Clopidogrel loading with eptifibatide to arrest the reactivity of platelets: results of the Clopidogrel Loading With Eptifibatide to Arrest the Reactivity of Platelets (CLEAR PLATELETS) study.
BACKGROUND
Pretreatment is not the most common strategy practiced for clopidogrel administration in elective coronary stenting. Moreover, limited information is available on the antiplatelet pharmacodynamics of a 300-mg versus a 600-mg clopidogrel loading dose, and the comparative effect of eptifibatide with these regimens is unknown.


RESULTS
Patients undergoing elective stenting (n=120) were enrolled in a 2x2 factorial study (300 mg clopidogrel with or without eptifibatide; 600 mg clopidogrel with or without eptifibatide) (Clopidogrel Loading With Eptifibatide to Arrest the Reactivity of Platelets [CLEAR PLATELETS] Study). Clopidogrel was administered immediately after stenting. Aggregometry and flow cytometry were used to assess platelet reactivity. Eptifibatide added a > or =2-fold increase in platelet inhibition to 600 mg clopidogrel alone at 3, 8, and 18 to 24 hours after stenting as measured by 5 micromol/L ADP-induced aggregation (P<0.001). Without eptifibatide, 600 mg clopidogrel produced better inhibition than 300 mg clopidogrel at all time points (P<0.001). Glycoprotein IIb/IIIa (GPIIb/IIIa) blockade was associated with lower cardiac marker release. Active GPIIb/IIIa expression was inhibited most in the groups treated with eptifibatide (P<0.05).


CONCLUSIONS
In elective stenting without clopidogrel pretreatment, use of a GPIIb/IIIa inhibitor produces superior platelet inhibition and lower myocardial necrosis compared with high-dose (600 mg) or standard-dose (300 mg) clopidogrel loading alone. In the absence of a GPIIb/IIIa inhibitor, 600 mg clopidogrel provides better platelet inhibition than the standard 300-mg dose. These results require confirmation in a large-scale clinical trial.
Gurbel
Paul A
PA
Sinai Center for Thrombosis Research, Hoffberger Bldg, Suite 56, 2401 W Belvedere Ave, Baltimore, MD 21215, USA. pgurbel@lifebridgehealth.org
Bliden
Kevin P
KP
Zaman
Kazi A
KA
Yoho
Jason A
JA
Hayes
Kevin M
KM
Tantry
Udaya S
US
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000787:Angina Pectoris / Q000209:etiology; D015906:Angioplasty, Balloon, Coronary; D002317:Cardiovascular Agents / Q000627:therapeutic use; D000077144:Clopidogrel; D023921:Coronary Stenosis / Q000097:blood / Q000150:complications / Q000503:physiopathology / Q000628:therapy; D003328:Coronary Thrombosis / Q000517:prevention & control; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D004359:Drug Therapy, Combination; D000077542:Eptifibatide; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000209:etiology; D009206:Myocardium / Q000473:pathology; D009336:Necrosis; D010455:Peptides / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D010974:Platelet Aggregation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000037:antagonists & inhibitors; D011292:Premedication; D012307:Risk Factors; D015607:Stents; D013988:Ticlopidine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use
D002317:Cardiovascular Agents; D010455:Peptides; D010975:Platelet Aggregation Inhibitors; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D000077144:Clopidogrel; D000077542:Eptifibatide; D013988:Ticlopidine