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Distal Aortic Arch Replacement for Aneurysmal Disease: The Value of Preparatory Carotid Subclavian Reconstruction
Distal Aortic Arch Replacement for Aneurysmal Disease: The Value of Preparatory Carotid Subclavian Reconstruction William J. Quin˜ones-Baldrich, MD,1 Daniel Marelli, MD,2 and Fardad Esmailian, MD,2 Los Angeles, California
Between November 2000 and January 2002, two patients with aneurysms that involved the distal part of the aortic arch including the left subclavian artery were treated at our institution. Patient 1 had an aneurysm of 5.8 cm extending to the proximal descending aorta. Patient 2 had a 6.8 cm type II thoracoabdominal aneurysm extending proximal to the aortic bifurcation. Both patients had left subclavian-to-carotid transposition in preparation for distal aortic arch replacement. Complete replacement of the descending thoracic and abdominal aorta was carried out in patient 2. Both cases were done with distal aortic perfusion, spinal catheter drainage, and dual lumen endotracheal anesthesia. There was no mortality. There were no cerebrovascular complications in spite of the fact that patient 1 required aortic cross-clamping between the innominate and left carotid artery. There was no paraplegia, renal failure, or mesenteric or lower extremity complications. Patient 1 had postoperative vocal cord palsy, eventually requiring medialization procedure. He recovered normal voice. Both patients remain alive and well at the time of last follow-up (7 to 20 months). Carotid subclavian reconstruction in preparation for distal aortic arch replacement facilitates the performance of the proximal anastomosis and attempts to maintain flow through the left vertebral system during aortic cross-clamping. This may reduce the risk of stroke during distal aortic arch replacement.
INTRODUCTION
1 Division of Vascular Surgery, University of California Los Angeles, Los Angeles, CA. 2 Division of Cardiothoracic Surgery, University of California Los Angeles, Los Angeles, CA.
Presented at the Twentieth Annual Meeting of the Southern California Vascular Surgical Society, Rancho Bernardo, CA, April 19-21, 2002. Correspondence to: W.J. Quin˜ones-Baldrich, MD, Division of Vascular Surgery, UCLA Center of the Health Sciences, 10833 Le Conte Avenue, Los Angeles, CA 90095, USA, E-mail: [email protected]. Ann Vasc Surg 2003; 17: 148-151 DOI: 10.1007/s10016-001-0399-7 Annals of Vascular Surgery Inc. Published online: 6 March 2003 148
Thoracic aortic aneurysms usually occur distal to the origin of the left subclavian artery. On occasion, however, proximal involvement includes the origin of the left subclavian artery, requiring replacement of the distal aortic arch for appropriate repair. Revascularization of the subclavian artery during repair of these aneurysms has traditionally been accomplished by inclusion of the origin of the subclavian artery in the proximal anastomosis. Alternatively, involvement the left subclavian artery may be managed by ligation, or using bypass with a separate graft. We report two cases of thoracic and thoracoabdominal aneurysms with involvement of the left subclavian artery. In both cases, the pa-
Vol. 17, No. 2, 2003
Preparatory carotid subclavian reconstruction 149
cigarettes but had no history of diabetes mellitus. On physical examination his blood pressure was equal in both upper extremities at 110/80 and there were no carotid bruits. Magnetic resonance angiography (MRA) confirmed involvement of the origin of the left subclavian artery (Fig. 1). The patient was admitted for elective repair in November of 2000. At that time he underwent a left subclavian–to–carotid artery transposition and under the same anesthetic underwent repair of the proximal aortic aneurysm through distal arch replacement with a 24-mm Dacron graft. Distal aortic perfusion was accomplished with an extracorporeal centrifugal pump from the left atrium to left femoral artery. The aneurysm was heavily calcified and an inflammatory process prevented clamping between the left carotid and the left subclavian artery, thus the clamp was placed proximal to the left carotid artery. Patient 2
Fig. 1. MRA in patient 1 showing aneurysmal process proximal to left subclavian artery. The patient underwent preparatory carotid subclavian transposition.
tients underwent preparatory carotid subclavian bypass prior to distal aortic arch replacement.
PATIENTS AND METHODS Between November 2000 and January of 2002, two patients with aneurysms that involved the distal part of the aortic arch including the left subclavian artery were treated at our institution. The following is a clinical summary of the patients. Patient 1 This is a 63-year-old white male who on routine chest X-ray was found to have a widened mediastinum. A CT scan revealed a proximal descending aortic aneurysm measuring 3.8 · 5.8 cm. He was asymptomatic. The patient had history of a motor vehicle accident in 1958, at which time he required a craniotomy. The patient also had history of atrial fibrillation since age 40 and of hypertension and hypercholesterolemia. He was an ex-smoker of
This is a 44-year-old female with history of an ascending aortic aneurysm repaired with a Bentall procedure in 1991. A tissue valve for aortic valve replacement was utilized. The patient did well until approximately October of 2001, when she had increasing dyspnea and chest pain. A CT scan at that time revealed a 6.8-cm type II thoracoabdominal aneurysm starting just proximal to the left subclavian artery and extending to the infrarenal aorta proximal to the inferior mesenteric artery. Arch angiography with oblique views confirmed involvement of the left subclavian artery (Fig. 2). The patient had no history of hypertension, diabetes mellitus, myocardial infraction, or stroke. On physical examination she had some features suggestive of Marfan’s syndrome, having undergone cataract surgery in the past. This diagnosis could not be confirmed, however. She had a grade III aortic systolic murmur and a palpable 3-cm abdominal aortic aneurysm. She had full pulses in all extremities. The patient was admitted in December of 2001 for elective repair of her thoracoabdominal aneurysm. She underwent a left subclavian-to-carotid transposition and under the same anesthetic underwent replacement of the distal aortic arch and repair of a type II thoracoabdominal aneurysm with a 28-mm Dacron graft. The distal repair included reimplantation of intercostals at the T10, celiac, superior mesenteric, and right renal arteries in a single patch, left renal artery reimplantation on a separate patch, and aortoaortic anastomosis proximal to the inferior mesenteric artery. Distal aortic
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neurologic deficits. The patient was discharged home 10 days after surgery and remains well as of last follow-up (7 months).
DISCUSSION
Fig. 2. Arch aortogram in patient 2. Top and bottom: oblique views show involvement of the left subclavian artery in the proximal portion of a 6.8-cm type II thoracoabdominal aneurysm. Note tortuosity of left subclavian artery (bottom).
perfusion was accomplished between the left inferior pulmonary vein and left external iliac artery.
RESULTS There was no mortality. There was no paraplegia, renal failure, or mesenteric or lower extremity complications. Both patients had palpable left radial pulse with equal upper extremity blood pressure. Patient 1 had an uneventful recovery. His preoperative creatinine was 1.2. His creatinine was 1.0 immediately following surgery and 3 weeks later it was 0.8. He was discharged 8 days after surgery with his only complaint being a breathy voice. In May 2001, the patient underwent a medial vocalization procedure with recovery of his normal voice. He has remained well as of last follow-up (20 months). Patient 2 had an uneventful recovery. Her preoperative creatinine was 0.5 and her postoperative creatinine ranged from 0.8 to 0.5. She had no
Involvement of the left subclavian artery origin in the presence of a proximal thoracic aneurysm increases the complexity of the repair. Alternatives for management of the left subclavian artery include ligation, reimplantation, incorporation in the proximal anastomosis, or bypass graft with a separate graft limb. We report two cases in which the left subclavian process was managed with a preparatory carotid subclavian reconstruction. Review of the literature failed to reveal any individual report of preparatory carotid subclavian reconstruction prior to surgical repair of a descending aortic aneurysm. Several reports on preparatory carotid subclavian bypasses have been published in preparation for endovascular repair of descending thoracic aneurysms.1,2 In those cases, the aneurysmal process starts distal to the origin of the left subclavian artery and the preparatory carotid subclavian reconstruction is done to lengthen the potential neck for implantation of the endovascular graft. It is likely that in the reported experience with thoracic and thoracoabdominal aneurysm repair, several patients with involvement of the left subclavian artery have been included.3-8 However, no mention is made as to the specific management of this particular problem. Others have reported use of hypothermic arrest for distal arch replacement.9 However, high mortality (26%) would argue for a simpler approach. In the very limited experience reported here, preparatory carotid subclavian reconstruction simplified the operative management, particularly when significant inflammatory process prevented encircling the distal aortic arch just proximal to the aneurysmal process. Thus this procedure facilitated performance of the proximal anastomoses where utilization of the aortic tissue around the subclavian artery could be incorporated for a more sound proximal anastomosis. This also reduces the amount of manipulation around the aortic arch, which may reduce the risk of perioperative cerebrovascular complications. Subclavian artery ligation is an alternative in the management of these lesions. On the basis of reports of traumatic injuries to the subclavian artery, it is difficult to anticipate the clinical consequences of ligation as patients with trauma have complicating factors, particularly neurologic injury to the
Vol. 17, No. 2, 2003
brachial plexus.10 However, one could anticipate that at least 20% of these patients will have significant ischemia of the extremity, and are at risk of posterior circulation stroke from acute ligation of that system.11 It is preferable to maintain normal perfusion if possible. In terms of preparatory carotid subclavian reconstruction, a bypass with synthetic graft or transposition is best, as demonstrated by our group12 and others.13,14 Both of our cases were done with distal aortic perfusion, spinal catheter drainage, and single lung endotracheal anesthesia. Although distal aortic perfusion has been shown to decrease the risk of paraplegia in type II and III thoracoabdominal aneurysm replacement, a definite reduction has not been demonstrated for type I thoracic aneurysms (patient 1).3 Nevertheless, in the presence of involvement of the subclavian artery, where the proximal anastomosis is more challenging, distal aortic perfusion allows for appropriate control of the hemodynamics and maintenance of flow to the abdominal viscera and lower extremities. This is supported by the absence of organ dysfunction in these cases. We conclude that preparatory carotid subclavian reconstruction prior to distal aortic arch replacement facilitates performance of the proximal anastomosis and attempts to maintain flow through the vertebral system on the left side during aortic cross-clamping. This may reduce the risk of stroke during distal aortic arch replacement. REFERENCES 1. Yano OJ, Faries PL, Morrissey N, et al. Ancillary techniques to facilitate endovascular repair of aortic aneurysms. J Vasc 2001;34:69-75.
Preparatory carotid subclavian reconstruction 151
2. Kato M, Kaneko M, Kuratani T, et al. New operative method for distal aortic arch aneurysm: combined cervical branch bypass and endovascular stent-graft implantation. J Thorac Cardiovasc Surg 1999;117:832-834. 3. Safi HJ, Hess KR, Randel M, et al. Cerebrospinal fluid drainage and distal aortic perfusion: reducing neurologic complications in repair of thoracoabdominal aortic aneurysm types I and II. J Vasc Surg 1996;23:223-229. 4. Svensson LG, Crawford ES, Hess KR, et al. Experience with 1509 patients undergoing thoracoabdominal aortic operations. J Vasc Surg 1993;17:357-370. 5. Svensson LG, Coselli JS, Safi HJ, et al. Appraisal of adjuncts to prevent acute renal failure after surgery on the thoracic or thoracoabdominal aorta. J Vasc Surg 1989;10:230-239. 6. Fehrenbacher JW, McCready RA, Hormuth DA, et al. Onestage segmental resection of extensive thoracoabdominal aneurysms with left-sided heart bypass. J Vasc Surg 1993;18:366-371. 7. Hamerlijnch RP, Rutsaert RR, De Geest R, et al. Surgical correction of descending thoracic aortic aneurysms under simple aortic cross-clamping. J Vasc Surg 1989;9:568573. 8. Cambria RP, Davison JK, Carter C, et al. Epidural cooling for spinal cord protection during thoracoabdominal aneurysm repair: a five-year experience. J Vasc Surg 2000;31:10931102. 9. Kieffer E, Koskas F, Walden R, et al. Hypothermic circulatory arrest for thoracic aneurysmectomy through left-sided thoracotomy. J Vasc Surg 1994;19:457-464. 10. Guloglu R, Bilsel Y, Alis H, et al. Traumatic subclavian and axillary vessel injuries. Int J Angiogr 1999;8:105-108. 11. Grahm JM, Feliciano DV, Mattox KL, et al. Management of subclavian vascular injuries. J Trauma 1980;20:537554. 12. Ziomek S, Quin˜ ones-Baldrich WJ, Busuttil RW, et al. The superiority of synthetic arterial grafts over autologous veins in carotid-subclavian bypass. J Vasc Surg 1986;3:140145. 13. Vitti MJ, Thompson BW, Read RC, et al. Carotid-subclavian bypass: a twenty-two-year experience. J Vasc Surg 1994; 20:411-418. 14. Cina´ CS, Safar HA, Lagana´ A, et al. Subclavian carotid transposition and bypass grafting: consecutive cohort study and systemic review. J Vasc Surg 2002;35:422-429.
Between November 2000 and January 2002, two patients with aneurysms that involved the distal part of the aortic arch including the left subclavian artery were treated at our institution. Patient 1 had an aneurysm of 5.8 cm extending to the proximal descending aorta. Patient 2 had a 6.8 cm type II thoracoabdominal aneurysm extending proximal to the aortic bifurcation. Both patients had left subclavian-to-carotid transposition in preparation for distal aortic arch replacement. Complete replacement of the descending thoracic and abdominal aorta was carried out in patient 2. Both cases were done with distal aortic perfusion, spinal catheter drainage, and dual lumen endotracheal anesthesia. There was no mortality. There were no cerebrovascular complications in spite of the fact that patient 1 required aortic cross-clamping between the innominate and left carotid artery. There was no paraplegia, renal failure, or mesenteric or lower extremity complications. Patient 1 had postoperative vocal cord palsy, eventually requiring medialization procedure. He recovered normal voice. Both patients remain alive and well at the time of last follow-up (7 to 20 months). Carotid subclavian reconstruction in preparation for distal aortic arch replacement facilitates the performance of the proximal anastomosis and attempts to maintain flow through the left vertebral system during aortic cross-clamping. This may reduce the risk of stroke during distal aortic arch replacement.
INTRODUCTION
1 Division of Vascular Surgery, University of California Los Angeles, Los Angeles, CA. 2 Division of Cardiothoracic Surgery, University of California Los Angeles, Los Angeles, CA.
Presented at the Twentieth Annual Meeting of the Southern California Vascular Surgical Society, Rancho Bernardo, CA, April 19-21, 2002. Correspondence to: W.J. Quin˜ones-Baldrich, MD, Division of Vascular Surgery, UCLA Center of the Health Sciences, 10833 Le Conte Avenue, Los Angeles, CA 90095, USA, E-mail: [email protected]. Ann Vasc Surg 2003; 17: 148-151 DOI: 10.1007/s10016-001-0399-7 Annals of Vascular Surgery Inc. Published online: 6 March 2003 148
Thoracic aortic aneurysms usually occur distal to the origin of the left subclavian artery. On occasion, however, proximal involvement includes the origin of the left subclavian artery, requiring replacement of the distal aortic arch for appropriate repair. Revascularization of the subclavian artery during repair of these aneurysms has traditionally been accomplished by inclusion of the origin of the subclavian artery in the proximal anastomosis. Alternatively, involvement the left subclavian artery may be managed by ligation, or using bypass with a separate graft. We report two cases of thoracic and thoracoabdominal aneurysms with involvement of the left subclavian artery. In both cases, the pa-
Vol. 17, No. 2, 2003
Preparatory carotid subclavian reconstruction 149
cigarettes but had no history of diabetes mellitus. On physical examination his blood pressure was equal in both upper extremities at 110/80 and there were no carotid bruits. Magnetic resonance angiography (MRA) confirmed involvement of the origin of the left subclavian artery (Fig. 1). The patient was admitted for elective repair in November of 2000. At that time he underwent a left subclavian–to–carotid artery transposition and under the same anesthetic underwent repair of the proximal aortic aneurysm through distal arch replacement with a 24-mm Dacron graft. Distal aortic perfusion was accomplished with an extracorporeal centrifugal pump from the left atrium to left femoral artery. The aneurysm was heavily calcified and an inflammatory process prevented clamping between the left carotid and the left subclavian artery, thus the clamp was placed proximal to the left carotid artery. Patient 2
Fig. 1. MRA in patient 1 showing aneurysmal process proximal to left subclavian artery. The patient underwent preparatory carotid subclavian transposition.
tients underwent preparatory carotid subclavian bypass prior to distal aortic arch replacement.
PATIENTS AND METHODS Between November 2000 and January of 2002, two patients with aneurysms that involved the distal part of the aortic arch including the left subclavian artery were treated at our institution. The following is a clinical summary of the patients. Patient 1 This is a 63-year-old white male who on routine chest X-ray was found to have a widened mediastinum. A CT scan revealed a proximal descending aortic aneurysm measuring 3.8 · 5.8 cm. He was asymptomatic. The patient had history of a motor vehicle accident in 1958, at which time he required a craniotomy. The patient also had history of atrial fibrillation since age 40 and of hypertension and hypercholesterolemia. He was an ex-smoker of
This is a 44-year-old female with history of an ascending aortic aneurysm repaired with a Bentall procedure in 1991. A tissue valve for aortic valve replacement was utilized. The patient did well until approximately October of 2001, when she had increasing dyspnea and chest pain. A CT scan at that time revealed a 6.8-cm type II thoracoabdominal aneurysm starting just proximal to the left subclavian artery and extending to the infrarenal aorta proximal to the inferior mesenteric artery. Arch angiography with oblique views confirmed involvement of the left subclavian artery (Fig. 2). The patient had no history of hypertension, diabetes mellitus, myocardial infraction, or stroke. On physical examination she had some features suggestive of Marfan’s syndrome, having undergone cataract surgery in the past. This diagnosis could not be confirmed, however. She had a grade III aortic systolic murmur and a palpable 3-cm abdominal aortic aneurysm. She had full pulses in all extremities. The patient was admitted in December of 2001 for elective repair of her thoracoabdominal aneurysm. She underwent a left subclavian-to-carotid transposition and under the same anesthetic underwent replacement of the distal aortic arch and repair of a type II thoracoabdominal aneurysm with a 28-mm Dacron graft. The distal repair included reimplantation of intercostals at the T10, celiac, superior mesenteric, and right renal arteries in a single patch, left renal artery reimplantation on a separate patch, and aortoaortic anastomosis proximal to the inferior mesenteric artery. Distal aortic
150 Quin˜ones-Baldrich et al.
Annals of Vascular Surgery
neurologic deficits. The patient was discharged home 10 days after surgery and remains well as of last follow-up (7 months).
DISCUSSION
Fig. 2. Arch aortogram in patient 2. Top and bottom: oblique views show involvement of the left subclavian artery in the proximal portion of a 6.8-cm type II thoracoabdominal aneurysm. Note tortuosity of left subclavian artery (bottom).
perfusion was accomplished between the left inferior pulmonary vein and left external iliac artery.
RESULTS There was no mortality. There was no paraplegia, renal failure, or mesenteric or lower extremity complications. Both patients had palpable left radial pulse with equal upper extremity blood pressure. Patient 1 had an uneventful recovery. His preoperative creatinine was 1.2. His creatinine was 1.0 immediately following surgery and 3 weeks later it was 0.8. He was discharged 8 days after surgery with his only complaint being a breathy voice. In May 2001, the patient underwent a medial vocalization procedure with recovery of his normal voice. He has remained well as of last follow-up (20 months). Patient 2 had an uneventful recovery. Her preoperative creatinine was 0.5 and her postoperative creatinine ranged from 0.8 to 0.5. She had no
Involvement of the left subclavian artery origin in the presence of a proximal thoracic aneurysm increases the complexity of the repair. Alternatives for management of the left subclavian artery include ligation, reimplantation, incorporation in the proximal anastomosis, or bypass graft with a separate graft limb. We report two cases in which the left subclavian process was managed with a preparatory carotid subclavian reconstruction. Review of the literature failed to reveal any individual report of preparatory carotid subclavian reconstruction prior to surgical repair of a descending aortic aneurysm. Several reports on preparatory carotid subclavian bypasses have been published in preparation for endovascular repair of descending thoracic aneurysms.1,2 In those cases, the aneurysmal process starts distal to the origin of the left subclavian artery and the preparatory carotid subclavian reconstruction is done to lengthen the potential neck for implantation of the endovascular graft. It is likely that in the reported experience with thoracic and thoracoabdominal aneurysm repair, several patients with involvement of the left subclavian artery have been included.3-8 However, no mention is made as to the specific management of this particular problem. Others have reported use of hypothermic arrest for distal arch replacement.9 However, high mortality (26%) would argue for a simpler approach. In the very limited experience reported here, preparatory carotid subclavian reconstruction simplified the operative management, particularly when significant inflammatory process prevented encircling the distal aortic arch just proximal to the aneurysmal process. Thus this procedure facilitated performance of the proximal anastomoses where utilization of the aortic tissue around the subclavian artery could be incorporated for a more sound proximal anastomosis. This also reduces the amount of manipulation around the aortic arch, which may reduce the risk of perioperative cerebrovascular complications. Subclavian artery ligation is an alternative in the management of these lesions. On the basis of reports of traumatic injuries to the subclavian artery, it is difficult to anticipate the clinical consequences of ligation as patients with trauma have complicating factors, particularly neurologic injury to the
Vol. 17, No. 2, 2003
brachial plexus.10 However, one could anticipate that at least 20% of these patients will have significant ischemia of the extremity, and are at risk of posterior circulation stroke from acute ligation of that system.11 It is preferable to maintain normal perfusion if possible. In terms of preparatory carotid subclavian reconstruction, a bypass with synthetic graft or transposition is best, as demonstrated by our group12 and others.13,14 Both of our cases were done with distal aortic perfusion, spinal catheter drainage, and single lung endotracheal anesthesia. Although distal aortic perfusion has been shown to decrease the risk of paraplegia in type II and III thoracoabdominal aneurysm replacement, a definite reduction has not been demonstrated for type I thoracic aneurysms (patient 1).3 Nevertheless, in the presence of involvement of the subclavian artery, where the proximal anastomosis is more challenging, distal aortic perfusion allows for appropriate control of the hemodynamics and maintenance of flow to the abdominal viscera and lower extremities. This is supported by the absence of organ dysfunction in these cases. We conclude that preparatory carotid subclavian reconstruction prior to distal aortic arch replacement facilitates performance of the proximal anastomosis and attempts to maintain flow through the vertebral system on the left side during aortic cross-clamping. This may reduce the risk of stroke during distal aortic arch replacement. REFERENCES 1. Yano OJ, Faries PL, Morrissey N, et al. Ancillary techniques to facilitate endovascular repair of aortic aneurysms. J Vasc 2001;34:69-75.
Preparatory carotid subclavian reconstruction 151
2. Kato M, Kaneko M, Kuratani T, et al. New operative method for distal aortic arch aneurysm: combined cervical branch bypass and endovascular stent-graft implantation. J Thorac Cardiovasc Surg 1999;117:832-834. 3. Safi HJ, Hess KR, Randel M, et al. Cerebrospinal fluid drainage and distal aortic perfusion: reducing neurologic complications in repair of thoracoabdominal aortic aneurysm types I and II. J Vasc Surg 1996;23:223-229. 4. Svensson LG, Crawford ES, Hess KR, et al. Experience with 1509 patients undergoing thoracoabdominal aortic operations. J Vasc Surg 1993;17:357-370. 5. Svensson LG, Coselli JS, Safi HJ, et al. Appraisal of adjuncts to prevent acute renal failure after surgery on the thoracic or thoracoabdominal aorta. J Vasc Surg 1989;10:230-239. 6. Fehrenbacher JW, McCready RA, Hormuth DA, et al. Onestage segmental resection of extensive thoracoabdominal aneurysms with left-sided heart bypass. J Vasc Surg 1993;18:366-371. 7. Hamerlijnch RP, Rutsaert RR, De Geest R, et al. Surgical correction of descending thoracic aortic aneurysms under simple aortic cross-clamping. J Vasc Surg 1989;9:568573. 8. Cambria RP, Davison JK, Carter C, et al. Epidural cooling for spinal cord protection during thoracoabdominal aneurysm repair: a five-year experience. J Vasc Surg 2000;31:10931102. 9. Kieffer E, Koskas F, Walden R, et al. Hypothermic circulatory arrest for thoracic aneurysmectomy through left-sided thoracotomy. J Vasc Surg 1994;19:457-464. 10. Guloglu R, Bilsel Y, Alis H, et al. Traumatic subclavian and axillary vessel injuries. Int J Angiogr 1999;8:105-108. 11. Grahm JM, Feliciano DV, Mattox KL, et al. Management of subclavian vascular injuries. J Trauma 1980;20:537554. 12. Ziomek S, Quin˜ ones-Baldrich WJ, Busuttil RW, et al. The superiority of synthetic arterial grafts over autologous veins in carotid-subclavian bypass. J Vasc Surg 1986;3:140145. 13. Vitti MJ, Thompson BW, Read RC, et al. Carotid-subclavian bypass: a twenty-two-year experience. J Vasc Surg 1994; 20:411-418. 14. Cina´ CS, Safar HA, Lagana´ A, et al. Subclavian carotid transposition and bypass grafting: consecutive cohort study and systemic review. J Vasc Surg 2002;35:422-429.