Diagnosis and quantification of patent foramen ovale. Which is the reference technique? Simultaneous study with transcranial Doppler, transthoracic and transesophageal echocardiography.

INTRODUCTION AND OBJECTIVES Patent foramen ovale (PFO) is the most common cause of cryptogenic stroke in patients younger than 55. Transesophageal echocardiography (TEE) has been accepted as the reference diagnostic technique. The purpose of this study was to compare the accuracy of transthoracic echocardiography (TTE), TEE and transcranial Doppler (TCD) in the diagnosis and quantification of patent foramen ovale. METHODS We studied 134 patients prospectively. Simultaneous TTE with TCD and TEE with TCD were performed, using agitated saline solution to detect right to left shunt. RESULTS In 93 patients diagnosed with PFO, the shunt was visualized at baseline by TCD in 69% of cases, by TTE in 74% and by TEE in 58%. The Valsalva maneuver produced a similar improvement in shunt diagnosis with all 3 techniques (26%-28%). TTE and TCD showed higher sensitivity (100% vs 97%; non significant difference) than TEE in the diagnosis of PFO (86%; P<.001). TCD performed during TEE did not diagnose 12 (13%) shunts previously diagnosed during TTE. Similarly, TEE underestimated shunt severity. CONCLUSIONS TTE enables adequate diagnosis and quantification of PFO. TEE is less sensitive and tends to underestimate the severity of the shunt.