title: Clopidogrel resistance in Japanese patients scheduled for percutaneous coronary intervention.
abstract: BACKGROUND
  Dual antiplatelet therapy with acetylsalicylic acid (ASA) and a P2Y(12) ADP-receptor blocker is standard for prevention of coronary stent thrombosis. Clopidogrel, a 2(nd)-generation P2Y(12) blocker, has recently become available in Japan and this study aimed to evaluate its antiplatelet effects in Japanese patients.
  
  
  RESULTS
  Thirty Japanese patients scheduled for elective coronary stent implantation were enrolled. Under low-dose ASA therapy, 300 mg clopidogrel was loaded on the 1(st) day and a daily 75-mg dose was administered on the following days. Assessed by optical aggregometer, rapid inhibition occurred at 4 h, when the inhibition of platelet aggregation rate (IPA) was 16.4+/-12.8% using 5 mumol/L ADP as the stimulus. The antiplatelet efficacy of clopidogrel was reasonably constant in each patient throughout the study period, although there was a broad inter-individual variation. At 48 h after clopidogrel loading, the ratios of responders (IPA > or =30%), hypo-responders (10%< or =IPA<30%), and non-responders (IPA <10%) were 36%, 50%, and 14%, respectively.
  
  
  CONCLUSIONS
  The antiplatelet effectiveness of clopidogrel appeared individual-specific with wide inter-individual variation. The rate of clopidogrel non-responders was 14% among the examined Japanese patients.
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Kozo
authors.initials: K
authors.lastname: Hoshino
authors.forename: Hisanori
authors.initials: H
authors.lastname: Horiuchi
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Tada
authors.forename: Junichi
authors.initials: J
authors.lastname: Tazaki
authors.forename: Eiichiro
authors.initials: E
authors.lastname: Nishi
authors.forename: Mitsunori
authors.initials: M
authors.lastname: Kawato
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Ikeda
authors.forename: Hiromi
authors.initials: H
authors.lastname: Yamamoto
authors.forename: Masaharu
authors.initials: M
authors.lastname: Akao
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Furukawa
authors.forename: Satoshi
authors.initials: S
authors.lastname: Shizuta
authors.forename: Masanao
authors.initials: M
authors.lastname: Toma
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Tamura
authors.forename: Naritatsu
authors.initials: N
authors.lastname: Saito
authors.forename: Takahiro
authors.initials: T
authors.lastname: Doi
authors.forename: Neiko
authors.initials: N
authors.lastname: Ozasa
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Jinnai
authors.forename: Kanako
authors.initials: K
authors.lastname: Takahashi
authors.forename: Haruyo
authors.initials: H
authors.lastname: Watanabe
authors.forename: Yuka
authors.initials: Y
authors.lastname: Yoshikawa
authors.forename: Naoko
authors.initials: N
authors.lastname: Nishimoto
authors.forename: Chiho
authors.initials: C
authors.lastname: Ouchi
authors.forename: Takeshi
authors.initials: T
authors.lastname: Morimoto
authors.forename: Toru
authors.initials: T
authors.lastname: Kita
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kimura
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015906:Angioplasty, Balloon, Coronary; D015815:Cell Adhesion Molecules / Q000378:metabolism; D000077144:Clopidogrel; D023921:Coronary Stenosis / Q000208:ethnology* / Q000517:prevention & control*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008297:Male; D008840:Microfilament Proteins / Q000378:metabolism; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000628:therapy*; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D010974:Platelet Aggregation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology / Q000627:therapeutic use*; D015607:Stents; D013988:Ticlopidine / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D016896:Treatment Outcome; D000098662:Vasodilator-Stimulated Phosphoprotein
chemical_list: D015815:Cell Adhesion Molecules; D008840:Microfilament Proteins; D010750:Phosphoproteins; D010975:Platelet Aggregation Inhibitors; D000098662:Vasodilator-Stimulated Phosphoprotein; D000077144:Clopidogrel; D013988:Ticlopidine