From the Society for Clinical Vascular Surgery
Left subclavian artery coverage during thoracic endovascular aortic repair: A single-center experience Edward Y. Woo, MD,a Jeffrey P. Carpenter, MD,a Benjamin M. Jackson, MD,a Alberto Pochettino, MD,b Joseph E. Bavaria, MD,b Wilson Y. Szeto, MD,b and Ronald M. Fairman, MD,a Philadelphia, Pa Objective: This study was conducted to determine the results of left subclavian artery (LSA) coverage during thoracic endovascular aortic repair (TEVAR). Methods: We retrospectively reviewed the results of 308 patients who underwent TEVAR from 1999 to 2007. The LSA was completely covered in 70 patients (53 men, 13 women), with a mean age of 67 years (range 41-89). Elective revascularization of the LSA was performed in 42 cases, consisting of transposition (n ⴝ 5), bypass and ligation (n ⴝ 3), or bypass and coil embolization (n ⴝ 34). Mean follow-up was 11 months (range, 1-48 months). The 2 test was used for statistical analysis. Results: Indications for treatment included aneurysm in 47, dissection in 16, transection in 4, pseudoaneurysm in 2, and right subclavian aneurysm in 1, with 47 elective and 23 emergency operations. Aortic coverage extended from the left common carotid artery (LCCA) to the distal arch (n ⴝ 29), middle thoracic aorta (n ⴝ 9), or celiac artery (n ⴝ 32). Operative success was 99%. The 30-day mortality was 4% (intraoperative myocardial infarction, 1; traumatic injuries, 1; visceral infarction, 1). No paraplegia developed. The stroke rate was 8.6%; no strokes were related to LSA coverage because there were no posterior strokes. Stroke rates between the revascularization (7%) and non-revascularization (11%) groups were not significantly different (P ⴝ .6). All but one patient fully recovered by 6 months. No left arm symptoms developed in patients with LSA revascularization. All bypasses remained patent throughout follow-up. One complication (2%) resulted in an asymptomatic persistently elevated left hemidiaphragm, likely related to phrenic nerve traction. Left upper extremity symptoms developed in five (18%) patients without LSA revascularization. Two required LSA revascularization, one of which was for acute limb-threatening ischemia. No permanent left upper extremity dysfunction or ischemia developed in any patient. Conclusion: Zone 2 TEVAR with LSA coverage can be accomplished safely in both elective and emergency settings and with and without revascularization (with the exception of a patent LIMA-LAD bypass). Nevertheless, overall stroke rates are higher compared with all-zone TEVAR. Staged LSA revascularization and even urgent revascularization may be necessary but can be performed without long-term detriment to the left arm. ( J Vasc Surg 2008;48:555-60.)
Thoracic endovascular aortic repair (TEVAR) has emerged as a promising alternative to open thoracic aortic repair. Thus far, early results have been excellent, with low morbidity and mortality rates.1-5 Although clinical trials have centered on treatment of atherosclerotic aneurysms, indications have expanded to include other aortic pathologies. There has been increasing interest in treating traumatic aortic injuries and aortic dissections.6-11 Traumatic injuries and dissections, especially, necessitate proximal extension of the graft to achieve an adequate landing zone. In these situations and with proximal aneurysms, coverage of the left subclavian artery (LSA) becomes necessary. Concerns for coverage in this area include posterior circulation From the Division of Vascular Surgery and Endovascular Therapya and Divsion of Cardiac Surgery,b Department of Surgery, University of Pennsylvania Health System. Competition of interest: none. Presented at the Annual Meeting of the Society for Clinical Vascular Surgery, Orlando, Fla, Mar 21-24, 2007. Reprint requests: Edward Y. Woo, Department of Surgery, 4 Silverstein, Hospital of the University of Pennsylvania, 3400 Spruce St, Philadelphia, PA 19104 (e-mail: [email protected]
). 0741-5214/$34.00 Copyright © 2008 by The Society for Vascular Surgery. doi:10.1016/j.jvs.2008.03.060
stroke, paraplegia, and arm ischemia.12-14 We describe our experience with zone 2 TEVAR. PATIENTS AND METHODS We retrospectively reviewed the records of 308 patients who underwent TEVAR from 1999 to 2007. Of those, 70 patients required coverage of the LSA. Patients were either treated as part of a clinical trial or with the use of a United States Food and Drug Administration–approved device. Grafts included the TAG (W. L. Gore & Associates, Flagstaff, Ariz) in 55 patients, the Talent (Medtronic, Minneapolis, Minn) in 14, and the TX2 (Cook, Bloomington, IN) in one. Choice of device was left to the discretion of the surgeon. Patient demographics are summarized in Table I. Thoracic stent delivery was approached through the common femoral artery in 58 patients or the common iliac artery in 12. No conduits were used for delivery. If iliac access was used, direct puncture of the vessel was performed. Briefly, two pursestring sutures were placed in the common iliac artery. Access was obtained at the center of the pursestring sutures. Upon completion of the TEVAR and sheath removal, the pursestrings were secured. This circumvented any conduit placement and any vessel occlusion. 555
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Table I. Patient demographics Variable Age Male Female Coronary artery disease Atrial fibrillation Congestive heart failure Hypertension Diabetes mellitus Hypercholesterolemia COPD Chronic renal insufficiency Patent LIMA
No. or Mean
% or SD
67 53 17 44 11 6 54 13 26 17 15 5
12 76 24 63 16 9 77 19 37 24 21 7
COPD, Chronic obstructive pulmonary disease; LIMA, left internal mammary artery.
All procedures were performed in the operating suite with either a mobile OEC9800 (GE, Milwaukee, Wisc) or fixed Siemens Axiom Artis FA (Siemens, Malvern, Pa). The decision for revascularization of the LSA was made by the operating surgeon. Preoperative LSA revascularization was performed in 42 patients, and five had a patent left internal mammary artery (LIMA) to left anterior descending artery (LAD) bypass. All revascularization procedures were performed through a left supraclavicular incision exposing both the left common carotid artery (LCCA) and LSA. Five cases were done by LSA to LCCA transposition. Three cases were performed by LCCA to LSA bypass with an 8-mm Dacron graft and concomitant ligation of the proximal LSA. The remaining 34 patients underwent LCCA to LSA bypass with an 8-mm Dacron graft and staged coil embolization of the proximal LSA during the TEVAR procedure. Briefly, the bypass was performed with arterial control distal to the left vertebral artery (LVA) and the LIMA, thereby preventing any ischemia to these vessels, with the bypass graft distal to these vessels as well. Access to the left brachial artery was obtained during the TEVAR procedure. After endograft deployment, coils were placed in the proximal LSA to prevent retrograde flow and a potential type II endoleak, allowing continued perfusion of the LVA and LIMA (Fig 1, A and B). Patient follow-up included history, physical examination, and computed tomography angiography (CTA). Patients were typically seen at 1, 6, and 12 months, and annually thereafter. During follow-up, patients were specifically assessed for neurologic changes and evidence of arm ischemia. CTA was used to assess for durability of the stent graft repair. Statistical analyses were performed with the 2 test using StatView 5.0.1 software (SAS Institute, Cary, NC). Survival was analyzed with the Kaplan-Meier method using SPSS Base 12.0 software (SPSS Inc, Chicago, Ill). RESULTS Indications for treatment included a variety of pathologies under elective and emergency circumstances (Table
II). All patients required zone 2 coverage. The distal landing zone involved the proximal thoracic aorta in 29, middle thoracic aorta in nine, or celiac artery in 32. Operative success rate, defined as treatment of aortic pathology without evidence of endoleak, was 99%. One patient had a persistent type I endoleak at the distal seal zone despite graft extension to the celiac artery. At the 12-month follow-up, the endoleak had sealed and the aneurysm sac was shrinking. Study group patients received an average of 2.4 pieces. The 30-day mortality rate was 4%. One patient had an acute thoracic aortic rupture 24 hours after the elective carotid-subclavian bypass. Despite successful emergency thoracic endografting, the patient died intraoperatively from a myocardial infarction (MI). A second patient had an emergency TEVAR procedure for an acute traumatic aortic transection. The TEVAR was successful, but the patient ultimately died of the traumatic injuries about 1 month later. Finally, one patient who had full coverage died of severe visceral ischemia/infarction after elective endograft repair for a 7-cm aneurysm despite a patent celiac and superior mesenteric artery. Major neurologic complications in this series were limited to strokes. No transient or permanent paraplegia developed. Transient paraparesis that developed in one patient with full thoracic aortic coverage resolved with augmentation of mean arterial pressures and drainage of cerebrospinal fluid. The stroke rate was 8.6%, comprising four perioperative events and two that occurred ⬎30 days (Table III). One of four patients with perioperative events had persistent right-sided hemiparesis through follow-up. Of the two patients who had postoperative events, one presented with left-sided paresthesias limited to 3 months and the other had transient aphasia. Although the stroke rates were slightly higher in the group without revascularization (11% vs 7%), this did not reach statistical significance (P ⫽ .6). Furthermore, no strokes occurred in the posterior circulation. The technical success rate for LSA revascularization was a 100%, and all bypasses remained patent throughout follow-up. One patient (2%) who had LSA transposition presented with an asymptomatic persistently elevated left hemidiaphragm, likely resulting from phrenic nerve traction. Bypasses were performed electively at a median of 10 days before TEVAR. Symptoms developed in five (18%) of the patients without LSA revascularization (Table IV). No patients sustained any permanent ischemic or neurologic dysfunction, although one patient did experience acute ischemia requiring urgent bypass. The overall perioperative complication rate associated with TEVAR was 28% (Table V). Mean follow-up was 11 months (range, 1-48 months). Mean survival was 39 months, with a 2-year survival rate of 81% (Fig 2). In the patients treated for aneurysms, the mean sac size decreased from 6.2 cm to 4.2 cm. The rate of endoleaks during the follow-up period was 16%. Two type I leaks (both at 12 months) and two type III leaks (3 and 6 months) were
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Fig 1. A, Retrograde flow is seen in the proximal left subclavian artery (arrow) after endograft placement. B, Coils placed in the proximal left subclavian artery inhibit retrograde flow to the endograft. The left internal mammary artery and the left vertebral artery remain patent (arrows).
Table II. Indications for treatment Indication
Table IV. Patients with symptomatic left upper extremity
42 1 2 ... 1
5 15 2 1 ...
Aneurysm Dissection Transection Pseudoaneurysm Right subclavian aneurysm
Table III. Distribution of neurologic events Patient
1 2 3 4 5 6
2 1 1 1 30 90
RMCA RMCA LMCA LMCA LMCA RMCA
LUE weakness/numbness LUE weakness Right hemiparesis Aphasia Aphasia Left paresthesias
LMCA, Left middle cerebral artery; LUE, left upper extremity; POD, postoperative day; RMCA, right middle cerebral artery.
detected and were resolved with a secondary endovascular procedure. Six type II leaks were found and required no intervention. No patients required open conversion. Two patients presented with a retrograde type A dissection at 3 and 12 months after TEVAR, and both underwent open operation. One patient survived and continues to do well, but the other died of the dissection. The original aortic pathology of these patients was dissection and aneurysm. Only one of these patients had a device with bare metal. DISCUSSION Results of TEVAR have demonstrated excellent periprocedural results, with good short- and midterm du-
1 2 3 4 5
6 5 360 90 2
Acute ischemia Cellulitis Finger discoloration Severe claudication Hand discoloration
Yes No No Yes No
POD, Postoperative day.
Table V. Perioperative complications Complication Groin wound Seroma Hematoma Access injury Iliac stent Iliac bypass Neurologic Stroke Paraparesis Atrial fibrillation
No. 4 3 1 8 4 4 5 4 1 3
rability.1-5 Proximal graft deployment, however, may be associated with increased morbidity.5,13 Coverage in zones 0 and 1 certainly carries increased risk given the need for hybrid procedures.15 Management of the LSA can be variable, however, depending on the patient and situation. Because LSA flow may be important for perfusion to the arm, posterior brain, and spinal cord, endograft deployment in this region may have various ramifications. Thus, we examined our experience at a single institution with zone 2 TEVAR.
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Fig 2. Kaplan-Meier survival curve for patient population. The patients (N) at risk at monthly time intervals were 0 (n ⫽ 66), 10 (n ⫽ 31), 20 (n ⫽ 10), 30 (n ⫽ 3), and 40 (n ⫽ 1) months.
The technical success rate was excellent. Although one patient had a residual distal type I endoleak, this resolved in follow-up. Interestingly, no patients had a proximal type I endoleak at the time of endograft placement; thus, LSA coverage allowed enough proximal extension to establish a seal. This endoleak rate was no worse than that found in other TEVAR series that did not focus on zone 2.16,17 Perioperative mortality was also no worse than other series.2,3 Two of the perioperative deaths were aneurysmrelated. One patient sustained a fatal MI despite endovascular exclusion of the aortic rupture. The period of hypotension associated with the rupture likely induced the coronary event, which was unrecoverable. The other patient sustained a severe visceral infarction. The celiac and superior mesenteric artery remained patent. Although initially stable, the patient decompensated. At an exploratory laparotomy on postoperative day 2, almost the entire small and large intestine were found to be infarcted, and the family withdrew care. Given that the visceral vessels were patent, the patient likely had an embolic event from manipulation in the visceral aorta. In general, intestinal ischemia is not common after TEVAR for aneurysmal disease; however, it can be seen in patients with malperfusion secondary to aortic dissection. Eight of the 16 patients in our series who were treated for dissection presented with malperfusion, but no intestinal infarction developed. No paraplegia developed in the 70 patients undergoing zone 2 TEVAR. One patient in the non-revascularized LSA group presented with transient unilateral lower extremity weakness that completely resolved with augmentation of mean arterial pressures and cerebrospinal fluid drainage. This had required full coverage of the thoracic aorta for an acute dissection. Certainly, the extent of coverage increases the risk of spinal cord ischemia.17 In addition, LSA coverage may also increase the risk of spinal cord ischemia.18 As expected, the stroke rate was higher given the more proximal extent of deployment.5,12 This is likely due to increased
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atheroma and arch manipulation.19-21 Manipulation of wires and catheters often engage the atheroemboli (Fig 3, A and B). The wires, catheters, and devices can subsequently dislodge embolic material right at the orifices of the great vessels. Interestingly, no events occurred in the posterior circulation, suggesting that coverage of the LSA without revascularization may not pose as much of a risk as arch manipulation itself. Of all the TEVAR patients we reviewed, 23% required coverage of the LSA, of which 60% had elective LSA revascularization. Indications for revascularization have included a dominant LVA; a stenotic, atretic, hypoplastic, absent right vertebral artery; an incomplete vertebrobasilar system, minimizing spinal cord ischemia, a history of arm ischemia, and a patent LIMA-LAD bypass. Other groups have certainly proceeded with coverage without revascularization of the LSA.14,22,23 Although our group initially evaluated patients for revascularization, we now perform carotid-subclavian bypasses on all elective zone 2 TEVAR cases. Given that the anterior spinal artery is partly formed from branches of the thyrocervical trunk, revascularization may be important for spinal cord perfusion.24 In addition, LSA revascularization has been shown to have some correlation in preventing spinal cord ischemia.18 Moreover, although acute upper extremity ischemia is rare, severe ischemia can occur.13,14,22 As a result, we prefer to proceed with LSA revascularization in all elective cases for spinal cord, upper extremity, and cerebrovascular protection. In emergency settings, however, it is not unreasonable to proceed with coverage without revascularization. Acute left upper extremity ischemia is rare, although one patient did present with this on postoperative day 6. An interesting find was that he did not have an aberrant LVA off the aortic arch as might be expected. Four other patients had left arm symptoms, of which only one required bypass. Thus in terms of the left upper extremity, coverage of the LSA orifice can likely be performed without long-term or permanent detriment. To achieve this, we developed the technique of bypass, followed by staged proximal LSA coil embolization at the time of endograft deployment.25 The benefit of this technique is that the LSA proximal to the LIMA and LVA never needs to be clamped or dissected. This is especially useful in patients with patent LIMA-LAD bypasses. It also avoids potentially hazardous mediastinal dissection from a supraclavicular approach in patients with large arch aneurysms that often deform the normal anatomy; in fact, sometimes the aneurysm can encroach upon the supraclavicular space and displace the LSA. Without the need for transposition or proximal ligation, dissection is minimized, thus preventing potential complications that can be seen with more extensive dissection.26 We generally prefer to wait several days after the bypass before initiating TEVAR. Concomitant procedures can lead to bleeding within the supraclavicular fossa. Regardless of the technique, revascularization can be done with minimal morbidity and excellent results.
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Fig 3. A, Axial transesophageal echocardiogram (TEE) image of the aortic arch shows the wire (arrow) traversing an atheromatous plaque. B, Sagittal TEE image of the aortic arch shows the wire (arrow) abutting an atheromatous plaque.
We observed a perioperative complication rate of 28%. Access-related injuries comprised almost 50%, and groin wound issues comprised another 25%. Our access-related issues were mostly early in our experience when we preferentially accessed the common femoral artery. We now routinely expose the common iliac artery if there is any question of caliber. We typically perform a direct puncture of the common iliac artery through preplaced pursestring sutures. As a result, we avoid using conduits altogether. During the follow-up period, mean aneurysm sac size decreased. Furthermore, the group demonstrated an acceptable rate of endoleaks. Four patients required secondary procedures to treat type I and type III endoleaks. Retrograde type A dissections occurred in two patients (3%), with 50% mortality. These lesions have been described after TEVAR and are very ominous, with significant associated morbidity and death.27,28 Although follow-up was limited to a mean of 11 months, overall mean survival was excellent and comparable with other studies.1,3 CONCLUSIONS Although this study is only a retrospective analysis representative of one institution, it does comprise a significant number of patients requiring zone 2 TEVAR. We show that TEVAR can be accomplished with minimal morbidity and mortality in this patient population. LSA revascularization, although ideal, is not mandatory before endograft deployment, especially in emergency settings. Patients with a patent LIMA-LAD bypass would serve as an exception. Finally, caution applies while manipulating the aortic arch, because stroke rates are clearly higher when patients undergo TEVAR in zone 2. AUTHOR CONTRIBUTIONS Conceptions and design: EW, AP, JB, SZ, RF, BJ Analysis and interpretation: EW, JC, AP, JB, WS, RF, BJ Data collection: EW
Writing the article: EW, BJ Critical revision of the article: EW, JC, AP, JB, WS, RF, BJ Final approval of the article: EW, JC, AP, JB, WS, RF, BJ Statistical analysis: EW, JC, BJ Obtained funding: EW, RF Overall responsibility: EW REFERENCES 1. Wheatley GH 3rd, Gurbuz AT, Rodriguez-Lopez JA, Ramaiah VG, Olsen D, Williams J, et al. Midterm outcome in 158 consecutive Gore TAG thoracic endoprostheses: single center experience. Ann Thorac Surg 2006;81:1570-7; discussion 1577. 2. Stone DH, Brewster DC, Kwolek CJ, Lamuraglia GM, Conrad MF, Chung TK, et al. Stent-graft versus open-surgical repair of the thoracic aorta: mid-term results. J Vasc Surg 2006;44:1188-97. 3. Fattori R, Nienaber CA, Rousseau H, Beregi JP, Heijmen R, Grabenwoger M, et al. Results of endovascular repair of the thoracic aorta with the Talent Thoracic stent graft: the Talent Thoracic Retrospective Registry. J Thorac Cardiovasc Surg 2006;132:332-9. 4. Bavaria JE, Appoo JJ, Makaroun MS, Verter J, Yu ZF, Mitchell RS. Endovascular stent grafting versus open surgical repair of descending thoracic aortic aneurysms in low-risk patients: a multicenter comparative trial. J Thorac Cardiovasc Surg 2007;133:369-77. 5. Go MR, Cho JS, Makaroun MS. Mid-term results of a multicenter study of thoracic endovascular aneurysm repair versus open repair. Perspect Vasc Surg Endovasc Ther 2007;19:124-30. 6. Neschis DG, Moaine S, Gutta R, Charles K, Scalea TM, Flinn WR, et al. Twenty consecutive cases of endograft repair of traumatic aortic disruption: lessons learned. J Vasc Surg 2007;45:487-92. 7. Midgley PI, Mackenzie KS, Corriveau MM, Obrand DI, Abraham CZ, Fata P, et al. Blunt thoracic aortic injury: A single institution comparison of open and endovascular management. J Vasc Surg 2007;46:662-8. 8. Saratzis NA, Saratzis AN, Melas N, Ginis G, Lioupis A, Lykopoulos D, et al. Endovascular repair of traumatic rupture of the thoracic aorta: single-center experience. Cardiovasc Intervent Radiol 2007;30:370-5. 9. Czerny M, Zimpfer D, Rodler S, Funovics M, Dorfmeister M, Schoder M, et al. Endovascular stent-graft placement of aneurysms involving the descending aorta originating from chronic type B dissections. Ann Thorac Surg 2007;83:1635-9. 10. Schoder M, Czerny M, Cejna M, Rand T, Stadler A, Sodeck GH, et al. Endovascular repair of acute type B aortic dissection: long-term follow-up of true and false lumen diameter changes. Ann Thorac Surg 2007;83:1059-66.
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