Improvement in the diagnosis of bioprosthetic valve dysfunction by transesophageal echocardiography

Transthoracic two-dimensional echocardiography has been considered the method of choice for the non-invasive assessment of bioprosthetic valves. Recently, transesophageal echocardiography has provided a better imaging window for detecting valve abnormalities not identified otherwise, but pathologic confirmation is essential to establish the role of new diagnostic techniques in clinical practice. Therefore, the purpose of this study was to evaluate the usefulness of transesophageal echocardiography in determining the etiology of bioprosthetic valve dysfunction. Transthoracic and transesophageal two-dimensional and color-flow Doppler echocardiography were performed on 44 consecutive patients with suspected bioprosthetic dysfunction who underwent surgical intervention. At surgery a total of 63 abnormalities in 44 bioprostheses were identified: 31 (49.2%) flail cusps, 14 (22.2%) vegetations, four (6.3%) abscesses, four (6.3%) dehiscences, and 10 (15.9%) stenoses. Transesophageal echocardiography was superior to its transthoracic counterpart for the detection of flail cusps (96.7% vs. 54.8%, p < 0.01), vegetations (85.7% vs. 42.8%, p < 0.01), abscesses (100% vs. 25.0%, p < 0.05), and dehiscences (100% vs. 25.0%, p < 0.05). All patients with flail cusps had severe regurgitation as evaluated by color-flow Doppler. In bioprosthetic mitral stenosis, both methods provided accurate estimates of valve area, while in bioprosthetic aortic stenosis, transthoracic Doppler velocity measurements allowed calculation of valve area in four of six patients. In two patients with high flow velocities, the valve area was not estimated because of an inability to measure the left ventricular outflow tract dimension. Conversely, the transesophageal approach provided measurement of the outflow tract in all six patients, but Doppler velocities were not obtained in any of them.(ABSTRACT TRUNCATED AT 250 WORDS)