Biological efficacy of a 600 mg loading dose of clopidogrel in ST-elevation myocardial infarction

Journal: Thrombosis and Haemostasis
ISSN: 0340-6245
Issue: 2012: 108/1 (July) pp. 1-200
Pages: 101-106

Biological efficacy of a 600 mg loading dose of clopidogrel in ST-elevation myocardial infarction

L. Bonello (1, 2), J. Berbis (3, 4), M. Laine (1), S. Armero (1), J. Bessereau (5), L. Jacquin (5), C. Bonello (6), E. Camillieri (7), P. Barragan (8), F. Dignat-George (2, 9), F. Paganelli (1), L. Camoin-Jau (9, 10)

(1) Département de Cardiologie, Hôpital Universitaire Nord, Aix-Marseille University, Marseille, France; (2) INSERM UMRS 608, Faculté de Pharmacie, Marseille, France; (3) Faculté de Médecine, Aix-Marseille University, Marseille, France; (4) Research Unit EA 3279 and Department of Public Health, Marseille, France; (5) Pôle RUSH, Hôpital Timone, Marseille, France; (6) Service de Santé Publique et Information Médicale, Hôpital Universitaire Nord, Faculté de Médecine, Marseille, France; (7) Service de Cardiologie, Hôpital de Martigues, Martigues, France; (8) Service de Cardiologie, Clinique les Fleurs, Ollioules, France; (9) Laboratoire d’Hématologie, Hôpital de la Conception, Marseille, France; (10) URMITE UMR 6236, CNRS-IRD, Faculté de Médecine et de Pharmacie, Marseille, France


Acute coronary syndrome, percutaneous coronary intervention, High on-treatment platelet reactivity, VASP index


Optimal platelet reactivity (PR) inhibition is critical to prevent thrombotic events in primary percutaneous coronary intervention (PCI). We aimed to determine the relationship between high on-treatment platelet reactivity (HTPR) and ST-elevation myocardial infarction (STEMI) following a 600 mg loading dose (LD) of clopidogrel. We performed a prospective monocentre study enrolling patients on clopidogrel undergoing PCI. The VASP index was used to assess PR inhibition after clopidogrel LD. HTPR was defined according to the consensus as a VASP index ≥50%. The present study included 833 patients undergoing PCI. Most patients had PCI for an acute coronary syndrome (58.7%). The mean VASP index was 50 ± 23% with a large inter-individual variability (range: 1–94%). Patients with a VASP index ≥50% were significantly older (p= 0.03), with a higher body mass index (BMI) (p<0.001), more often diabetic (p=0.03), taking omeprazole (p=0.03), admitted for an acute coronary syndrome (ACS) and with a high fibrinogen level compared to good responders (VASP <50%). In multivariate analysis BMI, omeprazole use, ACS and high fibrinogen level (p<0.001) remained significantly associated with HTPR. Of importance, in this analysis STEMI was independently associated with HTPR when compared with the other forms of ACS (NSTEMI and unstable angina) with an odd ratio of 2.14 (95% CI: 1.3 –3.5; p=0.003). In conclusion, STEMI is associated with high on-treatment platelet reactivity following 600 mg of clopidogrel. The present results suggest that 600 mg of clopidogrel may not be able to achieve an optimal PR inhibition in STEMI patients undergoing PCI and more potent drugs may be preferred.

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