title: Comparison of antiplatelet effects of aspirin, ticlopidine, or their combination after stent implantation.
abstract: BACKGROUND
  This study was performed to analyze the influence of either aspirin, ticlopidine, or their combination on platelet activation and aggregation parameters after stent implantation.
  
  
  RESULTS
  Sixty-one patients with successful implantation of a single Palmaz-Schatz stent in a native coronary artery were randomly assigned to either group A (aspirin 300 mg/d+ticlopidine 2X250 mg/d), group B (ticlopidine 2X250 mg/d), or group C (aspirin 300 mg/d). Platelet activation was evaluated on days 1, 7, and 14 by flow cytometry measurement of expression of CD62p (p-selectin) and the binding of fibrinogen to the platelet surface glycoprotein IIb/IIIa receptor. Platelet aggregation was induced by addition of ADP or collagen. Differences between treatment groups were compared by ANOVA. Between days 1 and 14, we observed a significant decrease in collagen-induced platelet aggregation in group A (62.2+/-2.5% versus 36.9+/-3.1%), whereas an increase was seen in group B (58.3+/-2.5% versus 67.7+/-3.2%) and no change was seen in group C (P<.0001). The ADP-induced aggregation declined significantly in group A (74.7+/-1.4% versus 55.3+/-2.6%), whereas a delayed reduction was seen in group B (72.0+/-3.0% versus 52.6+/-4.2%) and no change was seen in group C (P=.0017). The CD62p expression declined significantly in groups A (68.2+/-2.7% versus 41.3+/-2.7%) and B (64.8+/-2.9% versus 39.3+/-3.5%) but not in group C (P<.0001). Moreover, the fibrinogen binding decreased significantly in group A (61.0+/-4.3% versus 36.3+/-4.2%) and with delay in group B (58.3+/-2.2% versus 39.4+/-3.0%), whereas no alterations were seen in group C (P=.012).
  
  
  CONCLUSIONS
  Our results demonstrate synergistic and accelerated platelet inhibitory effects of ticlopidine plus aspirin in patients after stent implantation compared with a monotherapy with either ticlopidine or aspirin alone.
authors.affiliation: Department of Medicine II, Johannes Gutenberg University, Mainz, Germany.
authors.forename: H J
authors.initials: HJ
authors.lastname: Rupprecht
authors.forename: H
authors.initials: H
authors.lastname: Darius
authors.forename: U
authors.initials: U
authors.lastname: Borkowski
authors.forename: T
authors.initials: T
authors.lastname: Voigtländer
authors.forename: B
authors.initials: B
authors.lastname: Nowak
authors.forename: S
authors.initials: S
authors.lastname: Genth
authors.forename: J
authors.initials: J
authors.lastname: Meyer
mesh_terms: D015906:Angioplasty, Balloon, Coronary; D001241:Aspirin / Q000494:pharmacology / Q000627:therapeutic use*; D003327:Coronary Disease / Q000628:therapy; D004359:Drug Therapy, Combination; D005340:Fibrinogen / Q000378:metabolism; D006801:Humans; D019007:P-Selectin / Q000032:analysis; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology / Q000627:therapeutic use*; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000378:metabolism; D015607:Stents; D013988:Ticlopidine / Q000494:pharmacology / Q000627:therapeutic use*; D013997:Time Factors
chemical_list: D019007:P-Selectin; D010975:Platelet Aggregation Inhibitors; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D005340:Fibrinogen; D013988:Ticlopidine; D001241:Aspirin