Faculty Bibliography

OBJECTIVE:The objective was to evaluate the trajectories of hematoma resolution and functional improvement after middle meningeal artery embolization (MMAE) for chronic subdural hematoma (cSDH), model the temporal pattern of cSDH resolution, and identify factors associated with favorable outcomes. METHODS:This real-world multicenter retrospective study included cSDH patients treated with MMAE at 24 centers between 2019 and 2024. Hematoma thickness was measured at baseline and at follow-up intervals (1-4 weeks, 1-3 months, 3-6 months, 6-12 months, and > 12 months after embolization). Resolution patterns were modeled using exponential decay functions. Modified Rankin Scale (mRS) scores assessed functional outcomes. Good functional outcome was defined as mRS score ≤ 2. Resolution patterns were modeled using exponential decay functions to estimate time to 50% and 80% reduction. Patients were categorized as complete resolution (≥ 99%) or by quartile of the remaining distribution (substantial [73%-98%], moderate [53%-73%], partial [27%-53%], minimal [< 27%]). The primary outcome was good functional status (mRS score ≤ 2). RESULTS:The authors analyzed a total of 1781 patients with 2295 cSDHs who underwent MMAE. The mean ± SD age was 72.8 ± 12.4 years and 68.1% of patients were male. The initial mean hematoma thickness was 15.31 ± 6.53 mm, decreasing to 5.24 ± 5.91 mm at final follow-up (mean reduction 64.3% ± 42.1%). Resolution followed an exponential decay pattern, with an estimated time to 50% reduction of 1.8 months and to 80% reduction of 8.9 months. Complete resolution occurred in 1031 of 2224 patients (46.4%) with complete follow-up. The median (IQR) mRS score improved from 1 (0-3) at baseline to 0 (0-2) at > 12 months. Good functional outcomes were more common in patients with complete versus minimal resolution (68.9% vs 35.0%, p < 0.001). Achieving ≥ 73% resolution within 90 days was associated with better outcomes (good outcome in 76.9% of those with ≥ 73% resolution vs 67.3% in those without, p < 0.001). Neurological deterioration was the strongest predictor of lack of good outcome (23.7% in patients with neurological deterioration vs 82.4% without, p < 0.001). CONCLUSIONS:After MMAE for cSDH, reduction in hematoma thickness follows a predictable exponential decay pattern. Greater extent (≥ 80%) and faster timing (within 90 days) of resolution are valuable prognostic indicators. Functional outcomes improve progressively through 6-12 months after the procedure. The relationship between resolution extent and functional outcomes provides quantitative benchmarks for evaluating treatment response.

PURPOSE/OBJECTIVE:Although the Woven EndoBridge (WEB) device is increasingly used for the treatment of wide-neck intracranial aneurysms, including in the acute rupture setting, comparative evidence assessing the impact of rupture status remains limited. This study compared angiographic, safety, and clinical outcomes between ruptured and unruptured intracranial aneurysms treated with WEB. METHODS:We conducted a retrospective analysis of prospectively collected data from the multicenter cohort registry WorldWideWEB, including consecutive adult patients with intracranial aneurysms treated with the WEB. Patients were stratified into groups of ruptured and unruptured aneurysms. Propensity score matching was used to balance baseline characteristics between both groups. Retreatment rate was the primary outcome. Secondary outcomes included mRS, safety events (thromboembolic complications) and angiographic outcomes (periprocedurally and last follow-up). RESULTS:Among 1,220 patients, 342 (28.0%) presented with ruptured aneurysms. Propensity-score-matched analyses revealed no significant difference in thromboembolic complications (11.8% vs. 5.9%, p = 0.056), similar periprocedural adequate occlusion (53.3% vs. 53.8%, p > 0.9), and similar retreatment rates (11.8% (95% CI 7.8-17.6%) vs. 7.1% (95% CI 4.1-12.0%), p = 0.14); however, adequate occlusion at follow-up was lower (82.2% vs. 93.3%, p = 0.002) and functional outcomes were worse (mRS ≥ 2 in 34.1% vs. 21.9%, p = 0.012) among patients with ruptured aneurysms. CONCLUSION/CONCLUSIONS:Ruptured aneurysms demonstrated expected inferior follow-up functional and angiographic outcomes when compared with unruptured aneurysms, but no difference in retreatment rate and procedural safety. These findings support WEB as a safe and effective treatment option for appropriately selected ruptured intracranial aneurysms in routine clinical practice.

BACKGROUND:Flow diversion is effective for unruptured distal anterior cerebral artery (DACA) aneurysms, yet comparative data between the Silk Vista Baby (SVB) and Pipeline Embolization Device (PED) in this challenging territory remain scarce. METHODS:We conducted a retrospective multicenter study using the CRETA Registry, including consecutive patients with unruptured DACA aneurysms treated with SVB or PED. The primary endpoint was complete angiographic occlusion (O'Kelly-Marotta grade D). Secondary outcomes included procedural characteristics, clinical outcome (modified Rankin Scale), and complications. Overlap weighting was applied to account for non-randomized treatment allocation. Predictors of occlusion were explored using penalized logistic regression. A sensitivity analysis using a reduced five-variable model was performed to assess model robustness. RESULTS:137 patients were included (79 SVB, 58 PED). Within the PED group, devices included Pipeline Flex (n = 34), Pipeline Flex with Shield Technology (n = 14), and Pipeline Vantage with Shield Technology (n = 10). After overlap weighting, baseline characteristics were balanced; the effective sample size was 100.4. SVB procedures more often used a single device; PED frequently required multiple stents. Procedure duration was shorter with SVB. Complete occlusion was achieved in 69.6% (SVB) and 70.7% (PED) of aneurysms, with no significant difference in adjusted analysis (OR 1.32, 95% CI 0.59-2.96). Favorable clinical outcomes were observed in both groups, with acceptable and comparable complication rates. No variable, including device type, independently predicted complete occlusion, a finding confirmed in a reduced five-variable sensitivity analysis (aOR 1.04, 95% CI 0.47-2.31; p = 0.915). CONCLUSIONS:SVB and PED demonstrated comparable angiographic efficacy and clinical safety for unruptured DACA aneurysms. Despite procedural differences, mid-term occlusion rates and outcomes were similar. Device selection in this distal territory may be guided primarily by anatomical considerations and operator preference rather than expectations of differential performance.

BACKGROUND AND OBJECTIVES/OBJECTIVE:Carotid webs are an underrecognized cause of ischemic stroke in young adults and are associated with a high risk of recurrence when managed with medical therapy alone. Although carotid endarterectomy (CEA) is increasingly performed, histopathological confirmation remains infrequently reported, and the underlying pathological substrate of symptomatic carotid webs is not well defined. In this study, we present the largest pathologically confirmed series of symptomatic carotid webs treated with CEA, providing a comprehensive clinicopathological characterization and evaluation of long-term surgical outcomes. METHODS:Patients with symptomatic carotid webs were retrospectively identified from institutional databases encompassing both inpatient and outpatient encounters. Clinical features, imaging characteristics, surgical findings, and histopathological results from CEA specimens are presented. RESULTS:Among 39 patients with symptomatic carotid web, 34 underwent CEA with histopathological confirmation of the diagnosis, characterized by focal eccentric intimal fibromyxoid tissue, fibromuscular dysplasia, hyperplasia, or thickening. Notably, concurrent atheromatous changes were noted in 6 patients. All webs were located within 3 cm of the carotid bifurcation, and most (76%) were localized on the posterior wall. Competing stroke mechanisms were identified in 15% of patients. Two-thirds of patients presented with a large or medium vessel occlusion and over half received acute reperfusion therapy (intravenous thrombolysis and/or mechanical thrombectomy). Two patients experienced transient, minor cranial nerves injuries (hypoglossal nerve and marginal mandibular branch) after CEA. At a median follow-up of 29 months, no patients experienced recurrent stroke (95% CI: 0%-10%), and the median modified Rankin Scale score was 1 (0-1). CONCLUSION/CONCLUSIONS:This study supports CEA as a safe and effective therapeutic option for patients with symptomatic carotid webs and demonstrates its diagnostic value through direct histopathological confirmation. By presenting the largest pathologically validated series to date, our findings further define the vascular pathology underlying carotid webs and underscore the diagnostic value of surgical resection for definitive diagnosis.

This chapter reviews the vascular anatomy of the brainstem and posterior circulation with emphasis on clinical neurology and angiographic interpretation. Using a caudal-to-cranial approach, we describe the vertebral artery at the craniocervical junction and its key branches, including meningeal, medullary, spinal, and posterior inferior cerebellar arteries (PICA), highlighting common variants and clinically important anastamoses. We then outline basilar artery segments, pontine perforator patterns, and vertebrobasilar perforator groups, linking lesion location to characteristic neurologic syndromes. The cerebellar arteries (PICA, AICA, and superior cerebellar artery) are discussed with attention to variant origins, shared trunks, and collateral pathways that influence infarct topography. Finally, we summarize basilar tip and posterior cerebral artery (PCA) anatomy, including fetal PCA configurations, and thalamoperforator variants, such as the artery of Percheron.

BACKGROUND:The RESCUE-ICAS study (Registry of Emergent Large-Vessel Occlusion due to Intracranial Stenosis) demonstrated that patients undergoing acute stenting of intracranial atherosclerosis with large-vessel occlusion after mechanical thrombectomy had better outcomes than those undergoing mechanical thrombectomy alone. We present 2 secondary analyses of RESCUE-ICAS to evaluate intracranial stenting among patients who achieved successful reperfusion. METHODS:From a prospective observational cohort of 25 stroke centers (2022-2023), patients with acute intracranial occlusion, National Institutes of Health Stroke Scale score ≥6, and 50% to 99% residual stenosis or occlusion after endovascular thrombectomy were included. In the first analysis, we compared patients with stenting versus those without stenting from among those patients with a final modified Thrombolysis in Cerebral Infarction score of 2B-3. In the second analysis, we compared patients who underwent stenting with those who did not from among the patients with a Thrombolysis in Cerebral Infarction (TICI) score of 2B-3 before stenting. The odds of a favorable 90-day mRS (0-2) and 24-hour MRI infarct volume <30 mL were assessed using multivariable logistic regression. We also examined the rates of symptomatic ICH and death at 90 days in these cohorts. RESULTS:=0.480). CONCLUSIONS:Among both the cohort with final successful reperfusion and the cohort with initial successful reperfusion after mechanical thrombectomy alone, intracranial stenting was associated with better long-term clinical and radiographic outcomes, without higher morbidity and mortality. REGISTRATION/BACKGROUND:URL: https://www.clinicaltrials.gov; Unique identifier: NCT05403593.

BACKGROUND:Venous anatomical variants are common and generally considered normal. However, growing recognition of cerebral venous disorders (CVD) in neurological disease has prompted renewed interest in venous architecture, especially with increasing use of the internal jugular vein (IJV) as a target for outflow augmentation. Establishing baseline data on venous stenosis prevalence in an unselected population is critical for future research. This study aimed to assess the prevalence of IJV stenoses in patients undergoing neck CT angiography for unrelated indications. METHODS:We conducted a multicenter, retrospective study analyzing the venous anatomy of patients who underwent CT angiography for unrelated conditions, primarily large vessel occlusion. Stenosis was graded based on the percentage of lumen narrowing with a NASCET-style methodology, and the relationship between IJV stenosis severity and suboccipital collateral drainage was evaluated. Consecutive CT angiograms of patient were queried to map anatomical features. RESULTS:68% of the 679 total patients exhibited some degree of IJV stenosis. Severe unilateral stenosis (≥51%) was present in approximately 21% of patients, while complete or near-complete occlusion was uncommon at 8%. Bilateral high-grade stenosis was noted in 18% of patients for >50% stenosis and in only 2% of patients for >75% stenosis. A greater degree of stenosis correlated with increased suboccipital collateral vein diameter (p = 0.0025). CONCLUSION/CONCLUSIONS:IJV stenosis is common on CT angiography performed for non-venous indications with a correlation between the degree of stenosis and suboccipital collateral vein diameter. The clinical significance of these findings and its possible contribution to CVD requires further prospective investigation.

BACKGROUND:The Society of Vascular and Interventional Neurology (SVIN) Guidelines and Practice Standards Committee issues Brief Practice Updates to provide concise, evidence-based recommendations and suggestions on focused topics relevant to vascular and interventional neurology. Currently, there is limited published guidance on the technical performance and interpretative parameters of cerebral digital subtraction angiography for the determination of cerebral circulatory arrest in patients being evaluated for brain death/death by neurological criteria. In this Brief Practice Update, we present consensus-based suggestions for standardizing the performance, interpretation, and application of digital subtraction angiography in this context. METHODS:This Brief Practice Update was developed using the SVIN Standards and Parameters for Guideline Development in the classification of evidence and Class of Recommendation when evidence is available and Expert Opinion recommendation when evidence is lacking. The Guidelines and Practice Standards committee convened a multidisciplinary writing group to establish key clinical questions and develop a survey assessing Expert Opinion on the role of digital subtraction angiography in cerebral circulatory arrest determination. Survey items addressed technical considerations, interpretation criteria, and clinical integration. Iterative refinement was achieved through group consensus, and the final survey was distributed to a panel of experts in neurointervention and neurocritical care. The SVIN Guidelines and Practice Standards Quality Committee reviewed the findings for adherence to SVIN's internal evidence evaluation guidelines before submission to the SVIN board for societal endorsement. RESULTS:Evidence was evaluated by the writing group when available, and Expert Opinion was assessed using survey results. Suggested recommendations follow the established SVIN guideline framework for Class of Recommendation and Level of Evidence, with an Expert Opinion endorsement category for areas lacking high-quality evidence at the time of publication. CONCLUSIONS:This update standardizes how to perform, interpret, and report digital subtraction angiography when used to assess cerebral circulatory arrest in brain death/death by neurological criteria evaluations, aiming to improve reproducibility across centers. It provides a structured framework to improve consistency and reliability among practitioners performing and interpreting cerebral angiography in this setting.

PURPOSE/OBJECTIVE:Rescue stenting (RS) can achieve durable recanalization in cases of acute large vessel occlusion due to underlying intracranial artery stenosis (ICAS), but its clinical effects may be influenced by procedural factors. This study aimed to evaluate whether the severity of stenosis affects the outcomes after RS. METHODS:In this multicenter retrospective study, patients with acute middle cerebral artery occlusion and underlying ICAS were divided into two groups based on the treatment they received: mechanical thrombectomy (MT) + RS (n = 172) or MT-only (n = 131). Inverse probability of treatment weighting was used to balance baseline characteristics. We systematically evaluated stenosis thresholds from 40% to 90% to identify the optimal cutoff that best differentiated treatment effects on the 90-day modified Rankin Scale (mRS) score and safety outcomes, including symptomatic intracranial hemorrhage (sICH). RESULTS:A stenosis severity of 75% was identified as the optimal cutoff for effect modification. While RS improved recanalization rates overall, its effect on the 90-day mRS score was beneficial only in patients with > 75% stenosis compared to MT-only (Average Treatment Effect (ATE) -0.98, 95% CI -1.73 to -0.22; p = 0.01). In contrast, it showed a detrimental effect in those with < 75% stenosis (ATE 1.08, 95% CI 0.32 to 1.83; p = 0.005). Furthermore, RS increased the rate of sICH regardless of ICAS severity. CONCLUSIONS:The clinical benefit of RS is contingent on the underlying stenosis severity, providing favorable outcomes in patients with high-grade stenoses only. ICAS severity should also be considered for treatment decisions, though these findings require validation in prospective controlled studies.