Patent foramen ovale, systemic embolization and closure.

The recognition, evaluation and treatment of patent foramen ovale has attracted increasing interest as the importance and frequency of paradoxical embolism has become better understood. The interest in this field has been driven largely by the widespread application of echocardiography with identification of a patent foramen ovale and/or an atrial septal aneurysm. The evaluation of the role of a patent foramen ovale in patients with a neurologic event is complex because the patent foramen ovale or atrial septal aneurysm may either be an innocent bystander or could be the etiologic mechanisms involved in the paradoxical embolus. In patients younger than 55 years, a causal relationship between a patent foramen ovale/atrial septal aneurysm and a neurologic ischemic event is considerably stronger than in those patients older than 55 years. In patients with a presumed diagnosis of paradoxical embolus in the setting of a patent foramen ovale, percutaneous closure is now possible and 2 devices are relatively widely used. Both of these devices reliably close the defect with a very acceptable risk profile and have been found in the longer term to be associated with excellent outcome. The exact role, however, that these devices play vis a vis continued medical therapy for prevention of recurrent events is being tested in 2 randomized clinical trials. The field continues to change with new technology being developed and with new applications. A recently exciting finding has been the identification that closure of a patent foramen ovale may be associated with dramatic improvement in symptoms of patients with disabling migraine headaches. Other potential applications of these devices include those patients who are deep-sea divers, in whom the potential for "bends" exists, or high altitude airplane pilots.