Should indications for WEB aneurysm treatment be enlarged? Report of a series of 20 patients with aneurysms in "atypical" locations for WEB treatment.

BACKGROUND AND PURPOSE: Flow disruption with the WEB device is an innovative technique for the endovascular treatment of wide neck bifurcation aneurysms. Good clinical practice trials have shown high safety of this treatment with good efficacy. Technical developments (single layer devices and smaller microcatheters) facilitate the treatment, potentially leading to enlargement of indications. This series is collecting aneurysms in "atypical" locations for WEB treatment and analyzing safety and efficacy of this treatment. MATERIALS AND METHODS: In each participating center, patients with aneurysms treated with WEB were prospectively included in a local database. Patients treated for aneurysms in "atypical" locations were extracted. Patient and aneurysm characteristics, intraoperative complications, and anatomical results at the end of the procedure and at last follow-up were collected and analyzed. RESULTS: Five French neurointerventional centers included 20 patients with 20 aneurysms in "atypical" locations for WEB treatment treated with WEB. Aneurysm locations were ICA carotid-ophthalmic in 9 aneurysms (45.0%), ICA posterior communicating in 4 (20.0%), Pericallosal artery in 5 (25.0%), and basilar artery between P1 and superior cerebellar artery in 2 (10.0%). There were no complications (thromboembolic or intraoperative rupture) in this series. At follow-up (mean: 7.4 months), adequate occlusion was obtained in 100.0% of aneurysms. CONCLUSIONS: This series confirms that it is possible to enlarge indications of WEB treatment to "atypical" locations with good safety and efficacy. These data have to be confirmed in large prospective series.

Persistent Opacification of the Woven EndoBridge Device: A Conebeam CT Analysis of the Bicêtre Occlusion Scale Score 1 Phenomenon.

BACKGROUND AND PURPOSE: Some Woven EndoBridge devices present a persistent intradevice opacification at imaging follow-up, described as the Bicêtre Occlusion Scale Score 1 (BOSS 1) phenomenon. The clinical implications remain unknown. We aimed here to analyze the factors influencing this occurrence and to precisely describe the evolution of BOSS 1 with time using conebeam CT. MATERIALS AND METHODS: We retrospectively analyzed a prospectively maintained Woven EndoBridge database at our tertiary center and included all patients with isolated BOSS 1 and BOSS 1 associated with small neck remnant (BOSS 1 + 2). RESULTS: Two hundred sixty-seven aneurysms were treated with a Woven EndoBridge device between July 2012 and December 2021. Follow-up with DSA was available for 220 aneurysms (median, 5 months), among which BOSS 1 and 1 + 2 were found in 9.1% (20/220) (95% CI, 5.5%-12.7%). A second DSA follow-up (median, 17 months) was performed in 15 of these 20 aneurysms, which revealed that 40% had evolved to complete Woven EndoBridge occlusion, 33% showed a decreased persistent opacification, and 27% remained stable. BOSS 1 was significantly associated with postoperative antiplatelet medication, a lower aneurysm aspect ratio, and the use of the Woven EndoBridge 17 (P < .05). The average Woven EndoBridge shape modification was less pronounced in the BOSS 1 population (P < .02). None of the BOSS 1 or 1 + 2 aneurysms required retreatment or were associated with hemorrhage occurrence. CONCLUSIONS: Isolated persistent flow inside the Woven EndoBridge device at follow-up is rare and notably associated with antiplatelet prescription. It seems to present a benign course in most cases.

Aneurysm Treatment with Woven EndoBridge-17: Angiographic and Clinical Results at 12 Months from a Retrospective, 2-Center Series.

BACKGROUND AND PURPOSE: This retrospective, 2-center study investigated the feasibility, safety, and efficacy at 12-month follow-up of the treatment of ruptured, unruptured, and recurrent intracranial aneurysms using the latest generation of the Woven EndoBridge (WEB) device, the WEB-17 system. MATERIALS AND METHODS: Aneurysms treated with WEB-17 were extracted from the databases of 2 neurovascular centers. Patients, aneurysm characteristics, complications, and clinical and anatomic results were analyzed. RESULTS: From February 2017 to May 2021, two hundred twelve patients with 233 aneurysms (181/233, 77.7%, unruptured-recurrent, and 52/233, 22.3%, ruptured) were included. High treatment feasibility (95.3%) was reported and was similar in ruptured aneurysms (94.2%) and unruptured-recurrent aneurysms (95.6%) (P = .71) and in typical (95.4%) and atypical (94.7%) locations (P = .70), but it was lower in aneurysms with an angle between the parent artery and main aneurysm axis of ≥45° (90.2%) compared with those with an angle of <45° (97.1%) (P = .03). Global mortality and morbidity were 1.9% and 3.8% at 1 month, respectively, and 4.4% and 1.9% at 12 months, respectively. One-month morbidity (P = .02) and mortality (P = .003) were higher in the ruptured group (10.0% and 8.0%, respectively) compared with unruptured-recurrent group (1.9% and 0.0%, respectively). Overall adequate occlusion (complete occlusion and neck remnant) was 86.3%. The percentage of adequate occlusion was higher (P = .05) in the unruptured-recurrent group (88.5%) compared with the ruptured group (77.5%). CONCLUSIONS: The WEB-17 system showed high feasibility for ruptured and unruptured aneurysms, typical and atypical locations, and some aneurysms with an angle of ≥45°. As the most recent generation device, the WEB-17 also demonstrates high safety and good efficacy.

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.

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.

Aneurysm Characteristics, Study Population, and Endovascular Techniques for the Treatment of Intracranial Aneurysms in a Large, Prospective, Multicenter Cohort: Results of the Analysis of Recanalization after Endovascular Treatment of Intracranial Aneurysm Study.

BACKGROUND AND PURPOSE: The Analysis of Recanalization after Endovascular Treatment of Intracranial Aneurysm (ARETA) prospective study aims to determine factors predicting recurrence after endovascular treatment for intracranial aneurysms. In this publication, we review endovascular techniques and present the study population. Characteristics of treated and untreated unruptured aneurysms were analyzed. MATERIALS AND METHODS: Sixteen neurointerventional departments prospectively enrolled patients treated for ruptured and unruptured intracranial aneurysms between December 2013 and May 2015. Patient demographics, aneurysm characteristics, and endovascular techniques were recorded. RESULTS: A total of 1289 patients with 1761 intracranial aneurysms, 835 (47.4%) ruptured, were enrolled. Of these, 1359 intracranial aneurysms were treated by endovascular means. Ruptured intracranial aneurysms were treated by coiling and balloon-assisted coiling in 97.8% of cases. In unruptured intracranial aneurysms, the rates of flow diversion, flow disruption, and stent-assisted coiling were 11.6%, 6.9%, and 7.8%, respectively. Rupture status and aneurysm location, neck diameter, and sac size significantly influenced the chosen technique. Treated unruptured intracranial aneurysms, compared with untreated counterparts, had larger aneurysm sacs (7.6 ± 4.0 versus 3.4 ± 2.0 mm; P < 0.001) and neck dimensions (4.1 ± 2.2 versus 2.4 ± 1.3 mm; P < 0.001) and more frequently an irregular form (84.6% versus 44.4%; P < 0.001). Also, its location influenced whether an unruptured intracranial aneurysm was treated. CONCLUSIONS: Our study provides an overview of current neurointerventional practice in the ARETA cohort. The technique choice was influenced by aneurysm morphology, location, and rupture status. Flow diversion, flow disruption, and stent-assisted coiling were commonly used in unruptured intracranial aneurysms, while most ruptured intracranial aneurysms were treated with coiling and balloon-assisted coiling.

[Endovascular treatment of non-ruptured intracranial aneurysms: critical analysis of the literature]. / Traitement endovasculaire des anévrismes intracrâniens non rompus: analyse critique de la littérature.

BACKGROUND: The goal was to evaluate, from the published data, the results of the endovascular treatment of unruptured aneurysms. METHODS: We have searched Medline for studies publishing results for endovascular coiling of unrupured aneurysms. Studies were classified as single-center, multicenter, or meta-analysis. RESULTS: Single-center studies always underestimate morbidity and mortality rates. However, it is possible to estimate mortality rate around 1.5% and morbidity rate between 3 and 6%. Some published series have directly compared results of endovascular treatment with surgical treatment. The results are always in favour of endovascular treatment, demonstrating a lower rate of complications and lower total hospital charges. CONCLUSION: All published series of unruptured aneurysms favour the endovascular treatment instead of surgery. However, there is a lack of multicenter prospective series evaluating the results of the endovascular treatment of unruptured aneurysms. Likewise, there is no scientific arguments demonstrating that preventive treatment of unruptured aneurysms decreases the mortality and allows to decrease the risk of neurologic sequellae.

Lymphographic-Like Technique for the Treatment of Microcystic Lymphatic Malformation Components of <3 mm.

BACKGROUND AND PURPOSE: The treatment of microcystic lymphatic malformations remains challenging. Our aim was to describe the lymphographic-like technique, a new technique of slow bleomycin infusion for the treatment of microcyst components of <3 mm, performed at our institution. MATERIALS AND METHODS: A retrospective analysis of a prospectively collected lymphatic malformation data base was performed. Patients with at least 1 microcystic lymphatic malformation component demonstrated on MR imaging treated by lymphographic-like technique bleomycin infusion were included in the study. Patient interviews and MR imaging were performed to assess subjective and objective (microcystic lymphatic malformation size decrease of >30%) clinical improvement, respectively. Patients were reviewed 3 months after each sclerotherapy session. Lymphographic-like technique safety and efficacy were assessed. RESULTS: Between January 2012 and July 2016, sixteen patients (5 males, 11 females; mean age, 15 years; range, 1-47 years) underwent the bleomycin lymphographic-like technique for microcystic lymphatic malformations. Sixty sclerotherapy sessions were performed, with a mean of 4 sessions per patient (range, 1-8 sessions) and a mean follow-up of 26 months (range, 5-58 months). We observed no major and 3 minor complications: 1 eyelid infection, 1 case of severe postprocedural nausea and vomiting, and 1 case of skin discoloration. One patient was lost to follow-up. Overall MR imaging objective improvement was observed in 5/16 (31%) patients; overall improvement of clinical symptoms was obtained in 93% of treated patients. CONCLUSIONS: The bleomycin lymphographic-like technique for microcystic lymphatic malformations is safe and feasible with objective improvement in about one-third of patients. MR signal intensity changes after the lymphographic-like technique are associated with subjective improvement of the patient's symptoms.

Nidal embolization of brain arteriovenous malformations using Onyx in 94 patients.

BACKGROUND AND PURPOSE: To report our experience in the treatment of brain arteriovenous malformations (BAVMs) using Onyx (ev3, Irvine, Calif). PATIENTS AND METHODS: From January 1999 to October 2004, 94 patients with BAVMs were treated endovascularly in our department. They were 51 (54%) men and 43 (46%) women with a mean age of 32 years. A total of 210 endovascular procedures were performed with Onyx as the sole embolic agent in 88 procedures; Onyx and n-butyl cyanoacrylate (n-BCA) were used in combination in 50 procedures, and n-BCA alone was used in 72 procedures. RESULTS: The course of endovascular treatment was completed in 53 patients. In 26 patients (49%, 26/53) an angiographic cure was achieved using embolization as the sole therapeutic technique. Seven (13%, 7/53) patients underwent a surgical resection of the residual BAVM nidus, 20 (38%, 20/53) patients underwent radiosurgical treatment after nidal size reduction <2 cm was accomplished by endovascular treatment. Further endovascular treatment was planned in 33 patients, whereas in 5 patients, the continuation of embolization was aborted due to difficult nidus catheterization. Procedure-related permanent neurologic deficits were observed in 8 (8.5%, 8/94) patients. There were 3 procedure-related deaths. CONCLUSION: Onyx is suitable for brain BAVM embolizations and allows obtaining higher rates of anatomic cures compared with those obtained previously with other embolic agents.

[Preoperative mixed embolization of a paraganglioma using Onyx]. / Embolisation préopératoire par abord mixte d'un paragangliome à l'aide d'Onyx.

Paragangliomas, or glomus tumors, are highly vascular benign tumors of the head and neck. Clinical symptoms are essentially progressive and neurological, involving infiltration of the regional cranial nerves. The usual treatment is surgery, which itself is a challenge because of the close proximity of vital structures and the considerable blood loss. Preoperative embolization can reduce morbidity, and several techniques have been described using arterial injection of particles or of cyanoacrylate directly into the tumor. This case report is of a patient treated by surgery using a new technique-preoperative embolization involving both the arteries and veins, and injection of Onyx, resulting in complete devascularization of the tumor's arteriovenous network.

Understanding Angiography-Based Aneurysm Flow Fields through Comparison with Computational Fluid Dynamics.

BACKGROUND AND PURPOSE: Hemodynamics is thought to be an important factor for aneurysm progression and rupture. Our aim was to evaluate whether flow fields reconstructed from dynamic angiography data can be used to realistically represent the main flow structures in intracranial aneurysms. MATERIALS AND METHODS: DSA-based flow reconstructions, obtained during interventional treatment, were compared qualitatively with flow fields obtained from patient-specific computational fluid dynamics models and quantitatively with projections of the computational fluid dynamics fields (by computing a directional similarity of the vector fields) in 15 cerebral aneurysms. RESULTS: The average similarity between the DSA and the projected computational fluid dynamics flow fields was 78% in the parent artery, while it was only 30% in the aneurysm region. Qualitatively, both the DSA and projected computational fluid dynamics flow fields captured the location of the inflow jet, the main vortex structure, the intrasaccular flow split, and the main rotation direction in approximately 60% of the cases. CONCLUSIONS: Several factors affect the reconstruction of 2D flow fields from dynamic angiography sequences. The most important factors are the 3-dimensionality of the intrasaccular flow patterns and inflow jets, the alignment of the main vortex structure with the line of sight, the overlapping of surrounding vessels, and possibly frame rate undersampling. Flow visualization with DSA from >1 projection is required for understanding of the 3D intrasaccular flow patterns. Although these DSA-based flow quantification techniques do not capture swirling or secondary flows in the parent artery, they still provide a good representation of the mean axial flow and the corresponding flow rate.

Large Basilar Apex Aneurysms Treated with Flow-Diverter Stents.

BACKGROUND AND PURPOSE: The treatment of wide-neck, large basilar apex aneurysms is challenging with either an endovascular or a surgical approach. The aim of the present study was to report our experience treating basilar apex aneurysms with flow-diverter stents and to evaluate their efficacy and safety profile in this specific anatomic condition. MATERIALS AND METHODS: We retrospectively analyzed data from all consecutive patients treated with flow-diverter stents at our institution between January 2011 and January 2015. Patients with large basilar apex aneurysms treated with a flow-diverter stent were included in the study. Clinical presentations, technical details, intra- and perioperative complications, and clinical and angiographic outcomes were recorded, with a midterm follow-up. RESULTS: Of the 175 aneurysms treated with flow-diverter stents at our institution, 5 patients (2 women and 3 men; age range, 44-58 years) received flow-diverter stent for basilar apex aneurysms. The mean follow-up after stent deployment was 21 months (range, 15-24 months). One patient died on day 31 from an early postprocedural midbrain hemorrhage. One patient had a right cerebellar hemispheric ischemic lesion with a transient cerebellar syndrome resolved within 24 hours without neurologic sequelae at the latest follow-up. The mRS was 0 in 4 patients and 6 in 1 patient at last follow-up. CONCLUSIONS: Flow diversion is a feasible technique with an efficacy demonstrated at a midterm follow-up, especially in the case of basilar apex aneurysm recurrences after previous endovascular treatments. Concern about its safety profile still exists.

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.

Ellipsoid approximation versus 3D rotational angiography in the volumetric assessment of intracranial aneurysms.

BACKGROUND AND PURPOSE: The purpose of this study was to compare the volumetric results of intracranial aneurysms obtained by calculation of the volume of an ellipsoid with those obtained with 3D rotational angiography (3D-RA). METHODS: First, the precision of 3D-RA in the assessment of volumetric measurement of intracranial aneurysm had to be established. The 3D-RA gave an overestimation of 4% to 5.5% of the actual volume of a spherical object. Then, 484 consecutive human intracranial aneurysms were studied with 3D-RA, allowing the determination of their volume. In the meantime, aneurysm dimensions (height and width) were measured on the 3D pictures generated by the 3D-RA. The aneurysm volumes were obtained by considering the aneurysm shape to be ellipsoidal, according to the formula: (formula in text). RESULTS: The calculated aneurysm volume (V(calc)) overestimated by 15 +/- 38% the volume given by 3D-RA. Taking into account a 10% margin of error, 227 (47%) aneurysms were overestimated by 44 +/- 34%, whereas 113 (23%) aneurysms were underestimated by 25 +/- 12%. Only 144 (30%) aneurysms had calculated and 3D-RA results within the limits of 10% of discrepancy. Concordance was good for pericallosal and basilar tip aneurysms (mean overestimation of 6 +/- 22% and 8 +/- 27%, respectively). Conversely, there was a high discrepancy between calculated and 3D-RA results for posterior communicating artery aneurysms (mean overestimation of 22 +/- 44%). CONCLUSION: The calculation of the volume based on aneurysm dimensions is relatively accurate for pericallosal and basilar tip aneurysms, probably owing to their spherical or elliptic shape. Conversely, this formula is not adequate for irregularly shaped lesions, such as posterior communicating aneurysms.

[Transarterial embolisation of intracranial dural arteriovenous malformations with ethylene vinyl alcohol copolymer (Onyx18)]. / Embolisation par voie artérielle de malformations artérioveineuses durales intracrâniennes à l'aide d'ethylvinyl alcool copolymère (Onyx18).

OBJECTIVE: To report our recent experience in transarterial embolisation of dural arteriovenous malformations (DAVM) using a new liquid embolic agent, Onyx18. PATIENTS AND METHODS: 6 patients were enrolled in this series. Clinical presentation was separated into 2 groups: aggressive (n=2), non aggressive (n=4). The DAVM was located at the superior sagittal sinus (n=1), at the transverse sinus (n=2), at the condylian canal (n=1), in the lesser sphenoid wing region (n=1), and in the tentorium region (n=1). The DAVM drained directly into a condylian or a cortical vein for three patients and into a venous sinus with cortical venous reflux for the three others. In this latter situation, the sinus was anatomically excluded from the normal brain venous drainage. RESULTS: A full brain angiogram including both internal carotid arteries, both external carotid arteries and ipsilateral vertebral artery, was performed before and after each treatment. The feeder chosen after a selective catheterisation for Onyx18 injection was always meningeal. Each treatment consisted of a single Onyx injection after one unique feeder catheterisation. Complete anatomical exclusion of the DAVM was achieved and demonstrated by the post treatment angiogram in all cases. There was no clinical complication after the treatment. CONCLUSION: Onyx18 used is a safe treatment for DAVMs. When its injection is performed in optimal conditions, it fills the total DAVM and its drainage vein or sinus after a single arterial feeder catheterisation.

Retrospective Analysis of Delayed Intraparenchymal Hemorrhage after Flow-Diverter Treatment: Presentation of a Retrospective Multicenter Trial.

BACKGROUND AND PURPOSE: Intracranial aneurysm treatment with flow diverters has shown satisfying results in terms of aneurysm occlusion, and while some cases of delayed intraparenchymal hemorrhage have been described, no systematic analysis of the risk factors affecting its occurrence has been conducted in a large series of patients. This retrospective analysis of delayed intraparenchymal hemorrhage after flow-diverter treatment is a multicenter, retrospective study using a large series of treated patients to analyze factors affecting the occurrence of delayed intraparenchymal hemorrhage. MATERIALS AND METHODS: Patients treated with flow diverters and presenting with delayed intraparenchymal hemorrhage were included from December 2007 to December 2014 in 7 participating centers in France. Patient and aneurysm characteristics were recorded as were characteristics of bleeding (size, lateralization, and time to bleed), treatment, and clinical outcome after 1, 3, and 6 months. RESULTS: Delayed intraparenchymal hemorrhage occurred in 11 patients between 1 and 21 days after the procedure. In 10 of these patients, hemorrhages were ipsilateral to the treated aneurysms. Five of the 11 underwent surgery, and 9 of the 11 had good clinical outcomes at 6 months (mRS ≤2). CONCLUSIONS: The pathogenesis of delayed intraparenchymal hemorrhage occurring after flow-diverter treatment remains unclear. The multidisciplinary management of delayed intraparenchymal hemorrhage yields a relatively low morbidity-mortality rate compared with the initial clinical presentation.

Flow-Diverter Stents for the Treatment of Saccular Middle Cerebral Artery Bifurcation Aneurysms.

BACKGROUND AND PURPOSE: The flow-diverter stent has been proved a feasible, safe, and efficient technique, particularly for the treatment of large and broad-neck carotid siphon aneurysms. Wide-neck bifurcation aneurysms remain, in some cases, a challenge for neurointerventionalists. We report the outcomes of the treatment of saccular middle cerebral artery bifurcation aneurysms with flow diversion in our institution. MATERIALS AND METHODS: From the institution data base, all saccular, nondissecting MCA bifurcation aneurysms, treated with flow-diverter stents, were retrospectively reviewed. Technical issues, immediate posttreatment and follow-up angiographic findings, and clinical outcomes were assessed. RESULTS: Fourteen patients with 15 aneurysms were included in the study. Ischemic complications, as confirmed by MR imaging, occurred in 6 patients (43%). Procedure-related morbidity and mortality at last follow-up were 21% and 0%, respectively. Angiographic follow-up was available for 13 aneurysms, with a mean follow-up of 16 months. Complete occlusion was obtained for 8 aneurysms (62%). CONCLUSIONS: Compared with other available therapeutic options, the flow-diverter stent does not appear to be a suitable solution for the treatment of saccular MCA bifurcation aneurysms.