In recent years, venous sinus stenosis has been shown to be a key underlying contributor to idiopathic intracranial hypertensions (IIH) and the most common cause of pulsatile tinnitus (PT). Recent advancements in noninvasive venous imaging have improved the detection of venous sinus stenosis in IIH patients, and growing evidence supports a pathophysiological relationship between venous sinus stenosis, reduced cerebrospinal fluid (CSF) absorption, and elevated intracranial pressure (ICP) in a substantial subset of this population. The growing use of venous sinus stenting (VSS) as an effective treatment for sequelae of venous sinus stenosis highlights the importance of developing standardized, evidence-based diagnostic and management guidelines. A multidisciplinary roundtable of academic, government, and industry cerebrovascular experts convened at the ARISE II meeting to discuss existing evidence and develop areas of expert consensus. These discussions focused on developing standardized patient selection, diagnostic evaluation, procedural considerations, and post-treatment follow-up for VSS. Expert consensus supports VSS as a safe and effective therapy for appropriately selected patients with venous sinus stenosis. The recommendations discussed in this paper aim to standardize patient care, optimize outcomes, and identify opportunities for further investigation.

BACKGROUND:Posterior circulation (PC) aneurysms are associated with a higher risk of rupture. Flow diverters (FDs) are widely used for carotid intracranial aneurysms, but their role in PC aneurysms is less established. This meta-analysis examines the available literature on the safety and effectiveness of FDs for PC aneurysms. METHOD:We conducted a systematic search from database inception until October 2024. The primary effectiveness outcome was complete occlusion rate defined by the Raymond-Roy and/or O'Kelly-Marotta scales. Primary safety outcomes included thromboembolic event rates following implantation. Secondary outcomes included procedure-related mortality, good functional outcome (GFO), and retreatment. Pool estimates were calculated using a random-effect model. Subgroup analysis based on morphology and study design was also conducted. RESULTS:A total of 42 studies met our inclusion criteria. A total of 1698 patients were treated with FDs for 1760 PC aneurysms. Among these cases, 47.6% were in the vertebral artery. Our pooled overall analysis of complete occlusion rates was 72.73% (P<0.0001; I2=67.2%), and the pooled thromboembolic events rate following implantation was 11.70% (P<0.0046; I2=70.5%). Additionally, the pooled mortality rate was 8.07% (P<0.0001; I2=61.5%), the retreatment rate was 6.59% (P<0.4260; I2=1%), and the pooled GFO rate was 83.99% (P<0.0001; I2=76%). Subgroup analysis revealed that fusiform-dolichoectatic had a complete occlusion rate of 48.29% (P<0.3223; I2=11.7%). CONCLUSION:FDs for PC aneurysms achieve generally adequate occlusion rates, except in dolichoectatic-fusiform subtypes. Despite achieving adequate occlusion rates, FD use was associated with higher thromboembolic events, mortality, and retreatment rates, which necessitates careful patient selection.

BACKGROUND AND OBJECTIVES: The prospective single-arm nonrandomized SCENT (Surpass Intracranial Aneurysm Embolization System Pivotal) trial on flow diverter treatment of large and giant intracranial aneurysms (IA) was analyzed for patients' age and IA characteristics affecting stroke and occlusion rates over 5 years (Trial registration NCT01716117). METHODS: Impact on major ipsilateral stroke and IA occlusion was studied by stratifying age as 65 years and younger vs older than 65. Kaplan-Meier estimates of time to both endpoints, stratified by age, were created. Univariate predictors of time-to-stroke were analyzed using univariable proportional hazards regression models. Limited bivariable modeling was also attempted. RESULTS: Of 180 patients with large or giant IA enrolled, 119 were 65 years and younger, whereas 61 were older than 65 years. The 3-year risk of stroke for the older than 65 years group (19.7%) was more than double that of the 65 years and younger group (9.2%), P = .047. No new strokes were reported between 3 and 5 years. Four patients (2.2%) experienced aneurysm rupture within the first week post-treatment, 3 being 65 years and younger and the fourth older than 65 (>.99). Complete IA occlusion within age strata at 1 year was: older than 65 60% (33/55), 65 years and younger 79.1% (87/110), P = .009, 3 years: older than 65 67.6% (25/37), 65 years and younger 82.5% (66/80), P = .071, and 5 years: older than 65 85.7% (18/21), 65 years and younger 91.8% (56/61), P = .417. CONCLUSION: Age older than 65 was associated with an increased risk of stroke and predictive of incomplete healing and increased time to healing.

Background:Flow diverters (FDs) are the first line of treatment for specific intracranial aneurysms. However, aneurysm persistence at follow-up presents in up to 25%. Occlusion after flow diversion in older patients seems less effective due to clinical, anatomical, and physiological characteristics. We aimed to study the effect of age on aneurysm occlusion mediated by intraprocedural technical events. Methods:We conducted a pooled analysis of 2 cohorts, including patients with unruptured saccular aneurysms in the internal carotid artery, treated with the Surpass Streamline FD. Multivariable logistic regression was used to identify predictors of complete occlusion at 12-month follow-up. A mediation analysis was performed to assess the role of intraprocedural technical events (eg, fish-mouthing of the distal end, poor device opening, FD twisting, foreshortening, excess friction of the FD and the delivery system during deployment, and delivery system kink) in the relationship between age and occlusion rates. Results:A total of 316 patients (mean age 59.4 ± 11.2 years) were included. Complete aneurysm occlusion was achieved in 82% of cases at 12 months. Increasing age was associated with lower odds of occlusion (adjusted odds ratio = 0.962, P<0.001) and a higher incidence of intraprocedural technical events (adjusted odds ratio = 1.088, P<0.001). Intraprocedural technical events were inversely associated with occlusion (adjusted odds ratio = 0.265, P = 0.004), and mediation analysis revealed that 16.3% of the effect of age on aneurysm occlusion was mediated by these events. Conclusion:Intraprocedural technical events partially mediate the effect of age on complete aneurysm occlusion after FD treatment. Identifying additional mechanisms that influence occlusion could improve procedural outcomes, particularly in older patients.

Intracranial atherosclerotic disease (ICAD) is one of the leading causes of ischemic stroke worldwide. Despite advances in its diagnosis and management, there is no clear consensus on best practices to manage ICAD. This report summarizes the ARISE II (Roundtable Discussion With Industry and Stroke Experts) consensus in treating ICAD. The consensus underscored the importance of lifestyle modification and medical management in patients with ICAD. Patients who fail medical management are candidates for endovascular treatment. Open surgery is not recommended in patients who lack demonstrated hemodynamic insufficiency. The consensus also identified gaps in knowledge about the optimal duration of antithrombotics, the effect of the CYP2C19 genotype on medical management, the need for newer devices, and the standardization of antithrombotic protocols before stenting in an acute setting. Optical coherence tomography requires additional clinical data before defining its role in the diagnosis of ICAD.

Background One-year and 3-year outcomes for the SCENT trial have previously been reported. However, 5-year (long-term) clinical outcomes have not previously been described. Methods In this multicenter prospective trial, 180 aneurysms in 180 subjects were treated with the Surpass flow diverter system across 26 sites. Patients were followed according to a standardized protocol at 1 month, 6 months, 1 year, 3 years, and 5 years. Aneurysm occlusion, in-stent stenosis, modified Rankin Scale (mRS) scores, and complications were recorded. Results The 5-year clinical follow-up reported 119 subjects and nine deaths with a completion rate of 71.7%, with 5-year angiographic follow-up available in 82 of the surviving 171 patients (48%). Aneurysm occlusion (Raymond Class I) for those patients who underwent angiographic follow-up was 77.8% (91/117) and 90.2% (74/82) at 3 and 5 years. The primary effectiveness composite endpoint was achieved in 80.3% (57/71) of patients. The cumulative proportion of subjects experiencing new or worsening major ipsilateral stroke was 12.8% (23/180) at 36 months, with no new occurrences at 60 months. No late aneurysm ruptures occurred during the 5-year follow-up, and no additional retreatments occurred between 36 and 60 months. Between 3 and 5 years, 52 potential site-reported serious adverse events were sent to CEC for adjudication. Of these, nine were CEC-adjudicated to be serious and four were determined to be related to the procedure/device. Conclusions Five-year findings demonstrate the long-term safety and effectiveness of the Surpass flow diverter for intracranial aneurysm treatment, supported by high occlusion rates and low rates of delayed adverse events in this study. Trial registration number NCT01716117 .

BACKGROUND:Intracranial aneurysms (IAs) remain a challenging neurological diagnosis associated with significant morbidity and mortality. There is a plethora of microsurgical and endovascular techniques for the treatment of both ruptured and unruptured aneurysms. There is no definitive consensus as to the best treatment option for this cerebrovascular pathology. The Aneurysm, Arteriovenous Malformation, and Chronic Subdural Hematoma Roundtable Discussion With Industry and Stroke Experts discussed best practices and the most promising approaches to improve the management of brain aneurysms. METHODS:A group of experts from academia, industry, and federal regulators convened to discuss updated clinical trials, scientific research on preclinical system models, management options, screening and monitoring, and promising novel device technologies, aiming to improve the outcomes of patients with IA. RESULTS:Aneurysm, Arteriovenous Malformation, and Chronic Subdural Hematoma Roundtable Discussion With Industry and Stroke Experts suggested the incorporation of artificial intelligence to capture sequential aneurysm growth, identify predictors of rupture, and predict the risk of rupture to guide treatment options. The consensus strongly recommended nationwide systemic data collection of unruptured IA radiographic images for the analysis and development of machine learning algorithms for rupture risk. The consensus supported centers of excellence for preclinical multicenter trials in areas such as genetics, cellular composition, and radiogenomics. Optical coherence tomography and magnetic resonance imaging contrast-enhanced 3T vessel wall imaging are promising technologies; however, more data are needed to define their role in IA management. Ruptured aneurysms are best managed at large volume centers, which should include comprehensive patient management with expertise in microsurgery, endovascular surgery, neurology, and neurocritical care. CONCLUSIONS:Clinical and preclinical studies and scientific research on IA should engage high-volume centers and be conducted in multicenter collaborative efforts. The future of IA diagnosis and monitoring could be enhanced by the incorporation of artificial intelligence and national radiographic and biologic registries. A collaborative effort between academic centers, government regulators, and the device industry is paramount for the adequate management of IA and the advancement of the field.

ARISE (Aneurysm/AVM/cSDH Roundtable Discussion With Industry and Stroke Experts) organized a one-and-a-half day meeting and workshop and brought together representatives from academia, industry, and government to discuss the most promising approaches to improve outcomes for patients with chronic subdural hematoma (cSDH). The emerging role of middle meningeal artery embolization in clinical practice and the design of current and potential future trials were the primary focuses of discussion. Existing evidence for imaging, indications, agents, and techniques was reviewed, and areas of priority for study and key questions surrounding the development of new and existing treatments for cSDH were identified. Multiple randomized, controlled trials have met their primary efficacy end points, providing high-level evidence that middle meningeal artery embolization is a potent adjunctive therapy to the standard (surgical and nonsurgical) management of neurologically stable cSDH patients in terms of reducing rates of disease recurrence. Pooled data analyses following the formal conclusion and publication of these trials will form a robust foundation upon which guidelines can be strengthened for cSDH treatment modalities and optimal patient selection, as well as delineate future lines of investigation.

Background Flow diversion (FD) has emerged as an effective treatment option for intracranial aneurysms. However, there is limited evidence regarding its safety and efficacy specifically for distal and small‐artery aneurysms of the posterior circulation. This study aimed to investigate the outcomes of FD for aneurysms arising from the posterior inferior cerebellar artery, anterior inferior cerebellar artery, superior cerebellar artery, and the P2 and P3 segments of the posterior cerebral artery. Methods This is a subanalysis of the Post‐FD (Posterior Circulation Aneurysms Treated With Flow Diversion) registry, highlighting distal aneurysms in the posterior inferior cerebellar artery, anterior inferior cerebellar artery, superior cerebellar artery, and the P2 and P3 segments of the posterior cerebral artery treated with FD. Aneurysm characteristics and patient outcomes were described for the total series, and a more focused analysis comparing fusiform/dissecting versus saccular aneurysms was performed. The primary treatment outcome was complete aneurysm occlusion (Raymond–Roy class 1). Primary safety outcome was major ischemic/hemorrhagic stroke following FD. Secondary outcomes included functional outcome, aneurysm retreatment, and in‐stent stenosis. Results Overall, 36 patients with 36 aneurysms were treated with FD, with a median age of 60.0 years (interquartile range [IQR], 52.8—65.3 years). Of those, 13 were fusiform/dissecting, while 23 were saccular aneurysms. Complete occlusion was achieved in 78.1% for all aneurysms at a median follow‐up of 14.0 months (IQR, 9.3–48.6 months). There was a nonsignificant trend in rates of complete occlusion between fusiform/dissecting (91.7%) and saccular aneurysms (70%; P = 0.151). Major stroke was reported in 2 cases (5.6%) and in‐stent stenosis in 4 (11.1%), and retreatment was required for 4 aneurysms (11.4%) There was no difference in rates of major stroke, in‐stent stenosis, or retreatment between fusiform/dissecting and saccular aneurysms. Conclusion This study suggests the safety and feasibility of FD for distal aneurysms of the posterior circulation, particularly fusiform/dissecting aneurysms. Further larger‐scale studies are warranted to confirm these findings.

To investigate the outcomes of flow diversion for distal aneurysms of the posterior circulation.

Brain arteriovenous malformations (bAVMs) are complex, and rare arteriovenous shunts that present with a wide range of signs and symptoms, with intracerebral hemorrhage being the most severe. Despite prior societal position statements, there is no consensus on the management of these lesions. ARISE (Aneurysm/bAVM/cSDH Roundtable Discussion With Industry and Stroke Experts) was convened to discuss evidence-based approaches and enhance our understanding of these complex lesions. ARISE identified the need to develop scales to predict the risk of rupture of bAVMs, and the use of common data elements to perform prospective registries and clinical studies. Additionally, the group underscored the need for comprehensive patient management with specialized centers with expertise in cranial and spinal microsurgery, neurological endovascular surgery, and stereotactic radiosurgery. The collection of prospective multicenter data and gross specimens was deemed essential for improving bAVM characterization, genetic evaluation, and phenotyping. Finally, bAVMs should be managed within a multidisciplinary framework, with clinical studies and research conducted collaboratively across multiple centers, harnessing the collective expertise and centralization of resources.

ABSTRACTImportanceThe multicenter, prospective, single-arm, non-randomized SCENT trial on flow diverter (FD) treatment for intracranial aneurysms (IA) was analyzed for patients’ age and IA characteristics impacting stroke and occlusion rates over 5 years.DesignThe impact on major ipsilateral stroke and IA occlusion was studied by stratifying age as ≤ 65 years versus >65 years. Product-limit (Kaplan-Meier) estimates of time to both endpoints, stratified by age group, were created. Univariate predictors of time to stroke were identified by including candidate variables in univariable proportional hazards regression models. Those variables found to be significant (p<0.10) at the univariate level were entered into a multivariable survival model to identify independent predictors. The stepwise selection produced a final reduced model with a significance level to both enter and stay set at 0.05.FindingsOf 180 patients with 180 large or giant IA enrolled in the modified intention-to-treat cohort, 119 subjects were ≤ 65, while 61 patients were > 65 years old. When parent artery stenosis and IA size were entered into a multiple-stepwise survival model, only stenosis remained as an independently significant predictor of time to stroke. At 3-year follow-up, there were a total of 23 strokes (12.8%), with 11 occurring in subjects ≤ 65 years; there was a greater risk for seniors (HR1.96, 95% CI 0.83-4.78). Four patients (4/180; 2.2%) experienced aneurysm rupture within the first week post-treatment, with 3 being ≤ 65 and the fourth aged 66 years. No new strokes were reported between 3 and 5 years. Complete IA occlusion rates for seniors were 60.0% (33/55), 67.6% (25/37), and 85.7% (18/21) at 12, 36, and 60 months, respectively, as compared to 79.1% (87/110), 82.5% (66/80), and 91.8% (56/61) for younger subjects. The time to complete IA occlusion was shorter in younger patients (HR1.53, 95% CI 1.07-2.19). Five subjects (2.8%) underwent retreatment, 2 in 60-year-old patients, and one each aged 64, 70, and 75.Conclusions and RelevanceAge > 65 and parent artery stenosis are related to an increased risk of major ipsilateral stroke in patients with intracranial aneurysms treated with a flow diverter. Age > 65 is also predictive of increased time to and incomplete healing. With demographic shifts, future treatments need to focus on expedited and improved healing.Trial Registrationhttps://www.clinicaltrials.govNCT01716117KEY POINTSQuestionWhat key variables, including patients’ age and intracranial aneurysm (IA) characteristics, determine procedural stroke risks in subjects treated for large or giant IA with flow-diverting stents?FindingsAneurysm size and parent artery stenosis impacted occlusion rates and stroke risk, respectively. Over a 5-year observation period, the senior population had a significantly lower occlusion rate and higher risk for stroke, while the younger population was at higher risk for early aneurysm bleed following treatment.MeaningWith demographic shifts and a higher senior population being treated for IA, the stroke risk and incomplete occlusion rates need to be discussed with the patient before treatment.

Background and purpose Flow diversion has established as standard treatment for intracranial aneurysms, the Surpass Streamline is the only FDA-approved braided cobalt/chromium alloy implant with 72-96 wires. We aimed to determine the safety and efficacy of the Surpass in a post-marketing large United States cohort. Materials and methods This is a retrospective multicenter study of consecutive patients treated with the Surpass for intracranial aneurysms between 2018 and 2021. Baseline demographics, comorbidities, and aneurysm characteristics were collected. Efficacy endpoint included aneurysm occlusion on radiographic follow-up. Safety endpoints were major ipsilateral ischemic stroke or treatment-related death. Results A total of 277 patients with 314 aneurysms were included. Median age was 60 years, 202 (73%) patients were females. Hypertension was the most common comorbidity in 156 (56%) patients. The most common location of the aneurysms was the anterior circulation in 89% (279/314). Mean aneurysm dome width was 5.77 +/- 4.75 mm, neck width was 4.22 +/- 3.83 mm, and dome/neck ratio was 1.63 +/- 1.26. Small-sized aneurysms were 185 (59%). Single device was used in 94% of the patients, mean number of devices per patient was 1.06. At final follow-up, complete obliteration rate was 81% (194/239). Major stroke and death were encountered in 7 (3%) and 6 (2%) cases, respectively. Conclusion This is the largest cohort study using a 72-96 wire flow diverter. The Surpass Streamline demonstrated a favorable safety and efficacy profile, making it a valuable option for treating not only large but also wide-necked small and medium-sized intracranial aneurysms.

Background Approximately 125,000 new cases of occlusive hydrocephalus are seen every year leading to 40,000 operations every year in the US. Occlusive hydrocephalus has been treated tradition ally by surgically placed ventriculo-lumbar or ventriculo-peritoneal shunts. Complications include CSF overdrainage, proximal and distal shunt obstruction as well as infections necessitating 48% reoperations in children within 3 years. Approximately 62,500 shunts are replaced every year and 50% will have to be replaced within 5 years. More recently transcranial rigid and flexible neuroendoscopes are used for 3rd ventriculostomy with immediate effect. About 25% of patients are treated by surgical 3rd ventriculostomy using neuroendoscopes. Objective Based on our previous successful catheter navigation in pediatric population for gene delivery to the skull base,1 2 we propose a minimally invasive translumbar endocisternal approach to a 3rd ventriculostomy (EVT). Methods 3D printed cranio-spinal CSF models generated from age-adjusted human data were constructed. Multimodal imaging guidance (MIG) was created and included MRI and ConeBeam CT combined with real-time fluoroscopy. Subsequently access systems compatible with steerable catheter-based systems were developed and refined using the 3D models to perform a translumbar ETV using MIG followed by an assessment of various systems in 10 sheep, including survival studies and in human cadavers. Results MIG required several hours of training to get used to steer systems successfully for an EVT. Sheep models although challenged by access due the small CSF compartment and the location of the spinal cord, helped to tailor access and steerable systems for a safe ETV prior to implemented the procedure into a human cadaver. Intraoperative cisternography and ventriculography as well as histology specimen showed no damage to the spinal cord, brain and vasculature, provided the right tools are used. MIG and training using 3D CSF models are critical for safe and successful ETV in occlusive hydrocephalus. Conclusion Preliminary preclinical studies show that endocisternal 3rd ventriculostomy is feasible but will require multimodality imaging and appropriately constructed tools for a safe procedure and adequate training. The trans-lumbar CSF navigation with direct access to both spinal and intracranial spaces could address not only a occlusive hydrocephalus but disorders such as arachnoid cysts, aquaeductal stenosis and serve for brain/spine biopsies, drug and gene delivery as well as placement of microsensors and implants for neuromodulation using a simple translumbar CSF access. References Taghian T, Marosfoi MG, Puri AS, et al. A safe and reliable technique for CNS delivery of AAV vectors in the cisterna magna. Mol Ther 2020;28:411-421. Flotte TR, Cataltepe O, Puri A, et al. AAV gene therapy for Tay-Sachs disease. Nat Med 2022;28:251-259. Disclosures A. Wakhloo: 1; C; Philips. 2; C; Philips. 4; C; Deinde Medical. 6; C; Philips. J. Chueh: 1; C; Philips. B. Hallacoglu: 5; C; Philips. D. Dresser: 5; C; Deinde Medical. M. Litzenberg: 5; C; Deinde Medical. N. Laxminarain: 5; C; Deinde Medical.

Introduction Flow diverters (FDs) have demonstrated a safe and effective profile for the treatment of intracranial aneurysms with complex morphologies and variable anatomic locations. However, aneurysmal persistence after flow diversion still presents in up to 25% of treated aneurysms. Herein, we aimed to perform a pooled analysis of two large studies (SCENT [Surpass Intracranial Aneurysm Embolization System Pivotal Trial to Treat Large or Giant Neck Wide Neck Aneurysms] and SESSIA [Safety and Efficacy of the Surpass Streamline for Intracranial Aneurysms]) to evaluate the predictors of occlusion at final follow‐up after treatment with a 72–96 wire device. Methods We pooled all data from the SCENT (prospective) and SESSIA (retrospective) studies that included patients treated with the Surpass Streamline. From the studies, a subset of patients with unruptured saccular aneurysms located in the internal carotid artery (ICA) up to its terminus were included. The authors collected baseline demographics, comorbidities, aneurysm dimensions, and procedural and follow‐up characteristics for each patient. For our analysis, the outcome was complete aneurysm occlusion, as reported by the studies. We performed a multivariable logistic regression to identify the predictors of complete occlusion. Next, we performed a mediation analysis framework to identify the causal relationship of the predictors with the outcome. Finally, we calculated the predicted probability of occlusion for the continuous predictors. Results A total of 348 patients with 348 aneurysms were included, 394 devices were implanted (1.13 per patient). Median age was 61 [22‐85] years, and 83.6% were females. Hypertension was the most common comorbidity (57%) followed by hyperlipidemia (36%). The ICA paraophthalmic segment was the most common location (45%), followed by the petrocavernous (29%) and supraclinoid (25%). Median aneurysm size was 7.5 [1‐29] mm, and neck size was 4.3 [1‐23] mm. At the final follow‐up, the complete occlusion rate was 73% (255/348). After adjusting for confounders and accounting for collinearity, the multivariable analysis identified aneurysm size (OR 0.89; 95% CI 0.85‐0.93;p< .001), procedural technical events (OR 0.31; 95% CI 0.15‐0.65;p = .002), and first device length (OR 0.98; 95% CI 0.96‐1.00;p = .036) as predictors of complete occlusion. Age had a non‐significant direct effect on complete occlusion (p = .091) but a significant indirect effect mediated through aneurysm size (p< .001) and technical events (p< .02). Using our model, the predicted probability of occlusion is≥ 75% in aneurysms measuring < 10 mm when no technical events are encountered. However, when technical events are encountered, the probability decreases to 50–75%. Conclusions Successful aneurysm occlusion after flow diversion is associated with aneurysm size, procedural technical events, and FD length. Age does not directly affect occlusion, but its influence is mediated through the aneurysm size and technical events. Therefore, a priori knowledge of the patient and aneurysm characteristics might guide FD selection to favor the best treatment outcomes.

Background To report the 3-year safety and effectiveness of the Surpass Streamline flow diverter in the SCENT trial (Surpass Intracranial Aneurysm Embolization System Pivotal Trial to Treat Large or Giant Wide-Neck Aneurysms). Methods The Surpass Streamline flow diverter device was evaluated in a multicenter, prospective, single-arm, non-randomized interventional trial including patients with uncoilable or previously treated but failed aneurysms of the intracranial internal carotid artery. 3-year outcomes were tabulated with descriptive statistics and compared with 1-year outcomes. Results Of 180 patients in the modified intent-to-treat (mITT) cohort, 36-month clinical and angiographic follow-up was available in 134 and 117 cases, respectively. Effectiveness endpoint of complete aneurysm occlusion without clinically significant stenosis or retreatment was met in 71.8% (79/110, 95% CI 62.4% to 80.0%) of cases. Safety composite endpoint was 12.2% (22/180) over the 3-year period, with two major safety events (ipsilateral ischemic strokes) occurring between 12–36 months. Complete aneurysm occlusion was noted in 77.8% (91/117), and 99.1% (116/117) of the patients demonstrated adequate aneurysm occlusion (complete occlusion or neck residual). There were four cases (2.2%) of aneurysm rupture, all occurring within the first month of the index procedure. Target aneurysm retreatment rate was 2.8% (5/180). Conclusion The present findings support the long-term safety and effectiveness of the Surpass Streamline flow diverter device. Trial registration NCT01716117.

Background Endovascular treatment of brain aneurysms with the use of flow diverting stents, coils and intrasaccular flow disrupters, has been challenged by delayed and incomplete occlusion in more than 20% of treated subjects at 12-month follow-up imaging. Other shortcomings include delayed or incomplete aneurysm occlusion in senior population, early spontaneous rupture of large and giant aneurysms as well as continued aneurysm growth despite angiographic occlusion. Low Laser Light Therapy (LLLT, aka Photobiomodulation) is being used successfully for treatment of superficial birthmarks as well as ulcers of mouth mucosa. Objective We developed a highly flexible optical microfiber technology to deliver LLLT in a preclinical aneurysm animal model and studied early healing response. Methods Single highly flexible 0.014' optical microfiber system were developed to deliver low laser light through a standard microcatheter. Optimization of delivery technology was carried out in vitro studies using various human cerebrovascular/aneurysm replica. Subsequently the LLLT system was assessed in a rabbit elastase aneurysm model. Laser wavelength and energy dose calculations based on aneurysm surface calculation, was obtained from previous cell culture and animal studies. Aneurysms were treated with LLLT followed by coils or flow diverters (test group) or with FD or coil only (control group). Pre- and posttreatment angiograms as well as follow-up angiograms at 3- and 10 days were compared. Following angiograms, animals were sacrificed, and aneurysm and parent artery samples were processed for histology studies and immunofluorescence staining. Results Control samples showed at 3 days still filling of the aneurysm and no significant endothelialization. Albeit partial filling, 3-day sample treated with LLLT, showed amorphous clot filling the aneurysm with early endothelialization of the aneurysm neck and the implant within the parent vessel. At 10 days, FD treated with LLLT showed a complete aneurysm occlusion and neck endothelialization while control aneurysms were still patent with sparse endothelial cells attached to the FD at the aneurysm neck. At 10 days smooth muscle cell actin (SMA, non-specific for myoepithelial cells) and CD 31 (platelet endothelial cell adhesion molecule 1) were found in large numbers in samples treated with LLLT. Although coil compaction at 10 days was seen in both coiled groups, LLLT treated samples showed layering clot/content. Immunostaining revealed high concentration of Fibroblasts and Myofibroblast near the aneurysm wall small number of primarily Lymphocytes and Neutrophils inside the thrombus as compared to the coiled only aneurysms. Conclusion Preliminary preclinical studies show that LLLT delivered in situ in an animal aneurysm model is feasible. Compared with the control group an early healing response with aneurysm scarring and neck occlusion is observed. Our technology represents a unique combination of implantable devices and LLLT, bringing regenerative medicine into endovascular therapeutic realm. Disclosures A. Wakhloo: 1; C; Prometheus Therapeutics. 4; C; Prometheus Therapeutics. Y. Uetake: None. S. Greenfield: None. B. Lieber: 4; C; Prometheus Therapeutics.

Introduction Flow diverters have demonstrated reliable safety and effectiveness for the treatment of selected anterior circulation intracranial aneurysms. However, posterior circulation aneurysms comprise around 10‐15% of all aneurysms, and they frequently present atypical morphological and anatomical characteristics. Furthermore, these lesions have an increased risk of rupture (compared to those in the anterior circulation) with respect to size and higher treatment risks (regardless of the technique). Flow diversion in posterior circulation aneurysms has been described previously with inconsistent clinical and radiological results. Hence, we aimed to compare the safety and effectiveness of FDs in fusiform/dissecting vs. saccular aneurysms located in the vertebrobasilar vessels. Methods We performed a multicenter, retrospective cohort study including 9 centers. All patients treated with FDs for aneurysms located in the posterior circulation (vertebral and basilar arteries) between 2015 and 2022 were included. Patients were divided into two groups according to the morphology of the aneurysm (fusiform/dissecting vs. saccular). The effectiveness outcome was complete aneurysm occlusion (Raymond‐Roy Class 1) at the latest follow‐up. Safety outcomes included the incidence of ischemic/hemorrhagic and mortality. After adjusting for confounders multivariable logistic regressions were performed to compare outcomes of interest. Results A total of 147 patients with 147 aneurysms were included. The fusiform/dissecting group included 85 cases, while the saccular group 62. The saccular group had older patients (median age: fusiform/dissecting, 55 years [45‐64] vs. saccular, 63 years [51‐70.0]; p=.02). The number of female patients was not different between groups (fusiform/dissecting, 42% vs. saccular, 58%; p=.05). Clinical presentation, comorbidities, modified Fisher, and Hunt and Hess were similar. Baseline modified Rankin Score (mRS) was different (mRS 0‐2: fusiform/dissecting, 84% vs. saccular, 98%; p=.030). Previous endovascular treatment (p=.396) was similar. Aneurysm location (most were in the vertebral artery: fusiform/dissecting, 60% vs. saccular, 42%; p=.009) was different. Median aneurysm size (fusiform/dissecting, 10.0 mm [6.5‐18.8] vs. saccular, 5.9 [3.0‐10.0]; p=<.001), and proximal (fusiform/dissecting, 3.6 mm [2.7‐4.1] vs. saccular, 2.8 [2.4‐3.3]; p=<.001) and distal landing (fusiform/dissecting, 3.2 mm [2.5‐3.5] vs. saccular, 2.4 [2.0‐3.0]; p=<.001) zones were different. The number of FDs per patient (>1 FD: fusiform/dissecting, 36% vs. saccular, 10%; p=<.001) and adjunctive coiling (fusiform/dissecting, 89% vs. non‐F, 74%; p= .015) were different. The most commonly implanted was Pipeline Flex (fusiform/dissecting, 55%, vs. saccular, 40%). Thromboembolic (fusiform/dissecting, 8.2%, vs. saccular, 8.1%; p=.97) and hemorrhagic (fusiform/dissecting, 4%, vs. saccular, 10%; p=.125). Mortality was increased in the fusiform/dissecting group (19%) vs saccular (12%) but not different (p=.365). At an overall median follow‐up time of 13.5 [7.4‐28.8] months, complete occlusion was lower in the fusiform/dissecting group (61% vs. F, 63%) but not statistically different (p=.356). Follow‐up mRS was not different (mRS 0‐2: fusiform/dissecting, 73% vs. saccular, 76%; p=.365). 172 (71%) of the cases achieved complete aneurysm occlusion. Multivariable analysis showed that age (OR: 0.96; 95%CI: 0.93‐0.99; p=.008) and location in the basilar artery (OR: 0.09; 95%CI: 0.03‐0.29; p=<.001) were associated with incomplete occlusion at follow‐up. Conclusion Our results suggest that flow diversion can be an effective treatment for fusiform/dissecting and saccular aneurysms located in the posterior circulation. Although the occlusion rates after flow diversion in fusiform/dissecting aneurysms showed a lower rate compared to saccular, the favorable safety profile of FDs allows them to be considered a valuable tool in the neuroinventionalist armamentarium.

Introduction The safe and effective profile of flow diverters (FD) has allowed neuro‐interventionalists to consider them as a versatile tool for the treatment of aneurysms with different morphologies, locations, and characteristics. Optimal deployment with complete wall apposition affects FD performance. However, few devices are suitable for aneurysms in large caliber vessels. Herein, we aimed to describe the safety and efficacy of a large caliber (5 mm) FD for the treatment of intracranial aneurysms. Methods We performed a retrospective, multi‐center cohort study of adult patients in whom a 5 mm Surpass Streamline FD was implanted between 2018 and 2021 in the United States. Efficacy outcome was complete occlusion at final follow‐up. Safety outcomes were ischemic/hemorrhagic events and mortality up to 30 days following the procedure. Secondary safety was assessed by the rate of adjunctive devices/treatments to overcome technical complications and improve wall apposition. Results A total of 29 patients harboring 29 aneurysms were treated with 39 FDs (36 large‐diameter devices). Mean age was 57.8 ± 15.7 years. Aneurysm morphologies were saccular (n = 15), pseudoaneurysm (n = 7), fusiform (n = 6), and dissecting (n = 1). Locations were internal carotid artery (ICA) petro‐cavernous segment (n = 15), ICA paraophthalmic (n = 5), ICA cervical (n = 4), basilar artery (n = 3), and vertebral artery (n = 2). Aneurysm size mean was 11.4 ± 6.7 mm, and neck size mean 6.5 ± 3.9 mm. Proximal FD landing zone vessel diameter was 4.8 ± 1.3 mm and distal 4.5 ± 1.2 mm. At a mean final follow‐up of 12 ± 6 months, 18 (65%) aneurysms were completely occluded. Ischemic/hemorrhagic events occurred in 2 (7%), and 1 patient died during hospitalization. Balloon‐assisted angioplasty was performed in 19 (66%) cases, adjunctive stenting in 8 (28%), and coiling in 1 (3%). Patients who received an adjunctive device/treatment had an 82% (14/17) complete occlusion compared to 66% (4/6) in those who did not. Conclusions The use of large caliber FDs to treat complex intracranial aneurysms located in large‐diameter dysplastic vessels is technically feasible and safe. The use of adjunctive devices and techniques to achieve optimal wall apposition seems crucial to optimize treatment outcomes. Comparative studies with devices specially designed for this patient population might provide further insights into the best device selection.