Non-Vitamin K Antagonist Oral Anticoagulants Do Not Increase Cerebral Microbleeds

Background: Atrial fibrillation (AF) is a cardiac arrhythmia that frequently induces ischemic strokes. Nowadays, non-vitamin K antagonist oral anticoagulants (NOACs) have come into widespread use for cardiogenic embolism prevention in place of warfarin. Recently, cerebral microbleeds (CMBs) have been noticed for their potential implication in cerebral small vessel disease. We hypothesized that NOACs do not have an unfavorable influence over cerebral small vessels and investigated whether NOACs increase CMBs in AF patients in a prospective manner. Methods: We performed baseline magnetic resonance imaging (MRI) examinations on the 69 enrolled AF patients and re-examined second round of MRI 1 year later. The enrolled patients continued the same anticoagulation therapy during the meantime. Results: CMBs did not develop in the 23 patients with NOACs for 1 year. Nine patients with antiplatelets also did not develop CMBs. On the other hand, 3 of 21 patients continued on warfarin and 3 of 9 with warfarin and antiplatelets had CMBs. When divided into 2 groups according to whether the CMBs developed, significant differences in the incidence of using NOACs were observed between the 2 groups (P = .02). A multivariate regression analysis showed that warfarin was independently related to the new development of CMBs (hazard ratio, 10.75; 95% confidence interval, 1.22-94.99; P = .03). Conclusions: This is the first report to clarify that NOACs do not increase CMBs in AF patients longitudinally in 1 year. Further consideration will be continued with a much longer follow-up in large samples.