title: Platelet function testing to predict hyporesponsiveness to clopidogrel in patients with chest pain seen in the emergency department.
abstract: BACKGROUND
  A dual antiplatelet regimen has been shown to reduce the risk of major adverse cardiovascular events after percutaneous coronary intervention. However, there is little information available on inhibition of platelet aggregation in patients with a prior coronary stent presenting with chest pain. This study evaluated the prevalence of hyporesponsiveness to clopidogrel and factors associated with this in patients presenting to our emergency department with chest pain who had previously undergone coronary stent placement and were prescribed dual antiplatelet therapy.
  
  
  METHODS
  Responsiveness to clopidogrel was evaluated in a cohort of 533 consecutive stented patients presenting to the emergency department with chest pain. P2Y12 reaction units (PRU) and percent P2Y12 inhibition with clopidogrel were measured in all patients. Of 533 patients, 221 (41.6%) had PRU ≥ 230. A multivariate logistic regression model was used to determine the relationship between hyporesponsiveness to clopidogrel (defined as PRU ≥ 230) and several potential risk factors, ie, gender, age, race, type 1 or type 2 diabetes, hypertension, smoking, chronic renal failure, and obesity.
  
  
  RESULTS
  There was a greater risk of hyporesponsiveness in African Americans than in non-African American patients (adjusted odds ratio [OR] = 2.165), in patients with type 2 diabetes than in those without (adjusted OR = 2.109), and in women than in men (adjusted OR = 1.813), as well as a greater risk of hyporesponsiveness with increasing age (adjusted OR = 1.167 per decade).
  
  
  CONCLUSIONS
  There was a high prevalence of hyporesponsiveness to clopidogrel in patients presenting with chest pain and a prior coronary stent. Non-insulin-dependent diabetes mellitus and African American race were the strongest predictors of hyporesponsiveness to clopidogrel, followed by gender and age.
authors: Division of Cardiovascular Medicine, University of Arkansas for Medical Sciences, Little Rock, AR, USA. rsharma@uams.edu
authors: Rakesh K
authors: RK
authors: Sharma
authors: Stephen W
authors: SW
authors: Erickson
authors: Rohit
authors: R
authors: Sharma
authors: Donald J
authors: DJ
authors: Voelker
authors: Hanumanth K
authors: HK
authors: Reddy
authors: Harvinder
authors: H
authors: Dod
authors: James D
authors: JD
authors: Marsh
mesh_terms: D001741:Black or African American; D000367:Age Factors; D000368:Aged; D001792:Blood Platelets / Q000187:drug effects* / Q000378:metabolism; D002637:Chest Pain / Q000097:blood / Q000208:ethnology / Q000209:etiology*; D000077144:Clopidogrel; D003924:Diabetes Mellitus, Type 2 / Q000150:complications; D004351:Drug Resistance; D004359:Drug Therapy, Combination; D004636:Emergency Service, Hospital; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D062645:Percutaneous Coronary Intervention / Q000009:adverse effects / Q000295:instrumentation; D010975:Platelet Aggregation Inhibitors / Q000009:adverse effects / Q000627:therapeutic use*; D010979:Platelet Function Tests; D011237:Predictive Value of Tests; D011446:Prospective Studies; D058921:Purinergic P2Y Receptor Antagonists / Q000009:adverse effects / Q000627:therapeutic use*; D058925:Receptors, Purinergic P2Y12 / Q000097:blood / Q000187:drug effects; D018570:Risk Assessment; D012307:Risk Factors; D012737:Sex Factors; D015607:Stents; D013988:Ticlopidine / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000627:therapeutic use; D016896:Treatment Outcome
chemical_list: C548576:P2RY12 protein, human; D010975:Platelet Aggregation Inhibitors; D058921:Purinergic P2Y Receptor Antagonists; D058925:Receptors, Purinergic P2Y12; D000077144:Clopidogrel; D013988:Ticlopidine
keywords: chest pain; clopidogrel; emergency department; platelet function testing
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