Ann Thorac Surg 2008;86:e5-e6. doi:10.1016/j.athoracsur.2008.06.083
© 2008 The Society of Thoracic Surgeons
Case Reports
Patent Ductus Arteriosus Masquerading as Aortic Transection in a Trauma Victim
William Travis Lau, MD*,
David K.M. Wong, MD,
Henry W. Louie, MD
Department of Surgery, University of Hawaii, Honolulu, Hawaii
Accepted for publication June 27, 2008.
* Address correspondence to Dr Lau, Department of Surgery, University of Hawaii, 1356 Lusitana St, 6th Floor, Honolulu, 96813, Hawaii (Email: wlau01{at}hotmail.com).
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Abstract
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A high-speed motorcycle crash is a risk factor for thoracic aortic injury due to the rapid deceleration mechanism. We present a previously healthy 44-year-old man who was involved in a motorcycle accident. Initial spiral computed tomography indicated an intimal flap, which was visualized with evidence of mediastinal hemorrhage. The man was taken emergently to the operating room where a patent ductus arteriosus was seen at the location of the suspected aortic injury. No true aortic injury was appreciated.
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Introduction
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The most efficient way to diagnose an injury to the aorta in a situation with a blunt traumatic injury has been controversial. The aortogram has long been viewed as the "gold standard" for diagnosing aortic injury, but it is invasive and resource intensive. Spiral or helical computed tomography (CT) has become an acceptable modality to identify injury to the aorta. Spiral CT with intravenous contrast produces excellent images of vasculature, which are comparable with aortography [1]. In the presence of a high-speed deceleration mechanism of injury and clear unequivocal findings of aortic damage on spiral CT, aortography rarely provides additional diagnostic information, and the patient should be urgently taken to the operating room for repair [2–4].
A previously healthy, asymptomatic 44-year-old man presented to the emergency department after a high-speed motorcycle accident. The patient, who was driving a motorcycle, but was not wearing a helmet, avoided a collision with an oncoming van at high speed and was ejected from the motorcycle and landed on asphalt. When firefighters arrived at the scene the patient was alert, speaking, moving all extremities, and complaining of chest pain and shortness of breath. Paramedics arrived shortly thereafter, and due to the patient's increasing respiratory distress, he was intubated in the field and transported to the emergency department.
His vital signs on admission were temperature of 35.6°C, heart rate of 135 beats per minute, blood pressure of 162/100 mm Hg, oxygen saturation of 92% on bag-valve-mask ventilation. In the emergency department it was noted that the patient had a large left 8 x 6 cm temporal parietal hematoma, a 6-cm laceration in the right temporal parietal region, an 8-cm full thickness right iliac laceration, and multiple abrasions to the chest. On examination, he was intubated and sedated with coarse breath sounds bilaterally, and he was tachycardic. Initial multi-detector spiral CT scan with intravenous contrast revealed a moderate-sized right pneumothorax, right pleural effusion, a small left pneumothorax, rib fractures of the right second to eighth ribs and left fourth to sixth ribs, a fracture to the right ninth transverse process, multiple pulmonary contusions, and a thoracic aortic tear with mediastinal hemorrhage (Fig 1). Initial hemoglobin was 5 g/dL. The patient received 4 units of packed red blood cells, 7,000 cc normal saline, and bilateral chest tubes. Immediately after the chest tubes were inserted, 850 cc of blood was evacuated and the patient received an additional 4 units of packed red blood cells. When the spiral CT findings were reviewed with the radiologist, trauma surgeon, and thoracic surgeon, the patient was taken emergently to the operating room for correction of the suspected thoracic aortic tear.
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Fig 1. (A, B) Consecutive helical computed tomographic images with intravenous contrast. Arrows depict suggested intimal flap (IF). Asterisk identifies mediastinal hemorrhage (*).
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Intraoperative transesophageal echocardiography revealed imaging consistent with a tear in the descending thoracic aorta just below the level of the left subclavian artery with an intimal flap. During exploration through a left thoracotomy, it was clear that there were no aortic injury, hematoma, or discoloration of the aorta. Extensive circumferential exploration of the aorta in this area revealed no evidence of trauma to the thoracic aorta. There was no hematoma or palpable step-off in the area of the left subclavian vein proximal to the left subclavian artery. The patient is noted to have a well-defined, patent ductus arteriosus (Fig 2). After simple dissection and complete ligation of the patent ductus arteriosus, there was no further echocardiographic abnormality in this area. The patient tolerated the procedure well and was transferred back to the surgical intensive care unit for management of his other injuries. Approximately 1 month later, the patient recovered well from his injuries and was stable enough to return home.
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Comment
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The ductus arteriosus is present in fetal life as blood from the pulmonary artery bypasses the lungs and enters the descending aorta. The ductus normally closes after birth as a result of increased PO2 in the systemic circulation within the first six weeks of life, but rarely closes spontaneously after infancy. Patients with a small patent ductus arteriosus can be asymptomatic, but they are at a higher risk for infective endocarditis than the general population [5]. Those with a moderate to large-sized patent ductus arteriosus usually become symptomatic with fatigue and signs of left ventricular failure [6]. Surgical ligation of a patent ductus arteriosus has a mortality of less that 0.5% [5]. Aortography of the thoracic aorta can reveal a ductus diverticulum known as the "ductus bump." This normal variant is best seen in the left anterior oblique view and can mimic aortic injury due to its location at the insertion of the ligamentum arteriosum [7]. However, spiral CT is often a faster diagnostic modality and is becoming a preferred imaging technique for traumatic aortic injury.
In this case, the patient was previously asymptomatic and led an active lifestyle with no physical limitations secondary to his patent ductus arteriosus. With or without previous knowledge of this patient living with a patent ductus arteriosus, a motorcycle crash is well-established to be a risk factor for thoracic aortic injury [8, 9], coupled with unequivocal spiral CT findings and hemodynamic instability, emergent thoracotomy and surgical repair was indicated. We believe that there are no other published reports of a patent ductus arteriosus masquerading as an aortic transection in a trauma victim.
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References
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- Downing SW, Sperling JS, Mirvis SE, et al. Experience with spiral computed tomography as the sole diagnostic method for traumatic aortic rupture Ann Thorac Surg 2001;72:495-502.[Abstract/Free Full Text]
- Melton SM, Kerby JD, McGiffin D, et al. The evolution of chest computed tomography for the definitive diagnosis of blunt aortic injury: a single center experience J Trauma 2004;56:243-250.[Medline]
- Dyer DS, Moore EE, Ilke DN, et al. Thoracic aortic injury: how predictive is mechanism and is chest computed tomography a reliable screening tool?. A prospective study of 1,561 patients. J Trauma 2000;48:673-683.[Medline]
- Brickner ME, Hillis LD, Lange RA. Congenital heart disease in adults NEJM 2000;342:256-263.[Medline]
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- Malloy PC, Richard HM. Thoracic angiography and intervention in trauma Radiol Clin North Am 2006;44:239-249.[Medline]
- Greendyke RM. Traumatic rupture of aorta JAMA 1966;195:119-122.[Abstract/Free Full Text]
- Feczko JD, Lynch L, Pless JE, et al. An autopsy case review of 142 nonpenetrating (blunt) injuries of the aorta J Trauma 1992;33:846-849.[Medline]
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Abstract
Introduction
