title: Patent foramen ovale and ischemic stroke in young people: statistical association or causal relation?
abstract: OBJECTIVE
  To determine if there are evidences of a causal relation between patent foramen ovale (PFO) x cryptogenic ischemic stroke (IS) in the young population and to analyze this relation in terms of causal criteria.
  
  
  METHODS
  A total of 168 young patients with IS was retrospectively evaluated and divided into two groups: cryptogenic and with a defined cause. As a routine procedure, the patients underwent investigation of the PFO by means of transesophageal echocardiogram and/or transcranial Doppler sonography, both of them associated with the bubble test. Multivariate analysis was performed after demonstration of univariate statistical association between PFO x IS.
  
  
  RESULTS
  After multivariate analysis, the association between PFO x cryptogenic IS was still statistically significant with odds ratio (adjusted OR = 3.3; 95% CI: 1.5-7.4). The total number of cerebral lesions also presented a significant association with cryptogenic IS (adjusted OR = 0.4; 95% CI: 0.2-0.9). The association between PFO and cryptogenic IS met all the causality criteria.
  
  
  CONCLUSIONS
  The causal relation between PFO and cryptogenic IS in the young population is highly probable. This fact should be considered in the therapeutic decision.
authors.affiliation: Hospital SARAH, Brasília, DF, Brazil. emarcio@terra.com.br
authors.forename: Edson Marcio
authors.initials: EM
authors.lastname: Negrão
authors.forename: Ivar Viana
authors.initials: IV
authors.lastname: Brandi
authors.forename: Simone Vilela
authors.initials: SV
authors.lastname: Nunes
authors.forename: Daniel Gurgel Fernandes
authors.initials: DG
authors.lastname: Távora
authors.forename: Mauro
authors.initials: M
authors.lastname: Nakayama
authors.forename: Paulo Sergio Siebra
authors.initials: PS
authors.lastname: Beraldo
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D054092:Foramen Ovale, Patent / Q000150:complications* / Q000175:diagnosis; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D012189:Retrospective Studies; D012307:Risk Factors; D020521:Stroke / Q000209:etiology*