Impact of A1 Asymmetry on the Woven EndoBridge Device in Anterior Communicating Artery Aneurysms

BACKGROUND AND PURPOSE:Woven EndoBridge (WEB) devices are increasingly used to treat intracranial aneurysms. A1 asymmetry contributes to anterior communicating artery aneurysm formation and to treatment instability after coiling. We sought to evaluate whether A1 asymmetry had an impact on angiographic outcome in anterior communicating artery aneurysms treated with the WEB.MATERIALS AND METHODS:Anterior communicating artery aneurysms treated between July 2012 and July 2020 with the WEB from an institutional review board–approved database were reviewed. A1 asymmetry was categorized as the following: absence of the A1 segment on 1 side (unilateral A1) versus bilateral A1. Univariate and multivariable analyses assessed independent predictors of adequate (WEB Occlusion Scale A, B, and C) and complete occlusion (WEB Occlusion Scale A and B).RESULTS:Forty-eight individual aneurysms (47 patients) were included in the final analysis, of which 16 (33%) were acutely ruptured. The mean size was 6.5 (SD, 2.2) mm. Adequate and complete occlusion was achieved in 33 (69%) and 30 (63%) cases, respectively. Unilateral A1 was associated with significantly higher rates of adequate (92% versus 60% for bilateral A1; P = .03) and complete occlusion (92% versus 50% for bilateral A1; P < .01). Multivariable logistic regression confirmed unilateral A1 as an independent predictor of both adequate (OR = 10.6; 95% CI, 1.6–220.7; P = .04) and complete occlusion (OR = 9.5, 95% CI, 1.5–190.2; P = .04. A sensitivity analysis comparing unilateral “functional” A1 with bilateral “functional” A1 showed similar results. WEB shape modification was not influenced by the unilateral A1 configuration (P = .70).CONCLUSIONS:Anterior communicating artery aneurysms with a unilateral A1 configuration treated with WEB devices are associated with better angiographic outcome than those with bilateral A1. This finding supports the hypothesis that WEB devices are resistant to unilateral flow in the aneurysm as opposed to coils.

The efficacy and safety of the Woven EndoBridge device (WEB; MicroVention) have been widely reported in several observational studies and in prospective trials.^1,2 The device is now a reliable option for the treatment of wide-neck aneurysms. Two recent meta-analyses of WEB device use found that overall rates of complete and adequate occlusion were 53% and 80%–83.3%, respectively.^3,4The anterior communicating artery (ACoA) is a preferred site for aneurysms,⁵ and aneurysms in this location tend to have a higher risk of rupture than aneurysms in other locations.^6,7 Because of the wide variety and complexity of the anterior communicating artery anatomy, ACoA aneurysms are usually considered the most complex ones to treat. Several endovascular devices (coils, stent-assisted coiling, and flow diverters) have been specifically reported in this location to overcome this challenge.^8-10 Most pointed out the role of A1 asymmetry on the angiographic outcome.^8,10 In this situation, the WEB device appears to be an appealing solution: It can be used in wide-neck aneurysms without a stent. However, the influence of the ACoA anatomy on WEB devices is not known.Here, we aimed to report the angiographic outcomes of ACoA aneurysms treated with the WEB and to determine whether A1 asymmetry has an impact on the treatment outcome.     

Endovascular Treatment of Wide-Neck Anterior Communicating Artery Aneurysms Using WEB-DL and WEB-SL: Short-Term Results in a Multicenter Study

BACKGROUND AND PURPOSE:Endovascular treatment of wide-neck anterior communicating artery aneurysms can often be challenging. The Woven EndoBridge (WEB) device is a recently developed intrasaccular flow disrupter dedicated to endovascular treatment of intracranial aneurysms. The aim of this study was to investigate the feasibility, safety, and efficacy of the WEB Dual-Layer and WEB Single-Layer devices for the treatment of wide-neck anterior communicating artery aneurysms.MATERIALS AND METHODS:Patients with anterior communicating artery aneurysms treated with the WEB device between June 2013 and March 2014 in 5 French centers were analyzed. Procedural success, technical complications, clinical outcome at 1 month, and immediate and 3- to 6-month angiographic follow-up results were analyzed.RESULTS:Ten patients with unruptured anterior communicating artery aneurysms with a mean neck diameter of 5.4 mm were treated with the WEB. Treatment failed in 3 of the 10 aneurysms without further clinical complications. One patient developed a procedural thromboembolic event, and the other 6 had normal neurologic examination findings at 1-month follow-up. Immediate anatomic outcome evaluation showed adequate occlusion (total occlusion or neck remnant) in 6 of 7 patients. Angiographic control was obtained in all patients, including 6 adequate aneurysm occlusions (3 complete occlusions and 3 neck remnants) at short-term follow-up.CONCLUSIONS:In our small series, treatment of wide-neck anterior communicating artery aneurysms with the WEB device was feasible and safe. However, patient selection based on the aneurysm and initial angiographic findings in the parent artery is important due to the limitations of the WEB device navigation.

Coiling of intracranial aneurysms is now a well-established endovascular treatment option.^1,2 Nevertheless, in cases of wide-neck aneurysms, coiling alone has often been proved unsuitable. Balloon-assisted and stent-assisted coiling may be therapeutic options.^3–5 However, low rates of initial angiographic occlusion and high rates of recurrence are reported in such situations.^5–7 In addition, bifurcation aneurysms often require an X- or Y-configuration double-stent treatment technique that carries a higher rate of procedural complications^8–13 in addition to the complications linked to the mandatory use of dual antiplatelet therapy.^11–13The Woven EndoBridge (WEB) aneurysm embolization system (Sequent Medical, Aliso Viejo, California) is a recently developed intrasaccular flow disruptor dedicated to intracranial wide-neck aneurysm management; to date, WEB Dual-Layer (WEB-DL) feasibility, safety, and short-term angiographic findings have only been reported in a few studies, mostly in aneurysms of the middle cerebral artery, while its feasibility and results in treatment of anterior communicating artery aneurysms are not well-known.^14–18 The characteristics of the WEB device combining a large-diameter microcatheter and a relatively stiff device may hamper its placement in this location.The goal of this study was to analyze the feasibility, safety, and efficacy of WEB-DL and WEB Single-Layer (WEB-SL) flow disruptors for the treatment of wide-neck anterior communicating artery aneurysms.     

Woven EndoBridge Intrasaccular Flow Disrupter for the Treatment of Ruptured and Unruptured Wide-Neck Cerebral Aneurysms: Report of 55 Cases

BACKGROUND AND PURPOSE:The safety and efficacy of the Woven EndoBridge (WEB) device for the treatment of cerebral aneurysms have been investigated in several studies. Most of these studies focused on specific aneurysms or a certain WEB device. Our objective was to report the experience of 2 German centers with the WEB device, including technical feasibility, safety, and short-term angiographic outcome.MATERIALS AND METHODS:We performed a retrospective study of all ruptured and unruptured aneurysms that were treated with a WEB device (WEB Double-Layer, Single-Layer, and Single-Layer Sphere) between April 2012 and August 2014. Primary outcome measures included the feasibility of the implantation and the angiographic outcome at 3-month follow-up. Secondary outcome measures included the clinical outcome at discharge and procedural complications.RESULTS:Fifty-five aneurysms in 52 patients, including 14 ruptured aneurysms, underwent treatment with the WEB device. The median age of patients was 55 years (range, 30–75 years); 19/55 (37%) were men. The device could be deployed in all patients and was implanted in 51/55 (93%) cases. Procedural complications occurred in 6/51 (12%), comprising 2 thromboembolic events, 2 thrombus formations, 1 high-grade posterior cerebral artery stenosis, and 1 aneurysm rupture. None of these had clinical sequelae. Angiographic follow-up at 3 months was available for 44/51 (86%) aneurysms. A favorable angiographic result at 3 months was achieved in 29/44 (66%) cases, whereas the percentage of good anatomic results increased from 40% in 2012 to 75% in 2014.CONCLUSIONS:The WEB device proved to be safe. Acceptable occlusion rates can be achieved but seem to require wide experience with the device.

Endovascular treatment has become a widely accepted therapeutic option for ruptured and unruptured cerebral aneurysms.^1–4 Wide-neck or large aneurysms are difficult to treat by coil embolization without the use of intraluminal support devices such as balloons or stents. When these devices are used for the treatment of complex cerebral aneurysms, promising results have been reported.^5,6 Nevertheless, there are several limitations in the use of intraluminal support devices, such as the risk of interventional complications or the need for dual anitplatelet therapy in the case of stent-assisted coil embolization.^7,8 The Woven EndoBridge (WEB; Sequent Medical, Aliso Viejo, California) is an intrasaccular flow-disruption device that modifies blood flow at the aneurysm neck.⁹ Today the WEB is available in 3 different shapes: the WEB Double-Layer (DL), Single-Layer (SL) and Single-Layer Sphere (SLS).¹⁰ So far, initial clinical results have mostly been published for the WEB-DL, comprising the results of a prospective, multicenter study and several case series. Additionally, there are only very limited data about the feasibility of the WEB device for the treatment of ruptured aneurysms.¹⁰ Occlusion rates of 81%–92% have been reported when the WEB-DL was implanted.^11–13 In ruptured aneurysms, occlusion rates of 67% have been reported.¹⁰ All studies reported high rates of neck remnants, which have been shown to represent an inflow into the recess of the WEB-DL in many cases.^11–13 To our knowledge, none of these studies reflect experience with ruptured and unruptured aneurysms that have been treated with all 3 types of WEB devices.     

Contrast-Enhanced and Time-of-Flight MRA at 3T Compared with DSA for the Follow-Up of Intracranial Aneurysms Treated with the WEB Device

BACKGROUND AND PURPOSE:Imaging follow-up at 3T of intracranial aneurysms treated with the WEB Device has not been evaluated yet. Our aim was to assess the diagnostic accuracy of 3D–time-of-flight MRA and contrast-enhanced MRA at 3T against DSA, as the criterion standard, for the follow-up of aneurysms treated with the Woven EndoBridge (WEB) system.MATERIALS AND METHODS:From June 2011 to December 2014, patients treated with the WEB in our institution, then followed for ≥6 months after treatment by MRA at 3T (3D-TOF-MRA and contrast-enhanced MRA) and DSA within 48 hours were included. Aneurysm occlusion was assessed with a simplified 2-grade scale (adequate occlusion [total occlusion + neck remnant] versus aneurysm remnant). Interobserver and intermodality agreement was evaluated by calculating the linear weighted κ. MRA test characteristics and predictive values were calculated from a 2 × 2 contingency table, by using DSA data as the standard of reference.RESULTS:Twenty-six patients with 26 WEB-treated aneurysms were included. The interobserver reproducibility was good with DSA (κ = 0.71) and contrast-enhanced-MRA (κ = 0.65) compared with moderate with 3D-TOF-MRA (κ = 0.47). Intermodality agreement with DSA was fair with both contrast-enhanced MRA (κ = 0.36) and 3D-TOF-MRA (κ = 0.36) for the evaluation of total occlusion. For aneurysm remnant detection, the prevalence was low (15%), on the basis of DSA, and both MRA techniques showed low sensitivity (25%), high specificity (100%), very good positive predictive value (100%), and very good negative predictive value (88%).CONCLUSIONS:Despite acceptable interobserver reproducibility and predictive values, the low sensitivity of contrast-enhanced MRA and 3D-TOF-MRA for aneurysm remnant detection suggests that MRA is a useful screening procedure for WEB-treated aneurysms, but similar to stents and flow diverters, DSA remains the criterion standard for follow-up.

Endovascular treatment is now the first-line treatment for the management of ruptured and unruptured intracranial aneurysms.^1–4 However, the limitations of standard coiling for complex aneurysms (large, wide-neck, or developed in a bifurcation) have contributed to the development of new endovascular approaches, including balloon-assisted coiling, stent-assisted coiling, flow diversion, and flow disruption.⁵The Woven EndoBridge (WEB) aneurysm embolization system (Sequent Medical, Aliso Viejo, California) is an intrasaccular device designed to disrupt the intra-aneurysmal flow at the level of the neck.^6,7 Initial experience with the WEB–Dual-Layer (DL) showed the clinical utility of this device in wide-neck bifurcation aneurysms with high technical success and low acute morbidity and mortality.^6–16 Several WEB devices are now available, including Single-Layer (WEB-SL), Single-Layer Sphere (WEB-SLS), and WEB-DL subtypes.^12,13 Recently, Enhanced-Visualization (EV) versions were developed to improve fluoroscopic visualization of the devices during treatment.Because of the potential risk of aneurysm recanalization after endovascular treatment, regular imaging follow-up is recommended. Digital subtraction angiography is the criterion standard for the follow-up of intracranial aneurysms after endovascular treatment but has some disadvantages, including potential neurologic complications, iodinated contrast injection, and radiation exposure. With the goal of avoiding DSA drawbacks, several MR angiography techniques have been tested to follow intracranial aneurysms. 3D-TOF-MRA and contrast-enhanced MRA (CE-MRA) at 3T are appropriate techniques for the follow-up of coiled aneurysms but have some limitations for the aneurysms treated with stents or flow diverters.^17–23 Because the WEB is a relatively new device, the value of 3D-TOF-MRA and CE-MRA for the follow-up of WEB-treated intracranial aneurysms has been evaluated in a small number of patients at 1.5T.²⁴The aim of this single-center prospective study was to assess the diagnostic accuracy of 3D-TOF-MRA and CE-MRA at 3T against DSA, as the criterion standard, for the evaluation of aneurysm occlusion after WEB treatment.     

WEB-DL Endovascular Treatment of Wide-Neck Bifurcation Aneurysms: Long-Term Results in a European Series

BACKGROUND AND PURPOSE:Flow disruption with the WEB-DL device has been used safely for the treatment of wide-neck bifurcation aneurysms. The stability of aneurysm occlusion after this treatment was evaluated in the short and midterm, but not in the long term. This retrospective multicenter European study is the continuation of an already published series dealing with short- and midterm anatomic results and analyzes long-term data in patients treated with the WEB-DL.MATERIALS AND METHODS:Twelve European neurointerventional centers initially participated in the study. In addition to data collected for the initial publication, images obtained at long-term follow-up were collected and independently analyzed by the same experienced interventional neuroradiologist.RESULTS:Of the initial 45 patients, 26 (20 women and 6 men; 35–73 years of age; mean, 55.2 ± 10.6 years; median, 55.5 years) with 26 aneurysms treated with the WEB-DL device had long-term follow-up (median, 27.4 months). Three of 26 patients (11.5%) were retreated between short- and midterm follow-up, and none, between mid- and long-term follow-up. Long-term aneurysm occlusion in the 19 patients treated with the WEB only and not retreated during follow-up was complete occlusion in 13/19 patients (68.4%), including aneurysms with opacification of the proximal recess in 9/19 patients (47.4%), neck remnant in 3/19 patients (15.8%), and aneurysm remnant in 3/19 patients (15.8%). In all patients (100.0%), aneurysm occlusion was stable between midterm and long-term follow-up.CONCLUSIONS:The results suggest that WEB treatment of wide-neck bifurcation aneurysms offers long-term stable occlusion.

Endovascular treatment is now the first-line treatment for both ruptured and unruptured intracranial aneurysms.^1–4 However, the limitations of standard coiling have contributed to the development of new endovascular approaches, including balloon-assisted coiling, stent-assisted coiling, flow diversion, and flow disruption.⁵The WEB aneurysm embolization system (Sequent Medical, Aliso Viejo, California) is an intrasaccular device designed to disrupt the intra-aneurysmal flow at the level of the neck.^6–9 Several devices are now available in the WEB family: WEB–Dual Layer (DL) and the more recently introduced WEB–Single Layer (SL) and WEB–Single Layer Sphere (SLS).¹⁰ Initial clinical experience and recent multicenter series have shown the clinical utility of this device in wide-neck bifurcation aneurysms with high technical success and low acute morbidity and mortality.^7–11 Also, the initial WEB-DL literature suggested good efficacy with a high percentage of complete and adequate occlusion (complete occlusion or neck remnant) in the postoperative period and in the short-term follow-up. In the WEB Clinical Assessment of IntraSaccular Aneurysm Therapy (WEBCAST) trial, complete and adequate occlusion was observed in, respectively, 56.1% and 85.4% of aneurysms.¹¹ A retrospective series evaluating both short- (median, 6 months) and midterm (median, 13 months) follow-up showed adequate occlusion in, respectively, 81.1% and 89.7% of aneurysms.¹² Between short- and midterm follow-up, aneurysm occlusion was stable in 92.9% of aneurysms.Aneurysm recanalization is an important issue in endovascular therapy, and wide-neck aneurysms (typical indications for the WEB) are highly prone to recanalization.^13,14 Because the WEB is dedicated to the treatment of wide-neck bifurcation aneurysms, it is important to assess the long-term stability of aneurysm occlusion after WEB treatment. As a multicenter trial, the European study was already conducted in the first patients treated with the WEB; therefore, the decision was made to collect and analyze long-term follow-up in this series of patients when available.¹² In this initial series, it was shown that opacification of the proximal recess was always stable at midterm and that it was equivalent to complete occlusion.¹²     

Safety and Efficacy of Aneurysm Treatment with the WEB: Results of the WEBCAST 2 Study

BACKGROUND AND PURPOSE:Flow disruption with the Woven EndoBridge (WEB) device is an innovative technique for the endovascular treatment of wide-neck bifurcation aneurysms. The initial version of the device (WEB Double-Layer) was evaluated in the WEB Clinical Assessment of IntraSaccular Aneurysm Therapy (WEBCAST) study, whereas the French Observatory study evaluated both WEB Double-Layer and Single-Layer versions of the device. WEBCAST 2 was designed to evaluate the WEB Single-Layer with Enhanced Visualization.MATERIALS AND METHODS:Patients with wide-neck bifurcation aneurysms for which WEB treatment was possible were included. Clinical data including adverse events and clinical status at 1 month and 1 year were collected and analyzed. A core laboratory evaluated anatomic results at 1 year following the procedure.RESULTS:Ten European neurointerventional centers included 55 patients (38 women; 27–77 years of age; mean, 54.4 ± 10.0 years) with 55 aneurysms. Aneurysm locations were the middle cerebral artery in 25 aneurysms (45.5%), the anterior communicating artery in 16 (29.1%), the basilar artery in 9 (16.4%), and the internal carotid artery terminus in 5 (9.1%). Procedural morbidity and mortality at 1 month were, respectively, 1.8% (1/55 patients) and 0.0% (0/55 patients). Morbidity and mortality at 1 year were, respectively, 3.9% (2/51 patients) and 2.0% (1/51 patients). At 1 year, complete occlusion was observed in 27/50 aneurysms (54.0%); neck remnant, in 13/50 (26.0%); and aneurysm remnant, in 10/50 (20.0%) (adequate occlusion in 40/50, 80.0%).CONCLUSIONS:WEBCAST 2 confirms the high safety and efficacy of WEB aneurysm treatment demonstrated in the WEBCAST and French Observatory studies.

Endovascular treatment is now the first-line treatment for ruptured aneurysms.¹ For unruptured aneurysms, no randomized trial has been completed that permits the direct comparison of clipping with endovascular treatment. However, at least in Europe, the tendency is to give priority to endovascular treatment.² Some aneurysms, especially those with a wide-neck, are difficult to treat due to the challenges of stabilizing coils inside the aneurysm sac and avoiding their protrusion into the parent artery. Thus, more complex endovascular techniques have been developed, such as balloon-assisted coiling, stent-assisted coiling, and flow diversion.^3–8Flow disruption is now a well-established procedure for the treatment of wide-neck bifurcation aneurysms.^9–13 Today, it is also used in narrow-neck aneurysms and sidewall aneurysms.¹⁴ The therapy involves the placement of an intrasaccular device that alters the flow inside the aneurysm, inducing intrasaccular thrombosis. Introduced in 2010 in Europe, the Woven EndoBridge (WEB; Sequent Medical, Aliso Viejo, California) is the only intrasaccular device that has been extensively evaluated in the literature with several single- and multicenter, retrospective, and prospective series.^9–21 Good Clinical Practice studies, including the WEB Clinical Assessment of IntraSaccular Aneurysm Therapy (WEBCAST) and the French Observatory studies, have shown a high level of safety with the device.^15–18 Efficacy has to be further evaluated, but 1-year anatomic results in both the WEBCAST and French Observatory studies are encouraging. However, important changes in the device have been introduced across the time, moving from a dual-layer, larger profile version (WEB-DL) to single-layer, lower profile versions (WEB-SL and WEB Single-Layer Spherical [SLS]) and more recently Single-Layer with Enhanced Visualization (EV) obtained by introducing composite wires of nitinol and platinum in the braid itself.The WEBCAST study evaluated the WEB-DL, whereas the French Observatory evaluated the WEB-DL, WEB-SL, and the WEB-SLS.^15–18 In the continuing effort to assess the clinical and anatomic performance of these new devices, it was logical to further evaluate this technique with a series of patients treated exclusively with single-layer (SL, SLS) and Enhanced Visualization devices.     

WEB Treatment of Intracranial Aneurysms: Clinical and Anatomic Results in the French Observatory

BACKGROUND AND PURPOSE:Flow disruption with the WEB device is a new technique for the endovascular treatment of wide-neck bifurcation aneurysms. To obtain precise data regarding the safety and efficacy of this treatment with high-quality methodology, the prospective French Observatory study was conducted. Analysis of these data is presented, including 1-year follow-up.MATERIALS AND METHODS:Patients with bifurcation aneurysms for which WEB treatment was indicated were included in this prospective, multicenter Good Clinical Practice study. Clinical data, including adverse events and clinical status at 1 month and 1 year, were collected and independently analyzed by a medical monitor. An independent core laboratory evaluated the anatomic results at 1 year following the procedure.RESULTS:Ten French neurointerventional centers included 62 patients (39 women), 33–74 years of age (mean, 56.6 ± 9.80 years) with 63 aneurysms. Aneurysm locations were the middle cerebral artery in 32 aneurysms (50.8%), anterior communicating artery in 16 (25.4%), basilar artery in 9 (14.3%), and internal carotid artery terminus in 6 (9.5%). Morbidity and mortality at 1 month were, respectively, 3.2% (2/62 patients) and 0.0% (0/62). Morbidity and mortality (unrelated to the treatment) at 1 year were, respectively, 0.0% (0/59) and 3.4% (2/59 patients). At 1 year, complete occlusion was observed in 30/58 aneurysms (51.7%); neck remnant, in 16/58 aneurysms (27.6%); and aneurysm remnant, in 12/58 aneurysms (20.7%).CONCLUSIONS:This prospective French Observatory study showed very good safety of aneurysm treatment with the WEB, with a high rate of adequate aneurysm occlusion at 1 year (79.3%).

Endovascular treatment is now the first-line therapy for both ruptured and unruptured aneurysms, but aneurysms with a complex anatomy (especially wide-neck aneurysms) are, in some cases, untreatable or difficult to treat with standard coiling.^1,2 Thus, more complex endovascular techniques have been developed, such as balloon-assisted coiling, stent-assisted coiling, and flow diversion.^3–9Flow disruption is a new endovascular approach, which involves placement of an intrasaccular device (Woven EndoBridge [WEB] aneurysm embolization system; Sequent Medical, Aliso Viejo, California), which modifies the blood flow at the level of the neck and induces aneurysmal thrombosis. The WEB was designed to treat wide-neck and bifurcation aneurysms. The device has been progressively developed from a Dual-Layer version (WEB DL) to Single-Layer (WEB SL) and Single-Layer Spherical (WEB SLS) versions. Treatment with the WEB has been evaluated in several retrospective series showing good safety results.^10–13 In addition, midterm and long-term anatomic results have been evaluated in retrospective series showing good stability of the treatment.^14,15To have a more rigorous evaluation of the safety and efficacy, 2 prospective, Good Clinical Practice series were initiated simultaneously in Europe (WEB Clinical Assessment of IntraSaccular Aneurysm Therapy [WEBCAST]) and in France (French Observatory). The short-term (6-month) results of the WEBCAST trial and a comparison of safety between the WEB DL and WEB SL/SLS in the French Observatory were published previously.^16,17 These initial analyses confirmed the good safety and efficacy of the device in the short-term. This article reports the clinical and anatomic results of the French Observatory study with midterm (1-year) follow-up.     

The Woven EndoBridge: a new aneurysm occlusion device

BACKGROUND AND PURPOSE:The WEB device is an intrasaccular ellipsoid braided-wire embolization device designed to provide flow disruption along the aneurysm neck. The purpose of this study was to evaluate, in an in vivo aneurysm model, the acute and chronic performance of the WEB device regarding immediacy, degree, and durability of aneurysm occlusion.MATERIALS AND METHODS:The WEB device was implanted in 24 elastase-induced aneurysms in New Zealand white rabbits and followed for 1, 3, 6, and 12 months (n = 6 at all time points). Degree of intra-aneurysmal flow disruption was graded on a 4-point scale based on DSA within 10 minutes following device implantation. Chronic aneurysm occlusion was rated by using a 3-point scale. All aneurysms were harvested for histologic analysis.RESULTS:Immediate postimplant grade 1 (complete flow cessation) was noted in 7 (29%) of 24 cases. Grade 2 (near-complete flow cessation) was noted in 13 (54%) of 24 cases. At follow-up, complete occlusion was noted in 8 (33%) of 24 cases. Near-complete aneurysm occlusion was noted in 14 (58%) of 24 cases, while incomplete occlusion was noted in 2 (8%) cases. Stable aneurysm occlusion was present in 7 (29%) of 24 cases; progressive occlusion, in 14 (58%); and recanalization, in 3 (13%) cases. Histologic findings included aneurysm cavities filled with organized thrombus with connective tissue across the aneurysm neck.CONCLUSIONS:The WEB device in experimental aneurysms demonstrated promising rates of immediate and long-term aneurysm occlusion.

Recent advances in endovascular aneurysm repair have substantially impacted our understanding of how treated aneurysms heal after embolization. Until recently, the primary focus of most aneurysm devices was on healing within the aneurysm sac. Bare platinum coils, subject to high rates of aneurysm recanalization, were modified to enhance intrasaccular organization. Unfortunately, it has yet to be proved in the clinical setting that most coil modifications perform better than bare platinum coils.^1–10Intraluminal “flow diverters,” comprising tubular braided metallic implants, have shown, in preclinical studies and in early clinical reports, the ability to achieve complete occlusion in a high proportion of aneurysms.^11–20 Excellent occlusion rates after flow-diverter therapy are seen even in large and giant aneurysms, which show recanalization rates of ≥50% after coil embolization.^21,22 The success of these new devices has refocused the attention from the aneurysm dome to the aneurysm neck as the point of relevance in aneurysm treatment. Specifically, achieving a stable construct across the aneurysm neck, irrespective of intra-aneurysmal findings, may be the best predictor of long-term occlusion.Notwithstanding the early promise of intraluminal flow diverters, important shortcomings limit widespread application of these devices. Because of the perceived risk of thromboembolism, patients treated with endoluminal flow diverters are placed on dual antiplatelet therapy. This medical therapy limits use, in most cases, to unruptured aneurysms, given the risk of hemorrhagic complications if patients require external ventricular drainage.²³ Use of these endoluminal devices is further limited in ruptured aneurysms because closure of the aneurysm is delayed by weeks or months after implantation, such that an acutely ruptured aneurysm would not be adequately protected in the short term. Furthermore, the design of the endoluminal devices renders them difficult to use in bifurcation-type aneurysms. Last, use of these devices in the vicinity of eloquent perforating arteries raises concern for stroke.In this report, we detail a new device that mimics the flow-diverting mechanism of the intraluminal flow diverters, yet is placed entirely within the aneurysm cavity. This new intrasaccular device, termed the WEB aneurysm embolization device (Sequent Medical, Aliso Viejo, California), achieves placement of a high-attenuation metallic mesh both along the aneurysm wall and across the neck, which thus functions as an intrasaccular flow diverter. The device is intended as a stand-alone therapy, without adjunctive coils placed into the aneurysm cavity or within the WEB device. Because the WEB device is intrasaccular and presents a metal mesh-filled neck not unlike a coil-packed aneurysm, we anticipate that there will be no need for antiplatelet therapy. Further, the device likely would be amenable for treatment of a broad range of aneurysms, including bifurcation-type morphologies, and does not place adjacent perforating arteries at risk. Last, the WEB device is designed to facilitate acute aneurysm occlusion, rendering it appropriate for use in ruptured aneurysms.The purpose of this study was to evaluate, in an in vivo aneurysm model, the acute and long-term performance of the WEB device regarding immediacy, degree, and durability of aneurysm occlusion.     

WEB Treatment of Ruptured Intracranial Aneurysms

BACKGROUND AND PURPOSE:The Woven EndoBridge (WEB) device was recently introduced for intrasaccular treatment of wide-neck aneurysms without the need for adjunctive support. We present our first experience in using the WEB for small ruptured aneurysms.MATERIALS AND METHODS:During 11 months, 32 of 71 (45%) endovascularly treated acutely ruptured aneurysms were treated with the WEB. The patients were 12 men and 20 women, with a mean age of 61 years (range, 34–84 years). The mean aneurysm size was 4.9 mm, and 14 were ≤4 mm. Of 32 aneurysms, 24 (75%) had a wide neck.RESULTS:All 32 aneurysms were adequately occluded after WEB placement. There were no procedural ruptures and no complications related to the WEB device. No adjunctive stents or balloons were needed. In 3 patients, thromboembolic complications occurred. One patient developed an infarction, and 2 patients were asymptomatic. The procedural complication rate was 3%. Seven patients admitted in poor clinical grade conditions died during hospital admission due to the sequelae of SAH. In 18 patients with angiographic follow-up at 3 months, 16 aneurysms remained adequately occluded. Two aneurysms showed slight compression of the WEB without reopening. Clinical follow-up in the 25 patients who survived the hospital admission period revealed mRS 1–2 in 24 and mRS 4 in 1. There were no rebleeds from the ruptured aneurysms during follow-up.CONCLUSIONS:WEB treatment of small ruptured aneurysms was safe and effective without the need for anticoagulation, adjunctive stents, or balloons. Our preliminary experience indicates that the WEB may be a valuable alternative to coils in the treatment of acutely ruptured aneurysms.

Endovascular treatment with coils of wide-neck intracranial aneurysms remains a technical challenge. To prevent extrusion of coils from the aneurysmal sac, a temporary protection balloon or a stent can be used. However, this makes the procedure more complicated with a higher chance of complications.^1,2 With the use of stents, periprocedural dual-antiplatelet therapy is required and has to be prolonged for 3–6 months. With this anticoagulation, stent-assisted coiling in ruptured aneurysms has a higher inherent risk for early rebleed or hemorrhage in the postoperative period.³Recently, an intrasaccular flow disruptor, Woven EndoBridge (WEB; Sequent Medical, Aliso Viejo, California), has been developed. The primary use of the WEB is the treatment of bifurcation or wide-neck aneurysms without the need of adjunctive devices. There is a growing body of literature on the use of the WEB device with excellent safety and efficacy profiles. Most of the published series comprised wide-necked, unruptured aneurysms.^4–16 When the WEB became available in our hospital, our initial results in unruptured aneurysms were encouraging, and we decided to expand the indications to both ruptured and unruptured aneurysms suitable for accommodating a WEB device, regardless of neck size. Our intention was to avoid using stents or balloons in ruptured aneurysms. In this article, we present our first results of the use of the WEB device in small ruptured aneurysms.     

One-Year Angiographic Follow-Up after WEB-SL Endovascular Treatment of Wide-Neck Bifurcation Intracranial Aneurysms

BACKGROUND AND PURPOSE:Endovascular coiling of wide-neck intracranial aneurysms is associated with low rates of initial angiographic occlusion and high rates of recurrence. The WEB intrasaccular device has been developed specifically for this indication. To date, there has been no report of the long-term follow-up of a series of patients with aneurysms treated with this type of device, to our knowledge. Our aim was to evaluate a 1-year follow-up of angiographic results in a prospective single-center series of patients treated with the WEB-Single-Layer (SL) device.MATERIALS AND METHODS:All patients treated with the WEB-SL device in our center between August 2013 and May 2014 were prospectively included. One-year angiographic outcomes were assessed. Results at follow-up were graded as complete occlusion, neck remnant, or residual aneurysm.RESULTS:Eight patients with 8 unruptured wide-neck aneurysms were enrolled in this study. Average dome width was 7.5 mm (range, 5.4–10.7 mm), and average neck size was 4.9 mm (range, 2.6–6.5 mm). One-year angiographic follow-up obtained in all aneurysms included 1 complete aneurysm occlusion (12.5%), 6 neck remnants (75%), and 1 aneurysm remnant (12.5%). Of 8 aneurysms, worsening of aneurysm occlusion was observed in 2 (25%) by compression of the WEB device. There was no angiographic recurrence of initially totally occluded aneurysms. No bleeding was observed during the follow-up period.CONCLUSIONS:Endovascular therapy of intracranial aneurysms with the WEB-SL device allows treatment of wide-neck aneurysms with a high rate of neck remnant at 1 year, at least partially explained by WEB compression. Initial size selection and technologic improvements could be an option for optimization of aneurysm occlusion in WEB-SL treatment.

The WEB aneurysm embolization system (Sequent Medical, Aliso Viejo, California) is an intrasaccular braided device specifically developed for endovascular treatment of wide-neck intracranial aneurysms with the goal of disrupting flow at the aneurysm neck and promoting aneurysmal thrombosis without the need for reconstruction of the entire parent artery segment with a stent. Several types of WEB devices are currently available¹: the WEB-Dual-Layer (DL), which is made of 2 layers held together and creating 2 compartments, and the WEB-Single-Layer (SL), which is a single-layer device creating only 1 compartment. Only a few studies on the treatment of intracranial aneurysms by using the WEB-DL have been published,^2–5 and to date, only a single published article on aneurysms treated with WEB-SL reported a series including any anatomic follow-up.⁶ We recently published the 6-month clinical and anatomic outcomes of WEB-SL endovascular treatment.⁷The purpose of this study was to evaluate the 1-year angiographic results of patients managed with the WEB-SL device in a prospective single-center series.     

Endovascular Treatment of Intracranial Aneurysms with the WEB Device: A Systematic Review of Clinical Outcomes

BACKGROUND AND PURPOSE:Despite the improvement in technology, endovascular treatment of bifurcation intracranial wide-neck aneurysms remains challenging, mainly due to the difficulty of maintaining coils within the aneurysm sac without compromising the patency of bifurcation arteries. The Woven EndoBridge (WEB) device is a recent intrasaccular braided device specifically dedicated to treating such aneurysms with a wide neck by disrupting the flow in the aneurysmal neck and promoting progressive aneurysmal thrombosis.MATERIALS AND METHODS:Using several health data bases, we conducted a systematic review of all published studies of WEB endovascular treatment in intracranial aneurysms from 2010 onward to evaluate its efficacy and safety profile.RESULTS:The literature search identified 6 relevant studies (7 articles) including wide-neck bifurcation aneurysms in ≥80% of cases. Clinical data supporting the efficacy and safety of the WEB are limited to noncomparative cohort studies with large heterogeneity from a methodologic standpoint. The WEB deployment was feasible with a success rate of 93%–100%. Permanent morbidity (mRS of >1 at last follow-up) and mortality were measured at 2.2%–6.7% and 0%–17%, respectively. The adequate occlusion rate (total occlusion or neck remnant) varied between 65% and 85.4% at midterm follow-up (range, 3.3–27.4 months).CONCLUSIONS:Endovascular treatment of bifurcation wide-neck aneurysms with the WEB device is feasible and allows an acceptably adequate aneurysm occlusion rate; however, the rate of neck remnants is not negligible. The WEB device needs further clinical and anatomic evaluation with long-term prospective studies, especially of the risk of WEB compression. Prospective controlled studies should be encouraged.

With the emergence of detachable coils and results of the International Subarachnoid Aneurysm Trial and Barrow Ruptured Aneurysm Trial,^1,2 endovascular coiling has become the first-line option for ruptured intracranial aneurysms. It is also a widely accepted option for unruptured aneurysms that are anatomically suitable for endovascular approaches.³ However, coiling of large and wide-neck intracranial aneurysms is associated with low initial complete obliteration, a high incidence of recanalization (up to 20% at 12 months), and a 10% rate of retreatment.⁴ Promising technologies like flow-diverter stents have the potential to overcome some of the limitations of standard coiling for sidewall aneurysms,^5–7 but the management of large wide-neck bifurcation aneurysms remains challenging. Balloon and stent-assisted techniques have widened the indications for endovascular treatment of aneurysms with a wide neck and/or unfavorable anatomy that were otherwise unsuitable for coiling.^8–10 However, endovascular treatment of such complex intracranial aneurysms requires the use of complex endovascular techniques with double-stent placement in Y and X configurations. Bartolini et al¹¹ suggested that Y and X stent-assisted coiling was associated with a high rate of complications, 10% procedure-related permanent morbidity, and 1% mortality rate.In this context, a new endovascular device, the intrasaccular flow disruptor Woven EndoBridge (WEB; Sequent Medical, Aliso Viejo, California), specifically designed to treat wide-neck bifurcation intracranial aneurysms, has emerged in the past 5 years.^12–14 There is an emerging body of literature on the use of the WEB device, but to our knowledge, no study has specifically reviewed the evidence on its use. We, therefore, performed a literature review of this technique in the management of wide-neck bifurcation intracranial aneurysms. Our specific aims were to evaluate its feasibility, safety, and effectiveness to finally discuss its place in the endovascular treatment of bifurcation intracranial aneurysms.     

WEB Treatment of Intracranial Aneurysms: Feasibility,Complications, and 1-Month Safety Results with the WEB DL and WEB SL/SLS in the French Observatory

BACKGROUND AND PURPOSE:Safety analyses in the French Observatory have shown that treatment of intracranial aneurysms by using flow disruption with the Woven EndoBridge Device (WEB) is safe, with low morbidity and no mortality. The objective of this study was to analyze treatment feasibility, complications, and safety results in patients treated with the Woven EndoBridge Device Dual-Layer (WEB DL) and Woven EndoBridge Device Single-Layer/Single-Layer Sphere (WEB SL/SLS) in the French Observatory.MATERIALS AND METHODS:Patients with bifurcation aneurysms were included in this prospective, multicenter good clinical practices study. A medical monitor independently analyzed procedural and clinical data. The study started with the WEB DL, and secondarily, the WEB SL/SLS was authorized in the study.RESULTS:Between November 2012 and January 2014, 10 French centers included 62 patients with 63 aneurysms. Thirty patients with 31 aneurysms were treated with the WEB DL, and 32 patients with 32 aneurysms, with the WEB SL/SLS. The percentage of anterior communicating artery aneurysms treated with WEB SL/SLS was significantly higher (37.5%) compared with WEB DL (12.9%) (P = .04). The WEB SL/SLS was more frequently used in aneurysms of <10 mm than the WEB DL (respectively, 96.9% and 67.7%; P = .002). Morbidity was similar in both groups (WEB DL, 3.3%; WEB SL/SLS, 3.1%), and mortality was 0.0% in both groups.CONCLUSIONS:This comparative study shows increased use of WEB treatment in ruptured, small, and anterior communicating artery aneurysms when using WEB SL/SLS. There was a trend toward fewer thromboembolic complications with the WEB SL/SLS. With both the WEB DL and WEB SL/SLS, the treatment was safe, with low morbidity and no mortality.

Endovascular treatment is the preferred therapeutic option for ruptured aneurysms that are anatomically suitable for endovascular coil treatment, supported by randomized studies, especially in locations less suitable for surgery.^1,2 It also has an important place in the management of unruptured aneurysms that are judged appropriate for treatment.³ Complex aneurysms (fusiform, wide-neck, large, or giant) are often untreatable or difficult to treat with standard coiling. For these complex cases, endovascular techniques such as balloon-assisted coiling, stent-assisted coiling, or flow diversion have been used with good results.^4–9Flow disruption is a new endovascular approach, which involves placement of a Woven EndoBridge Device (WEB; Sequent Medical, Aliso Viejo, California), which modifies the blood flow at the level of the neck and induces intra-aneurysmal thrombosis. The WEB was designed initially to treat wide-neck and bifurcation aneurysms. The initial clinical results have shown that treatment is feasible with a low level of complications, low morbidity, and no mortality.^10–14 The device has been progressively developed from a dual-layer version (WEB Dual-Layer [DL] aneurysm embolization system; Sequent Medical) to single-layer versions (WEB Single-Layer [SL] and WEB Single-Layer Sphere [SLS]).The French Observatory is a prospective, multicenter observational study of consecutive cases, with independent monitoring, across 10 French centers.It has 2 major objectives:

1. To carefully evaluate the safety of this treatment with an independent assessment of all adverse events and morbidity/mortality.
2. To evaluate the efficacy of this treatment at 12 and 24 months with independent core lab adjudication.

Patients treated with both WEB DL and WEB SL/SLS were included in the French Observatory. The present analysis reports the feasibility of treatment, adverse events, and morbidity/mortality at 1 month in patients treated with WEB DL and WEB SL/SLS.     

Endovascular Treatment of Small and Very Small Intracranial Aneurysms with the Woven EndoBridge Device

BACKGROUND AND PURPOSE:The Woven EndoBridge has proved to be a safe and effective treatment, especially for wide-neck intracranial aneurysms. The recent fifth-generation Woven EndoBridge came with smaller devices. The purpose of this study was to assess the safety and efficiency of Woven EndoBridge treatment of small and very small aneurysms.MATERIALS AND METHODS:Between September 2017 and March 2020, all consecutive patients treated with a 3- or 3.5 mm-width Woven EndoBridge device were included in this retrospective intention-to-treat study. Clinical and radiologic findings were evaluated at immediate and last-available follow-up. Angiographic outcome was assessed by an external expert reader.RESULTS:One hundred twenty-eight aneurysms were treated with a fifth-generation Woven EndoBridge device including 29 with a width of ≤3.5 mm. Ten aneurysms were ruptured (34%). In 3 cases (10%), Woven EndoBridge treatment could not be performed because the aneurysm was still too small for the smallest available Woven EndoBridge device and another endovascular strategy was chosen. The median follow-up time was 11.2 months. Complete and adequate occlusion was obtained in 71% and 90% of the treated aneurysms, respectively. Retreatment was needed in 2 cases (10%). Symptomatic ischemic complications leading to transient neurologic deficits occurred in 2 cases (7%) (1 procedure-related and 1 device-related) but with full spontaneous recovery at discharge.CONCLUSIONS:The fifth-generation Woven EndoBridge device seems to be a safe and technically feasible treatment for both ruptured and unruptured small and very small intracranial aneurysms, with satisfactory occlusion rates on midterm follow-up. However, further study is needed to evaluate longer-term efficiency.

Since the publications of the results of the International Subarachnoid Aneurysm Trial (ISAT), in many centers, endovascular therapy has become the first-line treatment for intracranial aneurysms.^1,2 With an annual rupture rate of 0.36% per year, the treatment of small, unruptured, intracranial aneurysms remains disputable.³ However, independent predictors of rupture such as a history of subarachnoid hemorrhage, active smoking, location on the anterior communicating artery, and aneurysm multiplicity were identified, providing selection criteria for potential treatment. ^4-7The treatment of small and very small aneurysms is often challenging, especially for ruptured cases, in which therapeutic options are limited.^8-10 Conceived as an intrasaccular flow-disruption device, the Woven EndoBridge aneurysm embolization system (WEB; MicroVention) has proved to be a safe and effective treatment for bifurcation aneurysms.^11-14 The absence of systematic use of antiplatelet therapy in a hemorrhagic context makes the WEB therapy particularly interesting for ruptured wide-neck aneurysms.^15-17Since 2010, the device progressively evolved from an initial double-layer version to single-layer (SL-WEB) and single-layer spherical versions. Recently, the fifth-generation WEBs became available outside the United States,¹⁸ compatible with a new and smaller delivery catheter (VIA 17; MicroVention), facilitating the treatment of smaller and more distal aneurysms. The changes in the braiding design allowed the development of smaller devices (3- and 3.5-mm width).The WEB device has been evaluated in many Good clinical practice (GCP) studies, but the smaller fifth-generation devices were not included at that time. ^11,19,20 The purpose of this study was to report the follow-up results of ruptured and unruptured small and very small intracranial aneurysms treated using the new, smaller fifth-generation WEB devices.     

Efficacy and Safety of the Woven EndoBridge (WEB) Device for the Treatment of Intracranial Aneurysms: A Systematic Review and Meta-Analysis

BACKGROUND AND PURPOSE:Intrasaccular flow diverters are increasingly being used in the treatment of wide-neck and bifurcation aneurysms. We performed a systematic review and meta-analysis of existing literature on the Woven EndoBridge device in the treatment of intracranial aneurysms.MATERIALS AND METHODS:A comprehensive literature search was performed through October 1, 2015. We extracted information on baseline aneurysm and patient characteristics. Outcomes studied included immediate and midterm (>3 month) angiographic outcomes (complete occlusion as well as adequate occlusion, defined as complete occlusion or neck remnant), aneurysm retreatment, intraoperative rupture, perioperative morbidity and mortality, thromboembolic complications, and treatment failure. Meta-analysis was performed by using the random-effects model.RESULTS:Fifteen uncontrolled series were included in this analysis, including 565 patients with 588 aneurysms, of which 127 were ruptured. Initial complete and adequate occlusion rates were 27% (95% CI, 15%–39%) and 59% (95% CI, 39%–78%), respectively. Midterm complete and adequate occlusion rates after a median of 7 months were 39% (95% CI, 26%–52%) and 85% (95% CI, 78%–91%), respectively. Perioperative morbidity and mortality rates were 4% (95% CI, 1%–8%) and 1% (95% CI, 0%–2%), respectively. Midterm adequate occlusion rates for ruptured aneurysms were 85% (95% CI, 67%–98%), compared with 84% (95% CI, 72%–94%) for unruptured aneurysms (P = .89). Patients with ruptured aneurysm had similar rates of perioperative morbidity to patients with unruptured aneurysm (2%; 95% CI, 0%–26% versus 2%; 95% CI, 0%–6%, respectively; P = .35).CONCLUSIONS:Early evidence derived from uncontrolled studies suggests that Woven EndoBridge treatment has a good safety profile and promising rates of adequate occlusion, especially given the complexity of aneurysms treated. Further prospective clinical trials are needed to confirm these results and better define the risks and benefits of use of the Woven EndoBridge device in treating wide-neck and wide-neck bifurcation aneurysms.

With the advent of stent-assisted and balloon-assisted coiling, wide-neck and wide-neck bifurcation intracranial aneurysms are increasingly treated with endovascular techniques. Both stent-assisted and balloon-assisted coiling have been shown safe and effective in treating these aneurysms by allowing for increased packing and lower rates of parent artery occlusion compared with conventional coiling alone.^1–7 However, because of less than satisfactory occlusion rates with coil embolization of wide-neck and wide-neck bifurcation aneurysms, there has been a push toward treating these lesions with intrasaccular and intraluminal flow diverters.The Woven EndoBridge (WEB; Sequent Medical, Aliso Viejo, California) is a nitinol braided-wire intravascular device designed to disrupt blood flow at the aneurysmal neck. This device is specifically designed for the treatment of wide-neck bifurcation aneurysms.^8,9 To date, several case series have demonstrated that the WEB device is both safe and effective in treatment of wide-neck and wide-neck bifurcation aneurysms.^10–13 We present the results of a systematic review and meta-analysis examining outcomes of endovascular treatment of wide-neck and wide-neck bifurcation aneurysms with the WEB device. The aim of our study was to assess both angiographic and clinical outcomes.     

Silk Flow-Diverter Stent for the Treatment of Intracranial Aneurysms: A Series of 58 Patients with Emphasis on Long-Term Results

BACKGROUND AND PURPOSE:The Silk flow-diverter stent is increasingly used to treat complex intracranial aneurysms including wide-neck, fusiform aneurysms. Sparse data are available concerning long-term results of this technique. We report our 5-year experience with Silk stent treatment of intracranial aneurysms.MATERIALS AND METHODS:A retrospective review of our prospectively maintained database identified all patients treated by the Silk stent in 2 institutions. Clinical charts, procedural data, and angiographic results were reviewed.RESULTS:Between July 2009 and May 2014, we identified 58 patients with 70 intracranial aneurysms. Endovascular treatment was successful in 93% of patients with 32 treated with the first-generation Silk stent and 26 with the new Silk+ stent. Mean follow-up in 47 patients was 22 months. Despite an 11% delayed complication rate, overall permanent neurologic morbidity was 5.5%. All complications were seen with the first-generation Silk stent. There was no procedure-related mortality. Long-term anatomic results showed 73% with complete occlusion, 16% with neck remnants, and 11% with incomplete occlusion. No recanalization or retreatment was performed. The midterm intrastent stenosis rate was 57%, of which 60% improved or disappeared, 28% were stable, and 12% led to vessel occlusion. Seventy-four percent of stenosis and all vessel occlusions occurred with the first-generation Silk stent.CONCLUSIONS:Endovascular treatment of complex intracranial aneurysms with the Silk stent is an effective therapeutic option. Despite a high rate of delayed complications with the first-generation stents, the current Silk+ stent appears safer. This treatment achieves a high rate of adequate and stable occlusion at long-term follow-up.

Endovascular treatment is now the first-intention treatment for both ruptured and unruptured intracranial aneurysms.^1–4 However, endovascular treatment of complex intracranial aneurysms (wide-neck and fusiform) remains technically challenging. On the other hand, aneurysm coil recanalization is an important issue in endovascular therapy, with approximately 20% of coiled aneurysms recanalized and 10% retreated.⁵ As previously shown, wide-neck aneurysms are highly prone to recanalization.⁶These relative limitations of standard coiling have contributed to the development of new endovascular approaches, including balloon-assisted coiling, stent-assisted coiling, flow diversion, and flow disruption. Flow-diverter stents have been developed, and they offer the potential of aneurysm occlusion related to flow disruption. Recently, several flow-diverter stents, such as the Silk flow diverter (Balt Extrusion, Montmorency, France), have been released, and short- and midterm results have been published.^7–15 Notwithstanding the early promise of these devices, important shortcomings have been reported. First, delayed complications, either hemorrhagic or thromboembolic, are not uncommon; second, the flow-diverter stent tolerance might be considered poor because of the relatively high rates of intrastent stenosis and parent artery occlusion (PAO) during follow-up.^7–15 To the best of our knowledge, sparse data are available about the long-term results of this technique, including stability of aneurysm occlusion and stent tolerance. These data are mandatory to define the place of flow-diverter stents in the therapeutic armamentarium of intracranial aneurysms. Therefore, the aim of our study was to report our 5-year experience with Silk stent treatment of intracranial aneurysms with an emphasis on long-term results.     

Packing Density Necessary to Reach a High Complete Occlusion Rate in Circumferential Unruptured Intracranial Aneurysms Treated with Stent-Assisted Coil Embolization

BACKGROUND AND PURPOSE:This study is a homogeneous series of circumferential unruptured intracranial aneurysms with large necks treated with stent-assisted coil embolization. Our purpose was to demonstrate which value of packing density is required to produce a durable occlusion.MATERIALS AND METHODS:We retrospectively evaluated all patients with unruptured intracranial aneurysms who were treated with stent-assisted coil embolization having late angiographic control between 2004 and 2014, in a single large cerebrovascular referral center. To calculate the packing density, aneurysm volume, and coil volume, we used an on-line system.RESULTS:In 49 circumferential unruptured intracranial aneurysms treated with stent-assisted coil embolization, 38.7% (n = 19) had complete occlusion in the immediate control. Of those with incomplete occlusion, 80% (n = 24) progressed to complete occlusion in the late angiographic follow-up. At late angiographic control, 87.7% (n = 43) of aneurysms were completely occluded. All aneurysms with a packing density of ≥19% were completely occluded. Packing density was the only statistically significant predictor of complete occlusion. None of the aneurysms with complete occlusion at immediate control or at late angiographic control had recurrence.CONCLUSIONS:In circumferential aneurysms treated with stent-assisted coil embolization, packing density is the main predictor of complete occlusion. In this type of aneurysm, a packing density of ≥19% was enough to reach complete occlusion; knowing this is important to avoid higher packing densities that have more risk.

Unruptured intracranial aneurysms (UIAs) are present in 3% of the adult population and are increasingly detected due to more frequent use of noninvasive angiographic diagnostic imaging.^1–3Endovascular coiling for the treatment of intracranial aneurysms was first introduced into clinical use in 1990, and since then, the greatest concern has been the high recanalization rate, recently estimated to be approximately 20%.^4,5 This occurs more often in large-neck aneurysms,⁶ which are currently treated with stent-assisted coil embolization (SACE).In unassisted coil embolization, higher packing density (PD) rates are correlated with lower recanalization rates.^7–10 It is likely that in SACE treatment, the packing density necessary to reach a stable complete occlusion is lower, but there is no homogeneous study to confirm that possibility, to our knowledge.The purpose of this study was to demonstrate which value of PD is likely to produce durable occlusion in a homogeneous series of circumferential, large-neck UIAs treated with SACE in a single cerebrovascular referral center.     

Differences in the Angiographic Evaluation of Coiled Cerebral Aneurysms between a Core Laboratory Reader and Operators: Results of the Cerecyte Coil Trial

BACKGROUND AND PURPOSE:Independent evaluation of angiographic images is becoming widely applied in the assessment of treatment outcomes of cerebral aneurysms. In the current study, we assessed the agreement between an independent core laboratory and the operators regarding angiographic appearance in a recent randomized, controlled trial.MATERIALS AND METHODS:Data were derived from the Cerecyte Coil Trial. Angiographic images of each coiled aneurysm, taken immediately after embolization and at 5- to 7-month follow-up, were evaluated by the operator at the treating center and by an independent neuroradiologist at the core laboratory. For the purpose of this study, images were interpreted on a 3-point scale to provide uniformity for analysis; grade 1: complete occlusion, grade 2: neck remnant; and grade 3: sac filling. “Unfavorable angiographic appearance” was defined as grade 3 at follow-up or interval worsening of grade between the 2 time points.RESULTS:The study included 434 aneurysms. Immediately after embolization, grade 3 was reported by operators in 39 (9%) compared with 52 (12%) by the core laboratory (P = .159). On follow-up, grade 3 was reported by operators in 44 (10%) compared with 81 (19%) by the core laboratory (P < .0001). Overall, operators noted unfavorable angiographic appearance in 78 (18%) compared with 134 (31%) by the core laboratory (P < .0001). At every time point, agreement between the core laboratory and the operators was slight.CONCLUSIONS:Unfavorable angiographic appearance was noted almost twice as frequently by an independent core laboratory as compared with the operators. Planning of trials and interpretation of published studies should be done with careful attention to the mode of angiographic appearance interpretation.

Angiographic imaging represents the principal metric for evaluating endovascular treatment of cerebral aneurysms and comparing the efficacy of different coil types. The relationship between complete or stable aneurysm occlusion and incomplete occlusion and the risk of delayed aneurysm re-bleeding remains uncertain. Angiographic results are also used to decide on whether further treatment is considered. Treatment success and indications for further management, including the possibility of an additional intervention, are highly dependent on angiographic appearance in the belief that patients with incomplete occlusion are at risk of hemorrhage, though the size of this risk is unknown. Most previous literature included assessments of angiographic appearance on the basis of readings performed in the treating center(s).^1–3 However, other investigators,^4–11 especially in the setting of randomized, controlled trials,^9–11 have used an independent core laboratory for angiographic assessment. Independent core laboratories represent a centralized approach and can provide a standard operating procedure for imaging review. In this respect, they are used to provide a more objective assessment within a trial setting than may be possible at treating centers. This suggested objectivity may also result from the core laboratory being blinded to treatment settings, using the same prespecified systematic reviewing protocols, and usually consisting of more experienced reviewers. On the other hand, operators, being aware of the details of the patient status and the procedure, may have a hands-on sense of “success” when considering the risk-benefit ratio of adding more coils to the treated aneurysm. Also, there is currently no study addressing the degree of objectivity of operators judging their own procedural results at the end of prolonged risk procedures.Reported angiographic appearance after endovascular treatment has varied widely in previous studies.^12–15 Many factors are known to influence angiographic appearance, including aneurysm size, neck diameter, initial rupture status, and follow-up duration.^10,16–18 However, the influence of core laboratory interpretation on outcomes for research purposes, compared with operator evaluations at the treating centers, remains poorly studied.^19,20 In the current study, we assessed the agreement between an independent core laboratory and the operators at the treating centers regarding angiographic outcomes in a recent randomized, controlled trial.     

WEB Treatment of Ruptured Intracranial Aneurysms: A Single-Center Cohort of 100 Patients

BACKGROUND AND PURPOSE:The Woven EndoBridge device was recently introduced for the intrasaccular treatment of wide-neck aneurysms without the need for adjunctive devices. We present our results of the primary treatment of ruptured aneurysms with the Woven EndoBridge regardless of location or neck size.MATERIALS AND METHODS:Between February 2015 and April 2017, 100 ruptured aneurysms were selectively treated with the Woven EndoBridge. No supporting stents or balloons were used. There were 71 women treated (mean patient age, 59 years; median age, 60 years; range, 23–82 years).RESULTS:The mean aneurysm size was 5.6 mm (range, 3–13 mm), and 42 aneurysms were ≤4 mm. Sixty-six aneurysms (66%) had a wide neck, defined as ≥4 mm or a dome-neck ratio ≤1.5. There was 1 procedural rupture without sequelae. In 9 patients (9%), thromboembolic complications occurred. One poor grade patient died; neurologic deficits remained in 3. Overall treatment-related morbidity-mortality was 4% (4 of 100; 95% CI, 1.2%–10.2%).Two of 100 aneurysms were initially incompletely occluded and were additionally treated early after initial intervention. Of 80 eligible patients, 74 (93%) had 3-month angiographic follow-up. Fifty-four aneurysms (73%) were completely occluded, 17 (23%) had a small neck remnant, and 3 (4%) were incompletely occluded. One patient was additionally treated with a second Woven EndoBridge, and in 2 patients, additional treatment is scheduled. The overall reopening/retreatment rate was 6.8% (5 of 74; 95% CI, 2.6%–15.2%). There were no rebleeds during follow-up.CONCLUSIONS:Treatment of small ruptured aneurysms with the Woven EndoBridge was safe and effective. The Woven EndoBridge proved to be a valuable alternative to coils without the need for stents or balloons.

Endovascular treatment of wide-neck intracranial aneurysms with coils mostly requires the use of a temporary protection balloon or a stent. However, this makes the procedure more complicated with a higher chance of complications.^1–4 With stents, periprocedural dual antiplatelet therapy is required and has to be prolonged for 3–6 months. With this antiaggregation regimen, stent-assisted coiling in ruptured aneurysms has a higher inherent risk for early rebleed or hemorrhage in the postoperative period. Despite antiaggregation, thromboembolic complications still occur.⁵Recently, the intrasaccular flow disruptor Woven EndoBridge (WEB; Sequent Medical, Aliso Viejo, California) device has been developed, primarily for the treatment of (bifurcation) wide-neck aneurysms without the need for adjunctive devices. The first clinical results of the WEB device show good safety and efficacy profiles. Most of the published series comprised wide-neck, unruptured aneurysms.^6–24In a previous publication, we presented our first results of the use of the WEB for all ruptured aneurysms suitable for the device, regardless of location or neck size.²⁵ Our intention was to avoid stents in the treatment of ruptured aneurysms. Our strategy was to treat ruptured wide-neck aneurysms with the WEB or, when WEB placement was not possible, with coiling or surgery. In this study, we present the results of this treatment strategy with an extended cohort of 100 patients with ruptured aneurysms treated with the WEB.     

Flow Diversion in Ruptured Intracranial Aneurysms: A Meta-Analysis

BACKGROUND:Flow diversion is now an established technique to treat unruptured intracranial aneurysms not readily amenable to endovascular coil embolization or open microsurgical occlusion. The role of flow-diverting devices in treating ruptured aneurysms is less clear.PURPOSE:To estimate rates of angiographic occlusion and good clinical outcome in patients with ruptured intracranial aneurysms treated with flow-diverting devices.DATA SOURCES:Systematic review of Ovid MEDLINE, PubMed, Cochrane databases, and EMBASE from inception to December 2015 for articles that included ruptured aneurysms treated with flow diversion.STUDY SELECTION:One hundred seventy-two records were screened, of which 20 articles contained sufficient patient and outcome data for inclusion.DATA ANALYSIS:Clinical and radiologic characteristics, procedural details, and outcomes were extracted from these reports. Aggregated occlusion rates and clinical outcomes were analyzed by using the Fisher exact test (statistical significance, α = .05).DATA SYNTHESIS:Complete occlusion of the aneurysm was achieved in 90% of patients, and favorable clinical outcome was attained in 81%. Aneurysm size greater than 7 mm was associated with less favorable clinical outcomes (P = .027). Aneurysm size greater than 2 cm was associated with a greater risk of rerupture after treatment (P < .001).LIMITATIONS:Observational studies and case reports may be affected by reporting bias.CONCLUSIONS:Although not recommended as a first-line treatment, the use of flow diverters to treat ruptured intracranial aneurysms may allow high rates of angiographic occlusion and good clinical outcome in carefully selected patients. Aneurysm size contributes to treatment risk because the rerupture rate following treatment is higher for aneurysms larger than 2 cm.

Endovascular treatment of intracranial aneurysms with detachable coils was first described in 1991¹ and has since become an established method of aneurysm treatment. The International Study of Unruptured Intracranial Aneurysms² and Analysis of Treatment by Endovascular Approach of Nonruptured Aneurysms (ATENA)³ demonstrated the effectiveness and relative safety of endovascular coiling for unruptured aneurysms. Similarly, the International Subarachnoid Aneurysm Trial (ISAT), the Barrow Ruptured Aneurysm Trial, and other trials^4–7 have demonstrated the effectiveness and relative safety of endovascular coiling in ruptured aneurysms.In recent years, flow diverters (FDs) have emerged as a new endovascular treatment option for intracranial aneurysms. FDs are a reconstructive treatment in which altered flow within an aneurysm induces gradual remodeling and eventual thrombosis of the aneurysm. Several studies have demonstrated good safety and efficacy of FDs for the treatment of unruptured intracranial aneurysms,^8–17 though the safe use of these devices requires the use of dual antiplatelet therapy.^18–20Understandably, the need for antiplatelet medications and the delayed nature of aneurysm thrombosis have tempered enthusiasm for using FDs for ruptured aneurysms. Nevertheless, several reports have described the use of FDs to treat recently ruptured aneurysms, particularly those that are difficult to treat by other endovascular or open microsurgical techniques.In this meta-analysis, we review the outcomes associated with the use of FDs for the treatment of ruptured intracranial aneurysms. Specifically, we review aneurysm characteristics and endovascular treatment strategies in relation to the rates of angiographic occlusion and good clinical outcome, with the overall goal of guiding FD use in ruptured aneurysms when other treatment options are not viable.     

WEB Intrasaccular Flow Disruptor—Prospective,Multicenter Experience in 83 Patients with 85 Aneurysms

BACKGROUND AND PURPOSE:The safety and efficacy of WEB flow disruption have been analyzed in small, retrospective series. The object of this study was to evaluate the safety and efficacy of WEB flow disruption in a large, multicenter, prospectively collected population.MATERIALS AND METHODS:Data from all patients treated with the WEB-DL device between June 2011 and October 2013 in 11 French neurointerventional centers were prospectively collected and retrospectively analyzed. Complications occurring during and after treatment were analyzed as well as morbidity and mortality at 1 month. Aneurysm occlusion status at the last follow-up was analyzed.RESULTS:Eighty-three patients with 85 aneurysms were included in this series. Technical success was achieved in 77 patients with 79 aneurysms (92.9%). Periprocedural complications were observed in 9 patients (10.8%), leading to permanent neurologic deficits in 3 (3.9%). Morbidity and mortality at 1 month were 1.3% and 0.0%, respectively. Angiographic follow-up was performed for 65/79 aneurysms (82.3%) 3–24 months after treatment (mean, 5.3 months). Complete aneurysm occlusion was observed in 37/65 aneurysms (56.9%); neck remnant, in 23/65 (35.4%); and aneurysm remnant, in 5/65 (7.7%).CONCLUSIONS:In this large prospective series of patients, WEB flow disruption was a safe and efficient technique.

Endovascular treatment is now the first therapeutic option for ruptured aneurysms and is important in the treatment of unruptured aneurysms.^1–3 Aneurysms with a complex anatomy (fusiform, wide-neck, large, or giant) are in some cases untreatable or difficult to treat with standard coiling. For these cases, endovascular techniques such as balloon-assisted coiling, stent-assisted coiling, or flow diversion have been used with good results.^4–9The Woven Endoluminal Bridge–Dual Layer (WEB-DL; Sequent Medical, Aliso Viejo, California) is an intra-aneurysmal flow-disruption device, developed to modify the blood flow at the aneurysm neck. Preliminary clinical experience with the WEB has shown the clinical utility of this treatment in wide-neck bifurcation aneurysms. Several preliminary, small, retrospective series have shown good feasibility of the treatment, with a limited number of complications, low morbidity, and no mortality.^10–13 However, because these series were small and conducted in highly specialized centers with a careful selection of cases, there was a need for a safety analysis in a larger series of patients treated in several neurointerventional units.Regarding the efficacy of the method, these preliminary series have also shown good anatomic results but with a relatively high percentage of neck remnants (33.3%–56.7%).^10,12 Further analysis demonstrated that some of the neck remnants were, in fact, due to the opacification of the proximal recess of the WEB device.¹³ This proximal recess opacification has proved stable at midterm follow-up in a recent retrospective series that has also demonstrated good anatomic results and stability of aneurysm obliteration at midterm follow-up.¹³The first patient treated with the WEB-DL device in France was in June 2011. Since this initial case, all further consecutive cases were prospectively included in a data base. The retrospective analysis of the patients treated between June 2011 and October 2013 is presented in this article.