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Intra-individual variability in clopidogrel responsiveness in coronary artery disease patients under long term

Sébastien Arméro1, Laurence Camoin Jau, Omar Omar Aït Mokhtar

  • 1Pôle de Cardiologie, Service de Cardiologie Interventionnelle, Hôpital Universitaire Nord, AP-HM, Faculté de Médecine, Université Aix-Marseille II, France.

Platelets
|July 31, 2010
PubMed

Insights

Clopidogrel responsiveness shows significant intra-individual variability, meaning a patient's response can change over time. This decreased responsiveness, even with long-term therapy, may increase the risk of thrombotic events after PCI.

Area of Science:

  • Cardiology
  • Pharmacology
  • Thrombosis Research

Background:

  • Clopidogrel responsiveness (CR) after percutaneous coronary interventions (PCI) is crucial for predicting thrombotic events.
  • Significant inter-individual variability in CR exists, prompting investigation into intra-individual variability.

Purpose of the Study:

  • To investigate the intra-individual variability in clopidogrel responsiveness (CR) in patients undergoing drug-eluting stent PCI.
  • To assess the impact of long-term clopidogrel therapy and re-admission on CR.

Main Methods:

  • Prospective monocentre study of 201 patients on long-term aspirin and clopidogrel post-PCI.
  • Platelet reactivity (PR) assessed using the vasodilator phosphoprotein (VASP) index after a 600 mg clopidogrel loading dose (LD) on each admission.
  • Intra-individual variability analyzed by comparing VASP index between first admission (VASP 1) and re-admission (VASP 2), calculating DeltaVASP (VASP 2 – VASP 1).

Main Results:

  • Clopidogrel response showed poor intra-individual correlation (kappa = 0.33, p < 0.001).
  • 35.3% of patients exhibited decreased platelet inhibition upon re-admission despite chronic therapy and a 600 mg reload.
  • Insulin-treated diabetes was associated with decreased CR over time (p = 0.03).

Conclusions:

  • Significant intra-individual variability in clopidogrel responsiveness exists, in addition to inter-individual variability.
  • Decreased clopidogrel responsiveness during long-term therapy may serve as a trigger for recurrent thrombotic events post-PCI.

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