Usefulness of the echocardiographic paravertebral approach for the diagnosis of descending thoracic aortic dissection.

Background: Transthoracic echocardiography (TTE) is not recommended as the first-line diagnostic modality for Stanford type B aortic dissection (type-B AD).

Purposes: The aims of this study were to evaluate the usefulness and factors influencing for the diagnosis of type-B AD using the transthoracic echocardiographic paravertebral approach (PVA).

Methods: We compared the image acquisition rate of descending thoracic aorta (DTA) and the diagnostic rate of type-B AD using TTE versus PVA. Both tests were compared with type-B AD, which was diagnosed by enhanced computed tomography (CT), as the reference standard. We also analyzed the factors influencing adequate image acquisition and the diagnosis of type-B AD using the PVA. The length between the dorsal thoracic surface and the DTA (TDAL) and thickness of lung on the TDAL line (LTh) were measured on the CT images.

Results: No significant difference was found between the image acquisition rate of the DTA between the PVA and the TTE (70.1 vs. 64.2%, p = 0.56), while the diagnostic rate of type-B AD using the PVA was significantly greater than when using the TTE (56.7 vs. 26.9%, p < 0.001). Furthermore, when adequate images of DTA were obtained using the PVA, 80.9% of the patients were diagnosed with type-B AD. A multivariate analysis demonstrated that a lower LTh (p = 0.001) and the existence of a pleural effusion (p = 0.03) significantly influenced the diagnosis of type-B AD using the PVA.

Conclusions: The PVA might be a useful method for diagnosis of type-B AD, when adequate images of the DTA are obtained.