Advances and ongoing controversies in PFO closure and cryptogenic stroke.

Approximately one-third of strokes are cryptogenic in origin. These patients have a higher prevalence of patent foramen ovale (PFO) compared to individuals with stroke of known origin. It has been proposed that some cryptogenic strokes (CSs) can be caused by paradoxical embolism across a PFO. PFOs can be treated medically with antithrombotic agents and percutaneously with occluder devices. Large randomized clinical trials have found transcatheter PFO closure to be superior to medical treatment for the prevention of recurrent stroke in young patients with CS. However, the superiority of PFO closure over medical treatment in unselected populations has not been demonstrated. In this chapter, we review the evidence supporting PFO closure and the selection of patients for such intervention.