Clinical Significance of Platelet Reactivity on Clopidogrel During Off-pump Coronary Artery Bypass

Study Overview
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Brief Summary
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Objective: To evaluate the early and late prognoses of patients according to platelet reactivity after clopidogrel administration and determine whether the measurement of platelet inhibition predicted 1-year clinical outcomes after off-pump coronary bypass (OPCAB) Study design Prospective, observational, single-center study Subjects with OPCAB surgery who meet all inclusion and exclusion criteria will be enrolled. Platelet reactivity after 7-days clopidogrel treatment from the day of surgery will be measured by VerifyNow system. Dual antiplatelet therapy including aspirin and clopidogrel will be administered for 1 year after surgery and subjects will be followed-up for 1 year about primary endpoint. Cutoff value of P2Y12 reactivity units (PRUs) for primary endpoint will be assessed and the cohort will be divided by the PRU cutoff value (low/high platelet reactivity groups). The primary and secondary endpoints will be compared between two groups

Conditions
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Coronary Artery Disease

Intervention / Treatment
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* Drug: Dual antiplatelet therapy including aspirin and clopidogrel after off-pump coronary bypass surgery


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients with indications for surgical myocardial revascularization Patients who undergo off-pump coronary artery bypass Age between 19 80 years Patients with signed informed consent Exclusion Criteria: Patients with combined surgery with coronary bypass grafting On-pump conversion Patients with moderate renal dysfunction (creatinine>2.0mg/dl) or need for dialysis Patients with chronic treatment with proton pump inhibitors Patients with preoperative bleeding Thrombocytopenia (Platelet count 70,000/ml) Re-do surgery Early death before the measurement of platelet reactivity

Ages Eligible for Study
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Minimum Age: 19 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Low platelet reactivity group<br>Platelet reactivity will be measured after 7-days treatment of clopidogrel by VerifyNow system and the cohort will be divided by two group according to P2Y12 reactivity unit (PRU) cutoff value. Receiver operating characteristic (ROC) curves will be plotted to assess the optimal PRU cutoff value for differentiating between patients with and without subsequent MACEs after 1 year of follow-up. Low platelet reactivity indicates good response to clopidogrel and high platelet reactivity, resistance to clopidogrel. Groups will be Low platelet reactivity group and High platelet reactivity group | Drug: Dual antiplatelet therapy including aspirin and clopidogrel after off-pump coronary bypass surgery<br>* aspirin 100mg/day and clopidogrel 75mg/day, PO, from the day of surgery for 1 year<br>|
| high platelet reactivity group<br>Platelet reactivity will be measured after 7-days treatment of clopidogrel by VerifyNow system and the cohort will be divided by two group according to P2Y12 reactivity unit (PRU) cutoff value. Receiver operating characteristic (ROC) curves will be plotted to assess the optimal PRU cutoff value for differentiating between patients with and without subsequent MACEs after 1 year of follow-up. Low platelet reactivity indicates good response to clopidogrel and high platelet reactivity, resistance to clopidogrel. Groups will be Low platelet reactivity group and High platelet reactivity group | Drug: Dual antiplatelet therapy including aspirin and clopidogrel after off-pump coronary bypass surgery<br>* aspirin 100mg/day and clopidogrel 75mg/day, PO, from the day of surgery for 1 year<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Major adverse cardiovascular events (MACEs) | The primary endpoint of the study was the 1-year incidence of MACEs, which included the following: (1) cardiac death, defined as death in the presence of acute coronary syndrome, sudden cardiac arrest with documented cardiac arrhythmia, or refractory congestive heart failure; 2) nonfatal MI; and (3) target vessel revascularization in relation to platelet reactivity as measured by the VerifyNow system. | 1 year after off-pump coronary bypass surgery | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Platelet activity, CABG, off-pump surgery