Article Text

Original research
Aneurysm treatment with the Woven EndoBridge (WEB) device in the combined population of two prospective, multicenter series: 5-year follow-up
  1. Laurent Pierot1,
  2. Istvan Szikora2,
  3. Xavier Barreau3,
  4. Markus Holtmannspoetter4,
  5. Laurent Spelle5,6,
  6. Joachim Klisch7,
  7. Denis Herbreteau8,
  8. Vincent Costalat9,
  9. Jens Fiehler10,
  10. Anne-Christine Januel11,
  11. Thomas Liebig12,
  12. Luc Stockx13,
  13. Werner Weber14,
  14. Joachim Berkefeld15,
  15. Jacques Moret5,
  16. Andy Molyneux16,
  17. James Byrne17
  1. 1Department of Neuroradiology, CHU Reims, Reims, Champagne-Ardenne, France
  2. 2Neurointerventions, National Institute of Clinical Neurosciences, Budapest, Hungary
  3. 3Neuroradiology Department, CHU Bordeaux GH Pellegrin, Bordeaux, Aquitaine, France
  4. 4Interventional and Diagnostic Neuroradiology, Nuremberg Hospital Campus South, Nurnberg, Germany
  5. 5NEURI Interventional Neuroradiology, APHP, Paris, Île-de-France, France
  6. 6Neuroradiology, Paris-Saclay University Faculty of Medicine, Le Kremlin-Bicetre, France
  7. 7Neuroradiology, Helios Klinikum Erfurt, Erfurt, Thüringen, Germany
  8. 8NRI, CHU Tours, Tours, France
  9. 9Neuroradiology, CHU Montpellier, Montpellier, Languedoc-Roussillon, France
  10. 10Department of Neuroradiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
  11. 11Neuroradiology, CHU Toulouse, Toulouse, Occitanie, France
  12. 12Department of Neuroradiology, University Hospital Munich, Munchen, Bayern, Germany
  13. 13Neuroradiology, Ziekenhuis Oost-Limburg, Genk, Limburg, Belgium
  14. 14Radiology and Neuroradiology, Ruhr-Universität Bochum, Bochum, Nordrhein-Westfalen, Germany
  15. 15Institute of Neuroradiology, Goethe-Universitat Frankfurt am Main, Frankfurt am Main, Hessen, Germany
  16. 16Neurovascular and Neuroradiology Research Unit, Oxford University, Oxford, UK
  17. 17Department of Neuroradiology, Oxford University, Oxford, UK
  1. Correspondence to Dr Laurent Pierot, Department of Neuroradiology, CHU Reims, Reims, Champagne-Ardenne, France; lpierot{at}gmail.com

Abstract

Background Evaluating a new endovascular treatment for intracranial aneurysms must not only demonstrate short-term safety and efficacy, but also evaluate longer-term outcomes (eg, delayed complications, anatomical results, retreatment). The current analysis reports the 5-year clinical and anatomical results of Woven EndoBridge (WEB) treatment in two European combined trial populations (WEBCAST (WEB Clinical Assessment of Intrasaccular Aneurysm Therapy) and WEBCAST-2).

Methods All adverse events occurring between the procedure and 5-year follow-up were independently evaluated by an expert. Aneurysm occlusion was evaluated by an independent core laboratory using a three-grade scale: complete occlusion, neck remnant, and aneurysm remnant. In cases where data were not available at 5-year follow-up, the last observation carry forward (LOCF) method was used.

Results The safety and efficacy populations comprised 100 patients and 95 aneurysms, respectively. No adverse event related to the device occurred after the procedure during the 5-year follow-up period. Mortality at 5 years was 7.0% (7/100 patients) including mortality related to the WEB (0/100, 0.0%), the procedure (1/100, 1.0%), and another condition (6/100, 6.0%). At 5 years, complete aneurysm occlusion was observed in 49/95 (51.6%) aneurysms, neck remnant in 25/95 (26.3%), and aneurysm remnant in 21/95 (22.1%). Retreatment rate at 5 years was 11.6% (11/95 aneurysms).

Conclusions This analysis conducted in a population of patients with wide-neck bifurcation aneurysms confirms WEB’s safety profile. Additional evidence demonstrates good stability of aneurysm occlusion with adequate occlusion (complete occlusion or neck remnant) at 5 years in 77.9% of aneurysms with a low retreatment rate (11.6%).

Clinical trial registration WEBCAST and WEBCAST-2: Unique identifier: NCT01778322.

  • Aneurysm

Data availability statement

Data are available upon reasonable request.

http://creativecommons.org/licenses/by-nc/4.0/

This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.

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WHAT IS ALREADY KNOWN ON THIS TOPIC

  • Studies (including WEBCAST, WEBCAST-2, and French Observatory) have shown the great safety and good efficacy of wide-neck bifurcation aneurysm treatment with the WEB device at mid- and long-term follow-up (1, 2 and 3 years).

  • The importance of studying complications and occlusion stability at very long term for complex aneurysms.

WHAT THIS STUDY ADDS

  • 5-year analysis in WEBCAST and WEBCAST-2 confirms the high safety of WEB aneurysm treatment with no adverse event related to the device occurring after the procedure during the 5-year follow-up period.

  • This analysis also shows good stability of aneurysm occlusion at 5-year with a low retreatment rate.

HOW THIS STUDY MIGHT AFFECT RESEARCH, PRACTICE OR POLICY

  • This analysis confirms the high safety and good efficacy of WEB aneurysm treatment at very long-term follow-up, which might induce further adoption in real life practice.

Introduction

Evaluating an intracranial aneurysm (IA) treatment must determine its safety and efficacy in the short-, mid-, and long-term. The experience we have with flow diversion shows that complications such as remote hematomas or parent artery thrombosis can occur several months after the initial treatment.1–3 Aneurysm recanalization is a well-known phenomenon after aneurysm coiling: it can be associated with aneurysm bleeding or rebleeding, and can occur and worsen several months or years after the initial tratment.4 Therefore, short- and mid-term evaluations alone cannot precisely evaluate the results of a new aneurysm treatment: instead, long-term evaluation is mandatory to draw evidence-based conclusions about treatment efficacy.

Treatment of wide-neck aneurysms and, more specifically, wide-neck bifurcation aneurysms (WNBA), is technically difficult and has led to the development of new techniques such as balloon-assisted coiling (BAC), stent-assisted coiling (SAC), flow diversion, and intrasaccular flow disruption.5 Currently, only one flow disrupter has been widely clinically evaluated: the Woven EndoBridge (WEB) device (Microvention, Aliso Viejo, California, USA). Since its introduction into clinical practice in Europe in 2010, the device’s design has significantly evolved from the initial dual layer (DL) version (WEB-DL) to the single layer (SL) versions (WEB-SL and WEB-SLS (single layer spherical)). The device evolution improved with the integration of DFT (drawn filled tubing) wires made from nitinol and platinum, which heightened visibility and led to EV (enhanced visualization) device versions. Additionally, the delivery microcatheter has also evolved, with the development of microcatheters dedicated to WEB device placement: VIA microcatheters (Microvention).

Since WEB’s introduction, this treatment has been extensively evaluated in several Good Clinical Practice (GCP) studies conducted in Europe (WEB Clinical Assessment of Intrasaccular Aneurysm Therapy (WEBCAST) and WEBCAST-2); in the United States (WEB Intrasaccular Therapy (WEB-IT)); and in France (French Observatory).5–11 Additional WEB trials have recently been published (CLinical Assessment of WEB Device in Ruptured aneurYSms (CLARYS)), are under analysis (CLinical EValuation of WEB 0.017 Device in Intracranial AneuRysms (CLEVER)), or are currently recruiting (WEB-IT China).12

The present study analyzes the clinical outcomes and anatomical results at 5 years of WEB aneurysm treatment in the combined WEBCAST and WEBCAST-2 trial populations.

Methods

The article has been prepared in accordance with the STROBE statement.

WEBCAST and WEBCAST-2 are prospective, consecutive, multicenter, single-arm European trials dedicated to evaluating WEB treatment for WNBA. Both trials received national regulatory authorization according to each country’s regulations. In France, the study was approved by the Consultative Committee of Information Processing in Healthcare Research Program (CCTIRS), the Reims Institutional Review Board, and the National Commission for Data Processing and Freedom (CNIL). In Germany, the study was approved by local ethics committees of participating centers. Written informed consent was obtained from all patients. Enrollment took place from December 2011 to February 2014 for WEBCAST and from July 2014 to May 2015 for WEBCAST-2.

WEB devices

The WEB is a self-expanding, retrievable, electrothermally detachable, braided device, which is placed within the aneurysm sac. During the study time frame, the device existed in several iterations (see Introduction). In WEBCAST, patients were treated with WEB-DL, while WEBCAST-2 patients were treated with WEB-SL-EV and WEB-SLS-EV. The WEB device exists in different sizes as defined by their width and height.

In tandem with device developments, the microcatheters used to deliver these devices also evolved with the development of microcatheters dedicated to WEB treatment: VIA microcatheters (Microvention) now exist in different sizes according to the WEB size, which will be placed in the aneurysm sac (VIA 17, VIA 21, VIA 27, and VIA 33).

Trial design and procedural modalities

Trial design and procedural modalities have been described in previous publications, and both studies were conducted following GCP guidelines.5–10 Inclusion criteria for the two studies were: ruptured (Hunt and Hess I to III) and unruptured aneurysms located in the basilar artery (BA) apex, middle cerebral artery (MCA) bifurcation, internal carotid artery terminus (ICAt), or anterior communicating artery complex (Acom).

A local multidisciplinary team (neurosurgeons and neuroradiologists) selected participants with aneurysms treated by endovascular treatment. Selection of aneurysms treated with the WEB device was performed autonomously in each center by interventional neuroradiologists based on aneurysm characteristics.

Data collection

Each center completed a patient file with the following data:

  • Demographics: age and sex;

  • Aneurysm: rupture status, location, aneurysm size (width and height), and neck size; and

  • Procedure: date, device type used (DL or SL/SLS), and complications occurring during or after procedure.

Preoperative Hunt and Hess grade was collected with ruptured aneurysms. Modified Rankin Scale (mRS) score was gathered before treatment for unruptured aneurysms. In addition to clinical follow-up at 30 days (±7 days), clinical and imaging follow-up was expected at 6 months, 1, 3, and 5 years. For patients without vascular imaging follow-up at 5 years, the reason for not performing this examination was collected. Before considering the patient as being lost to follow-up, at least three attempts to contact the patient and/or the general physician were done.

Data analysis

All adverse events were independently and blindly monitored and analyzed by a single medical monitor (AM), including events that occurred after retreatment if any. Morbidity was defined by mRS greater than 2, evaluated by a neurosurgeon, a neurologist, or a neuroradiologist not involved in the patient’s treatment. Aneurysm occlusion was evaluated by an independent expert interventional neuroradiologist (JVB) using a three-grade scale: complete occlusion, neck remnant, and aneurysm remnant. This evaluation was performed on postoperative digital subtraction angiography (DSA), and at each yearly follow-up between 1-year and 5-year vascular imaging (DSA, magnetic resonance angiography (MRA), or computed tomography angiography (CTA)), which was selected autonomously by the centers. Based on previous work, opacification of the WEB device’s proximal recess was considered complete occlusion.13 Aneurysm occlusion and its evolution between 1 and 5 years were also evaluated in the subgroup of patients having a 5-year follow-up. Evolution of aneurysm occlusion was made using a threegrade scale: worse, stable, and improved. Worsening and improvement were defined as a grade change in the three-grade occlusion scale.

Per protocol, patients in whom a WEB was intended but not placed (not deployed or not implanted) were included in the safety analysis up to 30-day follow-up and they were excluded afterwards. For patients who were retreated after the initial WEB procedure, the follow-up for aneurysm occlusion was not collected after the time of retreatment as the goal of WEBCAST/WEBCAST-2 was to evaluate the efficacy (aneurysm occlusion) after WEB treatment alone. The last evaluation used for these patients was the occlusion evaluation before retreatment.

An analysis based on last observation carry forward (LOCF) method was used for the results at 5 years, to replace any data not available with the last data available.

Statistical analysis

Continuous variables were described as mean±SD. Categorical data were described numerically as a categorical total and as a percentage of the analyzed population. Binomial data were described as a ratio of the true value and the analyzed population (x/n). Confidence intervals for binomial data were calculated by the Clopper-Pearson method, and P values were calculated by Fisher's exact test. Analyses were conducted using SPSS statistical software (SPSS, Chicago, Illinois, USA).

Results

Patient and aneurysm population

The two trials combined population initially included 106 patients. After removing patients having withdrawn consent (6), 100/106 patients (94.3%) potentially had 5 years follow-up. According to the study flow chart (figure 1), this safety group comprised 100/106 patients (94.3%), including 68 females (68.0%), with an age range of 27–77 years (mean: 54.6±10.5 years). The mean for safety follow-up was 50.4±20.7 months after initial procedure.

Figure 1

Population flow chart for the two studies for safety and efficacy at 5 years. ‘Lost to follow-up’ means that the centers were unable to contact the patients using different techniques (telephone call, email, letter, etc.) so the patient exited the study.

After excluding patients for whom WEB efficacy could not be evaluated (no WEB implanted (5), consent withdrawn (6)), the percentage of aneurysms with 5 years anatomical follow-up was 89.6% (95/106 aneurysms) (figure 1). The mean for efficacy follow-up was 53.0±17.7 months after initial procedure. Aneurysm status was ruptured in 7/95 (7.4%) and unruptured in 88/95 (92.6%) patients. Aneurysm locations per core laboratory analysis were MCA in 49/95 aneurysms (51.6%), Acom in 20/95 (21.1%), BA in 17/95 (17.9%), and ICAt in 9/95 (9.5%). Maximum aneurysm size ranged from 2.8 to 17.0 mm (mean: 7.3±2.6 mm). The neck was wide (≥4 mm) in 79/95 (83.2%) aneurysms.

Mortality and morbidity at 5 years

Mortality at 5 years in patients treated exclusively with WEB was reported in 7/100 patients (7.0%). There were no deaths during the procedure and in the month following the initial procedure, three deaths between 1 month and 1 year (3.0%), one death between 1 year and 2 years (1.0%), two deaths between 2 and 3 years (2.0%), and one death between 3 and 4 years (1.0%). No deaths occurred between 4 years and 5 years. Of the seven deaths, 1 (1.0%) occurred 74 days after the initial WEB treatment and was related to the initial procedure (retroperitoneal hematoma) not the device. Four deaths were unrelated to the initial procedure (skin cancer at 126 days, lung cancer at 166 days and 743 days, and pneumonia at 780 days). Two deaths occurred after the retreatment of the aneurysm (see later) but were unrelated to the initial procedure and retreatment (pulmonary cancer at 840 days of the initial WEB procedure and respiratory failure at 1219 days).

At 5 years, 1/100 (1.0%) patients had morbidity unrelated to the initial procedure (alcoholic neuropathy) that occurred more than 2 years after the initial procedure. Finally, mortality and morbidity related to the WEB were 0.0% and 0.0% at 5 years, respectively, while procedure-related mortality and morbidity were 1.0% and 0.0%, respectively.

Anatomical results at 5 years

Five-year follow-up was analyzed in 95 patients/aneurysms including 11 who were retreated (see table 1). Some 46/95 (48.4%) patients had no follow-up at 5 years and their last follow-up performed was taken into account according to the LOCF methodology and were as follows: 4 (4.2%) at the index procedure, 2 (2.1%) at 6 months, 14 (14.7%) at 1 year, 6 (6.3%) at 2 years, 10 (10.5%) at 3 years, and 10 (10.5%) at 4 years. Vascular imaging techniques included DSA in 27/95 aneurysms (28.4%), MRA in 51/95 (53.7%) aneurysms, CTA in 8/95 (8.4%) aneurysms, and type of images not specified in 9/95 (9.5%) aneurysms. At 5 years, complete occlusion was observed in 49/95 (51.6%) aneurysms, neck remnant in 25/95 (26.3%), and aneurysm remnant in 21/95 (22.1%). Adequate occlusion (complete occlusion or neck remnant) was observed in 74/95 (77.9%) aneurysms. Importantly, no neck or aneurysm remnant was associated with bleeding/rebleeding during the follow-up period.

Table 1

Aneurysm occlusion at 5 years in aneurysms treated with Woven EndoBridge dual layer (WEB-DL) and Woven EndoBridge single layer/single layer spherical (WEB-SL/SLS)

Excluding 46 patients not having a follow-up at 5 years with images to evaluate the occlusion (lost to follow-up (8), follow-up without images (22), deaths (7), retreatment (9)), 49 patients had a 5-year follow-up (mean: 60.0±3.2 months). Complete occlusion was observed in 28/49 (57.1%) aneurysms, neck remnant in 15/49 (30.6%), and aneurysm remnant in 6/49 (12.2%). Adequate occlusion was observed in 43/49 (87.8%) aneurysms. Compared with 1-year aneurysm occlusion, occlusion at 5 years was improved in 7/49 (14.3%) aneurysms, stable in 36/49 (73.5%), and worsened in 6/49 (12.2%). Worsening of aneurysm occlusion evolved from complete occlusion to neck remnant in 5/49 (10.2%) aneurysms, complete occlusion to aneurysm remnant in 0/49 (0.0%) aneurysm, and neck remnant to aneurysm remnant in 1/49 (2.0%) aneurysm.

Anatomical results at 5 years in aneurysms treated with WEB-DL and WEB-SL/SLS

No significant differences were observed in anatomical results for aneurysms treated with WEB-DL and WEB-SL/SLS (table 1).

Anatomical results at 5 years in different aneurysm locations

No significant differences were observed in anatomical results based on aneurysm location (table 2).

Table 2

Aneurysm occlusion at 5 years according to aneurysm location

Retreatment

Retreatment rate was evaluated in 95 aneurysms. Five aneurysms untreated with WEB (one protrusion, one subsequent retrieval of device, three lack of appropriate device sizing) and six patients who withdrew consent were excluded from this analysis.

The retreatment rate at 5 years was 11.6% (11/95 aneurysms). Retreatment rate was statistically not different when the device used in the index procedure was WEB-DL in 4/44 (9.1%) compared with WEB-SL/SLS in 7/51 (13.7%) (P=0.537). Retreated aneurysm locations per core laboratory analysis were MCA in 6/49 aneurysms (12.2%), Acom in 2/20 (10.0%), BA in 3/17 (17.6%), and ICAt in 0/9 (0%) (P=0.750). Retreatment was mainly performed during the first 2 years post-treatment: 3 (3.2%) between index procedure and 1 year, 5 (5.3%) between 1 and 2 years, 0 (0.0%) between 2 and 3 years, 2 (2.1%) between 3 and 4 years, and 1 (1.1%) between 4 and 5 years. Aneurysm occlusion status at retreatment time was neck remnant in 2 (2.1%) aneurysms and aneurysm remnant in 9 (9.5%) aneurysms. Retreatment modalities were stent (with coils: 3, with WEB: 2, without coils or WEB: 1) in 6 (6.3%), WEB alone in 1 (1.1%) aneurysm, clipping in 2 (2.1%) aneurysms (clipping failed in one case), and flow diverter in 2 (2.1%) aneurysms.

Discussion

This analysis reports the combined population of two European GCP WEB trials (WEBCAST, WEBCAST-2) at 5-year follow-up. This long-term analysis confirms the high safety of WEB aneurysm treatment. Mortality at 5 years was 7.0%, including 0.0% mortality related to the WEB device, 1.0% related to the initial procedure, and 6.0% related to other diseases (mostly cancer and infection). Morbidity at 5 years was 1.0% unrelated to WEB or initial procedure (alcoholic neuropathy). Complete occlusion was observed in 51.6%, neck remnant in 26.3%, and aneurysm remnant in 22.1% with adequate occlusion in 77.9%. Finally, retreatment was performed in 11.6% of cases at 5 years.

The value of long-term follow-up is to determine whether a given treatment is associated with delayed complications and if aneurysm occlusion is stable or unstable. In our series, no delayed adverse events were reported after 1 year, in contrast to what has been observed with flow diversion.1–3 14 The current analysis confirms the very high safety of WEB aneurysm treatment. Morbidity and mortality at 5 years (1.0% and 7.0%, respectively) were mostly due to unrelated diseases (alcoholic neuropathy for morbidity, cancer and infection for mortality). No morbidity or mortality at 5 years was related to the WEB device. At 5 years, mortality related to the initial procedure was low (1.0% induced by a retroperitoneal hematoma related to femoral puncture) and morbidity related to the initial procedure was 0.0%. Comparing long-term safety of WEB aneurysm treatment with other endovascular approaches is not an easy task given that very few studies report follow-up beyond 1 year, and the global mortality is not exclusively related to the aneurysm or its treatment, but can be due to unrelated conditions. This unrelated mortality is different from one series to another depending on several patient factors such as age, sex, risk factors, and associated diseases. Furthermore, the longer the follow-up, the greater the chance of outcomes from unrelated conditions (cancer, infection, etc.).

Regarding coiling, the Matrix and Platinum Science (MAPS) trial reported a 5-year follow-up showing 49 deaths in 477 followed-up patients (10.3%).15 In a large meta-analysis that included 14 634 aneurysms treated by coiling, all-cause mortality was 2.8% at 5 years and 4.3% at 7 years.16 In these two series, causes of death were not reported, which makes comparison with our series difficult. Regarding flow diversion, 3.7% (4.6% if patients with no 5-year follow-up are excluded) 5-year mortality is reported in the Pipeline for Uncoilable or Failed Aneurysms (PUFS) trial with no details regarding cause of death.16

Evaluation of long-term stability of aneurysm occlusion is the main reason for having long-term follow-up when evaluating a new endovascular treatment for IAs. Coiled aneurysms often reopen after coiling. In the recent ARETA publication dealing with 908 patients harboring 945 aneurysms treated by coiling (including BAC), the rate of aneurysm recanalization at 1 year was 29.5%.17 If recanalization often occurs in the first year post-procedure, it can also be encountered after 1 year or the remnant can continue to grow after 1 year. Thus, it is not only important to assess stability of aneurysm occlusion at mid-term but also in the long term. In the combined WEBCAST and WEBCAST-2 population, anatomical results were also analyzed at 3 years, showing complete aneurysm occlusion in 50.8%, neck remnant in 32.8%, and aneurysm remnant in 16.4% with adequate occlusion (complete occlusion and neck remnant) in 83.6%.18 These results are quite similar to what is reported at 5 years, demonstrating the stability of aneurysm treatment with WEB. Occlusion stability obtained with WEB treatment is also confirmed by the evolution between 1 year and 5 years post-procedure, analyzed in the subgroup of patients with 5-year follow-up. Aneurysm occlusion was stable and improved in 43/49 aneurysms (87.8%) and worsened in 6/49 (12.2%). Moreover, worsening occurred in the vast majority of aneurysm evolution from complete occlusion to neck remnant (5/49, 10.2%). In only one aneurysm (2.0%) worsening led to aneurysm remnant with the potential risk of bleeding.

Comparing long-term anatomical results with different endovascular techniques in the subpopulation of WNBA is not easy given that most series do not follow up after 1 year and also mix wide- and narrow-neck aneurysms, and bifurcation and sidewall aneurysms. A recent series analyzed aneurysm occlusion in 108 wide-neck aneurysms at a mean follow-up delay of 58 months.19 In the group of patients treated with coiling with a single microcatheter, complete aneurysm occlusion, neck remnant, and aneurysm remnant were reported in 35.9%, 48.7%, and 15.4%, respectively, with very similar results when using a double-microcatheter technique (29.4%, 55.9%, and 14.7%, respectively). The rate of complete aneurysm occlusion is clearly lower than reported in our analysis (57.1%); yet, the rates of adequate occlusion are very similar (84.6% with a single microcatheter, 85.3% with a double microcatheter, and 87.8% in our series). An analysis of the MAPS trial also reporting follow-up at 5 years (see earlier) did not include a separate analysis of wide-neck aneurysms, and aneurysm occlusion status at 5 years is not reported.15 However, in the analysis conducted in the subgroup of wide-neck aneurysms at 1 year, anatomical results (evaluated by an independent core laboratory) after aneurysm coiling were worse compared with 5-year anatomical results in WEBCAST/WECAST-2 with complete aneurysm occlusion and adequate occlusion in 18.6% and 45.7%, respectively.20 The BRANCH trial dedicated to endovascular treatment (mixing standard coiling, BAC, and SAC) of unruptured MCA and BA apex WNBA only reported short-term (mean follow-up: 48.8 weeks) anatomical results (evaluated by an independent core laboratory) and showed rates of complete aneurysm occlusion and adequate occlusion in patients treated with coiling (including BAC and SAC) of 30.6% and 63.0%, respectively.21 When compared with flow diversion, only PUFS reports long-term (5-year) anatomical results showing a high efficacy of this treatment with complete aneurysm occlusion in 95.2%, neck remnant in 1.6%, and aneurysm remnant in 3.2%.22 These excellent results confirm that flow diversion is currently the more efficacious treatment for IAs, acknowledging that its safety is less compared with WEB aneurysm treatment, that its indications are limited to unruptured and recanalized aneurysms, and that its use in bifurcation aneurysms remains debatable. Finally, this analysis suggests that aneurysm treatment with WEB is associated with better anatomical results in the long term compared with aneurysm coiling, which is the only endovascular treatment that shares the same indications with WEB aneurysm treatment.

Retreatment rate at 5 years was 11.6% of aneurysms, which is comparable to what is reported at 1 year in the MAPS trial for aneurysms treated with coils (13.7%) or SAC (14.1%). Several endovascular techniques can be used for retreatment after WEB failure, including stenting (with or without associated coils) and flow diversion. Clipping also remains an option.23

Limitations

This study has several limitations. First, it is not a randomized study and comparison with other endovascular techniques is difficult. Consequently, building comparative studies to further evaluate the WEB device and its place in managing IAs is warranted. Second, not all patients had 5-year anatomical follow-up (only 51.6%), which is frequently the case in studies with very long-term follow-up. For example, 5-year imaging follow-up was obtained in 72.1% in PUFS.22 Third, the use of the LOCF methodology, allowing the replacement of the missing data by the last follow-up data available, leads to a certain heterogeneity of data. According to the analysis conducted in the subgroup of patients with 5-year follow-up (evolution of aneurysm occlusion between 1 year and 5 years), we cannot exclude that a limited number of patients have had a worsening of aneurysm occlusion between the last follow-up available and at 5 years. Fourth, imaging modalities used for the 5-year follow-up were heterogeneous including DSA, MRA, and CTA. DSA is an invasive technique associated with some rare complications and cannot be proposed as the first-line tool for long-term follow-up of aneurysms treated with WEB. However, MRA and CTA are effective techniques for WEB patient follow-up.24 25

Conclusions

This final analysis conducted of the combined population of two early European studies (WEBCAST/WEBCAST-2) confirms the WEB device’s safety in the treatment of wide-neck bifurcation aneurysms (WNBA) in long-term follow-up (5 years). No delayed adverse events were encountered. No mortality related to WEB was reported from the procedure to the final follow-up and procedure-related mortality was very low (1.0%). Long-term follow-up demonstrated adequate occlusion at 5 years in 77.9% of aneurysms with a low retreatment rate (11.6%).

Data availability statement

Data are available upon reasonable request.

Ethics statements

Patient consent for publication

Ethics approval

This study involved human participants and was approved by CCTIRS No. 12-247. Participants gave informed consent to participate in the study before taking part.

References

Supplementary materials

  • Supplementary Data

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Footnotes

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  • Contributors LP has provided a substantial contribution to the conception and design of the work, the acquisition, analysis, and interpretation of data for the work; drafted the work for important intellectual content; approved the final version to be published; agrees to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. IS has provided a substantial contribution to the acquisition of data for the work; revised the work critically for important intellectual content; approved the final version to be published; agrees to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. XB has provided a substantial contribution to the acquisition of data for the work; revised the work critically for important intellectual content; approved the final version to be published; agrees to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. MH has provided a substantial contribution to the acquisition of data for the work; revised the work critically for important intellectual content; approved the final version to be published; agrees to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. LSp has provided a substantial contribution to the acquisition of data for the work; revised the work critically for important intellectual content; approved the final version to be published; agrees to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. JK has provided a substantial contribution to the acquisition of data for the work; revised the work critically for important intellectual content; approved the final version to be published; agrees to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. DH has provided a substantial contribution to the acquisition of data for the work; revised the work critically for important intellectual content; approved the final version to be published; agrees to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. VC has provided a substantial contribution to the acquisition of data for the work; revised the work critically for important intellectual content; approved the final version to be published; agrees to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. JF has provided a substantial contribution to the acquisition of data for the work; revised the work critically for important intellectual content; approved the final version to be published; agrees to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. A-CJ has provided a substantial contribution to the acquisition of data for the work; revised the work critically for important intellectual content; approved the final version to be published; agrees to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. TL has provided a substantial contribution to the acquisition of data for the work; revised the work critically for important intellectual content; approved the final version to be published; agrees to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. LSt has provided a substantial contribution to the acquisition of data for the work; revised the work critically for important intellectual content; approved the final version to be published; agrees to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. WW has provided a substantial contribution to the acquisition of data for the work; revised the work critically for important intellectual content; approved the final version to be published; agrees to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. JBe has provided a substantial contribution to the acquisition of data for the work; revised the work critically for important intellectual content; approved the final version to be published; agrees to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. JM has provided a substantial contribution to the acquisition of data for the work; revised the work critically for important intellectual content; approved the final version to be published; agrees to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. AM has provided a substantial contribution to the analysis and interpretation of data for the work; drafted the work for important intellectual content; approved the final version to be published; agrees to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. JBy has provided a substantial contribution to the analysis and interpretation of data for the work; drafted the work for important intellectual content; approved the final version to be published; agrees to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.LP is acting as guarantor of the manuscript.

  • Funding Sequent funded WEBCAST and WEBCAST-2.

  • Competing interests LP reports support for the present manuscript from Microvention; consulting fees from Balt, Microvention, Perflow, Phenox, Vesalio; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing, or educational events from Balt, Microvention, Perflow, Phenox, Vesalio; support for attending meetings and/or travel from Balt, Microvention, Phenox. IS reports grants or contracts from National Brain Research Fund (Hungary); consulting fees from Stryker, Microvention, Medtronic, Cerenovus; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing, or educational events from Medtronic, Stryker, Cerenovus; support for attending meetings and/or travel from Gabriel Vegh Neurointerventional Fondation (Hungary); leadership in European Board of NeuroIntervention (EBNI), Hungarian Sociaty of Neuroradiology, Hungarian Society of Neurosurgery, Hungarian Stroke Society. XB reports consulting fees from Sequent; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing, or educational events from Sequent. MH reports consulting fees from Balt, Stryker, Medtronic, Microvention, Phenox; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing, or educational events from Cerenovus, Phenox, Stryker, Microvention, Cerus Medical. LSp reports grants or contracts from Philips (institutional); consulting fees from Balt, Medtronic, Phenox, Microvention, Stryker; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing, or educational events from Balt, Medtronic, Microvention, Stryker; support for attending meetings and/or travel from Balt, Medtronic, Microvention, Stryker. JK reports consulting fees from Microvention, Phenox. DH reports payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing, or educational events from Microvention; support for attending meetings and/or travel from Microvention. VC reports grants or contracts from Medtronic, Cerenovus, Stryker, Balt, Microvention; consulting fees from Medtronic, Stryker, Microvention; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing, or educational events from Medtronic, Stryker, Microvention; leadership in Sim & Cure. JF reports grants or contracts from Microvention (institutional); consulting fees from Microvention, Sequent; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing, or educational events from Microvention; leadership role in JNIS (Associate Editor). A-CJ reports payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing, or educational events from Microvention; leadership in European Society for Minimally Invasive Neurological Therapy (ESMINT). TL reports consulting fees from Microvention, Cerus Endovascular; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing, or educational events from Stryker, Cerus Endovascular; support for attending meetings and/or travel from Stryker, Cerus Endovascular. LSt reports no disclosures. WW reports consulting fees from Microvention. JBe reports consulting fees from Siemens (institutional). JM reports consulting fees from Microvention: other financial interests from Balt. AM reports CEC services to Sequent Medical and Microvention (institutional); payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing, or educational events from Microvention; support for attending meetings and/or travel from Microvention. JBy reports core laboratory services to Sequent Medical and Microvention (institutional); consulting fees from Oxford Endovascular Ltd and Microvention; core laboratory activities for Sequent and Microvention; leadership (Board Member) of Oxford Endovascular Ltd; stock in Oxford Endovascular Ltd.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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