Faculty Bibliography

Definitive endoluminal reconstruction, widely known as flow diversion, revolutionized treatment of brain aneurysms. A range of targets, by location, size, etiology, and acuity, can be cured with an excellent risk/benefit profile. Requirement for effective antiplatelet state is balanced with superior treatment durability. Implant and delivery system technology continue to evolve. Some aneurysm types/locations remain undertreated. Maximizing efficacy while minimizing risks requires deep understanding of flow diversion principles, pathologic anatomy, endoluminal implants, delivery systems, and clinical management.

Imaging follow-up is an established component of intracranial aneurysm management that allows ongoing assessment of rupture risk and timely intervention to maintain protection from bleeding. Yet the frequency, duration, and imaging modality for follow-up vary widely. This review outlines contemporary imaging techniques and practice for follow-up of treated and untreated aneurysms, highlighting existing knowledge gaps and technical limitations that limit standardization. Updated evidence on the expected evolution and long-term outcome of common treatment strategies is presented to guide accurate reporting of radiological outcome after treatment and considerations regarding follow-up regimen.

Although the concept of treating cerebral aneurysms by filling the sac from the inside (endosaccular) started many years ago first with detachable balloons and then coils, the use of a single metallic resheathable device acting as a flow disruptor is a much more recent innovation. The most studied device among these is certainly the WEB, which became part of standard clinical practice for treatment of wide-neck bifurcation aneurysms. This study reviews the most important features of the WEB device with a short summary of the most important literature. A small section at the end reviews also other endosaccular devices.

PURPOSE/OBJECTIVE:Treating small-caliber vessel aneurysms with flow diverters poses challenges due to narrow luminal diameters and tortuous vasculature, which complicate the navigation and deployment of conventional devices using standard microcatheters. The Silk Vista Baby (SVB, Balt, Montmorency, France) flow diverter was developed to treat intracranial aneurysms located in smaller vessels or more distal segments and is compatible with 0.017″ microcatheters. We present the largest multicenter analysis to date evaluating the outcomes of SVB use in unruptured distal anterior cerebral artery (DACA) aneurysms. METHODS:Retrospective data from 20 centers were reviewed for patients with unruptured DACA aneurysms treated with the SVB. Demographic information, clinical presentation, radiographic characteristics, complications, and outcomes were recorded. RESULTS:Seventy-nine patients (79 DACA aneurysms) were treated between January 2018 and December 2022; 59 were female (74.7%), and the median age was 61 years (IQR 53-67). Most aneurysms were saccular (89.9%), and 65.8% involved a branch. The median parent vessel diameter was 1.9 mm (IQR 1.7-2.1). A single stent was implanted in 97.5% of cases; 2.5% required two stents. The median imaging follow-up duration was 12 months (IQR 9.5-24). At the last follow-up, 76% of aneurysms showed complete or near-complete occlusion (O'Kelly-Marotta scale C or D, Raymond-Roy 1 or 2). Overall, thromboembolic or hemorrhagic complications occurred in 14% of patients, with two cases being symptomatic. The mortality rate was 0%, and the retreatment rate was 1.3%. CONCLUSION/CONCLUSIONS:In this multicenter series, the SVB flow diverter represented a valuable treatment option for distal anterior cerebral artery (DACA) aneurysms.

The anatomy of vertebrobasilar perforators has been widely studied in human cadavers, with most reports found in the neurosurgical literature. These arterial perforators are extremely hard to visualize consistently with traditional two-dimensional digital subtraction angiography, but are reliably visible with cross sectional cone beam CT techniques. A clear understanding of this specific neurovascular anatomy and pathology is essential for informed treatment decisions. This review analyzes the anatomy of vertebrobasilar perforators with a focus on practical implications for aneurysm treatment, particularly flow diversion.

OBJECTIVE:To validate the carotid web (CW) risk stratification assessment described in previous works within a larger cohort of patients with symptomatic and incidentally found asymptomatic CWs. METHODS:A retrospective analysis of our institution's electronic medical records identified all patients with a diagnosis of CW from 2017 to 2024. We included symptomatic patients and those with asymptomatic CWs, that is, incidentally found webs without history of stroke or transient ischemic attack. Patient charts were reviewed for demographics, imaging, comorbidities, and a diagnosis of stroke after diagnosis of asymptomatic CW. All angles were measured as described in previous work on a sagittal reconstruction of neck CT angiography in which the common carotid artery (CCA), external carotid artery, and internal carotid artery (ICA) were well visualized, together with the CW itself. Principal component analysis and logistic regression were performed to evaluate the association between high-risk angles and stroke risk.  RESULTS: Twenty-six symptomatic and 26 asymptomatic patients were identified. Of note, the number of patients with hypertension, hyperlipidemia, and smoking history was 17 (65.0%), 16 (62.0%), and 8 (31.0%) for symptomatic patients and 18 (69.0%), 17 (65.0%), and 15 (58.0%) for asymptomatic patients. All angular measurements showed statistically significant associations with stroke status. The CCA-web-pouch angle showed the strongest association (p=2.07×10⁻⁴), followed by the CCA-pouch-tip angle (p=3.23×10⁻⁴), ICA-web-pouch angle (p=0.004), and ICA-pouch-tip angle (p=0.005). Each additional high-risk angle increased the odds of stroke by 9.47-fold (p<0.0001). The associated probability of stroke increased from 6.3% with no high-risk angles to 39.1% with one high-risk angle and further to 85.9% with two high-risk angles. The model demonstrated high sensitivity, correctly identifying 84.6% of positive cases, and high specificity, correctly identifying 88.5% of negative cases. The F1 score was 0.863, indicating good overall model performance.  CONCLUSION: Given this successful stratification of CWs into high- and low-risk groups, the utilization of geometric CW parameters may play a role in improving patient selection for intervention in the setting of incidentally diagnosed CW. .

BACKGROUND:The Drivewire 24 (DW24) is a newly FDA-cleared 0.024 inch steerable guidewire. Its proximally controlled deflectable tip allows for intravascular steering to facilitate selective navigation of diagnostic or therapeutic catheters. We present the first clinical experience with the DW24. METHODS:All neurointerventional procedures using the DW24 from October 2024 to April 2025 were retrospectively reviewed. Indications, procedural details, DW24 performance, wire-related complications, and operator feedback were assessed. RESULTS:27 procedures were performed utilizing the DW24. Indications included aneurysm (n=16), stroke (n=5), arteriovenous fistula or malformation (n=4), and diagnostic venography (n=2). Technical success was achieved in 92.6% of cases. Target vessels included the MCA, anterior cerebral artery, posterior cerebral artery, internal carotid artery segments, transverse sinus, and torcula. The device's radiopaque, hydrophilic distal tip aided fluoroscopic visibility, and the variable support enabled articulation across a range of aspiration and delivery catheters without requiring additional support devices. The DW24's steerability enabled access to challenging cerebrovascular anatomy, including one stroke case where conventional guidewires failed to reach a distal M2 occlusion. The DW24's intravascular steering also allowed for the delivery of catheters for Pipeline Embolization Device (PED) deployment and facilitated PED post-processing to improve wall apposition without requiring wire removal, reshaping, or balloon angioplasty. Operators observed a short learning curve. There were no device-related complications, though the wire's response to rotational force was a limitation. CONCLUSION/CONCLUSIONS:The DW24 demonstrated a high technical success rate with no device-related complications. Its versatility across catheter sizes and precise controllability facilitate navigating complex cerebrovasculature. Further studies should assess efficacy in larger cohorts across additional clinical scenarios.

BACKGROUND AND OBJECTIVES/OBJECTIVE:Iatrogenic cerebrovascular injury can cause intracranial hemorrhage and pseudoaneurysm formation, putting patients at high risk for postoperative bleeding. No consensus for management exists. This study describes endovascular treatment of these acute injuries with flow diverter stents. METHODS:Electronic medical records were retrospectively reviewed for injury type and etiology, timing of diagnosis, and endovascular management, including antiplatelet regimens, embolization results, and clinical outcome. RESULTS:Six patients were included. Three suffered an injury to the internal carotid artery, 1 suffered an injury to the left anterior cerebral artery, 1 suffered an injury to the right posterior cerebral artery, and 1 suffered an injury to the basilar artery. Four of the 6 injuries occurred during attempted tumor resection, 1 occurred during cerebrospinal fluid leak repair, and 1 occurred during an ophthalmic artery aneurysm clipping. All injuries resulted in pseudoaneurysm formation. Four were immediately detected on angiography; 2 were initially negative on imaging. Five were treated with a pipeline embolization device, and 1 was treated with a Silk Vista Baby. Two were treated with 2 pipeline embolization devices telescopically overlapped across the pseudoaneurysm. All devices deployed successfully. No pseudoaneurysm recurrence or rebleeding occurred. No parent artery occlusion or stenosis was observed, and complete pseudoaneurysm occlusion was observed in 4 patients (in 2 patients, follow-up imaging could not be obtained). CONCLUSION/CONCLUSIONS:With proper antiplatelet regimens, flow diverter stents can be used safely to successfully treat complex acute iatrogenic injuries. Early repeat angiogram is needed when immediate postinjury imaging does not discover the point of vessel injury.

IntroductionFlow diversion with the pipeline embolization device (PED) is an effective endovascular treatment. However, the metal surface's thrombogenicity and need for dual antiplatelet therapy (DAPT) are notable limitations. Few prior studies have reported specifically on flow diverters' safety in patients with hemoglobinopathies, a population at increased risk of thrombotic and hemorrhagic complications.MethodsNatural language processing queried our institution's medical records for intracranial embolization procedures from 2014 to 2024, screening for "hemoglobinopathy," "thalassemia," and "sickle cell." Patient charts were retrospectively reviewed.ResultsSixteen procedures in 14 patients were identified in which a mean 2.0 PEDs per patient were used. Most patients were female (71.4%). Median age was 48.8 years. Five patients had sickle cell disease, two had sickle cell trait, two had sickle cell or hemoglobin C trait and alpha thalassemia minor, and five had alpha thalassemia minor. The 14 patients were treated for 20 aneurysms; four treatments covered two distinct aneurysms. Median dome size per treatment was 4.0 mm. Of the 16 aneurysm treatments, five (31.2%) treated an irregular aneurysm. Most (56.2%) treatments used multiple PEDs. All patients were discharged on DAPT after verifying effect with P2Y12 assays. Follow-up DSA, CTA, or MRA was obtained in 12/14 (85.7%) patients at a median 1.6 years. Complete occlusion was achieved in all aneurysms. Clinical follow-up was obtained in all patients at a median 2.2 years. There were no thromboembolic or hemorrhagic complications, neurological deficits, or mortalities.ConclusionPipeline embolization can safely and effectively treat patients with hemoglobinopathies.

While the Woven EndoBridge (WEB) device has transformed the treatment of wide-neck intracranial aneurysms, incomplete occlusion remains a significant challenge requiring better understanding of contributing factors. A retrospective analysis was conducted on multicenter data from patients who underwent WEB device treatment for intracranial aneurysms between January 2011 and December 2022. Using machine learning models, Cox regression, and time-stratified analyses, we evaluated factors associated with persistent incomplete occlusion, defined as non-improving Raymond-Roy Occlusion Classification grade 2 or 3 at final follow-up. Among 813 patients (607 with < 24 months follow-up, 206 with ≥ 24 months), machine learning analysis identified aneurysm height, Acom location, neck diameter, and pretreatment mRS as predictors of persistent incomplete occlusion. On Cox regression. larger aneurysm neck diameter (HR 1.13, 95% CI 1.01-1.27, p = 0.027) and height (HR 1.14, 95% CI 1.02-1.26, p = 0.017), and radial access (HR 2.68, 95% CI 1.76-4.07, p < 0.001) increased, while posterior circulation location (HR 0.56, 95% CI 0.37-0.84, p = 0.005) decreased the risk of persistent incomplete occlusion. Time-stratified analysis revealed that in short-term follow-up (< 24 months), larger aneurysm neck diameter (OR 1.28, 95% CI 1.08-1.52, p = 0.004) increased the risk of incomplete occlusion. In long-term follow-up (≥ 24 months), smoking (OR 2.69, 95% CI 1.04-7.00, p = 0.04), higher pre-treatment mRS (OR 1.78, 95% CI 1.15-2.76, p = 0.009), and immediate flow stagnation (OR 0.33, 95% CI 0.11-0.96, p = 0.04) increased, while older age (OR 0.94, 95% CI 0.90-0.98, p = 0.002) and WEB-DL (OR 0.06, p < 0.001) and SLS devices (OR 0.02, p = 0.003) decreased the risk of persistent incomplete occlusion. Aneurysm characteristics and device type significantly influence long-term WEB treatment outcomes.