Left Atrial Enlargement and Anticoagulation Status in Patients with Acute Ischemic Stroke and Atrial Fibrillation

Abstract

Despite anticoagulation therapy, ischemic stroke risk in atrial fibrillation (AF) remains substantial. We hypothesize that left atrial enlargement (LAE) is more prevalent in AF patients admitted with ischemic stroke who are therapeutic, as opposed to nontherapeutic, on anticoagulation. We included consecutive patients with AF admitted with ischemic stroke between April 1, 2015, and December 31, 2016. Patients were divided into two groups based on whether they were therapeutic (warfarin with an international normalized ratio ≥ 2.0 or non-vitamin K oral anticoagulant with uninterrupted use in the prior 2 weeks) versus nontherapeutic on anticoagulation. Univariable and multivariable models were used to estimate associations between therapeutic anticoagulation and clinical factors, including CHADS2 score and LAE (none/mild versus moderate/severe). We identified 225 patients during the study period; 52 (23.1%) were therapeutic on anticoagulation. Patients therapeutic on anticoagulation were more likely to have a larger left atrial diameter in millimeters (45.6 ± 9.2 versus 42.3 ± 8.6, P = .032) and a higher CHADS2 score (2.9 ± 1.1 versus 2.4 ± 1.1, P = .03). After adjusting for the CHADS2 score, patients who had a stroke despite therapeutic anticoagulation were more likely to have moderate to severe LAE (odds ratio, 2.05; 95% confidence interval, 1.01-4.16). 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.