title: Aspirin plus dipyridamole versus aspirin for prevention of vascular events after stroke or TIA: a meta-analysis.
abstract: OBJECTIVE
  This meta-analysis systematically reviewed randomized controlled trials comparing aspirin plus dipyridamole with aspirin alone in patients with stroke and TIA to determine the efficacy of these agents in preventing recurrent cerebral and systemic vascular events.
  
  
  METHODS
  We performed separate analyses of the incidences of stroke alone and composite outcome of stroke, myocardial infarction, or vascular death. We also performed two subset analyses, planned a priori, to examine effect size based on trials using (1) exclusively immediate-release and (2) predominantly extended-release dipyridamole.
  
  
  RESULTS
  The summary results indicate a significant reduction in the overall risk ratio in favor of aspirin plus dipyridamole for stroke alone with relative risk 0.77 (0.67 to 0.89) and the composite end point with relative risk 0.85 (0.76 to 0.94). Studies using immediate-release dipyridamole showed a nonstatistically significant trend in favor of the combination for stroke alone with relative risk 0.83 (0.59 to 1.15) and for the composite outcome with relative risk 0.95 (0.75 to 1.19). Studies using predominantly extended-release dipyridamole showed a statistically significant difference in favor of the combination for stroke alone with relative risk 0.76 (0.65 to 0.89) and for the composite outcome with relative risk 0.82 (0.73 to 0.92).
  
  
  CONCLUSIONS
  The combination of aspirin plus dipyridamole is more effective than aspirin alone in preventing stroke and other serious vascular events in patients with minor stroke and TIAs. The risk reduction was greater and statistically significant for studies using primarily extended release dipyridamole, which may reflect a true pharmacological effect or lack of statistical power in studies using immediate release dipyridamole.
authors.affiliation: Department of Neurology and Stroke Program, University of California, Sacramento, CA 95817, USA. piero.verro@ucdmc.ucdavis.edu
authors.forename: Piero
authors.initials: P
authors.lastname: Verro
authors.forename: Phillip B
authors.initials: PB
authors.lastname: Gorelick
authors.forename: Danh
authors.initials: D
authors.lastname: Nguyen
mesh_terms: D001241:Aspirin / Q000627:therapeutic use*; D004176:Dipyridamole / Q000627:therapeutic use*; D004359:Drug Therapy, Combination; D006801:Humans; D002546:Ischemic Attack, Transient / Q000150:complications / Q000188:drug therapy / Q000517:prevention & control*; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use*; D016032:Randomized Controlled Trials as Topic; D020521:Stroke / Q000150:complications / Q000188:drug therapy / Q000517:prevention & control*
chemical_list: D010975:Platelet Aggregation Inhibitors; D004176:Dipyridamole; D001241:Aspirin