Abstract 63: Three-month Outcomes in Japanese Stroke /TIA Patients With Non-valvular Atrial Fibrillation After Initiating Oral Anticoagulants: The SAMURAI-NVAF Study

Abstract

Backgound and Purpose: Recently, three non-vitamin K antagonist oral anticoagulants (NOACs) became available for patients with nonvalvular atrial fibrillation (NVAF) in Japan. We aimed to determine 3-month outcomes in ischemic stroke/TIA patients receiving NOACs or warfarin from a multicenter prospective registry (SAMURAI-NVAF registry, NCT01581502). Methods: Among 1,191 acute ischemic stroke /TIA patients enrolled between September 2011 and March 2014, we studied 916 patients (389 women, 77±10 y) who took oral anticoagulants (OACs) after index stroke and completed 3-month follow-up survey. Primary outcome measures were ischemic events, including recurrent stroke/TIA and thromboembolism, and major bleedings events, such as fatal bleeding and/or symptomatic bleeding in a critical area or organ according to the International Society on Thrombosis and Haemostasis statement. We assessed the incidence and clinical factors associated with primary outcomes within 90 days after initiating OACs. Results: NOACs were given for 370 patients (126 women, 74±9 y; dabigatran 168, rivaroxaban 183 and apixaban 19) and warfarin for 546 (263 women, 79±10 y). NOAC users had lower scores of CHADS2 (median 3 in NOAC, 4 in warfarin, p<0.001) and HAS-BLED (3, 3, p<0.001) than warfarin users. Ischemic events occurred in 14 NOAC users (3.8%; 2 women, 76±6 y, including 8 lower dose users between two approved dose for each NOAC) and 25 warfarin users (4.6%; 13 women, 81±9 y). Of these, 13 NOAC users (3.5%) and 16 warfarin users (2.9%) developed ischemic stroke/TIA. Among NOAC users, patients with ischemic events had lower body weights (53±11 vs 60±11kg, p= 0.017), more frequently had congestive heart failure (36 vs 10%, p = 0.003) and intracardiac thrombus (27 vs 4%, p < 0.001) than those without. Major bleeding events occurred in 5 NOAC users (1.4%, all using lower dose), and 14 warfarin users (2.6%). Of these, one NOAC user (0.3%) and 4 warfarin users (0.7%) developed intracranial hemorrhage. Conclusion: The 3-month incidence of ischemic events in stroke/TIA patients with NVAF was approximately 4% in both NOAC and warfarin users. Intracranial hemorrhage was relatively infrequent in NOAC users.