Cerebral microbleeds and risk of adverse outcomes in patients with atrial fibrillation: a systematic review and meta-analysis

Abstract

Abstract Background Long-term anticoagulation in patients with atrial fibrillation (AF) imposes a careful balance between the thromboembolic and hemorrhagic risks. An association between cerebral microbleeds (CMBs) and an increased risk of intracranial hemorrhage (ICH) has already been described; however, conflicting evidence exist on the association with ischemic stroke (IS). Although CMBs are often observed in AF patients, the actual prevalence and the magnitude of the risk of adverse events in patients with CMBs is unclear. Purpose We aimed to estimate the pooled prevalence of CMBs in patients with AF through a systematic review and meta-analysis of the literature. Additionally, we evaluated the risk of ICH and IS according to the presence and burden of CMBs. Methods We perform a systematic search on PubMed and EMBASE from inception to 6th March 2021. We included all studies reporting the prevalence of CMBs, the incidence of ICH and/or IS in AF by presence of CMBs. Pooled prevalence and odds ratios (OR), along with their 95% Confidence Intervals (CI), were computed using random-effect models; we also calculated 95% Prediction Intervals (PI) for each outcome investigated. Additionally, we performed subgroup analyses according to the number and localization of CMBs. Results We retrieved 562 records from the literature search, and 17 studies were finally included. Pooled prevalence of CMBs in AF population was 28.3% (95% CI: 23.8%-33.4%; 95% PI: 12.2%-52.9%, Figure 1). Individuals with CMBs showed a higher risk of both ICH (OR: 3.04, 95% CI: 1.83–5.06) and IS (OR: 1.78, 95% CI: 1.26–2.49). Moreover, patients with more than 5 CMBs, as well as patients with both lobar and mixed CMBs, showed a higher risk of ICH. Conclusions CMBs were found in 28.3% of AF patients, with 95% PIs indicating a potentially higher prevalence. Moreover, CMBs were associated with an increased risk of both ICH and IS, with the effect potentially modulated by their number and localization. CMBs may represent an important and often overlooked risk factor for adverse outcomes in patients with AF. Funding Acknowledgement Type of funding sources: None. Prevalence of CMBs in patients with AF