- Email: [email protected]
Endovascular aneurysm repair (EVAR)
international journal of surgery 6 (2008) 266–269
www.theijs.com
Review
Endovascular aneurysm repair (EVAR) Shameen Jaunoo Department of General & Vascular Surgery, University Hospital of North Staffordshire, Newcastle Road, Stoke-on-Trent, Staffordshire, ST4-6QG, UK
article info
abstract
Article history:
Endovascular repair of an abdominal aortic aneurysm (AAA) is an evolving technology
Received 19 January 2008
which continues to be practiced in more and more centres worldwide in an effort to avoid
Accepted 1 February 2008
major abdominal surgery and its associated morbidity and mortality. As with conventional
Published online 8 February 2008
open surgery, the objective of endovascular management is to provide a durable repair maintaining antegrade flow in the graft whilst simultaneously excluding flow in the aneu-
Keywords:
rysm. Endovascular treatment offers a less invasive alternative to standard surgical repair
Endovascular aneurysm repair
with the potential of reduced hospitalisation, morbidity and mortality. ª 2008 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.
EVAR Abdominal aortic aneurysm AAA
1.
Introduction
The natural history of an abdominal aortic aneurysm (AAA) is progressive enlargement until the aortic wall is so weakened that it ruptures causing internal haemorrhaging. Most centres report mortality rates from ruptured AAA’s of around 50% (ranging from 32 to 70%).1–4 However, the overall mortality, once rupture has occurred, approaches 90%.1,3 Therefore, the primary objective in the treatment of a diagnosed AAA is to prevent death from rupture which is the 3rd most common cause of sudden death in the U.K. after coronary artery disease and stroke. Once an asymptomatic AAA is found, the most important question becomes the probability of rupture. This probability correlates well with the size of the aneurysm at initial detection (usually ultrasound) and is directly related to the aneurysm’s diameter. Rupture rates are typically 25–40% at 5 years for aneurysms greater than 5 cm in diameter, 5–7% for those 3.5–5.0 cm, and approach 0% for aneurysms less than 3.5 cm.5 The management options for an unruptured abdominal aortic aneurysm previously included conventional ‘open’
repair and watchful waiting (encompassing regular ultrasonic surveillance and optimisation of medical risk factors). Standard surgical repair, involving a large abdominal incision and cross-clamping of the aorta, is frequently complicated by the high likelihood of associated comorbidities and has an average mortality of approximately 2% increasing to 6% in higher risk patients.6 With an ageing population, the number of high risk cases also increases. Average blood loss is 2–3 units in 95% of cases with an average hospital stay of 6 days.5,6 In recent years, a new minimally invasive technique, endovascular aneurysm repair (EVAR), has been developed and incorporated into the management options for the elective repair of an infrarenal AAA as an alternative to conventional surgery.
2.
Endovascular aneurysm repair (EVAR)
EVAR was invented in the early 1990s by surgeons in the Ukraine and Argentina as a less invasive method of AAA
E-mail address: [email protected] 1743-9191/$ – see front matter ª 2008 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.ijsu.2008.02.001
international journal of surgery 6 (2008) 266–269
repair. Improvement of the devices and development of the technology have led EVAR to be used worldwide. Endovascular aneurysm repair involves the transfemoral or transiliac placement of an endograft within the aneurysm via two small incisions made in the patient’s groin. The aim being the complete exclusion of the aneurysm sac from the circulation. The endograft is anchored in place by self-expanding or balloonexpandable stents, which may support all or part of the graft. Endovascular grafts fall into three broad categories: (i) bifurcated or tubular unibody grafts (ii) modular multicomponent grafts (iii) aorto unilateral grafts with a contralateral iliac occluder which are followed by surgical femoro-femoral bypass7
- Dissection of the aortic neck may cause damage to the renal, adrenal, lumbar and gonadal veins - Aortic cross-clamping increases cardiac stress with increased cardiac afterload. It also leads to visceral and renal ischaemia (after suprarenal clamping), and lower limb ischaemia with the systemic complications of ischaemiareperfusion injury Two recent randomised trials12,13 have reported a twothirds reduction in the 30-day mortality rate with elective EVAR compared with conventional open surgery (1.6% and 1.2% for EVAR compared with 4.6% and 6% for open repair).
2.3. 2.1.
Anatomical suitability
The eligibility of a patient with an infrarenal AAA for endovascular repair relies on certain anatomical requirements for complete aneurysm exclusion. Aneurysms that rupture are associated with larger diameters than their intact counterparts. It has been suggested that larger aneurysms have more adverse morphological features which may increase the technical difficulty and therefore reduce the applicability of the endovascular technique. Several authors, however, have reported the applicability of EVAR in approximately 60% of AAA’s.8–10 Contrast-enhanced spiral CT has become the investigation of choice in the assessment of elective AAA for EVAR.11 Occasionally, angiography is also used. Generally speaking, the anatomical determinations which must be made in planning graft implantation are: - diameter and length of the infrarenal aorta and neck of the aorta - diameter and length of the iliac attachments (‘landing zones’) - tortuosity and size of the access vessels - critical vessel anatomy
Criteria of eligibility for EVAR -
2.2.
Neck length 15 mm Neck diameter < 30 mm Neck angulation < 60–80 Iliac diameter 7 mm
Advantages of EVAR
267
Complications of EVAR
EVAR is not without its complications and these differ substantially from those encountered with open repair. The majority of complications are related to the procedure itself. Early complications (<30 days) include: - wound complications: infection, haematomas, lymphoceles - arterial access complications: arterial perforation, rupture, dissection and plaque embolisation, pseudoaneurysm formation - renal ostia coverage - hypogastric artery embolisation complications: buttock claudication, gluteal myonecrosis and renal failure - endoleaks - endograft limb occlusion/thrombosis - systemic complications: despite EVAR resulting in fewer systemic complications than open surgical repair, these complications still represent the most frequent complication in the post-procedure period. The range of complications includes cardiac and pulmonary dysfunction, renal failure, embolic phenomena and spinal cord ischaemia Late complications: these are typically diagnosed on imaging studies for graft surveillance. The common routine is a CT scan at 1, 6 and 12 months post-procedure, and annually thereafter. Late complications include: -
Certain problems associated with conventional open repair of AAA, and thus contributing to morbidity and mortality, that are avoided by EVAR include the following:
-
- Open repair requires general anaesthetic - Laparotomy, third space fluid losses, ileus, postoperative ventilatory impairment, urinary retention, delayed mobility, prolonged hospitalisation
-
wound complications: lymphoceles and pseudoan-eurysms endoleaks endograft limb occlusion/thrombosis graft migration neck dilatation sac expansion endotension: defined as an increase in sac pressure without the presence of an endoleak graft infection aortoduodenal fistula implant-related complications: hook fractures, modular component separation and fabric erosion systemic complications: very few occur in the late period. The surveillance regimen of serial CT scans with intravenous contrast can, in certain patients, lead to contrastinduced nephropathy
268
2.4.
international journal of surgery 6 (2008) 266–269
Endoleaks
A problem unique to EVAR is endoleaks which describe ‘‘the inability to obtain or maintain a secure seal between the aortic wall and a transluminally implanted intra-aneurysmal graft’’.14 In essence, endoleaks are the presence of flow outside the lumen of the endograft but within the aneurysm sac. They increase the risk of aneurysm rupture and are the primary reason for such close surveillance following the procedure. The rate of endoleak following endovascular repair of AAA is approximately 14%.15 There are four types; Type I – anastomotic at the attachment sites; Type II – collateral back bleeding into the aneurysm sac; Type III – modular dissociation; Type IV – graft material porosity. Each type of endoleak can be noted during the procedure or surveillance period and all endoleaks may not be of equal significance. Both Type I (attachment site) and Type III (modular limb dislocation or graft fabric failure) are significant risk factors for late aneurysm rupture.16 In contrast, Type II endoleaks are generally considered as benign with only isolated cases of aneurysm expansion and rupture.17 Type IV endoleaks usually resolve spontaneously during the post-procedure period.
Classification of endoleaks I Attachment site leaks
- Proximal end of endograft - Distal end of endograft - Iliac occluder (plug) II Branch leaks (without attachment site connection)
- Simple or to-and-fro (from only one patent branch) - Complex or flow-through (with two or more patent branches) III Graft defect
- Junctional leak or modular disconnection - Fabric disruption (mid-graft hole) Minor (<2 mm, e.g. suture holes) Major (2 mm) IV Graft wall (fabric) porosity (<30 days after graft placement)
3.
Conclusion
Since Parodi undertook the first endograft repair of an AAA in 1990, there has been great excitement.18 The new treatment and technologies created much optimism and anticipation which must now be tempered by clinical experience and practical considerations. EVAR is currently constrained by both technical limitations and patient selection criteria and consequently, is not applicable to many patients with AAA. EVAR requires significant commitments from the participating physicians and the facilities in both time and logistical support. The promise of decreasing mortalities and shortened hospital stays are countered by the extremely high
cost of devices and the application of aneurysm repair to a higher risk patient population. Large delivery catheters exclude many women whose small iliac arteries will not accommodate such devices. EVAR is an exciting but demanding technology which holds great promise. The hope for the future is less costly, smaller profile devices with wider applicability, improved stability and fixation, and the elimination of endoleaks providing a durable repair comparable to a surgical graft. Continued research and development are needed in order to make EVAR an exclusively percutaneous procedure and attain these goals, thus improving patient care.
Conflicts of interest None declared.
references
1. Johansen K, Kohler TR, Nicholls SC, Zierler RE, Clowes AW, Kazmers A. Ruptured abdominal aortic aneurysms: the Harbour view experience. J Vasc Surg 1991;13:240–7. 2. Kniemeyer HW, Kessler T, Reber PU, Ris HB, Hakki H, Widmer MK. Treatment of ruptured abdominal aortic aneurysms: a permanent challenge or waste of resources? Prediction of outcome using multi-organ dysfunction score. Eur J Vasc Endovasc Surg 2000;19:190–6. 3. Noel AA, Gloviczki P, Cherry Jr KJ, Bower TC, Panneton JM, Mozes GI, et al. Ruptured abdominal aortic aneurysms: the excessive mortality rate of conventional repair. J Vasc Surg 2001;34:41–6. 4. Heller JA, Weinberg A, Arons R, Krishnasastry KV, Lyon RT, Deitch JS, et al. Two decades of aortic abdominal aneurysm repair: have we made any progress? J Vasc Surg 2000;32: 1091–100. 5. Wyffels P. Abdominal aortic aneurysms: natural history and surgical treatment. In: Dolmath B, Blum U, editors. Stent grafts: current clinical practice; 2000. p. 43–54. 6. Hollier LH, Reigel MM, Kazmier FJ, Pairolero PC, Cherry KJ, Hallett Jr JW. Conventional repair of abdominal aortic aneurysm in the high-risk patient: a plea for abandonment of non-resective treatment. J Vasc Surg 1986;3:712. 7. Veith F. History potential influence and facility requirements of transluminally placed endovascular grafts. In: Parodi JA, Veith F, Marin M, editors. Endovascular grafting techniques. Philadelphia: William and Wilkins; 1999. p. 1–5. 8. Armon MP, Yusuf SW, Latief K, Whitaker SC, Gregson RH, Wenham PW, et al. Anatomical suitability of abdominal aortic aneurysms for endovascular repair. Br J Surg 1997;84:178–80. 9. Woodburn KR, Chant H, Davies JN, Blanshard KS, Travis SJ. Suitability for endovascular aneurysm repair in an unselected population. Br J Surg 2001;88:77–81. 10. Bayle O, Branchereau A, Rosset E, Guillemot E, Beaurain P, Ferdani M, et al. Morphologic assessment of abdominal aortic aneurysms by spiral computed tomographic scanning. J Vasc Surg 1997;26:238–46. 11. Willmann JK, Lachat ML, von Smekal A, Turina MI, Pfammatter T. Spiral-CT angiography to assess feasibility of endovascular aneurysm repair in patients with ruptured aorto-iliac aneurysm. VASA 2001;30:271–6. 12. Greenhalgh RM, Brown LC, Kwong GP, Powell GT, Thompson SG. Comparison of endovascular aneurysm repair with open repair in patients with abdominal aortic aneurysm (EVAR Trial 1), 30 day operative mortality results: randomised control trial. Lancet 2004;364:843–8.
international journal of surgery 6 (2008) 266–269
13. Prinssen M, Verhoeven EL, Buth J, Cuypers PW, van Sambeek MR, Balm R, et al. A randomised trial comparing conventional and endovascular repair of abdominal aortic aneurysms. N Engl J Med 2004;351:1607–18. 14. White GH, Yu W, May J. Endoleak – a proposed new terminology to describe incomplete aneurysm exclusion by an endoluminal graft [letter]. J Endovasc Surg 1996;3:124–5. 15. Wain RA, Marin ML, Ohki T, Sanchez LA, Lyon RT, Rozenblit A, et al. Endoleaks as a complication of endovascular treatment of aortic aneurysms: classification, risk factors and outcome. J Vasc Surg 1998;27:69.
269
16. van Marrewijk C, Buth J, Harris PL, Norgren L, Nevelsteen A, Wyatt MG. Significance of endoleaks after endovascular repair of abdominal aortic aneurysms: the EUROSTAR experience. J Vasc Surg 2002;35:461–73. 17. Hinchliffe RJ, Singh-Ranger R, Davidson IR, Hopkinson BR. Rupture of an abdominal aortic aneurysm secondary to type II endoleak. Eur J Vasc Endovasc Surg 2001;22: 563–5. 18. Parodi JC, Palmaz JC, Barone HD. Transfemoral intraluminal graft implantation for abdominal aortic aneurysms. Ann Vasc Surg 1991;5:491–6.
www.theijs.com
Review
Endovascular aneurysm repair (EVAR) Shameen Jaunoo Department of General & Vascular Surgery, University Hospital of North Staffordshire, Newcastle Road, Stoke-on-Trent, Staffordshire, ST4-6QG, UK
article info
abstract
Article history:
Endovascular repair of an abdominal aortic aneurysm (AAA) is an evolving technology
Received 19 January 2008
which continues to be practiced in more and more centres worldwide in an effort to avoid
Accepted 1 February 2008
major abdominal surgery and its associated morbidity and mortality. As with conventional
Published online 8 February 2008
open surgery, the objective of endovascular management is to provide a durable repair maintaining antegrade flow in the graft whilst simultaneously excluding flow in the aneu-
Keywords:
rysm. Endovascular treatment offers a less invasive alternative to standard surgical repair
Endovascular aneurysm repair
with the potential of reduced hospitalisation, morbidity and mortality. ª 2008 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.
EVAR Abdominal aortic aneurysm AAA
1.
Introduction
The natural history of an abdominal aortic aneurysm (AAA) is progressive enlargement until the aortic wall is so weakened that it ruptures causing internal haemorrhaging. Most centres report mortality rates from ruptured AAA’s of around 50% (ranging from 32 to 70%).1–4 However, the overall mortality, once rupture has occurred, approaches 90%.1,3 Therefore, the primary objective in the treatment of a diagnosed AAA is to prevent death from rupture which is the 3rd most common cause of sudden death in the U.K. after coronary artery disease and stroke. Once an asymptomatic AAA is found, the most important question becomes the probability of rupture. This probability correlates well with the size of the aneurysm at initial detection (usually ultrasound) and is directly related to the aneurysm’s diameter. Rupture rates are typically 25–40% at 5 years for aneurysms greater than 5 cm in diameter, 5–7% for those 3.5–5.0 cm, and approach 0% for aneurysms less than 3.5 cm.5 The management options for an unruptured abdominal aortic aneurysm previously included conventional ‘open’
repair and watchful waiting (encompassing regular ultrasonic surveillance and optimisation of medical risk factors). Standard surgical repair, involving a large abdominal incision and cross-clamping of the aorta, is frequently complicated by the high likelihood of associated comorbidities and has an average mortality of approximately 2% increasing to 6% in higher risk patients.6 With an ageing population, the number of high risk cases also increases. Average blood loss is 2–3 units in 95% of cases with an average hospital stay of 6 days.5,6 In recent years, a new minimally invasive technique, endovascular aneurysm repair (EVAR), has been developed and incorporated into the management options for the elective repair of an infrarenal AAA as an alternative to conventional surgery.
2.
Endovascular aneurysm repair (EVAR)
EVAR was invented in the early 1990s by surgeons in the Ukraine and Argentina as a less invasive method of AAA
E-mail address: [email protected] 1743-9191/$ – see front matter ª 2008 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.ijsu.2008.02.001
international journal of surgery 6 (2008) 266–269
repair. Improvement of the devices and development of the technology have led EVAR to be used worldwide. Endovascular aneurysm repair involves the transfemoral or transiliac placement of an endograft within the aneurysm via two small incisions made in the patient’s groin. The aim being the complete exclusion of the aneurysm sac from the circulation. The endograft is anchored in place by self-expanding or balloonexpandable stents, which may support all or part of the graft. Endovascular grafts fall into three broad categories: (i) bifurcated or tubular unibody grafts (ii) modular multicomponent grafts (iii) aorto unilateral grafts with a contralateral iliac occluder which are followed by surgical femoro-femoral bypass7
- Dissection of the aortic neck may cause damage to the renal, adrenal, lumbar and gonadal veins - Aortic cross-clamping increases cardiac stress with increased cardiac afterload. It also leads to visceral and renal ischaemia (after suprarenal clamping), and lower limb ischaemia with the systemic complications of ischaemiareperfusion injury Two recent randomised trials12,13 have reported a twothirds reduction in the 30-day mortality rate with elective EVAR compared with conventional open surgery (1.6% and 1.2% for EVAR compared with 4.6% and 6% for open repair).
2.3. 2.1.
Anatomical suitability
The eligibility of a patient with an infrarenal AAA for endovascular repair relies on certain anatomical requirements for complete aneurysm exclusion. Aneurysms that rupture are associated with larger diameters than their intact counterparts. It has been suggested that larger aneurysms have more adverse morphological features which may increase the technical difficulty and therefore reduce the applicability of the endovascular technique. Several authors, however, have reported the applicability of EVAR in approximately 60% of AAA’s.8–10 Contrast-enhanced spiral CT has become the investigation of choice in the assessment of elective AAA for EVAR.11 Occasionally, angiography is also used. Generally speaking, the anatomical determinations which must be made in planning graft implantation are: - diameter and length of the infrarenal aorta and neck of the aorta - diameter and length of the iliac attachments (‘landing zones’) - tortuosity and size of the access vessels - critical vessel anatomy
Criteria of eligibility for EVAR -
2.2.
Neck length 15 mm Neck diameter < 30 mm Neck angulation < 60–80 Iliac diameter 7 mm
Advantages of EVAR
267
Complications of EVAR
EVAR is not without its complications and these differ substantially from those encountered with open repair. The majority of complications are related to the procedure itself. Early complications (<30 days) include: - wound complications: infection, haematomas, lymphoceles - arterial access complications: arterial perforation, rupture, dissection and plaque embolisation, pseudoaneurysm formation - renal ostia coverage - hypogastric artery embolisation complications: buttock claudication, gluteal myonecrosis and renal failure - endoleaks - endograft limb occlusion/thrombosis - systemic complications: despite EVAR resulting in fewer systemic complications than open surgical repair, these complications still represent the most frequent complication in the post-procedure period. The range of complications includes cardiac and pulmonary dysfunction, renal failure, embolic phenomena and spinal cord ischaemia Late complications: these are typically diagnosed on imaging studies for graft surveillance. The common routine is a CT scan at 1, 6 and 12 months post-procedure, and annually thereafter. Late complications include: -
Certain problems associated with conventional open repair of AAA, and thus contributing to morbidity and mortality, that are avoided by EVAR include the following:
-
- Open repair requires general anaesthetic - Laparotomy, third space fluid losses, ileus, postoperative ventilatory impairment, urinary retention, delayed mobility, prolonged hospitalisation
-
wound complications: lymphoceles and pseudoan-eurysms endoleaks endograft limb occlusion/thrombosis graft migration neck dilatation sac expansion endotension: defined as an increase in sac pressure without the presence of an endoleak graft infection aortoduodenal fistula implant-related complications: hook fractures, modular component separation and fabric erosion systemic complications: very few occur in the late period. The surveillance regimen of serial CT scans with intravenous contrast can, in certain patients, lead to contrastinduced nephropathy
268
2.4.
international journal of surgery 6 (2008) 266–269
Endoleaks
A problem unique to EVAR is endoleaks which describe ‘‘the inability to obtain or maintain a secure seal between the aortic wall and a transluminally implanted intra-aneurysmal graft’’.14 In essence, endoleaks are the presence of flow outside the lumen of the endograft but within the aneurysm sac. They increase the risk of aneurysm rupture and are the primary reason for such close surveillance following the procedure. The rate of endoleak following endovascular repair of AAA is approximately 14%.15 There are four types; Type I – anastomotic at the attachment sites; Type II – collateral back bleeding into the aneurysm sac; Type III – modular dissociation; Type IV – graft material porosity. Each type of endoleak can be noted during the procedure or surveillance period and all endoleaks may not be of equal significance. Both Type I (attachment site) and Type III (modular limb dislocation or graft fabric failure) are significant risk factors for late aneurysm rupture.16 In contrast, Type II endoleaks are generally considered as benign with only isolated cases of aneurysm expansion and rupture.17 Type IV endoleaks usually resolve spontaneously during the post-procedure period.
Classification of endoleaks I Attachment site leaks
- Proximal end of endograft - Distal end of endograft - Iliac occluder (plug) II Branch leaks (without attachment site connection)
- Simple or to-and-fro (from only one patent branch) - Complex or flow-through (with two or more patent branches) III Graft defect
- Junctional leak or modular disconnection - Fabric disruption (mid-graft hole) Minor (<2 mm, e.g. suture holes) Major (2 mm) IV Graft wall (fabric) porosity (<30 days after graft placement)
3.
Conclusion
Since Parodi undertook the first endograft repair of an AAA in 1990, there has been great excitement.18 The new treatment and technologies created much optimism and anticipation which must now be tempered by clinical experience and practical considerations. EVAR is currently constrained by both technical limitations and patient selection criteria and consequently, is not applicable to many patients with AAA. EVAR requires significant commitments from the participating physicians and the facilities in both time and logistical support. The promise of decreasing mortalities and shortened hospital stays are countered by the extremely high
cost of devices and the application of aneurysm repair to a higher risk patient population. Large delivery catheters exclude many women whose small iliac arteries will not accommodate such devices. EVAR is an exciting but demanding technology which holds great promise. The hope for the future is less costly, smaller profile devices with wider applicability, improved stability and fixation, and the elimination of endoleaks providing a durable repair comparable to a surgical graft. Continued research and development are needed in order to make EVAR an exclusively percutaneous procedure and attain these goals, thus improving patient care.
Conflicts of interest None declared.
references
1. Johansen K, Kohler TR, Nicholls SC, Zierler RE, Clowes AW, Kazmers A. Ruptured abdominal aortic aneurysms: the Harbour view experience. J Vasc Surg 1991;13:240–7. 2. Kniemeyer HW, Kessler T, Reber PU, Ris HB, Hakki H, Widmer MK. Treatment of ruptured abdominal aortic aneurysms: a permanent challenge or waste of resources? Prediction of outcome using multi-organ dysfunction score. Eur J Vasc Endovasc Surg 2000;19:190–6. 3. Noel AA, Gloviczki P, Cherry Jr KJ, Bower TC, Panneton JM, Mozes GI, et al. Ruptured abdominal aortic aneurysms: the excessive mortality rate of conventional repair. J Vasc Surg 2001;34:41–6. 4. Heller JA, Weinberg A, Arons R, Krishnasastry KV, Lyon RT, Deitch JS, et al. Two decades of aortic abdominal aneurysm repair: have we made any progress? J Vasc Surg 2000;32: 1091–100. 5. Wyffels P. Abdominal aortic aneurysms: natural history and surgical treatment. In: Dolmath B, Blum U, editors. Stent grafts: current clinical practice; 2000. p. 43–54. 6. Hollier LH, Reigel MM, Kazmier FJ, Pairolero PC, Cherry KJ, Hallett Jr JW. Conventional repair of abdominal aortic aneurysm in the high-risk patient: a plea for abandonment of non-resective treatment. J Vasc Surg 1986;3:712. 7. Veith F. History potential influence and facility requirements of transluminally placed endovascular grafts. In: Parodi JA, Veith F, Marin M, editors. Endovascular grafting techniques. Philadelphia: William and Wilkins; 1999. p. 1–5. 8. Armon MP, Yusuf SW, Latief K, Whitaker SC, Gregson RH, Wenham PW, et al. Anatomical suitability of abdominal aortic aneurysms for endovascular repair. Br J Surg 1997;84:178–80. 9. Woodburn KR, Chant H, Davies JN, Blanshard KS, Travis SJ. Suitability for endovascular aneurysm repair in an unselected population. Br J Surg 2001;88:77–81. 10. Bayle O, Branchereau A, Rosset E, Guillemot E, Beaurain P, Ferdani M, et al. Morphologic assessment of abdominal aortic aneurysms by spiral computed tomographic scanning. J Vasc Surg 1997;26:238–46. 11. Willmann JK, Lachat ML, von Smekal A, Turina MI, Pfammatter T. Spiral-CT angiography to assess feasibility of endovascular aneurysm repair in patients with ruptured aorto-iliac aneurysm. VASA 2001;30:271–6. 12. Greenhalgh RM, Brown LC, Kwong GP, Powell GT, Thompson SG. Comparison of endovascular aneurysm repair with open repair in patients with abdominal aortic aneurysm (EVAR Trial 1), 30 day operative mortality results: randomised control trial. Lancet 2004;364:843–8.
international journal of surgery 6 (2008) 266–269
13. Prinssen M, Verhoeven EL, Buth J, Cuypers PW, van Sambeek MR, Balm R, et al. A randomised trial comparing conventional and endovascular repair of abdominal aortic aneurysms. N Engl J Med 2004;351:1607–18. 14. White GH, Yu W, May J. Endoleak – a proposed new terminology to describe incomplete aneurysm exclusion by an endoluminal graft [letter]. J Endovasc Surg 1996;3:124–5. 15. Wain RA, Marin ML, Ohki T, Sanchez LA, Lyon RT, Rozenblit A, et al. Endoleaks as a complication of endovascular treatment of aortic aneurysms: classification, risk factors and outcome. J Vasc Surg 1998;27:69.
269
16. van Marrewijk C, Buth J, Harris PL, Norgren L, Nevelsteen A, Wyatt MG. Significance of endoleaks after endovascular repair of abdominal aortic aneurysms: the EUROSTAR experience. J Vasc Surg 2002;35:461–73. 17. Hinchliffe RJ, Singh-Ranger R, Davidson IR, Hopkinson BR. Rupture of an abdominal aortic aneurysm secondary to type II endoleak. Eur J Vasc Endovasc Surg 2001;22: 563–5. 18. Parodi JC, Palmaz JC, Barone HD. Transfemoral intraluminal graft implantation for abdominal aortic aneurysms. Ann Vasc Surg 1991;5:491–6.