Endovascular Aneurysm Sealing: Early and Midterm Results From the EVAS FORWARD Global Registry

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1 664365JETXXX / Journal of Endovascular TherapyThompson et al research-article2016 Clinical Investigation Endovascular Aneurysm Sealing: Early and Midterm Results From the EVAS FORWARD Global Registry Journal of Endovascular Therapy 2016, Vol. 23(5) The Author(s) 2016 Reprints and permissions: sagepub.com/journalspermissions.nav DOI: / Matt M. Thompson, MD, FRCS 1, Jan M. Heyligers, MD, PhD 2, Paul D. Hayes, MD, FRCS 3, Michel M. P. J. Reijnen, MD, PhD 4, Dittmar Böckler, MD, PhD 5, Hubert Schelzig, MD 6, Jean-Paul P. M. de Vries, MD, PhD 7, Dainis Krievins, MD, PhD 8, and Andrew Holden, MBChB, FRANZCR, EBIR 9 for the EVAS FORWARD Global Registry Investigators Abstract Purpose: To report the early and 12-month results of a global registry of patients treated with endovascular aneurysm sealing (EVAS) for abdominal aortic aneurysms (AAAs). Methods: The EVAS FORWARD Global Registry was a postmarket, multicenter, open-label, single-arm registry that enrolled 277 patients (mean age 75 years; 228 men) treated with the Nellix EVAS system for nonruptured AAAs at 18 sites over a 1-year period. The cohort had challenging aortic anatomy, with 17% having a proximal aortic neck length <10 mm, 8% a neck angulation >60, and 20% an iliac diameter >25 mm. Baseline and follow-up computed tomography images were assessed by an independent core laboratory, and major adverse events were reviewed by an independent safety committee. Results: Three patients died within 30 days of the procedure (none device-related). There were 13 endoleaks recorded in this time frame: 8 type Ia, 1 type Ib, and 5 type II. Root cause analysis demonstrated that the majority of type Ia endoleaks were due to technical error (low device placement and underfilling of the endobags). Between 30 days and 1 year, there were 4 new type Ia endoleaks; all were treated. There was also 1 type III endoleak between a Nellix device and a distal extension limb. At 1 year, the persistent endoleak rate was 0.7% (1 type Ia and 1 type II). The Kaplan-Meier estimates of freedom from types I and II endoleak at 12-month follow-up were 96% and 98%, respectively. The estimate of freedom from open conversion (n=7) was 98% at 12 months and the rate of freedom from any reintervention was 92%. The need for secondary intervention was associated with aortic morphology; for patients meeting the requirements of the instructions for use (IFU), the freedom from reintervention at 12 months was 98% compared with 86% when the implant was outside the IFU (p=0.009). At 1 year, the estimates of freedom from aortic-related and all-cause mortality were 98% and 95%, respectively. Conclusion: The EVAS FORWARD Global Registry documents the 12-month outcome of EVAS in an unselected group of patients with challenging aortic morphology. The results at present appear acceptable with regard to perioperative outcomes and complications. The type II endoleak rate is low. The place of EVAS in the armamentarium of techniques to treat AAAs will be defined by durability data in the longer term. Keywords abdominal aortic aneurysm, endoleak, endovascular aneurysm sealing, mortality, reintervention, sac-anchoring stent-graft Introduction Endovascular aneurysm sealing (EVAS) is a new concept in the treatment of abdominal aortic aneurysms (AAA), which offers some potential advantages over traditional endovascular aneurysm repair (EVAR). The Nellix system (Endologix, Irvine, CA, USA) for EVAS consists of 2 polytetrafluoroethylene-covered cobalt chromium stents, both with an integrated endobag. One Nellix stent is placed through each femoral artery and deployed adjacent to the lowermost renal artery and proximal to the internal iliac artery by inflation of the Nellix balloons. Having created a flow lumen through the stents, the aneurysm is sealed by instillation of an aqueous polyethylene glycol based polymer into the endobags. Planning for EVAS involves calculation of the appropriate stent length and the volume of the aortic flow lumen (for polymer volume estimation) between the renal artery and iliac bifurcation. 1 Theoretically, EVAS may address some of the issues that limit the utility of EVAR, namely, constrained patient applicability and continued sac perfusion that necessitates surveillance and reintervention and negatively influences

2 686 Journal of Endovascular Therapy 23(5) long-term durability. The polymer-filled endobags provide anatomical fixation within not only the landing zones but throughout the entire aneurysm sac while extending the seal zones in the proximal aorta and iliac arteries. These features may allow more challenging aortic anatomies to be treated, and early morphological studies suggest that Nellix may be able to treat a higher proportion of aneurysms within the instructions for use (IFU) than many commercially available endografts. 2 The ability of the endobags to fill the aneurysm sac may reduce type II endoleaks, which may impact surveillance strategies and the need for subsequent aortic reintervention. The necessity for aortic reintervention remains a persistent problem after EVAR, especially in patients with adverse aortic anatomy. 3 Although EVAS has a number of potential advantages over conventional EVAR, the introduction of any new technology must be accompanied by extensive and rigorous data collection to define the performance of the graft in comparison to existing standard technology. 4 The present study presents the early and midterm clinical results of a global EVAS registry. Methods Study Design The EVAS FORWARD Global Registry was a postmarket, multicenter, open-label, single-arm, real-world registry assessing outcomes in patients who underwent EVAS with the Nellix system. The study was approved by the local ethics committee in 30 international study sites where the device was commercially available. Each site was required to perform a minimum of 4 training cases prior to entering patients into the registry. Enrollment was consecutive at each site. Morphologic eligibility for treatment with the Nellix system was determined by the treating clinician according to high-resolution contrast-enhanced computed tomography (CT). All patients treated with the Nellix system were eligible for the study, irrespective of whether their aortic anatomy conformed to the Nellix IFU. Written informed consent was obtained from all patients according to local regulations. Baseline and follow-up CT images were assessed by an independent core laboratory (Cleveland Clinic, Cleveland, OH, USA), and major adverse events were reviewed by an independent safety committee. EVAS Procedure The operative procedure was performed according to institutional protocol. The implantation procedure for the Nellix system has been previously described. 1,5 Pre-, peri-, and postoperative data were collected prospectively according to defined parameters. Patients were followed to hospital discharge as per institutional standard of care and will be followed through to 5 years. Standard of care follow-up assessments typically included clinical assessment and imaging follow-up with high-resolution contrast-enhanced CT scans and/or duplex ultrasound. Patient Population In a 1-year period (October 30, 2013 to September 29, 2014), 300 patients were enrolled in 18 participating centers. One patient did not undergo EVAS after enrollment (angiography demonstrated inadequate infrarenal neck length, so the procedure was terminated; 6-week follow-up imaging revealed no change in AAA diameter). For this analysis, 22 additional patients who underwent EVAS for ruptured AAA (n=5), a failing bifurcated endograft (n=7), or isolated iliac aneurysm (n=10) were excluded, leaving 277 patients (mean age 75 years; 228 men) in the study group. The baseline characteristics and aortic morphologic characteristics of the patient cohort are tabulated in Tables 1 and 2, respectively. Overall 200 patients were treated within the IFU with a neck length 10 mm and/or a β angle 60 ; 39 had a neck length between 5 and 10 mm and/or a β angle between 61 and 90, while 38 had a neck length <5 mm and/or β angle >90. In the last cohort, there were 15 patients with juxtarenal or pararenal aortic aneurysms who had concomitant parallel grafts to the renal arteries. Overall, 44 (17%) of 263 patients with available data had a proximal 1 St George s Vascular Institute, St George s NHS Trust Hospital, London, UK 2 Department of Vascular Surgery, St Elisabeth Hospital, Tilburg, the Netherlands 3 Department of Vascular Surgery, Addenbrookes Hospital, Cambridge, UK 4 Department of Surgery, Rijnstate Hospital, Arnhem, the Netherlands 5 Department of Vascular and Endovascular Surgery, Ruprecht-Karls University Heidelberg, Germany 6 Department of Vascular and Endovascular Surgery, University of Düsseldorf, Germany 7 Department of Vascular Surgery, St Antonius Hospital, Nieuwegein, the Netherlands 8 Department of Vascular Surgery, Stradins University Hospital, Riga, Latvia 9 Department of Interventional Radiology, Auckland Hospital, Auckland, New Zealand Corresponding Author: Matt M. Thompson, MD, FRCS, St George s Vascular Institute, 4th Floor St James Wing, St George s University Hospitals NHS Foundation Trust, London SW17 0QT, UK. profmattthompson@gmail.com

3 Thompson et al 687 Table 1. Characteristics of the 277 Study Patients. a Demographics Age, y 75.1±7.2 >80 y 71 (26) Men 228 (82) Caucasian 274 (99) BMI, kg/m 2 27±5 egfr, b ml/min/1.73 m 2 69±22 Risk factors and comorbidities Angina 53 (19) Arrhythmia 48 (17) Coronary artery disease 120 (43) Congestive heart failure 20 (7) Family history of AAA 21 (8) Hyperlipidemia 117 (42) Hypercholesterolemia 142 (51) Hypertension 208 (75) Chronic obstructive pulmonary disease 75 (27) Diabetes mellitus 47 (17) Renal insufficiency 53 (19) History of smoking 145 (52) Stroke/TIA 21 (8) / 23 (8) Cancer 55 (20) Liver disease 7 (3) Paraplegia 1 Coagulopathy or uncontrolled bleeding 4 (1) disorder Heart valve disease 22 (8) Myocardial infarction 70 (25) Peripheral vascular disease 79 (29) Peripheral artery disease 59 (21) Thoracic aortic aneurysm 16 (6) Aortic valve repair or replacement 12 (4) History of abdominal surgery 63 (23) History of CABG 42 (15) Pacemaker or implantable cardioverterdefibrillator 11 (4) Percutaneous coronary intervention 54 (19) ASA class (n=274) I 6 (2) II 93 (34) III 140 (51) IV 35 (13) Abbreviations: AAA, abdominal aortic aneurysm; ASA, American Society of Anesthesiologists; BMI, body mass index; CABG, coronary artery bypass graft; egfr, estimated glomerular filtration rate; TIA, transient ischemic attack. a Continuous data are presented as the means ± standard deviation; categorical data are given as the counts (percentage). b Calculated with the MDRD (Modification of Diet in Renal Disease) equation: 175 (serum creatinine 1.154) (age 0.203) (0.742 if female) (1.212 if African American). aortic neck length <10 mm, 21 (8%) of 268 patients had a β angle >60, and 55 (20%) of 271 patients had an iliac artery diameter >25 mm. Table 2. Aortic Morphology. a,b Maximum AAA sac diameter, mm 59.5 (55.3, 65.2) <55 62/271 (23) /271 (77) Nonaneurysmal neck length, mm 23.6 (13.7, 37.4) <5 15/263 (6) 5 to <10 29/263 (11) 10 to <15 30/263 (11) /263 (72) Aortic neck angulation (β angle), deg 31 (17, 44) <60 247/268 (92) 61 to <90 18/268 (7) 90 3/268 (1) AAA lumen diameter, mm 40.8 (34.4, 47.0) Maximum left CIA diameter, mm 17.2 (14.8, 21.1) <15 71/271 (26) 15 to <25 168/239 (62) 25 to <35 29/239 (11) 35 3/271 (1) Maximum right CIA diameter, mm 17.8 (14.6, 22.1) <15 72/271 (27) 15 to <25 159/271 (59) 25 to <35 27/271 (10) 35 13/271 (5) Neck diameter at distal renal artery, mm 25.3 (22.9, 28.5) <20 13/269 (5) 20 to <25 111/269 (41) 25 to <30 100/269 (37) 30 45/269 (17) AAA volume, ml 171 (137, 231) <100 22/263 (8) 100 to < /263 (53) 200 to <300 77/263 (29) /263 (9) Blood lumen volume, ml 80 (59.5, 113) <50 38/260 (15) 50 to < /260 (53) 100 to <150 56/260 (22) /260 (11) Sac thrombus volume, ml 85 (54, 131) Abbreviations: AAA, abdominal aortic aneurysm; CIA, common iliac artery. a Continuous data are presented as the median (interquartile range); categorical data are given as the counts (percentage). b Results range beyond the manufacturer s indications for use, which include an infrarenal aortic neck length 10 mm, proximal aortic neck angulation 60, aortic neck diameter of 18 to 32 mm, aneurysm blood lumen diameter 6 cm, CIA lumen diameter of 9 to 35 mm, and access artery diameter 6 mm. Statistical Analysis Continuous data are presented as the means ± standard deviation or median [interquartile range (IQR)] as appropriate; categorical data are given as the counts (percentage). Kaplan-Meier estimates were utilized for survival and

4 688 Journal of Endovascular Therapy 23(5) Table 3. Major Adverse Events. a Event time-to-event analyses; groups were compared with the log-rank test. Freedom from reintervention was stratified by IFU status. The threshold of statistical significance was p<0.05. All statistical analyses were performed with SAS software (version 9.4; SAS Institute Inc, Cary, NC, USA). Results All 277 patients had a Nellix system implanted during procedures lasting a median 98 minutes (IQR 80, 121), with fluoroscopy time of 11 minutes (IQR 9, 16). The median contrast use was 110 ml (IQR 87, 150). Median intensive care unit stay was 0 days and in hospital stay was 4 days (IQR 3, 6). Three patients died within 30 days after EVAS, 2 from pneumonia and 1 from a gastrointestinal hemorrhage (not device-related). There were 2 patients with a myocardial infarction, 2 with respiratory failure, 1 with a stroke (single renal artery chimney), and 2 patients with blood loss >1000 ml. Major adverse events are listed in Table 3. Endoleak 30 Days (n=277) Days (n=272) All-cause death 3 (1.1) 11 (4.0) AAA-related mortality 3 (1.1) 1 (0.4) b Renal failure 0 2 (0.7) Myocardial infarction 2 (0.7) 1 (0.4) Bowel ischemia 0 0 Respiratory failure 2 (0.7) 2 (0.7) Stroke 1 (0.4) 3 (1.1) Blood loss >1000 ml 2 (0.7) NA 1 MAE 8 (2.9) 16 (5.9) Abbreviations: AAA, abdominal aortic aneurysm; MAE, major adverse event; NA, not applicable. a Data are given as the counts (percentage). b Death due to an aortoenteric fistula on day 148. Within 30 days after EVAS (0- to 90-day imaging window), there were 13 endoleaks recorded; 8 type Ia, 1 type Ib, and 5 type II. Root cause analysis of the type Ia endoleaks suggested that the majority were due to technical aspects of the procedure: implantation of the device caudal to the optimum sealing zone or insufficient polymer filling of the endobags. One type Ia endoleak resolved spontaneously, and 4 were treated by transcatheter coil embolization and/or liquid embolic agents. 6,7 All of the type II endoleaks were small volume (between 0.1 and 0.3 ml), and 4 resolved spontaneously. The single persisting type II endoleak remained unchanged at latest follow-up, with no sac expansion or associated clinical sequelae. The type Ib endoleak was treated by distal extension. Beyond 30 days there remained 3 type Ia endoleaks and 1 type II. Between 30 days and 1 year, there were 4 new type Ia endoleaks, all of which were treated with embolotherapy. One late type III endoleak occurred in a patient with a concomitant iliac aneurysm at the junction of the Nellix limb and another manufacturer s covered extension; an additional covered stent was implanted. At 1 year, the persistent total endoleak rate was 0.7% (1 type Ia and 1 type II). The Kaplan-Meier estimates for freedom from all endoleaks and from type Ia endoleak at 12 months (Figure 1A) were 94.5% and 96.3%, respectively. Aortic Rupture, Intraprocedural Aortic Injury, and Reinterventions One patient in the registry had an intraprocedural aortic injury that manifested as a retroperitoneal hematoma and anemia postoperatively. This was most likely caused by endobag-mediated damage to the aortic wall. No intervention was required according to the implanting physician. The procedure was successfully completed, no endoleak was present at the final angiogram, and both renal arteries were patent. There were 2 patients who had an iliac artery injury during passage of the endograft; both were treated with covered stents. Overall there were 5 limb occlusions in the 277 patients, 3 (1.1%) within 30 days and 2 (0.7%) on late follow-up; all were successfully treated endovascularly (thrombolysis, thrombectomy, and/or relining) with the exception of an iliofemoral bypass performed on day 47 for a late occlusion. Seven patients underwent removal of the Nellix device at open conversion, 2 within the perioperative period and 5 late. Of the 2 early conversions, one was ill-defined (the endograft was described as having a kinked appearance in an asymptomatic patient). The reason for the other early conversion was due to a device malfunction. During the Nellix implant procedure, the operator was unable to retrieve the lock wire and to withdraw the implant delivery system. The patient was converted to open repair, and the Nellix implant was successfully explanted. Subsequent to this incident, sites were instructed to inspect the lock wire under sterile conditions prior to use, and modifications to the lock wire/nosecone attachment mechanism were made to prevent further lock wire retraction issues. Of the 5 late conversions, 2 were due to infection of the prosthesis (one from an aortoduodenal fistula), 2 were due to type I endoleaks (one ruptured), and one was due to a presumed retroperitoneal hematoma without endoleak. There were 3 aortic ruptures, 1 early due to a type Ib endoleak treated with a distal extension and 2 late due to untreated type Ia endoleak resulting in conversion. The Kaplan-Meier estimate of freedom from open conversion was 97.8% at 12 months.

5 Thompson et al 689 Figure 1. Freedom from (A) type Ia and all endoleaks; (B) reintervention for endoleak, limb occlusion, and all reinterventions; (C) reintervention stratified by use within or outside the instructions for use (IFU); and (D) all-cause mortality and aneurysmrelated mortality. Numbers at risk are given for each graph. The estimated freedom from any reintervention was 92.3% (Figure 1B), which represents the treatment of 5 limb occlusions, 8 type I endoleaks, 1 type III endoleak, and the 7 conversions. The need for secondary intervention was associated with aortic morphology; for patients meeting the requirements of the IFU, the freedom from reintervention at 12 months was 98% as compared with 86% when the implant was outside the IFU (p=0.009; Figure 1C). Aneurysm-Related and All-Cause Mortality At 1 year the rates for freedom from aneurysm-related and all-cause mortality were 98.2% and 94.8%, respectively (Figure 1D). The aneurysm-related mortality comprised 4 patients, the 3 perioperative deaths described previously and 1 patient who died from an aortoenteric fistula at day 148 post-evas. Discussion The results presented define the outcomes of a patient cohort treated using EVAS after commercialization of the Nellix system. The patients did not undergo screening by a core laboratory before enrollment and represent a realworld cohort. In terms of aortic morphology, the EVAS FORWARD Global registry embodies a more challenging patient cohort compared to patients entered into EVAR registries. In the EVAS FORWARD registry, 17% of patients

6 690 Journal of Endovascular Therapy 23(5) had an aortic neck length <10 mm compared to 2% and 1.5%, respectively, in the ENGAGE 8 and GREAT 9 registries. Similarly, 20% of patients in the EVAS FORWARD registry had an iliac diameter >25 mm in comparison to 0.6% in the ENGAGE registry. One significant finding of the EVAS FORWARD registry is the low total endoleak rate. The mechanism of EVAS, with polymer-filled endobags sealing the aneurysm sac, should potentially result in a low rate of type II endoleak. This potential appears to have been fulfilled in the present study, with a 0.7% persistent endoleak rate at 12 months and a 98% 1-year freedom from type II endoleak, substantially lower compared with EVAR. The type II endoleak rate after EVAR varies with endograft and reporting standards but appears to occur in at least 10% of patients after EVAR. 10 There has been considerable debate in recent years regarding the prognostic significance of type II endoleaks, and the subject remains controversial. 11 Nevertheless, there are suggestions of adverse long-term outcomes in some patients with type II endoleaks, 12 and any technique that reduces their prevalence might have an impact on both long-term patient outcome and the need for close postoperative surveillance. Clearly, longer-term data are required to define the effect of a low type II endoleak rate on clinical practice. In the present study there were 8 type I endoleaks within 90 days of the index procedure. While this incidence would be higher than many contemporary studies, it is difficult to define how many would be attributable to the learning curve associated with a new technique in aortic repair. Root cause analysis of the patients with early type I endoleaks suggested that technical errors (low deployment of the stents and underfilling of the endobags) during the procedure were responsible for the majority of the cases. It will be important to understand how increased global and institutional experience affects the early endoleak rate as more data become available. The treatment of type I endoleak post-evas is crucial because the established bailout techniques that have evolved for EVAR (proximal balloon molding, proximal cuffs, fenestrated cuffs) are not applicable to the Nellix stent configuration comprised of 2 individual 10-mm stents applied to the aortic neck. In the EVAS FORWARD registry, 4 early and 4 late type I endoleaks were treated with coil embolization and liquid embolic agents to create a proximal seal between the aortic wall and the endobags. 6,7 The results of this treatment were reportedly successful in the short- and midterm, but again long-term data are crucial to defining whether this treatment is effective in preventing aortic rupture. The importance of treating type I endoleaks after EVAS appears to be the same as after EVAR, with patients in the present series presenting with untreated type I endoleaks and aortic rupture. The rate of reintervention for limb occlusion was low (0.7% within 30 days and 1.1% through 1 year) compared to earlier reports preceding the initiation of the EVAS FORWARD Global registry, 5 likely attributable to learning curve and development of procedural best practices around optimization of the flow lumen. The overall reintervention and aneurysm-related mortality rates in the EVAS FORWARD registry appear to be broadly similar to those described in large EVAR registries 8,9 but in a more anatomically challenging patient cohort. EVAS represents a new concept for the treatment of AAAs and as such might be expected to have some complications unique to the procedure. The use of pressurized endobags to fill the aneurysm sac has the potential risk of injuring the weakened aortic wall and causing intraprocedural aortic injury or rupture. This risk is mitigated by careful observation of the pressure-volume relationship during the endobag fill. In the EVAS FORWARD registry, 1 patient suffered a presumed intraprocedural aortic injury and presented in the postoperative period with a retroperitoneal hematoma that was treated conservatively. There were no intraprocedural aortic ruptures. In addition to the aortic injury, there were 2 iatrogenic iliac artery injuries due to passage of the delivery system through small and calcified iliac arteries. Besides the risk of aortic injury, EVAS has a potential risk of prosthetic infection as the volume of the implant is higher than most, due to the polymer-filled endobags. In the present series, there were 2 conversions due to endograft infection, with 1 case possibly due to an aortoduodenal fistula. Although the occurrence of 2 infections in nearly 300 patients would not be higher than expected, 13 further data will be required to define whether the potential for graft infection is a concern. One point of interest in the EVAS FORWARD registry is related to all-cause mortality, which remains high after aneurysm repair and has changed little in the past 2 decades. 14 Analysis of the EVAR-1 15 and DREAM 16 trials demonstrates that patients undergoing EVAR have a lower early mortality, but all-cause mortality catches up with the group of patients undergoing open surgery after a few years. The catch-up mortality is related principally to cardiovascular and cancer deaths. It has been postulated previously that high cytokine levels that persist after EVAR may contribute to this high cardiovascular mortality. 17 In contrast, EVAS offers a novel methodology of repairing aortic aneurysms and may have a different effect on the aneurysm sac in the postoperative period. In the present study the 12-month all-cause mortality was 5.2%, which is lower than the 7.4% reported in the ENGAGE registry. 8 This finding can be regarded as of only marginal interest at present due to the small number of patients, different period of recruitment, and short follow-up, but a continuing trend of this nature might prompt a comparative evaluation of EVAR and EVAS.

7 Thompson et al 691 Conclusion The present study documents the short and 12-month outcome of EVAS in an unselected group of all-comer patients with challenging aortic morphology. The results at present appear acceptable with regard to perioperative outcomes and complications. The place of EVAS in the armamentarium of techniques to treat AAAs will be further defined by results from centers that are well past their learning curve and the availability of durability data in the longer term. Appendix Investigative Sites and Principal Investigators. Investigative Site Location Principal Investigator Auckland City Hospital Auckland, New Zealand Andrew Holden St George s Hospital London London, UK Matt Thompson Addenbrooke s Cambridge University Hospital Cambridge, UK Paul Hayes Rijnstate Hospital Arnhem, the Netherlands Michel Reijnen Academic Medical Center Amsterdam Amsterdam, the Netherlands Ron Balm St. Elisabeth Hospital Tilburg Tilburg, the Netherlands Jan Heyligers Patrick Vriens St. Antonius Hospital Nieuwegein Nieuwegein, the Netherlands Jean-Paul de Vries Erasmus Medical Center Rotterdam Rotterdam, the Netherlands Hence Verhagen University Hospital Heidelberg Heidelberg, Germany Dittmar Böckler Alfried Krupp Hospital Essen Essen, Germany Thomas Nowak University Hospital Düsseldorf Düsseldorf, Germany Hubert Schelzig Hospital Augsburg Augsburg, Germany Rudolf Jakob Katharinenhospital Stuttgart Stuttgart, Germany Goetz Richter University Hospital Riga Riga, Latvia Dainis Krievins University Hospital Örebro Örebro, Sweden Thomas Larzon University Hospital Stockholm Stockholm, Sweden Linus Blohmé Hospital Kirchberg Luxembourg-Kirchberg, Luxembourg Gaston Schuetz Dirk Grotemeyer Hospital Hamar Hamar, Norway Sven Ross Mathisen Declaration of Conflicting Interests The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Matt Thompson, Paul Hayes, Michel Reijnen, Dittmar Böckler, Jean-Paul de Vries, Dainis Krievins, and Andrew Holden are consultants and members of the scientific advisory board for Endologix. Jan Heyligers is a consultant of Endologix. Funding The author(s) report receiving the following financial support for the research, authorship, and/or publication of this article: The EVAS FORWARD Global Registry was funded by Endologix. References 1. Brownrigg JR, de Bruin JL, Rossi L, et al. Endovascular aneurysm sealing for infrarenal abdominal aortic aneurysms: 30-day outcomes of 105 patients in a single centre. Eur J Vasc Endovasc Surg. 2015;50: Karthikesalingam A, Cobb RJ, Khoury A, et al. The morphological applicability of a novel endovascular aneurysm sealing (EVAS) system (Nellix) in patients with abdominal aortic aneurysms. Eur J Vasc Endovasc Surg. 2013;46: Karthikesalingam A, Holt PJ, Hinchliffe RJ, et al. Risk of reintervention after endovascular aortic aneurysm repair. Br J Surg. 2010;97: McCulloch P, Altman DG, Campbell WB, et al. No surgical innovation without evaluation: the IDEAL recommendations. Lancet. 2009;374: Böckler D, Holden A, Thompson M, et al. Multicenter Nellix EndoVascular Aneurysm Sealing system experience in aneurysm sac sealing. J Vasc Surg. 2015;62: Ameli-Renani S, Das R, Weller A, et al. Embolisation of a proximal type I endoleak post-nellix aortic aneurysm repair complicated by reflux of Onyx into the Nellix endograft limb. Cardiovasc Intervent Radiol. 2015;38: Ameli-Renani S, Morgan RA. Transcatheter embolisation of proximal type 1 endoleaks following endovascular aneurysm sealing (EVAS) using the Nellix device: technique and outcomes. Cardiovasc Intervent Radiol. 2015;38: Stokmans RA, Teijink JA, Forbes TL, et al. Early results from the ENGAGE registry: real-world performance of the Endurant Stent Graft for endovascular AAA repair in 1262 patients. Eur J Vasc Endovasc Surg. 2012;44: Verhoeven EL, Katsargyris A, Bachoo P, et al. Real-world performance of the new C3 Gore Excluder stent-graft: 1-year

8 692 Journal of Endovascular Therapy 23(5) results from the European C3 module of the Global Registry for Endovascular Aortic Treatment (GREAT). Eur J Vasc Endovasc Surg. 2014;48: Sidloff DA, Stather PW, Choke E, et al. Type II endoleak after endovascular aneurysm repair. Br J Surg. 2013;100: Mees B, Voute M, Bastos Goncalves F, et al. Intervention for type II endoleaks? Primum non nocere : appraisal for the conservative management of low-pressure endoleaks after endovascular aneurysm repair. J Cardiovasc Surg (Torino). 2013;54: El Batti S, Cochennec F, Roudot-Thoraval F, et al. Type II endoleaks after endovascular repair of abdominal aortic aneurysm are not always a benign condition. J Vasc Surg. 2013;57: Capoccia L, Mestres G, Riambau V. Current technology for the treatment of infection following abdominal aortic aneurysm (AAA) fixation by endovascular repair (EVAR). J Cardiovasc Surg (Torino). 2014;55: Bahia SS, Holt PJ, Jackson D, et al. Systematic review and meta-analysis of long-term survival after elective infrarenal abdominal aortic aneurysm repair : 5 year survival remains poor despite advances in medical care and treatment strategies. Eur J Vasc Endovasc Surg. 2015;50: United Kingdom EVAR Trial Investigators, Greenhalgh RM, Brown LC, et al. Endovascular versus open repair of abdominal aortic aneurysm. N Engl J Med. 2010;362: De Bruin JL, Baas AF, Buth J, et al.; DREAM Study Group. Long-term outcome of open or endovascular repair of abdominal aortic aneurysm. N Engl J Med. 2010;362: Dawson J, Cockerill G, Choke E, et al. Circulating cytokines in patients with abdominal aortic aneurysms. Ann N Y Acad Sci. 2006;1085: