- Email: [email protected]
Endovascular Management of Blunt Aortic Injury With an Associated Aberrant Right Subclavian Artery: A Report of Three Cases
Endovascular Management of Blunt Aortic Injury With an Associated Aberrant Right Subclavian Artery: A Report of Three Cases Tyler S. Reynolds,1 Carlos E. Donayre,1 Carmelo Gastambide Somma,2 Walter Giossa Poggio,2 Karen M. Kim,1 Tien Nguyen,1 and Rodney White,1 Torrance, California and Montevideo, Uruguay
Traumatic rupture of the aorta in the rare setting of the aberrant right subclavian artery (ARSA) requires special consideration to prevent the occurrence of a devastating posterior cerebral circulation stroke. We present three cases managed by using an endovascular approach, with a discussion of important preoperative and operative issues. Three patients involved in motor vehicle collisions with multiple injuries were managed at two institutions. Computed tomography revealed transection of the aorta with incidental ARSA. All three cases were managed with a different approach. One patient did not undergo a preoperative bypass because imaging confirmed an adequate landing zone distal to the origin of the left subclavian artery. Two patients received preoperative right carotid-to-subclavian bypass for anticipated endograft coverage of both subclavian arteries to preserve single vertebral arterial flow. In one patient, an endovascular occlusion device was deployed in the ARSA before aortic endograft deployment. In the other, ARSA occlusion was performed 4 days later for a persistent type II endoleak. The patient who underwent bypass and preoperative ARSA occlusion suffered a fatal posterior circulation stroke shortly after surgery. The other two patients had no procedural complications and have not required any reinterventions at follow-up after 2 and 5 years. One patient is still undergoing rehabilitation after 5 years of follow-up for traumatic brain injury unrelated to the endograft repair. Although the incidence of ARSA is very low, preoperative imaging and assessment of cerebral blood flow are critical to prevent a perioperative stroke. Revascularization, if required to achieve a secure proximal landing zone, must be performed before endograft deployment. Bilateral subclavian revascularization is indicated if anomalies of the cerebral circulation are present.
INTRODUCTION Aortic transection occurs in only 0.8% of motor vehicle collisions but accounts for 16% of associated deaths.1 Endovascular management of these Presented at the 28th Annual Meeting of the Southern California Vascular Surgical Society, April 30 – May 1, 2010, Carlsbad, CA. 1 Division of Vascular and Endovascular Surgery, Department of Surgery, Harbor-UCLA Medical Center, Torrance, CA. 2 Asociacion Espa~ nola Primera de Socorros Mutuos, Montevideo, Uruguay.
Correspondence to: Carlos E. Donayre, MD, Division of Vascular and Endovascular Surgery, Harbor-UCLA Medical Center, 1000 West Carson Street, Torrance, CA 90502, USA, E-mail: [email protected] Ann Vasc Surg 2011; 25: 979.e7-979.12 DOI: 10.1016/j.avsg.2011.05.001 Ó Annals of Vascular Surgery Inc. Published online: July 18, 2011
injuries is rapidly evolving and may soon become first-line treatment for select patients. Sufficient landing zone to avoid a type I endoleak often requires coverage of the left subclavian artery. The absolute and relative indications for selective revascularization of the left subclavian artery are discussed. Aberrant right subclavian artery (ARSA), also referred to as arteria lusoria, is the most common intrathoracic arterial abnormality occurring in 0.45-2% of the population. The abnormality is often discovered incidentally on diagnostic imaging.2,3 To our knowledge, the endovascular management of transection of the thoracic aorta with ARSA has not been previously reported. In the special setting of an ARSA and a transected aorta, endograft coverage of both subclavian vessels mandates 979.e7
979.e8 Case reports
Annals of Vascular Surgery
revascularization of one or possibly both vessels. We report management of three such cases over a 5-year period at two different institutions. Case 1 A 21-year-old female asthmatic was struck laterally by a truck while she was in her vehicle. She was unconscious on arrival to the emergency room and was intubated for respiratory depression with a stable blood pressure. She had stigmata of facial and blunt chest trauma. Computed tomography (CT) showed a left maxillary and frontal skull fracture with hemorrhagic brain injury. CT of the thorax showed aortic injury, with a mediastinal hematoma and hemothorax (Fig. 1). An ARSA originating distal to the left subclavian artery was also noted. Transesophageal ultrasound confirmed an aortic intimal disruption with an associated pseudoaneurysm. The patient was initially stabilized in the intensive care unit and underwent thoracic endovascular aortic repair (TEVAR) the following day. A TALENT (Medtronic, Inc., Santa Rosa, CA), 26 mm in diameter and 150 mm in length, endoprosthesis was successfully deployed just distal to the origin of the left subclavian artery with exclusion of the transection and the ARSA. She subsequently underwent tracheostomy 5 days later, followed by gastrostomy, and was discharged 2 months after the incident with moderate neurologic impairment secondary to traumatic brain injury. At that time, a repeat CT showed no evidence of endoleak and successful endovascular exclusion of her transected aorta. CT scan at 1 and 5 years later confirmed the lack of endoleaks and no migration (Fig. 2). She is still undergoing neurologic rehabilitation while working as a secretary. Case 2 A 40-year-old man was driving a semi-truck when he struck another truck. After a 90-minute extrication, he was brought to a local emergency department in a hypotensive state with a blood pressure of 85/52 mm Hg and required intubation. Abdominal ultrasound demonstrated fluid in Morrison’s pouch. He was given 4 U of packed red blood cells and 4 U of fresh frozen plasma, and blood pressure was restored to normal. CT scan revealed an openbook pelvic fracture and a possible aortic injury. The patient was airlifted to our institution where CT angiogram confirmed aortic transection and ARSA. CT angiogram of the brain demonstrated questionable filling of the right posterior communicating artery of the circle of Willis; however, it was
Fig. 1. Thoracic aortic transection with aortic hematoma, left hemothorax, and aberrant right subclavian artery (ARSA).
Fig. 2. Postoperative computed tomographic reconstruction showing endograft in good position with a patent left subclavian artery and exclusion of the ARSA.
believed to be patent. The vertebral arteries were of good caliber. The patient was taken to the endovascular suite immediately where transesophageal ultrasound and intravascular ultrasound confirmed transection located just distal to the left subclavian origin. A right carotid to right axillary bypass was performed using an 8-mm polytetrafluoroethylene to preserve flow to the right vertebral artery. A 14 mm Amplatzer vascular plug (AGA Medical Corp., Minneapolis, MN) was then deployed in the proximal right subclavian artery (Fig. 3). A TALENT (Medtronic, Inc.), 32 mm in diameter, endoprosthesis was subsequently deployed excluding the right and left subclavian arteries. Adenosineinduced temporary cardiac arrest was performed to ensure proper placement of the endoprosthesis, and
Vol. 25, No. 7, October 2011
Fig. 3. Fluoroscopy demonstrating axillary to right common carotid artery bypass graft followed by Amplatzer vascular plug placement to exclude the ARSA.
postoperative angiogram confirmed good placement without endoleak. The patient was transferred back to the intensive care unit in stable condition; however, he began to require increased ventilator support 6 hours later and had decreased ocular reflexes. CT confirmed posterior stroke with massive cerebral edema and basilar artery thrombosis. The patient expired shortly thereafter.
Case reports 979.e9
Fig. 4. Angiogram demonstrating site of traumatic aortic transection with origin of associated aberrant right subclavian artery (ARSA) (white arrow). RCCA, right common carotid artery; LCCA, left common carotid artery; LSA, left subclavian artery.
then taken for repair of the diaphragmatic injury, with a plan to return later for occlusion of the proximal right subclavian artery. Repeat CT the next day confirmed persistent type II endoleak from retrograde filling of the ARSA, and the patient was taken on postoperative day 4 for endoluminal exclusion of the leak using a 12-mm Amplatzer vascular plug. The patient has done well 2 years later with no further interventions.
Case 3
DISCUSSION
A 47-year-old man involved in a motor vehicle collision was found to have multiple pelvic fractures, acute diaphragmatic hernia, and widened mediastinum. He was hemodynamically stable; however, CT confirmed aortic transection, and so the patient was transferred to our institution. CT angiogram revealed transection of the aorta with incidental ARSA. It also demonstrated an intact circle of Willis and normal vertebral arteries. The patient was taken directly to the operating room. Angiography revealed approximately 15 mm between the lowermost edge of the left common carotid and the beginning of the transaction and the aberrant vessel could also be visualized (Fig. 4). A right carotid to right axillary bypass using an 8-mm polytetrafluoroethylene was again performed followed by device deployment. A 36-mm Valiant endoprosthesis (Medtronic, Inc.) was selected. After full deployment of the thoracic endoprosthesis, IVUS interrogation and angiography revealed full endoprosthesis expansion and good placement just distal to the left common carotid artery. Type II endoleak was visualized from the ARSA, as expected (Fig. 5). Given the patient’s other injuries, he was
Endovascular repair may soon become the first-line treatment for transection of the aorta. Traumatic rupture of the aortic isthmus can occur with rapid deceleration or extreme shear forces after blunt chest trauma.4 Mechanisms include compression and blast forces, especially in the vertical or horizontal axis.5 Immediate death has been reported in >75% of cases.4-7 In an autopsy series of all postmortem examinations over a 4-year period, traumatic rupture of the aorta was found in 16% of automobile accidents resulting in death.6 This patient population is younger than those with other thoracic aortic pathology, including aneurysm and dissection. The pathology and characteristics of the aorta are quite different. Our institution has found the aorta in these younger patients to be more compliant than older patients (T. Reynolds et al., unpublished data, January 2011). This may be related to normal aging or a physiologic change after blunt aortic injury. In a prospective study of blunt aortic injury by the American Association for the Surgery of Trauma in 1996, the average time to open operative repair for transection was just over 16 hours.8 However, the
979.e10 Case reports
Annals of Vascular Surgery
minimal intimal disruption may be able to be managed with delayed treatment or nonoperative management. However, if the transection is complex (pseudoaneurysm, intra-aortic thrombus, or hemothorax), then it should be treated emergently. At this time, delayed repair may be a reasonable alternative in carefully selected patients with long-term follow-up and imaging.12,13 Serial radiographic examinations during the first week are necessary because of the potential for rapid progression of the aortic injury.14
Fig. 5. Final angiogram demonstrating type II endoleak secondary to retrograde filling through ARSA.
average time taken to perform an endovascular repair at our institution is less than 16 hours. In the same study, reported mortality rate with open repair is 14.9-15.1%, depending on technique. In an analysis by Tang et al. in 2008, endovascular repair was compared with open surgery.9 Mortality rate is lower with endovascular repair at 7.6 versus 15.2%. Paraplegia rate was reported to be 0% with endovascular repair and 5.6% for open repair. Stroke is also lower at 0.8 versus 5.6%. A later study by the American Association for the Surgery of Trauma in 2008 showed similar rates of paraplegia in both groups, and additionally reported device-related complications, including vascular access (4.8%) and endoleak (13.6%).10 Endovascular management of aortic transection has been shown to be safe and effective in clinical trials. The evolution of management of blunt aortic injury is well summarized by Neschis et al. in 2008.11 Several advantages of endovascular repair include decreased blood loss, operative time, hospital stay, and most importantly, aortic clamping is not necessary; therefore, risks associated with shunting and bypass are avoided. Perioperative mortality is decreased with endovascular repair at 6.8% compared with 16-31% for open repair. Stroke and paraplegia rates have been shown to be lower with endovascular repair when compared with open repair.11 Anticoagulants are routinely administered during stent-graft deployment. Systemic heparinization is avoided in the setting of complex solid organ injury, concern for head trauma/brain injury, or significant pelvic fractures. In such cases, we connect only access sheaths to a heparin solution to prevent formation of thrombus within the sheaths. The previously published data are limited in regard to the timing of repair of aortic transection. Patients without pseudoaneurysm formation and
Subclavian Artery Revascularization Controversy exists regarding routine or selective revascularization with the coverage of one subclavian (left) artery during TEVAR without ARSA. Selective revascularization, through carotid-to-subclavian bypass or transposition of the subclavian artery, for patients with unfavorable anatomy has been shown to be safe. Reece et al. reported on 27 patients who underwent TEVAR requiring coverage of the left subclavian artery (LSA) among 64 patients in the series.15 Seven patients underwent selective preoperative revascularization based on vascular anatomy. The indications for TEVAR for these patients were not mentioned; however, indications for preemptive revascularization included dominant left vertebral artery (one patient), incomplete Circle of Willis (two patients), ARSA (three patients), and left internal mammary artery-to-left anterior descending artery bypass (one patient). The three patients with ARSA underwent revascularization 1-3 days before TEVAR. Among the 20 patients who were not revascularized, three developed left arm claudication and one developed postoperative retrograde aortic dissection and subclavian steal syndrome. All four patients subsequently underwent postoperative LSA revascularization with no further symptoms. There was no perioperative mortality or paraplegia in the series and no significant posterior circulation strokes or permanent left arm deficits. In a single-institution study by Botta et al. in 2008, management of the left subclavian artery was addressed.7 Of 27 patients who underwent endovascular repair for acute traumatic transection of the descending aorta, eight had an aorta with a short proximal neck (<5 mm), and four of these patients underwent endovascular complete or partial LSA coverage. The other four patients had pseudoaneurysm of the left subclavian or left carotid artery and were treated with conventional open intervention. A single patient with LSA coverage suffered a large cerebellar stroke despite the absence of any alteration of the circle of Willis. The
Vol. 25, No. 7, October 2011
properties of the vertebral arteries on preoperative imaging, namely dominance, are not reported. Riesenman et al. reported outcomes of 28 of 112 patients who underwent complete or partial coverage of the left subclavian artery.16 Debranching was performed for zone 0 or 1 coverage. Three of these patients underwent carotid-to-carotid bypass and one of these underwent left carotid-to-subclavian bypass for right vertebral artery stenosis. One patient who did not undergo revascularization developed positional claudication of the left hand while turning his head. Fourteen of 24 patients who underwent zone 2 placement had complete coverage of the left subclavian artery. Three patients developed left upper extremity symptoms but did not require intervention. One patient who had been treated emergently for a ruptured mycotic aneurysm developed rest pain requiring revascularization was found to have aberrant insertion and coverage of a left vertebral artery. Three embolic strokes were reported (12.5%), but none were attributed to vertebral-basilar insufficiency ischemia. The authors concluded that prophylactic revascularization is not necessary. Options for maintaining subclavian artery patency during TEVAR include carotid-to-subclavian bypass or transposition, as well as endovascular techniques including fenestrated and branched grafts, and the ‘‘chimney procedure.’’17 The ‘‘chimney (snorkel) procedure’’ may be performed to improve forward flow through the subclavian artery with the placement of a subclavian stent at the orifice of the subclavian artery. This allows extension of the aortic endograft over a portion of the subclavian artery. The anatomy must be favorable, including an adequate neck distal to the left subclavian to minimize risk of a type I endoleak around the subclavian stent. Aberrant Right Subclavian Artery The ARSA results from a developmental abnormality likely related to regression of the right fourth aortic arch and persistence of the distal right dorsal aorta. It usually travels posterior to the esophagus and is usually asymptomatic. Less than 10% of patients develop dysphagia lusoria and the origin can become aneurysmal in 8% of patients (Kommerell’s Diverticulum).3,18 Other abnormalities commonly seen with this anomaly include a nonrecurrent right inferior laryngeal nerve, a common origin of the common carotid arteries, a replaced right or left vertebral artery, coarctation of the aorta, a rightsided thoracic duct, and a dextroposed aortic arch.18 Symptoms of progressive dysphagia or aneurysmal disease prompt surgical intervention.
Case reports 979.e11
There are several case reports in the previously published data describing surgical repair of symptomatic ARSA as well as special considerations in the repair of type B dissection.19-22 Traumatic rupture of an ARSA has also been reported.23 Bednarkiewicz et al. emphasized the importance of preoperative diagnosis of ARSA in a patient with blunt aortic injury treated by open surgical approach.24 Clamping of the aorta proximal to both subclavian arteries with inadvertent exclusion of both vertebral arteries may lead to posterior circulation ischemia. Revascularization is the mainstay of therapy. We prefer right carotid-to-axillary bypass initially because it eliminates the risk of aneurysm formation later in the ARSA, similar to what happens with the persistent sciatic artery. However, if the left vertebral artery is dominant, a left carotid-to-subclavian/ axillary bypass is indicated.
CONCLUSION The devastating complications emphasize the importance of careful preoperative planning. The CT angiogram is essential in all patients not only to characterize the nature of the aortic injury and associated injuries in the stable trauma patient, but also to detect any pertinent anomaly such as the ARSA. A widened mediastinum on plain chest film and transesophageal echocardiogram alone are not sensitive for detection of ARSA. Failure to recognize the surgical and clinical ramifications can have drastic consequences. Carotidto-subclavian arterial bypass before endograft exclusion of the vertebral arteries has been shown to successfully maintain posterior circulatory flow through the vertebral artery. The following principles are emphasized from the cases discussed. First, preoperative CT angiography or aortography is vital to assess aortic anatomy, vertebral-basilar system, and cerebral vasculature. Second, forward flow must be maintained through the vertebral-basilar system to maintain posterior cerebral perfusion. Indications for revascularization include incomplete circle of Willis, exclusion of a dominant vertebral artery, presence of internal mammary coronary artery bypass, and ipsilateral functioning hemodialysis access. Relative indications also include extensive aortic coverage, previous abdominal aortic aneurysm repair, and aberrant left vertebral artery. The landing zone is often proximal to both subclavian arteries in the patient with ARSA. In this setting, a unilateral revascularization procedure is absolutely necessary to maintain perfusion of the posterior circulation of the brain. Selective bilateral
979.e12 Case reports
revascularization in the setting of ARSA is then indicated in the special settings discussed. Bilateral revascularization is recommended in the setting of incomplete Circle of Willis. In case 2, flow in the right posterior communicating artery of the circle of Willis was questionable. A left carotidto-subclavian or axillary bypass, subclavian-carotid transposition, or endovascular technique, including the ‘‘Chimney procedure,’’ are options for revascularization.17 If both vertebral arteries need to be revascularized, we prefer right carotid-to-subclavian/axillary artery bypass and a ‘‘chimney’’ procedure to maintain perfusion of the left vertebral artery. Third, if revascularization is necessary, it must be performed before endoluminal exclusion to preserve flow through the vertebral-basilar system. Carotid artery to axillary bypass is a rapid revascularization procedure and is preferred by some surgeons in the setting of aortic transection. Finally, the need for occlusion of the native ARSA in the setting of type II endoleak is not urgent because associated morbidity is low. In fact, acute changes in perfusion through the vertebral arteries may be detrimental. The anticipated type II endoleak in case 3 was occluded 4 days later with no complications. In conclusion, traumatic rupture of the aorta with ARSA can be managed successfully with an endovascular approach. As endovascular repair continues to replace open repair as first-line treatment for most patients, thorough preoperative planning will improve outcomes and assist in the development of innovative techniques for complicated patients.
REFERENCES 1. Jahromi A, Kazemi K, Safar H, Doobay B, Cina C. Traumatic rupture of the thoracic aorta: cohort study and systematic review. J Vasc Surg 2001;34:1029-1034. 2. Felson B, Cohen S, Courter S, McGuire J. Anomalous right subclavian artery. Radiology 1950;54:340-349. 3. Freed K, Low V. The aberrant subclavian artery. Am J Roentgenol 1997;166:481-484. 4. Sevitt S. The mechanism of traumatic rupture of the thoracic aorta. Br J Surg 1977;64:166-173. 5. Parmley LF, Mattingly TW, Mariom WC, Jahnke EJ. Nonpenetrating traumatic injury of the aorta. Circulation 1958;17: 1086-1101. 6. Greendyke RM. Traumatic rupture of aorta. Special reference to automobile accidents. JAMA 1996;195:119-122. 7. Botta L, Russo V, Savini C, et al. Endovascular treatment for acute traumatic transaction of the descending aorta: focus on operative timing and left subclavian artery management. J Thorac Cardiovasc Surg 2008;136:1558-1563.
Annals of Vascular Surgery
8. Fabian T, Richardson J, Croce M, et al. Prospective study of blunt aortic injury: multicenter trial of the American Association for the Surgery of Trauma. J Trauma 1997;42: 374-383. 9. Tang G, Tehrani H, Usman A, Katariya K, Otero C, Perez E, Eskandari M. Reduced mortality, paraplegia, and stroke with stent graft repair of blunt aortic transections: a modern meta-analysis. J Vasc Surg 2008;47:671-675. 10. Demetriades D, Velmahos G, Scalea T, et al. Diagnosis and treatment of blunt thoracic aortic injuries: changing perspectives. J Trauma 2008;64:1415-1419. 11. Neschis D, Scalea T, Flinn W, Griffith B. Blunt aortic injury. N Engl J Med 2008;359:1708-1716. 12. Cafarelli A, Mallidi H, Maggio P, Spain D, Miller D, Mitchell S. Early outcomes of deliberate nonoperative management for blunt thoracic aortic injury in trauma. J Thorac Cardiovasc Surg 2010;140:598-605. 13. Symbas P, Sherman A, Silver J, Symbas J, Lackey J. Traumatic rupture of the aorta: immediate or delayed repair? Ann Vasc 2002;235:796-802. 14. Holmes J, Bloch R, Hall A, Carter Y, Karmy-Jones R. Natural history of traumatic rupture of the thoracic aorta managed nonoperatively: a longitudinal analysis. Ann Thorac Surg 2002;73:1149-1154. 15. Reece B, Gazoni L, Cherry K, et al. Re-evaluating the need for left subclavian artery revascularization with thoracic endovascular aortic repair. Ann Thorac Surg 2007;84: 1201-1205. 16. Riesenman P, Farber M, Mendes R, Marston W, Fulton J, Keagy B. Coverage of the left subclavian artery during thoracic endovascular aortic repair. J Vasc Surg 2007;45:90-95. 17. Criado F. A percutaneous technique for preservation of arch branch patency during thoracic endovascular aortic repair (TEVAR): retrograde catheterization and stenting. J Encovasc Ther 2007;14:54-58. 18. Epstein D, Debord J. Abnormalities associated with aberrant right subclavian arteries-a case report. Vasc Endovascular Surg 2002;36:297-303. 19. Weinberger G, Randall A, Parker B, Kiefer A. Involvement of an aberrant right subclavian artery in dissection of the thoracic aorta: diagnostic and therapeutic implication. Am J Roentgenol 1977;129:653-655. 20. Mosquera V, Marini M, Rodriguez F, Cao I, Juffe A. Complicated acute type B aortic dissection with involvement of an aberrant right subclavian artery and rupture of a thoracoabdominal aortic aneurysm, Crawford type I: successful emergency endovascular treatment. J Thorac Cardiovasc Surg 2007;134:1055-1057. 21. Baccin C, Montegegro M, Mour~ao G. Thoracic aorta dissection associated with aberrant right subclavian artery: treatment with endovascular stent-graft placement. Yale J Biol Med 2004;77:59-62. 22. Syme J. Aortic dissection involving an aberrant right subclavian artery studied by aortography. Aust Radiol 1973;17:174-179. 23. Alcocer J, Spier L, Dyke C, Griffith B, Gammie J. Traumatic rupture of an aberrant right subclavian artery. Ann Thorac Surg 2000;69:621-623. 24. Bednarkiewicz M, Robert J, Khatchatourian G, Genin G, Irmay F, Faidutti B. Traumatic rupture of the aortic isthmus in a patient with an aberrant right subclavian artery: therapeutic implications. J Thorac Cardiovasc Surg 1999;118:1112-1113.
Traumatic rupture of the aorta in the rare setting of the aberrant right subclavian artery (ARSA) requires special consideration to prevent the occurrence of a devastating posterior cerebral circulation stroke. We present three cases managed by using an endovascular approach, with a discussion of important preoperative and operative issues. Three patients involved in motor vehicle collisions with multiple injuries were managed at two institutions. Computed tomography revealed transection of the aorta with incidental ARSA. All three cases were managed with a different approach. One patient did not undergo a preoperative bypass because imaging confirmed an adequate landing zone distal to the origin of the left subclavian artery. Two patients received preoperative right carotid-to-subclavian bypass for anticipated endograft coverage of both subclavian arteries to preserve single vertebral arterial flow. In one patient, an endovascular occlusion device was deployed in the ARSA before aortic endograft deployment. In the other, ARSA occlusion was performed 4 days later for a persistent type II endoleak. The patient who underwent bypass and preoperative ARSA occlusion suffered a fatal posterior circulation stroke shortly after surgery. The other two patients had no procedural complications and have not required any reinterventions at follow-up after 2 and 5 years. One patient is still undergoing rehabilitation after 5 years of follow-up for traumatic brain injury unrelated to the endograft repair. Although the incidence of ARSA is very low, preoperative imaging and assessment of cerebral blood flow are critical to prevent a perioperative stroke. Revascularization, if required to achieve a secure proximal landing zone, must be performed before endograft deployment. Bilateral subclavian revascularization is indicated if anomalies of the cerebral circulation are present.
INTRODUCTION Aortic transection occurs in only 0.8% of motor vehicle collisions but accounts for 16% of associated deaths.1 Endovascular management of these Presented at the 28th Annual Meeting of the Southern California Vascular Surgical Society, April 30 – May 1, 2010, Carlsbad, CA. 1 Division of Vascular and Endovascular Surgery, Department of Surgery, Harbor-UCLA Medical Center, Torrance, CA. 2 Asociacion Espa~ nola Primera de Socorros Mutuos, Montevideo, Uruguay.
Correspondence to: Carlos E. Donayre, MD, Division of Vascular and Endovascular Surgery, Harbor-UCLA Medical Center, 1000 West Carson Street, Torrance, CA 90502, USA, E-mail: [email protected] Ann Vasc Surg 2011; 25: 979.e7-979.12 DOI: 10.1016/j.avsg.2011.05.001 Ó Annals of Vascular Surgery Inc. Published online: July 18, 2011
injuries is rapidly evolving and may soon become first-line treatment for select patients. Sufficient landing zone to avoid a type I endoleak often requires coverage of the left subclavian artery. The absolute and relative indications for selective revascularization of the left subclavian artery are discussed. Aberrant right subclavian artery (ARSA), also referred to as arteria lusoria, is the most common intrathoracic arterial abnormality occurring in 0.45-2% of the population. The abnormality is often discovered incidentally on diagnostic imaging.2,3 To our knowledge, the endovascular management of transection of the thoracic aorta with ARSA has not been previously reported. In the special setting of an ARSA and a transected aorta, endograft coverage of both subclavian vessels mandates 979.e7
979.e8 Case reports
Annals of Vascular Surgery
revascularization of one or possibly both vessels. We report management of three such cases over a 5-year period at two different institutions. Case 1 A 21-year-old female asthmatic was struck laterally by a truck while she was in her vehicle. She was unconscious on arrival to the emergency room and was intubated for respiratory depression with a stable blood pressure. She had stigmata of facial and blunt chest trauma. Computed tomography (CT) showed a left maxillary and frontal skull fracture with hemorrhagic brain injury. CT of the thorax showed aortic injury, with a mediastinal hematoma and hemothorax (Fig. 1). An ARSA originating distal to the left subclavian artery was also noted. Transesophageal ultrasound confirmed an aortic intimal disruption with an associated pseudoaneurysm. The patient was initially stabilized in the intensive care unit and underwent thoracic endovascular aortic repair (TEVAR) the following day. A TALENT (Medtronic, Inc., Santa Rosa, CA), 26 mm in diameter and 150 mm in length, endoprosthesis was successfully deployed just distal to the origin of the left subclavian artery with exclusion of the transection and the ARSA. She subsequently underwent tracheostomy 5 days later, followed by gastrostomy, and was discharged 2 months after the incident with moderate neurologic impairment secondary to traumatic brain injury. At that time, a repeat CT showed no evidence of endoleak and successful endovascular exclusion of her transected aorta. CT scan at 1 and 5 years later confirmed the lack of endoleaks and no migration (Fig. 2). She is still undergoing neurologic rehabilitation while working as a secretary. Case 2 A 40-year-old man was driving a semi-truck when he struck another truck. After a 90-minute extrication, he was brought to a local emergency department in a hypotensive state with a blood pressure of 85/52 mm Hg and required intubation. Abdominal ultrasound demonstrated fluid in Morrison’s pouch. He was given 4 U of packed red blood cells and 4 U of fresh frozen plasma, and blood pressure was restored to normal. CT scan revealed an openbook pelvic fracture and a possible aortic injury. The patient was airlifted to our institution where CT angiogram confirmed aortic transection and ARSA. CT angiogram of the brain demonstrated questionable filling of the right posterior communicating artery of the circle of Willis; however, it was
Fig. 1. Thoracic aortic transection with aortic hematoma, left hemothorax, and aberrant right subclavian artery (ARSA).
Fig. 2. Postoperative computed tomographic reconstruction showing endograft in good position with a patent left subclavian artery and exclusion of the ARSA.
believed to be patent. The vertebral arteries were of good caliber. The patient was taken to the endovascular suite immediately where transesophageal ultrasound and intravascular ultrasound confirmed transection located just distal to the left subclavian origin. A right carotid to right axillary bypass was performed using an 8-mm polytetrafluoroethylene to preserve flow to the right vertebral artery. A 14 mm Amplatzer vascular plug (AGA Medical Corp., Minneapolis, MN) was then deployed in the proximal right subclavian artery (Fig. 3). A TALENT (Medtronic, Inc.), 32 mm in diameter, endoprosthesis was subsequently deployed excluding the right and left subclavian arteries. Adenosineinduced temporary cardiac arrest was performed to ensure proper placement of the endoprosthesis, and
Vol. 25, No. 7, October 2011
Fig. 3. Fluoroscopy demonstrating axillary to right common carotid artery bypass graft followed by Amplatzer vascular plug placement to exclude the ARSA.
postoperative angiogram confirmed good placement without endoleak. The patient was transferred back to the intensive care unit in stable condition; however, he began to require increased ventilator support 6 hours later and had decreased ocular reflexes. CT confirmed posterior stroke with massive cerebral edema and basilar artery thrombosis. The patient expired shortly thereafter.
Case reports 979.e9
Fig. 4. Angiogram demonstrating site of traumatic aortic transection with origin of associated aberrant right subclavian artery (ARSA) (white arrow). RCCA, right common carotid artery; LCCA, left common carotid artery; LSA, left subclavian artery.
then taken for repair of the diaphragmatic injury, with a plan to return later for occlusion of the proximal right subclavian artery. Repeat CT the next day confirmed persistent type II endoleak from retrograde filling of the ARSA, and the patient was taken on postoperative day 4 for endoluminal exclusion of the leak using a 12-mm Amplatzer vascular plug. The patient has done well 2 years later with no further interventions.
Case 3
DISCUSSION
A 47-year-old man involved in a motor vehicle collision was found to have multiple pelvic fractures, acute diaphragmatic hernia, and widened mediastinum. He was hemodynamically stable; however, CT confirmed aortic transection, and so the patient was transferred to our institution. CT angiogram revealed transection of the aorta with incidental ARSA. It also demonstrated an intact circle of Willis and normal vertebral arteries. The patient was taken directly to the operating room. Angiography revealed approximately 15 mm between the lowermost edge of the left common carotid and the beginning of the transaction and the aberrant vessel could also be visualized (Fig. 4). A right carotid to right axillary bypass using an 8-mm polytetrafluoroethylene was again performed followed by device deployment. A 36-mm Valiant endoprosthesis (Medtronic, Inc.) was selected. After full deployment of the thoracic endoprosthesis, IVUS interrogation and angiography revealed full endoprosthesis expansion and good placement just distal to the left common carotid artery. Type II endoleak was visualized from the ARSA, as expected (Fig. 5). Given the patient’s other injuries, he was
Endovascular repair may soon become the first-line treatment for transection of the aorta. Traumatic rupture of the aortic isthmus can occur with rapid deceleration or extreme shear forces after blunt chest trauma.4 Mechanisms include compression and blast forces, especially in the vertical or horizontal axis.5 Immediate death has been reported in >75% of cases.4-7 In an autopsy series of all postmortem examinations over a 4-year period, traumatic rupture of the aorta was found in 16% of automobile accidents resulting in death.6 This patient population is younger than those with other thoracic aortic pathology, including aneurysm and dissection. The pathology and characteristics of the aorta are quite different. Our institution has found the aorta in these younger patients to be more compliant than older patients (T. Reynolds et al., unpublished data, January 2011). This may be related to normal aging or a physiologic change after blunt aortic injury. In a prospective study of blunt aortic injury by the American Association for the Surgery of Trauma in 1996, the average time to open operative repair for transection was just over 16 hours.8 However, the
979.e10 Case reports
Annals of Vascular Surgery
minimal intimal disruption may be able to be managed with delayed treatment or nonoperative management. However, if the transection is complex (pseudoaneurysm, intra-aortic thrombus, or hemothorax), then it should be treated emergently. At this time, delayed repair may be a reasonable alternative in carefully selected patients with long-term follow-up and imaging.12,13 Serial radiographic examinations during the first week are necessary because of the potential for rapid progression of the aortic injury.14
Fig. 5. Final angiogram demonstrating type II endoleak secondary to retrograde filling through ARSA.
average time taken to perform an endovascular repair at our institution is less than 16 hours. In the same study, reported mortality rate with open repair is 14.9-15.1%, depending on technique. In an analysis by Tang et al. in 2008, endovascular repair was compared with open surgery.9 Mortality rate is lower with endovascular repair at 7.6 versus 15.2%. Paraplegia rate was reported to be 0% with endovascular repair and 5.6% for open repair. Stroke is also lower at 0.8 versus 5.6%. A later study by the American Association for the Surgery of Trauma in 2008 showed similar rates of paraplegia in both groups, and additionally reported device-related complications, including vascular access (4.8%) and endoleak (13.6%).10 Endovascular management of aortic transection has been shown to be safe and effective in clinical trials. The evolution of management of blunt aortic injury is well summarized by Neschis et al. in 2008.11 Several advantages of endovascular repair include decreased blood loss, operative time, hospital stay, and most importantly, aortic clamping is not necessary; therefore, risks associated with shunting and bypass are avoided. Perioperative mortality is decreased with endovascular repair at 6.8% compared with 16-31% for open repair. Stroke and paraplegia rates have been shown to be lower with endovascular repair when compared with open repair.11 Anticoagulants are routinely administered during stent-graft deployment. Systemic heparinization is avoided in the setting of complex solid organ injury, concern for head trauma/brain injury, or significant pelvic fractures. In such cases, we connect only access sheaths to a heparin solution to prevent formation of thrombus within the sheaths. The previously published data are limited in regard to the timing of repair of aortic transection. Patients without pseudoaneurysm formation and
Subclavian Artery Revascularization Controversy exists regarding routine or selective revascularization with the coverage of one subclavian (left) artery during TEVAR without ARSA. Selective revascularization, through carotid-to-subclavian bypass or transposition of the subclavian artery, for patients with unfavorable anatomy has been shown to be safe. Reece et al. reported on 27 patients who underwent TEVAR requiring coverage of the left subclavian artery (LSA) among 64 patients in the series.15 Seven patients underwent selective preoperative revascularization based on vascular anatomy. The indications for TEVAR for these patients were not mentioned; however, indications for preemptive revascularization included dominant left vertebral artery (one patient), incomplete Circle of Willis (two patients), ARSA (three patients), and left internal mammary artery-to-left anterior descending artery bypass (one patient). The three patients with ARSA underwent revascularization 1-3 days before TEVAR. Among the 20 patients who were not revascularized, three developed left arm claudication and one developed postoperative retrograde aortic dissection and subclavian steal syndrome. All four patients subsequently underwent postoperative LSA revascularization with no further symptoms. There was no perioperative mortality or paraplegia in the series and no significant posterior circulation strokes or permanent left arm deficits. In a single-institution study by Botta et al. in 2008, management of the left subclavian artery was addressed.7 Of 27 patients who underwent endovascular repair for acute traumatic transection of the descending aorta, eight had an aorta with a short proximal neck (<5 mm), and four of these patients underwent endovascular complete or partial LSA coverage. The other four patients had pseudoaneurysm of the left subclavian or left carotid artery and were treated with conventional open intervention. A single patient with LSA coverage suffered a large cerebellar stroke despite the absence of any alteration of the circle of Willis. The
Vol. 25, No. 7, October 2011
properties of the vertebral arteries on preoperative imaging, namely dominance, are not reported. Riesenman et al. reported outcomes of 28 of 112 patients who underwent complete or partial coverage of the left subclavian artery.16 Debranching was performed for zone 0 or 1 coverage. Three of these patients underwent carotid-to-carotid bypass and one of these underwent left carotid-to-subclavian bypass for right vertebral artery stenosis. One patient who did not undergo revascularization developed positional claudication of the left hand while turning his head. Fourteen of 24 patients who underwent zone 2 placement had complete coverage of the left subclavian artery. Three patients developed left upper extremity symptoms but did not require intervention. One patient who had been treated emergently for a ruptured mycotic aneurysm developed rest pain requiring revascularization was found to have aberrant insertion and coverage of a left vertebral artery. Three embolic strokes were reported (12.5%), but none were attributed to vertebral-basilar insufficiency ischemia. The authors concluded that prophylactic revascularization is not necessary. Options for maintaining subclavian artery patency during TEVAR include carotid-to-subclavian bypass or transposition, as well as endovascular techniques including fenestrated and branched grafts, and the ‘‘chimney procedure.’’17 The ‘‘chimney (snorkel) procedure’’ may be performed to improve forward flow through the subclavian artery with the placement of a subclavian stent at the orifice of the subclavian artery. This allows extension of the aortic endograft over a portion of the subclavian artery. The anatomy must be favorable, including an adequate neck distal to the left subclavian to minimize risk of a type I endoleak around the subclavian stent. Aberrant Right Subclavian Artery The ARSA results from a developmental abnormality likely related to regression of the right fourth aortic arch and persistence of the distal right dorsal aorta. It usually travels posterior to the esophagus and is usually asymptomatic. Less than 10% of patients develop dysphagia lusoria and the origin can become aneurysmal in 8% of patients (Kommerell’s Diverticulum).3,18 Other abnormalities commonly seen with this anomaly include a nonrecurrent right inferior laryngeal nerve, a common origin of the common carotid arteries, a replaced right or left vertebral artery, coarctation of the aorta, a rightsided thoracic duct, and a dextroposed aortic arch.18 Symptoms of progressive dysphagia or aneurysmal disease prompt surgical intervention.
Case reports 979.e11
There are several case reports in the previously published data describing surgical repair of symptomatic ARSA as well as special considerations in the repair of type B dissection.19-22 Traumatic rupture of an ARSA has also been reported.23 Bednarkiewicz et al. emphasized the importance of preoperative diagnosis of ARSA in a patient with blunt aortic injury treated by open surgical approach.24 Clamping of the aorta proximal to both subclavian arteries with inadvertent exclusion of both vertebral arteries may lead to posterior circulation ischemia. Revascularization is the mainstay of therapy. We prefer right carotid-to-axillary bypass initially because it eliminates the risk of aneurysm formation later in the ARSA, similar to what happens with the persistent sciatic artery. However, if the left vertebral artery is dominant, a left carotid-to-subclavian/ axillary bypass is indicated.
CONCLUSION The devastating complications emphasize the importance of careful preoperative planning. The CT angiogram is essential in all patients not only to characterize the nature of the aortic injury and associated injuries in the stable trauma patient, but also to detect any pertinent anomaly such as the ARSA. A widened mediastinum on plain chest film and transesophageal echocardiogram alone are not sensitive for detection of ARSA. Failure to recognize the surgical and clinical ramifications can have drastic consequences. Carotidto-subclavian arterial bypass before endograft exclusion of the vertebral arteries has been shown to successfully maintain posterior circulatory flow through the vertebral artery. The following principles are emphasized from the cases discussed. First, preoperative CT angiography or aortography is vital to assess aortic anatomy, vertebral-basilar system, and cerebral vasculature. Second, forward flow must be maintained through the vertebral-basilar system to maintain posterior cerebral perfusion. Indications for revascularization include incomplete circle of Willis, exclusion of a dominant vertebral artery, presence of internal mammary coronary artery bypass, and ipsilateral functioning hemodialysis access. Relative indications also include extensive aortic coverage, previous abdominal aortic aneurysm repair, and aberrant left vertebral artery. The landing zone is often proximal to both subclavian arteries in the patient with ARSA. In this setting, a unilateral revascularization procedure is absolutely necessary to maintain perfusion of the posterior circulation of the brain. Selective bilateral
979.e12 Case reports
revascularization in the setting of ARSA is then indicated in the special settings discussed. Bilateral revascularization is recommended in the setting of incomplete Circle of Willis. In case 2, flow in the right posterior communicating artery of the circle of Willis was questionable. A left carotidto-subclavian or axillary bypass, subclavian-carotid transposition, or endovascular technique, including the ‘‘Chimney procedure,’’ are options for revascularization.17 If both vertebral arteries need to be revascularized, we prefer right carotid-to-subclavian/axillary artery bypass and a ‘‘chimney’’ procedure to maintain perfusion of the left vertebral artery. Third, if revascularization is necessary, it must be performed before endoluminal exclusion to preserve flow through the vertebral-basilar system. Carotid artery to axillary bypass is a rapid revascularization procedure and is preferred by some surgeons in the setting of aortic transection. Finally, the need for occlusion of the native ARSA in the setting of type II endoleak is not urgent because associated morbidity is low. In fact, acute changes in perfusion through the vertebral arteries may be detrimental. The anticipated type II endoleak in case 3 was occluded 4 days later with no complications. In conclusion, traumatic rupture of the aorta with ARSA can be managed successfully with an endovascular approach. As endovascular repair continues to replace open repair as first-line treatment for most patients, thorough preoperative planning will improve outcomes and assist in the development of innovative techniques for complicated patients.
REFERENCES 1. Jahromi A, Kazemi K, Safar H, Doobay B, Cina C. Traumatic rupture of the thoracic aorta: cohort study and systematic review. J Vasc Surg 2001;34:1029-1034. 2. Felson B, Cohen S, Courter S, McGuire J. Anomalous right subclavian artery. Radiology 1950;54:340-349. 3. Freed K, Low V. The aberrant subclavian artery. Am J Roentgenol 1997;166:481-484. 4. Sevitt S. The mechanism of traumatic rupture of the thoracic aorta. Br J Surg 1977;64:166-173. 5. Parmley LF, Mattingly TW, Mariom WC, Jahnke EJ. Nonpenetrating traumatic injury of the aorta. Circulation 1958;17: 1086-1101. 6. Greendyke RM. Traumatic rupture of aorta. Special reference to automobile accidents. JAMA 1996;195:119-122. 7. Botta L, Russo V, Savini C, et al. Endovascular treatment for acute traumatic transaction of the descending aorta: focus on operative timing and left subclavian artery management. J Thorac Cardiovasc Surg 2008;136:1558-1563.
Annals of Vascular Surgery
8. Fabian T, Richardson J, Croce M, et al. Prospective study of blunt aortic injury: multicenter trial of the American Association for the Surgery of Trauma. J Trauma 1997;42: 374-383. 9. Tang G, Tehrani H, Usman A, Katariya K, Otero C, Perez E, Eskandari M. Reduced mortality, paraplegia, and stroke with stent graft repair of blunt aortic transections: a modern meta-analysis. J Vasc Surg 2008;47:671-675. 10. Demetriades D, Velmahos G, Scalea T, et al. Diagnosis and treatment of blunt thoracic aortic injuries: changing perspectives. J Trauma 2008;64:1415-1419. 11. Neschis D, Scalea T, Flinn W, Griffith B. Blunt aortic injury. N Engl J Med 2008;359:1708-1716. 12. Cafarelli A, Mallidi H, Maggio P, Spain D, Miller D, Mitchell S. Early outcomes of deliberate nonoperative management for blunt thoracic aortic injury in trauma. J Thorac Cardiovasc Surg 2010;140:598-605. 13. Symbas P, Sherman A, Silver J, Symbas J, Lackey J. Traumatic rupture of the aorta: immediate or delayed repair? Ann Vasc 2002;235:796-802. 14. Holmes J, Bloch R, Hall A, Carter Y, Karmy-Jones R. Natural history of traumatic rupture of the thoracic aorta managed nonoperatively: a longitudinal analysis. Ann Thorac Surg 2002;73:1149-1154. 15. Reece B, Gazoni L, Cherry K, et al. Re-evaluating the need for left subclavian artery revascularization with thoracic endovascular aortic repair. Ann Thorac Surg 2007;84: 1201-1205. 16. Riesenman P, Farber M, Mendes R, Marston W, Fulton J, Keagy B. Coverage of the left subclavian artery during thoracic endovascular aortic repair. J Vasc Surg 2007;45:90-95. 17. Criado F. A percutaneous technique for preservation of arch branch patency during thoracic endovascular aortic repair (TEVAR): retrograde catheterization and stenting. J Encovasc Ther 2007;14:54-58. 18. Epstein D, Debord J. Abnormalities associated with aberrant right subclavian arteries-a case report. Vasc Endovascular Surg 2002;36:297-303. 19. Weinberger G, Randall A, Parker B, Kiefer A. Involvement of an aberrant right subclavian artery in dissection of the thoracic aorta: diagnostic and therapeutic implication. Am J Roentgenol 1977;129:653-655. 20. Mosquera V, Marini M, Rodriguez F, Cao I, Juffe A. Complicated acute type B aortic dissection with involvement of an aberrant right subclavian artery and rupture of a thoracoabdominal aortic aneurysm, Crawford type I: successful emergency endovascular treatment. J Thorac Cardiovasc Surg 2007;134:1055-1057. 21. Baccin C, Montegegro M, Mour~ao G. Thoracic aorta dissection associated with aberrant right subclavian artery: treatment with endovascular stent-graft placement. Yale J Biol Med 2004;77:59-62. 22. Syme J. Aortic dissection involving an aberrant right subclavian artery studied by aortography. Aust Radiol 1973;17:174-179. 23. Alcocer J, Spier L, Dyke C, Griffith B, Gammie J. Traumatic rupture of an aberrant right subclavian artery. Ann Thorac Surg 2000;69:621-623. 24. Bednarkiewicz M, Robert J, Khatchatourian G, Genin G, Irmay F, Faidutti B. Traumatic rupture of the aortic isthmus in a patient with an aberrant right subclavian artery: therapeutic implications. J Thorac Cardiovasc Surg 1999;118:1112-1113.