Is transesophageal echocardiography still necessary to exclude patent foramen ovale?

OBJECTIVES

Current guidelines still recommend transesophageal echocardiography (TEE) as reference method to diagnose interatrial shunts. The aim was to test the accuracy of high-end transthoracal echocardiography (TTE) to exclude inter-atrial shunts.

METHODS

Prospective TTE and TEE study with second harmonic imaging to determine left-to-right shunt (L/R) by both colour Doppler or R/L by contrast echocardiography in patients with unexplained cerebrovascular incidents or newly detected valvular or myocardial disease.

RESULTS

An inter-atrial shunt was diagnosed in 200 of 438 analyzed patients (117 males). Colour Doppler echocardiography visualized a shunt in 67 patients (34%) on TTE vs. 84 (42%) patients on TEE (p <0.0001). However injection of agitated blood with a valsalva maneuver detected 190 (95%) interatrial shunts by both TTE and TEE, but 10 shunts (5%) only by TTE.

CONCLUSIONS

Our study shows that patent foramen ovale can safely be demonstrated with high-end transthoracic contrast- echocardiography. If additional studies confirm our results, TTE has the potential to become the method of choice in the diagnosis of PFO.