Abstract WMP113: Coated-Platelet Levels are Elevated in Subarachnoid Hemorrhage and Inversely Associated with Mortality at 30 Days
Background: 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 non-lacunar ischemic stroke compared to either lacunar stroke or controls. In contrast, coated-platelet levels are decreased in patients with spontaneous intracerebral hemorrhage (ICH) and inversely correlated with bleed size. We now report the first investigation of coated-platelet production in patients with subarachnoid hemorrhage (SAH).
Methods: Coated-platelet levels were determined in 38 consecutive patients with non-traumatic SAH within 48 hours from symptom onset and in 40 controls frequency-matched for gender, race and age. Results are reported as percent of cells converted to coated-platelets. Mortality at 1 month was obtained through chart reviews or telephone interviews. Baseline characteristics were compared either with a t-test for continuous measures or a Chi-square test for categorical measures.
Results: Coated-platelet levels (mean±SD) were significantly higher in patients with SAH compared to controls (41.0±10.7% vs. 30.0±12.1%, p<0.0001). No differences were detected between patients and controls for demographics, medication use or pertinent comorbidities (p values >0.17). Among all patients, mortality at 1 month was 21% (8 deaths). Patients were then analyzed according to tertiles of coated-platelet levels (split at ≤36.6%, 36.6-45.5%, >45.6%). The 1-month mortality differed significantly between the coated-platelet tertiles (p=0.019, Fisher’s exact test), with 50% mortality (6/12) among patients in the lowest tertile (lowest levels) compared to 7.7% (1/13) among those in the middle and highest tertiles.
Conclusions: Coated-platelet levels are elevated in SAH compared to controls for reasons not currently clear. However, the association between lower coated-platelet levels and mortality in SAH patients is compatible with prior observations made in ICH. These data also provide further evidence of the role played by these prothrombotic platelets in events leading to thrombosis or hemorrhage. Supported by Award 1I01CX000340 from the Clinical Science R&D Service of the VA ORD (Prodan)
- © 2012 by American Heart Association, Inc.