Results of the Nellix system investigational device exemption pivotal trial for endovascular aneurysm sealing

A Meta-Analysis of Mid-Term Outcomes of Endovascular Aneurysm Sealing

BACKGROUND-AIM

Several studies have been published showing conflicting results on the outcome after endovascular aneurysm sealing (EVAS). The aim of the present study is to conduct a systematic review and meta-analysis of published evidence to assess the efficacy of EVAS in the management of patients with abdominal aortic aneurysm (AAA).

METHODS

An electronic search of the English medical literature, from 2010 to March 2021, was conducted using MEDLINE, EMBASE, and Cochrane databases to find studies relevant to outcome after EVAS.

RESULTS

The final analysis included 12 articles published between 2011 and 2021, including 1440 patients. In total, 79.3% of the included patients underwent aneurysm treatment according to the instructions for use. Technical success was 98.8%. Overall, 30-day mortality was 1.3%. Procedure-related complications were reported in 4% of the cohort. During median follow-up of 28.1 months (range 9-72 months), the pooled estimate of endoleak type I, migration and reinterventions was 16% (95% confidence interval [CI]=7-25), 16% (95% CI=9-23), and 19% (95% CI=11-28), respectively. In a sub-analysis, 7 studies (703 patients) reported outcome with a mean follow-up of more than 2 years (range 24-72 months). In these studies, the pooled estimate of endoleak type I, migration, and reinterventions was 25% (95% CI=13-38), 22% (95% CI=19-26), and 27% (95% CI=21-33), respectively.

CONCLUSION

Patients who have been treated with EVAS are in high risk for reintervention especially beyond 2 years following implantation. Close surveillance for patients treated with EVAS is mandatory.

Feasibility of aortic aneurysm sac embolization using a novel shape memory polymer embolic device

BACKGROUND

We investigated the feasibility of aneurysm sac embolization using a novel self-expanding porous shape memory polymer (SMP) device during endovascular aortic abdominal or thoracic aneurysm repair (EVAR).

METHODS

Retrospective analysis of consecutive patients treated at 2 centers in Germany. Patients were treated from January 2019 to July 2021 with follow-up at 7 days and 3, 6, and 12 months. Aneurysm sacs were implanted with SMP devices immediately following endograft placement during the same procedure. Primary endpoint was technically successful SMP-device deployment into the aneurysm sac outside the endograft. Secondary endpoints were changes in aneurysm volume and associated complications (e.g., endoleaks).

RESULTS

We included 18 patients (16 males), aged 72 ± 9 years, achieving 100% technical success. Mean preprocedure aortic aneurysm sac volume was 195 ± 117 mL with a perfused aneurysm volume of 97 ± 60 mL. A mean of 24 ± 12 SMP devices per patient were used (range 5-45, corresponding to 6.25-56.25 mL expanded embolic material volume). All evaluable patients exhibited sac regression except 2 patients yet to reach 3-month follow-up. At mean 11 ± 7 months (range 3-24), change in aneurysm volume from baseline was -30 ± 21 mL (p < 0.001). In 8 patients, aneurysm regression was observed despite type 2 endoleaks in 6 and type 1A endoleaks in 2, none of them requiring further intervention to date. No morbidity or mortality related to this treatment occurred.

CONCLUSIONS

SMP devices for aortic aneurysm sac embolization during endovascular repair appear feasible and safe in this small case series. Prospective studies are needed.

KEY POINTS

• Shape memory polymer is a novel, self-expanding, porous, and radiolucent embolic device material. • Aortic aneurysm sacs were treated with polymer devices immediately following endograft placement. • Aortic aneurysm sac regression was observed in all patients with over 3-month follow-up. • Aortic aneurysm sac regression was observed even in the presence of endoleaks.

Midterm single-center results after endovascular aneurysm sealing reveal a high rate of stent graft migration, secondary aneurysm ruptures, and device-related reinterventions

OBJECTIVE

To report procedural results and mid-term follow-up outcomes of patients treated with endovascular aneurysm sealing (EVAS) for abdominal aortic disease.

METHODS

In this retrospective observational study, all patients treated with EVAS between March 2013 and January 2018 for abdominal aortic aneurysm (AAA) or abdominal penetrating aortic ulcer were included. The datasets included demographics, aneurysm morphology, and procedural and clinical surveillance outcomes. Furthermore, patients treated within the original instructions for use (IFU-group) were compared with patients treated outside the IFU (non-IFU-group) with regard to survival, reintervention-free survival, freedom from type I endoleak, and freedom from stent graft migration.

RESULTS

Seventy patients were included (67 male; median age, 72.5 years). Sixty-five patients were treated for AAA and 5 patients for abdominal penetrating aortic ulcer. Sixty-nine cases were treated electively (98.6%). Technical success was achieved in 68 cases (97.1%). The median clinical follow-up was 50.5 months (interquartile range, 29.3-62.7 months) with a median computed tomography angiographic follow-up of 38.5 months (interquartile range, 17.1-60.2 months). There were five deaths during the study period (7.1%), four of which were aneurysm related (5.7%). Five secondary AAA ruptures were detected (7.1%). Overall, 25 of 70 patients (35.7%) underwent 35 reinterventions, mostly owing to thrombotic complications (18.6%), stent graft migration (17.1%), and type I endoleak (12.9%). Fifteen patients were treated outside of the IFU (non-IFU-group) (21.4%). The estimated reintervention-free survival for the entire cohort at 30 days and 1, 3, and 5 years was 94.3%, 88.5%, 72%, and 56.9%, respectively. Freedom from stent graft migration at 1, 3, and 5 years was 98.6%, 82.0%, and 47.3%, respectively. The estimated freedom from type I endoleak at 30 days and 1, 3, and 5 years in the IFU-group was 100%, 100%, 94.9% and, 91.1% and significantly different when compared with the non-IFU-group with 79.5%, 72.2%, 72.2%, and 72.2% (P = .012).

CONCLUSIONS

Although the technical and initial results were satisfying, the mid-term results were disappointing. The enforcement of a close follow-up protocol for all patients treated with EVAS, especially vigilant for stent graft migration to prevent secondary type I endoleak and rupture, is strongly recommended.

Open Conversion After Endovascular Aneurysm Sealing: Technical Features and Clinical Outcomes in 44 Patients

Purpose

To evaluate the technical features and clinical results after open conversion for complications following endovascular aneurysm sealing (EVAS).

Materials and Methods

From July 2013 to February 2020, 44 patients (mean age 72±8 years; 36 men) underwent an open conversion due to EVAS complications in a single center. Data were collected on patient characteristics, reasons for conversion, characteristics and duration of the procedure, condition of the polymer, blood loss, time in the intensive care unit (ICU), and intra/postoperative complications. The main outcome measure was mortality at 30 days and in follow-up. Data are presented as the median (IQR) and absolute range.

Results

On average, the open conversion took place 3 years after the initial EVAS implantation [median 37 months (IQR 23, 50); range 0–64]. Most patients were converted due migration (82%), aneurysm growth (77%), and/or endoleak (75%), with 21 patients (48%) having all 3 events. Less frequent diagnoses were aneurysm rupture (n=7), aortic infection (n=3), technical failure during implantation (n=2), and graft thrombosis (n=1). The majority of patients (n=26) were asymptomatic and converted electively, but 9 were operated on urgently and 9 emergently (7 late rupture and 2 due to technical failure). The median procedure duration was 178 minutes (IQR 149, 223; range 87–417), the median blood loss was 1100 mL (IQR 600, 2600; range 300–5000). Polymer degradation was mentioned in the operative reports of 18 cases (41%). Patients stayed a median of 3 days (IQR 2, 7; range 1–35) in the ICU, while the median length of stay in the hospital was 14 days (IQR 10, 20; range 0–93). The 30-day mortality was 23% (n=10). During a median follow-up of 3 months (IQR 0, 11; range 0–38), no additional deaths occurred, but 12 patients suffered from an adverse event. There were 3 cases of wound dehiscence after laparotomy, 2 cases of leg ischemia, 2 cases of renal failure, and individual cases of urinary obstruction, urinoma, paralytic ileus, gastrointestinal bleeding, and postoperative delirium. A non-elective setting was associated with a significantly increased mortality of 33% in urgent cases and 56% in emergent cases (p=0.007). Based on these results an algorithm for the management of EVAS complications was developed.

Conclusion

The significantly increased mortality associated with nonelective conversions highlights the need for active surveillance. The presented algorithm offers a structured tool to avoid emergency conversions.

Predictive Factors and Strategies to Prevent the Development of Type 2 Endoleaks following Endovascular Aneurysm Repair

Type 2 endoleaks are a potential complication of endovascular aortic repair for abdominal aortic aneurysms. They are caused by vessels that have been excluded from the aorta lumen, but may still fill the aneurysm sac due to collateral filling. Type 2 endoleaks may lead to increased morbidity and need for additional procedures. Being able to identify patients at risk for Type 2 endoleaks and prevent them is important for any physician who is performing endovascular aortic repair.

Migration After Endovasclar Aneurysm Sealing in Conjunction With Chimney Grafts

Purpose

To assess the incidence of migration after endovascular aneurysm sealing (EVAS) in conjunction with chimney grafts (chEVAS) for repair of abdominal aortic aneurysms (AAAs).

Materials and Methods

A retrospective, observational cohort study was conducted of 31 patients (mean age 75.7 years; 27 men) treated for juxtarenal AAA between April 2013 and December 2018 at single centers in New Zealand and the Netherlands. The majority of patients received >1 chimney graft (13 single, 13 double, and 5 triple) during chEVAS. Six patients had only the first postoperative scan, so the migration analysis was based on 25 patients.

Results

Median seal length assessed on the first postoperative computed tomography scan was 36.5 mm. The assisted technical success rate was 93.5% with 2 technical failures. Median time to final imaging follow-up was 17 months in 25 patients. At the latest follow-up, there were no cases of caudal migration >10 mm. Freedom from caudal movement of 5 to 9 mm was estimated as 86.1% at 1 year and 73.9% at 2 years; freedom from clinically relevant migration (movement requiring reintervention) was 100% at both time intervals. However, at 3 years there were 2 cases of caudal movement of 5 to 9 mm and a type Ia endoleak warranting reintervention. No correlation between migration and aneurysm growth (p=0.851), endoleak (p=0.562), or the number of chimney grafts (p=0.728) was found. During follow-up, 2 patients (7%) had aneurysm rupture and 10 (33%) had reinterventions. Eight patients (27%) died; 2 were aneurysm-related (7%) and due to the consequences of a reintervention.

Conclusion

In the 2 years following chEVAS, there was no caudal migration >10 mm, but nearly a quarter of patients had caudal movement of 5 to 9 mm. A trend was observed toward ongoing migration that required intervention at 3-year follow-up. chEVAS is technically challenging and should be considered only for patients with no viable alternative treatment option.

Aneurysm Growth After Endovascular Sealing of Abdominal Aortic Aneurysms (EVAS) with the Nellix Endoprosthesis

OBJECTIVE

The aim of this study was to measure the incidence of post endovascular aneurysm sealing (EVAS) abdominal aortic aneurysm (AAA) growth, and its association with stent migration, in a cohort of patients with differing compliance to old and new Instructions For Use (IFU).

METHODS

A retrospective single centre study was conducted to review the computed tomography (CT) and clinical data of elective, infrarenal EVAS cases, performed as a primary intervention, between December 2013 and March 2018. All included patients had a baseline post-operative CT scan at one month and at least one year follow up. The primary outcome measure was the incidence of AAA growth and its association with stent migration. AAA growth was defined as a ≥5% increase in aortic volume between the lowermost renal artery and the aortic bifurcation post EVAS at any time during follow up, in comparison to the baseline CT scan. Migration was defined according to the ESVS guidelines, as > 10 mm downward movement of either Nellix stent frame in the proximal zone.

RESULTS

Seventy-six patients were eligible for inclusion in the study (mean age 76 ± 7.4 years; 58 men). AAA growth was identified in 50 of 76 patients (66%); adherence to IFU did not affect its incidence (mean growth within IFU-2016 compliant cohort vs. non-compliant: 16% vs. 13%, p = .33). Over time, the incidence of AAA growth increased, from 32% at one year to 100% at four years. AAA growth by volume was progressive (p < .001), as its extent increased over time. Migration was detected in 16 patients and there was a statistically significant association with AAA growth (13 patients displayed migration and AAA growth, p = .036).

CONCLUSION

Patients treated with EVAS are prone to AAA growth, irrespective of whether their aortic anatomy is IFU compliant. AAA growth by volume is associated with stent migration. Clinicians should continue close surveillance post EVAS, regardless of whether patients are treated within IFU.

Endovascular Aneurysm Sealing is Associated with Higher Medium-Term Survival than Traditional EVAR

BACKGROUND

Endovascular aneurysm repair (EVAR) is the dominant treatment modality for abdominal aortic aneurysm (AAA). Periprocedural risks are low, and cardiovascular events are the principle determinants of long-term survival. Recently, the concept of endovascular aneurysm sealing (EVAS) has been introduced into clinical investigation. In previous cohort studies, EVAS has been associated with a lower all-cause mortality than expected despite device issues. We used a propensity weighted approach to investigate whether EVAS was associated with lower all-cause mortality after aneurysm repair.

METHODS

We compared 333 patients in the Nellix United States Investigational Device Exemption trial to 15,431 controls from the Vascular Quality Initiative between 2014 and 2016 after applying the exclusion criteria from the investigational device exemption (hemodialysis, creatinine > 2.0 mg/dL, or rupture). We calculated propensity scores and applied inverse probability weighting to compare risk adjusted medium-term survival using Kaplan-Meier and Cox regression.

RESULTS

After weighting, patients treated with the Nellix EVAS system experienced higher 3-year survival than controls from the Vascular Quality Initiative (93% vs. 88%, respectively). This corresponded to a 41% lower risk of mortality for EVAS compared with EVAR (HR 0.59 [0.38-0.92], P = 0.02). Subgroup analysis demonstrated that the association between EVAS and higher survival was strongest in the subgroup of patients with aneurysms over 5.5 cm (P for interaction < 0.001). In this subgroup, EVAS patients experienced half the rate of mortality as those patients treated with EVAR, with 3-year survival of 92% compared with 86% (HR 0.5 [0.3-0.9], P = 0.02).

CONCLUSIONS

In this select group of patients, EVAS was associated with higher medium-term survival than traditional EVAR. Although issues with the device have recently surfaced, this exploratory analysis shows that the concept of sac sealing may hold promise. Further study is needed to confirm this finding and determine whether EVAS is associated with lower rates of cardiovascular events.

Techniques and future perspectives for the prevention and treatment of endoleaks after endovascular repair of abdominal aortic aneurysms

The presence of endoleaks remains one of the main drawbacks of endovascular repair of abdominal aortic aneurysms leading to the increase of the size of the aneurysmal sac and in most of the cases to repeated interventions. A variety of devices and percutaneous techniques have been developed so far to prevent and treat this phenomenon, including sealing of the aneurysmal sac, endovascular embolisation, and direct sac puncture. The aim of this review is to analyse the indications, the effectiveness, and the future perspectives for the prevention and treatment of endoleaks after endovascular repair of abdominal aortic aneurysms.

Type 2 Endoleak Incidence and Fate After Endovascular Aneurysms Repair in a Multicentric Series: Different Results with Different Devices?

BACKGROUND

The aim of this work is describing incidence and fate of type 2 endoleaks (T2ELs) in a multicentric cohort of patients treated by endovascular aneurysms repair using the Ovation device (Endologix) and comparing them with a group treated using the Excluder (W. L. Gore & Associates).

METHODS

This is a retrospective study conducted on 261 patients treated using the Ovation device and 203 using the Excluder. Outcomes were intraprocedural, 30-day, 12-month, and mean time follow-up T2EL incidence and related reinterventions. Patent inferior mesenteric artery (IMA), ≥3 lumbar arteries (LAs), intrasac thrombus volume, the mean diameter of common and external iliac arteries, external iliac artery stenosis (>70%), diameter ≤5 mm, iliac tortuosity ratio ≤0.5, thrombosis, and calcification were noted and considered as potentially influencing outcomes.

RESULTS

Patients of the Ovation group presented significantly more thrombosed, calcified, and tortuous iliac vessels than those in the Excluder group. No significant differences were noted in sac thrombosis, IMA, and LA patency. At completion angiography, T2EL was evident in 57 Ovation and 46 Excluder patients (P = 0.832). At 1 month, it was evident in 33 Ovation group and 28 Excluder group patients (P = 0.726). At 12-month and mean time (30.14 months) follow-up, no differences were evident between the 2 groups (P = 0.940 and 0.951, respectively). The log-rank test showed that the rate of T2EL-related reintervention was not different between the 2 groups (P = 0.46). Regarding anatomical characteristics, a statistically significant difference was not observed between patients presenting or not with T2EL (P > 0.05).

CONCLUSIONS

Data showed no significant differences in terms of T2EL incidence between the 2 study groups. None of preoperative anatomical features were found to be significantly associated with the appearance of T2EL.

Stent Frame Movement Following Endovascular Aneurysm Sealing in the Abdominal Aorta

Purpose: To investigate the incidence and extent of stent frame movement after endovascular aneurysm sealing (EVAS) in the abdominal aorta and its relationships to aneurysm growth and the instructions for use (IFU) of the Nellix endograft. Methods: A retrospective single-center study was conducted to review the clinical data and computed tomography (CT) images of 75 patients (mean age 76±7.6 years; 57 men) who underwent infrarenal EVAS and had a minimum 1-year follow-up. The first postoperative CT scan at 1 month and the subsequent scans were used to measure the distances between the proximal end of the stent frames and a reference visceral vessel using a previously validated technique. Device migration was based on the Society of Vascular Surgery definition of >10-mm downward movement of either Nellix stent frame in the proximal landing zone; a more conservative proximal displacement measure (downward movement ⩾4 mm) was also recorded. Patients were categorized according to adherence to the old (2013) or new (2016) Nellix IFU. Aneurysm diameter was measured for each scan; a change ⩾5 mm was deemed indicative of aneurysm growth. Results: Over a median follow-up of 24 months (range 12–48), proximal displacement ⩾4 mm occurred in 42 (56%) patients and migration >10 mm in 16 (21%), with similar incidences in the right and left stent frames. Proximal displacement was significantly more frequent among patients whose anatomy did not conform to any IFU (p=0.025). Presence of aneurysm growth ⩾5 mm was observed in 14 (19%) patients and was significantly associated with proximal displacement ⩾4 mm (p=0.03). Conclusion: Infrarenal EVAS may be complicated by proximal displacement and migration, particularly when performed outside the IFU. The definition of migration used for endovascular aneurysm repair may be inappropriate for EVAS; a new consensus on definition and measurement technique is necessary.

A Comparison of Manual and Three-Dimensional Modalities in Predicting Nellix Polymer Volume

Purpose

Achieving an effective seal with the Nellix endovascular aneurysm system is dependent on filling the stent bags with an appropriate volume of polymer. Calculating this volume preoperatively is essential and can be performed manually or using three-dimensional (3D) software. The aim of this project was to compare the accuracy of these two methods relative to the actual polymer volume used.

Materials and Methods

Consecutive patients undergoing Nellix aneurysm repair were included in this retrospective study. Operation notes were analysed for the polymer volume used intra-operatively. Predicted volumes for all patients had been calculated on picture archiving and communication system (PACS) using a manual ‘segmental cylinder’ method. Computed tomography angiograms were then re-analysed using the Synapse 3D PACS update. The difference between groups was assessed using a paired t-test.

Results

Twenty-eight patients were included in the analysis; 26 men (92.9%) and 2 women (7.1%); median age 80.9 years (interquartile range, 72.5–84.5 years). The mean volume of polymer used was 103 mL. The mean manual-derived prediction was 100.1 mL (P=0.365) and 3D-derived prediction 110.2 mL (P<0.001). Manual prediction led to an average 2.8% underestimate of polymer volume whilst 3D prediction led to an average 7.0% overestimate.

Conclusion

Calculating predicted polymer volume for the Nellix system is more accurate using a manual approach then the 3D alternative. Whilst this method is more time-consuming, there is no significant difference when compared to the actual volume used. Quicker 3D software predictions can be utilised, but their tendency to overestimate should be recognized and taken into account during planning.

Identifying and addressing the limitations of EVAR technology

INTRODUCTION

Endovascular aortic repair (EVAR) has improved over the last two decades. Approximately 80% of the patients presenting with an abdominal aortic aneurysm (AAA) is nowadays primarily treated with EVAR.

AREAS COVERED

In this review, the differences between endovascular and open repair, the clinical characteristics needed for EVAR, the role of clinical imaging and the developments in EVAR technology will be discussed. Early mortality is lower in EVAR as compared to open repair, whereas this benefit is lost after 3 years postoperatively. EVAR comes with a high reintervention rate, with endoleak being the most important predictive factor for reintervention. Expanding technical possibilities have allowed surgeons to choose from a palate of endovascular approaches in aneurysm patients with challenging anatomies.

EXPERT COMMENTARY

Although EVAR has taken a giant leap forward in development, the new developments have seemed to surpass the long-term limitations with older devices. It is important to start focusing on the current limitations of EVAR, in particular the durability of devices in the human variable anatomic and dynamic environment.

Comparison of endovascular aneurysm sealing and repair with respect to contrast use and radiation in comparable patient cohorts

BACKGROUND

Due to recent advances in endograft design and percutaneous access, technical success could be increased during endovascular aneurysm repair (EVAR). Beside EVAR, endovascular aneurysm sealing (EVAS) provides an alternative procedure to treat aneurysms. To compare the two methods, additional benchmark criteria should be evaluated: Screening time, dose area product (DAP), procedure time and contrast use. In this study these technical variables are analyzed for EVAS vs. EVAR in comparable patient cohorts.

METHODS

It is a retrospective, single-center study. Only elective cases of infrarenal aortic aneurysms were included, all treated by the same surgeon (D.B.). Procedures were performed within the instructions for use without additional procedures. All operations were undertaken in a hybrid operating theatre. For EVAR, only the Medtronic Endurant® and the Gore C3 Excluder® were included. For EVAS the Nellix® from Endologix was used.

RESULTS

Between 2012 and 2016, 67 patients were treated with EVAS and 40 with EVAR; of these 20 and 16 could be introduced into the study respectively. Median age was 73 and 72 years respectively (only men). The two groups were comparable in terms of BMI, GFR and ASA-status. Screening time was reduced for EVAS (10.6 vs. 14.5 min., P<0.01), while the DAP was not significantly different. Procedural time and contrast use were increased for EVAS (120 vs. 96 min., 120 vs. 79 mL, P<0.01).

CONCLUSIONS

Especially the younger EVAS-procedure requires ongoing review in order to further reduce contrast agent. Reduced screening time for EVAS does not have a significant impact on radiation dose.

Deformation and dynamic response of abdominal aortic aneurysm sealing

Endovascular sealing is a new technique for the repair of abdominal aortic aneurysms. Commercially available in Europe since 2013, it takes a revolutionary approach to aneurysm repair through minimally invasive techniques. Although aneurysm sealing may be thought as more stable than conventional endovascular stent graft repairs, post-implantation movement of the endoprosthesis has been described, potentially leading to late complications. The paper presents for the first time a model, which explains the nature of forces, in static and dynamic regimes, acting on sealed abdominal aortic aneurysms, with references to real case studies. It is shown that elastic deformation of the aorta and of the endoprosthesis induced by static forces and vibrations during daily activities can potentially promote undesired movements of the endovascular sealing structure.

Deformation and dynamic response of abdominal aortic aneurysm sealing

Endovascular sealing is a new technique for the repair of abdominal aortic aneurysms. Commercially available in Europe since 2013, it takes a revolutionary approach to aneurysm repair through minimally invasive techniques. Although aneurysm sealing may be thought as more stable than conventional endovascular stent graft repairs, post-implantation movement of the endoprosthesis has been described, potentially leading to late complications. The paper presents for the first time a model, which explains the nature of forces, in static and dynamic regimes, acting on sealed abdominal aortic aneurysms, with references to real case studies. It is shown that elastic deformation of the aorta and of the endoprosthesis induced by static forces and vibrations during daily activities can potentially promote undesired movements of the endovascular sealing structure.

Preliminary results of endovascular aneurysm sealing from the multicenter Italian Research on Nellix Endoprosthesis (IRENE) study

OBJECTIVE

Because of advances in technology and experience of the operator, endovascular aneurysm repair (EVAR) has supplanted open repair to treat abdominal aortic aneurysm (AAA). The low 30-day mortality and morbidity of EVAR make the endovascular approach particularly suitable for patients at high surgical risk. However, endoleak or endograft migration requiring secondary intervention or open surgical conversion is a limitation of EVAR. The Nellix system (Endologix, Inc, Irvine, Calif) has been designed to seal the entire AAA to overcome these limitations with EVAR. We report the results of a retrospective, multicenter study with endovascular aneurysm sealing (EVAS) aimed to assess technical success, procedure-related mortality, complications, and reinterventions.

METHODS

This study included patients selected for elective treatment with the Nellix device per the endovascular repair protocol at 16 Italian vascular centers. All patients were enrolled in a postoperative surveillance imaging program including duplex ultrasound investigations, computed tomography, and magnetic resonance controls following local standards of care.

RESULTS

From 2013 to 2015, there were 335 patients (age, 75.5 ± 7.4 years; 316 men) who underwent elective EVAS. In 295 cases (88.0%), EVAS was performed under standard instructions for use of the Nellix system. Preoperative aneurysm diameter was 55.5 ± 9.4 mm (range, 46-65 mm). The inferior mesenteric artery and lumbar arteries emerging from the AAA were patent in 61.8% and 81.3% of cases, respectively. Chimney grafts were electively carried out in eight cases (2.4%). One (0.3%) intraprocedural type IB endoleak was observed and promptly corrected. Device deployment was successful in all patients, with no perioperative mortality. Early (≤30 days) complications included 1 (0.3%) type IA endoleak, 2 (0.6%) type II endoleaks (0.6%), 2 (0.6%) stent occlusions (0.6%), 3 (0.9%) distal embolizations, and 2 (0.2%) femoral artery dissections. Six (2.9%) patients underwent reinterventions. At 1-year follow-up, complications included 3 (1.1%) type II endoleaks, 4 (1.4%) type IA endoleaks, 1 (0.3%) type IB endoleak, 2 (0.7%) distal stent migrations, 5 (1.8%) distal embolizations, and 1 (0.3%) stent occlusion. Twelve patients (3.7%) underwent reinterventions, including four (1.4%) surgical conversions due to aortoduodenal fistula (1), endograft infection (1), and type IA endoleak that was unsuccessfully treated percutaneously (2). Two AAA-related deaths occurred. Freedom from aneurysm-related reintervention was 98.3% at 1-month and 94.7% at 12-month follow-up.

CONCLUSIONS

The preliminary results of this real-world multicenter study showed that EVAS with Nellix for the management of AAAs appears feasible. This device platform is associated with acceptable procedure-related mortality and low overall complication and reintervention rates. Definitive conclusions on the value of this novel device await long-term follow-up data.

Determination of Stent Frame Displacement After Endovascular Aneurysm Sealing

Purpose: To describe and validate a new methodology for visualizing and quantifying 3-dimensional (3D) displacement of the stent frames of the Nellix endosystem after endovascular aneurysm sealing (EVAS). Methods: The 3D positions of the stent frames were registered to 5 fixed anatomical landmarks on the post-EVAS computed tomography (CT) scans, facilitating comparison of the position and shape of the stent frames between consecutive follow-up scans. Displacement of the proximal and distal ends of the stent frames, the entire stent frame trajectories, as well as changes in distance between the stent frames were determined for 6 patients with >5-mm displacement and 6 patients with <5-mm displacement at 1-year follow-up. The measurements were performed by 2 independent observers; the intraclass correlation coefficient (ICC) was used to determine interobserver variability. Results: Three types of displacement were identified: displacement of the proximal and/or distal end of the stent frames, lateral displacement of one or both stent frames, and stent frame buckling. The ICC ranged from good (0.750) to excellent (0.958). No endoleak or migration was detected in the 12 patients on conventional CT angiography at 1 year. However, of the 6 patients with >5-mm displacement on the 1-year CT as determined by the new methodology, 2 went on to develop a type Ia endoleak in longer follow-up, and displacement progressed to >15 mm for 2 other patients. No endoleak or progressive displacement was appreciated for the patients with <5-mm displacement. Conclusion: The sac anchoring principle of the Nellix endosystem may result in several types of displacement that have not been observed during surveillance of regular endovascular aneurysm repairs. The presented methodology allows precise 3D determination of the Nellix endosystems and can detect subtle displacement better than standard CT angiography. Displacement >5 mm on the 1-year CT scans reconstructed with the new methodology may forecast impaired sealing and anchoring of the Nellix endosystem.

Evolution of Computed Tomography Imaging the First Year after Endovascular Sealing of Infrarenal Aortic Aneurysms Using the Nellix Device

BACKGROUND

The Nellix endovascular aneurysm sealing (EVAS) system is an alternative endovascular treatment option for infrarenal aortic aneurysms (AAAs), with a unique appearance on computed tomography angiography (CTA). Normal evolution of post-EVAS CTA appearance follow-up is still largely unknown and important to timely detect eventual complications. The objective is to assess the normal appearance of CTA images 30 days and 1 year after EVAS in 50 consecutive patients.

METHODS

Fifty patients treated with Nellix EVAS for an infrarenal AAA were included from 3 hospitals. Using dedicated software, a total of 150 CTA scans were analyzed by predetermined variables per anatomical segment.

RESULTS

Thirty days post-EVAS, there was a slight, but not statistically significant, increase in AAA diameter that returned to the preoperative value after 1 year. A shift in total aortic volume distribution was observed without changing aortic diameter, including a trend toward a decreased thrombus volume (85.6 ± 49.1 mL and 78.8 ± 35.5 mL at 30 days and 1 year, respectively, P < 0.242) and a slight, but statistically significant, increase in polymer volume (68.2 ± 34.1 mL and 71.9 ± 35.2 mL at 30 days and 1 year, respectively, P < 0.001). The β-angle (P = 0.06) and iliac artery angulation (P < 0.001) decreased after implant. The latter returned to its original state after 1 year, whereas the neck straightening remained. Over time, there was a significant decrease in radiodensity in the middle of the polymer-filled endobags with an increase at its edges (P < 0.05). Thrombus radiodensity significantly increased over the first year (P < 0.05). Diameters of the infrarenal neck and common iliac arteries remained unchanged, no endoleaks were observed, and the position of the device was stable.

CONCLUSIONS

Change of CT appearance after EVAS is unique, and as such, the judgment of these images requires experience. The appearance of the endobags in respect to volume and radiodensity differ from classic EVAR. Normal changes over time are observed in aortoiliac angulation, volumes, and radiodensities.

Aortic Foreign Body Caused by Rupture of Endobag after EVAS Using the Nellix Aneurysm Sealing System-A Case Report

The Nellix aneurysm sealing system aims at sealing the cavity of the sac of the aneurysm, to reduce typical complications such as migration or endoleak. We report on a case of a unique device-associated complication: rupture and displacement of the filling material into the aortic lumen, causing peripheral ischemia and imminent renal and visceral occlusion, in a patient with anastomotic ulcer after an open aortobiiliac bypass and calcified and tortuous iliac arteries. The material was removed by open surgery. The patient recovered completely. The device should be handled with great caution in cases with hostile access routes, and in secondary interventions.

Aneurysm sealing

Compulsory registration needed

Patient selection for endovascular sac sealing of abdominal aortic aneurysm

Endovascular sealing is a developing technique for treatment of abdominal aortic aneurysm that draws on novel concepts utilizing polymer filling of endobags within the aorto-iliac lumen. The morphologic indications and patient selection, while similar to those of endovascular aneurysm repair, differ in some regards. The Instructions for Use for the Nellix sealing device may expand the indications for aneurysm treatment and are closely scrutinized in this article. The authors draw on current evidence and their own experience and opinion in the discussion around appropriate patient selection and its influence on outcomes after endovascular aneurysm sealing. A recommendation for stricter adherence to Instructions for Use in the early phase of clinical experience is made, with acknowledgement that the natural evolution of endovascular aneurysm sealing may involve more challenging cases.

Clinical outcomes after Nellix Endovascular Aneurysm Sealing

The published evidence on clinical outcomes of Nellix Endovascular Aneurysm Sealing for elective abdominal aortic aneurysm repair has confirmed low procedural morbidity and reintervention rate. This early clinical experience with Nellix is encouraging, despite the device and procedural steps being in evolution, and patients being treated outside of the recommended instructions for use. The long-term follow-up of a treated patient cohort is now available and demonstrates low aneurysm-related mortality and morbidity. The initial experience with the commercially available Nellix device was captured in a multicenter report involving 171 patients and two independently monitored, company-sponsored device registries (EVAS Forward Global Trial and Forward US Investigational Device Exemption Trial). All three clinical studies report a 99% procedural technical success, low mortality, and persistent endoleak rate with re-intervention rates comparable to conventional EVR device registries. Nellix EVAS is applicable to a range of aneurysm anatomies, including patients with isolated of concomitant iliac artery aneurysms. The post-procedural imaging appearances after Nellix EVAS are unique due to the AAA sac polymer, change with time, but are now well understood.

Endovascular abdominal aortic aneurysm sealing: A systematic review of early outcomes

Objectives

There has been a clear move towards endovascular repair of abdominal aortic aneurysms owing to better peri-operative outcomes compared with open surgical repair. However, follow-up has continued to reveal relatively high rates of endoleaks and re-interventions. Improvements in endovascular stent-grafts aim to decrease these complications. This systematic review aims to determine the early outcomes of abdominal aortic aneurysm sealing.

Methods

Standard PRISMA guidelines were followed. A literature search was performed with the aim to extract any publication related to the endovascular aneurysm sealing device.

Results

The total number of patients in this systematic review of 11 studies is 684, with a mean age of 73.2 years, and 587 (88.0%) males. The majority were undergoing elective procedures ( n = 606, 91.0%), the remainder as emergencies ( n = 30, 4.5% as ruptures, n = 30, 4.5% as symptomatic). Technical success rate including emergency cases was 99.1%. Thirty-day mortality rate was 2.6% ( n = 17) including all cases, and 1.0% ( n = 6) including elective cases only. Thirty -day endoleak detection rate was 4.7% ( n = 31) including all cases, and 4.8% ( n = 29) including elective cases only. Thirty-day aneurysm-related re-intervention rate was 5.7% ( n = 38) including all cases, and 4.6% ( n = 28) including elective cases only. There was no conversion to open surgery within 30 days post-op in the elective cases. There were three delayed conversions to open surgery within 30 days and one report of stent migration causing rupture in the emergency setting.

Conclusions

This novel endovascular aneurysm-sealing device for abdominal aortic aneurysm repair has shown respectable early outcomes. Good technical success rates, in both elective and emergency settings, low rates of all-type endoleaks and low re-intervention rates have all been demonstrated. It is proving to be a safe alternative to open and endovascular aneurysm repair; however, longer term follow-up results are needed to assess the safety and effectiveness of the device in the long term.

One-year pivotal trial outcomes of the Nellix system for endovascular aneurysm sealing

OBJECTIVE

The Nellix EndoVascular Aneurysm Sealing (EVAS) System (Endologix, Inc, Irvine, Calif) is a novel approach to abdominal aortic aneurysm (AAA) treatment whereby polymer is used to fill the AAA sac. We report 1-year results of the investigational device exemption pivotal trial.

METHODS

Eligible patients were treated at 30 sites in the United States and Europe. Inclusion criteria required an asymptomatic infrarenal AAA, with a neck length ≥10 mm and ≤60° angle, iliac artery blood lumen diameter 9 to 35 mm, access artery diameter ≥6 mm, and serum creatinine ≤2 mg/dL. Follow-up included computed tomography angiography scans at 30 days, 6 months, and 1 year that were evaluated by a core laboratory. The primary safety end point was 30-day major adverse events (MAEs), which were compared with a performance goal of <56% (the Society for Vascular Surgery open repair control group rate). The primary effectiveness end point was treatment success at 1 year, which was compared with a performance goal of >80%. Treatment success required procedural technical success and absence of AAA rupture during follow-up, conversion to open surgical repair, endoleak (type I or III) at 1 year, migration >10 mm causing complications or requiring secondary intervention, aneurysm enlargement, or secondary procedures through 1 year for resolution of endoleak, device obstruction or occlusion, or device defect.

RESULTS

Of 150 treated patients, 149 (99.3%) completed 1-year follow-up. The MAEs rate at 30 days was 2.7% (95% confidence interval, 0.7%-6.7%), satisfying the primary safety end point (<56%). The 1-year treatment success was 94% (95% confidence interval, 88.6%-97.4%), achieving the primary effectiveness end point (>80%). At 1 year, key secondary outcomes included 6.7% MAEs, 4.7% serious device-related events, 1.3% AAA-related mortality, 3.7% secondary interventions, and 0.7% surgical conversions. MAEs through 1 year included death (n = 6), stroke (n = 3), bowel ischemia (n = 2), renal failure (n = 2), respiratory failure (n = 2), and myocardial infarction (n =1). One iatrogenic AAA rupture occurred and one AAA rupture was reported during follow-up. AAA sac enlargement (>5 mm) was 1.5% at 1 year. Endoleaks were present in four patients (3.1%) at 1 year (1 type Ib and 3 type II). Migration >10 mm occurred in three patients (2.3%), but none required secondary intervention.

CONCLUSIONS

Outcomes with this novel endovascular therapy for AAA, the Nellix EVAS System, are encouraging. The primary safety and effectiveness end points have been met. Low morbidity, low mortality, and high procedural and treatment success were achieved despite the inevitability of a learning curve and unique risks associated with a new device and technique. Long-term follow-up is in progress.

Feasibility and Technical Aspects of Proximal Nellix-in-Nellix Extension for Late Caudal Endograft Migration

Purpose: To describe the feasibility and technical aspects of a proximal Nellix-in-Nellix extension to treat caudal stent-graft migration after endovascular aneurysm sealing (EVAS) in the in vitro and in vivo settings. Methods: In vitro studies were designed (1) to assess inner diameters of Nellix-in-Nellix extensions after postdilation with 12-mm balloons and (2) to test wall apposition in tubes with different diameters using a Nellix-in-Nellix stent-graft that extended out of the original Nellix stent-graft lumen by 10, 20, 30, and 40 mm. Simulated-use experiments were performed using silicone models in conjunction with a pulsatile flow pump. In the clinical setting, 5 patients (median age 74 years, range 73–83) presented at 2 centers with type Ia endoleak secondary to caudal Nellix stent-graft migration measuring a median 9 mm (range 7–15) on the left and 7 mm (range 0-11) on the right. Median polymer fill volume at the initial EVAS procedure was 42.5 mL (range 25–71). The median time to reintervention with a proximal Nellix extension was 15 months (range 13–32). Results: In vitro, the inner diameters of the Nellix-in-Nellix extensions were consistent after postdilation. Cases with 10 and 20 mm of exposed endobag resulted in a poor seal with endoleak, while cases with 30 and 40 mm of exposed endobag length exhibited angiographic seal. Fill line pressures of the second Nellix were higher than expected. In the 5 clinical cases, chimney grafts were required in each case to create an adequate proximal landing zone. The Nellix-in-Nellix procedure was successful in all patients. There were no procedure-related complications, and no endoleaks were observed during a median 12-month follow-up. Reinterventions were performed in 2 patients because of in-stent stenosis and chimney graft compression, respectively. Conclusion: Proximal Nellix-in-Nellix extension can be used to treat caudally migrated Nellix stent-grafts and to treat the consequent type Ia endoleak, but the technique differs from primary EVAS. The development of dedicated proximal extensions is desirable.

Three-Dimensional Analysis of Component Stability of the Nellix Endovascular Aneurysm Sealing System After Treatment of Infrarenal Abdominal Aortic Aneurysms

Purpose: To assess short-term stability and conformational changes of the Nellix EndoVascular Aneurysm Sealing (EVAS) System using 3-dimensional (3D) analysis. Methods: Postoperative computed tomography (CT) scans obtained at 0, 3, and 12 months in 24 patients (mean age 75±7 years; 22 men) who underwent EVAS between December 2013 and December 2014 for intact abdominal aortic aneurysm (within the instructions for use) were evaluated for stent-graft deviation in multiple planes using dedicated 3D analysis software. In addition, 2D analysis using an anatomically fixed reference landmark was performed to assess craniocaudal migration. Clinical and follow-up data of the patients were recorded and matched with results of the imaging analysis. Results: Overall stability of the Nellix endografts was promising. Relevant conformational changes in the majority of cases were limited to the iliac graft segment and were clinically benign in all cases. Conversely, the only deviation of the proximal stent-graft segment was found in a patient with type Ia endoleak. Additional 2D analysis found relevant (≥5 mm) caudal migration of the Nellix stent-graft in 6 patients, including the one with the type Ia endoleak. In 3 patients, 3D analysis demonstrated the absence of relevant conformational changes of the endografts despite caudal migration. Conclusion: Overall stability of the separate EVAS stent-grafts is promising in the short term. Relevant conformational changes (stent-graft deviation) in the majority of cases were benign and confined to the iliac segment.

Secondary interventions after endovascular aneurysm sac sealing: endoleak embolization and limb-related interventions

The Nellix endovascular aneurysm sealing system is a novel alternative to conventional endovascular aneurysm repair for aortic aneurysm management using paired balloon expandable endografts supported by polymer-filled endobags to achieve sealing and anatomic fixation. Part of the promise of endovascular aneurysm sealing is increased resistance to lateral and longitudinal forces and thus a potential for reduced rates of device-related failures, particularly endoleaks. Initial efficacy data on this device are encouraging, but our knowledge of its associated complications and their management is limited. Reported adverse events include Type 1 and 2 endoleaks, graft stenosis and occlusion. The aim of this article is to review the early experience of endovascular aneurysm sealing focusing on the incidence, significance, and management of device-related complications.

Endovascular Aneurysm Sealing (EVAS) and Chimney EVAS in the Treatment of Failed Endovascular Aneurysm Repairs

PURPOSE

To assess the technical success and clinical outcome of reinterventions using the Nellix Endovascular Aneurysm Sealing (EVAS) System to treat complications after endovascular aneurysm repair (EVAR).

METHODS

Fifteen consecutive patients (mean age 79 years; 14 men) with prior EVAR were treated with EVAS between March 2014 and December 2015 at 2 institutions. The failed prior EVARs included 13 bifurcated endografts, 1 bifurcated graft plus fenestrated cuff, and 1 tube endograft. Endoleaks were the predominant indications: type Ia in 10 and type III in 5 (3 type IIIa and 2 type IIIb). All patients presented with progressive aortic aneurysms (median 7.85-cm diameter; range 6.5-11). Eight patients were treated on an urgent or emergency basis (6 symptomatic aneurysms and 2 contained ruptures). All patients underwent Nellix relining of the failed stent-graft; 10 had chimney (Ch) procedures in combination with EVAS (chEVAS) because the proximal landing zones were inadequate.

RESULTS

Technical success was 100%. All endoleaks were successfully sealed, and no additional intervention was required. No further endoleak after EVAS or chEVAS was recorded. Endobag protrusion occurred in 1 case without sequelae. One elderly patient with ruptured aneurysm died from multiple organ failure 2 months postoperatively. One renal artery guidewire injury led to nephrectomy because of active bleeding. No reinterventions, aneurysm-related mortalities, graft thrombosis, endoleaks, or chimney graft occlusions were observed during a median follow-up of 8 months (range 3-24).

CONCLUSION

The present preliminary experience demonstrates that the use of EVAS/chEVAS is feasible for treatment of failed EVAR. This technique may be used as bailout or an alternative treatment when other established methods are infeasible or not available.

Extended use of endovascular aneurysm sealing for ruptured abdominal aortic aneurysms

Endovascular repair of abdominal aortic aneurysms (EVAR) is now an established treatment modality for suitable patients presenting with aneurysm rupture. EVAR for ruptured aneurysms reduces transfusion, mechanical ventilation, intensive care. and hospital stay when compared with open surgery. In the emergency setting, however, EVAR is limited by low applicability due to adverse clinical or anatomical characteristics and increased need for reintervention. In addition, ongoing bleeding from aortic side branches post-EVAR can cause hemodynamic instability, larger hematomas, and abdominal compartment syndrome. Endovascular aneurysm sealing, based on polymer filling of the aneurysm, has the potential to overcome some of the limitations of EVAR for ruptured aneurysms and to improve outcomes. Recent literature suggests that endovascular aneurysm sealing can be performed with early mortality similar to that of EVAR for ruptured aortic aneurysms, but experience is limited to a few centers and a small number of patients. The addition of chimney grafts can increase the applicability of endovascular aneurysm sealing in order to treat short-neck and juxtarenal aneurysms as an alternative to fenestrated endografts. Further evaluation of the technique, with larger longitudinal studies, is necessary before advocating wider implementation of endovascular aneurysm sealing in the emergency setting.

The Nellix™ EndoVascular sealing system in patients with abdominal aortic aneurysms in conjunction with iliac artery occlusive disease

Introduction Concomitant abdominal aortic aneurysm formation and aortoiliac occlusive disease is a challenging combination, often requiring open reconstructive surgery. In this study, we have assessed a single center experience of the Nellix EndoVascular Aneurysm Sealing System in the treatment of an abdominal aortic aneurysm in conjunction with iliac artery occlusive disease. Methods Retrospectively case files of patients treated with Nellix EndoVascular Aneurysm Sealing System in a single center were reviewed. The primary endpoints of the study were the technical success of Nellix EndoVascular Aneurysm Sealing System in patients with coincidental iliac artery occlusive disease and the successful exclusion of the aneurysm during follow-up. Results Of the 96 patients that were treated with Nellix EndoVascular Aneurysm Sealing System, five were identified that had an abdominal aortic aneurysm in conjunction with iliac artery occlusive disease. Treated patients had either unilateral (n = 4) or bilateral (n = 1) common iliac artery occlusive disease varying from 70% stenosis to complete occlusions. The lesion length varied from 5 to 50 mm and in two cases it involved an occluded bare metal stent. The indication for surgery was the abdominal aortic aneurysm in all patients, including three also suffering from claudication. In all patients the iliac artery occlusive disease was pretreated with balloon-expandable covered stents. Technical success was achieved in all five patients. After a median follow-up of nine months all stents were patent with no signs of endoleak and stable aneurysm diameters. All patients were free of intermittent claudication or ischemic wounds. Conclusion Nellix EndoVascular Aneurysm Sealing System seems feasible and safe in patients with a combination of abdominal aortic aneurysm and iliac artery occlusive disease.

Midterm Outcomes of the Nellix Endovascular Aneurysm Sealing System: A Dual-Center Experience

PURPOSE

To report midterm outcomes of the Nellix Endovascular Aneurysm Sealing (EVAS) System in the treatment of abdominal aortic aneurysm (AAA).

METHODS

Between September 2013 and July 2014, 64 AAA patients (mean age 76.6±6.8 years; 61 men) were treated with the EVAS system at 2 centers (only procedures performed at least 12 months prior to the analysis were included). Most patients were treated for a stable AAA, while 1 patient was treated for a ruptured aneurysm. Mean aneurysm diameter was 57.3±9.3 mm. The proximal neck measured a mean 21.5±3.3 mm in diameter and 27.0±12.1 mm long; the neck angle was 16.9°±19.3°. Eleven (17.2%) patients were treated outside the instructions for use (IFU).

RESULTS

Technical success was achieved in 63 (98.4%) of 64 patients; 1 type Ia endoleak was treated intraoperatively. One (1.6%) aneurysm-related death occurred at 4 months due to a secondary aortoenteric fistula. Overall, endoleaks occurred in 3 (4.7%) patients (2 type Ia, 1 type II). The estimated rates for 18-month overall survival, freedom from aneurysm-related death, and freedom from secondary interventions were 92.7%, 98.4%, and 95.0%, respectively. Patients treated outside the IFU had a significantly higher incidence of device-related complications (p=0.03).

CONCLUSION

The use of the Nellix device in everyday clinical practice is safe and offers promising midterm results. The risk of secondary aortoenteric fistula requires further analysis. Longer follow-up is needed to assess the actual efficacy of the device, although the risk of migration with late endoleak seems low.

Global Experience With the Nellix Endosystem for Ruptured and Symptomatic Abdominal Aortic Aneurysms

Purpose: To assess the feasibility and safety of the endovascular aneurysm sealing (EVAS) technique in the treatment of acute abdominal aortic aneurysm (AAA). Methods: A retrospective, multicenter, observational study was conducted at 8 centers (7 European and 1 in New Zealand) experienced with EVAS in the elective setting. From February 2013 to April 2015, 58 patients (mean age 74±9 years; 46 men) with an acute AAA were treated (28 ruptured and 30 symptomatic). The primary endpoint of the study was 30-day mortality; secondary endpoints included endoleak, reinterventions, and 30-day morbidity. Results: The overall intensive care unit and hospital stays were 2.2±6.6 days and 9.7±11.4 days, respectively. Thirty-day mortality rates were 32% (9/28) for the ruptured group and 7% (2/30) for the symptomatic group, with morbidity rates of 57% and 17%, respectively. Early endoleak was present in only 2 (3%) patients, one in each group; both leaks were type Ia. Reinterventions within 30 days were performed in 8 patients in the ruptured group; in the symptomatic patients, the only perioperative reintervention was embolization a type Ia endoleak. The mean follow-up was 9.3±3.1 months in the ruptured group and 12.4±5.4 months in the symptomatic group. The mean aneurysm diameter at 30-day follow-up was 71.8±16.0 mm compared with 74.7±15.7 mm preoperatively in the ruptured group and 66.1±13.5 mm compared with 65.8±13.0 mm in the symptomatic group. Conclusion: EVAS in the acute setting appears safe and feasible and concordant with the literature for endovascular aneurysm repair. More robust prospective and comparative data are required to establish the position of the technique in the treatment algorithm of acute AAA.