title: Chronic kidney disease--is it a true risk factor of reduced clopidogrel efficacy in elderly patients with stable coronary artery disease?
abstract: BACKGROUND
  Chronic kidney disease (CKD) is an established predictor of recurrent ischemic events in patients with coronary artery disease (CAD). This association has been partially ascribed to high post-treatment platelet reactivity (HPPR) according to platelet function testing. However, the influencing factors of HPPR are assay-dependent, and the relevant data of elderly patients with stable CAD are absent.
  
  
  METHODS
  310 elderly patients (>80years of age) with stable CAD taking prolonged maintenance clopidogrel (75mg/day) were studied. Maximal platelet aggregation rate (MPA%) with light transmittance aggregometry and Platelet Reactive Units (PRU) with VerifyNow (VN) P2Y12 system were obtained. Markers of platelet activation, including PAC-1 and CD62P, were also determined.
  
  
  RESULTS
  Patients on different stages of CKD presented similar MPA% and expression of PAC-1 and CD62P. Although severe CKD patients were more likely to present HPPR identified by VNP2Y12 (odds ratio: 1.85, p=0.038), multiple logistic regression diminished this effect (adjusted odds ratio: 1.19, p=0.642), and revealed anemia as a possible predictor of HPPR (adjusted odds ratio: 5.92, p=0.001). However, in a parallel way, hemoglobin correlated with baseline PRU values as well as with post-treatment values (r=-0.624 and r=-0.463, respectively, p<0.001). Association between hemoglobin and PRU inhibition rate was not found. Moreover, hemoglobin exerted no influence on MPA% at all.
  
  
  CONCLUSIONS
  CKD is not necessarily associated with reduced antiplatelet effects of clopidogrel in elderly patients with stable CAD taking prolonged maintenance clopidogrel, and the seemingly influence of CKD on HPPR assessed by VNP2Y12 assay may be due to the artifactual effect of hemoglobin on VNP2Y12.
authors: Second Geriatric Cardiology Division, Chinese PLA General Hospital, Beijing, China.
authors: Wen-Xiu
authors: WX
authors: Leng
authors: Jun-Wei
authors: JW
authors: Ren
authors: Jian
authors: J
authors: Cao
authors: Yu-Long
authors: YL
authors: Cong
authors: Hua
authors: H
authors: Cui
authors: Guo-Liang
authors: GL
authors: Hu
authors: Qing-Qing
authors: QQ
authors: Hu
authors: Hui
authors: H
authors: Niu
authors: Li
authors: L
authors: Fan
mesh_terms: D000369:Aged, 80 and over; D001792:Blood Platelets / Q000187:drug effects; D000077144:Clopidogrel; D003324:Coronary Artery Disease / Q000150:complications / Q000175:diagnosis* / Q000188:drug therapy*; D003404:Creatinine / Q000378:metabolism; D005260:Female; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D008297:Male; D016017:Odds Ratio; D019007:P-Selectin / Q000378:metabolism; D015539:Platelet Activation; D010974:Platelet Aggregation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use*; D058925:Receptors, Purinergic P2Y12 / Q000378:metabolism; D012044:Regression Analysis; D051436:Renal Insufficiency, Chronic / Q000150:complications / Q000175:diagnosis*; D012307:Risk Factors; D013988:Ticlopidine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D016896:Treatment Outcome
chemical_list: D006454:Hemoglobins; D019007:P-Selectin; C548576:P2RY12 protein, human; D010975:Platelet Aggregation Inhibitors; D058925:Receptors, Purinergic P2Y12; D000077144:Clopidogrel; D003404:Creatinine; D013988:Ticlopidine