Related Experiment Video

Updated: Jun 1, 2026

Microfluidics in Assessing Platelet Function
06:47

Microfluidics in Assessing Platelet Function

Published on: November 8, 2024

The influencing factors for clopidogrel-mediated platelet inhibition are assay-dependent

Thomas Gremmel1, Sabine Steiner, Daniela Seidinger

  • 1Department of Internal Medicine II, Medical University of Vienna, Vienna, Austria. thomas.gremmel@meduniwien.ac.at

Thrombosis Research
|May 31, 2011
PubMed

Insights

Clopidogrel response varies based on the platelet function test used. Factors influencing clopidogrel

Area of Science:

  • Pharmacology
  • Cardiovascular Medicine
  • Clinical Chemistry

Background:

  • Previous studies on clopidogrel response have used limited test systems, yielding inconsistent results.
  • The identification of factors influencing clopidogrel's antiplatelet effect may differ across various platelet function assays.
  • Understanding assay-dependent variability is crucial for accurate clopidogrel therapy monitoring.

Purpose of the Study:

  • To investigate whether factors influencing clopidogrel-mediated platelet inhibition are dependent on the specific assay used.
  • To compare the impact of various clinical and laboratory variables on platelet reactivity across multiple platelet function tests.

Main Methods:

  • Adenosine diphosphate (ADP)-inducible platelet reactivity was assessed in 288 patients post-angioplasty using five assays: LTA, VerifyNow P2Y12, VASP, MEA, and Impact-R.
  • Univariate and multivariate regression analyses evaluated the influence of patient demographics, comorbidities, and concomitant medications on clopidogrel response.
  • Key variables included age, BMI, diabetes, smoking, hypertension, hyperlipidemia, C-reactive protein, platelet count, creatinine, and use of CCBs, statins, PPIs, beta-blockers, ACE inhibitors, and ARBs.

Main Results:

  • No single influencing variable was consistently associated with clopidogrel response across all tested assays.
  • Age ≥ 75 and calcium-channel blocker (CCB) use were linked to higher platelet reactivity by LTA and VerifyNow P2Y12.
  • Body mass index (BMI) showed a linear association with platelet reactivity in VASP and MEA assays, while platelet count had conflicting associations in MEA and Impact-R.

Conclusions:

  • The factors influencing platelet reactivity during clopidogrel therapy are significantly assay-dependent.
  • This assay variability highlights the need for careful interpretation of platelet function test results in clinical practice.
  • Future research should consider assay-specific factors when evaluating clopidogrel response and its clinical implications.
Abstract

More Related Videos

Procoagulant Platelet Characterization by Measuring Phosphatidylserine Exposure and Microvesicle Release from Human Purified Platelets05:49

Procoagulant Platelet Characterization by Measuring Phosphatidylserine Exposure and Microvesicle Release from Human Purified Platelets

Published on: November 29, 2024

Preparation of Washed Human Platelets for Quantitative Metabolic Flux Studies07:06

Preparation of Washed Human Platelets for Quantitative Metabolic Flux Studies

Published on: January 10, 2025

Related Concept Videos

Antiplatelet Drugs: Prostaglandin Synthesis, P2Y12 and Glycoprotein IIb/IIIa Inhibitors01:20

Antiplatelet Drugs: Prostaglandin Synthesis, P2Y12 and Glycoprotein IIb/IIIa Inhibitors

Antiplatelet drugs emerge as frontline defenders against the insidious threat of thromboembolic diseases, where abnormal clots obstruct vital blood vessels. These drugs stand as bulwarks, inhibiting platelet aggregation and clot formation, thereby mitigating the risk of life-threatening conditions like myocardial infarction, coronary artery disease, and thrombotic strokes.
Prostaglandin synthesis inhibitors, exemplified by the widely known aspirin, wield their power by irreversibly acetylating...
Formation of the Platelet Plug01:22

Formation of the Platelet Plug

The platelet phase, the second stage of hemostasis, commences around 15-20 seconds after an injury. It follows and overlaps with the vascular phase, during which blood vessels constrict to minimize blood loss.
As the injured blood vessel contracts, endothelial cells undergo contraction, revealing collagen fibers in the basement membrane and underlying connective tissue. Furthermore, the plasma membrane of endothelial cells becomes adhesive, preparing the site for platelet adhesion. Platelets...
Factors Affecting Protein-Drug Binding: Drug-Related Factors01:18

Factors Affecting Protein-Drug Binding: Drug-Related Factors

Drug binding to proteins is a complex phenomenon influenced by various drug-related factors, each playing a significant role in the interaction between drugs and proteins within the body.
One crucial factor in drug-protein binding is the drug's lipophilicity or its affinity for fat. More lipophilic drugs tend to have higher binding extents. For example, highly lipophilic drugs like cloxacillin exhibit substantial protein binding, with as much as 95% of the drug binding to proteins. In contrast,...
Pharmacogenetic Phenotypes: Alterations in Pharmacokinetics, Drug Targets and Biologic Milieu01:29

Pharmacogenetic Phenotypes: Alterations in Pharmacokinetics, Drug Targets and Biologic Milieu

Genetic variations significantly influence drug response through pharmacokinetics, receptor interactions, and biologic milieu modifications. Pharmacokinetic alterations impact drug metabolism and clearance, affecting efficacy and toxicity. Variants in drug-metabolizing enzymes, such as CYP2C9 and CYP2C19, alter drug activation and elimination. For example, CYP2C9 loss-of-function variants require lower warfarin doses to prevent excessive bleeding, while CYP2C19 variants reduce clopidogrel...
Factors Affecting Protein-Drug Binding: Drug Interactions01:23

Factors Affecting Protein-Drug Binding: Drug Interactions

Drug interactions are a critical aspect of pharmacology and can occur when two or more drugs compete for the same binding site. This competition can result in one drug displacing another, altering the effect of the displaced drug. Drug interactions are complex processes that rely heavily on how much of the displacer drug is present and how strongly it can bind to the same sites as the displaced drug.
Displacement interactions can have varying outcomes, ranging from toxicity to virtually...
Factors Affecting Protein-Drug Binding: Protein-Related Factors01:20

Factors Affecting Protein-Drug Binding: Protein-Related Factors

Drug binding to proteins is a key aspect of pharmacokinetics and can influence a drug's distribution, absorption, and elimination in the body. Several factors, including the drug's physiochemical properties, protein concentration, disease states, and the number of binding sites on the protein, influence this process.
The physicochemical properties of a drug play a significant role in its ability to bind to proteins. Lipophilic drugs, which dissolve in fats, oils, and lipids, can be bound by...