[The usefulness of transesophageal echocardiography in assessing mechanical mitral prostheses. A comparison with transthoracic echocardiography].

One hundred and sixty mechanical mitral prostheses were studied by transoesophageal echocardiography to ascertain the role of this technique in their functional assessment. All patients underwent transoesophageal echocardiogram, and, in 83, transthoracic Doppler-echocardiogram had already been performed immediately prior to transoesophageal echocardiogram. Prostheses presenting structural anomaly on bidimensional image and/or areas of regurgitation with predominantly turbulent flow on colour Doppler were considered to be dysfunctional. Of the 160 prostheses, 115 were considered normofunctional, and regurgitation was detected in 85 (94%) by transoesophageal echocardiogram and 10 (9%) by transthoracic echocardiogram; haemodynamic and/or surgical confirmation was obtained in 6 of these prostheses and all proved to be functioning normally. Of the 45 remaining prostheses considered to be dysfunctional, haemodynamic and/or surgical confirmation was obtained in 21 (the non-confirmed 24 were excluded from the study). Seventeen of the dysfunctional prostheses presented with areas of regurgitation of 3.9-24 cm2 (mean: 9.21 + 5.36); in one case, the degree of regurgitation with respect haemodynamic study was over-assessed; transthoracic echocardiogram detected only periprosthetic leaks in 38% of cases, with areas of regurgitation of 1.8-6.3 cm2 (mean: 1.87 + 2.02). The other 4 dysfunctional prostheses presented dysfunction due to thrombosis; all 4 were diagnosed by both transthoracic and transoesophageal echocardiogram. Transoesophageal echocardiogram detected 12 structural anomalies (1 vegetations, 4 thromboses and 7 dehiscencies), whereas transthoracic echocardiogram only detected these anomalies in five of the cases (1 vegetations and 4 thromboses). Transoesophageal echocardiography surpasses transthoracic echocardiography in the assessment of mechanical mitral prostheses and dysfunction diagnosis.(ABSTRACT TRUNCATED AT 250 WORDS)