19.6%) patients had a positive DWI and 9 (8%) had a symptomatic vessel stenosis. All but two patients with a positive DWI or MRA were admitted. In total, 46 of the 129 (35.7%) patients were hospitalized and one (2.2%) had a recurrent stroke after 90 days. Of 83 patients discharged from the ED, one (1.2%) had a minor stroke at one week. This patient’s baseline MRI was DWI negative and MRA was without stenosis. Altogether, among 98 patients with a final diagnosis of possible or definite transient cerebrovascular event, the rate of recurrent stroke was 1.03% at 7 and 90 days, and 2.2% at one year. Conclusion: Acute evaluation of TIA using an MRI based triage approach is feasible and associated with a low rate of recurrent stroke.