title: Association between cerebral microbleeds on T2*-weighted MR images and recurrent hemorrhagic stroke in patients treated with warfarin following ischemic stroke.
abstract: OBJECTIVE
  Although accumulating evidence suggests the presence of microbleeds as a risk factor for intracerebral hemorrhage (ICH), little is known about its significance in anticoagulated patients. The aim of this study was to determine whether the presence of microbleeds is associated with recurrent hemorrhagic stroke in patients who had received warfarin following atrial fibrillation-associated cardioembolic infarction.
  
  
  METHODS
  A total of 87 consecutive patients with acute recurrent stroke, including 15 patients with ICH and 72 patients with cerebral infarction, were enrolled in this study. International normalized ratios (INRs), vascular risk factors, and imaging characteristics, including microbleeds on T2*-weighted MR images and white matter hyperintensity (WMH) on T2-weighted MR images, were compared in the 2 groups.
  
  
  RESULTS
  Microbleeds were noted more frequently in patients with ICH than in patients with cerebral infarction (86.7% versus 38.9%, P = .0007). The number of microbleeds was larger in patients with ICH than in patients with cerebral infarction (mean, 8.4 versus 2.1; P = .0001). INR was higher in patients with ICH than in patients with cerebral infarction (mean, 2.2 versus 1.4; P < .0001). The frequency of hypertension was higher in patients with ICH than in patients with cerebral infarction (86.7% versus 45.8%, P = .0039). Multivariate analysis revealed that the presence of cerebral microbleeds (odds ratio, 7.383; 95% confidence interval, 1.052-51.830) was associated with ICH independent of increased INR and hypertension.
  
  
  CONCLUSIONS
  The presence of cerebral microbleeds may be an independent risk factor for warfarin-related ICH, but more study is needed because of strong confounding associations with elevated INR and hypertension.
authors.affiliation: Department of Clinical Neuroscience and Therapeutics, Hiroshima University, Graduate School of Biomedical Sciences, Hiroshima, Japan. hirokiueno@hiroshima-u.ac.jp
authors.forename: H
authors.initials: H
authors.lastname: Ueno
authors.forename: H
authors.initials: H
authors.lastname: Naka
authors.forename: T
authors.initials: T
authors.lastname: Ohshita
authors.forename: K
authors.initials: K
authors.lastname: Kondo
authors.forename: E
authors.initials: E
authors.lastname: Nomura
authors.forename: T
authors.initials: T
authors.lastname: Ohtsuki
authors.forename: T
authors.initials: T
authors.lastname: Kohriyama
authors.forename: S
authors.initials: S
authors.lastname: Wakabayashi
authors.forename: M
authors.initials: M
authors.lastname: Matsumoto
mesh_terms: D000368:Aged; D000925:Anticoagulants / Q000008:administration & dosage / Q000009:adverse effects; D002545:Brain Ischemia / Q000175:diagnosis* / Q000188:drug therapy*; D002543:Cerebral Hemorrhage / Q000139:chemically induced* / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008297:Male; D012008:Recurrence; D013223:Statistics as Topic; D020521:Stroke / Q000175:diagnosis* / Q000188:drug therapy*; D016896:Treatment Outcome; D014859:Warfarin / Q000009:adverse effects* / Q000627:therapeutic use*
chemical_list: D000925:Anticoagulants; D014859:Warfarin