Patent Foramen Ovale, Risk of Stroke Recurrence and Secondary Prevention Outline of Current Evidence

In current treatment of stroke there are still substantial uncertainties about the appropriate secondary prevention for patients with patent foramen ovale (PFO) after first-ever ischaemic stroke. The contentious issue takes on greater significance by the possibility of interventional PFO closure with sharply growing numbers of interventions in the last few years. In the year 1991 the first implicit evidence of a right-to-left shunt via transcranial detection of emboli after i.v. contrast agent administration (c-TCD) was described and can be considered as a slightly invasive diagnostic tool with sufficient sensitivity and specificity. Currently conducted studies by means of c-TCD and multivariate analysis were not able to verify a causal relationship between PFO and stroke, which was often described in some small, mainly case-control, studies, and brought up the question if this statistical relationship has mainly been brought about by confounding, as age and gender of PFO patients have been disregarded in early studies. Notwithstanding the above, results of multicentric studies show that PFO is not associated with recurrent stroke. Furthermore, neither shunt volume nor concomitant atrial septal aneurysm have a significant impact on the recurrence of stroke. Therefore, there is no sustainable evidence for oral anticoagulation in patients with PFO. Furthermore, an interventional PFO closure should be rejected since the results of the closure I study.