Patent foramen ovale and cryptogenic stroke. A critical review.

The underlying causes of ischemic stroke in young patients are often difficult to find, despite systematic investigations concerning heart, coagulation system or any other type of vascular disease, thus the definition of 'cryptogenic'. In patients with cryptogenic stroke, the prevalence of a patent foramen ovale is about 45%, versus 25% of the general healthy population, leading to many speculations about a potential role of intracardiac right-to-left shunts in determining ischemic cerebral disease. Since a possible mechanism has been thought to be paradoxical embolism, percutaneous closure of the foramen ovale is currently discussed, at least until the appearance of data from the ongoing randomized trials. However, recurrent paradoxical embolism in patients with an aneurysmal atrial septum and a patent foramen ovale is currently the only unequivocal indication for percutaneous closure. Professional divers may benefit from the procedure as well, whereas migraine is still not considered an indication. In the pediatric population, closure of the patent foramen ovale seems to be safe and effective to prevent recurrent stroke. As the complication rate for device implantation decreases, the threshold for percutaneous closure is likely to decline.