The impact of pre-treatment aneurysm angulation. What happens with WEB devices at follow-up?

BACKGROUND

WEB shape modification has been analyzed in relation to the aneurysm occlusion outcome and techniques have been presented with one-dimensional measurements of the device to quantify the change after implantation. In this work, we present an analysis of pre-treatment vascular morphology and hemodynamics of cases treated with WEB devices, which were three-dimensionally quantified in morphology and position to detect modifications.

METHODS

Seventeen WEB-treated aneurysms with pre-treatment, post-treatment and follow-up 3D flat-panel CT were included. Three-dimensional measurements of the WEB morphology and position were made at post-treatment and at follow-up. Differences between acquisitions of all measured variables were statistically evaluated (Wilcoxon signed-rank paired test, P-value = 0.05). Pre-treatment aneurysm angles were three-dimensionally measured and CFD simulations were performed to evaluate the influence of flow on WEB changes.

RESULTS

WEB height and diameter presented statistically significant changes. Modification of the angle between the WEB axis and parent artery was significantly higher in the group with WEB shape modification (Mann-Whitney U test, P < 0.05). In this group, the median pre-treatment aneurysm angle was smaller than in the group without shape modification (8.16° vs. 13.14°, P = 0.06). Inflow ratio was higher in the WEB shape modification group.

CONCLUSIONS

An association between the magnitude of morphological changes of the WEB with the direction of its axis within the aneurysm was found. The analysis of pre-treatment morphological and hemodynamic conditions would allow the detection of aneurysm cases in which the WEB will undergo a more pronounced modification.

Validity of Woven EndoBridge sizing based on the device-to-aneurysm volume ratio

BACKGROUND

The Woven EndoBridge (WEB) is a treatment modality available for the treatment of intracranial aneurysms, specifically beneficial in wide-necked bifurcation aneurysms. Conventional sizing methods rely on the manipulation of aneurysm width and height measurements. This results in frequent need for re-sizing after initial WEB insertion attempts. Previous studies have suggested that volume-based sizing may decrease this rate.

METHODS

We conducted a multicenter retrospective cohort study in three complex vascular centers in the United States from 1 January 2020 to 30 June 2023. All patients who underwent attempted aneurysmal WEB embolization were included. Using three-dimensional angiogram reconstructions, we measured the aneurysm volume. We calculated the WEB volume and measured the WEB-aneurysm volume (WAVe) ratio. The primary outcome was whether a WEB required re-sizing.

RESULTS

A total of 133 cases were identified, 114 correctly sized and 19 incorrectly sized. Twelve patients (9.0%) required additional stent placement during WEB insertion. One patient (0.8%) had WEB abandonment. There were no differences in demographic or baseline characteristics between the size/re-sizing cohorts aside from aneurysm location ("other" and basilar locations increased the rate of re-sizing). The median WAVe ratio in our appropriately sized cohort was 0.997 (interquartile range (IQR) 0.826, 1.30) versus 1.14 in our re-sizing cohort (IQR 0.734, 1.51; p = 0.728). Using logistic regression, we identified a WAVe ratio ranging from 0.76 to 1.24 yielding > 80% probability of a successful sizing with 95% confidence.

CONCLUSIONS

Incorporating volume-based measurements in aneurysm embolization with WEBs may improve rates of re-sizing but has an unclear effect on aneurysm occlusion. A WAVe ratio of 0.76-1.24 provides the greatest probability of appropriate initial WEB sizing.

Modification of Woven Endo-Bridge After Intracranial Aneurysm Treatment: A Methodology for Three-Dimensional Analysis of Shape and Relative Position Changes

During follow-up of patients treated with WEB devices, shape changes have been observed. The quantitative three-dimensional measurement of the WEB shape modification (WSM) would offer useful information to be studied in association with the anatomical results and try to better understand mechanisms implicated in this modification phenomenon. We present a methodology to quantify the morphology and position of the WEB device in relation to the vascular anatomy. Three-dimensional rotational angiography (3DRA) images of seven aneurysms patients treated with WEBs were used, which also accompanied by a post-treatment 3DRA image and a follow-up 3DRA image. The device was manually segmented, obtaining the 3D models after treatment and at the follow-up. Volume, surface area, height, maximum diameter and WSM ratio of both surfaces were calculated. Position changes were evaluated measuring WEB axis and relative position between post-treatment and follow-up. Changes in WEB volume and surface area were observed with a mean modification of - 5.04 % ( ± 14.19 ) and - 1.68 % ( ± 8.29 ) , respectively. The positional variables also showed differences, mean change of device axis direction was 26.25 % ( ± 24.09 ) and mean change of distance l b was 5.87 % ( ± 10.59 ) . Inter-observer and intra-observer variability analyses did not show differences (ANOVA p > 0.05 ). This methodology allows quantifying the morphological and position changes suffered by the WEB device after treatment, offering new information to be studied in relation to the occurrence of WEB shape modification.

Endovascular Treatment of Bifurcation Aneurysms with the Woven EndoBridge: Product Features and Selected Results of Off-Label Use

Treatment for wide-neck bifurcation cerebral aneurysms (WNBAs) is widely performed by endovascular treatment as well as open surgical clipping. However, due to factors such as the shape and size of the aneurysms, as well as the anatomical features of surrounding branch vessels, there are some cases in which simple coiling or conventional adjunctive techniques, such as balloon-assisted or neck bridge stent-assisted coiling, are not sufficient to achieve a satisfactory cure. Against this backdrop, the device known as the Woven EndoBridge (WEB) (MicroVention, Aliso Viejo, CA, USA) was developed and can be deployed directly into the aneurysm for treatment. Over a decade has passed since its development, and it is now used in many countries worldwide. This review provides insights into the evolution of the WEB device from its development to the date of this writing, highlighting the unique features of the device and its treatment indications. Additionally, it discusses the posttreatment course, perspectives on recurrence and retreatment, imaging assessments, and potential off-label use based on numerous studies primarily conducted in Europe and the USA.

WEB shape modifications: angiography-histopathology correlations in rabbits

BACKGROUND

WEB Shape Modification (WSM) over time is frequent after aneurysm treatment. In this study, we explored the relationship between histopathological changes and angiographic evolution over time in experimental aneurysms in rabbits treated with the Woven EndoBridge (WEB) procedure.

METHODS

Quantitative WSM was assessed using flat-panel computed tomography (FPCT) during follow-up by calculating height and width ratio (HR, WR), defined as the ratio between either measurement at an index time point and the measurement immediately after WEB implantation. The index time point varied from 1 day to 6 months. HR and WR were evaluated with angiographic and histopathological assessments of aneurysm healing.

RESULTS

Final HR of devices varied from 0.30 to 1.02 and final WR varied from 0.62 to 1.59. Altogether, at least 5% of HR and WR variations were observed in 37/40 (92.5%) and 28/40 (70%) WEB devices, respectively, at the time of final assessment. There was no significant correlation between complete or incomplete occlusion groups and HR or WR (p=0.15 and p=0.43). Histopathological analysis revealed a significant association between WR and aneurysm healing and fibrosis 1 month following aneurysm treatment (both p<0.05).

CONCLUSION

Using longitudinal FPCT assessment, we observed that WSM affects both the height and width of the WEB device. No significant association was found between WSM and aneurysm occlusion status. Although presumably a multifactorial phenomenon, the histopathological analysis highlighted a significant association between width variations, aneurysm healing and fibrosis in the first month following aneurysm treatment.

Woven Endo Bridge shape modification contributes to decrease in adequate occlusion rate after Woven Endo Bridge implantation for wide-neck bifurcation intracranial aneurysms

PURPOSE

Recently, a novel device, the Woven Endo Bridge (WEB), was developed for wide-neck bifurcation intracranial aneurysms (WNBAs). The aim of this study is to investigate factors that contribute to adequate occlusion (AO) after the operation using detailed radiological images.

METHODS

The subjects were 29 patients with 29 aneurysms who received WEB implantation for WNBAs between December 2020 and April 2022. We assessed the contributing factors to AO by retrospectively comparing the AO group and non-AO group.

RESULTS

The mean age was 64.6 ± 13.1 years, and 18 were female (62.1%). The mean aneurysm dome width, aneurysm height, and aneurysm neck diameter were 4.8 ± 0.6 mm, 5.1 ± 0.6 mm, and 3.7 ± 0.6 mm, respectively. After about 6 months, 22 of 29 patients (75.9%) had AO. Complications were observed in 2 patients (6.9%), renal artery injury in one, and minor cerebral infarction in another, but the modified Rankin scale scores of both patients remained unchanged. Multivariate analysis extracted only WEB shape modification (WSM) as a contributing factor to AO (odds ratio: 0.912, p = 0.0287).

CONCLUSION

WEB implantation for WNBAs was a treatment modality with acceptable efficacy and safety. WSM was the only significant factor contributing to non-AO after the treatment. We should clarify the mechanisms or causes of WSM to achieve AO after WEB implantation in future.

Mid-to-long term safety and efficacy of Woven EndoBridge device for Treatment of intracranial wide neck aneurysms: A systematic review and meta-analysis

BACKGROUND

In recent 10 years, Woven EndoBridge(WEB) device has been used as endovascular instrumentation for treating wide neck Bifurcation aneurysms. Its safety and efficacy in the mid-term (6-24 months) and long-term (more than 24 months) follow-up period have yet to be systematically reviewed.

PURPOSE

To evaluate the WEB device safety and efficacy, relevant literature and publications were extensively reviewed, and a meta-analysis was conducted.

DATA RESOURCE

All relevant literature/publications were achieved from Pubmed, Cochrane, Embase, and Web of Science databases.

RESULTS

767 patients that were studied in 13 literature were included. The focus of this review was placed on the clinical and anatomic outcomes. Complete occlusion was achieved in 67.3% (95% CI, 59.0-75.5%) and 69.3% (95% CI, 55.7-82.8%) of the cases at mid- and long-term follow-up. The rate of adequate occlusion was 86.6% (95% CI, 83.0-90.2%) and 90.1% (95% CI, 85.5-94.4%) for the mid and long-term, respectively. 51 patients (8.8%; 95% CI,5.6-11.9%) and 18 (8.1%; 95% CI,0.8-15.5%) received retreatments during mid- and long-term follow-up, respectively. 410 patients from 427 (94.3%; 95% CI, 89.7-98.9%) showed favorable clinical outcomes. The all-cause mortality rate was 3.5% (95% CI, 1.4-5.6%), where only a few cases were related to the WEB implantation. The WEB device deployment was associated with an overall clinical complication rate of 4.1% (95% CI, 2.7-6.6%), 3 hemorrhagic (1.2%; 95% CI, 0.2-2.6%), and 30 thromboembolic (4.0%; 95% CI, 4.0- 6.0%) complications.

CONCLUSIONS

The findings reveal the satisfactory safety and effectiveness of the WEB device for the Treatment of wide-neck aneurysms during mid-to-long-term follow-up, indicating the high potential of the WEB device for wide application.

Delayed rupture of an anterior communicating artery aneurysm after elective Woven EndoBridge embolization, re-treated with microsurgical clipping: operative technique and systematic review

BACKGROUND

The Woven EndoBridge (WEB) device is designed for intrasaccular flow disruption for embolization of intracranial aneurysms. In limited experience so far, the rate of rupture after adequate occlusion by embolization is low.

TECHNICAL REPORT

A 58-year-old man initially had an incidental, unruptured 10.4 mm anterior communicating artery (ACoA) aneurysm treated with WEB embolization. Although his 6-month follow-up angiogram showed adequate occlusion of the aneurysm, he presented to our facility with aneurysmal recurrence due to WEB compaction and rupture. This was treated with surgical clipping of the aneurysm.

METHODS

The literature was systematically reviewed for cases of delayed rupture after WEB embolization. Statistical analyses included studies with at least 20 patients and follow-up of 3 months.

RESULTS

We identified 36 studies, which were primarily retrospective observational studies. The rate of complete occlusion ranged from 33% to 89%, and the rate of re-treatment ranged from 1.5% to 27%. Across four studies, the rate of recanalization ranged from 8.7% to 13%. Two cases of delayed rupture were reported; an additional four cases were found in case reports and case series. In only one previous case, the aneurysm was reported as previously untreated.

CONCLUSION

Early retrospective data has begun to define the history of WEB-treated aneurysms. Rupture of a previously unruptured, WEB-treated aneurysm with adequate initial occlusion is rare. We describe such a case with techniques for management, demonstrating that aneurysm recurrence and delayed rupture is possible despite good interim angiographic result. This report raises questions about follow-up for WEB-treated aneurysms.

Woven EndoBridge in Wide-Neck Bifurcation Aneurysms: Digital Subtraction Angiography at 3-Year Follow-Up

Introduction: The Woven EndoBridge (WEB) device is a self-expanding intrasaccular braided-wire device for the treatment of wide-neck bifurcation aneurysms (WNBAs). Even though this device has an excellent safety profile and a low risk of rebleeding, little is known about its long-term effects. Material and Methods: All patients treated with WEB due to ruptured WNBAs were subjected to follow-up digital subtraction angiography (DSA) at 2 and 3 years after device deployment. The degree of residual neck was assessed through BOSS, Lubicz, and WEBCAST scales. Data on modified Rankin scale (mRS), bleeding events, and ischemic events occurring during this time period were collected as well. Lastly, overall and procedure-related mortality rates were calculated. Results: A total of 21 patients were treated between 1 January 2016, and 31 December 2018. DSA demonstrated a patency grade of 57.1% and 61.1% at 2 and 3 years, respectively. The overall 2-year mortality rate due to causes unrelated to the aneurysm was 14.3%. None of the patients were retreated between the 2- and the 3-year follow-up. No rebleeding or stroke events occurred during the follow-up. Conclusions: WEB-treated ruptured aneurysms showed an excellent degree of stability over time. The overall mortality rate—unrelated to the procedure–observed in our sample was higher than what reported in the literature, a possible bias associated with the COVID-19 pandemic.