title: High on-treatment platelet reactivity predicts cardiac events in patients with drug-eluting stents.
abstract: BACKGROUND
  The role of platelet reactivity (PR) tests in the prediction of long-term events in Latin-American patients treated with drug-eluting stents (DES) has not been established.
  
  
  OBJECTIVE
  To assess the role of PR tests in the prediction of events after DES implantation.
  
  
  METHODS
  From May 2006 through January 2008, 209 Brazilian patients who underwent elective treatment with DES were included. PR was assessed 12 to 18h after the procedure by light transmittance aggregometry with 5µM of ADP. Patients were prospectively followed for up to 4.8 years. Seventeen (8%) individuals were lost to follow-up and the final cohort comprised 192 patients. Receiver operating curve (ROC) was used to determine the best 5µM of ADP cutoff to predict events. The primary endpoint was a combination of cardiovascular death, acute myocardial infarction, definite stent thrombosis, and target-artery revascularization. Cox proportional hazard models were used to determine the variables independently associated with the time to the first event.
  
  
  RESULTS
  The best ADP 5µM cutoff was 33%. One hundred and seven (55.7%) patients had ADP 5µM >33%. Event-free survival rate at 1,800 days was 55% vs. 70% for individuals with ADP5 above and below such cutoff, respectively (p=0.001). Independent predictors of time to first event were current smoking (HR 3.49; 95% CI 1.76-6.9; p=0.0003), ADP 5µM >33% (HR 1.95; 95% CI 1.09-3.51; p=0.025) and age (HR 1.03; 95% CI 1.0-1.06; p=0.041).
  
  
  CONCLUSIONS
  In this study, 55.7% of the patients had high on-treatment platelet reactivity. ADP 5µM >33% was an independent predictor of long-term events.
authors.affiliation: Programa de Pós-Graduação em Ciências Cardiovasculares, Universidade Federal Fluminense, Niterói, RJ. hvillacorta@cardiol.br
authors.forename: Aline Sterque
authors.initials: AS
authors.lastname: Villacorta
authors.forename: Humberto
authors.initials: H
authors.lastname: Villacorta Junior
authors.forename: Marcos J S
authors.initials: MJ
authors.lastname: Batista
authors.forename: Renato Villela
authors.initials: RV
authors.lastname: Gomes
authors.forename: Luiz Augusto
authors.initials: LA
authors.lastname: Macedo
authors.forename: Bruno
authors.initials: B
authors.lastname: Helmuth
authors.forename: Evandro Tinoco
authors.initials: ET
authors.lastname: Mesquita
mesh_terms: D000368:Aged; D001938:Brazil / Q000453:epidemiology; D002318:Cardiovascular Diseases / Q000453:epidemiology / Q000517:prevention & control*; D000077144:Clopidogrel; D054855:Drug-Eluting Stents / Q000009:adverse effects*; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D008297:Male; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000009:adverse effects*; D010979:Platelet Function Tests / Q000379:methods / Q000592:standards*; D012015:Reference Standards; D012307:Risk Factors; D013988:Ticlopidine / Q000009:adverse effects / Q000031:analogs & derivatives*
chemical_list: D010975:Platelet Aggregation Inhibitors; D000077144:Clopidogrel; D013988:Ticlopidine