title: Residual platelet reactivity after aspirin and clopidogrel treatment predicts 2-year major cardiovascular events in patients undergoing percutaneous coronary intervention.
abstract: BACKGROUND
  Studies on the prognostic significance of residual platelet reactivity despite the use of dual anti-platelet agents are limited and seldom extend beyond 1year.
  
  
  METHODS
  This study enrolled 144 patients treated with standard-dose aspirin and clopidogrel and undergoing percutaneous coronary intervention (PCI). Platelet reactivity was measured by the Platelet Function Analyzer-100 (PFA-100) just before PCI and presented as collagen/epinephrine closure time (CEPI-CT) and collagen/adenosine diphosphate closure time (CADP-CT). Primary endpoint included cardiovascular death, myocardial infarction, and stroke. Secondary endpoint was the primary endpoint plus hospitalization due to unstable angina or urgent target vessel revascularization.
  
  
  RESULTS
  During the 24-month follow-up, 14 patients (9.7%) developed the primary endpoint events and 33 had the secondary endpoints. After controlling possible confounding factors, both CEPI-CT <193s and CADP-CT <95s were independently predictive of the primary endpoint (hazard ratio=3.5; 95% confidence interval: 1.04-11.7; p=0.044 and 5.3; 1.4-20.1; p=0.015, respectively). Only CADP-CT <95s remained significantly predictive of secondary endpoints in the follow-up periods of 0-9 and 9-24months, during which clopidogrel was mostly discontinued.
  
  
  CONCLUSIONS
  This study demonstrates that increased residual platelet reactivity measured by PFA-100 CADP-CT consistently predicts the occurrence of cardiovascular events following PCI throughout the 24-month follow-up period, irrespective of the changes in anti-platelet use.
authors.affiliation: Cardiovascular Center and Department of Internal Medicine, National Taiwan University Hospital Yun-Lin Branch, Yun-Lin County, Taiwan.
authors.forename: Fu-Chun
authors.initials: FC
authors.lastname: Chiu
authors.forename: Tzung-Dau
authors.initials: TD
authors.lastname: Wang
authors.forename: Jen-Kuang
authors.initials: JK
authors.lastname: Lee
authors.forename: Fuh-Yuan
authors.initials: FY
authors.lastname: Shih
authors.forename: Jong-Wei
authors.initials: JW
authors.lastname: Lin
authors.forename: Chien-Hua
authors.initials: CH
authors.lastname: Huang
authors.forename: Wen-Jone
authors.initials: WJ
authors.lastname: Chen
authors.forename: Ming-Fong
authors.initials: MF
authors.lastname: Chen
mesh_terms: D000368:Aged; D015906:Angioplasty, Balloon, Coronary / Q000379:methods*; D001241:Aspirin / Q000008:administration & dosage*; D000077144:Clopidogrel; D004305:Dose-Response Relationship, Drug; D004359:Drug Therapy, Combination; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood / Q000453:epidemiology / Q000517:prevention & control*; D015539:Platelet Activation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage; D011300:Preoperative Care / Q000379:methods*; D011379:Prognosis; D012189:Retrospective Studies; D020521:Stroke / Q000097:blood / Q000453:epidemiology / Q000517:prevention & control*; D015996:Survival Rate / Q000639:trends; D013624:Taiwan / Q000453:epidemiology; D013988:Ticlopidine / Q000008:administration & dosage / Q000031:analogs & derivatives*; D013997:Time Factors
chemical_list: D010975:Platelet Aggregation Inhibitors; D000077144:Clopidogrel; D013988:Ticlopidine; D001241:Aspirin