title: Bleeding risk associated with 1 year of dual antiplatelet therapy after percutaneous coronary intervention: Insights from the Clopidogrel for the Reduction of Events During Observation (CREDO) trial.
abstract: BACKGROUND
  The optimal duration of dual antiplatelet therapy after percutaneous coronary intervention (PCI) is unknown. Incremental reductions in the risk of major adverse cardiovascular events may be partially offset by an increased incidence of bleeding in the months after a PCI.
  
  
  METHODS
  We examined the incidence, severity, and predictors of bleeding associated with 1 year of dual antiplatelet therapy after PCI among 1,816 patients in the Clopidogrel for the Reduction of Event During Observation (CREDO) trial. We also compared bleeding in patients who received dual antiplatelet therapy for 1 year to those who did so for only 4 weeks. Bleeding was categorized as major or minor using the modified Thrombolysis In Myocardial Infarction (TIMI) Study Group criteria.
  
  
  RESULTS
  Major or minor bleeding occurred in 146 patients during 1 year of follow-up. More than 80% of bleeding events were periprocedural. Multivariable predictors of any bleeding included increasing age and coronary artery bypass. Any (major or minor) bleeding occurred in 71 (8.1%) and 77 (8.9%), major bleeding in 34 (3.9%) and 49 (5.6%), and minor bleeding in 37 (4.2%) and 29 (3.3%) of placebo- and clopidogrel-treated patients, respectively; these differences were not significant. However, major gastrointestinal bleeding occurred in significantly more clopidogrel- than placebo-treated patients (13 [1.4%] vs 3 [0.3%] [P = .011]).
  
  
  CONCLUSIONS
  Adding clopidogrel to aspirin beyond 4 weeks post PCI is not associated with a significant increase in the overall rate of major or minor bleeding, although it is associated with an increase in major gastrointestinal bleeding in the year after a PCI.
authors.affiliation: Clinical Scholars Program, Michigan Heart and Vascular Institute at St. Joseph Mercy Hospital, Ann Arbor, USA. haronow@michiganheart.com
authors.forename: Herbert D
authors.initials: HD
authors.lastname: Aronow
authors.forename: Steven R
authors.initials: SR
authors.lastname: Steinhubl
authors.forename: Danielle M
authors.initials: DM
authors.lastname: Brennan
authors.forename: Peter B
authors.initials: PB
authors.lastname: Berger
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Topol
mesh_terms: D000368:Aged; D015906:Angioplasty, Balloon, Coronary; D001241:Aspirin / Q000008:administration & dosage / Q000009:adverse effects*; D000077144:Clopidogrel; D003324:Coronary Artery Disease / Q000628:therapy; D004359:Drug Therapy, Combination; D005260:Female; D006471:Gastrointestinal Hemorrhage / Q000139:chemically induced / Q000453:epidemiology; D006470:Hemorrhage / Q000139:chemically induced* / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage / Q000009:adverse effects*; D013988:Ticlopidine / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives*; D013997:Time Factors
chemical_list: D010975:Platelet Aggregation Inhibitors; D000077144:Clopidogrel; D013988:Ticlopidine; D001241:Aspirin