Abstract TP174: Identifying Predictors for Final Diagnosis of Ischemic Events in an Emergency Department Observation Unit

Abstract

Introduction: Transient neurologic events have high rates of diagnostic uncertainty. Emergency department observation units (ED-OU) allow an accelerated diagnostic work up for suspected transient ischemic attacks (TIAs). However, clinical decision support regarding which patients to admit to these units is lacking. This study aimed to identify clinical features that differentiate true ischemic events from nonischemic transient neurological attacks (NI-TNA) among patients admitted to an ED-OU for suspected TIA. Methods: A retrospective analysis was performed on consecutive patients admitted to the ED-OU at a single academic center for suspected TIA. Demographics, vascular risk factors, presenting symptoms, and details of the clinical presentation were abstracted from chart review. Final discharge diagnosis was dichotomized to either ischemic event (TIA or minor stroke, TIAMS) or NI-TNA based on the treating vascular neurologist’s final diagnosis. Standard statistical tests were used for comparison testing between the two groups. Significantly different factors with p<0.2 on univariate analysis were carried forward in a multivariable logistic regression model. Results: Of 186 consecutive patients, 101 (54%) had a final diagnosis of NI-TNA and 85 (46%) of TIAMS. The median population ABCD2 score was 4 [IQR 3-4]. On univariate analysis, older age (63 vs. 70, p<0.01), history of atrial fibrillation (AF) (12% vs. 26%, p=0.01), and facial weakness (5% vs. 14% p=0.03) were associated with TIAMS. Headache (24% vs. 12%, p=0.04) and symptom duration>60min (57% vs. 40%, p=0.02) were associated with NI-TNA. On multivariable analysis, only symptom duration>60 minutes predicted NI-TNA (OR 0.39, p=0.04) and only history of AF (OR 2.53, p=0.03) predicted TIAMS. Facial weakness was strongly predictive of TIAMS (OR 3.22, p=0.05), but not significant. Conclusion: We identified two clinical features that distinguished TIAMS from NI-TNA among patients admitted to an ED-OU for suspected TIA.These may be helpful in emergency room triage of TIAMS. Data from ED-OU can be used to identify factors associated with cerebral ischemia and improve current care pathways for patients with suspected TIA, so diagnostic evaluation is received in the most appropriate setting.