[The evaluation of the mechanism of mitral bioprosthesis malfunction by transesophageal echocardiography].

OBJECTIVES

The aim of this study was to assess the usefulness of transesophageal echocardiography for detection of the mechanism of dysfunction in bioprosthetic valves in the mitral position.

METHODS

Transthoracic and transesophageal echocardiograms were performed in 40 patients (mean age 61 +/- 12 years) with a dysfunctional bioprosthetic mitral valve. Echocardiographic results were compared to surgical findings in all except 1 patient.

RESULTS

All 9 patients with stenotic degenerated bioprosthesis were diagnosed by transthoracic and transesophageal echocardiography. Mechanism of dysfunction in the remaining patients were as follows: cusp tear or rupture in 18, dehiscence in 4 and endocarditis in 6. Transthoracic and transesophageal echocardiography visualized respectively: 8 (44%) and 15 (83%; p < 0.05) with cusp tears or ruptures; 3 (75%) and 3 (75%) with dehiscence; 3 (50%) and 6 (100%; p < 0.1) with endocarditis. One patient with pannus formation and 1 of 2 bioprosthetic thrombosis were not correctly identified by either echocardiographic technique.

CONCLUSIONS

Transesophageal echocardiography is suited for the assessment of mechanism of mitral regurgitation and for the diagnosis of vegetations in most of patients with bioprosthetic mitral valves. Transesophageal echocardiography adds little information to the transthoracic study in the evaluation of patients with stenotic bioprosthetic mitral valves, particularly in calcified degeneration.