Abstract TP528: Differences in Stroke Severity According to the Prior Medication in Patients With Non-Valvular Atrial Fibrillation

Abstract

Introduction: Atrial fibrillation is one of the most common rhythmic disorders in general population and a major risk factor of ischemic stroke. We investigated whether there was any difference in initial stroke severity and short term outcome in patients with acute ischemic stroke and known non-valvular atrial fibrillation according to their prior medication status. Methods: We retrospectively reviewed patients with acute ischemic stroke and non-valvular atrial fibrillation who admitted at six hospitals from 2013 to 2016. We selected patients with known non-valvular atrial fibrillation before admission and a CHA 2 DS 2 -VASc score of ≥2. We categorized their prior medication status as follows: 1) no antithrombotics, 2) only antiplatelet, 3) warfarin with a subtherapeutic range, 4) warfarin with a therapeutic range, 5) under-dosed novel oral anti-coagulant (NOAC), and 6) standard-dosed NOAC. We compared the initial NIHSS score and 3 month modified Rankin Scale (mRS) between the groups. Results: Total 741 patients were enrolled for analysis. Patients were categorized as follows: 177 no antithrombotics, 296 only antiplatelet, 169 warfarin with a subtherapeutic range, 36 warfarin with a therapeutic range, 25 under-dosed NOAC, and 38 standard-dosed NOAC. Median NIHSS score was lowest in patients with standard-dosed NOAC (3, interquartile range [IQR] 1-7) compared to no antithrombotics (7, IQR 2-17), only antiplatelet (4, IQR 1-12.75), warfarin with a subtherapeutic range (6, IQR 2-15), warfarin with a therapeutic range (3.5 IQR 1-7), and under-dosed NOAC (7, IQR 2-16). Proportions of the patients with good functional outcome (mRS 0-2) are as follows; 45.5% no antithrombotics, 60.4% only antiplatelet, 56.5% warfarin with subtherapeutic range, 62.1% warfarin with therapeutic range, 40.9% under-dosed NOAC, and 64.7% standard-dosed NOAC. Conclusions: Large portion of non-valvular atrial fibrillation patients do not receive proper anticoagulation, although they have higher risk of embolization. Therapeutic anticoagulation reduces the initial severity of neurologic deficit in patient with ischemic stroke.