| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
J Thorac Cardiovasc Surg 1996;112:1387-1389
© 1996 Mosby, Inc.
BRIEF COMMUNICATIONS |
Caen, France
Received for publication Feb. 21, 1996 Accepted for publication March 4, 1996. 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 poor exposure by the median sternotomy approach, we decided on a conservative strategy to avoid treating the uncomplicated descending aortic dissection. We also decided against inspecting the aorta from the inside with the aid of cardiopulmonary bypass because of the negative effects of systemic anticoagulation on the spontaneous evolution of thrombosis of the false lumen of a descending thoracic aorta dissection.
Another TEE investigation was performed after operation with the aid of a multiplanar probe (Hewlett-Packard model 21 364 A, 5 MHz multiplanar transducer; Hewlett-Packard Co., Medical Products Group, Andover, Mass.). It showed normal ascending and transverse aorta (Fig. 2), in contrast to the monoplane TEE study, and confirmed the descending aortic dissection. An artifact on monoplanar TEE dramatically simulating an aortic dissection was evident.
|
The close anatomic relationship between the esophagus and the vascular structures in the chest allows excellent image resolution of TEE. Recently introduced multiplanar TEE has further increased the sensitivity of this technique, providing more complete definition of the ascending aorta, aortic arch, and descending aorta. This improved definition overcomes some of the limitations of monoplanar TEE. The sensitivity of multiplanar TEE is estimated to range between 97% and 99%; the specificity ranges between 77% and 100%.
1
False-positive findings are mainly caused by acoustic artifacts in the ascending aorta, where aortic dilatation, wall atherosclerosis, and calcifications may lead to erroneous interpretations. Evangelista and colleagues 2 state that echocardiographic artifacts may occur in as many as 40% of patients with dilated aortic roots. Banning and associates 3 reported the case of a patient whose TEE showed a dissection of descending thoracic aorta and a linear shadow in the ascending aorta, which was interpreted as a dissection flap. Surgical inspection revealed an annuloaortic ectasia with dissection of the descending aorta below the origin of the left subclavian artery. That case, which is surprisingly similar to the one we describe here, shows that in emergency circumstances the knowledge of the risk of acute aortic dissection, with a mortality rate of 1% per hour, 4 may potentiate the risk of a false-positive diagnosis.
A retrospective blind review of single-plane TEE images was performed to investigate the possibility of individual interpretation bias. Five experienced readers were consulted, and all made the same diagnosis of acute dissection. They considered the finding of aortic root enlargement, associated with the intimal flap image in the presence of a descending aorta dissection especially suggestive of dissection.
Even if there is debate regarding the choice and the number of investigations to be performed, TEE plays a central role in the diagnosis of suspected dissections because of its accuracy, safety, convenience, and speed. In some institutions, TEE is the sole diagnostic investigation. 3 The goal of this report is to warn the surgical community about the risks of misleading information and incorrect decisions that can occur with monoplanar TEE because of artifacts. In urgent circumstances, even if the need to minimize delay appears to justify the desire to reduce the number of studies, reliable information is mandatory. We therefore believe that only highly accurate techniques such as multiplanar TEE should be employed in diagnosing aortic dissections.
Footnotes
From the Thoracic and Cardiovascular Department,a and the Cardiology Department,b University Hospital, Caen, France. 
J THORAC CARDIOVASC SURG 1996;112:1387-9
References
This article has been cited by other articles:
|
|
 |
|
  E. Neri, G. Capannini, E. Carone, E. Tucci, F. Diciolla, and C. Sassi THE MISSING FLAP: CONSIDERATIONS ABOUT A CASE OF AORTIC INTUSSUSCEPTION J. Thorac. Cardiovasc. Surg., April 1, 1999; 117(4): 829 - 830. [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| ANN THORAC SURG | ASIAN CARDIOVASC THORAC ANN | EUR J CARDIOTHORAC SURG |
| J THORAC CARDIOVASC SURG | ICVTS | ALL CTSNet JOURNALS |
