- Email: [email protected]
Anatomic exclusion from endovascular repair of thoracic aortic aneurysm
From the Society for Clinical Vascular Surgery
Anatomic exclusion from endovascular repair of thoracic aortic aneurysm Benjamin M. Jackson, MD, Jeffrey P. Carpenter, MD, Ronald M. Fairman, MD, G. William Moser, MSN, RN, Alberto Pochettino, MD, Edward Y. Woo, MD, and Joseph E. Bavaria, MD, Philadelphia, Pa Objectives: We sought to define the current anatomic barriers to thoracic aortic aneurysm (TAA) stent grafting to guide future device development. Methods: All patients presenting with TAA requiring repair were evaluated for endovascular repair during a 4-year period (2000 to 2004). The TAAs evaluated were those beginning distal to the left common carotid artery (LCCA) and ending proximal to the celiac artery. All patients in whom endovascular repair was indicated underwent cross-sectional imaging by computed tomography angiography and three-dimensional modeling of their thoracic and abdominal arterial anatomy. Patients were evaluated for endovascular TAA repair in the context of the inclusion/exclusion criteria of pivotal United States Food and Drug Administration trials of the Gore TAG and Medtronic Talent devices. Anatomic requirements included >20 mm of suitable proximal and distal neck length, and proximal and distal neck diameters of 20 to 42 mm. These trials allowed the use of femoral or iliac access, including the use of conduits, and permitted stent graft coverage of the left subclavian artery (LSA) after preliminary carotid–subclavian bypass. Patients rejected for medical reasons or who died during evaluation were not included in the review. Results: A total of 126 patients (73 men, 53 women) with TAA located between the LCCA and celiac artery were screened for endovascular repair, and 33 (26%) were rejected for anatomic reasons. The remaining 93 patients underwent endografting (59 Talent, 34 TAG). Rejection was not significantly different by gender (16/73 men, 17/53 women, P ⴝ .22, NS). Most patients (28/33) were rejected for more than one criterion. Hostile proximal neck characteristics were the most prevalent reason for disqualification, despite the ability to cover the LSA to extend the proximal seal zone. Many of these patients (16/28) also had distal neck anatomy unsuitable for grafting. Overall, 19 patients had hostile distal necks. Difficulties with vascular access (diseased or tortuous iliac arteries, or a small caliber aorta) that could not be overcome even by use of conduits occurred in a significant fraction of patients (10/33). Conclusions: Most patients with a TAA located between the LCCA and the celiac artery can be treated by endovascular repair. Patients excluded from TAA stent graft protocols for anatomic reasons most commonly have hostile proximal neck features that preclude endovascular repair with currently available devices. Transposition of arch vessels to facilitate greater use of existing stent grafts or development of new stent graft designs are needed to expand the applicability of TAA endovascular repair. ( J Vasc Surg 2007;45:662-6.)
Thoracic aortic aneurysms (TAAs) are currently being treated, with much success, by using stent grafting1-3; however, not all patients with TAAs are eligible for these lessinvasive endovascular repairs. Proximal and distal fixation and involvement of aortic branches in aneurysmal segments have been identified as barriers to more widespread application of thoracic endovascular aneurysm repair (TEVAR).4 The analysis of anatomic features of aneurysms that make endovascular repair challenging or impossible will guide the development of the next generation of devices. Open repair of TAAs carries significant risks of morbidity and mortality, including pulmonary and cardiac complications, bleeding, wound problems, and neurovascular compromise. Although endografting does not eliminate all of these risks, it is associated with significantly smaller perioperative From the Hospital of the University of Pennsylvania. Competition of interest: none. Presented at the 2006 Annual Symposium of the Society for Clinical Vascular Surgery, Las Vegas, Nev, March 8-11, 2006. Correspondence: Dr Benjamin M. Jackson, 4 Maloney Building, Department of Surgery, Hospital of the University of Pennsylvania, 3400 Spruce St, Philadelphia, PA 19130 (e-mail: [email protected]). 0741-5214/$32.00 Copyright © 2007 by The Society for Vascular Surgery. doi:10.1016/j.jvs.2006.12.062
662
mortality and a shorter hospital stay.5 Contained ruptures of TAAs have likewise been successfully treated using TEVAR,6-8 expanding the applicability of the technique but further straining the existing approved devices. Many TAAs cannot be stented without coverage of branch vessels. Extra-anatomic bypass of visceral vessels, followed by TEVAR, has been required given the limitations of currently available stents.9-11 Arch vessel bypass has been widely used to treat aortic arch aneurysms using TEVAR.12,13 Treatment of thoracoabdominal and aortic arch aneurysms with fenestrated and branched endografts is being more widely accepted and applied.14-21 In an attempt to delineate the limitations of the current generation of endografts, better define the needed design elements in the next generation, and assess the proportion of patients with TAA who will not be treatable with current endografts, we examined isolated descending TAAs, identifying those patients who were excluded from clinical trials for widely used thoracic endografts because of hostile anatomic features. METHODS Study design. We identified all patients evaluated for endovascular repair of isolated TAA at the Hospital of the
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Table I. Exclusion criteria for sponsored, controlled clinical trials Gore TAG
Medtronic Talent
*Nonaneurysmal segment at either neck ⬍2 cm Diameter at either neck ⬍23 mm or ⬎37 mm Occluded LCCA or CA “Significant thrombus” at either neck Proximal neck angulated ⬍60° Taper at either neck ⬎ 4 mm
*Nonaneurysmal segment at either neck ⬍2 cm Diameter at either neck ⬍18 mm or ⬎42 mm Clearance at LCCA or CA ⬍20 mm “Significant mural thrombus” at either neck Access vessel “precludes safe insertion of delivery system
LCCA, Left common carotid artery; CA, celiac artery. *Including, where necessary, the segment involving the takeoff of the left subclavian artery.
Table II. Clinical outcomes of the 33 patients excluded from endovascular stent grafting
Table III. Rejection criteria for all 33 patients, in compendium
Outcome
n
Criteria
n
TEVAR after LCCA-LSCA bypass TEVAR with partial occlusion of CA Open repair with left atrial-femoral artery bypass Open repair with hypothermic circulatory arrest Not repaired at this institution
2 1 3 2 25
Short proximal neck
16 Proximal neck anatomy 10 6 2 9 2 7 Distal neck anatomy 5 1 13 9 Access anatomy 1 1
TEVAR, thoracic endovascular aneurysm repair; LCCA, left common carotid artery; LSCA, left subclavian artery; CA, celiac artery.
University of Pennsylvania between 2000 and 2004. Patients with aneurysmal segments proximal to the left common carotid artery (LCCA) or distal to the celiac axis were not included in this study. All patients in whom TEVAR was indicated underwent cross-sectional imaging by computed tomography angiogram and subsequent threedimensional modeling by Medical Metrix Solutions (MMS, West Lebanon, NH). All patients were evaluated for either the Gore TAG endoprosthesis (W. L. Gore & Associates, Flagstaff, Ariz) or the Medtronic Talent graft (Medtronic, Minneapolis, Minn), or both. Patients were excluded from TEVAR repair on the clinical judgment of the surgeons participating in the trials, who were familiar with the anatomic exclusion criteria defined by the controlled clinical trials sponsored for the two devices (Table I). After each patient’s anatomy was analyzed, the excluding features were grouped according to broad categories: hostile proximal neck, hostile distal neck, or inadequate access vessels. Outcomes and follow-up. All patients initially rejected for TEVAR repair of a TAA for anatomic reasons were followed up to assess clinical outcome and eventual open or endovascular repair. Statistical analysis. All statistical calculations were performed by using SPSS software (SPSS Inc, Chicago, Ill). The Fisher exact test with a two-tailed assumption was used to assess for gender-based differences in rejection for TEVAR and for gender-based differences in the anatomic features leading to exclusion. Data are presented as mean ⫾ standard deviation, unless otherwise indicated. KaplanMeier statistics were used to analyze survival of the untreated patients.
Wide proximal neck Excessive proximal taper Angulated proximal neck Proximal neck thrombus Proximal neck calcification Short distal neck Wide distal neck Excessive distal taper Distal neck thrombus Narrow or tortuous iliac arteries Iliac occlusive disease Narrow aorta
Category
n 28
19
10
RESULTS Between 2000 and 2004, 126 patients (73 men and 53 women) with isolated TAA were evaluated (P ⫽ .05), and 33 (26%; 16 men, 17 women, P ⫽ .22) were rejected for TEVAR on anatomic grounds. These patients were generally ⬎70 years old (25, 75%), their aneurysms were of significant size, 6.4 ⫾ 1.4 cm, and most (85%) were excluded for meeting more than one criterion (mean, 2.5 ⫾ 1.2 criteria). Clinical outcomes for those patients excluded from TEVAR are summarized in Table II. Of the 33 patients excluded, 25 did not undergo repair of their aneurysms at our institution owing to some combination of relatively small aneurysms, medical unsuitability for open operation, and patient unwillingness to undergo open repair. The exclusion criteria were grouped according to category: 28 patients had hostile proximal neck anatomy, 19 had hostile distal neck anatomy, and 10 had access anatomy making TEVAR difficult or impossible. Both the specific excluding anatomic features and their broad categorization are presented in Table III. There was no gender-based difference in proportion of aneurysms with hostile proximal necks (13 men and 15 women, P ⫽ .66), hostile distal necks (11 men and 8 women, P ⫽ .29), or both (9 men and 7 women, P ⫽ .49). Women had a tendency toward being more likely to have difficult access anatomy (3 men and 7 women, P ⫽ .25), but this difference did not reach statistical significance.
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Fig 1. A Venn diagram demonstrates the clustering of patients according to exclusion criteria category. Note that fully 28 of 33 patients were excluded at least partly because of an anatomically hostile proximal neck.
Table IV. Clinical outcomes of 12 patients excluded from thoracic endovascular aneurysm repair for both hostile proximal and hostile distal necks Outcome
n
TEVAR repair after LCCA-LSCA bypass TEVAR repair with partial occlusion of CA Open repair with left atrial-femoral artery bypass Refused open repair Not repaired
1 1 1 1 8
TEVAR, thoracic endovascular aneurysm repair; LCCA, left common carotid artery; LSCA, left subclavian artery; CA, celiac artery.
Excluded patients were then categorized by excluding anatomic feature(s). This analysis is best depicted in a Venn diagram (Fig 1). These different patient groups were analyzed according to clinical outcome. Three groups were of particular interest, and their anatomic characteristics and clinical outcomes are discussed here. First, the group excluded solely because of proximal neck anatomic features comprised nine patients with proximal descending TAAs. One of these patients underwent open repair with hypothermic circulatory arrest for an enlarging symptomatic aneurysm. Second, 12 patients comprising a cohort of patients with type I thoracoabdominal aortic aneurysms were excluded for a combination of proximal neck anatomy and distal neck anatomy,22 and their clinical outcomes are summarized in Table IV. One patient underwent TEVAR and required subsequent celiac axis stent placement because the thoracic aortic graft had partially covered the celiac ostium. Third, those patients excluded solely because of distal neck anatomic features represented patients with type V thoracoabdominal aortic aneurysms, arising at or below the 6th intercostal space and ending at or above the renal arteries.22 Two patients were in this category. One underwent open repair with left atrial-femoral arterial bypass for a large expanding aneurysm at our institution. The other underwent open repair at another institution for a symptomatic aneurysm.
Fig 2. Kaplan-Meier survival for those 25 patients who did not undergo operative repair at our institution.
Two patients who were initially excluded from TEVAR eventually underwent carotid–subclavian bypass and endografting (Table II). One was initially excluded because of a hostile proximal and distal neck anatomy, and the other was initially excluded because of narrow and calcified access vessel anatomy as well as hostile proximal neck anatomy. In the latter patient, access at operation was obtained through the left common iliac artery; at the conclusion of the procedure, this artery was narrowed at the site of arteriotomy repair and required stenting. Also as indicated in Table II, one patient underwent TEVAR after initially being excluded because of a hostile distal apposition site. At operation, the celiac artery ostium was unintentionally partially covered with the aortic stent, requiring celiac artery stenting at the conclusion of the procedure. The mean size of the TAAs in the 25 untreated patients was 6.3 cm (range, 4.0 to 9.6 cm). Survival of these untreated patients was analyzed using Kaplan-Meier statistics (Fig 2). As discussed, one patient underwent repair for symptoms at another institution and was censored from the analysis on the date of the surgery. Twelve patients died, and at least 3 of these deaths were attributed to aneurysm rupture. The mean survival was 3.8 years (95% confidence interval [CI], 2.7 to 4.9 years). In contrast, mean survival of the first 186 TAAs repaired endovascularly in an elective fashion at the same institution was 4.7 years (95% CI, 4.2 to 5.3 years) (Dr Wilson Y. Szeto, unpublished data, 2006). DISCUSSION This study is a retrospective analysis of 126 patients presenting for evaluation for repair of isolated TAA. It clearly demonstrates that most patients with aneurysms
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located between the LCCA and the CA are candidates for TEVAR repair. Aneurysm anatomic features resulted in 33 patients being excluded from the clinical trials of thoracic aortic stent grafts. Most had multiple anatomic features that would have made stent grafting difficult or impossible with currently available devices. The most common excluding anatomic feature was a hostile proximal neck. The hazards of TEVAR in patients with dilated, short apposition sites have been identified before, as has the need for branched designs to enable treatment of aneurysms involving or adjacent to the aortic arch and visceral segment. In 2003, Ellozy et al4 studied 84 patients receiving TEVAR and 101 patients undergoing open repair and identified three advances required to widen the applicability and extend the durability of thoracic stents: better proximal and distal fixation devices, better engineering to resist high thoracic aortic loads during and after deployment, and designs to accommodate aneurysms involving branched aortic segments. Likewise, Criado et al2 advocate “adjunctive surgical techniques designed to transpose arch branches” and thereby effectively lengthen the descending thoracic aorta. Whatever the approach, wider application of arch vessel bypass or transposition and wider availability and adoption of branched stent grafts will be necessary to allow repair of these TAAs. Distal neck anatomy can also provide significant technical challenges. As discussed, one patient with a relatively short distal neck closely approximated to the celiac access underwent TEVAR with unplanned partial coverage of the visceral vessel. The celiac axis was subsequently stented to reopen the ostium, but improved distal neck fixation or fenestrated and branched endograft technologies will allow more aggressive interventions in TAAs with hostile distal necks. Multiple authors have described or advocated combined or staged open surgical procedures and TEVAR for descending TAAs adjacent to or involving the visceral segment.9-11 Others have described modular, fenestrated, and branched stent graft systems for treatment of these challenging aneurysms entirely endovascularly.14,19 CONCLUSION The present analysis of clinical outcomes of these patients reveals that without suitable TEVAR technologies and techniques, these patients will likely not be candidates for any type of repair until and unless an emergency operation becomes necessary. Given the fairly large maximal diameters of these patients’ aneurysms and the relatively poor survival documented in those patients whose aneurysms were never repaired, our inability to safely and effectively treat these patients with TEVAR would be expected to have significant consequences insofar as the development of expansion, symptoms, and eventual rupture.
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AUTHOR CONTRIBUTIONS Conception and design: BJ, JC, RF, EW, JB Analysis and interpretation: BJ, JC, WM Data collection: BJ, WM, AP, EW, JB Writing the article: BJ, JC Critical revision of the article: JC, RF, WM, AP, EW, JB Final approval of the article: BJ, JC, RF, WM, AP, EW, JB Statistical analysis: BJ Obtained funding: JC, RF, JB Overall responsibility: BJ REFERENCES 1. Greenberg RK, O’Neill S, Walker E, Haddad F, Lyden SP, Svensson LG, et al. Endovascular repair of thoracic aortic lesions with the Zenith TX1 and TX2 thoracic grafts: intermediate-term results. J Vasc Surg 2005;41:589-96. 2. Criado FJ, Clark NS, Barnatan MF. Stent graft repair in the aortic arch and descending thoracic aorta: a 4-year experience. J Vasc Surg 2002; 36:1121-8. 3. Cambria RP, Brewster DC, Lauterbach SR, Kaufman JL, Geller S, Fan CM, et al. Evolving experience with thoracic aortic stent graft repair. J Vasc Surg 2002;35:1129-36. 4. Ellozy SH, Carroccio A, Minor M, Jacobs T, Chae K, Cha A, et al. Challenges of endovascular tube graft repair of thoracic aortic aneurysm: midterm follow-up and lessons learned. [See comment]. J Vasc Surg 2003;38:676-83. 5. Brandt M, Hussel K, Walluscheck KP, Muller-Hulsbeck S, Jahnke T, Rahimi A, et al. Stent-graft repair versus open surgery for the descending aorta: a case-control study. J Endovasc Ther 2004;11:535-8. 6. Karmacharya JJ, Woo EY, Fairman RM. Endovascular repair of a ruptured thoracic aortic aneurysm with the use of aortic extension cuffs. J Vasc Surg 2004;39:1128. 7. Kato N, Hirano T, Ishida M, Shimono T, Cheng SH, Yada I, et al. Acute and contained rupture of the descending thoracic aorta: treatment with endovascular stent grafts. J Vasc Surg 2003;37:100-5. 8. Doss M, Wood JP, Balzer J, Martens S, Deschka H, Moritz A. Emergency endovascular interventions for acute thoracic aortic rupture: four-year follow-up. J Thorac Cardiovasc Surg 2005;129:64551. 9. Flye MW, Choi ET, Sanchez LA, Curci JA, Thompson RW, Rubin BG, et al. Retrograde visceral vessel revascularization followed by endovascular aneurysm exclusion as an alternative to open surgical repair of thoracoabdominal aortic aneurysm. J Vasc Surg 2004;39: 454-8. 10. Watanabe Y, Ishimaru S, Kawaguchi S, Shimazaki T, Yokoi Y, Ito M, et al. Successful endografting with simultaneous visceral artery bypass grafting for severely calcified thoracoabdominal aortic aneurysm. J Vasc Surg 2002;35:397-9. 11. Quinones-Baldrich WJ, Panetta TF, Vescera CL, Kashyap VS. Repair of type IV thoracoabdominal aneurysm with a combined endovascular and surgical approach. J Vasc Surg 1999;30:555-60. 12. Czerny M, Zimpfer D, Fleck T, Hofmann W, Schoder M, Cejna M, et al. Initial results after combined repair of aortic arch aneurysms by sequential transposition of the supra-aortic branches and consecutive endovascular stent-graft placement. Ann Thorac Surg 2004;78: 1256-60. 13. Nitta Y, Tsuru Y, Yamaya K, Akasaka J, Oda K, Tabayashi K. Endovascular flexible stent grafting with arch vessel bypass for a case of aortic arch aneurysm. J Thorac Cardiovasc Surg 2003;126:1186-8. 14. Anderson JL, Adam DJ, Berce M, Hartley DE. Repair of thoracoabdominal aortic aneurysms with fenestrated and branched endovascular stent grafts. J Vasc Surg 2005;42:600-7. 15. Gottardi R, Seitelberger R, Zimpfer D, Lammer J, Wolner E, Grimm M, et al. An alternative approach in treating an aortic arch aneurysm with an anatomic variant by supraaortic reconstruction and stent-graft placement. J Vasc Surg 2005;42:357-60.
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16. Saito N, Kimura T, Odashiro K, Toma M, Nobuyoshi M, Ueno K, et al. Feasibility of the Inoue single-branched stent-graft implantation for thoracic aortic aneurysm or dissection involving the left subclavian artery: short- to medium-term results in 17 patients. J Vasc Surg 2005;41:206-12. 17. Chuter TA, Schneider DB, Reilly LM, Lobo EP, Messina LM. Modular branched stent graft for endovascular repair of aortic arch aneurysm and dissection. J Vasc Surg 2003;38:859-63. 18. Schneider DB, Curry TK, Reilly LM, Kang JW, Messina LM, Chuter TA. Branched endovascular repair of aortic arch aneurysm with a modular stent-graft system. J Vasc Surg 2003;38:855. 19. Bleyn J, Schol F, Vanhandenhove I, Vercaeren P. Side-branched modular endograft system for thoracoabdominal aortic aneurysm repair. J Endovasc Ther 2002;9:838-41.
20. Chuter TA, Gordon RL, Reilly LM, Goodman JD, Messina LM. An endovascular system for thoracoabdominal aortic aneurysm repair. [See comment]. J Endovasc Ther 2001;8:25-33. 21. Inoue K, Iwase T, Sato M, Yoshida Y, Ueno K, Tamaki S, et al. Transluminal endovascular branched graft placement for a pseudoaneurysm: reconstruction of the descending thoracic aorta including the celiac axis. J Thorac Cardiovasc Surg 1997;114:859-61. 22. Safi HJ, Miller CC 3rd, Estrera AL, Huynh TT, Rubenstein FS, Subramaniam MH, et al. Staged repair of extensive aortic aneurysms: morbidity and mortality in the elephant trunk technique. Circulation 2001;104:2938-42.
Submitted Mar 13, 2006; accepted Dec 22, 2006.
COLLECTIONS OF PAPERS On the Web version of the Journal, selected articles have been grouped together for the convenience of the readers. The current collections include the following: American Board of Vascular Surgery Editorial Comments History Reporting Standards Technical Notes
Basic Science Reviews Guidelines Lifeline Research Meeting Abstracts Reviews
Anatomic exclusion from endovascular repair of thoracic aortic aneurysm Benjamin M. Jackson, MD, Jeffrey P. Carpenter, MD, Ronald M. Fairman, MD, G. William Moser, MSN, RN, Alberto Pochettino, MD, Edward Y. Woo, MD, and Joseph E. Bavaria, MD, Philadelphia, Pa Objectives: We sought to define the current anatomic barriers to thoracic aortic aneurysm (TAA) stent grafting to guide future device development. Methods: All patients presenting with TAA requiring repair were evaluated for endovascular repair during a 4-year period (2000 to 2004). The TAAs evaluated were those beginning distal to the left common carotid artery (LCCA) and ending proximal to the celiac artery. All patients in whom endovascular repair was indicated underwent cross-sectional imaging by computed tomography angiography and three-dimensional modeling of their thoracic and abdominal arterial anatomy. Patients were evaluated for endovascular TAA repair in the context of the inclusion/exclusion criteria of pivotal United States Food and Drug Administration trials of the Gore TAG and Medtronic Talent devices. Anatomic requirements included >20 mm of suitable proximal and distal neck length, and proximal and distal neck diameters of 20 to 42 mm. These trials allowed the use of femoral or iliac access, including the use of conduits, and permitted stent graft coverage of the left subclavian artery (LSA) after preliminary carotid–subclavian bypass. Patients rejected for medical reasons or who died during evaluation were not included in the review. Results: A total of 126 patients (73 men, 53 women) with TAA located between the LCCA and celiac artery were screened for endovascular repair, and 33 (26%) were rejected for anatomic reasons. The remaining 93 patients underwent endografting (59 Talent, 34 TAG). Rejection was not significantly different by gender (16/73 men, 17/53 women, P ⴝ .22, NS). Most patients (28/33) were rejected for more than one criterion. Hostile proximal neck characteristics were the most prevalent reason for disqualification, despite the ability to cover the LSA to extend the proximal seal zone. Many of these patients (16/28) also had distal neck anatomy unsuitable for grafting. Overall, 19 patients had hostile distal necks. Difficulties with vascular access (diseased or tortuous iliac arteries, or a small caliber aorta) that could not be overcome even by use of conduits occurred in a significant fraction of patients (10/33). Conclusions: Most patients with a TAA located between the LCCA and the celiac artery can be treated by endovascular repair. Patients excluded from TAA stent graft protocols for anatomic reasons most commonly have hostile proximal neck features that preclude endovascular repair with currently available devices. Transposition of arch vessels to facilitate greater use of existing stent grafts or development of new stent graft designs are needed to expand the applicability of TAA endovascular repair. ( J Vasc Surg 2007;45:662-6.)
Thoracic aortic aneurysms (TAAs) are currently being treated, with much success, by using stent grafting1-3; however, not all patients with TAAs are eligible for these lessinvasive endovascular repairs. Proximal and distal fixation and involvement of aortic branches in aneurysmal segments have been identified as barriers to more widespread application of thoracic endovascular aneurysm repair (TEVAR).4 The analysis of anatomic features of aneurysms that make endovascular repair challenging or impossible will guide the development of the next generation of devices. Open repair of TAAs carries significant risks of morbidity and mortality, including pulmonary and cardiac complications, bleeding, wound problems, and neurovascular compromise. Although endografting does not eliminate all of these risks, it is associated with significantly smaller perioperative From the Hospital of the University of Pennsylvania. Competition of interest: none. Presented at the 2006 Annual Symposium of the Society for Clinical Vascular Surgery, Las Vegas, Nev, March 8-11, 2006. Correspondence: Dr Benjamin M. Jackson, 4 Maloney Building, Department of Surgery, Hospital of the University of Pennsylvania, 3400 Spruce St, Philadelphia, PA 19130 (e-mail: [email protected]). 0741-5214/$32.00 Copyright © 2007 by The Society for Vascular Surgery. doi:10.1016/j.jvs.2006.12.062
662
mortality and a shorter hospital stay.5 Contained ruptures of TAAs have likewise been successfully treated using TEVAR,6-8 expanding the applicability of the technique but further straining the existing approved devices. Many TAAs cannot be stented without coverage of branch vessels. Extra-anatomic bypass of visceral vessels, followed by TEVAR, has been required given the limitations of currently available stents.9-11 Arch vessel bypass has been widely used to treat aortic arch aneurysms using TEVAR.12,13 Treatment of thoracoabdominal and aortic arch aneurysms with fenestrated and branched endografts is being more widely accepted and applied.14-21 In an attempt to delineate the limitations of the current generation of endografts, better define the needed design elements in the next generation, and assess the proportion of patients with TAA who will not be treatable with current endografts, we examined isolated descending TAAs, identifying those patients who were excluded from clinical trials for widely used thoracic endografts because of hostile anatomic features. METHODS Study design. We identified all patients evaluated for endovascular repair of isolated TAA at the Hospital of the
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Table I. Exclusion criteria for sponsored, controlled clinical trials Gore TAG
Medtronic Talent
*Nonaneurysmal segment at either neck ⬍2 cm Diameter at either neck ⬍23 mm or ⬎37 mm Occluded LCCA or CA “Significant thrombus” at either neck Proximal neck angulated ⬍60° Taper at either neck ⬎ 4 mm
*Nonaneurysmal segment at either neck ⬍2 cm Diameter at either neck ⬍18 mm or ⬎42 mm Clearance at LCCA or CA ⬍20 mm “Significant mural thrombus” at either neck Access vessel “precludes safe insertion of delivery system
LCCA, Left common carotid artery; CA, celiac artery. *Including, where necessary, the segment involving the takeoff of the left subclavian artery.
Table II. Clinical outcomes of the 33 patients excluded from endovascular stent grafting
Table III. Rejection criteria for all 33 patients, in compendium
Outcome
n
Criteria
n
TEVAR after LCCA-LSCA bypass TEVAR with partial occlusion of CA Open repair with left atrial-femoral artery bypass Open repair with hypothermic circulatory arrest Not repaired at this institution
2 1 3 2 25
Short proximal neck
16 Proximal neck anatomy 10 6 2 9 2 7 Distal neck anatomy 5 1 13 9 Access anatomy 1 1
TEVAR, thoracic endovascular aneurysm repair; LCCA, left common carotid artery; LSCA, left subclavian artery; CA, celiac artery.
University of Pennsylvania between 2000 and 2004. Patients with aneurysmal segments proximal to the left common carotid artery (LCCA) or distal to the celiac axis were not included in this study. All patients in whom TEVAR was indicated underwent cross-sectional imaging by computed tomography angiogram and subsequent threedimensional modeling by Medical Metrix Solutions (MMS, West Lebanon, NH). All patients were evaluated for either the Gore TAG endoprosthesis (W. L. Gore & Associates, Flagstaff, Ariz) or the Medtronic Talent graft (Medtronic, Minneapolis, Minn), or both. Patients were excluded from TEVAR repair on the clinical judgment of the surgeons participating in the trials, who were familiar with the anatomic exclusion criteria defined by the controlled clinical trials sponsored for the two devices (Table I). After each patient’s anatomy was analyzed, the excluding features were grouped according to broad categories: hostile proximal neck, hostile distal neck, or inadequate access vessels. Outcomes and follow-up. All patients initially rejected for TEVAR repair of a TAA for anatomic reasons were followed up to assess clinical outcome and eventual open or endovascular repair. Statistical analysis. All statistical calculations were performed by using SPSS software (SPSS Inc, Chicago, Ill). The Fisher exact test with a two-tailed assumption was used to assess for gender-based differences in rejection for TEVAR and for gender-based differences in the anatomic features leading to exclusion. Data are presented as mean ⫾ standard deviation, unless otherwise indicated. KaplanMeier statistics were used to analyze survival of the untreated patients.
Wide proximal neck Excessive proximal taper Angulated proximal neck Proximal neck thrombus Proximal neck calcification Short distal neck Wide distal neck Excessive distal taper Distal neck thrombus Narrow or tortuous iliac arteries Iliac occlusive disease Narrow aorta
Category
n 28
19
10
RESULTS Between 2000 and 2004, 126 patients (73 men and 53 women) with isolated TAA were evaluated (P ⫽ .05), and 33 (26%; 16 men, 17 women, P ⫽ .22) were rejected for TEVAR on anatomic grounds. These patients were generally ⬎70 years old (25, 75%), their aneurysms were of significant size, 6.4 ⫾ 1.4 cm, and most (85%) were excluded for meeting more than one criterion (mean, 2.5 ⫾ 1.2 criteria). Clinical outcomes for those patients excluded from TEVAR are summarized in Table II. Of the 33 patients excluded, 25 did not undergo repair of their aneurysms at our institution owing to some combination of relatively small aneurysms, medical unsuitability for open operation, and patient unwillingness to undergo open repair. The exclusion criteria were grouped according to category: 28 patients had hostile proximal neck anatomy, 19 had hostile distal neck anatomy, and 10 had access anatomy making TEVAR difficult or impossible. Both the specific excluding anatomic features and their broad categorization are presented in Table III. There was no gender-based difference in proportion of aneurysms with hostile proximal necks (13 men and 15 women, P ⫽ .66), hostile distal necks (11 men and 8 women, P ⫽ .29), or both (9 men and 7 women, P ⫽ .49). Women had a tendency toward being more likely to have difficult access anatomy (3 men and 7 women, P ⫽ .25), but this difference did not reach statistical significance.
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Fig 1. A Venn diagram demonstrates the clustering of patients according to exclusion criteria category. Note that fully 28 of 33 patients were excluded at least partly because of an anatomically hostile proximal neck.
Table IV. Clinical outcomes of 12 patients excluded from thoracic endovascular aneurysm repair for both hostile proximal and hostile distal necks Outcome
n
TEVAR repair after LCCA-LSCA bypass TEVAR repair with partial occlusion of CA Open repair with left atrial-femoral artery bypass Refused open repair Not repaired
1 1 1 1 8
TEVAR, thoracic endovascular aneurysm repair; LCCA, left common carotid artery; LSCA, left subclavian artery; CA, celiac artery.
Excluded patients were then categorized by excluding anatomic feature(s). This analysis is best depicted in a Venn diagram (Fig 1). These different patient groups were analyzed according to clinical outcome. Three groups were of particular interest, and their anatomic characteristics and clinical outcomes are discussed here. First, the group excluded solely because of proximal neck anatomic features comprised nine patients with proximal descending TAAs. One of these patients underwent open repair with hypothermic circulatory arrest for an enlarging symptomatic aneurysm. Second, 12 patients comprising a cohort of patients with type I thoracoabdominal aortic aneurysms were excluded for a combination of proximal neck anatomy and distal neck anatomy,22 and their clinical outcomes are summarized in Table IV. One patient underwent TEVAR and required subsequent celiac axis stent placement because the thoracic aortic graft had partially covered the celiac ostium. Third, those patients excluded solely because of distal neck anatomic features represented patients with type V thoracoabdominal aortic aneurysms, arising at or below the 6th intercostal space and ending at or above the renal arteries.22 Two patients were in this category. One underwent open repair with left atrial-femoral arterial bypass for a large expanding aneurysm at our institution. The other underwent open repair at another institution for a symptomatic aneurysm.
Fig 2. Kaplan-Meier survival for those 25 patients who did not undergo operative repair at our institution.
Two patients who were initially excluded from TEVAR eventually underwent carotid–subclavian bypass and endografting (Table II). One was initially excluded because of a hostile proximal and distal neck anatomy, and the other was initially excluded because of narrow and calcified access vessel anatomy as well as hostile proximal neck anatomy. In the latter patient, access at operation was obtained through the left common iliac artery; at the conclusion of the procedure, this artery was narrowed at the site of arteriotomy repair and required stenting. Also as indicated in Table II, one patient underwent TEVAR after initially being excluded because of a hostile distal apposition site. At operation, the celiac artery ostium was unintentionally partially covered with the aortic stent, requiring celiac artery stenting at the conclusion of the procedure. The mean size of the TAAs in the 25 untreated patients was 6.3 cm (range, 4.0 to 9.6 cm). Survival of these untreated patients was analyzed using Kaplan-Meier statistics (Fig 2). As discussed, one patient underwent repair for symptoms at another institution and was censored from the analysis on the date of the surgery. Twelve patients died, and at least 3 of these deaths were attributed to aneurysm rupture. The mean survival was 3.8 years (95% confidence interval [CI], 2.7 to 4.9 years). In contrast, mean survival of the first 186 TAAs repaired endovascularly in an elective fashion at the same institution was 4.7 years (95% CI, 4.2 to 5.3 years) (Dr Wilson Y. Szeto, unpublished data, 2006). DISCUSSION This study is a retrospective analysis of 126 patients presenting for evaluation for repair of isolated TAA. It clearly demonstrates that most patients with aneurysms
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located between the LCCA and the CA are candidates for TEVAR repair. Aneurysm anatomic features resulted in 33 patients being excluded from the clinical trials of thoracic aortic stent grafts. Most had multiple anatomic features that would have made stent grafting difficult or impossible with currently available devices. The most common excluding anatomic feature was a hostile proximal neck. The hazards of TEVAR in patients with dilated, short apposition sites have been identified before, as has the need for branched designs to enable treatment of aneurysms involving or adjacent to the aortic arch and visceral segment. In 2003, Ellozy et al4 studied 84 patients receiving TEVAR and 101 patients undergoing open repair and identified three advances required to widen the applicability and extend the durability of thoracic stents: better proximal and distal fixation devices, better engineering to resist high thoracic aortic loads during and after deployment, and designs to accommodate aneurysms involving branched aortic segments. Likewise, Criado et al2 advocate “adjunctive surgical techniques designed to transpose arch branches” and thereby effectively lengthen the descending thoracic aorta. Whatever the approach, wider application of arch vessel bypass or transposition and wider availability and adoption of branched stent grafts will be necessary to allow repair of these TAAs. Distal neck anatomy can also provide significant technical challenges. As discussed, one patient with a relatively short distal neck closely approximated to the celiac access underwent TEVAR with unplanned partial coverage of the visceral vessel. The celiac axis was subsequently stented to reopen the ostium, but improved distal neck fixation or fenestrated and branched endograft technologies will allow more aggressive interventions in TAAs with hostile distal necks. Multiple authors have described or advocated combined or staged open surgical procedures and TEVAR for descending TAAs adjacent to or involving the visceral segment.9-11 Others have described modular, fenestrated, and branched stent graft systems for treatment of these challenging aneurysms entirely endovascularly.14,19 CONCLUSION The present analysis of clinical outcomes of these patients reveals that without suitable TEVAR technologies and techniques, these patients will likely not be candidates for any type of repair until and unless an emergency operation becomes necessary. Given the fairly large maximal diameters of these patients’ aneurysms and the relatively poor survival documented in those patients whose aneurysms were never repaired, our inability to safely and effectively treat these patients with TEVAR would be expected to have significant consequences insofar as the development of expansion, symptoms, and eventual rupture.
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AUTHOR CONTRIBUTIONS Conception and design: BJ, JC, RF, EW, JB Analysis and interpretation: BJ, JC, WM Data collection: BJ, WM, AP, EW, JB Writing the article: BJ, JC Critical revision of the article: JC, RF, WM, AP, EW, JB Final approval of the article: BJ, JC, RF, WM, AP, EW, JB Statistical analysis: BJ Obtained funding: JC, RF, JB Overall responsibility: BJ REFERENCES 1. Greenberg RK, O’Neill S, Walker E, Haddad F, Lyden SP, Svensson LG, et al. Endovascular repair of thoracic aortic lesions with the Zenith TX1 and TX2 thoracic grafts: intermediate-term results. J Vasc Surg 2005;41:589-96. 2. Criado FJ, Clark NS, Barnatan MF. Stent graft repair in the aortic arch and descending thoracic aorta: a 4-year experience. J Vasc Surg 2002; 36:1121-8. 3. Cambria RP, Brewster DC, Lauterbach SR, Kaufman JL, Geller S, Fan CM, et al. Evolving experience with thoracic aortic stent graft repair. J Vasc Surg 2002;35:1129-36. 4. Ellozy SH, Carroccio A, Minor M, Jacobs T, Chae K, Cha A, et al. Challenges of endovascular tube graft repair of thoracic aortic aneurysm: midterm follow-up and lessons learned. [See comment]. J Vasc Surg 2003;38:676-83. 5. Brandt M, Hussel K, Walluscheck KP, Muller-Hulsbeck S, Jahnke T, Rahimi A, et al. Stent-graft repair versus open surgery for the descending aorta: a case-control study. J Endovasc Ther 2004;11:535-8. 6. Karmacharya JJ, Woo EY, Fairman RM. Endovascular repair of a ruptured thoracic aortic aneurysm with the use of aortic extension cuffs. J Vasc Surg 2004;39:1128. 7. Kato N, Hirano T, Ishida M, Shimono T, Cheng SH, Yada I, et al. Acute and contained rupture of the descending thoracic aorta: treatment with endovascular stent grafts. J Vasc Surg 2003;37:100-5. 8. Doss M, Wood JP, Balzer J, Martens S, Deschka H, Moritz A. Emergency endovascular interventions for acute thoracic aortic rupture: four-year follow-up. J Thorac Cardiovasc Surg 2005;129:64551. 9. Flye MW, Choi ET, Sanchez LA, Curci JA, Thompson RW, Rubin BG, et al. Retrograde visceral vessel revascularization followed by endovascular aneurysm exclusion as an alternative to open surgical repair of thoracoabdominal aortic aneurysm. J Vasc Surg 2004;39: 454-8. 10. Watanabe Y, Ishimaru S, Kawaguchi S, Shimazaki T, Yokoi Y, Ito M, et al. Successful endografting with simultaneous visceral artery bypass grafting for severely calcified thoracoabdominal aortic aneurysm. J Vasc Surg 2002;35:397-9. 11. Quinones-Baldrich WJ, Panetta TF, Vescera CL, Kashyap VS. Repair of type IV thoracoabdominal aneurysm with a combined endovascular and surgical approach. J Vasc Surg 1999;30:555-60. 12. Czerny M, Zimpfer D, Fleck T, Hofmann W, Schoder M, Cejna M, et al. Initial results after combined repair of aortic arch aneurysms by sequential transposition of the supra-aortic branches and consecutive endovascular stent-graft placement. Ann Thorac Surg 2004;78: 1256-60. 13. Nitta Y, Tsuru Y, Yamaya K, Akasaka J, Oda K, Tabayashi K. Endovascular flexible stent grafting with arch vessel bypass for a case of aortic arch aneurysm. J Thorac Cardiovasc Surg 2003;126:1186-8. 14. Anderson JL, Adam DJ, Berce M, Hartley DE. Repair of thoracoabdominal aortic aneurysms with fenestrated and branched endovascular stent grafts. J Vasc Surg 2005;42:600-7. 15. Gottardi R, Seitelberger R, Zimpfer D, Lammer J, Wolner E, Grimm M, et al. An alternative approach in treating an aortic arch aneurysm with an anatomic variant by supraaortic reconstruction and stent-graft placement. J Vasc Surg 2005;42:357-60.
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20. Chuter TA, Gordon RL, Reilly LM, Goodman JD, Messina LM. An endovascular system for thoracoabdominal aortic aneurysm repair. [See comment]. J Endovasc Ther 2001;8:25-33. 21. Inoue K, Iwase T, Sato M, Yoshida Y, Ueno K, Tamaki S, et al. Transluminal endovascular branched graft placement for a pseudoaneurysm: reconstruction of the descending thoracic aorta including the celiac axis. J Thorac Cardiovasc Surg 1997;114:859-61. 22. Safi HJ, Miller CC 3rd, Estrera AL, Huynh TT, Rubenstein FS, Subramaniam MH, et al. Staged repair of extensive aortic aneurysms: morbidity and mortality in the elephant trunk technique. Circulation 2001;104:2938-42.
Submitted Mar 13, 2006; accepted Dec 22, 2006.
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