Insufficient Warfarin Therapy Is Associated With Higher Severity of Stroke Than No Anticoagulation in Patients With Atrial Fibrillation and Acute Anterior-Circulation Stroke

Background: Insufficient anticoagulant intensity on admission is common in stroke patients with atrial fibrillation (AF) on vitamin K antagonist (VKA) therapy. Nevertheless, the effects of VKA under-treatment on stroke severity or arterial occlusion are not well known. The aim of the present study was to investigate the relationship between insufficient VKA therapy and stroke severity, or the site of arterial occlusion in patients with acute ischemic stroke (AIS) and AF. Methods and Results: From March 2011 through July 2016, 446 consecutive patients with AF and AIS were recruited. Of the 446 patients, 364 (167 women; median age, 79 years; IQR, 71-86 years) with anterior-circulation stroke were assessed to investigate the effects of insufficient VKA. Of these, 281 were on no anticoagulant, 53 were undertreated with a VKA, and 30 were sufficiently treated with VKA on admission (PT-INR >= 2.0 for patients <70 years and PT-INR >= 1.6 for >= 70 years old). On multivariate analysis, insufficient VKA was independently associated with severe stroke (i.e., initial NIHSS score >= 10; OR, 2.70, P=0.022) and higher prevalence of proximal artery occlusion (OR, 1.91; P=0.039) compared with no anticoagulant therapy. Conclusions: Insufficient VKA therapy on admission was associated with higher severity of stroke and higher prevalence of proximal artery occlusion in patients with AF and acute anterior-circulation stroke compared with no anticoagulant medication.