title: Patent foramen ovale in cryptogenic stroke: incidental or pathogenic?
abstract: OBJECTIVE
  Patent foramen ovale (PFO) is significantly associated with cryptogenic stroke (CS). However, even in patients with CS, a PFO can be an incidental finding. We sought to estimate the probability that a PFO in a patient with CS is incidental.
  
  
  METHODS
  A systematic search identified 23 case-control studies examining the prevalence of PFO in patients with CS versus control subjects with stroke of known cause. Using simple assumptions and Bayes' theorem, we calculated the probability a PFO is incidental in patients with CS. Random effects meta-analyses estimated the odds ratio (OR) of a PFO in CS versus control subjects in different age populations, with or without atrial septal aneurysms, and were used to summarize across studies the probability that a PFO in CS is incidental.
  
  
  RESULTS
  The summary OR (95% CIs) for PFO in CS versus control subjects was 2.9 (CI, 2.1 to 4.0). The corresponding ORs for young and old patients (< or >or=55 years) were 5.1 (3.3 to 7.8) and 2.0 (>1.0 to 3.7), respectively. The corresponding probabilities that a PFO in patients with CS is incidental were 33% (28% to 39%) in age-inclusive studies, 20% (16% to 25%) in younger patients, and 48% (34% to 66%) in older patients. These probabilities were much lower when an atrial septal aneurysm was present.
  
  
  CONCLUSIONS
  In patients with otherwise CS, approximately one third of discovered PFOs are likely to be incidental and hence not benefit from closure. This probability is sensitive to patient characteristics such as age and the presence of an atrial septal aneurysm, suggesting the importance of patient selection in therapeutic decision-making.
authors.affiliation: Institute for Clinical Research and Health Policy Studies, Division of Cardiology, Department of Medicine, Tufts Medical Center, Tufts University School of Medicine, Boston, MA 02111, USA.
authors.forename: Alawi A
authors.initials: AA
authors.lastname: Alsheikh-Ali
authors.forename: David E
authors.initials: DE
authors.lastname: Thaler
authors.forename: David M
authors.initials: DM
authors.lastname: Kent
mesh_terms: D000367:Age Factors; D001499:Bayes Theorem; D016022:Case-Control Studies; D054092:Foramen Ovale, Patent / Q000150:complications*; D006801:Humans; D033162:Incidental Findings; D008875:Middle Aged; D012307:Risk Factors; D020521:Stroke / Q000150:complications / Q000453:epidemiology*