Patent foramen ovale: indications for closure and techniques.

Non-surgical closure of the patent foramen ovale (PFO) has been possible for 40 years and proved safe in probably a million cases performed worldwide. Nonetheless, indications are still restricted as only a few are supported by randomised data. Paradoxical embolism through a PFO causes stroke, myocardial infarction, and visceral or peripheral ischaemia. The PFO is a likely mediator of migraine, diving or high altitude sickness, dyspnoea, and sleep apnoea problems. As untoward effects of a PFO are rare and spaced widely timewise, large cohorts and long follow-ups are required to prove unequivocally that PFO closure is bene-ficial and appropriate in comparison to no treatment or medical therapy. The most compelling respective randomised data have been gathered so far in the realm of secondary prevention of cerebral attacks and migraine. Invariably they showed a numerical advantage of PFO closure with significant difference in sub-analyses. Evidence-based medicine carries a danger of underutilising valuable therapies while accumulating further data. PFO closure is an example. Its documented innocuousness invites a more proactive reflection in upcoming guidelines. At worst, PFO closure may not convey the projected amount of benefit. This even opens the door for primary prevention in some PFOs with high-risk characteristics.