Patients who have a heart attack are regularly treated with either clopidogrel or ticagrelor. In a large clinical trial, treatment with ticagrelor before coronary bypass surgery (CABG) was associated with a lower risk of death than treatment with clopidogrel. The reason for this difference cannot be explained on the basis of the study. One possible explanation is that the reversible binding of ticagrelor is advantageous because when new platelets are released, they are inhibited by the drug. Because clopidogrel binds irreversibly it cannot redistribute. The investigators will recruit patients who are scheduled for surgery after an acute coronary syndrome who have been treated with either ticagrelor or clopidogrel. After the patient provides informed consent, the investigators will review their medical record,record information and on the day after surgery the investigators will take one sample of blood. That blood will be analyzed for evidence of platelet activation (platelet microparticles, and platelet-leukocyte aggregates), the reactivity of young platelets, and the concentration of inflammatory cytokines. The investigators hypothesize that the evidence of platelet activation (platelet microparticles and platelet-leukocyte aggregates) and the reactivity of young platelets will be less in patients who have been treated previously with ticagrelor.
Study Type
OBSERVATIONAL
Enrollment
18
University of Vermont Medical Center
Burlington, Vermont, United States
reactivity of juvenile platelets
We will use flow cytometry to identify juvenile platelets and assess their likelihood to activate in response to a submaximal concentration of agonist.
Time frame: 16-24 hours after CABG
platelet-leukocyte aggregates
We will identify the prevalence of platelet-leukocyte aggregates - a marker of platelet activation in vivo
Time frame: 16-24 hours after CABG
platelet microparticles
We will quantify the prevalence of platelet microparticles, reflecting platelet activation in vivo
Time frame: 16-24 hours after CABG
cytokine/chemokine array
We will quantify the concentration of common cytokines and chemokines.
Time frame: 16-24 hours after CABG
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