Low-profile mechanical thrombectomy devices for large vessel occlusion in pediatric ischemic stroke.

BACKGROUND: Mechanical thrombectomy (MT) is a well-established treatment modality for large vessel occlusion (LVO) in adults, but there are limited data in the pediatric population. The rarity of the condition makes prospective trial design difficult, and therefore evaluation of MT devices and outcomes is sparse. In pediatric LVO cases, some newer devices may be appropriate for use in revascularization procedures. Furthermore, illustrative specific device-access combinations have rarely been presented in young patients under the age of 5 years. METHODS: This was a single institution experience in intracranial MT procedures for pediatric acute ischemic stroke (AIS). A given procedure was included if there was an attempt at MT between 2015 and 2023. RESULTS: Sixteen endovascular procedures were performed in 15 patients with AIS, with a mean age of 7.4 years; eight patients were <5 years of age. MT was attempted in 15/16 (93.7%) procedures, including 11 (73.3%) in the anterior circulation and four (26.7%) in the posterior circulation; one case recanalized after medical treatment. The most common MT techniques were combined aspiration with a stentriever (n=10, 66.7%) and aspiration alone (n=3, 20%). Traditional stentrievers (4-6 mm) were used in seven cases and low-profile stentrievers in four cases. Improved reperfusion was achieved in all low-profile stentriever cases. Reperfusion of modified Thrombolysis in Cerebral Infaction ≥2b was obtained in 73.3% of cases, including 72.7% of those in which a stentriever was used. CONCLUSIONS: Low-profile thrombectomy devices may achieve similar revascularization results to other approaches in challenging clinical scenarios observed in younger children.

Infantile dural arteriovenous fistula: a reconsideration.

BACKGROUND: Infantile-type dural arteriovenous shunts (IDAVS) are rare and heterogeneous vascular lesions, complicating their classification and management. The current tripartite classification of pediatric dural arteriovenous shunts (DAVS) into dural sinus malformation, infantile-type, and adult-type, does not stand up to scrutiny, given the variable presentations of the latter two types in children. We estimate the prevalence of IDAVS and evaluate the long term outcomes after endovascular treatment (EVT). METHODS: A retrospective review of a pediatric cerebrovascular database between 2006 and 2023 was conducted. Clinical and radiographic data were analyzed to evaluate the presentation and long term outcomes of IDAVS. RESULTS: IDAVS were identified in 8 (0.5%) of 1463 patients, with mean age at diagnosis of 34.7 months; male infants comprised 62.5%. The most common clinical presentations included macrocephaly (37.5%), seizures (25%), and dilated scalp veins (25%). EVT was performed in 87.5% of cases, averaging 5.8 procedures per patient. Radiographic obliteration was observed in 28.6%. Good clinical outcomes (modified Rankin Scale score of ≤2) were achieved in 85.7%. Our findings showcased discrepancies and limitations in the current classification of pediatric DAVS, prompting a re-evaluation. CONCLUSION: IDAVS accounted for a small proportion of pediatric cerebrovascular pathologies, with markedly heterogeneous presentations. Stepwise selective embolization was associated with favorable outcomes, and is recommended over an aggressive approach with the goal of complete angiographic obliteration. Our proposed revised classification system bifurcates pediatric DAVS into dural sinus malformations and all other DAVS that are manifest in children, thereby enhancing diagnostic clarity and therapeutic approaches.

Management of Choroid Plexus Tumors and the Benefit of Preoperative Embolization in Pediatric Patients: Report of 46 Cases from a Single Institution.

OBJECTIVE: Optimal choroid plexus tumor (CPT) treatment involves gross total resection; however, intraoperative hemorrhage risk remains significant given tumor vascularity. This study describes pediatric CPT management and identifies patients most likely to benefit from preoperative embolization. METHODS: CPTs resected from 1997 to 2021 were included. The characteristics of embolized patients were compared to nonembolized patients; nonembolized patients were further stratified based on open vascular control-pedicle feeder ligation versus no pedicle ligation prior to tumor debulking. Statistical analyses identified factors associated with estimated blood loss (EBL), transfusion, length of stay, and complications. RESULTS: Among the 46 CPT cases identified, 98% achieved gross total resection, and 15% received embolization. Embolized patients were younger, smaller, and had larger tumors compared to nonembolized patients (median: 0.8 vs. 2.1 years; 9.3 vs. 14.4 kg; 91.08 vs. 5.5 cm3). Transfused patients were similarly younger and smaller (P < 0.05) than nontransfused patients. Among nonembolized patients, open vascular control was achieved in smaller tumors (<13 cm3) with significantly lower EBL (P = 0.002). Higher EBL was observed in patients with larger tumors, hydrocephalus, transependymal edema, vomiting, lethargy, and developmental regression (all P < 0.05). Patients with lethargy had longer hospital stays and a higher likelihood of postoperative complications (P < 0.05). There were no significant differences in complication rates between the embolization and nonembolization groups. CONCLUSIONS: Despite higher surgical risk profiles, embolized patients had similar complication rates and postoperative hydrocephalus management as nonembolized patients. Embolization was particularly beneficial in patients at high risk for surgical morbidity, such as those <2 years, weighing <10 kg, and with a tumor volume >15 cm3.

Posterior cerebral territory ischemia in pediatric moyamoya: Surgical techniques and long-term clinical and radiographic outcomes.

PURPOSE: To describe a surgical technique for posterior cerebral revascularization in pediatric patients with moyamoya arteriopathy. Here, we describe the clinical characteristics, surgical indications, operative techniques, and clinical and radiographic outcomes in a series of pediatric patients with moyamoya disease affecting the posterior cerebral artery (PCA) territory. METHODS: A retrospective single-center series of all pediatric patients with moyamoya disease who presented to our institute between July 2009 through August 2019 were reviewed. The clinical characteristics, surgical indications, operative techniques, and long-term clinical and radiographic outcomes of pediatric moyamoya patients with PCA territory ischemia were collected and analyzed. RESULTS: A total of 10 PCA revascularization procedures were performed in 9 patients, 5 female, ages 1 to 11.1 years (average 5.2 years). Complications included 1 stroke, with no infections, hemorrhages, seizures, or deaths. One patient had less than 1 year of radiographic and clinical follow-up. In 8 of 9 patients with at least 1 year of radiographic follow-up, there was engraftment of surgical vessels present in all cases. No new strokes were identified on long-term follow-up despite the radiographic progression of the disease. In the 8 cases available for analysis, the average follow-up was 50.8 months with a range of 12 to 117 months. CONCLUSIONS: PCA territory ischemia in patients with progressive moyamoya disease can be surgically treated with indirect revascularization. Here, we describe our experience with PCA revascularization procedures for moyamoya disease, including pial pericranial dural (PiPeD) revascularization and pial synangiosis utilizing the occipital artery. These surgical options may be useful for decreasing the risk of stroke in pediatric moyamoya patients with severe posterior circulation disease.

Direct Transverse Sinus Puncture for Transvenous Coil Embolization of Vein of Galen Malformations: Innovating Existing Techniques.

BACKGROUND AND IMPORTANCE: Vein of Galen malformations (VOGMs) are complex arteriovenous malformations in neonates and young children. Recent advances in endovascular interventions have drastically improved treatment and clinical outcomes in what was previously high-morbidity, high-mortality disease. The high-flow shunt pathophysiology in VOGMs can lead to dynamic changes in the malformation angioarchitecture, and over time patients can develop jugular bulb stenosis. In the setting of inaccessible transvenous access to the malformation for endovascular embolization in cases where transarterial embolization is inadequate, a combined surgical and endovascular technique must be used. We present the first successful modern-day application of direct puncture through transverse sinus for transvenous embolization of a VOGM. CLINICAL PRESENTATION: We present 2 unique cases of complex VOGM malformations in patients who had previously undergone staged endovascular embolization for reduction of flow within the malformation. On follow-up, in both cases, there was development of severe sigmoid sinus and jugular bulb stenosis, increasing intracranial venous congestion and causing marked clinical deterioration. The stenosis prevented traditional transvenous access and treatment. We describe a direct puncture transverse sinus access using a burr hole approach for endovascular transvenous embolization in both cases with successful clinical outcomes. CONCLUSION: Direct access using burr hole craniotomy to the transverse sinus for transvenous endovascular embolization is a safe approach in the setting of severe jugular bulb stenosis for treatment of VOGMs. This technique can be done efficiently to achieve complete flow elimination in the malformation, in cases where that is called for, without significant risks or complications related to the approach.

Understanding development of jugular bulb stenosis in vein of galen malformations: identifying metrics of complex flow dynamics in the cerebral venous vasculature of infants.

Introduction: Computational fluid dynamics (CFD) assess biological systems based on specific boundary conditions. We propose modeling more advanced hemodynamic metrics, such as core line length (CL) and critical points which characterize complexity of flow in the context of cerebral vasculature, and specifically cerebral veins during the physiologically evolving early neonatal state of vein of Galen malformations (VOGM). CFD has not been applied to the study of arteriovenous shunting in Vein of Galen Malformations but could help illustrate the pathophysiology of this malformation. Methods: Three neonatal patients with VOGM at Boston Children's Hospital met inclusion criteria for this study. Structural MRI data was segmented to generate a mesh of the VOGM and venous outflow. Boundary condition flow velocity was derived from PC-MR sequences with arterial and venous dual velocity encoding. The mesh and boundary conditions were applied to model the cerebral venous flow. We computed flow variables including mean wall shear stress (WSSmean), mean OSI, CL, and the mean number of critical points (nCrPointsmean) for each patient specific model. A critical point is defined as the location where the shear stress vector field is zero (stationary point) and can be used to describe complexity of flow. Results: The division of flow into the left and right venous outflow was comparable between PC-MR and CFD modeling. A high complexity recirculating flow pattern observed on PC-MR was also identified on CFD modeling. Regions of similar WSSmean and OSImean (<1.3 fold) in the left and right venous outflow channels of a single patient have several-fold magnitude difference in higher order hemodynamic metrics (> 3.3 fold CL, > 1.7 fold nCrPointsmean). Specifically, the side which developed JBS in each model had greater nCrPointsmean compared to the jugular bulb with no stenosis (VOGM1: 4.49 vs. 2.53, VOGM2: 1.94 vs. 0, VOGM3: 1 vs. 0). Biologically, these regions had subsequently divergent development, with increased complexity of flow associating with venous stenosis. Discussion: Advanced metrics of flow complexity identified in computational models may reflect observed flow phenomena not fully characterized by primary or secondary hemodynamic parameters. These advanced metrics may indicate physiological states that impact development of jugular bulb stenosis in VOGM.

World federation of interventional and therapeutic neuroradiology (WFITN) federation assembly neurointerventional surgery safety checklist.

Over the last 10 years, there has been a rise in neurointerventional case complexity, device variety and physician distractions. Even among experienced physicians, this trend challenges our memory and concentration, making it more difficult to remember safety principles and their implications. Checklists are regarded by some as a redundant exercise that wastes time, or as an attack on physician autonomy. However, given the increasing case and disease complexity along with the number of distractions, it is even more important now to have a compelling reminder of safety principles that preserve habits that are susceptible to being overlooked because they seem mundane. Most hospitals have mandated a pre-procedure neurointerventional time-out checklist, but often it ends up being done in a cursory fashion for the primary purpose of 'checking off boxes'. There may be value in iterating the checklist to further emphasize safety and communication. The Federation Assembly of the World Federation of Interventional and Therapeutic Neuroradiology (WFITN) decided to construct a checklist for neurointerventional cases based on a review of the literature and insights from an expert panel.

Pulmonary Hypertension in Infants and Children with Vein of Galen Malformation and Association with Clinical Outcomes.

OBJECTIVE: To assess the extent and resolution of pulmonary hypertension (PH), cardiovascular factors, and echocardiographic findings associated with mortality in infants and children with vein of Galen malformation (VOGM). STUDY DESIGN: We performed a retrospective review of 49 consecutive children with VOGM admitted to Boston Children's Hospital from 2007 to 2020. Patient characteristics, echocardiographic data, and hospital course were analyzed for 2 cohorts based on age at presentation to Boston Children's Hospital: group 1 (age ≤60 days) or group 2 (age >60 days). RESULTS: Overall hospital survival was 35 of 49 (71.4%); 13 of 26 (50%) in group 1 and 22 of 23 (96%) in group 2 (P < .001). High-output PH (P = .01), cardiomegaly (P = .011), intubation (P = .019), and dopamine use (P = .01) were significantly more common in group 1 than group 2. Among patients in group 1, congestive heart failure (P = .015), intubation (P < .001), use of inhaled nitric oxide (P = .015) or prostaglandin E1 (P = .030), suprasystemic PH (P = .003), and right-sided dilation were significantly associated with mortality; in contrast, left ventricular volume and function, structural congenital heart disease, and supraventricular tachycardia were not associated. Inhaled nitric oxide achieved no clinical benefit in 9 of 11 treated patients. Resolution of PH was associated with overall survival (P < .001). CONCLUSIONS: VOGM remains associated with substantial mortality among infants presenting at ≤60 days of life owing to factors associated with high output PH. Resolution of PH is an indicator associated with survival and a surrogate end point for benchmarking outcomes.

Heart Failure Following Sinus Venosus Defect Closure in a Patient With Vein of Galen Malformation.

This case concerns an 18-month-old with masked congestive heart failure (CHF) from an unrepaired vein of Galen malformation and superior sinus venosus defect who progressed to severe, refractory CHF following superior sinus venosus defect repair. Partial transvenous coil embolization of a very-high-risk vein of Galen malformation resolved CHF symptoms. (Level of Difficulty: Advanced.).

Neurosurgical outcomes of pediatric cerebral venous sinus thrombosis following acute mastoiditis: a systematic review and meta-analysis.

OBJECTIVE: Neurosurgical outcomes are not well defined in the management of pediatric patients with cerebral venous sinus thrombosis (CVST) following acute mastoiditis. Specific notable sequelae are otogenic (otitic) hydrocephalus and CVST management. Correspondingly, the aim of this study was to integrate the currently published metadata to summarize these outcomes. METHODS: Electronic searches were performed using the Ovid Embase, PubMed, Scopus, and Cochrane databases from inception to November 2022 following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Cohort-level data were then abstracted for analysis for appropriate pediatric patients. Outcomes were pooled by random-effects meta-analyses of proportions where possible. RESULTS: Twenty-three study cohorts describing 312 pediatric patients with otogenic CVST were included. At a cohort level, the median patient age was 6 years among 181 boys (58%) and 131 girls (42%). Modeling indicated papilledema at presentation in 46% of cases (95% CI 30%-62%). Regarding management, antibiotics were applied universally in all cases, mastoidectomy or other otologic surgery was performed in 91% (95% CI 82%-98%), and prophylactic anticoagulation was administered in 86% (95% CI 75%-95%). There was only 1 case (0.3%) of postprocedural intracranial hemorrhage, and there were no deaths reported among all studies. Although diagnostic lumbar puncture was performed in 14% (95% CI 3%-28%) at presentation, clinical otogenic hydrocephalus was ultimately suspected in 31% (95% CI 14%-49%), and acetazolamide was given in 65% (95% CI 35%-91%) overall. There were 10 cases (3%) that proceeded to permanent CSF diversion in the form of ventricular shunting. At a median follow-up of 8 months among all studies, the venous sinus was completely recanalized in 67% (95% CI 53%-79%). CONCLUSIONS: Most CVSTs following acute mastoiditis will recanalize with the standard use of antibiotics, otologic surgery, and anticoagulation, with minimal symptomatic hemorrhage risk. However, an appreciable proportion of these patients will develop symptomatic otogenic hydrocephalus, and it is imperative that the appropriate surveillance and workup is performed to fully optimize patient outcomes long-term. The possible need for permanent CSF diversion should be recognized.

Magnetic Resonance Imaging/Angiography Versus Catheter Angiography for Annual Follow-up of Pediatric Moyamoya Patients: A Cost Outcomes Analysis.

BACKGROUND: Digital subtraction angiography (DSA) assesses revascularization in pediatric moyamoya patients after surgery, but MRI and angiography (MRI/A) may provide comparable data. OBJECTIVE: To evaluate DSA and MRI/A with respect to clinical utility in postoperative follow-up, complication profile, and relative cost at 1 year. METHODS: All pediatric moyamoya patients who received bilateral indirect revascularization between 2011 and 2020 were retrospectively reviewed at 1 institution. Patients who underwent MRI/A-only, DSA-only, or both after 1 year were compared. RESULTS: Eighty-two patients were included. At 1 year, patients who underwent either MRI/A (n = 29) or DSA (n = 40) had no significant differences in detection rate of new at-risk hypovascular territories (6.9% vs 2.5%, P = .568) or need for subsequent revascularization beyond the mean 40 ± 24-month follow-up period (3.4% vs 5.0%, P > .9). Among patients who underwent both MRI/A and DSA (n = 13), both studies identified the same at-risk territories. No patients experienced MRI/A-related complications, compared with 3 minor DSA-related complications. The use of MRI/A yielded a 6.5-fold reduction in cost per study vs DSA at 1 year. CONCLUSION: Using DSA to follow moyamoya patients after indirect revascularization is generally safe but associated with a low rate of minor complications and a 6.5-fold greater financial cost relative to MRI/A. These data support changing practice to eliminate the use of DSA when following routine bilateral moyamoya cases in the absence of clinical symptoms or specific concerns. Using MRI/A as the primary postoperative follow-up modality in this select population provides noninferior care and greater patient access, while reducing cost and potentially decreasing risk.

Overcoming roadblocks in clinical innovation via high fidelity simulation: use of a phantom simulator to achieve FDA and IRB approval of a clinical trial of fetal embolization of vein of Galen malformations.

BACKGROUND: Vein of Galen malformation (VOGM) is a rare, life-threatening vascular malformation in neonates and is treated with embolization. However, even at the most experienced centers, patients face high mortality and morbidity. In utero treatment options have been limited by lack of animal models or simulations. OBJECTIVE: To create a novel ultrasound phantom simulator for a preclinical feasibility study of in utero fetal intervention for VOGM. METHODS: Novel phantoms were designed and built in two configurations of spherical and windsock shape from cryogel material to mimic the salient vasculature of the fetal VOGM, based on real-patient fetal MR imaging dimensions. Critical anatomy was realistically mimicked within this model and transtorcular ultrasound-guided coil deployment was simulated. Each phantom model was assessed before and after treatment to evaluate coil mass deposition within the target. RESULTS: The two phantoms underwent pretreatment T2-weighted MR imaging assessment, ultrasound-guided embolization, post-treatment MR and fluoroscopic imaging, and visual inspection of the sliced phantoms for target embolization verification. Postoperative MR scans confirmed realistic compact deposition of the coil masses within the central cavity. Phantom embolization results were submitted as part of the institutional review board and US Food and Drug Administration investigative device exemption approval for a first-in-humans clinical trial of fetal intervention for VOGM. CONCLUSIONS: A phantom simulator for fetal intervention of VOGM produces lifelike results during trial interventions, removing obstacles to feasibility and safety evaluations, typically precluded by non-availability of appropriate animal models. The study provides a proof of concept for potentially wider applications of medical simulation to enable novel procedural advancements in neurointerventions.

Standard umbilical artery catheters used as diagnostic and neurointerventional guide catheters in the treatment of neonatal cerebrovascular malformations.

BACKGROUND: Vascular access in neonates is limited by the small size of the femoral artery and the risk of complications, including thrombosis and limb ischemia. Although umbilical artery access has been described, previous reports detail exchange of the umbilical artery catheter (UAC) for a conventional arterial sheath, which can be difficult and cumbersome. We aim to describe direct use of the UAC as the sheath and guide catheter in neonatal patients requiring endovascular treatment for life-threatening intracranial arteriovenous shunts. METHODS: We reviewed all cases between 2016 and 2021 of neonatal intervention using a direct UAC approach. We describe our technique of utilizing UACs for cerebral angiography and neurointerventions in newborns without catheter exchange, allowing for repeated, straightforward endovascular access in neonates across multiple interventions. RESULTS: Seven consecutive neonates underwent endovascular neurointerventional procedures for the treatment of life-threatening, high-flow arteriovenous shunts using a direct UAC access technique without procedural morbidity. Five of seven patients underwent more than one procedure in the neonatal period, between day 1 and day 10 of life. CONCLUSIONS: Use of the UAC itself as a diagnostic catheter for cerebral angiography or as a guide catheter for neurointerventions greatly facilitates endovascular interventions in newborns and is ideal for patients requiring multiple interventions in the neonatal period. This technique helps to mitigate the risk of neonatal femoral artery access and its complications, including thrombosis, dissection, spasm, stenosis, and limb ischemia.

Percutaneous transuterine fetal cerebral embolisation to treat vein of Galen malformations at risk of urgent neonatal decompensation: study protocol for a clinical trial of safety and feasibility.

INTRODUCTION: Although endovascular techniques have improved outcomes in vein of Galen malformations (VOGM), there is still a high rate of morbidity and mortality, particularly among cases with decompensation in the neonatal period. The dimension of the draining venous sinus on fetal imaging correlates with the risk of neonatal decompensation. In fetuses within this high-risk group who do not have end-organ injury, there is a theoretical therapeutic opportunity to reduce the arteriovenous shunt before the normal physiological changes of birth precipitate decompensation. This study investigates the safety and potential benefit of treating a VOGM in utero, which has not been previously studied. METHODS AND ANALYSIS: This study aims to enroll 20 subjects: pregnant women with a fetus harbouring a high-risk VOGM (defined on MRI by a narrowest medial-lateral width greater than 8 mm in the draining venous sinus). Unfortunately, the subset of fetuses with in utero end-organ injury is ineligible, because the late stage of pathology is not amenable to recovery from a cerebrovascular intervention, likely not even in utero. This study aims to alter the physiology before such developments accrue.At or after 23 weeks of gestation, a transuterine transposterior fontanelle needle puncture to the torcular allows ultrasound-guided deployment of coils to embolise the draining venous malformation.This study has 97.5% power to detect major safety events at 30% or greater, and 80% power to detect a reduction in the rate of neonatal intervention from 80% to 30%. In the staged study design, an interval evaluation after 11 patients invokes study termination if safety events occur above the allowed threshold. ETHICS AND DISSEMINATION: The institutional review boards at Mass General Brigham and Boston Children's Hospital (BCH) reviewed and approved this protocol. The BCH Department of Radiology and a patient family philanthropic donation fund this study. The trial results will be published in peer-reviewed journals and presented at scientific conferences. TRIAL REGISTRATION NUMBER: NCT04434729.

Cerebrospinal fluid leak in epidural venous malformations and blue rubber bleb nevus syndrome.

OBJECTIVE: Clinical manifestations of blue rubber bleb nevus syndrome (BRBNS) and multifocal venous malformation (MVM) vary depending on the location of the lesions. The aim of this study was to assess the risk of developing CSF leaks in patients with epidural venous malformations (VMs). METHODS: The authors retrospectively investigated the relationship between the development of a CSF leak and the presence of epidural VMs. RESULTS: Nine patients (5 females) had epidural VMs and presentation that was confirmatory or suggestive of a CSF leak: 4 had BRBNS, 4 had MVMs, and 1 had a solitary VM. Of 66 patients with BRBNS, clinical and imaging features of CSF leak were noted in 3 (4.5%) with epidural VMs at the age of 11-44 years. A fourth patient had suggestive symptoms without imaging confirmation. An epidural blood patch was ineffective in 2 patients, both with more than one source of leakage, requiring surgical repair or decompression. Symptomatic downward displacement of the cerebellar tonsils was noted in 3 patients with MVM and 1 with a solitary VM; 3 required surgical decompression. CONCLUSIONS: These findings suggest an increased risk of CSF leak in patients with epidural VM, including BRBNS, MVMs, and solitary VMs. Awareness of the association between epidural VM and CSF leakage may facilitate earlier diagnosis and therapeutic intervention.