Ninety‐Day Stroke or Transient Ischemic Attack Recurrence in Patients Prescribed Anticoagulation in the Emergency Department With Atrial Fibrillation and a New Transient Ischemic Attack or Minor Stroke

Background For patients with atrial fibrillation seen in the emergency department (ED) following a transient ischemic attack (TIA) or minor stroke, the impact of initiating oral anticoagulation immediately rather than deferring the decision to outpatient follow‐up is unknown. Methods and Results We conducted a planned secondary data analysis of a prospective cohort of 11 507 adults in 13 Canadian EDs between 2006 and 2018. Patients were eligible if they were aged 18 years or older, with a final diagnosis of TIA or minor stroke with previously documented or newly diagnosed atrial fibrillation. The primary outcome was subsequent stroke, recurrent TIA, or all‐cause mortality within 90 days of the index TIA diagnosis. Secondary outcomes included stroke, recurrent TIA, or death and rates of major bleeding. Of 11 507 subjects with TIA/minor stroke, atrial fibrillation was identified in 11.2% (1286, mean age, 77.3 [SD 11.1] years, 52.4% male). Over half (699; 54.4%) were already taking anticoagulation, 89 (6.9%) were newly prescribed anticoagulation in the ED. By 90 days, 4.0% of the atrial fibrillation cohort had experienced a subsequent stroke, 6.5% subsequent TIA, and 2.6% died. Results of a multivariable logistic regression indicate no association between prescribed anticoagulation in the ED and these 90‐day outcomes (composite odds ratio, 1.37 [95% CI, 0.74–2.52]). Major bleeding was found in 5 patients, none of whom were in the ED‐initiated anticoagulation group. Conclusions Initiating oral anticoagulation in the ED following new TIA was not associated with lower recurrence rates of neurovascular events or all‐cause mortality in patients with atrial fibrillation.