[Paradoxal cerebral embolism: role of patent oval foramen]

A patent foramen ovale (PFO) is present in 25-35% of people at all ages of life and its size tends to increase with age. It is now possible to detect PFO's by contrast echocardiography and it has been shown that there exists quite frequently a spontaneous transient right-to-left shunt during systole and, moreover, a right-to-left shunt during Valsalva maneuver and coughing. Acute or chronic pulmonary hypertension are also causes of shunt. Besides, a highly statistical correlation has been found between PFO's and strokes of uncertain or absent cause. From 1984 to 1990 the authors have collected 29 cases with 47 embolic cerebral events. Twenty-five cases with 30 embolic cerebral events and a neurological report have been found in the literature from 1930 to 1986. The analysis of these 77 cerebral embolic events is presented. All ages and both sexes are equally affected. Several symptoms and signs can suggest the diagnosis: onset of the neurological disorders during an activity implying a Valsalva maneuver; onset during a recognized phlebitis of the legs of pelvis or, more often, in a clinical setting suggesting the possibility of phlebitis without overt symptoms and signs: post-partum, post-operative conditions with prolonged bed rest; concomitant pulmonary and cerebral embolism. In the authors series of 227 cerebral emboli, such paradoxical emboli account for 12.8% of the cases ant it is likely that the condition is still underdiagnosed.