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clOpidogrel "resIstaNce" in a Selected Population of Patients at a Tertiary Cardiovascular Center in Trinidad (POINT)

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT03667066
Recruitment Status : Completed
First Posted : September 12, 2018
Last Update Posted : September 27, 2018
Information provided by (Responsible Party):
The University of The West Indies

Brief Summary:
The aim of this study was to determine the prevalence of clopidogrel resistance among a selected group of patients undergoing elective percutaneous coronary intervention and to observe whether there was any south-Asian (Indo-Trinidadian) predilection for HPR considering the well-established epidemiologic trends for accelerated CAD within this subgroup.

Condition or disease Intervention/treatment
Platelet Dysfunction Drug: Clopidogrel

Detailed Description:

Clopidogrel, a second generation oral thienopyridine, remains an integral component of dual antiplatelet therapy (DAPT) in the management of cardiovascular disease (CVD) for almost two decades. Several studies underscore the importance of high on-treatment platelet reactivity (HPR) as a prognosticator for cardiovascular events including stent thrombosis. This phenomenon is often alluded to as "clopidogrel resistance" and yet to be clearly defined. Generally, it reflects the failure to achieve its antiaggregatory effect. Clopidogrel response is both complex and multifactorial, determined by a multitude of intrinsic and extrinsic mechanisms including genetic polymorphisms of the P2Y12 receptor, drug-drug interactions, and clinical factors such as suboptimal dosing regimens, acute coronary syndromes, diabetes mellitus, and possibly smoking.

High pre-treatment platelet reactivity may lead to mitigated clopidogrel-induced antiplatelet effects and are more commonly observed in specific clinical scenarios such as ACS, increased body mass index, and diabetes mellitus, in particular, insulin-dependent diabetes mellitus. Matetzky et al also surmised that nearly one-quarter of ST-segment elevation acute coronary syndrome patients would incur stent thrombosis due to this phenomenon.

Overall, HPR prevalence in various studies is estimated at 5%-44%, however, these are based on largely Caucasian populations and yet to be ascertained in a Caribbean subpopulation. Trinidad and Tobago has an ethnically diverse population with approximately one-third South Asian (Indo-Trinidadian), one-third Caribbean Black (Afro-Trinidadian) and the remaining one-third, mostly interracial and mixed. CVD is currently the leading cause of mortality in Trinidad and Tobago, accounting for up to 60% of all deaths annually.

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Study Type : Observational
Actual Enrollment : 40 participants
Observational Model: Cohort
Time Perspective: Cross-Sectional
Official Title: Prevalence of clOpidogrel "resIstaNce" in a Selected Population of Patients Undergoing Elective Percutaneous Coronary Intervention at a Tertiary Cardiovascular Center in Trinidad: The POINT Pilot Study
Actual Study Start Date : September 1, 2017
Actual Primary Completion Date : January 1, 2018
Actual Study Completion Date : June 1, 2018

Resource links provided by the National Library of Medicine

Intervention Details:
  • Drug: Clopidogrel
    Patients who were on long-term (more than 3 months) of clopidogrel or received a loading dose more than 4 hours prior to elective percutaneous coronary intervention.

Primary Outcome Measures :
  1. Overall prevalence of HPR in the Trinidadian population undergoing elective percutaneous coronary intervention [ Time Frame: 4 months ]

Secondary Outcome Measures :
  1. Prevalence of HPR in the South Asian Trinidadian population undergoing elective percutaneous coronary intervention [ Time Frame: 4 months ]

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Sampling Method:   Probability Sample
Study Population
This is a cross-sectional, open-label (Plavix, Sanofi SA, Gentilly, France, Bristol-Myers Squibb, New York, USA) pilot study aimed to assess high on-treatment platelet reactivity which occurred during the period September 2017 to January 2018. Patients were screened with a stratified permuted block randomization technique which applied to both recruitment days (Monday, Tuesday and Thursday) and patients enrolled at the cardiac catheterization laboratory (cardiac bays 1 to 4) at the investigator's institution (Eric Williams Medical Sciences Complex, Trinidad and Tobago). The clinical research associates were blinded to the allocation assignment and randomization sequence numbers were obtained from SPSS version 24.0 software (IBM SPSS Statistics, New York City, New York, USA). On average, 1-2 patients were enrolled every week for 8 months.

Inclusion Criteria:

  • above 18 years of age
  • diagnosed with stable angina awaiting elective coronary angiography on dual antiplatelet therapy for at least 3 months with aspirin 81 mg per day maintenance dose and "brand name" clopidogrel 75 mg per day maintenance dose

Exclusion Criteria:

  • generic clopidogrel, i.e. not "brand name,"
  • recent acute coronary syndrome within 6 months
  • active bleeding
  • prior cerebrovascular event
  • clinical instability after an index event
  • use of an oral anticoagulation agent (coumadin derivative or other anticoagulant therapy (such as dabigatran, rivaroxaban or apixaban)
  • platelet count < 100 x 106/µL
  • hemoglobin < 10 g/dL
  • serum creatinine > 2.5 mg/dL

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT03667066

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Trinidad and Tobago
Eric Williams Medical Sciences Complex
Port Of Spain, North, Trinidad and Tobago, 00000
Sponsors and Collaborators
The University of The West Indies
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Principal Investigator: Naveen A Seecheran, MBBS MSc The University of The West Indies
Publications automatically indexed to this study by Identifier (NCT Number):
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Responsible Party: The University of The West Indies Identifier: NCT03667066    
Other Study ID Numbers: CEC057/11/15
First Posted: September 12, 2018    Key Record Dates
Last Update Posted: September 27, 2018
Last Verified: September 2018
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: Yes
Plan Description: All information will be shared with requesting parties.
Supporting Materials: Study Protocol
Statistical Analysis Plan (SAP)
Informed Consent Form (ICF)
Clinical Study Report (CSR)
Analytic Code
Time Frame: It will be openly available until 5 years after the completion of the study.
Access Criteria: Please contact the Principal Investigator for the requested information.

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Studies a U.S. FDA-regulated Drug Product: Yes
Studies a U.S. FDA-regulated Device Product: No
Product Manufactured in and Exported from the U.S.: No
Additional relevant MeSH terms:
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Platelet Aggregation Inhibitors
Purinergic P2Y Receptor Antagonists
Purinergic P2 Receptor Antagonists
Purinergic Antagonists
Purinergic Agents
Neurotransmitter Agents
Molecular Mechanisms of Pharmacological Action
Physiological Effects of Drugs