Cryptogenic stroke in patients with patent foramen ovale.

Paradoxical embolism through a patent foramen ovale (PFO) is a commonly identified potential mechanism of ischemic stroke, especially in young patients. The recurrent stroke rate among young cryptogenic stroke patients with a PFO is modest, but higher than normal for their age. Co-existing atrial septal aneurysm is a substantial, and the only definite, potentiator of stroke risk in patients with PFO, but PFO size, degree of functional shunting, and co-existing hypercoagulable state likely are additional risk factors. Pelvic CT and magnetic resonance venography have improved our ability to detect source venous thromboemboli and underlie new management strategies. Treatment strategies for PFOs in ischemic stroke patients include antiplatelet agents, anticoagulants, surgical closure, or percutaneous closure devices. The completion of ongoing, randomized clinical trials comparing percutaneous closure devices with medical management is likely to be hastened by the recent withdrawal of humanitarian device exemption approvals, and is urgently needed to clarify if the risks of invasive endovascular device placement are outweighed by a long-term reduction in recurrent vascular events.