Transesophageal Contrast Echocardiography is Not Always the Gold Standard Method in the Identification of a Patent Foramen Ovale: A Clinical Case.

In the embryo, Eustachian valve is a crescent-shaped membrane extending from the lower margin of the inferior vena cava and the ostium of the coronary sinus into the right atrium toward fossa ovalis and tricuspid valve. At birth, after the functional closure of the foramen ovale, the Eustachian valve loses its function, reducing to an embryo remnant. According to growing evidence, a persistent Eustachian valve is a frequent finding in patients with a patent foramen ovale (PFO). By directing the blood from the inferior cava to the interatrial septum, it may prevent the spontaneous closure of PFO after birth and indirectly predispose to paradoxical embolism. Transesophageal contrast enhanced echocardiography (cTEE) is considered the gold standard to diagnose a PFO in postnatal life, but its accuracy maybe is not so high in the presence of a persistent Eustachian valve. In these cases, color Doppler TEE is more sensitive and simplifies the diagnostic process, reducing the duration of TEE and improving the patient compliance.