Impact of initial clinical presentation on clopidogrel low response.
BACKGROUND
Large interindividual variability exists in clopidogrel response. Clopidogrel low response correlates with poor prognosis after percutaneous coronary intervention. Some authors also suggest intraindividual variability over time.


OBJECTIVE
To assess the impact of initial clinical presentation on clopidogrel low response.


METHODS
In this prospective study, clopidogrel response was assessed in 100 patients. Fifty patients presenting with acute coronary syndromes (ACS group) were compared with 50 patients with stable coronary artery disease matched 1:1 for age, sex, body mass index and diabetes (stable group). All patients were tested 18-24h after a 600 mg loading dose of clopidogrel using the VerifyNow-P2Y12 test (results expressed as platelet reaction units [PRUs]). Patients under chronic clopidogrel therapy or treated with glycoprotein IIb/IIIa inhibitors, bivalirudin or thrombolytics were excluded.


RESULTS
Mean age was 61 ± 12 years in each group; 28% of patients in each group were diabetic; mean body mass index was 27.6 ± 5.6 kg/m(2) in the ACS group and 27.9 ± 5.9 kg/m(2) in the stable group (p=0.80). Mean PRU values were 197 ± 81 in the ACS group and 159 ± 94 in the stable group (p=0.03). By multivariable analysis, the ACS group was significantly associated with a higher PRU value (p=0.02). There were significantly more clopidogrel low responders (PRU value>230) in the ACS group (38% vs. 18%; p=0.04).


CONCLUSIONS
Our study confirms that initial clinical presentation, especially ACS, is a strong predictor of clopidogrel low response; this suggests that the evolution of coronary artery disease for one patient influences the clopidogrel response over time. These results are in accordance with recent trials showing a benefit for more aggressive antiplatelet therapy in ACS patients.
Unité des soins intensifs de cardiologie, centre hémodynamique, clinique de cardiologie, hôpital cardiologique, centre hospitalier régional et universitaire de Lille, boulevard du Pr-Jules-Leclercq, 59037 Lille cedex, France.
Jean-Baptiste
JB
Landel
Anne
A
Bauters
Cédric
C
Delhaye
Laurent
L
Bonello
Arnaud
A
Sudre
Sophie
S
Susen
Christophe
C
Bauters
Jean-Marc
JM
Lablanche
Gilles
G
Lemesle
D054058:Acute Coronary Syndrome / Q000175:diagnosis / Q000628:therapy*; D000368:Aged; D001792:Blood Platelets / Q000187:drug effects* / Q000378:metabolism; D016009:Chi-Square Distribution; D000077144:Clopidogrel; D003324:Coronary Artery Disease / Q000175:diagnosis / Q000628:therapy*; D005260:Female; D006801:Humans; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D062645:Percutaneous Coronary Intervention / Q000009:adverse effects; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use*; D010979:Platelet Function Tests; D011237:Predictive Value of Tests; D011446:Prospective Studies; D058921:Purinergic P2Y Receptor Antagonists / Q000627:therapeutic use*; D058925:Receptors, Purinergic P2Y12 / Q000097:blood / Q000187:drug effects*; D012307:Risk Factors; D013988:Ticlopidine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D013997:Time Factors; D016896:Treatment Outcome
C548576:P2RY12 protein, human; D010975:Platelet Aggregation Inhibitors; D058921:Purinergic P2Y Receptor Antagonists; D058925:Receptors, Purinergic P2Y12; D000077144:Clopidogrel; D013988:Ticlopidine
ACS; ADP; Acute coronary syndromes; Angioplastie coronaire percutanée; Antiagrégant plaquettaire; Antiplatelet therapy; BMI; Clopidogrel response; PCI; PRU; Percutaneous coronary intervention; Réponse au clopidogrel; Syndrome coronaire aigu; VerifyNow-P2Y12; acute coronary syndromes; adenosine diphosphate; body mass index; percutaneous coronary intervention; platelet reaction unit