Ann Thorac Surg 1997;63:1768-1770
© 1997 The Society of Thoracic Surgeons
Case Report
Torn Ascending Aorta Missed by Transesophageal Echocardiography
Scott D. Lick, MD,
Joseph B. Zwischenberger, MD,
William J. Mileski, MD,
Masood Ahmad, MD
Divisions of Cardiothoracic Surgery and General Surgery, Department of Surgery, and Division of Cardiology, Department of Medicine, The University of Texas Medical Branch, Galveston, Texas
Accepted for publication January 16, 1997.
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Abstract
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Transesophageal echocardiography has become a commonly used screening tool for traumatic tears of the descending aorta. The role of transesophageal echocardiography for ascending aortic tears is not yet well-defined. We report an ascending aortic tear imaged by aortography but missed on transesophageal echocardiography.
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Introduction
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Traumatic disruption of the ascending aorta is relatively uncommon. The most frequent site of aortic tear is just distal to the origin of the left subclavian artery (aortic isthmus) [1]. Transesophageal echocardiography (TEE) has become a commonly used screening tool for isthmic tears [2]. The descending aorta lies adjacent to the esophagus, and TEE images of the isthmic area are precise [3, 4]. The ascending aorta, however, is a middle mediastinal structure, separate from the esophagus. The role of TEE to evaluate or accurately describe ascending aortic tears has yet to be established.
We report a case of ascending aortic tear that was initially imaged by aortography but missed by subsequent TEE.
A 41-year-old, unrestrained male driver was found in the passenger seat after a single-vehicle high-speed accident. His injuries included an acetabular fracture, a cerebral contusion resulting in disorientation and combativeness, and a pulmonary contusion requiring orotracheal intubation. Initial chest radiography showed a widened mediastinum. An aortogram was then performed, which showed an outpouching in the lower ascending aorta (Fig 1
). To better image this area of the aorta, TEE was performed. Two cardiology attendings (both experienced in echocardiography) were shown the aortogram before performing TEE. The biplane probe was positioned in the esophagus, and during the procedure, the ascending aorta appeared normal during short-, long-, and off-axis views. There was no evidence of a false lumen, and no undulating intimal flap was seen. No flow disturbance was noted. The aortic wall thickness was normal. At the time, the TEE result was considered normal. Days later, a subsequent frame-by-frame search for an intimal flap showed a very localized linear density in the long-axis view projecting into the aortic lumen approximately 2 cm above the anterior aortic sinus. The echo density was less than 5 mm in length, and was seen on only three frames (Fig 2).
We chose to explore the patient's ascending aorta on the basis of the aortogram despite the absence of a demonstrable lesion by TEE. We cannulated the femoral artery, performed a median sternotomy, and found bloody pericardial fluid and blood staining of the periaortic fat. No aortic defect was palpable. We put the patient on cardiopulmonary bypass, cross-clamped the aorta, arrested the heart with retrograde cardioplegia, and opened the aorta with a standard aortic valve-type incision. Just above the left main coronary artery, opposite the pulmonary artery, we found a 3-cm, transverse, full-thickness aortic tear (Fig 3). The connective tissue between the aorta and pulmonary artery had contained the hematoma. After a small bridge of normal aorta was excised, both the tear and our aortotomy were closed with a single running 4-0 polypropylene stitch. The patient required several days of mechanical ventilation due to his pulmonary contusion, but went home on the 27th postoperative day.
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Fig 3. . A small full-thickness aortic tear contained by the connective tissue between the pulmonary artery and aorta.
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Comment
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Transesophageal echocardiography provides excellent images of the descending aorta. In one study of 160 consecutive patients undergoing TEE, aortography, or both to evaluate for blunt aortic injury, TEE was 100% sensitive and specific in detecting 14 traumatic descending aortic tears; this compared favorably with aortography, which was 79% sensitive and 99% specific [5]. Aortic dissection is not limited to one focal area, and usually includes the descending aorta. Erbel and associates [6] also found TEE more sensitive and specific in detecting dissection than aortography in their study of 164 consecutive patients, 82 of whom had aortic dissection (TEE, 99% sensitive and 98% specific; versus aortography, 88% and 94%) [6]. However, focal ascending aortic pathology may be difficult to demonstrate with TEE. Precise TEE imaging of the entire ascending aorta is limited by the following anatomic and technical constraints: (1) the arc of the aorta, which complicates longitudinal tomographic examination; (2) the trachea and right main bronchus, which separate the aorta from the esophagus, blocking echo penetration; and (3) the right pulmonary artery, a catheter in which will cast an echo artifact.
The distal ascending aorta is particularly difficult to see with TEE. Konstadt and associates [7] showed by intraoperative measurement of the ascending aorta during cardiac operations that TEE routinely failed to visualize the distal segment. The aortic cannula was seen in their study in only 1 of 27 patients. The difficulty in imaging this area is especially important in blunt trauma, because the distal ascending aorta is the second-most-common site of blunt aortic injury, after the isthmus.
In a case similar to ours, Catoire and co-workers [8] reported a low ascending aortic tear just above the right coronary artery takeoff that was missed by aortography but detected by TEE. Here, we report the converse: a case in which a low ascending aortic tear was missed by TEE but seen on aortography.
Aortography has been the time-proven standard to evaluate the aorta for tears. This case shows that a small, localized tear may not present with an easily identifiable intimal flap on TEE. The intimal separation can be extremely difficult to see, and a careful frame-by-frame search may be necessary to demonstrate the lesion. Given the anatomic constraints on TEE imagery of the ascending aorta, and the localized nature of blunt aortic injury, TEE alone may be inadequate in ruling out blunt ascending aortic pathology. If clinical suspicion is high, an aortogram should also be obtained.
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Footnotes
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Address reprint requests to Dr Lick, The University of Texas Medical Branch, 301 University Blvd, Rt 0528, Galveston, TX 77555-0528 (E-mail: Slick{at}mspo2.med.utmb.edu).
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References
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- Williams JS, Graff JA, Uku JM, Steinig JP. Aortic injury in vehicular trauma. Ann Thorac Surg 1994;57:726–30.[Abstract/Free Full Text]
- Vignon P, Gueret P, Vedrinne JM, et al. Role of transesophageal echocardiography in the diagnosis and management of traumatic aortic disruption. Circulation 1995;92:2959–68.[Abstract/Free Full Text]
- Seward JB, Khandheria BK, Oh JK, et al. Transesophageal echocardiography: technique, anatomic correlations, implementation and clinical applications. Mayo Clin Proc 1988;63:649–80.[Medline]
- Schneider MD, Hsu TL, Schwartz SL, Pandian NG. Single, biplane, and three-dimensional transesophageal echocardiography: echocardiographic-anatomic correlations. Cardiol Clinics 1993;11:361–87.[Medline]
- Buckmaster MJ, Kearney PA, Johnson SB, Smith MD, Sapin PM. Further experience with transesophageal echocardiography in the evaluation of thoracic aortic injury. J Trauma 1994;37:989–95.[Medline]
- Erbel R, Daniel W, Visser C, et al. Echocardiography in the diagnosis of aortic dissection. Lancet 1989;8636:457–61.
- Konstadt SN, Reich DL, Quintana C, Levy M. The ascending aorta: how much does transesophageal echocardiography see? Anesth Analg 1994;78:240–4.[Free Full Text]
- Catoire P, Bonnet F, Delaunay L, et al. Traumatic laceration of the ascending aorta detected by transesophageal echocardiography. Ann Emerg Med 1994;23:356–9.[Medline]
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Abstract
Introduction
