Abstract TP289: Diagnostic Evaluation of Patients Admitted to Emergency Department Observation Unit for Suspected TIA

Abstract

Introduction: Emergency department observation units (ED-OU) allow patients with a suspected transient ischemic attack (TIA) an expedited workup without the need for a prolonged inpatient admission. Despite risk stratification scores and physician evaluation, however, the reliability in diagnosis of TIA remains poor, which may lead to unnecessary testing. This study aimed to identify and compare the diagnostic workup between patients with final diagnosis of true vascular events (TIA or minor stroke, TIAMS) versus nonischemic transient neurological attacks (NI-TNA) in suspected TIA patients admitted to an ED observation unit. Methods: A retrospective analysis was performed on consecutive patients who were admitted to an ED-OU at a single center for suspected TIA. All diagnostic testing obtained during observation stay was abstracted from chart review. Final discharge diagnosis was dichotomized to either TIAMS or NI-TNA. Standard statistical tests were used for comparison testing between the two groups with significance defined as p<0.05. Results: Of 186 suspected TIA patients admitted to an ED-OU, median ABCD2 score was 4 [IQR 3-4]. Final diagnosis was TIAMS in 85 (46%) patients and NI-TNA in 101 (54%) patients. A total of 182 (98%) patients had non-contrast head CT (NCHCT); 160 (86%) brain MRI; 117 (63%) extracranial vessel imaging; 116 (62%) transthoracic echocardiogram (TTE); and 108 (58%) intracranial vessel imaging. Assessing diagnostic work-up by final diagnosis, TTE (78% vs 40%, p<0.01), and extracranial imaging (75% vs 55%, p<0.01) were more common in patients with TIAMS. Restricted diffusion on MRI (27% vs. 2%, p<0.01) and abnormality on TTE (50% vs. 28% p=0.02) were more common in TIAMS patients. The overall rate of symptomatic stenosis was low: 1 patient had a symptomatic carotid and 4 patients had symptomatic intracranial stenosis. Conclusion: Extensive diagnostic testing is done on patients with suspected TIA admitted to ED-OU, with more studies acquired on patients with true ischemic events as compared to NI-TNA. As the use of ED-OUs increases, refinement of current diagnostic testing algorithms to reduce workup for cerebrovascular disease among patients with NI-TIA and among different ischemic stroke subtypes is warranted.