[Patent foramen ovale. What is it and what does it indicate?]

Cryptogenic stroke accounts for up to 40 % of all ischemic strokes and is even more frequent in young patients. The patent foramen ovale (PFO) is found in almost 60% of these young patients and has been suggested as a potential cause of cryptogenic stroke in this age group. However, the pathological relevance of PFO in cryptogenic stroke and the most appropriate therapeutic handling of it have not been established. In this review, the current state of therapeutic handling and ongoing controversies are discussed and the most interesting results in this field, including recent metaanalyses, are presented.