Background Cerebral microbleeds (CMBs) are a biomarker for anticoagulant-related intracerebral haemorrhage (ICH) in patients with atrial fibrillation (AF). Little was known about the risk of new CMB development and ICH in patients on Direct Oral Anticoagulants (DOAC). The study aimed to investigate the risk of new CMBs development and the associated risk of ICH among patients with AF on DOAC.
Methods Patients with AF on DOACs were prospectively recruited to undergo MRI at baseline and at 2 years. Primary outcome was new CMBs development. Secondary outcomes were ICH, ischaemic stroke, and systemic embolism.
Results Of the 261 patients included in the final analysis. New CMBs were detected in 57 patients. Baseline CMBs was associated with an increased risk of developing new CMBs on follow-up (aHR 4.50, 95% CI 1.74-11.67). There were no differences in secondary outcomes between patients with and without new CMBs development. The absolute rate of ischaemic stroke was consistently higher than ICH in patients with and without new CMB development. There were no signals suggesting interactions between any specific DOAC, duration of DOAC therapy and the presence of baseline CMBs for developing new CMBs.
Conclusion In patients with AF on DOAC, baseline CMBs increased the risk of new CMBs development. The preliminary data does not suggest a large increase in the risk of ICH in patients with CMB progression in the short term. Further studies with larger sample sizes are needed to determine the long-term risk of stroke associated with CMB progression.