The clinical relevance of cerebral microbleeds in patients with cerebral ischemia and atrial fibrillation.

The clinical significance of cerebral microbleeds (CMB) in patients hospitalized with atrial fibrillation (AF) and cerebral ischemia is unclear. We aimed to determine the prevalence of CMB in this population and determine the future risk of intracerebral hemorrhage (ICH) and cerebral infarction (CI). The medical records and brain imaging of patients hospitalized with cerebral ischemia due to AF between 2008 and 2011 were reviewed. Followup was obtained through medical record review, mailed survey, and acquisition of death certificates. Prevalence was calculated from those patients with a hemosiderin-sensitive MRI sequence. Recurrent CI and ICH were calculated using Kaplan-Meier curves censored at 3 years. Among 426 patients hospitalized with cerebral ischemia due to AF, 134 had an MRI with hemosiderin-sensitive sequences. The prevalence of CMB was 27.6%. At 3 years, 90.6% of CMB-negative patients were overall stroke free (ICH and CI) compared to 78.6% CMB-positive patients (p = 0.0591). Only one patient in the CMB-positive group had an ICH distant to the CMB. There was a nonsignificant trend toward higher recurrent CI, recurrent overall stroke rate, and mortality in patients with 5 or more CMB compared to 0-4 CMB. The rate of prospective CI in patients with prior cerebral ischemia due to AF is higher than the rate of ICH in patients with CMB. Further study is warranted to assess larger numbers of patients to determine appropriate antithrombotic use in this high-risk population.