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

The University of The West Indies40 enrolled

Overview

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.

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.

Study Type

OBSERVATIONAL

Enrollment

Conditions

Platelet Dysfunction

Interventions

ClopidogrelDRUG

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.

Eligibility

Sex: ALLMin age: 18 Years

Medical Language ↔ Plain English

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

Locations (1)

Eric Williams Medical Sciences Complex

Port of Spain, North, Trinidad and Tobago

Outcomes

Primary Outcomes

Overall prevalence of HPR in the Trinidadian population undergoing elective percutaneous coronary intervention

Time frame: 4 months

Secondary Outcomes

Prevalence of HPR in the South Asian Trinidadian population undergoing elective percutaneous coronary intervention

Time frame: 4 months

Data from ClinicalTrials.gov

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