False-positive diagnosis of ascending aorta dissection by single-plane transesophageal echocardiography

Abstract

Acute descending thoracic aorta dissection was diagnosed on the basis of a contrast computed tomographic scan in a 72-year-old hypertensive man with acute chest pain. At physical examination, the patient was in stable condition, all pulses were present, arterial pressure was 180/85 mm Hg, and a mild aortic diastolic murmur was audible. Electrocardiography showed a 62 beat/min normal sinus rhythm, with no signs of ischemia. Chest radiography showed a moderate mediastinal enlargement. At contrast computed tomographic scan, the descending thoracic aorta showed the signs of acute dissection, with a false lumen with low flow inside evidenced by poor opacification and without evidence of reentry. The transverse aorta was not well visualized, and it was not possible to detect the upper limit of the dissection. The ascending aorta appeared dilated, but no intimal flap could be identified. We decided to perform transesophageal echocardiography (TEE). We used the Aloka MNI-0260-2, 5 MHz monoplanar transducer (Aloka, Co., Ltd., Tokyo, Japan), which showed an important dissection extending from the innominate artery into the ascending aorta. The ascending aorta appeared dilated, and a flap could be seen above the aortic valve (Fig. 1). No intimal tear was seen, suggesting a retrograde dissection mechanism. Mild aortic valve regurgitation was also noted, and no pericardial effusion was seen. Monoplanar TEE confirmed the presence of a dissection with low flow within the false lumen in the descending thoracic aorta. Because of the dramatic aspect of the lesion and the suspicion of a retrograde dissection of ascending and transverse aorta, we decided to operate on the patient without delay. A median sternotomy was decided on because of the involvement of the ascending aorta in the dissection. The left common femoral artery was prepared, and the cervical region was included in the operative field. Intraoperative inspection showed a moderately dilated ascending aorta with neither hematoma nor aortic wall abnormality. When the aortic arch was completely exposed, no signs of dissection were detected along the