Two-Year Outcomes of Anticoagulation for Acute Ischemic Stroke With Nonvalvular Atrial Fibrillation - SAMURAI-NVAF Study

Abstract

Background: We determined the 2-year long-term risk-benefit profile in patients with stroke or transient ischemic attack (TIA) receiving warfarin or direct oral anticoagulants (DOACs) for nonvalvular atrial fibrillation (NVAF) using a prospective, multicenter, observational registry in Japan.

Methods and results: NVAF patients within 7 days after onset of ischemic stroke/TIA were enrolled in 18 stroke centers. Outcome measures included ischemic and bleeding events and death in the 2-year follow-up period. We enrolled 1,116 patients taking either warfarin (650 patients) or DOACs (466 patients) at acute hospital discharge. DOAC users were younger and had lower National Institutes of Health Stroke Scale, CHADS₂and discharge modified Rankin Scale scores than warfarin users (P<0.0001 each). Incidences of stroke/systemic embolism (adjusted hazard ratio, 1.07; 95% CI, 0.66-1.72), all ischemic events (1.13; 0.72-1.75), and ischemic stroke/TIA (1.58; 0.95-2.62) were similar between groups. Risks of intracranial hemorrhage (0.32; 0.09-0.97) and death (0.41; 0.26-0.63) were significantly lower for DOAC users. Infection was the leading cause of death, accounting for 40% of deaths among warfarin users.

Conclusions: Stroke/TIA patients receiving DOACs for secondary prevention were younger and had lower stroke severity and risk indices than those receiving warfarin. Estimated cumulative incidences of stroke and systemic embolism within 2 years were similar between warfarin and DOACs users, but those of death and intracranial hemorrhage were significantly lower among DOAC users.

Keywords: Acute stroke; Atrial fibrillation; Direct oral anticoagulants; Intracranial hemorrhage; Warfarin.