Late open conversion after endovascular abdominal aortic aneurysm repair George Kouvelos, MD, PhD,a Andreas Koutsoumpelis, MD, MSc,a Andreas Lazaris, MD, PhD,b and Miltiadis Matsagkas, MD, PhD,a Ioannina and Athens, Greece Objective: This study determined the incidence, the surgical details, and the outcome of late open conversion after failed endovascular aneurysm repair (EVAR) for abdominal aortic aneurysm. Methods: A review of English-language medical literature from 1991 to 2014 was conducted using the PubMed and EMBASE databases to find all studies involving late conversion after EVAR for abdominal aortic aneurysm. The search identified 26 articles encompassing 641 patients (84% men; median age, 73.5 years). Results: Mean interval from the initial implantation was 38.5 6 10.7 months. The cumulative single-center open conversion rate was 3.7%. The indications for late open conversion included endoleak in 62.4%, infection in 9.5%, migration in 5.5%, and thrombosis in 6.7%. Operations were urgent in 22.5% of the patients. The 30-day mortality was 9.1%. Mortality rates were different between elective (3.2%) and nonelective patients (29.2%). Five aneurysm-related deaths (1.5%) and two graft infections (0.6%) occurred during a median follow-up of 26.4 months (range, 5-50.2 months). Conclusions: The number of patients with failed EVAR and without further options for endovascular salvage is growing. Endoleak remains the most important weakness of EVAR as the leading cause of late open conversion. Such procedures, although technically demanding, are associated with relatively low mortality rates when performed electively. Open repair still represents a valuable solution for many patients with failed EVAR. (J Vasc Surg 2015;61:1350-6.)
Endovascular abdominal aortic aneurysm (AAA) repair (EVAR) has gained widespread acceptance as the preferred method of treatment of suitable patients with infrarenal AAA, accounting for >70% of all AAA repairs in most large referral centers.1 The technique is associated with significantly lower short-term and midterm mortality and reduced hospital stay, but also with increased late reintervention rates compared with open surgical repair.2 Longterm results have been challenged by the presence of endoleaks, persistent aneurysm sac growth, and other aneurysm-related or graft-related complications. In some cases, conversion to open repair may be eventually needed despite reinterventions. Late open conversion after EVAR has been estimated initially near 2%. This incidence will possibly rise with the increasing numbers of patients treated endovascularly nowadays.3 New techniques, including custom-made fenestrated devices and chimney grafts, have been lately added in endovascular salvage of failed EVAR, with promising results.4,5 However, fenestration is usually restricted
From the Vascular Surgery Unit, Department of Surgery, University of Ioannina, Ioanninaa; and the Vascular Surgery Unit, 3rd Department of Surgery, University of Athens, Athens.b Author conflict of interest: none. Reprint requests: Miltiadis I. Matsagkas, MD, PhD, Department of Surgery, Vascular Surgery Unit, School of Medicine, University of Ioannina, Ioannina University Campus, S Niarchos Ave, 45110 Ioannina, Greece (e-mail: [email protected] or [email protected]). The editors and reviewers of this article have no relevant financial relationships to disclose per the JVS policy that requires reviewers to decline review of any manuscript for which they may have a conflict of interest. 0741-5214 Copyright Ó 2015 by the Society for Vascular Surgery. Published by Elsevier Inc. http://dx.doi.org/10.1016/j.jvs.2015.02.019
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to centers of expertise and is characterized by delays in availability due to complex manufacturing, whereas despite the initial technical success, chimney grafts lack mediumterm and long-term follow-up data. Moreover, clinicians have continued to push the limits of the technique to treat more anatomically difficult aneurysms, even in off-label conditions, challenging the durability of the method. The reports of late open conversion after EVAR have increased in frequency in recent years, revealing an increasing population without further options for endovascular salvage that should be thoroughly studied. We therefore conducted a systematic review of the literature and analyzed the reported cases of late open conversion after EVAR to determine the incidence, the surgical details, and the outcome of these patients.
METHODS Our Institutional Review Committee approved the study. Eligibility criteria. The objectives, the methodology of the systematic review and analysis, and the inclusion criteria for study enrollment were prespecified. Standard Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines6 were followed and documented in advance in a formal protocol. Studies considered for inclusion and full-text review fulfilled the following criteria: (1) reported open conversion after EVAR, (2) included at least five patients, and (3) provided outcome and perioperative data separately for late open conversion. Two reviewers (G.K., A.K.) assessed the eligibility of studies for inclusion in this review independently in an unblinded standardized manner. Disagreements between reviewers were arbitrated by discussion.
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Fig 1. Literature search strategy.
Search. An electronic search was conducted of the English-language medical literature from 1991 to July 2014 using the PubMed and EMBASE databases to find all studies relevant to open conversion after EVAR for AAA. Search terms included “open conversion,” or “surgical conversion” or “explantation” and “EVAR” and “abdominal aneurysm.” Related articles suggested by the PubMed search engine and reviews on this subject were searched for additional relevant articles. Further articles were also identified via examination of the references cited in the initially identified reports. When more than one publication on the same topic came from the same institution, only the most recent study was included in the analysis. The reviewers extracted the following from each study: publication year, country of origin, number of patients, time from implantation, AAA diameter initially and at conversion, cause of conversion, type of endograft, intraoperative variations, 30-day mortality, mean followup, and outcome during follow-up. Means of outcome parameters were weighted and data were pooled after significant outcome heterogeneity was excluded. Data analysis was performed using SPSS 20 software (IBM Corp, Armonk, NY). RESULTS The initial search identified 544 articles potentially suitable for inclusion in the review (Fig 1). After articles whose titles had no relevance to the area of concern of this review and subsequent publications on the same topic from the same institution were excluded, the full texts of 28 articles were retrieved and assessed for eligibility. The manual search of the reference list of the selected articles added
another two citations. Four articles were excluded because they did not provide data separately for the patients treated with open conversion.7-10 The final analysis included 26 articles.11-35 Characteristics of the studies included are summarized in Table I. One study was a prospective review from multiple centers, three studies were retrospective reviews from multiple centers, and 22 studies were retrospective reviews from a single center. None of the single-center reports were included in any of the multicenter studies. The studies were published between 2001 and 2014, and the study cohorts ranged from 5 to 100 patients. The population of this review comprised 641 patients (84% males) who were a median age of 73.5 years. Mean duration of the open conversion from the initial implantation was 38.5 6 10.7 months (Fig 2). Detailed data on reinterventions before conversion were available from 14 studies and included 219 procedures in 381 patients (57.5%). The open conversion rate for each center was clearly reported in 19 studies and averaged 3.7% (range, 0.9%-22.8%). Procedures were elective in 497 patients (77.5%) and were urgent in 144 (22.5%). Indications. The indications for late open conversion are shown in Fig 3. The most common included endoleak in 400 patients (62.4%), infection in 61 (9.5%), migration in 35 (5.5%), and thrombosis in 43 (6.7%). Forty-eight patients (7.5%) underwent emergency operations due to aneurysm rupture. The endoleak group included 168 type I (42%), 107 type II (26.8%), 36 type III (9%), 2 type IV (0.5%), and 24 type V (6%). Thirty-eight patients (9.5%) presented with more than one different concomitant endoleaks, whereas in 25 (6.2%) the type of
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Table I. Characteristics of included studies Sex (male)
Time from implantation, months
Reported center Reintervention incidence pre
Hospital LOS, days
30-day mortality, %
FU, months
NR 19.8 (7-42) 9.9 (5-19) 20 6 21
5.9 20 18 11
NR NR 22 (3-56) 29 6 28
First author
Year
Pt
Age, years
Schlensak11 Lyden12 Lipsitz13 Terramani14
2001 2002 2003 2003
17 5 11 9
69 72 (63-86) 7668.4 75 6 7
NR 5 11 8
26.7 32 (18-44) 30 (10-64) 24 (2-48)
17/150 5/110 9/386 NR
NR 1 4 NR
Verhoeven15 Kong16 Verzini17
2004 2005 2006
9 16 29
NR 75 (62-83) NR
NR 13 25
44 (24-57) 40 33 (7-85)
NR 16/594 NR
5 NR 5
11 (10-11) 11.2 6 12.6 6 (4-7)
2006 Brewster18 Tiesenhausen19 2006 20 2007 Jimenez
15 26 12
NR 69.7 NR
NR 22 NR
31 36.7 26.4 6 25
15/873 26/114 NR
NR 16 NR
NR 12.8 9.6 6 6.4
Millon21
2009
20
NR
NR
41 (2-117)
20/1588
7
NR
Nabi22 Pitoulias23 Gambardella24 Brinster25 Phade3
2009 2009 2010 2011 2011
12 81 6 6.2 39 70.2 6 6.3 12 75 21 75 (59-88) 16 73
9 32 10 16 15
44.7 (7-80) 39 6 5.1 54.5 (12-92) 33.4 NR
NR 39/617 10/285 12/1273 5/531
8 NR NR 14 7
8.4 6 8 12.6 6 4.8 6 (4-7) 10 (4-39) 18
Mertens26 Forbes27 Chaar28
2011 2011 2012
5 6 44
NR 71 (58-83) 74 6 8
NR 3 34
54 (32-65) 5/143 15.6 (1.7-61.3) 6/892 45 (2-190) 38/1682
NR NR 22
NR 7 (6-73) 13 6 11
Marone29
2012
54
73 6 5.6
47
63 (3-102)
NR
30
6 (5-27)
Ferrero30 Arya32
2013 2013
20 75.4 6 6.7 39 71.9 (46-88)
19 25
49.7 41.7
NR 26/270
NR 22
16 (1-50) 13.9
20 5
Turney33 Klonaris31 Botsios34 Wu35
2013 100 75 (50-93) 2014 18 73.9 (55-91) 2014 9 71 (59-79) 2014 77 73.1 (54-86)
91 17 9 62
(1-144) (2-120) (14-60) (4-83)
49/1881 8/442 8/411 77/1729
NR 7 NR 71
15 (1-56) 7.8 (3-13) 22 (14-52) 9.6
17 5.6 0 5.2
41 36 34 28
0 6.25 0 20 11.5 0 15 8.3 8.8 0 0 12 0 0 18
1.9
Outcome NR NR
All OK 2 deaths aneurysm unrelated NR All OK NR NR 27 (1-60) 2 deaths (stroke, AMI), 1 infection limb req in situ new bypass NR NR NR NR 33.8 6 30.2 2 unrelated deaths 67-52, 1 death renal failure 3 months 37.4 (5-72) 2 conversion-related deaths, 1 graft infection at 5 years 14.2 6 8.5 All pts OK NR NR 5 1 pt died of AMI 50.2 (18-92) All OK 64 12 pts (86%) were alive at FU NR NR NR NR 20 6 24 1 death from aneurysm growth, 1 intervention with relining 19 (5-63) 1 death AEF 4 years after, 3 cancers, 4 cardiac deaths 28 6 30.7 All pts OK 23 6 deaths probably nonaneurysm related NR NR 25.7 (2-60) All pts OK 29 (4-61) All pts OK NR NR
AEF, Aortoenteric fistula; AMI, acute myocardial infarction; LOS, length of stay; FU, follow-up, NR, not reported; Pt, patient.
the endoleak was not defined. Of the 61 patients with graft infection as an indication for open conversion, 31 (50.8%) were treated urgently. Grafts and operative technique. The type of the stent grafts converted is reported in Table II. The grafts were Excluder (W. L. Gore & Associates, Flagstaff, Ariz) in 15.3%, followed by AneuRx (Medtronic, Santa Rosa, Calif) in 15.1%, Zenith (Cook, Bloomington, Ind) in 14.2%, and Vanguard (Boston Scientific Ltd, St Albans, United Kingdom) in 12.8%. Fixation was infrarenal in 376 endografts (58.7%), suprarenal in 181 (28.2%), and insufficient fixation data were provided for 84 patients (13.1%). Detailed data for the type of approach was evident in 587 patients. A transperitoneal approach was used in 477 patients (81.4%). A midline incision was performed in 465 of these patients (97.5%), and a bilateral subcostal incision was used in 12 (2.5%). A retroperitoneal approach was used in 109 patients (18.6%), and a thoracoabdominal approach was used in only one patient. Detailed data for proximal cross-clamping were available in 581 patients and was infrarenal in 250 patients (43%), suprarenal in
152 (26.2%), and supraceliac in 162 (27.9%). An aortic balloon was used for proximal aortic occlusion in two patients (0.3%), and no aortic clamping was performed in 15 patients (2.6%). Graft removal detailed data were available for 566 patients. The graft was completely removed in 372 patients (65.7%), whereas the graft was partially explanted in 167 (29.5%) and the conventional surgical graft was sutured in the remaining part of the endovascular graft. The endograft was totally preserved in 27 patients (4.8%). Nineteen of these patients underwent selective ligation of the culprit arteries causing a type II endoleak, comprising the lumbar artery in 13, the inferior mesenteric artery in five, and the middle sacral artery in one. External banding of the aortic neck was performed in the remaining eight patients. Outcome. Thirty-day mortality was 9.1%. Mortality rates were different between elective and nonelective cases. The 30-day mortality was 3.2% in patients treated electively and was 29.2% in patients treated urgently. Overall, there were 11 deaths in the infection group during the 30-day postoperative period. Of these 11 patients who died,
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Table II. Types of different endografts converted Endograft Ancure Vanguard Stentor Talent AneuRx Endurant Excluder Zenith Anaconda Endologix Misc Not reported
Fig 2. Graph shows the time interval from the initial implantation to open conversion.
Fig 3. Causes of late open conversion after endovascular aneurysm repair (EVAR). AEF, Aortoenteric fistula, Endo combin, combination of different endoleaks; Endo undef, undefined endoleak.
three of 30 (10%) were treated electively and eight of 31 (25.8%) were urgent cases. Median hospital length of stay was 11.1 days. Long-term outcome data were available in 332 patients (59.8%). During a median follow-up of 26.4 months (range, 5-50.2 months), there were five aneurysm-related deaths (1.5%) and two graft infections (0.6%). DISCUSSION The need for late open conversion of failed endografts has increased in recent years in most centers, probably as a result of the growing number of EVAR patients.33 This review found the cumulative single-center rate of late open conversion was nearly 4% (range 0.9%-22.8%). Moulakakis et al,36 by reviewing studies until 2009, reported a late conversion rate of 1.9%, whereas the rate of conversion to open repair in the Endovascular Aneurysm Repair Versus Open
No. (%) 49 82 9 75 97 5 98 91 18 18 33 66
(7.6) (12.8) (1.4) (11.7) (15.1) (0.7) (15.3) (14.2) (2.9) (2.9) (5.1) (10.3)
Anaconda, Sulzer Vascutech, Bad Soden, Germany; Ancure, Guidant, Indianapolis, Ind; AneuRx, Medtronic, Santa Rosa, Calif; Endurant, Medtronic, Minneapolis, Minn; Endologix, Endologix, Inc, Irvine, Calif; Excluder, W. L. Gore & Associates, Flagstaff, Ariz; Stentor, MinTec, La Ciotat, France; Talent, Medtronic, Minneapolis, Minn; Vanguard, Boston Scientific Ltd, St. Albans, United Kingdom; Zenith, Cook, Bloomington, Ind.
Repair in Patients With Abdominal Aortic Aneurysm (EVAR) 1 trial37 was 2.6% at 3 years of follow-up. The increased incidence found in this review may most likely reflect the constant rising number of conversions reported in the literature, because half of the studies included have been published the last 4 years. Owing to reporting bias, the incidence may be even higher because many single cases of open conversion may have not been published. EVAR offers an undisputed operative benefit in operative mortality over open repair, although this early gain has not been translated into a long-term survival advantage.38 As reported in EVAR-1 trial, the early benefit has been completely lost in the long-term, even leading to a slightly higher aneurysm-related mortality at 4 years after EVAR.37 Moreover, higher reintervention rates in the long-term have also been reported in most of the randomized controlled trials and may account for this difference in mortality rates.1,2,37 In this review, we report a mean time from the initial endovascular implantation to open conversion of nearly 3 years. Although data are insufficient, 55% of the converted patients had undergone an endovascular intervention that failed. Which factors may affect the continuing occurrence of graft-related complications and reinterventions in the long-term need to be clearly defined. Meticulous preoperative planning, understanding device limitations, and more efficacious minimally invasive reinterventions may improve the long-term outcome. Conversion was elective in 77.5% of the cases in this review. Endoleaks (62.4%) and graft infection (9.5%) were the two most common indications. Turney et al,33 in the largest reported series to date, found that patients who required late explantation most commonly presented with type Ia and III endoleaks. These types of endoleak show a significant risk for early rupture and should be promptly treated.39 Furthermore, the need to treat high-risk patients with hostile aortic neck anatomies has extended the use of
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the stent grafts even in off-label conditions, and therefore, an increase in the incidence of type I endoleak may be expected.40 Aneurysmal degeneration of the proximal landing zone was clearly evaluated in none of the studies included in this review. However, this aortic degeneration and the failure of the endograft device have probably accounted for many of the cases of late open conversion, highlighting the fact that surveillance with detailed imaging should not be abandoned. Although it is generally accepted that type I and III endoleaks should be aggressively treated, the indication for endoleak type II management remains controversial.33 This review found that type II endoleaks accounted for nearly 17% of open conversions. Jones et al41 reported that patients with a persistent type II endoleak showed significantly higher rates of conversion to open repair. However, Sidloff et al42 in a systematic review published recently, studied 21,744 patients from 32 nonrandomized studies and found a remarkably low rate of post-EVAR rupture secondary to an isolated type II endoleak. Reporting bias may have accounted for these disagreements, because many conversions due to endoleak type II might have been under-reported. It would have been of interest to define the exact relation of type II endoleak with the aneurysm sac enlargement and secondary intervention failure as well as the proportion of the total number of type II endoleaks that may rupture, although these data were insufficient in most of the reports included in this review. According to this study, type II endoleak does not seem to be the benign condition that it was generally believed to be, and some of these patients may eventually need open conversion, yielding the necessity for close and constant surveillance. Late conversion after EVAR can be accomplished with complete explantation or partial preservation of the endograft. In this review, complete endograft removal was achieved in 65.7% of the patients included. In many cases, however, well-incorporated endografts might be difficult to explant, or there was no need to explant and partial removal could often be achieved.29,33 Explantation maneuvers, especially in endografts designed with active suprarenal fixation, may raise the risk of severe aortic wall injury.43 In the absence of a proximal endoleak, a partial stent graft removal strategy may lead to a lower risk of serious complications and better operative outcome.31 Of course, the risk for delayed complications from the remnant endograft remains, and therefore, these patients should be continuously monitored. Complete endograft extraction is necessary when late conversion is performed for an infected endograft to minimize persistent infection. These cases are usually technically challenging, and hence, supraceliac clamping and complex (extra-anatomic, renal, or mesenteric, or a combination) reconstructions are often needed, and damage to the aortic wall cannot be ruled out.32 In all other cases, the preservation of the suprarenal portion of the endograft, especially that with an active fixation, and the incorporation of it in the proximal anastomosis, might be the best and simpler option to choose.
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Open conversion of an aortic stent graft is often technically demanding. Control of the aorta above the proximal fixation site is of utmost importance in safe removal of the endograft. In this review, proximal control to enable graft explantation was suprarenal or supraceliac in nearly half of the cases. In grafts with infrarenal fixation, temporary suprarenal clamping is usually sufficient as long as an adequate length between the renal ostia and the superior mesenteric artery exists.32,43 Grafts with suprarenal fixation, however, require additional dissection and supraceliac clamping to achieve proximal aortic control and to avoid injury to the native aorta during the removal of the bare stents of the graft. Furthermore, the periaortic inflammation sometimes noted at the proximal aortic neck, especially when barbs or hooks are involved, makes dissection above the renal arteries tedious, and in these cases, proximal control using an aortic balloon might be helpful.43 Late conversion after EVAR has been generally hampered by high mortality rates. Harris et al44 reported a 24% mortality rate in the European Collaborators on Stent-Graft Techniques for Abdominal Aortic Aneurysm Repair (EUROSTAR) registry. Thirty-day mortality in this review was 9.1%. A remarkable difference was noted in patients treated electively (3.2%) compared with those treated urgently (29.2%). Aneurysm rupture or infection have been considered absolute indications for urgent operation and have been accompanied by relatively high mortality rates, even in the absence of a previous endograft.44 Prompt recognition of other indications for open conversion, such as sac enlargement, material failure, or persistent endoleak, may be proven life-saving for the patient. Fenestrated or branched endovascular options may constitute a therapeutic option in these patients, although their use is limited to some centers of expertise around the world and not always accessible to most AAA patients with failed EVAR.45 In many patients with failed EVAR, elective open conversion seems be an efficient therapeutic approach with low mortality rates. The difference in outcome after elective and urgent open conversion highlights the importance of constant and meticulous surveillance and challenges the decision making about the best time to proceed to open conversion. Most of the endografts included in this review were from previous generations. Al-Jubouri et al46 examined the frequency and reasons for reinterventions in nearly 600 patients undergoing EVAR and reported a significant reduction in all reinterventions in third-generation endografts compared with older grafts. However, whether conversion rates are lower in newer endografts has not been proven, because none of the studies included in the present review directly compared endografts of different generations. Furthermore, some endografts, such as Zenith and Excluder, have been changed and improved over time without the name of the system being changed, and these differences in types of the same endograft have not been considered in any study. Undoubtedly, newer devices providing suprarenal fixation and more secure proximal and distal attachment are better.
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Still, despite the technologic advancement and the increasing experience of endovascular surgeons, some patients will definitely need open conversion. Unfortunately, the decline in open aortic repairs performed in most centers worldwide may have important implications for future attending experience.47 There is a doubt whether vascular surgeons will retain the skills to confront such demanding cases in the future. This review has several limitations. Most of the studies were retrospective, and some had small numbers of patients. Selection bias, because clinicians usually report patients with the best outcomes, as well as the wide range of the year of publication, should also be acknowledged. There was marked variability in duration of follow-up among studies, with the longest being 5.2 years. This heterogeneity and lack of detailed data make it problematic to perform any further statistical analysis. CONCLUSIONS The number of patients with failed EVAR and without further options for endovascular salvage seems to grow. Open conversion has been reported more often in recent years, revealing a patient population that needs to be studied in detail. Endoleak, as the leading cause of late open conversion, remains the most important weakness of EVAR. Such procedures, although technically demanding, are associated with relatively low mortality rates when performed electively. At the moment, open repair still represents a valuable solution for many patients with failed EVAR. AUTHOR CONTRIBUTIONS Conception and design: GK, MM Analysis and interpretation: GK Data collection: GK, AK Writing the article: GK Critical revision of the article: AL, MM Final approval of the article: MM Statistical analysis: GK Obtained funding: Not applicable Overall responsibility: MM REFERENCES 1. Schwarze ML, Shen Y, Hemmerich J, Dale W. Age-related trends in utilization and outcome of open and endovascular repair for abdominal aortic aneurysm in the United States, 2001-2006. J Vasc Surg 2009;50: 722-9. 2. United Kingdom EVAR Trial Investigators, Greenhalgh RM, Brown LC, Powell JT, Thompson SG, Epstein D, Sculpher MJ. Endovascular versus open repair of abdominal aortic aneurysm. N Engl J Med 2010;362:1863-71. 3. Phade SV, Keldahl ML, Morasch MD, Rodriguez HE, Pearce WH, Kibbe MR, et al. Late abdominal aortic endograft explants: indications and outcomes. Surgery 2011;150:788-95. 4. Katsargyris A, Oikonomou K, Spinelli D, Houthoofd S, Verhoeven EL. Fenestrated and branched stent-grafting after previous open or endovascular aortic surgery. J Cardiovasc Surg (Torino) 2014;55:95-103. 5. Donas KP, Pecoraro F, Torsello G, Lachat M, Austermann M, Mayer D, et al. Use of covered chimney stents for pararenal aortic
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pathologies is safe and feasible with excellent patency and low incidence of endoleaks. J Vasc Surg 2012;55:659-65. Moher D, Liberati A, Tetzlaff J, Altman DG; PRISMA Group. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. Int J Surg 2010;8:336-41. van Marrewijk CJ, Fransen G, Laheij RJ, Harris PL, Buth J. Is a type II endoleak after EVAR a harbinger of risk? Causes and outcome of open conversion and aneurysm rupture during follow-up. Eur J Vasc Endovasc Surg 2004;27:128-37. Coppi G, Silingardi R, Tasselli S, Gennai S, Saitta G, Veraldi GF. Endovascular treatment of abdominal aortic aneurysms with the Powerlink Endograft System: influence of placement on the bifurcation and use of a proximal extension on early and late outcomes. J Vasc Surg 2008;48:795-801. Lifeline Registry of EVAR Publications Committee. Lifeline registry of endovascular aneurysm repair: long term primary outcome measures. J Vasc Surg 2005;42:1-10. Pratesi C, Piffaretti G, Pratesi G, Castelli P; Italian Excluder Registry (ITER) Investigators. ITalian Excluder Registry and results of Gore Excluder endograft for the treatment of elective infrarenal abdominal aortic aneurysms. J Vasc Surg 2014;59:52-7. Schlensak C, Doenst T, Hauer M, Bitu-Moreno J, Uhrmeister P, Spillner G, et al. Serious complications that require surgical interventions after endoluminal stent graft placement for the treatment of infrarenal aortic aneurysms. J Vasc Surg 2001;34:198-203. Lyden SP, McNamara JM, Sternbach Y, Illig KA, Waldman DL, Green RM. Technical considerations for late removal of aortic endografts. J Vasc Surg 2002;36:674-8. Lipsitz EC, Ohki T, Veith FJ, Suggs WD, Wain RA, Rhee SJ, et al. Delayed open conversion following endovascular aortoiliac aneurysm repair: partial (or complete) endograft preservation as a useful adjunct. J Vasc Surg 2003;38:1191-8. Terramani TT, Chaikof EL, Rayan SS, Lin PH, Najibi S, Bush RL, et al. Secondary conversion due to failed endovascular abdominal aortic aneurysm repair. J Vasc Surg 2003;38:473-7. Verhoeven EL, Tielliu IF, Prins TR, Zeebregts CJ, van Andringa de Kempenaer MG, Cinà CS, et al. Frequency and outcome of reinterventions after endovascular repair for abdominal aortic aneurysm: a prospective cohort study. Eur J Vasc Endovasc Surg 2004;28:357-64. Kong LS, MacMillan D, Kasirajan K, Milner R, Dodson TF, Salam AA, et al. Secondary conversion of the Gore Excluder to operative abdominal aortic aneurysm repair. J Vasc Surg 2005;42:631-8. Verzini F, Cao P, De Rango P, Parlani G, Xanthopoulos D, Iacono G, et al. Conversion to open repair after endografting for abdominal aortic aneurysm: causes, incidence and results. Eur J Vasc Surg 2006;31: 136-42. Brewster DC, Jones JE, Chung TK, Lamuraglia GM, Kwolek CJ, Watkins MT, et al. Long-term outcomes after endovascular abdominal aortic aneurysm repair: the first decade. Ann Surg 2006;244:426-38. Tiesenhausen K, Hessinger M, Konstantiniuk P, Tomka M, Baumann A, Thalhammer M, et al. Surgical conversion of abdominal aortic stent-graftsdoutcome and technical considerations. Eur J Vasc Endovasc Surg 2006;31:36-41. Jimenez JC, Moore WS, Quinones-Baldrich WJ. Acute and chronic open conversion after endovascular aortic aneurysm repair: a 14-year review. J Vasc Surg 2007;46:642-7. Millon A, Deelchand A, Feugier P, Chevalier JM, Favre JP; University Association for Research in Vascular Surgery (AURC). Conversion to open repair after endovascular aneurysm repair: causes and results. A French multicentric study. Eur J Vasc Endovasc Surg 2009;38:429-34. Nabi D, Murphy EH, Pak J, Zarins CK. Open surgical repair after failed endovascular aneurysm repair: is endograft removal necessary? J Vasc Surg 2009;50:714-21. Pitoulias GA, Schulte S, Donas KP, Horsch S. Secondary endovascular and conversion procedures for failed endovascular abdominal aortic aneurysm repair: can we still be optimistic? Vascular 2009;17:15-22. Gambardella I, Blair PH, McKinley A, Makar R, Collins A, Ellis PK, et al. Successful delayed secondary open conversion after endovascular repair using partial explantation technique: a single-center experience. Ann Vasc Surg 2010;24:646-54.
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25. Brinster CJ, Fairman RM, Woo EY, Wang GJ, Carpenter JP, Jackson BM. Late open conversion and explantation of abdominal aortic stent grafts. J Vasc Surg 2011;54:42-6. 26. Mertens J, Houthoofd S, Daenens K, Fourneau I, Maleux G, Lerut P, et al. Long-term results after endovascular abdominal aortic aneurysm repair using the Cook Zenith endograft. J Vasc Surg 2011;54:48-57. 27. Forbes TL, Harrington DM, Harris JR, DeRose G. Late conversion of endovascular to open repair of abdominal aortic aneurysms. Can J Surg 2012;55:254-8. 28. Chaar CI, Eid R, Park T, Rhee RY, Abu-Hamad G, Tzeng E, et al. Delayed open conversions after endovascular abdominal aortic aneurysm repair. J Vasc Surg 2012;55:1562-9. 29. Marone EM, Mascia D, Coppi G, Tshomba Y, Bertoglio L, Kahlberg A, et al. Delayed open conversion after endovascular abdominal aortic aneurysm: device-specific surgical approach. Eur J Vasc Endovasc Surg 2013;45:457-64. 30. Ferrero E, Ferri M, Viazzo A, Pecchio A, Berardi G, Piazza S, et al. Open conversion after endovascular aortic aneurysm repair: a singlecenter experience. Ann Vasc Surg 2013;27:856-64. 31. Klonaris C, Lioudaki S, Katsargyris A, Psathas E, Kouvelos G, Doulaptsis M, et al. Late open conversion after failed endovascular aortic aneurysm repair. J Vasc Surg 2014;59:291-7. 32. Arya S, Coleman DM, Knepper J, Henke PK, Upchurch GR, Rectenwald JE, et al. Outcomes after late explantation of aortic endografts depend on indication for explantation. Ann Vasc Surg 2013;27:865-73. 33. Turney EJ, Steenberge SP, Lyden SP, Eagleton MJ, Srivastava SD, Sarac TP, et al. Late graft explants in endovascular aneurysm repair. J Vasc Surg 2014;59:886-93. 34. Botsios S, Bausback Y, Piorkowski M, Werner M, Branzan D, Sceinert D, et al. Late open conversion after endovascular aneurysm repair. Interact Cardiovasc Thorac Surg 2014;19:622-6. 35. Wu Z, Xu L, Qu L, Raithel D. Seventeen years’ experience of late open surgical conversion after failed endovascular abdominal aortic aneurysm repair with 13 variant devices. Cardiovasc Intervent Radiol 2015;38: 53-9. 36. Moulakakis KG, Dalainas I, Mylonas S, Giannakopoulos TG, Avgerinos ED, Liapis CD. Conversion to open repair after endografting for abdominal aortic aneurysm: a review of causes, incidence, results, and surgical techniques of reconstruction. J Endovasc Ther 2010;17:694-702. 37. EVAR trial participants. Endovascular aneurysm repair versus open repair in patients with abdominal aortic aneurysm (EVAR trial 1): randomised controlled trial. Lancet 2005;365:2179-86.
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38. Brown LC, Powell JT, Thompson SG, Epstein DM, Sculpher MJ, Greenhalgh RM. The UK EndoVascular Aneurysm Repair (EVAR) trials: randomised trials of EVAR versus standard therapy. Health Technol Assess 2012;16:1-218. 39. Bernhard VM, Mitchell RS, Matsumura JS, Brewster DC, Decker M, Lamparello P, et al. Ruptured abdominal aortic aneurysm after endovascular repair. J Vasc Surg 2002;35:1155-62. 40. Georgiadis GS, Trellopoulos G, Antoniou GA, Gallis K, Nikolopoulos ES, Kapoulas KC, et al. Early results of the Endurant endograft system in patients with friendly and hostile infrarenal abdominal aortic aneurysm anatomy. J Vasc Surg 2011;54:616-27. 41. Jones JE, Atkins MD, Brewster DC, Chung TK, Kwolek CJ, LaMuraglia GM, et al. Persistent type 2 endoleak after endovascular repair of abdominal aortic aneurysm is associated with adverse late outcomes. J Vasc Surg 2007;46:1-8. 42. Sidloff DA, Stather PW, Choke E, Bown MJ, Sayers RD. Type II endoleak after endovascular aneurysm repair. Br J Surg 2013;100: 1262-70. 43. Matsagkas M, Kouvelos GN, Peroulis M. Safe and fast proximal aortic control using an aortic balloon through direct graft puncture for the explantation of an abdominal endograft with suprarenal fixation. Interact Cardiovasc Thorac Surg 2014;18:519-21. 44. Harris PL, Vallabhaneni SR, Desgranges P, Becquemin JP, van Marrewijk C, Laheij RJ. Incidence and risk factors of late rupture, conversion, and death after endovascular repair of infrarenal aortic aneurysms: the EUROSTAR experience. European Collaborators on Stent/graft techniques for aortic aneurysm repair. J Vasc Surg 2000;32: 739-49. 45. Katsargyris A, Yazar O, Oikonomou K, Bekkema F, Tielliu I, Verhoeven EL. Fenestrated stent-grafts for salvage of prior endovascular abdominal aortic aneurysm repair. Eur J Vasc Endovasc Surg 2013;46:49-56. 46. Al-Jubouri M, Comerota AJ, Thakur S, Aziz F, Wanjiku S, Paolini D, et al. Reintervention after EVAR and open surgical repair of AAA: a 15year experience. Ann Surg 2013;258:652-7. 47. Sachs T, Schermerhorn M, Pomposelli F, Cotterill P, O’Malley J, Landon B. Resident and fellow experiences after the introduction of endovascular aneurysm repair for abdominal aortic aneurysm. J Vasc Surg 2011;54:881-8.
Submitted Aug 24, 2014; accepted Feb 9, 2015.
Endovascular abdominal aortic aneurysm (AAA) repair (EVAR) has gained widespread acceptance as the preferred method of treatment of suitable patients with infrarenal AAA, accounting for >70% of all AAA repairs in most large referral centers.1 The technique is associated with significantly lower short-term and midterm mortality and reduced hospital stay, but also with increased late reintervention rates compared with open surgical repair.2 Longterm results have been challenged by the presence of endoleaks, persistent aneurysm sac growth, and other aneurysm-related or graft-related complications. In some cases, conversion to open repair may be eventually needed despite reinterventions. Late open conversion after EVAR has been estimated initially near 2%. This incidence will possibly rise with the increasing numbers of patients treated endovascularly nowadays.3 New techniques, including custom-made fenestrated devices and chimney grafts, have been lately added in endovascular salvage of failed EVAR, with promising results.4,5 However, fenestration is usually restricted
From the Vascular Surgery Unit, Department of Surgery, University of Ioannina, Ioanninaa; and the Vascular Surgery Unit, 3rd Department of Surgery, University of Athens, Athens.b Author conflict of interest: none. Reprint requests: Miltiadis I. Matsagkas, MD, PhD, Department of Surgery, Vascular Surgery Unit, School of Medicine, University of Ioannina, Ioannina University Campus, S Niarchos Ave, 45110 Ioannina, Greece (e-mail: [email protected] or [email protected]). The editors and reviewers of this article have no relevant financial relationships to disclose per the JVS policy that requires reviewers to decline review of any manuscript for which they may have a conflict of interest. 0741-5214 Copyright Ó 2015 by the Society for Vascular Surgery. Published by Elsevier Inc. http://dx.doi.org/10.1016/j.jvs.2015.02.019
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to centers of expertise and is characterized by delays in availability due to complex manufacturing, whereas despite the initial technical success, chimney grafts lack mediumterm and long-term follow-up data. Moreover, clinicians have continued to push the limits of the technique to treat more anatomically difficult aneurysms, even in off-label conditions, challenging the durability of the method. The reports of late open conversion after EVAR have increased in frequency in recent years, revealing an increasing population without further options for endovascular salvage that should be thoroughly studied. We therefore conducted a systematic review of the literature and analyzed the reported cases of late open conversion after EVAR to determine the incidence, the surgical details, and the outcome of these patients.
METHODS Our Institutional Review Committee approved the study. Eligibility criteria. The objectives, the methodology of the systematic review and analysis, and the inclusion criteria for study enrollment were prespecified. Standard Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines6 were followed and documented in advance in a formal protocol. Studies considered for inclusion and full-text review fulfilled the following criteria: (1) reported open conversion after EVAR, (2) included at least five patients, and (3) provided outcome and perioperative data separately for late open conversion. Two reviewers (G.K., A.K.) assessed the eligibility of studies for inclusion in this review independently in an unblinded standardized manner. Disagreements between reviewers were arbitrated by discussion.
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Fig 1. Literature search strategy.
Search. An electronic search was conducted of the English-language medical literature from 1991 to July 2014 using the PubMed and EMBASE databases to find all studies relevant to open conversion after EVAR for AAA. Search terms included “open conversion,” or “surgical conversion” or “explantation” and “EVAR” and “abdominal aneurysm.” Related articles suggested by the PubMed search engine and reviews on this subject were searched for additional relevant articles. Further articles were also identified via examination of the references cited in the initially identified reports. When more than one publication on the same topic came from the same institution, only the most recent study was included in the analysis. The reviewers extracted the following from each study: publication year, country of origin, number of patients, time from implantation, AAA diameter initially and at conversion, cause of conversion, type of endograft, intraoperative variations, 30-day mortality, mean followup, and outcome during follow-up. Means of outcome parameters were weighted and data were pooled after significant outcome heterogeneity was excluded. Data analysis was performed using SPSS 20 software (IBM Corp, Armonk, NY). RESULTS The initial search identified 544 articles potentially suitable for inclusion in the review (Fig 1). After articles whose titles had no relevance to the area of concern of this review and subsequent publications on the same topic from the same institution were excluded, the full texts of 28 articles were retrieved and assessed for eligibility. The manual search of the reference list of the selected articles added
another two citations. Four articles were excluded because they did not provide data separately for the patients treated with open conversion.7-10 The final analysis included 26 articles.11-35 Characteristics of the studies included are summarized in Table I. One study was a prospective review from multiple centers, three studies were retrospective reviews from multiple centers, and 22 studies were retrospective reviews from a single center. None of the single-center reports were included in any of the multicenter studies. The studies were published between 2001 and 2014, and the study cohorts ranged from 5 to 100 patients. The population of this review comprised 641 patients (84% males) who were a median age of 73.5 years. Mean duration of the open conversion from the initial implantation was 38.5 6 10.7 months (Fig 2). Detailed data on reinterventions before conversion were available from 14 studies and included 219 procedures in 381 patients (57.5%). The open conversion rate for each center was clearly reported in 19 studies and averaged 3.7% (range, 0.9%-22.8%). Procedures were elective in 497 patients (77.5%) and were urgent in 144 (22.5%). Indications. The indications for late open conversion are shown in Fig 3. The most common included endoleak in 400 patients (62.4%), infection in 61 (9.5%), migration in 35 (5.5%), and thrombosis in 43 (6.7%). Forty-eight patients (7.5%) underwent emergency operations due to aneurysm rupture. The endoleak group included 168 type I (42%), 107 type II (26.8%), 36 type III (9%), 2 type IV (0.5%), and 24 type V (6%). Thirty-eight patients (9.5%) presented with more than one different concomitant endoleaks, whereas in 25 (6.2%) the type of
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Table I. Characteristics of included studies Sex (male)
Time from implantation, months
Reported center Reintervention incidence pre
Hospital LOS, days
30-day mortality, %
FU, months
NR 19.8 (7-42) 9.9 (5-19) 20 6 21
5.9 20 18 11
NR NR 22 (3-56) 29 6 28
First author
Year
Pt
Age, years
Schlensak11 Lyden12 Lipsitz13 Terramani14
2001 2002 2003 2003
17 5 11 9
69 72 (63-86) 7668.4 75 6 7
NR 5 11 8
26.7 32 (18-44) 30 (10-64) 24 (2-48)
17/150 5/110 9/386 NR
NR 1 4 NR
Verhoeven15 Kong16 Verzini17
2004 2005 2006
9 16 29
NR 75 (62-83) NR
NR 13 25
44 (24-57) 40 33 (7-85)
NR 16/594 NR
5 NR 5
11 (10-11) 11.2 6 12.6 6 (4-7)
2006 Brewster18 Tiesenhausen19 2006 20 2007 Jimenez
15 26 12
NR 69.7 NR
NR 22 NR
31 36.7 26.4 6 25
15/873 26/114 NR
NR 16 NR
NR 12.8 9.6 6 6.4
Millon21
2009
20
NR
NR
41 (2-117)
20/1588
7
NR
Nabi22 Pitoulias23 Gambardella24 Brinster25 Phade3
2009 2009 2010 2011 2011
12 81 6 6.2 39 70.2 6 6.3 12 75 21 75 (59-88) 16 73
9 32 10 16 15
44.7 (7-80) 39 6 5.1 54.5 (12-92) 33.4 NR
NR 39/617 10/285 12/1273 5/531
8 NR NR 14 7
8.4 6 8 12.6 6 4.8 6 (4-7) 10 (4-39) 18
Mertens26 Forbes27 Chaar28
2011 2011 2012
5 6 44
NR 71 (58-83) 74 6 8
NR 3 34
54 (32-65) 5/143 15.6 (1.7-61.3) 6/892 45 (2-190) 38/1682
NR NR 22
NR 7 (6-73) 13 6 11
Marone29
2012
54
73 6 5.6
47
63 (3-102)
NR
30
6 (5-27)
Ferrero30 Arya32
2013 2013
20 75.4 6 6.7 39 71.9 (46-88)
19 25
49.7 41.7
NR 26/270
NR 22
16 (1-50) 13.9
20 5
Turney33 Klonaris31 Botsios34 Wu35
2013 100 75 (50-93) 2014 18 73.9 (55-91) 2014 9 71 (59-79) 2014 77 73.1 (54-86)
91 17 9 62
(1-144) (2-120) (14-60) (4-83)
49/1881 8/442 8/411 77/1729
NR 7 NR 71
15 (1-56) 7.8 (3-13) 22 (14-52) 9.6
17 5.6 0 5.2
41 36 34 28
0 6.25 0 20 11.5 0 15 8.3 8.8 0 0 12 0 0 18
1.9
Outcome NR NR
All OK 2 deaths aneurysm unrelated NR All OK NR NR 27 (1-60) 2 deaths (stroke, AMI), 1 infection limb req in situ new bypass NR NR NR NR 33.8 6 30.2 2 unrelated deaths 67-52, 1 death renal failure 3 months 37.4 (5-72) 2 conversion-related deaths, 1 graft infection at 5 years 14.2 6 8.5 All pts OK NR NR 5 1 pt died of AMI 50.2 (18-92) All OK 64 12 pts (86%) were alive at FU NR NR NR NR 20 6 24 1 death from aneurysm growth, 1 intervention with relining 19 (5-63) 1 death AEF 4 years after, 3 cancers, 4 cardiac deaths 28 6 30.7 All pts OK 23 6 deaths probably nonaneurysm related NR NR 25.7 (2-60) All pts OK 29 (4-61) All pts OK NR NR
AEF, Aortoenteric fistula; AMI, acute myocardial infarction; LOS, length of stay; FU, follow-up, NR, not reported; Pt, patient.
the endoleak was not defined. Of the 61 patients with graft infection as an indication for open conversion, 31 (50.8%) were treated urgently. Grafts and operative technique. The type of the stent grafts converted is reported in Table II. The grafts were Excluder (W. L. Gore & Associates, Flagstaff, Ariz) in 15.3%, followed by AneuRx (Medtronic, Santa Rosa, Calif) in 15.1%, Zenith (Cook, Bloomington, Ind) in 14.2%, and Vanguard (Boston Scientific Ltd, St Albans, United Kingdom) in 12.8%. Fixation was infrarenal in 376 endografts (58.7%), suprarenal in 181 (28.2%), and insufficient fixation data were provided for 84 patients (13.1%). Detailed data for the type of approach was evident in 587 patients. A transperitoneal approach was used in 477 patients (81.4%). A midline incision was performed in 465 of these patients (97.5%), and a bilateral subcostal incision was used in 12 (2.5%). A retroperitoneal approach was used in 109 patients (18.6%), and a thoracoabdominal approach was used in only one patient. Detailed data for proximal cross-clamping were available in 581 patients and was infrarenal in 250 patients (43%), suprarenal in
152 (26.2%), and supraceliac in 162 (27.9%). An aortic balloon was used for proximal aortic occlusion in two patients (0.3%), and no aortic clamping was performed in 15 patients (2.6%). Graft removal detailed data were available for 566 patients. The graft was completely removed in 372 patients (65.7%), whereas the graft was partially explanted in 167 (29.5%) and the conventional surgical graft was sutured in the remaining part of the endovascular graft. The endograft was totally preserved in 27 patients (4.8%). Nineteen of these patients underwent selective ligation of the culprit arteries causing a type II endoleak, comprising the lumbar artery in 13, the inferior mesenteric artery in five, and the middle sacral artery in one. External banding of the aortic neck was performed in the remaining eight patients. Outcome. Thirty-day mortality was 9.1%. Mortality rates were different between elective and nonelective cases. The 30-day mortality was 3.2% in patients treated electively and was 29.2% in patients treated urgently. Overall, there were 11 deaths in the infection group during the 30-day postoperative period. Of these 11 patients who died,
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Table II. Types of different endografts converted Endograft Ancure Vanguard Stentor Talent AneuRx Endurant Excluder Zenith Anaconda Endologix Misc Not reported
Fig 2. Graph shows the time interval from the initial implantation to open conversion.
Fig 3. Causes of late open conversion after endovascular aneurysm repair (EVAR). AEF, Aortoenteric fistula, Endo combin, combination of different endoleaks; Endo undef, undefined endoleak.
three of 30 (10%) were treated electively and eight of 31 (25.8%) were urgent cases. Median hospital length of stay was 11.1 days. Long-term outcome data were available in 332 patients (59.8%). During a median follow-up of 26.4 months (range, 5-50.2 months), there were five aneurysm-related deaths (1.5%) and two graft infections (0.6%). DISCUSSION The need for late open conversion of failed endografts has increased in recent years in most centers, probably as a result of the growing number of EVAR patients.33 This review found the cumulative single-center rate of late open conversion was nearly 4% (range 0.9%-22.8%). Moulakakis et al,36 by reviewing studies until 2009, reported a late conversion rate of 1.9%, whereas the rate of conversion to open repair in the Endovascular Aneurysm Repair Versus Open
No. (%) 49 82 9 75 97 5 98 91 18 18 33 66
(7.6) (12.8) (1.4) (11.7) (15.1) (0.7) (15.3) (14.2) (2.9) (2.9) (5.1) (10.3)
Anaconda, Sulzer Vascutech, Bad Soden, Germany; Ancure, Guidant, Indianapolis, Ind; AneuRx, Medtronic, Santa Rosa, Calif; Endurant, Medtronic, Minneapolis, Minn; Endologix, Endologix, Inc, Irvine, Calif; Excluder, W. L. Gore & Associates, Flagstaff, Ariz; Stentor, MinTec, La Ciotat, France; Talent, Medtronic, Minneapolis, Minn; Vanguard, Boston Scientific Ltd, St. Albans, United Kingdom; Zenith, Cook, Bloomington, Ind.
Repair in Patients With Abdominal Aortic Aneurysm (EVAR) 1 trial37 was 2.6% at 3 years of follow-up. The increased incidence found in this review may most likely reflect the constant rising number of conversions reported in the literature, because half of the studies included have been published the last 4 years. Owing to reporting bias, the incidence may be even higher because many single cases of open conversion may have not been published. EVAR offers an undisputed operative benefit in operative mortality over open repair, although this early gain has not been translated into a long-term survival advantage.38 As reported in EVAR-1 trial, the early benefit has been completely lost in the long-term, even leading to a slightly higher aneurysm-related mortality at 4 years after EVAR.37 Moreover, higher reintervention rates in the long-term have also been reported in most of the randomized controlled trials and may account for this difference in mortality rates.1,2,37 In this review, we report a mean time from the initial endovascular implantation to open conversion of nearly 3 years. Although data are insufficient, 55% of the converted patients had undergone an endovascular intervention that failed. Which factors may affect the continuing occurrence of graft-related complications and reinterventions in the long-term need to be clearly defined. Meticulous preoperative planning, understanding device limitations, and more efficacious minimally invasive reinterventions may improve the long-term outcome. Conversion was elective in 77.5% of the cases in this review. Endoleaks (62.4%) and graft infection (9.5%) were the two most common indications. Turney et al,33 in the largest reported series to date, found that patients who required late explantation most commonly presented with type Ia and III endoleaks. These types of endoleak show a significant risk for early rupture and should be promptly treated.39 Furthermore, the need to treat high-risk patients with hostile aortic neck anatomies has extended the use of
1354 Kouvelos et al
the stent grafts even in off-label conditions, and therefore, an increase in the incidence of type I endoleak may be expected.40 Aneurysmal degeneration of the proximal landing zone was clearly evaluated in none of the studies included in this review. However, this aortic degeneration and the failure of the endograft device have probably accounted for many of the cases of late open conversion, highlighting the fact that surveillance with detailed imaging should not be abandoned. Although it is generally accepted that type I and III endoleaks should be aggressively treated, the indication for endoleak type II management remains controversial.33 This review found that type II endoleaks accounted for nearly 17% of open conversions. Jones et al41 reported that patients with a persistent type II endoleak showed significantly higher rates of conversion to open repair. However, Sidloff et al42 in a systematic review published recently, studied 21,744 patients from 32 nonrandomized studies and found a remarkably low rate of post-EVAR rupture secondary to an isolated type II endoleak. Reporting bias may have accounted for these disagreements, because many conversions due to endoleak type II might have been under-reported. It would have been of interest to define the exact relation of type II endoleak with the aneurysm sac enlargement and secondary intervention failure as well as the proportion of the total number of type II endoleaks that may rupture, although these data were insufficient in most of the reports included in this review. According to this study, type II endoleak does not seem to be the benign condition that it was generally believed to be, and some of these patients may eventually need open conversion, yielding the necessity for close and constant surveillance. Late conversion after EVAR can be accomplished with complete explantation or partial preservation of the endograft. In this review, complete endograft removal was achieved in 65.7% of the patients included. In many cases, however, well-incorporated endografts might be difficult to explant, or there was no need to explant and partial removal could often be achieved.29,33 Explantation maneuvers, especially in endografts designed with active suprarenal fixation, may raise the risk of severe aortic wall injury.43 In the absence of a proximal endoleak, a partial stent graft removal strategy may lead to a lower risk of serious complications and better operative outcome.31 Of course, the risk for delayed complications from the remnant endograft remains, and therefore, these patients should be continuously monitored. Complete endograft extraction is necessary when late conversion is performed for an infected endograft to minimize persistent infection. These cases are usually technically challenging, and hence, supraceliac clamping and complex (extra-anatomic, renal, or mesenteric, or a combination) reconstructions are often needed, and damage to the aortic wall cannot be ruled out.32 In all other cases, the preservation of the suprarenal portion of the endograft, especially that with an active fixation, and the incorporation of it in the proximal anastomosis, might be the best and simpler option to choose.
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Open conversion of an aortic stent graft is often technically demanding. Control of the aorta above the proximal fixation site is of utmost importance in safe removal of the endograft. In this review, proximal control to enable graft explantation was suprarenal or supraceliac in nearly half of the cases. In grafts with infrarenal fixation, temporary suprarenal clamping is usually sufficient as long as an adequate length between the renal ostia and the superior mesenteric artery exists.32,43 Grafts with suprarenal fixation, however, require additional dissection and supraceliac clamping to achieve proximal aortic control and to avoid injury to the native aorta during the removal of the bare stents of the graft. Furthermore, the periaortic inflammation sometimes noted at the proximal aortic neck, especially when barbs or hooks are involved, makes dissection above the renal arteries tedious, and in these cases, proximal control using an aortic balloon might be helpful.43 Late conversion after EVAR has been generally hampered by high mortality rates. Harris et al44 reported a 24% mortality rate in the European Collaborators on Stent-Graft Techniques for Abdominal Aortic Aneurysm Repair (EUROSTAR) registry. Thirty-day mortality in this review was 9.1%. A remarkable difference was noted in patients treated electively (3.2%) compared with those treated urgently (29.2%). Aneurysm rupture or infection have been considered absolute indications for urgent operation and have been accompanied by relatively high mortality rates, even in the absence of a previous endograft.44 Prompt recognition of other indications for open conversion, such as sac enlargement, material failure, or persistent endoleak, may be proven life-saving for the patient. Fenestrated or branched endovascular options may constitute a therapeutic option in these patients, although their use is limited to some centers of expertise around the world and not always accessible to most AAA patients with failed EVAR.45 In many patients with failed EVAR, elective open conversion seems be an efficient therapeutic approach with low mortality rates. The difference in outcome after elective and urgent open conversion highlights the importance of constant and meticulous surveillance and challenges the decision making about the best time to proceed to open conversion. Most of the endografts included in this review were from previous generations. Al-Jubouri et al46 examined the frequency and reasons for reinterventions in nearly 600 patients undergoing EVAR and reported a significant reduction in all reinterventions in third-generation endografts compared with older grafts. However, whether conversion rates are lower in newer endografts has not been proven, because none of the studies included in the present review directly compared endografts of different generations. Furthermore, some endografts, such as Zenith and Excluder, have been changed and improved over time without the name of the system being changed, and these differences in types of the same endograft have not been considered in any study. Undoubtedly, newer devices providing suprarenal fixation and more secure proximal and distal attachment are better.
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Still, despite the technologic advancement and the increasing experience of endovascular surgeons, some patients will definitely need open conversion. Unfortunately, the decline in open aortic repairs performed in most centers worldwide may have important implications for future attending experience.47 There is a doubt whether vascular surgeons will retain the skills to confront such demanding cases in the future. This review has several limitations. Most of the studies were retrospective, and some had small numbers of patients. Selection bias, because clinicians usually report patients with the best outcomes, as well as the wide range of the year of publication, should also be acknowledged. There was marked variability in duration of follow-up among studies, with the longest being 5.2 years. This heterogeneity and lack of detailed data make it problematic to perform any further statistical analysis. CONCLUSIONS The number of patients with failed EVAR and without further options for endovascular salvage seems to grow. Open conversion has been reported more often in recent years, revealing a patient population that needs to be studied in detail. Endoleak, as the leading cause of late open conversion, remains the most important weakness of EVAR. Such procedures, although technically demanding, are associated with relatively low mortality rates when performed electively. At the moment, open repair still represents a valuable solution for many patients with failed EVAR. AUTHOR CONTRIBUTIONS Conception and design: GK, MM Analysis and interpretation: GK Data collection: GK, AK Writing the article: GK Critical revision of the article: AL, MM Final approval of the article: MM Statistical analysis: GK Obtained funding: Not applicable Overall responsibility: MM REFERENCES 1. Schwarze ML, Shen Y, Hemmerich J, Dale W. Age-related trends in utilization and outcome of open and endovascular repair for abdominal aortic aneurysm in the United States, 2001-2006. J Vasc Surg 2009;50: 722-9. 2. United Kingdom EVAR Trial Investigators, Greenhalgh RM, Brown LC, Powell JT, Thompson SG, Epstein D, Sculpher MJ. Endovascular versus open repair of abdominal aortic aneurysm. N Engl J Med 2010;362:1863-71. 3. Phade SV, Keldahl ML, Morasch MD, Rodriguez HE, Pearce WH, Kibbe MR, et al. Late abdominal aortic endograft explants: indications and outcomes. Surgery 2011;150:788-95. 4. Katsargyris A, Oikonomou K, Spinelli D, Houthoofd S, Verhoeven EL. Fenestrated and branched stent-grafting after previous open or endovascular aortic surgery. J Cardiovasc Surg (Torino) 2014;55:95-103. 5. Donas KP, Pecoraro F, Torsello G, Lachat M, Austermann M, Mayer D, et al. Use of covered chimney stents for pararenal aortic
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Submitted Aug 24, 2014; accepted Feb 9, 2015.
