[The main indications for transesophageal echocardiography]

Transoesophageal echocardiography is one of the major technological advances over the last ten years; it allows imaging of unequalled quality for two main reasons: the proximity of the structures studied without interposition of pulmonary or parietal structures and the high resolution of the transducers used. Aortic dissection is the first main indication: the presence of an intimal flap confirms the diagnosis with a sensitivity and specificity of approximately 95% and 99%. This examination should be performed immediately whenever this diagnosis is suspected. Increasingly, the surgeon acts exclusively on the basis of these data. Acute endocarditis is another preferential indication: TOE is essential whenever the transthoracic image is imperfect, when fever persists or when valvular damage deteriorates despite well conducted antibiotic treatment, i.e. whenever an abscess is suspected. Thromboembolic accidents constitute a third indication for TOE. Three direct causes can be demonstrated:--thrombus in the left atrium or auricular appendage,--valve vegetation or tumour,--"intra-aortic debris", a recently identified cause. Abnormalities of the interatrial septum (aneurysm, PFO) raise difficult problems of causality and management. Valvular heart disease constitutes a fourth indication: in aortic stenosis, when transthoracic echocardiography is insufficient, TOE is able to obtain the valvular surface by direct planimetry in approximately 85% of cases. In the field of mitral incompetence, TOE is irreplaceable to define the mechanism of regurgitation and in the assessment of its severity. In mitral stenosis, however, its only value is to allow precise assessment mitral incompetence and detection of a thrombus. Suspension of dysfunction of a prosthetic valve constitutes another preferential indication for TOE: it allows much better visualization of thrombi, vegetations and the precise origin of periprosthetic leaks than transthoracic echocardiography. Finally, TOE is increasingly used intraoperatively and in intensive care.