Effects of sufficient anticoagulation on ischemic stroke outcomes in patients with nonvalvular atrial fibrillation

Abstract

Background: Optimal anticoagulation therapy reduces the risk of ischemic stroke in patients with nonvalvular atrial fibrillation (AF). Therefore, we aimed to evaluate the effects of prior anticoagulation therapy with vitamin K antagonists (VKAs) and direct oral anticoagulants (DOACs) on ischemic stroke outcomes in patients with nonvalvular AF.Methods: We enrolled 487 patients with ischemic stroke and nonvalvular AF between January 2013 and August 2020. The infarct volume was semi-automatically evaluated using diffusion-weighted magnetic resonance imaging. Patients were categorized into no anticoagulation, undertreated anticoagulation, and sufficient anticoagulation (with VKA or DOAC) groups based on their pre-admission anticoagulant use, and the clinical characteristics were compared between the groups.Results: Among the included patients, 374 (76.8%), 50 (10.3%), 10 (2.1%), and 53 (10.9%) patients received no anticoagulants, were undertreated with a VKA, were sufficiently treated with a VKA, and received DOACs, respectively, before stroke. Multivariate analysis revealed that optimal anticoagulation was independently associated with a low risk of severe stroke (odds ratio, 0.553; 95% confidence interval, 0.308–0.992; P=0.047). Additionally, the DOAC group had a significantly smaller mean infarct volume than the other groups (45.8±73.2, 45.0±69.1, 30.9±24.7, and 12.6±24.9 mL in the no anticoagulation, insufficient VKA, sufficient VKA, and DOAC groups, respectively; P=0.011).Conclusion: Sufficient pre-stroke anticoagulation is associated with mild stroke severity and good outcomes at 3 months post-stroke. Additionally, pre-stroke DOAC treatment is associated with smaller infarct volume in patients with ischemic stroke and nonvalvular AF.