Abstract WP209: Efficacy And Safety Of Early Anticoagulant Therapy Initiation In Patients With Acute Ischemic Stroke Related To Atrial Fibrillation: A Systematic Review And Meta-analysis

Abstract

Background: The optimal timing for the initiation of anticoagulation in patients with acute ischemic stroke (AIS) related to atrial fibrillation (AF) remains uncertain. Observational studies assessing early anticoagulant initiation (≤14 days after index AIS) have provided conflicting results from the early use of non-vitamin K oral anticoagulants (NOACs) or vitamin K antagonists (VKAs). Methods: We performed a meta-analysis of prospective observational studies and RCTs to assess the efficacy and safety of early anticoagulation in AF-related AIS. We also compared the efficacy and safety between NOAC and VKA regimens. A random-effects model was used to pool the individual risk ratios (RRs) and corresponding 95% confidence intervals (CIs) between the two groups. Recurrent ischemic stroke was defined as the primary outcome. Results: Nine eligible studies (7 observational, 2 RCTs) were identified, including 6,840 patients with AF-related AIS (pooled mean baseline NIHSS score: 5.5; 95%CI: 3.7-7.2) who received early anticoagulation. The overall ischemic stroke recurrence rate was 5% (95%CI: 3.3-7%) and differed (p=0.05) between studies reporting anticoagulation initiation within a week (2.5%, 95%CI: 0.2-7.4%) or two weeks (6.7%, 95%CI:4.6-9.1%) from index event. The corresponding proportions of patients experiencing a fatal outcome, symptomatic or asymptomatic ICH were 4% (95%CI: 1.6-7.5%), 1.2% (95%CI: 0.3-2.6%) and 13.2% (95%CI: 6.4-22.1%), respectively. Of the 2 identified RCTs, 136 and 135 patients were randomized to early anticoagulation with NOAC or VKA, respectively. Both groups had a similar risk for ischemic stroke recurrence (RR=0.78; 95%CI: 0.32, 1.91; p=0.59). No significant differences were uncovered between early NOAC or early VKA treatment initiation for the outcomes of mortality (RR=0.57; 95%CI: 0.11, 2.97; p=0.51), symptomatic ICH (RR=0.38; 95%CI: 0.02, 9.10; p=0.55) or asymptomatic ICH (RR=1.10; 95%CI: 0.73, 1.67; p=0.64). Conclusions: Preliminary evidence from RCTs on early anticoagulation after AF-related AIS suggest that NOACs have comparable efficacy to VKAs in preventing ischemic stroke recurrence. Large scale RCTs are warranted to evaluate the potential superiority of NOACs in terms of safety endpoints.