ED-Prescribed Anticoagulation Post-TIA and Recurrence, Mortality in Atrial Fibrillation

Among patients with established atrial fibrillation (AF), following a transient ischemic attack (TIA), initiation of anticoagulation therapy in the emergency department (ED) does not reduce recurrence of neurovascular events or all-cause mortality. These findings were published in the Journal of the American Heart Association.

Patients with TIA are at elevated risk for future stroke, as are patients with AF. This study was designed to evaluate whether anticoagulation therapy may mitigate some of the risk for recurrence of neurovascular events among patients with AF and TIA.

This study was a planned secondary analysis of patients (N=1286) with AF who presented with TIA to 1 of 13 EDs in Canada between 2006 and 2018. The primary outcome was a composite of ischemic or hemorrhagic stroke, TIA recurrence, or mortality at 90 days.

The patients had a mean age of 77.3 (SD, 11.1) years, 52.4% were men, 73.5% had hypertension, 44.2% had history of stroke or TIA, 54.4% (n=699) were already on anticoagulation therapy, and 6.9% (n=89) started anticoagulation therapy at the ED.

At 90 days, the cumulative incidence of subsequent TIA was 6.5%, subsequent ischemic stroke was 4.0%, mortality was 2.6%, and intracerebral hemorrhage was 0.4%.

Stratified by anticoagulant usage, the patients who received anticoagulation therapy at the ED had higher rates of stroke at 90 days (10.1%) than those who were already taking anticoagulants (3.3%) or were not taking anticoagulants (4.0%). Similar trends were observed for TIA recurrence (7.9% vs 6.7% vs 5.8%, respectively) and mortality (16.9% vs 10.2% vs 12.8%, respectively).

Increased risk for the composite outcome at 90 days was associated with medium Canadian TIA Score compared with a low score (odds ratio [OR], 3.18; 95% CI, 1.47-6.85).

The final model predicting the composite outcome at 90 days (area under the curve [AUC], 0.64; 95% CI, 0.59-0.68; P =.004) found that anticoagulation therapy prescribed in the ED tended to increase risk (OR, 1.37; 95% CI, 0.74-2.52) whereas already taking anticoagulation therapy tended to decrease risk (OR, 0.74; 95% CI, 0.44-1.24).

A major limitation of this study is the small sample size of patients who received anticoagulation therapy at the ED.

These data did not find that ED-prescribed anticoagulation therapy post-TIA decreases risk for recurrence or mortality at 90 days among patients with AF. The study authors wrote, “The role and timing of ED-prescribed anticoagulation in patients with atrial fibrillation and a new TIA who are not already on anticoagulation need further investigation.”

Disclosure: One of the study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.