Advances in endovascular technology have expanded the treatment options for intracranial aneurysms. Intrasaccular flow diversion is a relatively new technique that aims to disrupt blood inflow at the neck of the aneurysm, hence promoting intrasaccular thrombosis. The Woven EndoBridge device (WEB; MicroVention, Aliso Viejo, CA, USA) is an US Food and Drug Administration approved intrasaccular flow diverter for wide-necked aneurysms. We report the early interim clinical and radiological outcomes of patients with both ruptured and unruptured intracranial aneurysms (IAs) treated using the WEB device in an Australian population.
A retrospective analysis was done of patients with ruptured or unruptured IAs who received treatment with WEB across 5 Australian neuroendovascular referral centers between May 2017 and November 2020. Angiographic occlusion was assessed with time-of-flight magnetic resonance angiography. Complications were recorded and clinical outcomes were assessed using the modified Rankin scale at follow-up.
In total, 66 aneurysms were treated in 63 patients, with successful deployment of the WEB device in 98.5% (n=65). Eighteen (26.9%) ruptured aneurysms were included. Failure of deployment occurred in a single case. Adjunct coiling and/or stenting was performed in 20.9% (n=14) cases. Sixty-two patients with 65 aneurysms using a WEB device were followed up (mean=9.1 months), and 89.4% of these had complete aneurysm occlusion while 1.5% remained patent. Functional independence was achieved in 93.5% of cases.
Early results following the use of WEB devices in Australia demonstrate safety and adequate aneurysm occlusion comparable to international literature.
Intrasaccular flow diversion has an established role in the management of intracranial aneurysms. Ruptured intracranial aneurysms (IAs) are the most common cause of spontaneous subarachnoid hemorrhage (SAH). The prevalence of unruptured IAs varies from 3–5% [
Data from 3 Good Clinical Practice studies including WEBCAST, FRENCH Observatory, and WEBCAST-2 with a pooled cohort of 168 patients with 169 wide-necked aneurysms (≥4 mm) demonstrated complete occlusion in 52.9% and adequate occlusion in 79.1% after 1 year. A neck remnant was seen in 26.1% of participants and an aneurysm remnant in 20.9%. Retreatment was performed in 6.9% of cases [
In Australia, there has been limited implementation of WEB treatment limited to a few Neurointervention centers, leading to substantial institutional and practitioner variation in the management of candidate intracranial aneurysms as well as the follow-up and surveillance of aneurysms treated with WEB. Whether this influences patient outcomes is unknown, although it represents a major knowledge gap in practice. This multicenter study is the first to report the initial clinical experience and early interim results of the WEB device when used to treat ruptured and unruptured aneurysms in a large series within an Australian population.
A retrospective analysis was performed across 5 Australian tertiary neuroendovascular referral centers, with inclusion of patients with ruptured and unruptured intracranial aneurysms treated with the WEB device between May 2017 and November 2020. This study was approved by the institutional human research ethics committee. As specific patient information such as age or sex is not included, informed consent for publication was not required. All procedures were performed by experienced neurointerventionists (JM, DK, SL, RMFB, LS, RC, WC, AJ, DMB, and HA) and treatment decisions were made by a multidisciplinary team consisting of neurointerventionists and neurosurgeons after discussion with the patient.
Wide-necked aneurysms (i.e., neck width >4 mm and/or dome-to-neck ratio >2) were considered for treatment if the overall aneurysm morphology and location (i.e., lesion axis relative to parent vessel) appeared amenable to WEB deployment. Aneurysm sizes with a neck width of 3–10 mm and height between 3–10.5 mm were eligible to be treated with WEB and were able to accommodate the available device sizes smallest: WEB 17 single-layer (SL, 3×2 mm diameter) to largest: WEB 11 single-layer sphere (SLS, 11×9.6 mm diameter). With regards to aneurysm shape, the WEB systems are spherical (SLS) or cylindrical (SL) in shape, therefore unilobular aneurysms with spherical, cylindrical, or ovoid-shaped morphology are ideal for WEB deployment. The treatment approach was at the discretion of the treating neurointerventionist, depending on individual anatomical considerations, and aneurysms with unfavorable morphology or dimensions outside the available device sizes were excluded.
The WEB device is a braided nitinol wire structure of various shapes and sizes. Both SL and SLS designs are available, ranging from SL 4×3 mm smallest to 11×9 mm largest; SLS diameter 4 to 11 mm, height 2.6 to 9.6 mm. Proximal and distal platinum markers assist in visualization during deployment. The WEB device has increased metal coverage at its base (almost 100% at its center) [
All procedures were performed as per conventional aneurysm coil treatment under general anesthesia, procedural intravenous heparin, and with varying dual antiplatelet loading regimens in elective cases. Continuous heparinized saline flush with or without nimodipine was used during the procedure. Triaxial access was obtained using a long guidesheath in the proximal internal carotid, subclavian, or vertebral artery, a distal access catheter in the intracranial internal carotid artery (ICA) or vertebral artery, and a microcatheter within the aneurysm. The device is deployable from a microcatheter with inner diameters ranging from 0.021 to 0.033-inch, depending on the size and shape of the device, which was selected at the discretion of the treating neurointerventionist. The WEB device was sized based on width and dome height measurements obtained during 3D digital subtraction angiography using a continuous column of contrast via an injecting pump. The device was generally oversized by approximately 1 mm to ensure close apposition of the device along the aneurysm wall. During deployment, the WEB device opens up such that the base of the device is retracted to lie across the neck of the aneurysm. Control angiography is performed to confirm appropriate placement and to check for platelet aggregation prior to release of the device. Final angiography confirms aneurysm occlusion.
Immediate angiographic occlusion was graded at the time of the procedure by the treating neurointerventionist as per the WEB occlusion scale (WOS) [
Clinical outcome was assessed using the modified Rankin scale (mRS) at follow-up within 6 weeks following treatment. Complications were recorded in the procedural report and were readily available for review.
A total of 67 aneurysms in 64 patients were identified with attempted WEB treatment with an overall successful deployment of the WEB device in 98.5% (n=66) of cases. Follow-up data were available for 65 aneurysms in 62 patients in our retrospective analysis. Baseline population characteristics are outlined in
The median age was 63 (range 28–87) years, and most patients were female (75%). Eighteen (26.9%) ruptured aneurysms were included, most of which were World Federation of Neurosurgical Surgeons grade 1 presentations (12 of 18, 66.7%). Most aneurysms were in the anterior circulation (n=37, 55.2%). Three middle cerebral artery (MCA) bifurcation aneurysms were also included. The median aneurysm dome height was 5.8 mm (range 2.8–14 mm) with a median neck width of 3.5 mm (range 1.6–9.9 mm). Thirteen patients (20%) had undergone prior treatment for intracranial aneurysms. Three patients received 2 WEB devices each. In 1 of these patients, 2 WEB devices were deployed during the same procedure in distal pericallosal artery and anterior communicating artery (ACOM) aneurysms.
One patient with an unruptured 3×4 mm left ICA terminus aneurysm suffered an acute clinical deterioration post WEB deployment secondary to a large intraparenchymal hemorrhage distal to the treated aneurysm. The patient had previously had right MCA and right ICA aneurysms treated 6 weeks prior (with a WEB and coil embolization respectively) and had been on dual antiplatelet therapy after deployment of a right ICA stent during the first procedure. Additional left anterior temporal artery and right M1 aneurysms were treated during the same session. The exact cause of this was unknown and ultimately resulted in significant permanent neurological morbidity (mRS 5). Another patient with a treated wide-necked 7 mm basilar tip aneurysm subsequently died following the rupture of a separate untreated giant ACOM aneurysm several weeks after treatment (mRS 6).
A total of 62 patients with 65 aneurysms with a WEB device were followed up with multisequence MRI and non-contrast TOF MRA between 2 weeks and 31 months post-procedure. Fifty-nine of these had complete aneurysm occlusion (WOS A&B: 89.4%) and 1 remained patent (WOS D: 1.5%). Adequate occlusion was achieved in 1 patient with failed WEB deployment in which multiple soft Medtronic coils were used (modified Raymond–Roy occlusion RAY 3A) on their most recent follow-up imaging. There were initially 2 patients with WOS D occlusion and they both had identifiable sizing issues during deployment. Retreatment using stent-assisted coiling was successfully performed in 1 of these patients who went on to achieve WOS B on subsequent imaging. The second patient improved to WOS C on their most recent imaging.
Our results are comparable to a previously published case series with an overall technical success rate of 98.5%, with only a single patient showing an unfavorable angle that precluded safe device deployment. Pierot et al. [
Of 18 ruptured aneurysms, there was 1 mortality; and of the remaining 17 at mid-term follow-up, 14 achieved WOS A&B (82.4%), 2 were WOS C (11.8%), and 1 was WOS D (5.9%). This is comparable to the reported literature, as Youssef et al. [
A second patient suffered a delayed large intraparenchymal hemorrhage with permanent morbidity (mRS of 5 at 3 months) after treatment of several aneurysms in a single session including deployment of an SL 5×3 WEB into a 5 mm left ICA terminus aneurysm and concomitant coiling of left anterior temporal artery and right M1 aneurysms.
The use of endosaccular coiling for many intracranial aneurysms gained acceptance following the ISAT trial after it demonstrated an increased disability-free survival at 7 years compared to neurosurgical clipping [
As an intrasaccular flow diverter, the WEB device allows the treatment of more complex wide-necked aneurysms which are less suitable for other endovascular devices. One-year retreatment rates are low, ranging from 6% [
Wide-necked bifurcation aneurysms have traditionally been more difficult to treat endovascularly. A meta-analysis of 36 studies found that factors related to short-term angiographic obliteration include unruptured status, location in the anterior circulation, a medium neck (4–9.9 mm), use of newer-generation WEB, and treatment without additional devices [
Known complications of the WEB device include failed deployment, thromboembolic events, and intracranial hemorrhage either from aneurysm rupture or vessel perforation. Goertz et al. [
Like previous studies, we encountered no periprocedural or postprocedural deaths suggesting that the mortality risk associated with WEB is low. This high safety profile is likely to continue into the long-term, with WEB-IT and Pierot et al. [
The present analysis is limited by its retrospective nature and potential for patient selection bias. The small cohort of patients is heterogeneous with aneurysms varying in location, morphology, and clinical presentation limiting generalizability. Furthermore, the short interval for follow-up for many of these patients may not account for delayed neck recanalization. Further long-term follow-up will be required. While all patients were followed up with MRI as per our standard post embolization protocol, it remains to be seen whether MRI is the most appropriate and accurate method in which to assess aneurysm occlusion after WEB deployment. While interobserver reproducibility was excellent for contrast-enhanced (CE)-MRA (κ=0.92; 95% confidence interval [95% CI], 0.76–1.00) and moderate (κ=0.59; 95% CI, 0.30–0.88) for 3D TOF, Timsit et al. [
Early results following the use of WEB devices in Australia demonstrate safety and adequate aneurysm occlusion comparable to international literature.
All investigators freely volunteered their time towards this project. Department of Radiology, Austin Health, Melbourne, VIC, Australia. Department of Radiology, Monash Health, Melbourne, VIC, Australia. Department of Radiology, St. Vincent’s Health, Melbourne, VIC, Australia. Department of Radiology, Canberra Hospital, ACT Health, Canberra, NSW, Australia. Department of Radiology, Royal Hobart Hospital, Hobart, TAS, Australia. Department of Radiology, Royal North Shore Hospital, Sydney, NSW, Australia.
None.
Low Negligible Risk Study, retrospective, approved by local institutional review board. As specific patient information such as age or sex is not included, Informed consent for publication is not required.
The authors have no conflicts to disclose.
Concept and design: HA. Analysis and interpretation: JG, JM, and HA. Data collection: JG, YR, AL, DN, JH, DK, DT, SL, RMFB, JR, LS, RC, WC, AJ, DMB, and HA. Writing the article: JG and JM. Critical revision of the article: JG, JM, MF, YR, AL, DN, JH, DK, DT, SL, RMFB, JR, LS, RC, WC, AJ, DMB, and HA. Final approval of the article: JM and HA. Statistical analysis: JG, MF, and HA. Overall responsibility: HA.
Baseline demographics and aneurysm location, size, and morphology
Population characteristics | Value | ||
---|---|---|---|
Age (y) | 63 (28–87) | ||
Sex, female | 48 (75.0) | ||
Past history of previously treated aneurysm | 13 (20.0) | ||
Ruptured aneurysm | Total | 18 (26.9) | |
WFMS grade | 1 | 12 (17.9) | |
2 | 3 (4.5) | ||
3 | 0 (0.0) | ||
4 | 0 (0.0) | ||
5 | 3 (4.5) | ||
GCS at presentation | 15 | 57 (86.4) | |
14 | 0 (0.0) | ||
13 | 4 (6.1) | ||
12 or less | 5 (7.6) | ||
Aneurysm location | Anterior circulation | Total (anterior) | 37 (55.2) |
Carotid (terminus/paraopth) | 17 (25.4) | ||
ACOM | 14 (20.9) | ||
MCA | 4 (6.0) | ||
ACA (pericallosal) | 2 (3.0) | ||
Posterior circulation | Total (posterior) | 30 (41.8) | |
Basilar | 20 (28.4) | ||
PCOM | 6 (9.0) | ||
SCA | 3 (3.0) | ||
PCA | 1 (1.5) | ||
Aneurysm dome width (mm) | 5.5 (3–12.2) | ||
Aneurysm dome height (mm) | 5.8 (2.8–14) | ||
Aneurysm neck width (mm) | 3.5 (1.6–9.9) |
Values are presented as median (range) or number (%).
WFNS, World Federation of Neurosurgical Surgeons; GCS, Glasgow coma scale; ACOM, anterior communicating artery; MCA, middle cerebral artery; ACA, anterior cerebral artery; PCOM, posterior communicating artery; SCA, superior cerebellar artery; PCA, posterior cerebral artery.
Periprocedural antiplatelet use, procedural outcomes, and immediate angiographic occlusion
Procedural technique | Value | |
---|---|---|
Preprocedural antiplatelet agents | Nil | 19 (28.8) |
Any | 47 (71.2) | |
Aspirin/clopidogrel | 42 (63.6) | |
Aspirin | 2 (3.0) | |
Clopidogrel | 2 (3.0) | |
Aspirin/prasugrel | 1 (1.5) | |
Intraprocedural anticoagulant +/– antiplatelet agents | Nil | 3 (4.5) |
Any | 63 (95.5) | |
Heparin | 57 (86.4) | |
Heparin/IV aspirin | 5 (7.6) | |
Heparin/intergrillin | 1 (1.5) | |
Postprocedural antiplatelet agents | Nil | 1 (1.5) |
Any | 65 (98.5) | |
Aspirin | 54 (81.8) | |
Aspirin/clopidogrel | 8 (12.1) | |
Aspirin/prasugrel | 1 (1.5) | |
Clopidogrel | 2 (3.0) | |
Device Failure | 1 (1.5) | |
Adjunct device used | Nil | 50 (74.6) |
Any | 17 (25.4) | |
Coils | 11 (16.4) | |
Balloon assisted | 3 (4.5) | |
LVIS stent | 3 (4.5) | |
Need for resizing WEB device | 4 (6.0) | |
Immediate modified WOS | Complete occlusion (WOS A&B) | 58 (86.6) |
Residual neck (WOS C) | 6 (9.2) | |
Residual aneurysm (WOS D) | 2 (3.1) | |
Immediate mRROC | RAY 3A | 1 (1.5) |
Values are presented as number (%).
Nil, none; IV, intravenous; LVIS, Low-profile visualized intraluminal support device (MicroVention Inc., Aliso Viejo, CA, USA); WOS, WEB occlusion scale; mRROC, modified Raymond–Roy occlusion class.
Complications, need for retreatment, follow up time, clinical outcomes, and early/interim angiographic outcomes
Morbidity and mortality | Value | ||
---|---|---|---|
Complications | Nil | 57 (89.1) | |
Any | 7 (10.9) | ||
Thromboembolism | 4 (6.3) | ||
Perforation/subarachnoid hemorrhage | 1 (1.6) | ||
Intracerebral hemorrhage | 1 (1.6) | ||
Hydrocephalus requiring VP-shunt insertion | 1 (1.6) | ||
Mortality | 1 (2) | ||
Procedure related mortality | 0 (0) | ||
Need for retreatment | Not required | 64 (98.5) | |
Retreatment performed | 1 (1.5) | ||
Follow-up time (mo) | Mean | 9.1 | |
Minimum | 0.5 | ||
Maximum | 31.3 | ||
Follow-up mRS | mRS (0–2) | 58 (93.5) | |
0 | 54 (87.1) | ||
1 | 3 (4.8) | ||
2 | 1 (1.6) | ||
mRS (3–6) | 4 (6.5) | ||
3 | 3 (4.8) | ||
4 | 1 (1.6) | ||
5 | 0 (0) | ||
6 | 0 (0) | ||
Follow-up modified WOS | Complete occlusion (WOS A&B) | 59 (89.4) | |
Residual neck (WOS C) | 5 (7.6) | ||
Residual aneurysm (WOS D) | 1 (1.5) | ||
Follow-up mRROC | RAY 2A | 1 (1.5) |
Values are presented as number (%).
Nil, none; VP-shunt, ventriculo-peritoneal shunt; mRS, modified Rankin scale; WOS, WEB occlusion scale; mRROC, modified Raymond–Roy occlusion class.