title: Platelet function in patients with acute coronary syndrome (ACS) predicts recurrent ACS.
abstract: BACKGROUND
  Platelet hyperfunction contributes to acute coronary syndromes (ACS). Thus, we hypothesized that platelet function under high shear stress predicts recurrent ACS during long-term follow-up of ACS patients.
  
  
  METHODS
  Consecutive ACS patients (n = 208) were prospectively followed-up for an average of 28 months. Platelet function was measured with the platelet function analyzer (PFA-100; Dade Behring, Marburg, Germany) at baseline for collagen/adenosine diphosphate closure times (CADP-CT) and for collagen/epinephrine closure times (CEPI-CT) after infusion of a uniform dose of 250 mg aspirin.
  
  
  RESULTS
  Of the conventional risk factors, only the prevalence of diabetes was higher in ACS patients with re-events. However, use of clopidogrel and use of beta blockers were also slightly lower in patients with re-events (P < 0.05). The unadjusted risk hazard ratio (HR) for re-events was 3.3 [95% confidence interval (95% CI): 1.4-7.4; P = 0.005] in those patients with the shortest CADP-CT values (lowest quartile). Similarly, the risk was 2.0-fold higher (95% CI: 1.1-3.6; P = 0.02) in ACS patients with CEPI-CT < 300 s as compared with CEPI-CT >or = 300 s. Inclusion of diabetes, clopidogrel and beta blockers in a multivariate Cox regression model enhanced the predictive value of CEPI-CT (HR: 2.7). Inclusion of von Willebrand factor levels did not alter the HR for recurrent ACS (HR: 2.1; 95% CI: 1.1-5.2; P = 0.03) for CEPI-CT < 300 s, but reduced the HR for CADP-CT (HR: 2.8, 95% CI: 0.8-9.8; P = 0.11).
  
  
  CONCLUSIONS
  Shortened CT values reflect biologically relevant platelet hyperfunction in patients with ACS because they predict recurrent ACS.
authors.affiliation: Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria.
authors.forename: I
authors.initials: I
authors.lastname: Fuchs
authors.forename: M
authors.initials: M
authors.lastname: Frossard
authors.forename: A
authors.initials: A
authors.lastname: Spiel
authors.forename: E
authors.initials: E
authors.lastname: Riedmüller
authors.forename: A N
authors.initials: AN
authors.lastname: Laggner
authors.forename: B
authors.initials: B
authors.lastname: Jilma
mesh_terms: D000208:Acute Disease; D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use; D001241:Aspirin / Q000494:pharmacology; D000077144:Clopidogrel; D003327:Coronary Disease / Q000097:blood* / Q000188:drug therapy / Q000209:etiology / Q000401:mortality / Q000517:prevention & control*; D048909:Diabetes Complications / Q000097:blood; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D015539:Platelet Activation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology / Q000627:therapeutic use; D010979:Platelet Function Tests; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012008:Recurrence; D012107:Research Design; D018570:Risk Assessment; D013314:Stress, Mechanical; D013577:Syndrome; D013988:Ticlopidine / Q000031:analogs & derivatives / Q000627:therapeutic use; D013997:Time Factors; D014841:von Willebrand Factor / Q000378:metabolism
chemical_list: D000319:Adrenergic beta-Antagonists; D010975:Platelet Aggregation Inhibitors; D014841:von Willebrand Factor; D000077144:Clopidogrel; D013988:Ticlopidine; D001241:Aspirin