Echocardiographic findings mimicking type A aortic dissection.

BACKGROUND: Type A aortic dissection is a rare, but life-threatening disease. The prognosis is determined by an accurate and immediate diagnosis. CASE STUDY: A patient with suspected type A dissection based on outward transesophageal echocardiography (TEE) findings is reported. Renewed TEE showed dilation of the ascending aorta with pronounced wall thickness. A membrane-like structure was found in the ascending aorta. M-mode technique revealed movement of the suspected membrane that was partially in parallel to the aortic wall. Thus, there were severe doubts on the presence of type A dissection. By contrast, typical intimal rupture was found in the descending aorta. Computed tomography (CT) and angiography showed aortic dilation and an extended wall hematoma deriving from the entry at the descending part. There was no evidence of type A dissection.
CONCLUSION: TEE is a noninvasive diagnostic tool to assess aortic dissection of type A with a sensitivity of 90-98% that is equal to CT or magnetic resonance imaging (MRI) solely. Complementary use of CT or MRI could improve the diagnostic accuracy. False-positive findings could result from echocardiographic artifacts concealing an intimal flap in the ascending aorta. Echo reverberations in dilated or calcified aortas had been judged to account for this phenomenon. In the present case, it could be assumed that the extended wall hematoma in accordance with vessel dilation mimicked the membrane-like structure. Oscillation or flutter of the suspicious intimal flap independently of aortal wall movement seem to be mandatory to avoid false-positive diagnoses. Ancillary findings such as flow signals, intimal fenestration or thrombosis are helpful to enhance the diagnostic specificity of TEE.