Genetic Variation in Platelet Aggregation

An observational study of Myocardial Infarction, run by Vanderbilt University at 1 site in United States.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Trial summary

The aim of the study is to test whether genetic variation in the alpha 2A adrenergic receptor affects diurnal variation in platelet aggregation. Read more about this study

Who is it for?: Ages 18 to 45 yearsHealthy volunteers can take part
Conditions the study is for: Myocardial Infarction
How many people: 117 participants
Where: 1 siteUnited States
Study dates: Jul 2012to Dec 2016
Phase: Observational
Are there results?: Yes, posted in the registrySummary in the doctors' view

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

Ages 18 to 45 years
All sexes
Healthy volunteers accepted
Adult

Study population: Healthy subjects will be recruited by advertisement and word-of-mouth.

Who may be able to join

Men and women aged 18 - 45 years inclusive.
Women of the above age will be studied between day 1 and day 14 of a normal menstrual cycle.
Subjects must be willing to give informed consent for the study and able to adhere to the study diet and study procedures.
Subjects and immediate extended family up till grandparents will be Caucasians or African Americans only.
Subjects will be free of any clinically significant disease.
Clinical laboratory test (CBC, blood chemistry) will be within acceptable limits.

Who cannot join

Subjects who have taken any antiplatelet, anticoagulant or procoagulant medicines within the last three weeks preceding the study.
Subjects who have taken medications (including over the counter medications) other than oral contraceptives in the past two weeks.
Subjects who smoke or have smoked in the past 3 months.
Subjects who are presently or were formerly a narcotic addict or alcoholic.
Females with a positive pregnancy test.
Females who are breast feeding.

Trial locations and contacts

1 site in 1 country.

United States1 site

the Vanderbilt University General Clinical Research Center
Nashville, Tennessee, 37232

Other trials in United States

About this study

The aim of the study is to test whether genetic variation in the alpha 2A adrenergic receptor affects diurnal variation in platelet aggregation.

Read the detailed description

There is a marked diurnal fluctuation in the occurrence of acute myocardial infarction and sudden death, with peak incidences occurring in the early morning. Platelet aggregation has also been shown to increase in the early morning. The investigators will test the hypothesis that alpha 2a-adrenergic receptor (ADRA2A) genetic variation, specifically haplotype 4, affects platelet aggregation. The investigators will compare diurnal platelet aggregation in haplotype 4 subjects with subjects in the other haplotype families. In addition, the investigators will compare platelet aggregation after the cold pressor test in haplotype 4 with the other haplotype families. If there are no differences among haplotypes, then the haplotypes will be combined to analyze.

Conditions: Myocardial Infarction
Keywords: Myocardial infarction, Platelet aggregation, cold pressor test, Genetics
Medical subject headings: Myocardial Infarction

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

Study groups in NCT01576536
Study group	Role	What they receive
Healthy volunteers		Normal healthy volunteers

What is being measured

The primary outcome is the main question the study is designed to answer.

LogEC50 Platelet Aggregation
EC50 represents the epinephrine concentration that produced 50% of maximal platelet aggregation (representing sensitivity to epinephrine) EC50 values were not normally distributed and were log-transformed for analyses.
Measured: at 6am and 930am

Secondary outcomes (2)

Percentage, Adenosine Diphosphate (ADP) Induced Platelet Aggregation
Blood samples were taken from participants and centrifuged. Adenosine Diphosphate (ADP) at a fixed concentration of 2.5 uM was added. Agonist-induced platelet aggregation was expressed as the percentage aggregation after 6 minutes of stimulation.
Measured: at 6am and 930am
Percentage, Collagen Induced Platelet Aggregation
Blood samples were taken from participants and centrifuged. Collagen at a fixed concentration of 2.5 ug/ml was added. Agonist-induced platelet aggregation was expressed as the percentage aggregation after 6 minutes of stimulation.
Measured: at 6am and 930am

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

Jul 2012Dec 2016

First posted12 Apr 2012 (estimated)
Study startJul 2012
Primary completionDec 2015
Study completionDec 2016

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
Other trials for Myocardial InfarctionStudies of the same condition, open and under way.
What the trial phases meanHow a treatment moves from first tests in people to approval.

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design

Study type: Observational
Observational model: Cohort
Time perspective: Prospective
Enrolment: 117 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT01576536
Sponsor's protocol ID: 111760
Status last verified: Jun 2019
First submitted: 10 Apr 2012
Last updated: 5 Jun 2019
Results posted: Yes, on ClinicalTrials.gov
Data monitoring committee: No
Individual data sharing: Yes: all IDP that underlie results in a publication

Want to know more?

The sponsor has not listed a contact. The official record may have more details.

Talk to your doctor first and take this page with you. Only the study team can confirm whether you can join.

Questions to ask the study team

What is the study trying to find out?
What would I need to do, and how often would I visit?
Could I receive a placebo instead of the treatment?
What are the possible risks and benefits for me?
Will it cost me anything? Are travel or time paid for?
Can I keep seeing my own doctor during the study?
What happens when the study ends?

See locations

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Routine Versus Provisional Distal Perfusion Catheter Placement in Patients Undergoing Mechanical Circulatory Support
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All Myocardial Infarction trials

Study at a glance

From the registry record, last updated by the sponsor on 5 Jun 2019. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: Genetic Variation in Platelet Aggregation
ClinicalTrials.gov ID: NCT01576536
Acronym / sponsor ID: 111760
Conditions: Myocardial Infarction
Keywords: Myocardial infarction, Platelet aggregation, cold pressor test, Genetics
Study type: Observational
Recruitment status: Completed
Enrolment: 117 participants (actual)
Lead sponsor: Vanderbilt UniversityUniversity, hospital or other
Study start: Jul 2012
Primary completion: Dec 2015 (actual)
Study completion: Dec 2016 (actual)
First posted: 12 Apr 2012 (estimated)
Results: Posted 5 Jun 2019

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

The aim of the study is to test whether genetic variation in the alpha 2A adrenergic receptor affects diurnal variation in platelet aggregation.

Detailed description

Study design

Observational model: Cohort
Time perspective: Prospective
Number of arms: 1

Arm	Type	Receives
Healthy volunteers	–	–Normal healthy volunteers

Who may qualify

Ages: 18 to 45 years
Sex: All
Healthy volunteers: Accepted
Age groups: Adult
Study population: Healthy subjects will be recruited by advertisement and word-of-mouth.

Key inclusion criteria (6 listed)

Men and women aged 18 - 45 years inclusive.
Women of the above age will be studied between day 1 and day 14 of a normal menstrual cycle.
Subjects must be willing to give informed consent for the study and able to adhere to the study diet and study procedures.
Subjects and immediate extended family up till grandparents will be Caucasians or African Americans only.
Subjects will be free of any clinically significant disease.

Key exclusion criteria (6 listed)

Subjects who have taken any antiplatelet, anticoagulant or procoagulant medicines within the last three weeks preceding the study.
Subjects who have taken medications (including over the counter medications) other than oral contraceptives in the past two weeks.
Subjects who smoke or have smoked in the past 3 months.
Subjects who are presently or were formerly a narcotic addict or alcoholic.
Females with a positive pregnancy test.

Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.

Primary outcome

LogEC50 Platelet Aggregation
Time frame: at 6am and 930am
EC50 represents the epinephrine concentration that produced 50% of maximal platelet aggregation (representing sensitivity to epinephrine) EC50 values were not normally distributed and were log-transformed for analyses.

2 secondary outcomes

Percentage, Adenosine Diphosphate (ADP) Induced Platelet Aggregation
Time frame: at 6am and 930am
Percentage, Collagen Induced Platelet Aggregation
Time frame: at 6am and 930am

Results and safety

Results posted to the registry on 5 Jun 2019, as reported by the sponsor. Figures are copied from the record, not re-analysed. Full results on ClinicalTrials.gov.

Participant flow

Group	Started	Completed
Healthy Volunteers	117	117

Primary outcome: LogEC50 Platelet Aggregation

Time frame: at 6am and 930am. Mean (Standard Deviation). Unit: nM

Measure	Healthy Volunteers n = 108
LogEC50 at 6am	2.65 (0.49)
LogEC50 at 930am	2.62 (0.44)

Population analysed: outcome data could not be collected on all subjects, since unable to draw enough blood at a particular timepoint

2 secondary outcomes are reported in the full results.

Adverse events

Time frame: Adverse event data was collected from the time participant was admitted to the Clinical Research Center the evening before the study, to the end of the study, a 24 hour period.. Other adverse events reported at 5% frequency or more

Group	Serious adverse events	Other adverse events	Deaths
Healthy Volunteers	1 of 117 (0.9%)	0 of 117 (0%)	Not reported

Limitations and caveats (from the sponsor): Healthy young subjects studied, thus findings may not apply to different populations. Plasma catecholamines are an indirect measure of sympathetic activity--norepinephrine spillover would be more precise, but is technically demanding, not feasible.

Loading the posted results from ClinicalTrials.gov…

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 5 Jun 2019.
Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
Individual participant dataSharing planned: Yes. all IDP that underlie results in a publication

Related trials for Myocardial Infarction

RecruitingObservational study
Mechanisms of Myocardial Injury and Ischemia in Patients With Rapid Atrial Fibrillation
Atrial Fibrillation (AF)
RecruitingObservational study
Changes in Skeletal Muscle Thickness in Patients With Acute Heart Failure
Heart Failure, Muscle Atrophy
Not yet recruitingPhase 3
Cilostazol for Prevention of Recurrent Stroke Trial
Stroke Recurrence, Myocardial Infarction
Recruiting
Routine Versus Provisional Distal Perfusion Catheter Placement in Patients Undergoing Mechanical Circulatory Support
Cardiogenic Shock, Acute Myocardial Infarction of Inferior Wall
Recruiting
Optimal Timing of Staged Complete Revascularization in STEMI With Multivessel Disease (OPTION-STEMI2)
Myocardial Infarction (MI)

Referral and contact

AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.

Michael Stein, MBChB principal investigator

Vanderbilt University Medical Center

1 site in 1 country: see every site and its status.

Questions about this trial

What is this clinical trial studying?

An observational study of Myocardial Infarction, run by Vanderbilt University at 1 site in United States.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 6 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 5 Jun 2019. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

Yes. Results are posted in the registry (first posted 5 Jun 2019). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

LogEC50 Platelet Aggregation (time frame: at 6am and 930am). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT01576536.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 5 Jun 2019.