Vein of Galen aneurysmal malformation-clinical and angiographic spectrum with management perspective: an institutional experience

Use of a mini balloon microcatheter to facilitate penetration of fine vascular networks and curative embolization in vein of Galen malformations

Background Patients with vein of Galen malformations (VOGMs) can develop fine angiogenic networks with fistulous connections to the precursor of the vein of Galen. In these cases, transarterial embolization (TAE) with liquid embolic agents (LEAs) is challenging due to reflux in the pedicle leading to the network, causing poor penetration. Transvenous approaches carry a risk of hemorrhage from pathologic vasculature. Dual-lumen balloon microcatheters like the Scepter Mini (Microvention, Aliso Viejo, CA) improve distal pedicle access, preventing reflux. Objective Here, we report on the use of the Scepter Mini for TAE of angiogenic VOGM. Methods A single-institution retrospective chart review identified all VOGMs treated with Scepter Mini microcatheters. Clinical data, angioarchitecture, and technical parameters were reviewed. Results 17 Scepter Mini catheters were used in 12 embolization procedures of 7 patients with VOGM at a median age of 2.1 years. Patients presented with hydrocephalus (100%) and gross motor and speech delays (57.1%). Networks developed extra-axially into the subependymal zone fed by posterior choroidal, posterior cerebral, and thalamoperforator arteries. Posterior choroidal branches (n=7/17, 41.2%) were most frequently catheterized to achieve distal access to the network. Embolization with Onyx-18 and significant network penetration occurred in 17/17 uses. Near tip entrapment with LEA cast displacement occurred in 1/17 uses. Another patient experienced postprocedural intraventricular hemorrhage requiring a third ventriculostomy without permanent neurologic deficit. Conclusion The Scepter Mini provided excellent distal access with penetration to the fistula and extra-axial network reduction with few complications. The Scepter Mini provides a means for successful treatment of technically challenging angiogenic VOGM.

Vein of Galen aneurysmal malformation: does size affect outcome?

PURPOSE

To validate a semiautomated method for segmenting vein of Galen aneurysmal malformations (VGAM) and to assess the relationship between VGAM volume and other angioarchitectural features, cardiological findings, and outcomes.

METHODS

In this retrospective study, we selected all subjects with VGAM admitted to the Gaslini Children's Hospital between 2009 and 2022. Clinical data were retrieved from electronic charts. We compared 3D-Slicer segmented VGAM volumes obtained by two independent observers using phase-contrast MR venography to those obtained with manual measurements performed on T2-weighted images. The relationship between VGAM volumes and clinical and neuroimaging features was then explored.

RESULTS

Forty-three subjects with VGAM (22 males, mean age 6.56 days) were included in the study. Manual and semiautomated VGAM volumes were well correlated for both readers (r = 0.86 and 0.82, respectively). Regarding reproducibility, the inter-rater interclass correlation coefficients were 0.885 for the manual method and 0.992 for the semiautomated method (p < 0.001). The standard error for repeated measures was lower for the semiautomated method (0.04 versus 0.40 of manual method). Higher VGAM volume was associated with superior sagittal sinus narrowing, jugular bulb stenosis, and aqueductal stenosis (p < 0.05). A weak correlation was found between VGAM volume and straight sinus dilatation (r = 0.331) and superior sagittal sinus index (r =  - 0.325). No significant associations were found with cardiac findings, post-embolization complications, and outcome (p > 0.05).

CONCLUSIONS

Semiautomated VGAM volumetry is feasible and reliable with improved reproducibility compared to the manual method. VGAM volume is not a prognostic factor for clinical outcome, but it is related to other venous findings with potential hemodynamic effects.

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.

Rapid ventricular overdrive pacing and other advanced flow-control techniques for the endovascular embolization of vein of galen malformations

Endovascular embolization is the primary strategy in the management for vein of Galen malformations (VOGM). However, despite significant advances in endovascular embolization technologies and techniques, VOGMs remain very technically challenging lesions largely due to the high-flow arteriovenous shunts present in these malformations. A variety of advanced flow-control techniques can be implemented to mitigate the risk of venous escape and increase the safety and efficacy of endovascular treatment. These techniques include regionally targeted strategies (transvenous embolization and balloon-assisted transarterial embolization) and global flow-control methods (pharmacologic cardiac arrest and rapid ventricular overdrive pacing). Each of these strategies are associated with unique advantages and disadvantages, highlighting the importance of a patient-specific approach when treating these challenging lesions.

Transvenous embolization of vein of galen aneurysmal malformations with coils as a final procedure for cure: A single-institution experience of 18 years

INTRODUCTION

Staged, transarterial embolization (TAE) is currently considered the gold standard for the treatment of vein of Galen aneurysmal malformation (VGAM); however, as transarterial access becomes restricted, further staged TAE may become ineffective or carry an increased risk of hemorrhagic or ischemic stroke when attempting complete obliteration.

OBJECTIVE

To describe the first consecutive, retrospective series of VGAM treated with transvenous embolization (TVE) with coils alone, as the final treatment in staged endovascular therapy, at a single institution between January 2004 and September 2021.

RESULTS

A total of 10 patients with a median age of 5.5 (IQR: 9.25) years were treated with coiling TVE. Patients were treated with a median number of 5 (IQR: 2.75) TAEs prior to the final TVE treatment. Complete or near-complete immediate angiographic obliteration was achieved in eight patients. Immediate post-procedural (within 48 h) hemorrhagic complications were noted in two patients (20%), one of whom passed away while the second suffered from hemiparesis. Stereotactic radiosurgery was performed in two patients with incomplete obliteration after TVE. The median follow-up time after TVE was 17 (IQR: 9) months. At long-term follow up (17 months) for the remaining nine patients, all VGAMs were completely obliterated. Long-term clinical deterioration compared to pre-TVE was noticed in one case.

CONCLUSION

Transvenous coil embolization is a technically feasible but risky option, as a final-stage treatment for cure of VGAMs with restricted trans-arterial access. Although TVE with coils remains an effective therapeutic modality, we recommend continuing investigation of safer TVE techniques to achieve cure.

Fine, Vascular Network Formation in Patients with Vein of Galen Aneurysmal Malformation

BACKGROUND AND PURPOSE

A vein of Galen aneurysmal malformation is known to present with recruitment of dural feeders and, in our cohort, a fine, vascular network formation. The vessels we have observed differ from dural vascular recruitment in that they produce a hairlike, collateral network of vessels. We reviewed treatment courses of vein of Galen aneurysmal malformation treatments in a series of 36 cases that displayed a fine, vascular network formation.

MATERIALS AND METHODS

We retrospectively analyzed 36 cases of vein of Galen aneurysmal malformation, including tectal/thalamic AVMs, treated at our center from January 2004 to September 2021, and reviewed fine, vascular network formations in the subarachnoid space and subependymal zone alongside the vein of Galen aneurysmal malformation.

RESULTS

Patients at first endovascular treatment ranged from neonates to 157 months (median age, 4.3 months). Patients with preinterventional fine, vascular network formations were significantly older at the initial angiogram than patients with postinterventional fine, vascular network formations (P < .05). On average, for 20 control choroidal/mural vein of Galen aneurysmal malformations whose treatment course had been completed and in which no plexiform network was visualized, a mean of 2.63 (SD, 1.64) treatments were required to achieve a radiographic cure. For the 36 choroidal/mural vein of Galen aneurysmal malformations whose treatment course had been completed and in which a fine, vascular network formation was visualized, a mean of 5.94 (SD, 2.73) treatments were required to achieve a radiographic cure (P < .01).

CONCLUSIONS

Development of a fine, vascular network formation is an acquired and reversible phenomenon that differs from typical dural vessel recruitment, given the hairlike nature of the network and its rapid onset postinterventionally. It typically resolves after completion of treatment, and this resolution correlates with closure of the vein. We recommend that neurointerventionalists avoid delays in treatment wherever possible to reduce the likelihood of a fine, vascular network formation.

Role of endovascular embolisation for curative treatment of intracranial non-Galenic pial arteriovenous fistula

Background and purpose

The safety and effectiveness of endovascular treatment for non-Galenic pial arteriovenous fistula (NGPAVF) is inadequately known. The aim of this study is to explore the role of endovascular embolisation for curative treatment of NGPAVF.

Materials and methods

Patients with NGPAVF underwent endovascular treatment from January 2011 to November 2019 in our institution were retrospectively reviewed. Demographics, clinical information, treatment details and clinical outcomes were collected. Factors associated with clinical outcomes were statistically analysed.

Results

Twenty patients were included, with a total of 22 (2 patients have 2 fistulas) lesions. A total of 25 procedures were performed and 5 patients underwent 2 procedures. Follow-up ranged from 3 to 84 months (mean=34.5 months). Thirteen (59.1%) lesions in 12 (60.0%) patients acquired immediate occlusion after initial treatment (immediately occluded group) and follow-up confirmed the complete obliteration. A total of 17 (77.3%) lesions in 15 (75.0%) patients were cured at last follow-up. The maximal diameter of feeding arteries (p=0.04) and the maximal diameter of the varix (p=0.01) in immediately occluded group was smaller than non-immediately occluded group. The number of feeding artery (p=0.004) and the maximal diameter of the varix (p<0.001) were much smaller in curative group than non-curative group. Seven patients suffered procedure-related complications. No patients had an increased Modified Rankin Scale (mRS) and all patients had favourable clinical outcome (mRS ≥2) at last follow-up.

Conclusions

Endovascular therapy plays an important role in curative treatment of NGPAVF. Patients with less feeding arteries and small varix may be easier to be cured by endovascular embolisation.

Pediatric intracranial arteriovenous shunts: Advances in diagnosis and treatment

Pediatric intracranial arteriovenous shunts (IAVSs) comprise a wide range of lesions, including pial arteriovenous malformation (AVM) and arteriovenous fistula (AVF), dural arteriovenous fistula (DAVF) and vein of Galen aneurysmal malformation (VGAM). We provide an overview of pediatric IAVSs, encompassing both diagnosis and endovascular treatment. We include references from pertinent literature and representative cases from our hospital. Pediatric IAVS are frequently associated two broader conditions, such as capillary malformation-arteriovenous malformation (CM-AVM) and hereditary hemorrhagic telangiectasia (HHT). These conditions and the associated genetic mutations have only recently been described. Their impact on the brain will be different in the prenatal period, in neonates, in infants, and in children, with variable symptoms according to each age group and the current strategies of endovascular treatment in the management of these vascular lesions will be discussed. This review could improve the understanding of pediatric IAVSs and their diagnosis and treatment.

Occlusion of a mural type vein of Galen malformation in a 10-month-old boy with three Woven EndoBridge (WEB 17) and two coils

We report the case of a 10-month-old boy with an enlarged head circumference and severe motor developmental delay. MRI showed a vein of Galen malformation (VGAM) with a heavily dilated median prosencephalic vein. Digital subtraction angiography confirmed a mural type VGAM with three feeding arteries arising from the posterior cerebral arteries. Due to the short length of the feeding arteries and the high flow, occlusion of the feeding vessels with detachable coils was not possible because of repeated coil dislocation into the dilated vein. Embolization of the three feeding vessels was then performed with a Woven EndoBridge single layer device (WEB SL17). In two arteries complete occlusion was accomplished with the WEB alone and in one artery additional deployment of two coils was necessary. Follow-up imaging at day 1 after treatment as well as 3 and 9 months after embolization showed persistent occlusion.

Unruptured brain arteriovenous malformations and hydrocephalus: Case series and review of the literature

OBJECTIVE

Hydrocephalus is an uncommon presentation of unruptured brain arteriovenous malformations (AVMs). The goal of this case series and literature review is to present possible pathological mechanisms, management strategies and outcomes in patients with hydrocephalus due to unruptured AVMs.

METHODS

Three consecutive patients with hydrocephalus caused by unruptured AVMs as well as all cases previously reported in the literature were retrospectively reviewed to determine clinical symptoms, AVM location, nidus size, venous drainage, mechanism of hydrocephalus, level/cause of obstruction, and degree of hydrocephalus. Management of hydrocephalus, AVM treatment, and follow-up length were evaluated.

RESULTS

Of 350 patients unruptured AVMs, 3 presented with hydrocephalus (0.8%). In the literature review we found an additional 22 patients for a total of 25 cases. Eighteen patients had mechanical obstruction by the draining vein or the AVM nidus, usually at the level of the aqueduct (52%). Impaired cerebrospinal fluid resorption secondary to venous congestion led to hydrocephalus in 7 patients. Ten patients were treated for both the AVM and hydrocephalus, 13 patients underwent treatment of either hydrocephalus, or the AVM alone. Treatment of hydrocephalus, with or without associated treatment of the brain AVM, resulted in improvement of symptoms in 92% of patients. No rupture of the AVM was reported at follow-up.

CONCLUSIONS

The most common cause of hydrocephalus in unruptured brain AVMs is mechanical obstruction by the draining vein if it is located in a strategic position. Treatment of hydrocephalus alone or with associated treatment of the AVM is safe and effective.

Imaging Characteristics of Dural Arteriovenous Fistulas Involving the Vein of Galen: A Comprehensive Review

Vein of Galen aneurysmal malformation (VGAM) is a rare angiopathy, which most commonly presents in infancy. Although very rare, it is associated with high morbidity and mortality rates. In order to minimize such morbid rates, a prompt diagnosis followed by a timely initiation of management is crucial. Multiple antenatal and postnatal imaging techniques for the diagnosis have been described and discussed in the literature. However, to our knowledge, a comprehensive review exploring such a list of imaging options for VGAM has never been established. We aim to review the diagnostic tools to aid in better understanding of the investigative modalities physicians may choose from when treating patients with a VGAM.

Superselective transvenous embolization with Onyx and n-BCA for vein of Galen aneurysmal malformations with restricted transarterial access: safety, efficacy, and technical aspects

PURPOSE AND METHODS

Superselective transvenous embolization (TVE) with liquid embolic agents is a new concept in treatment of vein of Galen aneurysmal malformations (VGAM). We performed ten sessions of TVE in VGAM patients with restricted transarterial access. In this paper, we assessed clinical and angiographic outcomes of the proposed treatment and discussed three different TVE techniques with regard to morphology of the shunt and outflow tract. Safety and avoidance-of-complication tips were also discussed.

RESULTS

Patient age ranged from 4 to 51 months. There were eight patients with choroidal VGAMs, seven of them were successfully treated with Onyx, and in one case, transvenous catheterization failed. In three cases, adjunctive coiling of draining vein was performed. In three cases, normal deep cerebral veins were connected to the outflow part of malformation; they were preserved during embolization in all cases. Six-month follow-up angiography demonstrated angiographic cure in six cases, and partial occlusion in one. There were two patients with mural VGAMs: both were treated with n-BCA. Partial occlusion was achieved in both cases. There was no procedure-related permanent morbidity or mortality. Oculomotor deficit due to quadrigeminal ischemia occurred in one case, and resolved completely after 3 weeks.

CONCLUSION

TVE with liquid embolic agents is a safe and effective salvage method for VGAMs with restricted transarterial access, previously considered as poor candidates for endovascular treatment.

Intracranial non-galenic pial arteriovenous fistula: A review of the literature

An intracranial non-galenic pial arteriovenous fistula (NGPAVF) is a direct connection between the intracranial artery and vein without a nidus. NGPAVFs are clinically rare, and the current understanding of NGPAVFs is limited. This study searched PubMed for the currently available literature, and a review of the relevant publications revealed that NGPAVFs require aggressive treatment, spontaneous occlusion is uncommon, and the prognosis following conservative treatment is poor. NGPAVFs can be divided into congenital and traumatic (including iatrogenic) types. Clinically, NGPAVFs are characterized by congestive heart failure, epilepsy, hemorrhage, mass effects, and nerve function deficits. For the imaging examination of NGPAVFs, digital subtraction angiography (DSA) is still the gold standard for diagnosis, although magnetic resonance DSA (MRDSA) and 4D computed tomography angiography (CTA) can also provide hemodynamic data in a non-invasive manner. Current treatments for NGPAVFs include surgical resection and endovascular embolization, both of which can yield clinical improvements. However, potential postoperative complications should be addressed, such as fatal bleeding due to rupture and deep vein thrombosis. Some studies recommend postoperative anticoagulation to reduce postoperative thrombotic complications.