Platelet Reactivity After CABG

Platelet Activation, Reactivity, and Inflammation After Coronary Bypass Surgery In Patients Treated With Ticagrelor or Clopidogrel

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 Overview

• Status: Completed
• Conditions: Acute Coronary Syndrome

• Study Type: Observational
• Enrollment (Actual): 18

Contacts and Locations

Study Locations

• United States
  • Vermont
    • Burlington, Vermont, United States, 05401
      • University of Vermont Medical Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• 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.

Description

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

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
clopidogrel; previous treatment with clopidogrel
ticagrelor; previous treatment with ticagrelor

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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.	16-24 hours after CABG

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
platelet-leukocyte aggregates	We will identify the prevalence of platelet-leukocyte aggregates - a marker of platelet activation in vivo	16-24 hours after CABG
platelet microparticles	We will quantify the prevalence of platelet microparticles, reflecting platelet activation in vivo	16-24 hours after CABG
cytokine/chemokine array	We will quantify the concentration of common cytokines and chemokines.	16-24 hours after CABG

Collaborators and Investigators

• Sponsor: University of Vermont

Study record dates

Study Major Dates

• Study Start: May 1, 2013
• Primary Completion (Actual): September 1, 2015
• Study Completion (Actual): September 1, 2015

Study Registration Dates

• First Submitted: February 13, 2013
• First Submitted That Met QC Criteria: February 14, 2013
• First Posted (Estimate): February 15, 2013

Study Record Updates

• Last Update Posted (Estimate): September 22, 2015
• Last Update Submitted That Met QC Criteria: September 20, 2015
• Last Verified: September 1, 2015

More Information

Terms related to this study

• Keywords: ticagrelor; platelet function; platelet reactivity; Coronary artery bypass surgery; receptor binding; reversible binding
• Additional Relevant MeSH Terms: Myocardial Ischemia; Heart Diseases; Cardiovascular Diseases; Vascular Diseases; Acute Coronary Syndrome
• Other Study ID Numbers: ISSBRIL0095