title: Antiplatelet effects of clopidogrel dose adjustment (75 mg/d vs 150 mg/d) after carotid stenting.
abstract: OBJECTIVE
  Clopidogrel plays a central role in the treatment of patients undergoing carotid artery stenting (CAS). The objective was to evaluate the effect of clopidogrel (75 mg/d) on platelet reactivity in responders and nonresponders and the antiplatelet effect of different doses of clopidogrel in patients with high on-treatment reactivity (OTR) after CAS.
  
  
  METHODS
  Patients with high OTR (defined by VerifyNow (Accumetrics, San Diego, Calif) assay as ≥230 P2Y12 reaction units [PRU]) were randomly assigned in a 1:1 ratio to group 1 (standard-dose clopidogrel therapy: 75 mg/d for 30 days) or group 2 (high-dose clopidogrel: 150 mg/d for 30 days).
  
  
  RESULTS
  The study enrolled 214 patients. Of these, 115 (53.7%) were clopidogrel responders (group 0), and 99 (46.3%) had high OTR (clopidogrel nonresponders); of which, 50 were randomly assigned to group 1 and 49 to group 2. At baseline, the PRU value did not differ between group 1 (288.50 ± 46) and group 2 (295.45 ± 47.2; P = .308). Patients displayed reduced mean platelet reactivity levels at 30 days in group 1 (238.96 ± 72.25; P < .001) and group 2 (201.85 ± 77.8; P < .001). Although high-dose clopidogrel resulted in more intense platelet function inhibition, the differences between median 30-day PRU values (P = .483) and the percentage change of PRU (P = .442) for groups 1 and 2 were not significant. The incidences of transient ischemic attack, stroke, or death at up to 30 days after CAS in the high-OTR patients were similar between groups 1 and 2 (P = .481).
  
  
  CONCLUSIONS
  Patients with high OTR undergoing CAS treated with standard-dose and double-dose clopidogrel had significantly reduced platelet reactivity after 30 days. The double dose did not result in statistically significantly greater reductions in reactivity compared with the standard dose.
authors.affiliation: Department of Radiology, Interventional Neuroradiology, Virgen del Rocio University Hospital, Seville, Spain. Electronic address: ggjandro@gmail.com.
authors.forename: Alejandro
authors.initials: A
authors.lastname: González
authors.affiliation: Department of Neurology, Virgen del Rocio University Hospital, Seville, Spain.
authors.forename: Francisco
authors.initials: F
authors.lastname: Moniche
authors.affiliation: Department of Research Unit, Virgen del Rocio University Hospital, Seville, Spain.
authors.forename: Aurelio
authors.initials: A
authors.lastname: Cayuela
authors.affiliation: Department of Neurology, Virgen del Rocio University Hospital, Seville, Spain.
authors.forename: Jose Ramón
authors.initials: JR
authors.lastname: Gonzalez-Marcos
authors.affiliation: Department of Radiology, Interventional Neuroradiology, Virgen del Rocio University Hospital, Seville, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Mayol
authors.affiliation: Neurovascular Research Group, Stroke Programme, IBIS-HVR, Seville, Spain.
authors.forename: Joan
authors.initials: J
authors.lastname: Montaner
mesh_terms: D000368:Aged; D017130:Angioplasty / Q000009:adverse effects / Q000295:instrumentation* / Q000401:mortality; D001792:Blood Platelets / Q000187:drug effects* / Q000378:metabolism; D002340:Carotid Artery Diseases / Q000150:complications / Q000175:diagnosis / Q000401:mortality / Q000628:therapy*; D000077144:Clopidogrel; D005260:Female; D006801:Humans; D002546:Ischemic Attack, Transient / Q000209:etiology; D008297:Male; D008875:Middle Aged; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage* / Q000009:adverse effects; D010979:Platelet Function Tests; D011446:Prospective Studies; D058921:Purinergic P2Y Receptor Antagonists / Q000008:administration & dosage* / Q000009:adverse effects; D058925:Receptors, Purinergic P2Y12 / Q000187:drug effects* / Q000378:metabolism; D013030:Spain; D015607:Stents; D020521:Stroke / Q000209:etiology; D013988:Ticlopidine / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives*; D013997:Time Factors; 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