Cerebral microbleeds in nonlacunar brain infarction are associated with lower coated-platelet levels.

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.