title: Impact of the degree of peri-interventional platelet inhibition after loading with clopidogrel on early clinical outcome of elective coronary stent placement.
abstract: OBJECTIVE
  Our prospective study tested the hypothesis that the 30-day clinical outcome of elective percutaneous catheter intervention (PCI) differs between strata defined by quartiles of platelet aggregation after loading with 600 mg clopidogrel.
  
  
  BACKGROUND
  Platelet responses after loading with clopidogrel are highly variable. The impact of this variability on the peri-interventional risk of patients undergoing PCI has not been investigated prospectively.
  
  
  METHODS
  Our study included 802 consecutive patients undergoing elective coronary stent placement. Before PCI, patients received a loading dose of 600 mg clopidogrel followed by 75 mg daily. Primary end point was the 30-day composite of death, myocardial infarction, and target lesion revascularization (major adverse cardiac events [MACE]). Platelet aggregation was assessed immediately before PCI by optical aggregometry (5 micromol/l adenosine diphosphate).
  
  
  RESULTS
  During 30-day follow-up, 15 patients (1.9%) incurred MACE (3 deaths, 8 myocardial infarctions, 8 target lesion revascularizations). Quartiles of platelet aggregation were <4%, 4% to 14%, 15% to 32%, and >32%. Thirty-day MACE differed significantly (p = 0.034) between quartiles of platelet aggregation. It was 0.5% in the first quartile, 0.5% in the second, 3.1% in the third, and 3.5% in the fourth. Platelet aggregation above the median carried a 6.7-fold risk (95% confidence interval 1.52 to 29.41; p = 0.003) of 30-day MACE. Multivariable logistic regression analysis, including pertinent covariables, confirmed platelet aggregation as a significant independent predictor of 30-day MACE (adjusted odds ratio per 10% increase in platelet aggregation 1.32, 95% confidence interval 1.04 to 1.61; p = 0.026).
  
  
  CONCLUSIONS
  The level of platelet aggregation immediately before elective coronary stenting in patients pre-treated with a high loading dose of clopidogrel is correlated with early outcome after the procedure.
authors.affiliation: Herz-Zentrum Bad Krozingen, Bad Krozingen, Germany.
authors.forename: Willibald
authors.initials: W
authors.lastname: Hochholzer
authors.forename: Dietmar
authors.initials: D
authors.lastname: Trenk
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Bestehorn
authors.forename: Benjamin
authors.initials: B
authors.lastname: Fischer
authors.forename: Christian M
authors.initials: CM
authors.lastname: Valina
authors.forename: Miroslaw
authors.initials: M
authors.lastname: Ferenc
authors.forename: Michael
authors.initials: M
authors.lastname: Gick
authors.forename: Angelika
authors.initials: A
authors.lastname: Caputo
authors.forename: Heinz Joachim
authors.initials: HJ
authors.lastname: Büttner
authors.forename: Franz-Josef
authors.initials: FJ
authors.lastname: Neumann
mesh_terms: D015906:Angioplasty, Balloon, Coronary; D002318:Cardiovascular Diseases / Q000097:blood / Q000188:drug therapy; D000077144:Clopidogrel; D015331:Cohort Studies; D005500:Follow-Up Studies; D006801:Humans; D010974:Platelet Aggregation / Q000187:drug effects / Q000502:physiology; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology / Q000627:therapeutic use*; D011446:Prospective Studies; D015607:Stents; D013988:Ticlopidine / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D016896:Treatment Outcome
chemical_list: D010975:Platelet Aggregation Inhibitors; D000077144:Clopidogrel; D013988:Ticlopidine