A randomised study comparing the antiplatelet and antiinflammatory effect of clopidogrel 150 mg/day versus 75 mg/day in patients with ST-segment elevation acute myocardial infarction and poor responsiveness to clopidogrel: results from the DOUBLE study.
BACKGROUND
The antiplatelet effect of standard or increased clopidogrel doses in patients with ST- segment elevation acute myocardial infarction (STEMI) has never been studied. In this study we compared the antiplatelet effect of a 75 mg daily maintenance dose of clopidogrel with 150 mg in patients with STEMI undergoing primary percutaneous coronary intervention (PCI).


METHODS
Fifty-four patients with STEMI undergoing PCI were randomly allocated to receive either 75 mg/day clopidogrel (group 1) or 150 mg/day (group 2) for 1 month. Platelet function, measured by 5 different assays, was determined at 3 time points: 38+/-8 hours after the procedure, 1 week and 1 month after randomization.


RESULTS
In group 1, mean +/- SD platelet reactivity index (PRI) measured with the VASP assay was 57.7+/-15.7% and 46.9+/-15.7% at 1 week and 1 month, respectively, compared to 38.8+/-15.7% and 34.9+/-12.6% in group 2 (p=0.0001). Same results were observed for light transmittance aggregometry, whole blood aggregometry and VerifyNow, but not for thromboelastometry. In contrast to what may be expected, the 75 mg daily maintenance dose took longer than 1-week to provide the full clopidogrel antiplatelet effect. Furthermore, patients in group 2 had a nearly 50% reduction in C-reactive protein levels both at 1 week and 1 month.


CONCLUSIONS
In patients with STEMI and poor responsiveness to clopidogrel a 150 mg daily maintenance dose of clopidogrel is associated with a significant reduction of platelet aggregation and a trend towards reduced inflammation.
Palmerini
Tullio
T
Istituto di Cardiologia, Policlinico S. Orsola, Università di Bologna, Italy. tulliopalmerini@hotmail.com
Barozzi
Chiara
C
Tomasi
Luciana
L
Sangiorgi
Diego
D
Marzocchi
Antonio
A
De Servi
Stefano
S
Ortolani
Paolo
P
Reggiani
Letizia Bacchi
LB
Alessi
Laura
L
Lauria
Giulia
G
Bassi
Mirna
M
Branzi
Angelo
A
D056988:Anterior Wall Myocardial Infarction; D000893:Anti-Inflammatory Agents / Q000494:pharmacology / Q000627:therapeutic use*; D002097:C-Reactive Protein / Q000494:pharmacology / Q000627:therapeutic use; D015815:Cell Adhesion Molecules / Q000378:metabolism; D000077144:Clopidogrel; D006801:Humans; D008840:Microfilament Proteins / Q000378:metabolism; D009203:Myocardial Infarction / Q000097:blood / Q000188:drug therapy*; D010750:Phosphoproteins / Q000378:metabolism; D010974:Platelet Aggregation / Q000187:drug effects*; D013988:Ticlopidine / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D000098662:Vasodilator-Stimulated Phosphoprotein
D000893:Anti-Inflammatory Agents; D015815:Cell Adhesion Molecules; D008840:Microfilament Proteins; D010750:Phosphoproteins; D000098662:Vasodilator-Stimulated Phosphoprotein; D002097:C-Reactive Protein; D000077144:Clopidogrel; D013988:Ticlopidine