Diagnostic accuracy of transthoracic and transesophageal echocardiography for the diagnosis of bicuspid aortic valve: comparison with operative findings.

Background: Bicuspid aortic valve (BAV) is associated with an increased risk of aortic valve (AV) dysfunction, aortic dissection, and infective endocarditis. Therefore, its accurate diagnosis is critical. The morphological features of AVs are generally evaluated by transthoracic echocardiography (TTE) or transesophageal echocardiography (TEE), however, the difference in the diagnostic capability of these imaging modalities for detecting BAV remains unclear. Here, we compared these 2 methods to determine their accuracy, and to clarify each role in the diagnosis of BAV.

Methods: This blind study evaluated 126 patients (age, 70.3 +/- 7.8 years) who subsequently underwent AV replacement. The number of AV cusps of each patient was estimated by TTE and TEE and compared to the number of AV written in the operative record. Patients with poor echocardiographic images were not excluded.

Results: Surgical findings showed 97 tricuspid AVs and 29 BAVs. The sensitivity, specificity, and accuracy for the diagnosis of BAV were 61%, 81%, and 77%, respectively, for TTE and 86%, 90%, and 89%, respectively, for TEE. The accuracy of TEE was significantly higher than that of TTE (p = 0.016). In non-calcified AVs, the accuracy of TTE was similar to that of TEE (96%, each) whereas in calcified AVs, TTE had a lower accuracy than TEE (72% vs 87%, p = 0.011). The feasibility was significantly higher for TEE than for TTE (98% vs 90%, p = 0.003).

Conclusions: TEE provides higher accuracy and feasibility than TTE in the diagnosis of BAV, and it should therefore be indicated when morphological features of AVs cannot be evaluated by TTE.