To compare the diagnostic workup between patients with final diagnosis of true ischemic event versus nonischemic transient neurological attacks (NI-TNA) in suspected TIA patients admitted to an ED observation unit (ED-OU).

ED-OUs allow patients with suspected TIA an expedited workup without a prolonged inpatient admission. Despite risk stratification scores and physician evaluation, the reliability in diagnosis of TIA remains poor, which may lead to unnecessary testing.

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 TIA or minor stroke (TIAMS) or NI-TNA. Standard statistical tests were used for comparison testing.

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 workup by final diagnosis, TTE (78% vs 40%, p<0.01), and extracranial imaging (75% vs 55%, p<0.01) were more common in TIAMS patients. 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. 

More extensive testing is acquired on patients with true ischemic events as compared to NI-TNA patients admitted to ED-OU for suspected TIA. As the use of ED-OUs increases, refinement of current diagnostic algorithms to reduce workup for cerebrovascular disease among patients with NI-TIA and among different ischemic stroke subtypes is warranted.