Abstract 41: Cerebral Microbleeds and the Effect of Anticoagulation on Outcomes in 3699 Patients With Embolic Strokes of Undetermined Source: An Exploratory Analysis of the NAVIGATE ESUS Trial

Background: Cerebral microbleeds (CMBs) are reported to predict recurrent stroke and antithrombotic-related intracerebral hemorrhage (ICH). We characterize CMBs in a well-defined population of embolic strokes of undetermined source (ESUS). Notably, we report for the first time interactions between CMBs and effects of random assignment to anticoagulant therapy. Methods: Subgroup analyses of the NAVIGATE ESUS randomized trial comparing rivaroxaban 15 mg vs. aspirin 100 mg daily were performed. CMBs were rated on T2*-GRE sequences obtained at baseline MRI in 3699 participants (mean age 67y). Multivariable regression analyses were used to identify variables independently associated with CMBs. Cox proportional hazards models were used to estimate the contribution of CMBs to risk of recurrent stroke, ischemic stroke, ICH and all-cause mortality. Analyses followed the intent-to-treat paradigm. Results: CMBs were present in 11% of participants. CMBs were strictly deep in 55%, lobar in 26%, and mixed in 19% of cas...