Abstract TMP112: Left Atrial Enlargement is Associated With Anticoagulation Failure in Patients With Acute Ischemic Stroke and Atrial Fibrillation

Abstract

Background: Biomarkers to predict anticoagulation failure in patients with atrial fibrillation (AF) may help identify high-risk AF patients for further study. We hypothesize that left atrial enlargement (LAE) is more prevalent in AF patients admitted with ischemic stroke who are therapeutic, as opposed to non-therapeutic (NT), on anticoagulation. Methods: We included consecutive patients with AF admitted with a diagnosis of ischemic stroke between April 1 st , 2015 and December 31 st , 2016. Patients were divided into two groups based on whether they were therapeutic (warfarin with international normalized ratio ≥ 2.0 or non-vitamin K oral anticoagulant with uninterrupted use in the prior 2 weeks) vs. non-therapeutic on anticoagulation. We compared clinical and imaging characteristics, cardiac data (left atrial diameter on transthoracic echocardiogram), and outcomes (discharge modified Rankin Scale, discharge disposition, and symptomatic intracranial hemorrhage [sICH]) between the two groups. Multivariable logistic regression was used to estimate associations between therapeutic anticoagulation and variables, including CHADS 2 score and LAE (none/mild vs. moderate/severe). Results: We identified 225 patients; 52 (23.1%) were therapeutic on anticoagulation. The baseline demographics and risk factors were similar between the two groups. Patients therapeutic on anticoagulation were more likely to have a larger left atrial diameter (45.6 ± 9.2 vs. 42.3 ± 8.6 mm, p = 0.032), a higher CHADS2 score (2.9 ± 1.1 vs. 2.4 ± 1.1, p = 0.03), and sICH (13.5% vs. 3.5%, p = 0.013). After adjusting for the CHADS 2 score, patients who had stroke despite therapeutic anticoagulation were more likely to have moderate to severe LAE (odds ratio 2.05, 95% confidence interval 1.01-4.16). Results were unchanged when the CHA 2 DS 2 -VASc score was used. Conclusion: LAE is associated with anticoagulation failure in AF patients admitted with an ischemic stroke. This provides indirect evidence that LAE may portend failure of anticoagulation therapy in patients with AF; further studies are needed to delineate the significance of this association and improve stroke prevention strategies.