Monitoring of biological response to clopidogrel after treatment for non-cardioembolic ischemic stroke or transient ischemic attack.

ABSTRACT: BACKGROUND AND PURPOSE:Biological response to clopidogrel prescribed after a non-cardioembolic ischemic stroke or transient ischemic attack (TIA) has been little studied. The aim of our study (AAPIX) was to assess this response and investigate the agreement between different biological assays in revealing poor responders. METHODS:Patients hospitalized following a non-cardioembolic ischemic stroke or transient ischemic attack (TIA) and prescribed clopidogrel were consecutively included from September 2013 to November 2015 in the Stroke Center of Saint-Etienne Hospital. Blood was drawn after 5 to 8 days of standard-dose clopidogrel. Light transmission aggregometry (LTA) and flow cytometric assays, using vasodilator-stimulated phosphoprotein [VASP] and CD62P, were accomplished for all patients. Transmission electron microscopy (TEM) was performed for a poor clopidogrel-responder and for a patient with discordant platelet assay results (platelet reactivity index (PRI) >50% and maximum platelet aggregation <70%), after activation with adenosine diphosphate (ADP) 10 µM. RESULTS:72 patients were included. According to LTA, VASP assay and CD62P test results, 65%, 71% and 0% of patients, respectively, had a low response to clopidogrel, indicating poor agreement between these assays. Images of ADP-activated platelet samples from a patient manifesting a low response to clopidogrel and from a patient with discordant platelet assay results showed an ultrastructural pattern typical of activation and a state of slight activation, respectively. CONCLUSIONS:Platelet function results obtained using different assays for patients having experienced a non-cardioembolic ischemic stroke or TIA were discordant. Transmission electron microscopy could be useful in certain clinical contexts when platelet function assay results disagree.

SUBMITTER: Varvat J 

PROVIDER: S-EPMC6789282 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature