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Dual Antiplatelet Therapy in Patients With Aspirin Resistance Following Coronary Artery Bypass Grafting

NCT01159639 · Status: COMPLETED · Phase: PHASE4 · Type: INTERVENTIONAL · Enrollment: 200

Last updated 2013-08-28

No results posted yet for this study

Summary

Reactive platelet hyperactivity following coronary artery bypass grafting (CABG) might lead to thrombotic complications and major ischemic cardiac events. The aim of this study is to evaluate the changes in platelet reactivity following CABG and to clarify a potentially beneficial effect of dual antiplatelet therapy in the group of patients with documented aspirin resistance following CABG. Platelet function will be assessed by multiple electrode aggregometry. Aortocoronary vein graft disease is comprised of three distinct but interrelated pathological processes: thrombosis, intimal hyperplasia and atherosclerosis. Early vein thrombosis is a major cause of vein graft attrition during the first month after CABG.

Bypass patency can be improved with antiplatelet therapy which is the mainstay of treatment for patients after CABG. A beneficial effect of acetylsalicylic acid (ASA) on vein graft patency has been previously shown. Some patients experience thrombotic events despite continuous aspirin administration after CABG. The investigators hypothesized that low responsiveness to aspirin might be a precipitating factor for adverse thrombotic events following CABG.

Low responsiveness to ASA, as assessed by platelet function tests, varies widely among patients. The etiology of postoperative platelet hyperactivity remains to be elucidated.

In this study a new point-of-care assay named multiple electrode aggregometry (MEA) using a device called Multiplate analyzer (Dynabyte, Munich, Germany) has been utilized. It allows for rapid and standardized assessment of platelet function parameters.

This is a prospective randomized trial. The aim of the study is to document whether introduction of dual antiplatelet therapy in patients with ASA resistance will lead to a lower incidence of major adverse cardiac events (MACE) at a six month follow up. The composite endpoint will include death, non-fatal myocardial infarction, stroke and cardiac rehospitalization. All patients will receive 300 mg of ASA starting 6 hours after surgery, provided that the chest tube output is minimal. On postoperative day 4 their platelet function will be assessed using the above mentioned MEA. The patients found to be aspirin resistant will then undergo the process of randomization. The first arm will include patients with ASA resistance in whom no additional antiaggregation will be administered. In the second arm the investigators will include patients who were randomized to receive 75 mg of clopidogrel in addition to the standard antiplatelet regimen of 300 mg of ASA.

Platelet function monitoring allows for individual tailoring of the antiplatelet therapy. The goal of this study is to define whether this strategy will lead to improved patient outcomes. Both major and minor bleeding complications will be strictly monitored and reported.

Conditions

Interventions

DRUG

Clopidogrel

patients with inappropriate response to aspirin 300 mg after CABG, assessed by multiple electrode aggregometry are randomized to receive clopidogrel 75 mg daily dose

Sponsors & Collaborators

  • University of Zagreb

    lead OTHER

Study Design

Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
NONE
Model
PARALLEL

Eligibility

Min Age
18 Years
Sex
ALL
Healthy Volunteers
No

Timeline & Regulatory

Start
2010-06-30
Primary Completion
2013-02-28
Completion
2013-02-28

Countries

  • Croatia

Study Locations

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Entities

Diseases

Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT01159639 on ClinicalTrials.gov