MedDataX Logo

Platelet Function Monitoring in Patients Treated With Clopidogrel at the Time of Primary Percutaneous Coronary Angioplasty

NCT ID: NCT00827346

Last Updated: 2011-04-29

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

Get a concise snapshot of the trial, including recruitment status, study phase, enrollment targets, and key timeline milestones.

Recruitment Status

COMPLETED

Clinical Phase

PHASE2/PHASE3

Total Enrollment

100 participants

Study Classification

INTERVENTIONAL

Study Start Date

2009-01-31

Study Completion Date

2011-04-30

Brief Summary

Review the sponsor-provided synopsis that highlights what the study is about and why it is being conducted.

Platelets are a major component of clot formation which can lead to clotting events such as heart attack. During treatment for a heart attack, doctors try to remove this blockage as quickly as possible so that the heart can recover and start to work properly again. The standard of care at the Heart Institute for patients having a heart attack is a procedure called a Percutaneous Coronary Angioplasty. A drug called Clopidogrel (Plavix) is routinely used prior to the angioplasty to prevent blood clots. Patients usually remain on Clopidogrel for at least one year following the angioplasty. Clopidogrel works by preventing the blood from forming sticky substances called platelets, which clump together to form clots. Despite the routine use of Clopidogrel, some patients still return to the hospital with another heart attack, or with more chest pain. There is a growing body of evidence that recurrence of these complications may be attributed to some patients having a poor response to Clopidogrel.

This pilot study will examine how platelets react to different doses of Clopidogrel given to patients having a heart attack.

Detailed Description

Dive into the extended narrative that explains the scientific background, objectives, and procedures in greater depth.

Platelets are a major component of clot formation which can lead to thrombotic events. Antiplatelet agents have been found to reduce cardiovascular events in different clinical settings. The commonest agent that has been used is aspirin which works by inhibiting the cyclooxygenase pathway within the platelet and consequently preventing the release of tromboxane A2. A second group of agents called thienopyridines can inhibit platelets by blocking the P2Y12 receptor. Clopidogrel (Plavix) is currently a widely used thienopyridine that has been used for the treatment of patients presenting with the acute coronary syndrome and patients undergoing percutaneous coronary angioplasty (PCI). Antiplatelet therapy has reduced the occurrence of thrombotic events following PCI, including myocardial infarction and stent thrombosis. However, despite dual therapy with aspirin and clopidogrel, a significant number of patients continue to experience cardiovascular events. There is a now growing body of evidence that recurrence of ischemic complications may be attributed to poor response to clopidogrel and that persistence of enhanced platelet reactivity despite the use of clopidogrel is believed to be clinically relevant.1 The mechanisms leading to poor clopidogrel effects are not fully explained.

Our pilot study will use the VerifyNow device as an ex vivo method to measure platelet inhibition in patients treated with clopidogrel in the setting of STEMI. Since July 2004, the standard of care at the University of Ottawa Heart Institute for the treatment of STEMI has been primary PCI in which all patients receive aspirin 160 mg po either in the field or on arrival in the emergency department and clopidogrel 600 mg po given on arrival to the hospital. Little is known of the pharmacokinetics of clopidogrel in the setting of STEMI. Clopidogrel must be absorbed and activated by the liver to be effective. The physiological mechanisms for these steps may be greatly disturbed in patients presenting with STEMI. Therefore, the purpose of this study will be to examine the degree of platelet inhibition at various time points in this select patient population using the current 600 mg dose of clopidogrel and comparing this dose to other doses of clopidogrel to determine the optimal loading dose in the context of STEMI.

Conditions

See the medical conditions and disease areas that this research is targeting or investigating.

Platelet Reactivity

Study Design

Understand how the trial is structured, including allocation methods, masking strategies, primary purpose, and other design elements.

Allocation Method

RANDOMIZED

Intervention Model

FACTORIAL

Primary Study Purpose

DIAGNOSTIC

Blinding Strategy

NONE

Study Groups

Review each arm or cohort in the study, along with the interventions and objectives associated with them.

Group 1

600-mg double dose

Group Type ACTIVE_COMPARATOR

Clopidogrel

Intervention Type DRUG

600 mg now

Group 2

600/600-mg double loading dose (first dose 600 mg given immediately upon arrival at the hospital and the second dose 600 mg, 3 hours after the first loading dose for a total of 900 mg

Group Type ACTIVE_COMPARATOR

Clopidogrel

Intervention Type DRUG

600 mg now and 600 mg in 3 hours

Group 3

Clopidogrel 900mg

Group Type ACTIVE_COMPARATOR

Clopidogrel

Intervention Type DRUG

900 mg now

Group 4

First dose 600 mg given immediately upon arrival at the hospital and the second dose 300 mg, 3 hours after the first loading dose for a total of 900 mg

Group Type ACTIVE_COMPARATOR

Clopidogrel

Intervention Type DRUG

600 mg now and 300 mg in 3 hours

Interventions

Learn about the drugs, procedures, or behavioral strategies being tested and how they are applied within this trial.

Clopidogrel

600 mg now

Intervention Type DRUG

Clopidogrel

600 mg now and 600 mg in 3 hours

Intervention Type DRUG

Clopidogrel

900 mg now

Intervention Type DRUG

Clopidogrel

600 mg now and 300 mg in 3 hours

Intervention Type DRUG

Eligibility Criteria

Check the participation requirements, including inclusion and exclusion rules, age limits, and whether healthy volunteers are accepted.

Inclusion Criteria

1. Ischemic chest discomfort of greater than 30 minutes duration
2. Onset of chest pain less than 12 hrs prior to entry into the study
3. ST segment elevation of \> 1 mm (0.1 mV) in two or more contiguous electrocardiographic leads (on a standard 12 lead ECG) or left bundle branch block not known to be old

Exclusion Criteria

1. Active bleeding
2. GI or GU bleed within 2 weeks, or any major bleeding episode within 2 weeks
3. Stroke within 90 days or intracranial bleeding at any time
4. Major surgery or trauma within the past six weeks
5. Uncontrolled hypertension (SBP \> 200 mm Hg and/or DBP \> 110 mm Hg despite treatment)
6. Prolonged (\>10 min) cardiopulmonary resuscitation
7. Inadequate vascular access
8. PCI within the last 30 days
9. Thrombolytic agents within the preceding 7 days
10. GP IIb/IIIa antagonists within the preceding 7 days
11. Coagulation disorder (i.e. INR \>2.0, platelets \<100,000 / mm3, or hematocrit \<30%)
12. Current warfarin treatment
13. A subcutaneous therapeutic dose of any LMWH within 12 hours
14. Intolerance to aspirin or clopidogrel
15. Patient already on chronic clopidogrel therapy
16. Other medical condition that is likely to result in death within 12 months
17. Participation in a study with another investigational device or drug \< four weeks
18. Pregnancy
19. Known severe renal impairment (creatinine clearance rate of less than 30 ml per minute)
20. Sustained hypotension defined as SBP \< 80 mmHg or the need for IV inotropes and/or intraaortic balloon counterpulsation to support the blood pressure
21. Known severe contrast (dye) allergy
22. Inability to provide informed consent
Eligible Sex

ALL

Accepts Healthy Volunteers

No

Sponsors

Meet the organizations funding or collaborating on the study and learn about their roles.

Ottawa Heart Institute Research Corporation

OTHER

Sponsor Role lead

Responsible Party

Identify the individual or organization who holds primary responsibility for the study information submitted to regulators.

UOHI

Principal Investigators

Learn about the lead researchers overseeing the trial and their institutional affiliations.

Michel R Le May, MD FRCPC FACC

Role: PRINCIPAL_INVESTIGATOR

Ottawa Heart Institute Research Corporation

Locations

Explore where the study is taking place and check the recruitment status at each participating site.

University of Ottawa Heart Institute

Ottawa, Ontario, Canada

Site Status

Countries

Review the countries where the study has at least one active or historical site.

Canada

Other Identifiers

Review additional registry numbers or institutional identifiers associated with this trial.

2008239-01H

Identifier Type: -

Identifier Source: secondary_id

MRL-A2

Identifier Type: -

Identifier Source: org_study_id