Coated-Platelet Levels and Cerebral Microbleeds in Patients with Non-Lacunar Brain Infarction (P02.185)

Abstract

Objective: To examine the relationship between coated-platelet levels and the presence of cerebral microbleeds in non-lacunar ischemic stroke. Background Microbleeds are increasingly observed neuroimaging findings in patients with cerebrovascular disease. Coated-platelets are a subset of platelets with high procoagulant potential observed upon dual-agonist stimulation with collagen and thrombin. Coated-platelet levels are elevated in patients with non-lacunar ischemic stroke compared to controls, although those patients with lower coated-platelet levels experience more frequent early hemorrhagic transformation. In contrast to brain infarction, patients with spontaneous intracerebral hemorrhage have lower coated-platelet levels, and these levels inversely correlate with bleed size. We, therefore, undertook a study to investigate a relationship between coated-platelet production and the presence of microbleeds in patients with ischemic stroke. Design/Methods: Coated-platelet levels were determined in 110 consecutive patients with a diagnosis of non-lacunar stroke defined by TOAST criteria. Microbleeds were detected using T2*-weighted MRI sequences (1.5 T) based on published criteria. Patients receiving anticoagulation or thrombolytics were excluded. The presence of microbleeds was determined by an experienced stroke neurologist who was blinded to the coated-platelet levels. Individuals performing the coated-platelet assay were not aware of the clinical diagnosis. Results: Among 110 patients with non-lacunar stroke, 22 patients (20%) had microbleeds. Coated-platelet levels (mean±SD) for all patients were 42.9±13.9% (range 3.7-77.6%). Statistical analysis of coated-platelet levels, distributed as tertiles (lowest 3.7-36.2%, middle 36.8-49.2% and highest 49.3-77.6%), showed a significant inverse correlation with the presence of microbleeds (P=0.019). Microbleeds were present in 13/36 patients in the lowest tertile compared to 4/37 in the middle tertile and 5/37 in the highest tertile of coated-platelets. Conclusions: Lower levels of coated-platelets are associated with the presence of microbleeds in patients with non-lacunar ischemic stroke. 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. Supported by: Clinical Science Research & Development Service of the VA Office of Research and Development (award number1I01CX000340) and AHA. Disclosure: Dr. Prodan has nothing to disclose. Dr. Gordon has nothing to disclose. Dr. Dale has nothing to disclose.