title: Cerebral microbleeds in nonlacunar brain infarction are associated with lower coated-platelet levels.
abstract: BACKGROUND
  Coated-platelets are a subset of platelets with high procoagulant potential observed on dual-agonist stimulation with collagen and thrombin. Coated-platelet levels are elevated in patients with nonlacunar ischemic stroke compared with controls, although the presence of early hemorrhagic transformation is associated with lower coated-platelet levels. In contrast to infarction, patients with spontaneous intracerebral hemorrhage have lower coated-platelet levels, and these levels inversely correlate with bleed size. Cerebral microbleeds (CMBs) represent previous small hemorrhagic occurrences. We undertook a pilot study to investigate coated-platelet production and the presence of CMBs in patients with nonlacunar ischemic stroke.
  
  
  METHODS
  Coated-platelet levels were determined in 110 consecutive patients with a diagnosis of nonlacunar stroke. Microbleeds were identified using the published criteria by an experienced stroke neurologist. Coated-platelet levels were compared statistically between patients with and without CMBs using the nonparametric Wilcoxon rank sum test.
  
  
  RESULTS
  Coated-platelet levels (median [interquartile range]) for all patients were 44.1% [34%-51.2%]. CMBs were detected in 22 patients (20%); these patients had significantly lower coated-platelet levels compared with those without CMBs (35.6% [22.6%-47.2%] versus 45.1% [36.1%-51.5%]; P = .025), whereas other demographic and clinical factors did not differ significantly.
  
  
  CONCLUSIONS
  The presence of CMBs in patients with nonlacunar ischemic stroke is associated with lower levels of coated-platelets. Larger prospective studies are needed to better establish the potential connection between altered coated-platelet synthesis, microbleeds, cerebral infarction, and possible hemorrhage-prone vascular changes.
authors.affiliation: Department of Neurology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma; Department of Veterans Affairs Medical Center, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma. Electronic address: calin-prodan@ouhsc.edu.
authors.forename: Calin I
authors.initials: CI
authors.lastname: Prodan
authors.affiliation: Department of Biostatistics and Epidemiology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma.
authors.forename: Julie A
authors.initials: JA
authors.lastname: Stoner
authors.affiliation: Department of Neurology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma.
authors.forename: David L
authors.initials: DL
authors.lastname: Gordon
authors.affiliation: Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma.
authors.forename: George L
authors.initials: GL
authors.lastname: Dale
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001777:Blood Coagulation; D001792:Blood Platelets / Q000378:metabolism*; D020520:Brain Infarction / Q000097:blood* / Q000175:diagnosis; D002533:Cerebral Angiography / Q000379:methods; D002543:Cerebral Hemorrhage / Q000097:blood* / Q000175:diagnosis; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D010976:Platelet Count; D011237:Predictive Value of Tests; D014057:Tomography, X-Ray Computed
keywords: Platelets; hemorrhage; stroke; thrombosis