Abstract T MP116: Coated-Platelets Predict Stroke at 30 days in Patients with Transient Ischemic Attack
Background: Coated-platelets, a subset of procoagulant platelets observed upon dual agonist stimulation with collagen and thrombin, support a robust prothrombinase activity and provide a unique measure of platelet thrombotic potential. Coated-platelet levels are increased both in non-lacunar stroke and transient ischemic attack (TIA) compared to controls free of stroke or TIA. In addition, higher levels in non-lacunar stroke are associated with stroke recurrence. We now examine whether coated-platelet levels predict stroke at 30 days in TIA patients.
Methods: Consecutive patients with a diagnosis of TIA established by a board certified neurologist were enrolled in this pilot study. The diagnosis was consistent with the tissue-based definition of TIA: a transient episode of neurological dysfunction without acute infarction. The absence of infarction was demonstrated by normal brain imaging studies. Those taking anticoagulants or with dementia were excluded. Coated-platelets were determined at baseline and reported as percent of cells converted to coated-platelets. A receiver operating characteristic curve (ROC) analysis was conducted to compare the ability of coated-platelets versus chance alone to predict incident stroke at 30 days.
Results: We enrolled 171 patients. Ten strokes were observed at 30 days. ROC analysis showed significant improvement in the predictive ability of the coated-platelets model compared to chance (AUC: 0.78 ± 0.07 versus 0.50 ± 0, respectively; p < 0.0001). A cut-off of 51.1% for coated-platelet levels yielded a sensitivity of 0.80 (0.55-1.0; 95% CI), specificity of 0.73 (0.66-0.80), positive predictive value of 0.16 (0.06-0.26), and a negative predictive value of 0.98 (0.96-1.0).
Conclusions: Among these subjects with TIA, coated platelet levels <51.1% at time of presentation had a negative predictive value of 98% for stroke at 30 days. These findings suggest a role for coated-platelets in stroke risk stratification following TIA.
Author Disclosures: A. Kirkpatrick: None. A. Vincent: None. G. Dale: None. C. Prodan: Research Grant; Modest; Department of Veterans Affairs Merit Award 1I01CX000340.
- © 2015 by American Heart Association, Inc.