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Platelet Reactivity After CABG

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT01793597
Recruitment Status : Completed
First Posted : February 15, 2013
Last Update Posted : September 22, 2015
Information provided by (Responsible Party):
David J. Schneider, MD, University of Vermont

Brief Summary:
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.

Condition or disease
Acute Coronary Syndrome

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Study Type : Observational
Actual Enrollment : 18 participants
Observational Model: Cohort
Time Perspective: Prospective
Official Title: Platelet Activation, Reactivity, and Inflammation After Coronary Bypass Surgery In Patients Treated With Ticagrelor or Clopidogrel
Study Start Date : May 2013
Actual Primary Completion Date : September 2015
Actual Study Completion Date : September 2015

Resource links provided by the National Library of Medicine

previous treatment with clopidogrel
previous treatment with ticagrelor

Primary Outcome Measures :
  1. reactivity of juvenile platelets [ Time Frame: 16-24 hours after CABG ]
    We will use flow cytometry to identify juvenile platelets and assess their likelihood to activate in response to a submaximal concentration of agonist.

Secondary Outcome Measures :
  1. platelet-leukocyte aggregates [ Time Frame: 16-24 hours after CABG ]
    We will identify the prevalence of platelet-leukocyte aggregates - a marker of platelet activation in vivo

  2. platelet microparticles [ Time Frame: 16-24 hours after CABG ]
    We will quantify the prevalence of platelet microparticles, reflecting platelet activation in vivo

  3. cytokine/chemokine array [ Time Frame: 16-24 hours after CABG ]
    We will quantify the concentration of common cytokines and chemokines.

Biospecimen Retention:   Samples Without DNA
Platelets and leukocytes will be evaluated acutely. Plasma will be stored for cytokine and chemokine analysis.

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Sampling Method:   Non-Probability Sample
Study Population
Patients with acute coronary syndrome who based on clinical indications require urgent CABG. CABG is scheduled for clinical indications within 48 hours. Previous treatment with clopidogrel or ticagrelor.

Inclusion Criteria:

  • Acute coronary syndrome, CABG, within 48 hours of last dose of clopidogrel or ticagrelor, treatment with aspirin

Exclusion Criteria:

  • Treatment with an antiplatelet agent other than aspirin, clopidogrel, or ticagrelor, Acute or chronic hematologic disorder including a preoperative Hgb less than 10 g/dl or platelet count less than 100,000/mm3, Moderate or severe renal insufficiency (glomerular filtration rate less than 60 ml/min), Active infection, Active malignancy, Unable/unwilling to provide informed consent

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT01793597

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United States, Vermont
University of Vermont Medical Center
Burlington, Vermont, United States, 05401
Sponsors and Collaborators
University of Vermont

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Responsible Party: David J. Schneider, MD, Professor Of Medicine, Director of Cardiology, University of Vermont Identifier: NCT01793597    
Other Study ID Numbers: ISSBRIL0095
First Posted: February 15, 2013    Key Record Dates
Last Update Posted: September 22, 2015
Last Verified: September 2015
Keywords provided by David J. Schneider, MD, University of Vermont:
Coronary artery bypass surgery
platelet function
receptor binding
platelet reactivity
reversible binding
Additional relevant MeSH terms:
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Acute Coronary Syndrome
Myocardial Ischemia
Heart Diseases
Cardiovascular Diseases
Vascular Diseases
Platelet Aggregation Inhibitors
Purinergic P2Y Receptor Antagonists
Purinergic P2 Receptor Antagonists
Purinergic Antagonists
Purinergic Agents
Neurotransmitter Agents
Molecular Mechanisms of Pharmacological Action
Physiological Effects of Drugs