Ann Vasc Dis Vol. 7, No. 2; 2014; pp 165–168 ©2014 Annals of Vascular Diseases

Online Month May 16, 2014 doi:10.3400/avd.cr.13-00117

Case Report

Successful Surgical Treatment of Traumatic Transection of the Innominate Artery: A Case Report Yasuyuki Bito, MD, PhD, Hidekazu Hirai, MD, PhD, Yasuyuki Sasaki, MD, PhD, Mitsuharu Hosono, MD, PhD, Atsushi Nakahira, MD, PhD, Yasuo Suehiro, MD, Daisuke Kaku, MD, Yuko Kubota, MD, PhD, Makoto Miyabe, MD, and Shigefumi Suehiro, MD, PhD

Blunt traumatic injury to the innominate artery is relatively rare. We present the case of a 40-year-old woman who fell from a fourth-floor window and was transferred to our hospital with multiple injuries, hemodynamic shock, and disturbance of consciousness. Computed tomography with image reconstruction revealed transection of the innominate artery near its origin. Emergent surgery required establishment of cardiopulmonary bypass before sternotomy in preparation for uncontrollable hemorrhage. Proximal aortic arch replacement with a branch to the right axillary artery was successfully performed using circulatory arrest and selective cerebral perfusion. Keywords: innominate artery, rupture, trauma

Introduction

Case Report

Traumatic injuries to the thoracic great vessels are rarely seen in clinical situations because it has been reported that the majority of patients with such injuries die before arrival at the hospital.1) Blunt traumatic injury to the innominate artery is relatively rare for the same reason, and various surgical strategies for its repair have been reported according to the individual situation. We describe a rare case of traumatic intimal transection of the innominate artery due to a fall, complicated by hemodynamic shock and disturbance of consciousness, which was successfully treated with proximal aortic arch replacement.

A 40-year-old woman who fell from a fourth-floor window was brought to our hospital by ambulance. Her peak blood pressure was 40 mmHg on arrival, and she was a transient responder to fluid resuscitation. The patient had some motor responses to pain but was not conscious (Glasgow Coma Scale [GCS] of 4); thus, neurological function could not be evaluated in detail. There were multiple lacerations on her body and extremities, and an open fracture was also seen on her left upper limb. Chest X-rays showed a widened superior mediastinum (Fig. 1), bilateral upper rib fractures, fractures of the sixth cerebral and second to fourth thoracic vertebral spinous processes, and a compression fracture of the third thoracic vertebral body. Enhanced computed tomography (CT) revealed a large hematoma in the superior mediastinum. Frontal CT image reconstruction suggested transection of the innominate artery near its origin (Fig. 2). Aortic dissection at either the ascending aorta or arch was equivocal. Although a brain CT did not show any apparent bleeding or damage, cerebral malperfusion was suspected because of her disturbance of

Department of Cardiovascular Surgery, Osaka City University Graduate School of Medicine, Osaka, Osaka, Japan Received: December 1, 2013; Accepted: March 14, 2014 Corresponding author: Yasuyuki Bito, MD, PhD. Department of Cardiovascular Surgery, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi, Abeno-ku, Osaka, Osaka 545-8585, Japan Tel: +81-6-6645-3980, Fax: +81-6-6646-3071 E-mail: [email protected]

Annals of Vascular Diseases Vol. 7, No. 2 (2014)

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Fig. 2 Fig. 1

Chest X-rays show a widened mediastinum and bilateral upper rib fractures.

consciousness. She was intubated and an emergency operation to treat the thoracic vascular injury was performed. At the beginning of the operation, prior to sternotomy, cardiopulmonary bypass (CPB) was established by cannulating the right femoral artery and vein. An 8-mm Dacron graft was anastomosed to the right axillary artery as another perfusion root. After bladder temperature was reduced to 30°C, a median sternotomy was performed. An additional drainage cannula was inserted to the superior vena cava for CPB. There was extensive hematoma in the upper mediastinum. The innominate artery was extremely enlarged around its origin, though the rupture was not apparent on its external membrane. The surface of the ascending aorta and the aortic arch was markedly darker in color, suggesting a problem in the aortic wall such as dissection. Because of the uncertainty regarding condition of the aorta, we opted not to place an aortic clamp. Therefore, under circulatory arrest with selective cerebral perfusion and a core bladder temperature of 26°C, the ascending aorta was opened without the application of a clamp. The selective cerebral perfusion was established by using the perfusion root on the right axillary artery and direct cannulation to the left carotid and subclavian artery. Cardiopledgic solution was supplied by retrograde root. There was broad adventitial hematoma on the ascending aorta to the aortic arch, but no dissection. A complete 166

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Frontal computed tomography image reconstruction suggests transection at the origin of the innominate artery (arrow).

circumferential intimal transection was seen at the root of the innominate artery. Because the distal portion of the innominate artery appeared too fragile to support an anastomosis, it was closed. Proximal aortic arch replacement was performed with a 20-mm Dacron prosthesis, creating the distal aortic anastomosis at a site just proximal to the left common carotid artery. Instead of reconstructing the closed innominate artery, a prosthetic branch to the right axillary artery was extended from the main graft (Fig. 3). During the postoperative period, the patient’s consciousness gradually recovered to clear but left hemiparesis remained persistently. Spinal cord injury was seen on magnetic resonance imaging. After placement of a tracheostomy for ventilatory support, the left arm fracture was also treated surgically. She was discharged to a rehabilitation facility on postoperative day 58.

Discussion Blunt traumatic injury of the innominate artery is uncommon. According to an autopsy study by Dosios, et al., 94.5% of victims with blunt trauma of the thoracic aorta and aortic arch branches die at the scene of the accident or during transportation. The majority of these injuries occur at the aortic isthmus; only 8.3% are to the aortic arch branches.1) The most frequently injured of the aortic arch branches is the Annals of Vascular Diseases Vol. 7, No. 2 (2014)

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Surgical Repair of Innominate Arterial Rupture (A)

Fig. 3

(B)

(A) An intimal transection existed at the root of the innominate artery, and the discolored surface was also seen from the ascending aorta to the aortic arch. (B) Proximal aortic replacement with a branch to the right axillary artery was performed.

innominate artery.2) The mechanism of trauma is considered to be maximum tension, mainly at the root of the innominate artery, caused by simultaneous neck hyperextension with rotation of the head and left displacement of the heart from anteroposterior compression of the chest. Thus, the proximal part of the innominate artery is the most common site of injury.3–5) Although this mechanism is induced by abrupt deceleration commonly seen in motor vehicle accidents, a similar mechanism was presumed to have been in effect upon our patient’s impact with the ground. Falls leading to innominate artery injury are extremely rare, representing only 0%–2.2% of traumatic thoracic arterial injuries.1,2,4) When the victim of blunt innominate artery injury can be brought to a medical facility, hemodynamic status is often fairly stable and hemorrhagic shock relatively rare, probably because hematoma and the surrounding tissue prevent devastating rupture. The mortality rate of these patients has improved to 0%–1.6% in recent years. Conversely, in cases like that of our patient, in which there is shock or central nervous system deficit on admission, the mortality rate increases to 41%–100%.4,6) In these critical cases, Annals of Vascular Diseases Vol. 7, No. 2 (2014)

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serious vascular injuries causing continuous bleeding and cephalic malperfusion may require prompt diagnosis and treatment. Innominate artery injury is usually suspected when a widened mediastinum is seen on chest X-ray or clinical features seen on examination. Definitive diagnosis has been considered to require aortography; however, shock precludes its use. The recent introduction of helical CT scanning provides precise vascular mapping, and additional angiography can be abbreviated so that rapid treatment can be performed for critical patients. Our patient was hemodynamically unstable and aortography was not performed; however, a reconstructed coronal-section image provided enough information to make an accurate diagnosis and permit an emergent operation. Various operative procedures have been reported previously, mainly according to the location and extent of injury. When injuries are located close to the origin of the innominate artery, bypass grafting from the ascending aorta to the distal part of innominate artery, with closure of the proximal stump, is preferred. This procedure usually requires partial aortic clamping for proximal anastomosis of the graft and for 167

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stump closure. For injuries to the mid region, interposition grafting can be performed. Resection and primary anastomosis can also be performed if the injury is not associated with extensive tissue loss or tension. Individual revascularization is occasionally required for the right subclavian and carotid arteries if the injuries are more distal.5) For such interposition or primary closure, simple clamping or temporary shunting of the innominate artery is performed. A minimum backflow pressure of 50 mmHg is considered to be required for cerebral protection.4) Although surgical treatments without the use of CPB have been performed in many cases, CPB with hypothermia and selective cerebral perfusion has been also reported to be useful in cases with extensive injury or uncontrollable hemorrhage.7,8) Our patient’s unstable hemodynamic status implied continuous bleeding that could be uncontrollable during our approach to the injured site. In addition, we preferred not to employ an aortic clamp in this case because of the uncertain condition of the aortic wall. Therefore, CPB was initiated and systemic temperature lowered for immediate induction of circulatory arrest prior to sternotomy. Moreover, cerebral perfusion with hypothermia using the right axillary artery was potentially useful because cephalic malperfusion was suspected. For cases as complicated as that of our patient, CPB offers a safe option for maintenance of hemodynamics, confirmation of the precise state of the injured vasculature, and safe repair. Endovascular treatments using stent grafts have recently been reported to be useful by some authors.9) Although less invasive and preferred for patients who cannot tolerate open surgery, endovascular stent grafting requires anatomical suitability such as sufficient landing zones and was not an appropriate treatment for the present case.

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Conclusions Traumatic innominate artery injury is rare and can be lethal in cases with hemodynamic shock and neurological deficit. CPB and circulatory arrest can be useful for surgical treatment in cases suspicious for uncontrollable bleeding or extensive vascular damage.

Disclosure Statement All authors have no conflicts of interest to report.

References 1) Dosios TJ, Salemis N, Angouras D, et al. Blunt and penetrating trauma of the thoracic aorta and aortic arch branches: an autopsy study. J Trauma 2000; 49: 696-703. 2) Rosenberg JM, Bredenberg CE, Marvasti MA, et al. Blunt injuries to the aortic arch vessels. Ann Thorac Surg 1989; 48: 508-13. 3) Graham JM, Feliciano DV, Mattox KL, et al. Innominate vascular injury. J Trauma 1982; 22: 647-55. 4) Hirose H, Gill IS. Blunt injury of the innominate artery: a case report and review of literature. Ann Thorac Cardiovasc Surg 2004; 10: 218-23. 5) Karmy-Jones R, DuBose R, King S. Traumatic rupture of the innominate artery. Eur J Cardiothorac Surg 2003; 23: 782-7. 6) Johnston RH, Wall MJ, Mattox KL. Innominate artery trauma: a thirty-year experience. J Vasc Surg 1993; 17: 134-9; discussion 139-40. 7) Anastasiadis K, Channon KM, Ratnatunga C. Traumatic innominate artery transection. J Cardiovasc Surg (Torino) 2002; 43: 697-700. 8) Veerasingam D, Vioreanu M, O’ Donohue M, et al. Traumatic transection of the innominate artery. Interact Cardiovasc Thorac Surg 2003; 2: 569-71. 9) Miles EJ, Blake A, Thompson W, et al. Endovascular repair of acute innominate artery injury due to blunt trauma. Am Surg 2003; 69: 155-9.

Annals of Vascular Diseases Vol. 7, No. 2 (2014)

2014/06/13 15:31

Successful surgical treatment of traumatic transection of the innominate artery: a case report.

Blunt traumatic injury to the innominate artery is relatively rare. We present the case of a 40-year-old woman who fell from a fourth-floor window and...
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