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Slow response to clopidogrel predicts low response

Anne Bellemain-Appaix1, Gilles Montalescot, Johanne Silvain

  • 1Assistance Publique Hôpitaux de Paris, Institut de Cardiologie, Pitié-Salpêtrière University Hospital, Paris, France.

Journal of the American College of Cardiology
|February 23, 2010
PubMed

Insights

A slow response to clopidogrel loading within the first hour reliably predicts a low overall response and high platelet reactivity at 24 hours. This finding is crucial for managing acute coronary syndromes.

Area of Science:

  • Cardiology
  • Pharmacology
  • Clinical Trials

Background:

  • Fast platelet inhibition is critical for acute coronary syndromes and percutaneous coronary intervention.
  • The link between early clopidogrel response kinetics and final platelet inhibition is not well-established.

Purpose of the Study:

  • To determine if the speed of response to clopidogrel loading predicts the final degree of platelet inhibition.
  • To investigate the association between early clopidogrel response and post-treatment platelet reactivity.

Main Methods:

  • Post hoc analysis of the ALBION study in non-ST-segment elevation acute coronary syndrome patients.
  • Evaluation of adenosine diphosphate maximal platelet aggregation (MPA) and DeltaMPA kinetics within 24 hours after clopidogrel loading (300, 600, or 900 mg).
  • Assessment of inflammatory markers (PAC-1, P-selectin) and vasodilator-stimulated phosphoprotein (VASP) index based on onset of action.

Main Results:

  • Fifty-five percent of patients exhibited a slow response to clopidogrel.
  • Slow responders were more likely to have high post-treatment platelet reactivity (28% vs. 14%).
  • Noncurrent smoking and higher BMI (>25 kg/m²) were linked to slower, lower responses.

Conclusions:

  • Early slow response to clopidogrel (within 1 hour) is a reliable predictor of low response at 24 hours.
  • This early kinetic profile also indicates a higher likelihood of elevated post-treatment platelet reactivity.
  • Findings highlight the importance of monitoring early response to optimize antiplatelet therapy.
Abstract

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