Endovascular Aneurysm Sealing System Research Articles

Focused Update on Patients Treated with the Nellix EndoVascular Aneurysm Sealing (EVAS) System from the European Society for Vascular Surgery (ESVS) Abdominal Aortic Aneurysm Clinical Practice Guidelines

Focused Update on Patients Treated with the Nellix EndoVascular Aneurysm Sealing (EVAS) System from the European Society for Vascular Surgery (ESVS) Abdominal Aortic Aneurysm Clinical Practice Guidelines

Long-term evaluation of the EVAS system and management of the surgical complications

The Nellix system or EndoVascular Aneurysm Sealing (EVAS) showed poor long-term results, which led to the withdrawal of the device from the market. The objective of this study was to report the long-term results of EVAS as well as the surgical management of the associated complications.

Resultados de los tipos de endoprótesis en la reparación endovascular del aneurisma aórtico abdominal: experiencia a largo plazo de un centro colombiano de alta complejidad, el primer ejemplo latinoamericano

Introduction: Endovascular abdominal aortic aneurysm repair (EVAR) devices are associated with a higher rate of complications at 5-year follow-up. At least 30% of patients with EVAR devices require some type of reintervention (whether endovascular or open) at 10-year follow-up. These complications include endoleak, abdominal aortic aneurysms rupture, graft migration, occlusion or infection. The objective of this paper was to determine the rates of failure for each type of EVAR stent-graft used in our local population. Also, this paper is the first step to create a Colombian and Latin American transnational EVAR device registry. Material and method: Single-center retrospective observational cohort study. Thirty-four patients with abdominal aortic aneurysms (AAA) treated with EVAR were included from 2011 through 2017. Data were collected from the patients’ electronic medical records.Results: The stent-graft Endologicx Ba (Endologix, Irvine, CA, United States), Excluder (W.L. Gore, Newark, DE, United States), Zenith (Cook Medical, Bloomington, IN, United States), and Nellix endovascular aneurysm sealing system (EVAS) (Endologix, Santa Rosa, CA, United States) were not associated with any endoleaks or any type of complications after the EVAR procedure. The Aorfix (Lombard, Didcot, United Kingdom), and Endurant (Medtronic, Minneapolis, MN, United States) stent-grafts had rates of type II endoleak (in 1 and 2 patients) of 2.9% and 5.8%, respectively that closed spontaneously. No stent-graft developed type I, III or IV endoleaks or any endovascular or open reinterventions were needed. Conclusions: This study shows that the different types of stent-graft used for to treat AAA with EVAR can be used in a safe and feasible way with good postoperative clinical outcomes in the Latin American population.

Floating EVAS!

A 79 year old patient, unfit for open surgery, treated for a pararenal aortic aneurysm with the endovascular aneurysm sealing system (EVAS) with three chimneys in both renal arteries and the superior mesenteric artery, was lost to follow up and presented six years later with a type Ia endoleak and sac enlargement to 9 cm. (A) Computed tomography angiography reconstruction of the migrated left EVAS stent (red arrow). (B) The patient was successfully treated with a custom made thoraco-abdominal stent graft with three inner branches, an aorto-uni-iliac endoprosthesis on the right, plug on the left and femorofemoral crossover bypass.Image 1

Progressive Device Failure at Long Term Follow Up of the Nellix EndoVascular Aneurysm Sealing (EVAS) System

High rates of midterm failure of the Nellix EndoVascular Aneurysm Sealing (EVAS) System resulted in device withdrawal from the UK market. The study aim was to report long term Nellix EVAS outcomes and management of a failing device. A retrospective review of EVAS procedures at a tertiary unit was performed. Device failure was defined as a triad of stent migration, stent separation, and secondary sac expansion, or any intervention for type 1 endoleak, device rupture, or explant. 161 (male n=140, female n=21) patients with a median follow up of 6.0 (IQR 5.0-6.6) years were included. Freedom from all cause mortality estimate at six years was 41.5%. There were 70 (43.5%) device failures with a freedom from device failure estimate at six years of 32.3%. Failure was the result of sac expansion (n=41), caudal stent migration (n=36), stent separation (n=26), and secondary AAA rupture (n=15). A substantial number of type 1 endoleaks was present (1a n=33, 1b n=11), but the type 2 endoleak rate was low at 3.7%. Some 36 (22.4%) patients required re-intervention. Twenty-one patients underwent explant with no 30 day deaths. Six patients underwent Nellix-in-Nellix application (NINA) with one early death from bowel ischaemia and one patient who died later from non-aneurysm related cause. Two NINA patients have ongoing sac expansion and two have had thrombosis of a Nellix limb or visceral stent. Proximal embolisation was only successful in one of six cases. The long term failure rate of Nellix EVAS is high. All patients with a device must be informed and be enrolled in enhanced surveillance. EVAS explant is an acceptable technique with favourable outcomes. Management by open explant, if the patient is fit, should be considered early and offered to those with device failure.

Nellix endovascular aneurysm-sealing system: asingle-center experience and review of current evidence.

Aims: We report the 6-year results of our use of the Nellix® endovascular aneurysmsealing system. Materials & methods: This is a retrospective review of patients we treated from 2013 to 2019. The outcomes described include technical success rate, mortality, all procedure-related complications, reinterventions, open surgical conversion andsecondary sac rupture. Results & conclusions: A total of 68patients were treated. Mortality was 2.9%. Secondary interventions were carried out for distal embolization (3), stent occlusion (1), pseudoaneurysm (1) and endoleak (5). Open surgical conversion was required in 6.4% of cases. Medium-and long-term complications of EVAS occurred more frequently than expected. Because thedurability of endovascular aneurysm sealing is questionable, strict postoperative surveillance of Nellix is crucial to identify features of failure.

Incidence and Management of the Failing Nellix Endovascular Aneurysm Sealing System

High rates of midterm failure of the Nellix EndoVascular Aneurysm Sealing (EVAS) system (Endologix, Irvine, Calif) led the UK Medicines and Health Regulatory Authority to recommend explantation of all devices. The study aim was to report outcomes of reintervention and explantation for failing EVAS.

Three-Year Results of the Nellix Endovascular Aneurysm Sealing System for Treatment of Abdominal Aortic Aneurysms in Frail Patients with Poor Anatomical Features.

Endovascular aneurysm sealing represents an alternative to advanced technology devices for compromised patients with abdominal aortic aneurysms. We report our results of 15 fragile patients with very low-quality infrarenal necks treated with endovascular aneurysm sealing. All patients treated with Nellix device in our hospital between June 2015 and October 2016 were retrospectively reviewed. The primary endpoints are the following: overall survival and freedom from reintervention rates. The secondary endpoints are the following: technical success; 30-day mortality; abdominal aortic aneurysm-related mortality; and freedom from endoleak rate, complications, and surgical conversion rate. Nellix was used in 15 patients, median age 75.5 years, of which 67% were unfit for open surgery. Mean aneurysm diameter was 60 mm. One-third (5/15) of the patients were inside the Nellix instructions for use. Technical success rate was 93.3%. No perioperative complications existed, and 30-day mortality was 0%. Median follow-up was 35 (interquartile range: 11-37) months. Survival rates at 1 and 3 years were 80% and 59.3%. Abdominal aortic aneurysm-related mortality occurred in 3 of 15 cases. Freedom from rupture rates at 1 and 3 years were 92.9% and 66%. Freedom from endoleak rates at 1 and 3 years were 92.9% and 74.5%. Freedom from reintervention rates at 1 and 3 years were 86.7% and 70.6%, with a dramatic drop to 37.1% at 4 years of follow-up. Three open surgery conversions were needed. There were no statistically significant differences in results between patients treated inside and outside instructions for use. The endovascular aneurysm sealing has shown encouraging short-term results, but its safety and effectiveness during time is questionable, because this system still carries high rates of reintervention, conversions for type IA endoleaks, and secondary aneurysm ruptures.

Proper technical procedures improved outcomes in a retrospective analysis of EVAS FORWARD IDE trial 3-year results

ObjectiveAdverse outcomes observed late in the Nellix EndoVascular Aneurysm Sealing (EVAS) System (Endologix, Inc, Irvine, Calif) investigational device exemption trial prompted refinement of the anatomic instructions for use (IFU). This study aimed to investigate the association of procedural factors during Nellix endograft deployment and patient outcomes. MethodsWe retrospectively reviewed 1-month imaging of 333 patients enrolled in the prospective, multicenter EVAS investigational device exemption trial between January 2014 and September 2016. Initial observations of those patients who met revised anatomic IFU yet still experienced late adverse events suggested that inadequate seal and low graft placement were common among these patients. Key procedural variables identified from a univariate analysis were applied to construct four cohorts stratified by procedural technical performance (technically adequate [P+] or technically inadequate [P−]) and the revised anatomic indications for use (anatomically within IFU [A+] or anatomically outside of IFU [A−]) and to compare them for aneurysm-related outcomes. A logistic regression analysis was performed to identify significant predictors of sac expansion or migration. ResultsProximal and distal seal zones and low graft placement were identified by logistic regression analysis as significant predictors of sac expansion or migration. Accordingly, acquisition of ≥10-mm proximal and distal seal zones and the position of the lowest stent within 10 mm of the lowest renal artery were clinically justified as thresholds for a technically adequate procedure. Patients who did not achieve these parameters were deemed to have a technically inadequate procedure. By use of the proposed procedural adequacy criteria and established anatomic criteria, patients were stratified into four cohorts: A+/P+ (n = 77), A+/P− (n = 54), A−/P+ (n = 71), and A−/P− (n = 131). Three-year estimates of freedom from migration of 10 mm were 98.6% in A+/P+, 95.9% in A+/P−, 85.8% in A−/P+, and 80.1% in A−/P−; freedom from type IA endoleak estimates were 98.6% in A+/P+, 100% in A+/P−, 96.4% in A−/ P+, and 90.3% in A−/P− cohorts. Freedom from sac expansion and secondary intervention were 96.9% and 90.6% in A+/P+, 86.0% and 93.6% in A+/P−, 87.1% and 83.1% in A−/P+, and 80.5% and 79.8% in A−/P− groups, respectively. Two early deaths (aneurysm-related mortality) on days 4 and 12 postoperatively were reported within the A+/P− group. Kaplan-Meier estimates of freedom from all-cause mortality and aneurysm-related mortality at 3 years were similar between cohorts. ConclusionsThis post hoc analysis suggests that achieving a 10-mm proximal and distal seal with adequate positioning of the endograft with respect to the renal arteries is associated with improved patient outcomes.

Endovascular aneurysm sealing as an alternative for the treatment of failed endovascular aneurysm repair

Objective The Nellix EndoVascular Aneurysm Sealing (EVAS) system has offered a novel approach in the treatment of abdominal aortic aneurysm (AAA). While it is currently indicated as a primary procedure in patients with infrarenal AAA with suitable anatomy according to the indications for use, a few studies aimed to address its potential interest in failed endovascular aneurysm repair (EVAR). The aim of this systematic review was to analyze the postoperative outcomes of patients with prior EVAR who underwent EVAS. Design of the study A literature search was performed according to Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines in May 2019 and included patients with prior EVAR who underwent EVAS. The publications had to report at least one of the basic postoperative outcomes (technical success rate, all-cause complications, mortality, length of in-hospital stay, length of stay in intensive care unit, the need of re-intervention). Results Eleven studies fulfilled the inclusion criteria, for a total of 46 patients. EVAS was used to treat endoleaks in 45 cases (97.8%): 29 type Ia endoleaks (63%), 6 type IIIa endoleaks (13%), and 10 type IIIb endoleaks (21.7%). Standard EVAS procedure was performed in 21 patients (45.7%), and 25 patients (54.3%) had chimney-EVAS. The technical success was achieved in all the studies. Two patients (4.9%) died during the 30-day postoperative period, but no aneurysm-related mortality was reported. The presence of endoleaks was reported in five patients (9.8%) during the follow-up. Conclusion The results suggest the safety and the efficiency of EVAS in the treatment of complications following EVAR including type Ia, type IIIa, and type IIIb endoleaks. Further studies on larger cohorts and longer follow-up periods are required to confirm the interest of EVAS in the endovascular management of failed EVAR.

Endovascular Aneurysm Sealing (EVAS). Outcomes and Anatomical Suitability, a Single Centre Experience.

Introduction: EVAS has been introduced in 2013, since then the instructions for use (IFU) have changed in order to improve safety of the technique. The most significant changes were a maximum neck diameter reduction to 28mm and a ratio of maximum aortic aneurysm diameter to maximum aortic blood lumen <1,4. The aim of this study is firstly to assess the suitability of EVAS and to report our preliminary results of elective repair of abdominal aortic aneurysm (AAA) using the original IFU. Secondly we want to identify if the patients of our original cohort would have also been suitable for EVAS using the new IFU. Methods: We have investigated all patient treated with EVAS between June 2013 and December 2016. All patients undergoing elective AAA repair where eligible to enter the analysis. We have identified age, co-morbidity, aneurysm size, anatomical morphology, mortality and complications. Patients were followed until October 2017. Regular Follow up consists of routine computertomograpy angiogram and Doppler ultrasound. Of each included patient, we investigated if the aneurysm morphology would still make them suitable to undergo EVAS repair under the new IFU. Results: 61 patients (median age 77,5 years, range 56-90; 51 men) with an abdominal aortic aneurysm were treated with the Nellix EVAS system at our institution. The median aneurysm diameter was 60mm (range 53-82). Aneurysm morphology was compliant in 47 patients (77%) with the old IFU and 11 patients (18%) with the new IFU. The majority of cases 42 (69%) were not suitable because of a high ratio between thrombus and flow lumen (≥ 1,4). Patients were followed up until the first October 2017 or date of death. Median follow up was 33 months. In follow up we identified 13 (21%) type 1A endoleaks of which 5 patients were inside the new IFU, 4 (7%) ruptures, and 4 (7%) limb occlusions. Overall mortality was 18% of which 10% (6 patients) was aneurysm related and 7% (4 patients) died of unknown cause. Conclusion: In conclusion EVAS with the new IFU for the management of AAA is only suitable for a small percentage of our patients and in our cohort there was a high mortality rate and incidence of Type 1a endoleaks.

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

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. 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>2.0mg/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. 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 5.5cm(Pfor 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). 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.

Anatomical Predictors of Endoleaks or Migration After Endovascular Aneurysm Sealing

Purpose: To identify preoperative anatomical aortic characteristics that predict seal failures after endovascular aneurysm sealing (EVAS) and compare the incidence of events experienced by patients treated within vs outside the instructions for use (IFU). Methods: Of 355 patients treated with the Nellix EndoVascular Aneurysm Sealing System (generation 3SQ+) at 3 high-volume centers from March 2013 to December 2015, 94 patients were excluded, leaving 261 patients (mean age 76±8 years; 229 men) for regression analysis. Of these, 83 (31.8%) suffered one or more of the following events: distal migration ⩾5 mm of one or both stent frames, any endoleak, and/or aneurysm growth >5 mm. Anatomical characteristics were determined on preoperative computed tomography (CT) scans. Patients were divided into 3 groups: treated within the original IFU (n=166), outside the original IFU (n=95), and within the 2016 revised IFU (n=46). Categorical data are presented as the median (interquartile range Q1, Q3). Results: Neck diameter was significantly larger in the any-event cohort vs the control cohort [23.7 mm (21.7, 26.3) vs 23.0 mm (20.9, 25.2) mm, p=0.022]. Neck length was significantly shorter in the any-event cohort [15.0 mm (10.0, 22.5) vs 19.0 mm (10.0, 21.8), p=0.006]. Maximum abdominal aortic aneurysm (AAA) diameter and the ratio between the maximum AAA diameter and lumen diameter in the any-event group were significantly larger than the control group (p=0.041 and p=0.002, respectively). Regression analysis showed aortic neck diameter (p=0.006), neck length (p=0.001), and the diameter ratio (p=0.011) as significant predictors of any event. In the comparison of events to IFU status, 52 (31.3%) of 166 patients in the inside the original IFU group suffered an event compared to 13 (28.3%) of 46 patients inside the 2016 IFU group (p=0.690). Conclusion: Large neck diameter, short aortic neck length, and the ratio between the maximum AAA and lumen diameters are preoperative anatomical predictors of the occurrence of migration (⩾5 mm), any endoleak, and/or aneurysm growth (>5 mm) after EVAS. Even under the refined 2016 IFU, more than a quarter of patients suffered from an event. Improvements in the device seem to be necessary before this technique can be implemented on a large scale in endovascular AAA repair.

Effects on Aortoiliac Fluid Dynamics After Endovascular Sealing of Abdominal Aneurysms.

To evaluate the effects on aortoiliac fluid dynamics after the implantation of an endograft based on endovascular aneurysm sealing (EVAS) versus endovascular aneurysm repair (EVAR) strategy. An adaptive geometrical deformable model was used for aortic lumen segmentation in 8 patients before and after the surgery. Abdominal aneurysms were treated with an endograft based on the EVAS system (Nellix, n = 4) and with a device based on an anatomical fixation technology (n = 4). Pressure, blood velocity, and wall shear stress (WSS) were estimated at different aortic regions using computational fluid dynamics methods. Physiologic inlet/outlet flow values at the abdominal aorta, the celiac trunk, and the mesenteric and the renal arteries were set. Pressure references were set at iliac arteries outlet. Maximum aneurysm sizes were similar for both groups in the preoperative scans. The lumen area was lower after EVAR ( P < .05) and EVAS ( P < .01) compared to preoperative aortic lumen sizes. Pressure increase was higher in the proximal abdominal aorta after EVAS compared to EVAR (2.3 ± 0.3 mm Hg vs 0.9 ± 0.3 mm Hg, P < .001). Peak blood velocities inside the endografts were 3-fold higher for EVAS compared to EVAR (54 ± 5 cm/s vs 17 ± 4 cm/s, P < .01). Velocities at the iliac arteries also remained higher for EVAS (38 ± 4 cm/s vs 24 ± 4 cm/s, P < .05). Peak WSS at the iliac arteries remained higher for EVAS compared to EVAR group ( P < .05). The significant modification of the aortic bifurcation anatomy after EVAS alters aortoiliac fluid dynamics, showing a pressure impact at the renal arteries level and an acceleration of the blood velocity at the iliac region with a concomitant increase in peak WSS.

Apposition and Positioning of the Nellix EndoVascular Aneurysm Sealing System in the Infrarenal Aortic Neck

Purpose: To investigate the initial proximal position and seal of the Nellix EndoVascular Aneurysm Sealing (EVAS) system in the aortic neck using a novel methodology. Methods: Forty-six consecutive patients who underwent elective EVAS for an abdominal aortic aneurysm were retrospectively selected and dichotomized into an early (n=23) and a late (n=23) group. The aortic neck morphology and aortic neck surface (ANS) were determined on preoperative computed tomography (CT) scans; the endograft position and nonapposition surface (NAS) were determined on the 1-month CT scans. The position of the proximal endobag boundary was measured by 2 experienced observers to analyze the interobserver variability for the EVAS NAS measurements. The shortest distance from the lowest renal artery to the endobag (shortest fabric distance) and the shortest distance from the endobag to the end of the infrarenal neck (shortest sealing distance) were determined. The intraclass correlation coefficients (ICCs) are presented with the 95% confidence interval (CI). Continuous data are presented as the median and interquartile range (IQR: Q3 – Q1). Results: There were no differences between the early and late EVAS groups regarding aortic neck morphology except for the neck calcification circumference [41° (IQR 33°) vs 87° (IQR 60°), respectively; p=0.043]. Perfect agreement was observed for the NAS (ICC 0.897, 95% CI 0.780 to 0.956). The NAS as a percentage of the preoperative ANS was 47% (IQR 43) vs 49% (IQR 49) for the early vs late groups, respectively (p=0.214). The shortest fabric distances were 5 mm (IQR 5) and 4 mm (IQR 7) for the early and late groups, respectively (p=0.604); the shortest sealing distances were 9 mm (IQR 13) and 16 mm (IQR 17), respectively (p=0.066). Conclusion: Accurate positioning of the Nellix EVAS system in the aortic neck may be challenging. Despite considerable experience with the system, still around half of the potential seal in the aortic neck was missed in the current series, without improvement over time. This should be considered during preoperative planning and may be a cause of a higher than expected complication rate. Detailed post-EVAS nonapposition surface can be determined with the described novel methodology that takes into account the sometimes irregularly shaped top of the sealing endobags.

Two-Year Outcomes of the Nellix EndoVascular Aneurysm Sealing System for Treatment of Abdominal Aortic Aneurysms

Purpose: To analyze the 2-year outcomes of endovascular aneurysm sealing (EVAS) according to 2 versions of the instructions for use (IFU). Methods: A retrospective study was conducted involving 355 consecutive patients treated with the first-generation EVAS device from April 2013 to December 31, 2015, at 3 high-volume centers. Out of 355 patients treated with EVAS, 264 were elective asymptomatic infrarenal EVAS procedures suitable for analysis. In this cohort, 168 (63.3%) patients were treated within the IFU 2013 criteria; of these 48 (18.2%) were in compliance with the revised IFU 2016 version. Results: Overall technical success was 98.2% (165/168) in the IFU 2013 group and 97.9% (47/48) in the IFU 2016 subgroup (p=0.428). The 2-year freedom from reintervention estimates were 89.7% (IFU 2013) and 95.7% (IFU 2016), with significantly more reinterventions in the first 45 cases (p=0.005). The stenosis/occlusion estimates were 6.5% (IFU 2013) and 4.2% (IFU 2016; p=0.705). Nine (5.4%) endoleaks (8 type Ia and 1 type Ib) were observed within the IFU 2013 cohort; 3 (2.1%) were in the IFU 2016 subgroup (p=0.583). Migration ≥10 mm or ≥5 mm requiring intervention was reported in 12 (7.1%) patients in the IFU 2013 cohort but none within the IFU 2016 subgroup. Ten (6.0%) patients demonstrated aneurysm growth in the IFU 2013 cohort, of which 2 (4.2%) were in the IFU 2016 subgroup. Overall survival and freedom from aneurysm-related death estimates at 2 years were 90.9% and 97.6% in the IFU 2013 cohort (IFU 2016: 95.5% and 100.0%). The prevalence of complications seemed lower within IFU 2016 without significant differences. Conclusion: This study shows acceptable 2-year results of EVAS used within the IFU, without significant differences between the 2 IFU versions, though longer follow-up is indicated. The refined IFU significantly reduced the applicability of the technique.

Greater Compliance within Instruction for Use for Concomitant Iliac Aneurysms and Adverse Aneurysm Characteristics–Initial Experience with the Nellix Endovascular Aneurysm Sealing System at a Single Institution

The Nellix was introduced to Asia in 2014. Data in Asians have been sparse. Twoballoon-expandable stents, each surrounded by a polymer-filled endobag, are deployed in parallel to obliterate and seal the aneurysm. This paradigm shift to treating abdominal aortic aneurysms confers advantages for certain adverse aneurysm morphology that is outside the instruction-for-use (IFU) for standard endovascular aneurysm repair (EVAR) devices. We examine outcomes of 15 Asian patients with concomitant infrarenal aortic and iliac artery aneurysms treated with the Nellix at our institution. Between July 2014 and August 2016, 15 male patients underwent elective EVAS at a single tertiary center by the same team of vascular surgeons and interventional radiologists. Patient demographics, clinical presentations, aneurysm morphology, perioperative complications, and follow-up imaging according to the standardized protocol were studied. Preoperative CT images were analyzed using validated automatic 3-dimensional sizing software EndoSize. The novel stent-graft deployment proves consistent and achieved a 100% technical success. Eleven patients (70%) complied within specified Nellix IFU, as compared to 20% if standard endovascular aneurysm repair (EVAR) IFU was applied. The difference is due to the presence of concurrent common iliac aneurysms (n=5), short neck length (n=3), and angulated necks (n=3). Adjunct procedures included 3 open access endarterectomy with embolectomy, 1 coil embolization of internal iliac artery, 1 bilateral renal artery chimneys, and 1 proximal stent deployment. There was no conversion to open surgery. Average operative time was 133min. Median length of stay was 4days. Thirty-day mortality was 0%. Perioperative morbidity included exacerbation of pre-existing renal impairment (n=6), peripheral vascular disease (n=3), and postimplantation syndrome (n=5). One endoleak (7%) and 2 instances of stent migration (14%) were detected. There was no complication of aneurysm or endobag rupture, limb thromboses, or fracture. Early data in our center are encouraging and highlight high procedural success with minimal complications despite challenging patient anatomy.

Editor's Choice – Occurrence and Classification of Proximal Type I Endoleaks After EndoVascular Aneurysm Sealing Using the Nellix™ Device

Proximal type I endoleaks are associated with abdominal aortic aneurysm (AAA) growth and rupture and necessitate repair. The Nellix™ EndoVascular Aneurysm Sealing (EVAS) system is a unique approach to AAA repair, where the appearance and treatment of endoleaks is also different. This study aimed to analyse and categorise proximal endoleaks in an EVAS treated cohort. All patients, treated from February 2013 to December 2015, in 15 experienced EVAS centres, presenting with proximal endoleak were included. Computed tomography scans were analysed by a core laboratory. A consensus meeting was organised to discuss and qualify each case for selection, technical aspects, and possible causes of the endoleak. Endoleaks were classified using a novel classification system for EVAS. During the study period 1851 patients were treated using EVAS at 15 centres and followed for a median of 494±283 days. Among these, 58 cases (3.1%) developed a proximal endoleak (1.5% early and 1.7% late); of these, 84% of 58 patients were treated outside the original and 96% outside the current, refined, instructions for use. Low stent positioning was the most likely cause in 44.6%, a hostile anatomy in 16.1%, and a combination of both in 33.9%. Treatment, by embolisation or proximal extension, was performed in 47% of cases, with a technical success of 97%. The overall incidence of proximal endoleak after EVAS is 3.1% after a mean follow-up period of 16 months, with 1.5% occurring within 30 days. Their occurrence is related to patient selection and stent positioning. Early detection and classification is crucial to avoid the potential of sac rupture.

IP097. EVAR With Contemporary Volume-Dependent Sac Embolization Compared to Endovascular Aneurysm Sealing System (EVAS) in the Prevention of Type II Endoleak and Its Complications

IP097. EVAR With Contemporary Volume-Dependent Sac Embolization Compared to Endovascular Aneurysm Sealing System (EVAS) in the Prevention of Type II Endoleak and Its Complications

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

ObjectiveThe 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. MethodsEligible 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. ResultsOf 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. ConclusionsOutcomes 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.