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Research paper
Correlation of non-vitamin K antagonist oral anticoagulant exposure and cerebral microbleeds in Chinese patients with atrial fibrillation
  1. Yannie Soo1,
  2. Jill Abrigo2,
  3. Kam Tat Leung1,
  4. Wenyan Liu1,
  5. Bonnie Lam1,
  6. Suk Fung Tsang1,
  7. Vincent Ip1,
  8. Karen Ma1,
  9. Bonaventure Ip1,
  10. Sze Ho Ma1,
  11. Florence Fan1,
  12. Winnie Chu2,
  13. Lawrence Wong1,
  14. Vincent Mok1,
  15. Thomas W Leung1
  1. 1 Department of Medicine and Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong
  2. 2 Department of Diagnostic Imaging and Interventional Radiology, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong
  1. Correspondence to Professor Thomas W Leung, Department of Medicine and Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, N.T, Hong Kong; drtleung{at}


Background and purpose Cerebral microbleeds (CMBs) are radiological markers which predict future intracerebral haemorrhage. Researchers are exploring how CMBs can guide anticoagulation decisions in atrial fibrillation (AF). The purpose of this study is to evaluate the correlation of non-vitamin K antagonist oral anticoagulants (NOAC) exposure and prevalence of CMBs in Chinese patients with AF.

Methods We prospectively recruited Chinese patients with AF on NOAC therapy of ≥30 days for 3T MRI brain for evaluation of CMBs and white matter hyperintensities. Patients with AF without prior exposure to oral anticoagulation were recruited as control group.

Results A total of 282 patients were recruited, including 124 patients in NOAC group and 158 patients in control group. Mean duration of NOAC exposure was 723.8±500.3 days. CMBs were observed in 103 (36.5%) patients. No significant correlation was observed between duration of NOAC exposure and quantity of CMBs. After adjusting for confounding factors (ie, age, hypertension, labile hypertension, stroke history and white matter scores), previous intracerebral haemorrhage was predictive of CMBs (OR 15.28, 95% CI 1.81 to 129.16), particularly lobar CMBs (OR 5.37, 95% CI 1.27 to 22.6). While white matter score was predictive of mixed lobar CMBs (OR 1.65, 95% CI 1.1 to 2.5), both exposure and duration of NOAC use were not predictive of presence of CMBs.

Conclusions In Chinese patients with AF, duration of NOAC exposure did not correlate with prevalence and burden of CMBs. Further studies with follow-up MRI are needed to determine if long-term NOAC therapy can lead to development of new CMBs.

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  • Contributors YS conceptualised project, wrote protocol, performed literature review, reviewed radiological images, collected and analysed data and prepared manuscript. JA and WC provided radiological support. KTL designed data extraction form, collected data and performed all statistical analyses. LW rated white matter score. SFT rated white matter score, collected and analysed data. VI, KM, VM, SHM and FF assisted patient recruitment, collected data and reviewed manuscript. LW conceptualised project, reviewed protocol and manuscript. VM interpreted data and reviewed manuscript. TWL conceptualised project, reviewed protocol and manuscript.

  • Funding This study was supported by Health and Medical Research Fund and Kwok Tak Seng Centre for Stroke Research and Intervention.

  • Competing interests None declared.

  • Ethics approval New Territories East Cluster Clinical Research Ethics Committee (NTEC CREC).

  • Provenance and peer review Not commissioned; externally peer reviewed.

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