title: Clopidogrel resistance is associated with thromboembolic complications in patients undergoing neurovascular stenting.
abstract: OBJECTIVE
  Antiplatelet drug resistance has been associated with thromboembolic complications in patients after coronary stent placement. It has not been well-studied in patients who have neurovascular stent-placement procedures. This study aimed to analyze the relationship between antiplatelet drug resistance and neurovascular stent-placement complications.
  
  
  METHODS
  A prospective data base of all patients treated at our institution was used to identify patients with neurovascular stent-placement procedures. During a 4.5-year period, all patients undergoing neurovascular stent placement were evaluated for aspirin and clopidogrel resistance by using the VerifyNow assay. During an observational phase, all patients received 75 mg of clopidogrel and aspirin (group A). During the intervention phase (group B), patients were given additional clopidogrel on the basis of the clopidogrel resistance assay. We assessed the development of thromboembolic complications within 30 days of the procedure in patients who were resistant-versus-nonresistant to clopidogrel.
  
  
  RESULTS
  Of 96 patients who had neurovascular stent placement, 5.2% were resistant to aspirin and 36.5% were resistant to clopidogrel. Periprocedural thromboembolic complications were seen in 7 patients (7.3%). In a multivariate logistic regression model, clopidogrel resistance, higher diastolic blood pressure, and lack of statin use were significantly associated with periprocedural thromboembolic complication. There was a nonsignificant decrease in thromboembolic complications in patients whose clopidogrel dosage was tailored to the assay.
  
  
  CONCLUSIONS
  In our series, clopidogrel resistance was associated with increased periprocedural thromboembolic complications from neurovascular stent-placement procedures. Targeting the clopidogrel dose to platelet inhibition assays may improve clinical outcomes and requires further study.
authors.affiliation: Center for Endovascular Surgery, Hyman Newman Institute for Neurology and Neurosurgery, Department of Neurology, St. Luke's Roosevelt Hospital Center, New York, NY 10019, USA. jfifi@chpnet.org
authors.forename: J T
authors.initials: JT
authors.lastname: Fifi
authors.forename: C
authors.initials: C
authors.lastname: Brockington
authors.forename: J
authors.initials: J
authors.lastname: Narang
authors.forename: W
authors.initials: W
authors.lastname: Leesch
authors.forename: S L
authors.initials: SL
authors.lastname: Ewing
authors.forename: H
authors.initials: H
authors.lastname: Bennet
authors.forename: A
authors.initials: A
authors.lastname: Berenstein
authors.forename: J
authors.initials: J
authors.lastname: Chong
mesh_terms: D000368:Aged; D001241:Aspirin / Q000008:administration & dosage; D001792:Blood Platelets / Q000187:drug effects; D002536:Cerebral Arteries; D000077144:Clopidogrel; D004305:Dose-Response Relationship, Drug; D004351:Drug Resistance; D057510:Endovascular Procedures / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010974:Platelet Aggregation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage*; D012189:Retrospective Studies; D015607:Stents / Q000009:adverse effects*; D013923:Thromboembolism / Q000188:drug therapy / Q000209:etiology* / Q000517:prevention & control; D013988:Ticlopidine / Q000008:administration & dosage / Q000031:analogs & derivatives*
chemical_list: D010975:Platelet Aggregation Inhibitors; D000077144:Clopidogrel; D013988:Ticlopidine; D001241:Aspirin