title: Systematic review of the clinical impact of dual antiplatelet therapy discontinuation after acute coronary syndromes.
abstract: OBJECTIVE
  The aim of this systematic literature review was to assess the consequences of dual antiplatelet therapy discontinuation on clinical outcomes after acute coronary syndromes.
  
  
  RESULTS
  A systematic literature search was conducted in PubMed to identify studies reporting data on patients who discontinued dual antiplatelet therapy (planned or unplanned) following acute coronary syndromes and on the clinical impact of dual antiplatelet therapy discontinuation. To be included, more than 50% of the study population had to have had acute coronary syndrome as their index event or, if less than 50%, outcomes data must have been reported separately for the group with acute coronary syndromes. Thirty publications covering 29 studies were identified for inclusion. There was much heterogeneity across studies regarding the included patient populations, treatment durations and outcome definitions and ascertainments. Dual antiplatelet therapy discontinuation was most commonly based on physician decision. Twenty-six studies reported that clopidogrel was prescribed as part of dual antiplatelet therapy. Dual antiplatelet therapy duration was positively associated with a lower risk of all-cause mortality (seven/eight studies), cardiovascular mortality (two/two studies), non-fatal myocardial infarction (two/three studies) and stent thrombosis (five/five studies) in patients and/or patient subgroups in studies without randomised treatment designs, although such associations were not observed in the one study that randomly assigned patients to treatment (i.e. planned discontinuation).
  
  
  CONCLUSIONS
  Results from our systematic literature review generally support the benefit of longer-term dual antiplatelet therapy after acute coronary syndromes; however, further research is needed to determine the optimal length of dual antiplatelet therapy in patients after acute coronary syndrome, ideally using prospective studies.
authors.affiliation: 1 Klinikum Ludwigshafen, Institut für Herzinfarktforschung, Germany.
authors.forename: Uwe
authors.initials: U
authors.lastname: Zeymer
authors.affiliation: 2 Research and Evaluation Unit, Oxford PharmaGenesis Ltd, UK.|3 School of Medicine, Pharmacy and Health, Durham University, UK.
authors.forename: Anja
authors.initials: A
authors.lastname: Becher
authors.affiliation: 4 AstraZeneca, Cambridge, UK.
authors.forename: Em
authors.initials: E
authors.lastname: Jennings
authors.affiliation: 5 AstraZeneca Gothenburg, Mölndal, Sweden.
authors.forename: Saga
authors.initials: S
authors.lastname: Johansson
authors.affiliation: 4 AstraZeneca, Cambridge, UK.
authors.forename: Mogens
authors.initials: M
authors.lastname: Westergaard
mesh_terms: D054058:Acute Coronary Syndrome / Q000188:drug therapy*; D001241:Aspirin / Q000627:therapeutic use*; D000077144:Clopidogrel; D004359:Drug Therapy, Combination; D006801:Humans; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use; D011379:Prognosis; D013988:Ticlopidine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D013997:Time Factors; D028761:Withholding Treatment
chemical_list: D010975:Platelet Aggregation Inhibitors; D000077144:Clopidogrel; D013988:Ticlopidine; D001241:Aspirin
keywords: Acute coronary syndromes; discontinuation; dual antiplatelet therapy