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Platelet function under aspirin, clopidogrel, and both after ischemic stroke: a case-crossover study.

Armin J Grau·Sven Reiners·Christoph Lichy·Florian Buggle·Andreas Ruf
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Abstract

BACKGROUND AND PURPOSE: Combined antiplatelet agents may offer additive protection over single drugs after stroke. We investigated whether platelet activation is reduced under combined aspirin and clopidogrel compared with each drug alone. METHODS: In a case-crossover study, 31 patients with previous atherothrombotic or lacunar stroke who were treated with aspirin (100 to 300 mg/d) received clopidogrel (75 mg/d) and both aspirin and clopidogrel for 4 weeks. Platelet function in whole blood was studied after each treatment period and in healthy control subjects to assess activation-dependent antigens CD62p and CD63 by flow cytometry and collagen/epinephrine (CEPI-CT) and collagen/ADP (CADP-CT) closure times with the platelet function analyzer PFA-100, which investigates platelet-related function under shear stress. RESULTS: CD62p expression and CD63 expression were not different under the 3 treatment regimens. CD63 but not CD62p expression was lower in control subjects than in stroke patients regardless of the antiplatelet treatment (P<0.05). CEPI-CT was prolonged under aspirin and aspirin plus clopidogrel compared with clopidogrel monotherapy (P<0.0001). CADP-CT was longer under combination therapy than under aspirin (P=0.0009) or clopidogrel (P=0.0074) or in control subjects (P=0.0010), mainly because of strong prolongation in a patient subgroup (28%). CONCLUSIONS: CD63 expression reflecting the release of platelet lysosomes is consistently increased after stroke and incompletely suppressed by treatment with aspirin, clopidogrel, or both. The strong prolongation of CADP-CT under combined aspirin and clopidogrel in a patient subgroup may indicate a lower risk of thrombosis but also a higher risk of hemorrhage. The predictive value of platelet activation parameters requires investigation in prospective studies.

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Antigens, CDAspirinBlood PlateletsBrain IschemiaCase-Control StudiesClopidogrelCross-Over StudiesDrug Therapy, CombinationFemaleFlow CytometryHumansMaleMiddle AgedP-SelectinPlatelet ActivationPlatelet Aggregation InhibitorsPlatelet Membrane GlycoproteinsSecondary PreventionStrokeTetraspanin 30TiclopidineClinical TrialComparative StudyControlled Clinical TrialJournal ArticleResearch Support, Non-U.S. Gov't

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Armin J Grau, Sven Reiners, Christoph Lichy, Florian Buggle, Andreas Ruf. 2003-03-13. Platelet function under aspirin, clopidogrel, and both after ischemic stroke: a case-crossover study.. https://doi.org/10.1161/01.str.0000064326.65899.ac

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