Higher levels of coated-platelets are observed in patients with subarachnoid hemorrhage but lower levels are associated with increased mortality at 30 days

Background: Coated-platelets are procoagulant platelets observed upon dual agonist stimulation with collagen and thrombin. Coated-platelet levels are elevated in non-lacunar ischemic stroke compared to either lacunar stroke or controls. In contrast, coated-platelet levels are decreased in spontaneous intracerebral hemorrhage (ICH) and inversely correlated with bleed size. We now report the first investigation of coated-platelets in patients with subarachnoid hemorrhage (SAH). Methods: Coated-platelet levels were determined in 40 consecutive patients with spontaneous SAH and in 40 controls. Results are reported as percent of cells converted to coated-platelets. Mortality at one month was recorded for all patients. Results: Coated-platelet levels (mean +/- SD) were significantly higher in SAH patients compared to controls (41.8 +/- 11.4% vs. 30.7 12.2%, p < 0.0001). Among all patients, mortality at 1 month was 20% (8 deaths). Patients were analyzed according to tertiles of coated-platelet levels (split at <36.7%, 36.7-46.2%, >46.2%). The 1-month mortality differed significantly between the coated-platelet tertiles (p = 0.01) with 46% mortality (6/13) among patients in the lowest tertile (lowest levels) compared to 143% (2/14) among those in the middle Waite and 0% in the highest tertile. Conclusions: Coated-platelet levels are higher in SAH patients compared to controls. However, lower coated-platelet levels are associated with increased 1-month mortality in SAH patients, a finding compatible with prior observations of an inverse relationship between coated-platelet levels and bleed volume in ICH. The current data support the role played by these prothrombotic platelets in thrombosis or hemorrhage and suggest a potential place for coated-platelet levels in predicting prognosis after SAH. Published by Elsevier B.V.