[Paradoxical embolism through a patent foramen ovale. 4 cases]

Abstract

Four cases of paradoxical embolism through a patent foramen ovale associated with massive pulmonary embolism are reported. In two cases, patency of the foramen ovale was demonstrated by a new technique: cross-sectional contrast echocardiography potentiated by coughing. The conventional surgical treatment included arterial embolectomy followed by insertion of a caval filter. Embolism recurred on three occasions under mechanical ventilation prior to insertion of the filter. A new sequence of investigations to facilitate detection of paradoxical embolism in patients with unexplained arterial embolism is suggested: (1) blood gas measurements, which reveal associated pulmonary embolism; (2) cough-potentiated cross-sectional contrast echocardiography, which demonstrates a patent foramen ovale and excludes emboligenic cardiopathies; (3) phlebography and pulmonary angiography which complete the diagnosis. To reduce the risk of recurrent embolism, it is recommended to begin treatment by blocking the vena cava without mechanical ventilation. This can be done by inserting a filter through the jugular vein under local anaesthesia. Arterial embolism can then be treated at lesser risk under mechanical ventilation.