Recent investigations of patients with cerebral and peripheral arterial emboli of unknown cause suggest that paradoxical embolism through a patent foramen ovale (PFO) might be responsible for more arterial embolic events than previously realized. In most cases, however, a causal relationship between the embolic process and the PFO cannot be established with certainty. The presumptive nature of the clinical diagnosis of paradoxical embolism together with the lack of precise data on the risk of recurrent embolization do not facilitate the proper treatment of these patients. In the rare case of proved paradoxical embolism with a thrombus straddling a PFO discovered by echocardiography, the available literature suggest that embolectomy and closure of the PFO is the most logical approach. The long-term treatment of patients with presumed paradoxical embolism is controversial. Further studies are needed to assess the risk of recurrent arterial ischemic events associated with PFO, to determine which patients are at increased risk of recurrent events, and to assess the potential benefits from various therapeutic interventions (anticoagulants or antiplatelet drugs, surgical or transcatheter closure of the PFO). Otherwise, we risk exposing these patients to unnecessary treatment complications.
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