Patent foramen ovale and ischemic stroke in young people: statistical association or causal relation?

OBJECTIVES: 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. CONCLUSION: The causal relation between PFO and cryptogenic IS in the young population is highly probable. This fact should be considered in the therapeutic decision.