Management of the stroke patient with patent foramen ovale: new insights and persistent questions in the wake of recent randomized trials.

Stroke without a known cause, or cryptogenic stroke, accounts for up to 30 % of all ischemic strokes. Paradoxical embolism through a patent foramen ovale (PFO) has been implicated as a potential cause of cryptogenic cerebral ischemia, particularly in young patients. Epidemiological studies have noted an association between PFO and cryptogenic stroke and observational studies have suggested the potential superiority of percutaneous PFO closure over medical therapy. However, until recently, there were no randomized data to test the hypothesis that PFO closure reduces the risk of recurrent cerebral ischemia. The publication of three such trials, all failing to demonstrate a therapeutic advantage for closure over medical therapy in intention-to-treat analyses, provides valuable new data in the field. We review epidemiological evidence linking PFO and stroke and recent observational and randomized trial data evaluating different treatment strategies.