title: Impact of a 600-mg loading dose of clopidogrel on 30-day outcome in unselected patients undergoing percutaneous coronary intervention.
abstract: On the basis of biologic studies of platelet reactivity, the recent American College of Cardiology and American Heart Association guidelines recommend a 600-mg loading dose (LD) of clopidogrel in patients who undergo percutaneous coronary intervention (PCI). There is, however, a lack of studies addressing the clinical impact of such a clopidogrel LD. The aim of this study was to compare the clinical efficacy and safety of a 600-mg LD of clopidogrel with that of a 300-mg LD in an unselected cohort of patients who underwent PCI. A cohort of 4,105 unselected patients who underwent PCI were included in the study and divided according to the LD used: the high-LD group (600 mg) included 3,146 patients, and the low-LD group (300 mg) included 959. The primary end point was the rate of major adverse cardiovascular events (MACEs) at 1 month. Patients in the low-LD group more often had diabetes mellitus and histories of myocardial infarction (36.8% vs 31.9%, p = 0.01). Left ventricular ejection fractions were similar (0.49 +/- 0.14 vs 0.48 +/- 0.14, p = 0.25). Angiographic and procedural characteristics were identical between the 2 groups. Patients in the high-LD group had fewer MACEs after 1 month (2.9% vs 5.2%, p <0.001). In multivariate analysis, an LD of 600 mg was significantly associated with MACEs at 1-month follow-up, with an odds ratio of 0.62 (95% confidence interval 0.41 to 0.95, p = 0.03). In conclusion, a 600-mg LD was associated with a significant decrease in the rate of post-PCI MACEs at 1 month, without any in-hospital increase in bleeding complications. The results of this study therefore support the current guidelines of a 600-mg LD of clopidogrel in patients who undergo PCI.
authors.affiliation: Department of Internal Medicine, Division of Cardiology, Washington Hospital Center, Washington, DC, USA.
authors.forename: Laurent
authors.initials: L
authors.lastname: Bonello
authors.forename: Gilles
authors.initials: G
authors.lastname: Lemesle
authors.forename: Axel
authors.initials: A
authors.lastname: De Labriolle
authors.forename: Probal
authors.initials: P
authors.lastname: Roy
authors.forename: Daniel H
authors.initials: DH
authors.lastname: Steinberg
authors.forename: Tina L
authors.initials: TL
authors.lastname: Pinto Slottow
authors.forename: Zhenyi
authors.initials: Z
authors.lastname: Xue
authors.forename: Rebecca
authors.initials: R
authors.lastname: Torguson
authors.forename: William O
authors.initials: WO
authors.lastname: Suddath
authors.forename: Lowell F
authors.initials: LF
authors.lastname: Satler
authors.forename: Kenneth M
authors.initials: KM
authors.lastname: Kent
authors.forename: Augusto D
authors.initials: AD
authors.lastname: Pichard
authors.forename: Joseph
authors.initials: J
authors.lastname: Lindsay
authors.forename: Ron
authors.initials: R
authors.lastname: Waksman
mesh_terms: D000368:Aged; D015906:Angioplasty, Balloon, Coronary / Q000009:adverse effects; D002318:Cardiovascular Diseases / Q000209:etiology / Q000517:prevention & control*; D000077144:Clopidogrel; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage*; D012189:Retrospective Studies; D013988:Ticlopidine / Q000008:administration & dosage / Q000031:analogs & derivatives*; D013997:Time Factors
chemical_list: D010975:Platelet Aggregation Inhibitors; D000077144:Clopidogrel; D013988:Ticlopidine