title: High on-clopidogrel treatment platelet reactivity in Thai patients with chronic stable angina scheduled for percutaneous coronary intervention.
abstract: OBJECTIVE
  To determine the prevalence, clinical profile, and risk factors of high on-clopidogrel treatment platelet reactivity in Thai patients with chronic stable angina scheduled for percutaneous coronary intervention.
  
  
  METHODS
  The patients were prospectively recruited from the consecutive patients undergoing coronary angiography and planned for elective percutaneous coronary intervention (PCI). Ten ml of blood samples were cautiously drawn from the antecubital vein of the patients to determine the hemoglobin and platelet count. Platelet aggregation test was performed by light transmittance aggregometry using platelet-rich plasma. Platelets were stimulated with 5 microM adenosine diphosphate (ADP). Platelet aggregation was expressed as the maximal percent change in light transmittance from baseline. High on-clopidogrel treatment platelet reactivity was defined as post treatment maximal platelet aggregation > 46% with 5 micromol/l ADP used as agonist.
  
  
  RESULTS
  The present study consecutively enrolled two hundred four patients diagnosed with chronic stable angina planned for PCI. Seventy-nine patients demonstrated the high on-clopidogrel treatment platelet reactivity (38.7%). Among these patients, 48% were men with a mean age of 66 years. Diabetes mellitus and chronic kidney disease were detected in 34.2%. Original clopidogrel (Plavix) was prescribed in 72% of the patients and 28% received generic clopidogrel (Apolets). The prevalence of high on-clopidogrel treatment platelet reactivity increased in the older patients, patients with CKD and patients receiving angiotensin receptor blockers (ARB). However from multivariate analysis, none of the risk factors, including age, BMl, diabetes mellitus, smoking, CKD, ARB use, and type of clopidogrel (Plavix versus Apolets) had a statistically significant association with the high on-clopidogrel treatment platelet reactivity.
  
  
  CONCLUSIONS
  The prevalence of high on-clopidogrel treatment platelet reactivity in the present study was 38.7%. No significant association was demonstrated between age, BMI, diabetes mellitus, smoking, CKD, ARB use, type of clopidogrel, and high on-clopidogrel treatment platelet reactivity.
authors.affiliation: Division of Cardiology, Department of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand. rewat.pha@mahidol.ac.th
authors.forename: Rewat
authors.initials: R
authors.lastname: Phankingthongkum
authors.forename: Pradit
authors.initials: P
authors.lastname: Panchavinnin
authors.forename: Yingyong
authors.initials: Y
authors.lastname: Chinthammitr
authors.forename: Damras
authors.initials: D
authors.lastname: Tresukosol
authors.forename: Chunhakasem
authors.initials: C
authors.lastname: Chotinaiwattarakul
authors.forename: Wiwun
authors.initials: W
authors.lastname: Tungsubutra
authors.forename: Nattawut
authors.initials: N
authors.lastname: Wongpraparut
authors.forename: Bussakorn
authors.initials: B
authors.lastname: Kitrattana
authors.forename: Piyachat
authors.initials: P
authors.lastname: Leewanun
mesh_terms: D000368:Aged; D060050:Angina, Stable / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology / Q000628:therapy*; D000077144:Clopidogrel; D017023:Coronary Angiography / Q000379:methods; D023903:Coronary Restenosis / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D062645:Percutaneous Coronary Intervention / Q000009:adverse effects / Q000379:methods; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use; D010979:Platelet Function Tests / Q000379:methods*; D015995:Prevalence; D011446:Prospective Studies; D012307:Risk Factors; D013785:Thailand / Q000453:epidemiology; D013988:Ticlopidine / Q000031:analogs & derivatives* / Q000627:therapeutic use
chemical_list: D010975:Platelet Aggregation Inhibitors; D000077144:Clopidogrel; D013988:Ticlopidine