Background and purpose Cerebral microbleeds (CMBs), which predict future intracerebral haemorrhage (ICH), may guide anticoagulant decisions for atrial fibrillation (AF). We aimed to evaluate the risk of warfarin-associated ICH in Chinese patients with AF with CMBs.
Methods In this prospective, observational, multicentre study, we recruited Chinese patients with AF who were on or intended to start anticoagulation with warfarin from six hospitals in Hong Kong. CMBs were evaluated with 3T MRI brain at baseline. Primary outcome was clinical ICH at 2-year follow-up. Secondary outcomes were ischaemic stroke, systemic embolism, mortality of all causes and modified Rankin Scale ≥3. Outcome events were compared between patients with and without CMBs.
Results A total of 290 patients were recruited; 53 patients were excluded by predefined criteria. Among the 237 patients included in the final analysis, CMBs were observed in 84 (35.4%) patients, and 11 had ≥5 CMBs. The mean follow-up period was 22.4±10.3 months. Compared with patients without CMBs, patients with CMBs had numerically higher rate of ICH (3.6% vs 0.7%, p=0.129). The rate of ICH was lower than ischaemic stroke for patients with 0 to 4 CMBs, but higher for those with ≥5 CMBs. CMB count (C-index 0.82) was more sensitive than HAS-BLED (C-index 0.55) and CHA2DS2-VASc (C-index 0.63) scores in predicting ICH.
Conclusions In Chinese patients with AF on warfarin, presence of multiple CMBs may be associated with higher rate of ICH than ischaemic stroke. Larger studies through international collaboration are needed to determine the risk:benefit ratio of oral anticoagulants in patients with AF of different ethnic origins.
- cerebral microbleeds
- intracerebral hemorrhage
- atrial fibrillation
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Collaborators Anne Chan, Howan Leung, Florence Fan, Lisa Au, Cyrus Cheng (Department of Medicine and Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong); Joshua Fok (Department of Medicine, Yan Chai Hospital); Kwok Kwong Lau (Department of Medicine, Princess Margaret Hospital); Jonas Yeung (Department of Medicine, Alice Ho Miu Ling Nethersole Hospital).
Contributors YS conceptualised the project, wrote the protocol, performed literature review, reviewed radiological images, collected and analysed data, and prepared the manuscript. JMA and WCWC provided radiological support. KTL and SFT designed the data extraction form, collected data and performed statistical analyses. HLI, SHM, KM, WCF, SHL, RL, PWN and KKW assisted in patient recruitment, collected data and reviewed the manuscript. WL and BYKL rated white matter score and reviewed the manuscript. KSLW, VM and TWL conceptualised the project, and reviewed the protocol and manuscript.
Funding The IPAAC-Warfarin study was funded by the Health and Medical Research Fund of Food and Health Bureau, and partially supported by Kwok Tak Seng Center for Stroke Research and Intervention.
Competing interests None declared.
Patient consent Obtained.
Ethics approval The study has been approved by Clinical Research Ethics Committee in New Territories East, Kowloon Central, Kowloon East, Kowloon West and Hong Kong East Clusters.
Provenance and peer review Not commissioned; externally peer reviewed.