Platelet Function Assessment for Atherothrombotic Patients

January 20, 2011 updated by: National Taiwan University Hospital

Validation of the Clinical Applicability of Various Platelet Function Assessments in High-Risk Atherothrombotic Patients Undergoing Percutaneous Coronary Angioplasty: Phase 4 Study

Background-Despite the pivotal pathogenic role of platelets in atherothrombosis has been widely recognized, there is a striking lack of consensus regarding how to measure platelet function and how to monitor the effects of various antiplatelet drugs. In view of the fact that recurrent ischemic events occurred in 8.5% to 8.8% of patients treated with dual antiplatelet drugs and there is significant inter-individual variability in platelet reactivity, we believe that the importance of platelet function assessment and its clinical implication should not be overlooked.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Unknown

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Methods and Expected Results-In this prospective follow-up study, we will assess the predictive power of different assays of platelet function (PFA-100, plasma levels of von Willebrand factor, P-selectin, soluble CD40 ligand, and myeloid-related protein-8/14, and ADP-induced P-selectin [CD62P] expression on platelets by flow cytometry) before and after high-dose (600 mg) clopidogrel loading, at 3-month follow-up, and at study end on the occurrence of major cardiovascular events (MACE)(death, myocardial infarction, stroke, and coronary revascularization). We will also evaluate the correlations between different assays of platelet function. Based on our previous pilot study which demonstrated that a significant association between collagen-ADP closure time measured by PFA-100 and the occurrence of major cardiovascular events in 130 patients undergoing coronary angioplasty followed up for 6 months, we plan to include 150-200 patients into the present study. The total inclusion period is estimated to be 1 year. Therefore, a total of 2 to 2.5 years will be needed to complete this study. In the first year, we will analyze (1) the correlations between various platelet parameters and coronary angiographic findings; (2) the correlations among different platelet function measurements; and (3) the responsiveness of CADP-CT on high-dose clopidogrel loading.

In the second year, we will (1) analyze the predictability of various platelet parameters, at different point of time (baseline, after clopidogrel loading, at study end), on the occurrence of MACE and (2) establish a risk-prediction schema for patients undergoing coronary angioplasty. A pre-defined threshold value for the collagen-epinephrine closure time is set at 190 s, since this value has been recommended by other investigators to differentiate the presence or absence of aspirin resistance. A pre-defined threshold value for the collagen-ADP closure time is set at 90 s, since we found in our pilot study that this value was associated with the best discriminating ability for identifying patients developing MACE. In the third year, genetic background determining the PFA-100 closure time and levels of plasma markers of platelet activation will be explored by analyzing the relationships between various SNP/haplotype patterns and values of different platelet function assessments.

Clinical Significance-The present study will be the first to explore the clinical role of platelet function assessment both at baseline, after high-dose clopidogrel loading, and at study end. It may give us great insights regarding how to treat high-risk patients adequately with antiplatelet agents.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Anticipated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
150

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.
  • Name: Tzung-Dau Wang, M.D.,Ph.D.
  • Phone Number: 5632 886-2-23123456
  • Email: tdwang@ntu.edu.tw

Study Locations

  • Taiwan
      • Taipei, Taiwan, 100
        • Recruiting
        • Division of Cardiology, Department of Internal Medicine and Department of Medical Imaging, National Taiwan University Hospital
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years to 80 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Coronary artery disease

Exclusion Criteria:

  • History of bleeding diathesis
  • History of drug or alcohol abuse or liver disease
  • Abnormal prothrombin time
  • Abnormal platelet count
  • Serum creatinine >1.5 mg/dl.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Active Comparator: c6
Clopidogrel 600 mg loading
Drug: Clopidogrel
Clopidogrel 600 mg loading

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Time Frame
the occurrence of major cardiovascular events (MACE)(death, myocardial infarction, stroke, and clinically driven target lesion revascularization)
Time Frame: 1 year
1 year

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Time Frame
the correlations between various platelet parameters and coronary angiographic findings
Time Frame: 1 year
1 year
the correlations among different platelet function measurements
Time Frame: 1 year
1 year
the responsiveness of CADP-CT on high-dose clopidogrel loading
Time Frame: 1 year
1 year

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
National Taiwan University Hospital

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Study Chair: Tzung-Dau Wang, M.D.,Ph.D., National Taiwan University Hospital

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
July 1, 2006

Primary Completion (Anticipated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
June 1, 2011

Study Completion (Anticipated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
July 1, 2011

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
August 6, 2007

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 7, 2007

First Posted (Estimate)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
August 8, 2007

Study Record Updates

Last Update Posted (Estimate)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
January 24, 2011

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
January 20, 2011

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
January 1, 2011

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 200612040R

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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