Endovascular advances for brain arteriovenous malformations

Risk assessment for rupture of brain arteriovenous malformations using high-resolution black-blood magnetic resonance imaging: a single-center case series

OBJECTIVE

Chronic inflammation's role in the pathogenesis, development, and rupture of vascular malformations is undebated. Advanced magnetic resonance imaging techniques with vessel wall studies, specifically Black Blood (bbMRI), may offer insights into vascular wall instability and predict rupture. This case series aims to assess bbMRI as a predictive diagnostic tool for brain arteriovenous malformations (bAVMs) rupture, suggesting early treatment.

MATERIAL AND METHODS

A prospective study included demographic, clinical, and neuroimaging data from a consecutive series of patients with ruptured or unruptured bAVMs, regardless of age or gender, between October 2018 and March 2024. All patients underwent MRI brain resonance with Black Blood study. Those with impaired renal function were excluded. Statistical analyses tested sample homogeneity. Univariate and multivariate logistical regressions assessed bbMRI as a rupture predictor for bAVMs, with a p-value set at < 0.05.

RESULTS

Ninety patients were retrieved: 64 with unruptured and 26 with ruptured bAVMs. The mean age was 31.9 years, and 55 were female. Admission symptoms were headache, neurological deficits, and seizure in 49, 21, and 19 cases, respectively. bbMRI showed wall enhancement in 56 cases, with 19 in the ruptured and 37 unruptured groups. Univariate and multivariate analyses revealed a significant correlation between bbMRI wall enhancement and bAVM rupture (p:0.033; p:0.047).

CONCLUSION

bbMRI may be a useful and feasible diagnostic implement to determine vessel inflammation and the bAVMs prone to rupture. Additional studies are needed to confirm the positive bbMRI as a predictive factor for bAVMs rupture.

Angiographic Evolution of Brain Arteriovenous Malformation Angioarchitecture After Partial Endovascular Treatment

BACKGROUND AND OBJECTIVES

Endovascular embolization of brain arteriovenous malformations (AVMs) is sometimes intentionally partial, in the case of staged treatment for instance. Residual AVMs may be prone to angioarchitectural modification during follow-up. The objective of this work is to evaluate the nature and extent of these modifications.

METHODS

We performed a retrospective monocentric study on a cohort of adult patients treated by incomplete endovascular embolization for ruptured and unruptured AVMs with an available angiographic follow-up, without any intervening confounding event between the 2 angiographic examinations. AVM angioarchitectural modifications (arterial, nidal, and venous) were analyzed. Clinical and radiological data were tested in univariate analyses for association with the occurrence of AVM regression or progression.

RESULTS

Eighty-two partial embolization sessions in 57 patients were included in the study. A 40% (33/82) rate of modification was found on follow-up, with 23/82 (28%) controls showing at least one angioarchitectural regression feature and 15/82 (18.3%) showing at least one angioarchitectural progression item. Nidal growth was the most frequent modification occurring after 12/82 (14.6%) embolizations. The only factor associated with nidal volume growth was a longer time interval between embolization and follow-up (median [IQR]: 190 [250] days vs 89.5[133] days in the subgroup without nidal growth; P = .02). Specific modifications of arterial supply, nidal anatomy, and venous drainage were identified and documented.

CONCLUSION

Angioarchitectural modifications (both progression and regression) of brain AVMs are frequent findings after partial embolization. Nidal volume growth is associated with longer time intervals between embolization and follow-up.

Preoperative embolization of brain arteriovenous malformation and efficacy in intraoperative blood loss reduction: a quantitative study

BACKGROUND

Embolization of brain arteriovenous malformations (bAVMs) is often used as adjuvant therapy to microsurgical resection to reduce the high-risk features of bAVMs such as large size and high flow. However, the effect of preoperative embolization on surgical performance and patient outcome has shown mixed results. Heterogeneity in treatment goals, selection criteria, and unpredictable changes in bAVM hemodynamics after partial embolization may account for these uncertain findings. In this study we use an objective quantitative technique to assess the impact of preoperative embolization on intraoperative blood loss (IBL).

METHODS

Patients with bAVM treated with microsurgical resection only or in combination with preoperative embolization from 2012 to 2022 were retrospectively reviewed. Patients were included if quantitative magnetic resonance angiography was performed prior to any treatment. Correlation of baseline bAVM flow, volume, and IBL was evaluated between the two groups. Additionally, bAVM flow prior to and after embolization was compared.

RESULTS

Forty-three patients were included, 31 of whom required preoperative embolization (20 had more than one session). Mean bAVM initial flow (362.3 mL/min vs 89.6 mL/min, p=0.001) and volume (9.6 mL vs 2.8 mL, p=0.001) were significantly higher in the preoperative embolization group; flow decreased significantly after embolization (408.0 mL/min vs 139.5 mL/min, p<0.001). IBL was comparable between the two groups (258.6 mL vs 141.3 mL, p=0.17). Linear regression continued to show a significant difference in initial bAVM flow (p=0.03) but no significant difference in IBL (p=0.53).

CONCLUSION

Patients with larger bAVMs who underwent preoperative embolization had comparable IBL to those with smaller bAVMs undergoing only surgical treatment. Preoperative embolization of high-flow bAVMs facilitates surgical resection, reducing the risk of IBL.

Multiple Intracranial Aneurysms Associated With Brain Arteriovenous Malformation: A Case Report and Treatment Strategies

In the field of cerebrovascular neurosurgery, intracranial aneurysms (IAs) have been occasionally associated with brain arteriovenous malformations (BAVMs), indicating a more aggressive clinical course, and increased rates of hemorrhage and rehemorrhage. Treatment of flow-related IAs in BAVMs remains debatable, with considerations for preventive intervention versus concurrent BAVM treatment. Managing such situations might be challenging, especially in determining which of the IAs or BAVMs should be treated first, and which treatment strategy would be most appropriate for each situation. A precise identification of the rupture site is required, whether it is the AVM nidus or the IA, for choosing the best treatment plans. We present a case of a 29-year-old male patient diagnosed with several intracranial vascular conditions: a ruptured anterior communicating artery (ACoA) aneurysm and an unruptured ophthalmic artery aneurysm, associated with a frontal BAVM. Moreover, we discussed the possible scenarios regarding the association of these conditions, highlighting their manifestations and the most suitable therapeutic approach for each. Thus, our exploration of the challenges and considerations involved in treating these intricate neurovascular conditions underscores the need for a customized approach for each patient's situation.

Most Promising Approaches to Improve Brain AVM Management: ARISE I Consensus Recommendations

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.

Treatment of an Intracranial Fusiform Vertebral Aneurysm Using the MVP® Micro Vascular Plug System as an Adjunct to Pipeline(TM) Embolization: Technical Case Instruction

Fusiform and dolichoectatic aneurysms pose unique challenges in treatment, often requiring alternative approaches compared to saccular aneurysms. Microsurgical options like clipping or a bypass can be difficult, leading to the advancement of endovascular techniques. Flow-diverting stents and vessel sacrifice with detachable coils have shown efficacy in reconstruction. The MVP® Micro Vascular Plug System (Medtronic, Minneapolis, Minnesota, USA) offers a resheathable plug for vessel occlusion through electrolytic detachment. This case report illustrates the supplementary application of MVP® subsequent to flow diverter (FD) stenting, resulting in the effective endovascular management of a fusiform aneurysm affecting both vertebral arteries (VA), following unsuccessful coil vessel sacrifice treatment. A 61-year-old female presented with an unruptured fusiform aneurysm in the bilateral vertebral arteries (VAs). Treatment included a flow diverter in the right VA and vessel sacrifice in the left VA using Onyx-18 and coils. Despite initial success, left V4 segment recanalization occurred. Endovascular treatment, deploying two devices and additional coils using the MVP®, halted the flow. Follow-up showed left VA occlusion and reconstruction of the treated right VA, with the patient being discharged without deficits. This case demonstrates a unique approach using MVP® alongside a flow diverter (a PipelineTM Embolization Device (PED), Medtronic) for the treatment of a V4 segment fusiform aneurysm. This innovative technique is an alternative when conventional coil embolization for vessel sacrifice fails. The MVP®'s ease of use and precise delivery render it a feasible and efficacious alternative for treating complex aneurysms.

Case Study of a Complex Neurovascular Disorder: Choroidal Arteriovenous Malformation

This study conducts an in-depth analysis of the management of a complex arteriovenous malformation (AVM) in a 44-year-old individual, who initially manifested with acute left hemiparesis and progressively declined into a comatose state. Diagnostic neuroimaging identified a substantial right fronto-temporal intraparenchymal hematoma via a CT scan. Cerebral angiography further elucidated a choroidal AVM originating from the anterior choroidal artery, accompanied by intranidal aneurysms. The elected treatment strategy was the surgical excision of the AVM. The procedure achieved complete removal of the intracranial AVM, situated in a neurologically sensitive region, leading to notable neurological recovery. This study thoroughly explores and critically evaluates a wide spectrum of treatment approaches for intracranial arteriovenous malformations, including novel endovascular therapies. Despite extensive discourse on AVM in contemporary literature, this report is among the few documenting the treatment of a choroidal AVM via a microsurgical technique, and highlights various therapeutic options.

Spontaneous thrombosis of deep brain arteriovenous malformation in a patient with intraventricular and subarachnoid hemorrhage

The most common manifestation of brain arteriovenous malformations (BAVM) is intracranial hemorrhage. The incidence of ruptured BAVM is 3.5 per 100,000 people per year. The mortality rate of ruptured BAVM within 1 month after diagnosis was 12.7%. Spontaneous thrombosis occurs in less than 1.5% of ruptured BAVMs. This phenomenon was still elusive. Up until now, the gold standard of imaging examination has been cerebral digital subtraction angiography (DSA), whose sensitivity and specificity reach 100%. We reported the spontaneous thrombosis of a ruptured deep BAVM. An 18-year-old woman presented with severe headache and vomiting. The patient also complained of seizures. There was no body weakness, skewed face, or slurred speech. Cerebral computed tomography (CT) showed extensive hemorrhage in the ventricular system and subarachnoid space. Cerebral DSA showed a left subcortical BAVM and was found to have spontaneous thrombosis 3 weeks later when the patient was about to be embolized. Spontaneous thrombosis of ruptured BAVM may occur after intracranial hemorrhage. In this patient, spontaneous thrombosis occurred within 3 weeks.

Safety and efficacy of dual lumen balloon catheters for the Treatment of cerebral vascular malformations: A systematic review, pooled analysis, and meta-analysis

BACKGROUND

There is little evidence in scientific literature assessing the safety and efficacy of dual-lumen balloon catheters (DLBCs) and their performance compared to single-lumen catheters (SLCs).

METHODS

In this PROSPERO-registered, PRISMA-compliant systematic review, we identified all MEDLINE and EMBASE single-arm (DLBCs) and double-arm (DLBCs vs SLCs) cohorts where DLBCs were used for the treatment of cerebral arteriovenous malformations (AVMs) or dural arteriovenous fistulas (dAVFs). Immediate angiographic outcome, vascular complications, technical failures, reflux episodes and entrapment were the primary outcomes. A meta-analysis of the double-arm studies summarized the primary outcomes of total procedural time and immediate angiographic outcome.

RESULTS

The authors identified 18 studies encompassing 209 treated lesions with reported outcomes. Complete occlusion was achieved in 108/132 treated dAVFs (81.8%, 95% CI: [74-87.8%]) and in 45/77 treated AVMs (58.4%, [46.7-69.4%]). The proportion of completely occluded dAVFs was statistically significantly higher than that of AVMs, p < .001. There were eight reported vascular complications (3.8%, [1.8-7.7%]), five technical failures (2.4%, [0.9-5.8%]), 14 reflux events (6.7%, [3.9-11.2%]), two entrapment events (1%, [0.2-3.8%]) and 0 deaths (mortality rate 0%, [0-2.3%]). In a meta-analysis for the treatment of dAVFs, the total procedural time was significantly less for DLBCs compared to SLCs (64.9 vs 125.7 min, p < .0001). The odds of complete immediate occlusion were significantly higher with DLBCs compared to SLCs (odds ratio (OR) 4.6, [1.5-14.3], p = .008).

CONCLUSION

Dual-lumen balloon catheters are safe and effective for the embolization of cerebral AVMs and dAVFs and can achieve faster and potentially superior results compared to SLCs.

REGISTRATION-URL

https://www.crd.york.ac.uk/prospero/ Unique Identifier: CRD42021269096.

Application of the pressure cooker technique for transarterial embolization of brain arteriovenous malformations: Factors affecting obliteration and outcomes

Objective

The typical pressure cooker technique (PCT) and several modifications with similar mechanisms have been introduced to enhance the embolization of brain arteriovenous malformations (bAVMs). This study aimed to assess the effectiveness of transarterial embolization of bAVMs with the PCT.

Method

From January 2019 to December 2021, 125 consecutive patients with bAVM managed by transarterial embolization in the prospective database on cerebral vascular diseases of a single center were retrospectively reviewed. Patient data and lesion characteristics were collected. According to the treatment strategy, the patients were assigned to the PCT group (46 patients) and conventional embolization technique (CET) group (79 patients).

Results

Baseline patient features were comparable between the two groups. After the first procedure, complete obliteration immediately was observed in 61 and 42% of patients in the PCT and CET groups, respectively. The rate was markedly elevated in the PCT group (p = 0.04). In subgroup analysis, the rate of immediate complete obliteration was starkly increased in PCT group patients with Spetzler-Martin grade I/II bAVM (86 and 53% in the PCT and CET groups, respectively; p = 0.0036). The overall complication rates were similar in the two groups (13 and 10% in the PCT and CET groups, respectively; p = 0.77). In multivariable analysis, nidus size >3 cm (OR = 8.826, 95% CI: 1.250-62.312; p = 0.03) and deep location (OR = 8.576, 95% CI: 1.480-49.690; p = 0.02) were significant factors affecting complete obliteration in the PCT group.

Conclusion

The PCT may yield a higher rate of immediate complete obliteration with transarterial embolization of bAVMs, without increasing the rate of procedure-related complications.

FLAIR hyperintense vessels on MRI post brain arteriovenous malformation embolization: A novel finding associated with post-procedure intraparenchymal hemorrhage

INTRODUCTION

Brain arteriovenous malformations (BAVMs) are frequently managed by endovascular embolization with a growing number of centers embolizing with intent to cure. Hemorrhage post-embolization is a severe and poorly understood complication. We present a novel imaging finding associated with post-embolization hemorrhage that has significantly impacted the management of patients at our institution.

METHODS

A retrospective review of all patients undergoing embolization of BAVM at a single center was performed. Post-embolization magnetic resonance imaging (MRI) was reviewed for the presence of T2 fluid-attenuated inversion recovery (FLAIR) hyperintense vessels (FHVs). Bivariate analysis was performed to determine associations between patient characteristics and risk of hemorrhage.

RESULTS

A total of 50 patients underwent 75 embolization procedures. Forty-six post-embolization MRIs were available for review. There were four hemorrhages and 100% of those presented with FHV. In contrast, only 11.9% of embolization procedures without post-procedural hemorrhage had FHVs on MRI. In total, 18.7% of embolizations led to some morbidity or mortality, with only 6.7% leading to permanent morbidity or mortality. In bivariate analysis, only the presence of FHVs was correlated with the risk of hemorrhage (p < 0.05).

CONCLUSIONS

This is the first series to describe the finding of hyperintense blood vessels on FLAIR imaging after embolization of BAVMs and correlate it with hemorrhage post embolization. This finding can help guide practitioners and potentially identify patients at risk of delayed hemorrhage post embolization.

Brain AVMs-Related microRNAs: Machine Learning Algorithm for Expression Profiles of Target Genes

INTRODUCTION

microRNAs (miRNAs) are a class of non-coding RNAs playing a myriad of important roles in regulating gene expression. Of note, recent work demonstrated a critical role of miRNAs in the genesis and progression of brain arteriovenous malformations (bAVMs). Accordingly, here we examine miRNA signatures related to bAVMs and associated gene expression. In so doing we expound on the potential prognostic, diagnostic, and therapeutic significance of miRNAs in the clinical management of bAVMs.

METHODS

A PRISMA-based literature review was performed using PubMed/Medline database with the following search terms: "brain arteriovenous malformations", "cerebral arteriovenous malformations", "microRNA", and "miRNA". All preclinical and clinical studies written in English, regardless of date, were selected. For our bioinformatic analyses, miRWalk and miRTarBase machine learning algorithms were employed; the Kyoto Encyclopedia of Genes and Genomes (KEGG) database was quired for associated pathways/functions.

RESULTS

four studies were ultimately included in the final analyses. Sequencing data consistently revealed the decreased expression of miR-18a in bAVM-endothelial cells, resulting in increased levels of vascular endodermal growth factor (VEGF), Id-1, matrix metalloproteinase, and growth signals. Our analyses also suggest that the downregulation of miR-137 and miR-195* within vascular smooth muscle cells (VSMCs) may foster the activation of inflammation, aberrant angiogenesis, and phenotypic switching. In the peripheral blood, the overexpression of miR-7-5p, miR-629-5p, miR-199a-5p, miR-200b-3p, and let-7b-5p may contribute to endothelial proliferation and nidus development. The machine learning algorithms employed confirmed associations between miRNA-related target networks, vascular rearrangement, and bAVM progression.

CONCLUSION

miRNAs expression appears to be critical in managing bAVMs' post-transcriptional signals. Targets of microRNAs regulate canonical vascular proliferation and reshaping. Although additional scientific evidence is needed, the identification of bAVM miRNA signatures may facilitate the development of novel prognostic/diagnostic tools and molecular therapies for bAVMs.

Transvenous embolization of hemorrhagic brain arteriovenous malformations: Case reports and literature review

Introduction

Transvenous embolization (TVE) has been proven to be safe and feasible as an alternative management of brain arteriovenous malformations (AVMs). We presented four patients with a hemorrhagic brain AVM who underwent TVE and reviewed the relevant literature.

Methods

Four patients underwent TVE of a hemorrhagic brain AVM in our center between July 2019 and July 2020. We retrospectively collected and analyzed the clinical and imaging data of these patients and those reported in previously published studies.

Results

Four patients with a hemorrhagic brain AVM were included. Nidus sizes ranged from 0.79 to 2.56 cm. Spetzler-Martin grade ranged from grade II to grade III. The AVM nidus was located in a deep brain region in three patients. One patient underwent TVE alone and three underwent combined transarterial and transvenous approaches. Digital subtraction angiography (DSA) demonstrated complete obliteration of the vascular malformation after embolization in all four patients. Three patients were independent [modified Rankin Scale (mRS) score ≤ 2] at discharge. All four patients were independent at the last follow-up. AVM obliteration was confirmed in all four patients at the last angiographic follow-up.

Conclusion

Transvenous embolization can be used as an alternative treatment for contemporary management of brain AVMs, appropriate patient selection is essential to achieve a good clinical outcome.

A phantom-based study and clinical implementation of brainlab's treatment planning system for radiosurgical treatments of arteriovenous malformations

PURPOSE

Development of a simple, phantom-based methodology allowing for pilot applications for the Elements TPS cranio-vascular module and clinical implementation prior to AVM treatments.

METHODS

A customized phantom was developed to be visible in MRI and CT images. High resolution digital subtraction angiograms (DSAs) and CT images of the phantom were acquired and imported into the Brainlab Elements treatment planning system. A clinical treatment plan with 5 arcs was generated in cranial vascular planning module and delivered to the phantom using a Varian TrueBeam STx Linac equipped with HD-MLCs and Brainlab ExacTrac imaging system for non-coplanar setup verification. The delivered dose was verified using a calibrated ionization chamber placed in the phantom. Upon verification of the TPS workflow, three patients with AVM who have been treated to date at our center using the Brainlab's cranial vascular module for AVM are presented here for retrospective review.

RESULTS

The difference between the planed and measured dose by the ionization chamber was found to be less than 1%. Following a successful dose verification study, a clinical workflow was created. Currently, three AVM patients have been treated successfully. Clinical aspects of imaging and treatment planning consideration are presented in retrospective setting.

CONCLUSIONS

Dose verification of the Brainlab Elements cranial vascular planning module for intracranial SRS treatments of AVM on Varian TrueBeam was successfully implemented using a custom-made phantom with <1% discrepancy. The Brainlab Elements' cranial vascular module was successfully implemented in clinical workflow to treat patients with AVM. This manuscript provides a guideline for clinical implementation of frameless Linac-based AVM treatment using the Brainlab Elements TPS.

Stereotactic Radio Surgery, Embolization and Conservative Management for Cerebral Arteriovenous Malformation: A New Zealand Experience of Long-Term Outcomes

OBJECTIVE

Cerebral arteriovenous malformations (AVMs) can be treated by microsurgery, stereotactic radiosurgery (SRS) as a stand-alone procedure, or combining embolization and conservative management. This single-center, retrospective review explored the outcomes of patients treated with SRS alone, embolization before SRS (ESRS), or conservative management for cerebral AVMs.

METHODS

Demographic details, Spetzler-Martin grade, SRS dose, obliteration, time to obliteration, imaging modality, rebleed, disease-specific mortality, and post-SRS complications were collected. Chi-square tests of independence and 1-way analysis of variance/Kruskal-Wallis tests were performed.

RESULTS

Two-hundred and thirty-nine patients were treated with SRS alone, 37 were treated with ESRS, and 83 were conservatively managed. Obliteration rates were 78% (SRS alone) and 70% (ESRS). Rebleed rates were comparable among SRS alone (4%), ESRS (0%), and conservative management (8%). Disease-specific mortality rates were significantly lower for SRS alone (1%) and ESRS (0%) compared with conservative management (6%, X² [2, n = 358] = 7.50, P = 0.024). Post-SRS complications occurred with SRS alone only and included radiation necrosis (n = 5), cavernous malformations (n = 2), and stroke (n = 1). Obliteration, rebleed, and disease-specific mortality rates were comparable among pediatric (<18 years), nonelderly (18-59 years), and elderly (≥60 years) age groups.

CONCLUSIONS

Findings suggest that SRS and ESRS are safe and effective treatments for cerebral AVM (when quantified by obliteration, rebleed, and disease-specific mortality rates). With multinational, prospective, randomized controlled trials with long follow-up periods, the effectiveness and safety of SRS and ESRS compared with conservative management for AVM will be further clarified.

Microsurgical Treatment of Deep and Eloquent AVMs

Over the past 30 years, the treatment of deep and eloquent arteriovenous malformations (AVMs) has moved away from microneurosurgical resection and towards medical management and the so-called minimally invasive techniques, such as endovascular embolization and radiosurgery. The Spetzler-Martin grading system (and subsequent modifications) has done much to aid in risk stratification for surgical intervention; however, the system does not predict the risk of hemorrhage nor risk from other interventions. In more recent years, the ARUBA trial has suggested that unruptured AVMs should be medically managed. In our experience, although these eloquent regions of the brain should be discussed with patients in assessing the risks and benefits of intervention, we believe each AVM should be assessed based on the characteristics of the patient and the angio-architecture of the AVM, in particular venous hypertension, which may guide us to treat even high-grade AVMs when we believe we can (and need to) to benefit the patient. Advances in imaging and intraoperative adjuncts have helped us in decision making, preoperative planning, and ensuring good outcomes for our patients. Here, we present several cases to illustrate our primary points that treating low-grade AVMs can be more difficult than treating high-grade ones, mismanagement of deep and eloquent AVMs at the behest of dogma can harm patients, and the treatment of any AVM should be tailored to the individual patient and that patient's lesion.

Single institution early clinical experience with the Scepter Mini balloon catheter

BACKGROUND

The use of liquid embolic agents in the endovascular treatment of dural arteriovenous (dAVFs) fistulas and brain arteriovenous malformations (AVMs) has become common practice. The use of dual lumen balloon microcatheters has greatly improved the efficacy of liquid embolization. The purpose of this series is to discuss our early experience with the Scepter Mini dual lumen balloon microcatheter.

METHODS

A retrospective chart review was performed of all patients who underwent embolization with the Scepter Mini dual lumen balloon at a single institution. Technical details and procedural complications were recorded for each case.

RESULTS

In total, 10 Scepter Mini dual lumen balloon microcatheters were used in nine patients. All patients except two were treated for AVMs. Technical success was achieved in all but one case where one balloon had to be discarded due to precipitation of the tantalum powder. Average vessel diameter where the balloon was inflated was 1.1 mm (0.8-2.4 mm). It provided flow arrest in 100% of cases with no cases of reflux of embolic material. Balloon "jump back" was found to occur in 44.4% (4/9) of cases. Seven out of nine cases used Onyx, and two cases used n-butyl cyanoacrylate.

CONCLUSIONS

The Scepter Mini is a new dual lumen balloon ideal for distal access and can be used for embolization with liquid embolic agents with a high degree of technical success. Its great benefit is the immediate and safe flow arrest of distal vasculature upon balloon inflation. One important consideration for effective embolization is early identification of balloon jump back.

The use of dual-lumen balloon for embolization of peripheral arteriovenous malformations

PURPOSE

We aimed to evaluate the safety and feasibility of the embolization of peripheral arteriovenous malformation (AVM) with non-adhesive liquid agents (NALA) injected by dual-lumen balloons (DLB).

METHODS

We conducted a multicenter retrospective study between January 2017 and June 2019, including patients with peripheral AVM embolized with NALA by DLB. Fourteen patients were included. The AVM classification, technical and clinical success were evaluated, as were nidus size, liquid agent used, volume and time of injection in DLB, complications, follow-up and need of surgical intervention.

RESULTS

The mean age of the patients was 37±22.5 years (range, 6-82 years). The mean nidus size was 5.2±2.4 cm (range, 3.0-12.0 cm). By Schobinger classification, 11 AVMs were classified in stage 3 and 3 AVMs were classified in stage 2. By Cho's classification, 2 AVMs were in stage II, 4 AVMs were in stage I, 4 AVMs were in stage IIIa and 4 AVMs were in stage IIIb. Onyx was used in 11 patients (78.6%), while Squid, PHIL, and both Onyx and Squid were used in one patient each (7.1%). Seven patients (50%) required one session of embolization, 4 patients (28.6%) required two, 2 patients (14.3%) required three and 1 patient (7.1%) required four sessions. Complete nidus exclusion was achieved in 11 patients (78.6%), optimal clinical response in 12 patients (85.7%). Four patients (28.6%) exhibited minor complications, all controlled. No major complications were seen. Four patients underwent surgical intervention (28.6%).

CONCLUSION

The embolization of peripheral AVM with NALA in DLB appears to be safe and feasible, achieving high rates of technical and clinical success.

Early Outcomes and Complications of Endovascular Treatment of Cerebral Arteriovenous Malformations in Pediatric Patients

INTRODUCTION

Arteriovenous malformations (AVMs) are the commonest cause of hemorrhagic stroke in children. Endovascular embolization is a feasible treatment modality, but cure rates are heterogenous from one series to another. We aimed to describe the immediate obliteration rates and periprocedural complications of embolization of pediatric AVMs.

METHODS

Between 2011 and 2019, participants below 18 years of age with AVMs treated by the same neurosurgeon at a single center were included. The clinical features, immediate angiographic results, and periprocedural complications were retrospectively collected from the clinical records.

RESULTS

Thirty-four embolization sessions were performed on 20 children (12 females with a mean age of 13). Intracranial hemorrhage was the most common presentation (75%), and the majority were frontal (30%) and basal ganglia (30%) lesions. An immediate complete angiographic obliteration was achieved in 9 patients (45%) with low-grade lesions (Spetzler-Martin grade I and II). NBCA was the most common embolic agent used (52.9%). Complications were reported in 3 (8.8%) out of 34 sessions. Two of them were intraoperative perforations with clinical consequences. A slight cortical hemorrhage during the procedure was observed in 1 patient without clinical repercussions.

DISCUSSION

This single-surgeon single-center experience suggests that endovascular treatment is a safe and efficient treatment for pediatric AVMs. Pediatric prognostic scores for a suitable selection of candidates are needed. Further studies are required to validate these results.

Flow driven robotic navigation of microengineered endovascular probes

Minimally invasive medical procedures, such as endovascular catheterization, have considerably reduced procedure time and associated complications. However, many regions inside the body, such as in the brain vasculature, still remain inaccessible due to the lack of appropriate guidance technologies. Here, experimentally and through numerical simulations, we show that tethered ultra-flexible endovascular microscopic probes can be transported through tortuous vascular networks with minimal external intervention by harnessing hydrokinetic energy. Dynamic steering at bifurcations is performed by deformation of the probe head using magnetic actuation. We developed an endovascular microrobotic toolkit with a cross-sectional area that is orders of magnitude smaller than the smallest catheter currently available. Our technology has the potential to improve state-of-the-art practices as it enhances the reachability, reduces the risk of iatrogenic damage, significantly increases the speed of robot-assisted interventions, and enables the deployment of multiple leads simultaneously through a standard needle injection and saline perfusion.

The navigation of catheters through blood vessels requires flexible guiding wires that are pushable and tractable at the same time. Pancaldi et al. rely on hydrodynamic forces and magnetic torque in order to access even rather small capillaries with an ultraflexible magnetomechanical probe.

Association between draining vein diameters and intracranial arteriovenous malformation hemorrhage: a multicentric retrospective study

PURPOSE

Intracranial arteriovenous malformations (AVMs) cause hemorrhage, and the role of draining vein diameters in rupture risk is controversial. The aims of the present study were to investigate the variables related with intracranial AVM rupture and to examine the association of draining vein diameters and AVM hemorrhage.

METHODS

Two hundred three patients were included in this study, of which 117 (57%) had unruptured AVMs, and 86 (43%) had ruptured AVMs.

RESULTS

In an adjusted (multivariate) analysis, the variables significantly associated with AVM hemorrhagic presentation were age (OR per year increase 0.97, 95%CI 0.95-0.99, p = 0.007), a deep nidus compared with superficial nidus (OR 3.21, 95%CI 1.13-9.06, p = 0.028), the nidus diameter (OR per each mm increase 0.95, 95%CI 0.92-0.97, p < 0.001), a single draining vein compared with multiple draining veins (OR 2.14, 95%CI 1.02-4.50, p = 0.044), the draining vein diameter (OR per mm increase 1.52, 95%CI 1.26-1.83, p < 0.001), and a draining vein diameter ≥ 5 mm compared with < 5 mm (OR 5.80, 95%CI 2.70-12.47, p < 0.001).

CONCLUSION

In this study, after adjusted analysis, the variables associated with intracranial AVM hemorrhagic presentation were a young age, a small nidus diameter, a deeply located nidus, a single draining vein, and large draining vein diameters. A draining vein diameter cutoff ≥ 5 mm was positively associated with the risk of AVM rupture. A large and prospective study is now necessary to confirm if draining vein diameter is a risk factor for AVM hemorrhage.

Comparison of predictive grading systems for procedural risk in endovascular treatment of brain arteriovenous malformations: analysis of 104 consecutive patients

OBJECTIVE

Several grading systems for procedural risk in the endovascular treatment of brain arteriovenous malformations (AVMs) have been proposed, including the Buffalo, Puerto Rico, and AVM embocure scoring systems. The authors sought to validate these systems in an independent patient cohort and compare each system to the established Spetzler-Martin (SM) scale.

METHODS

One hundred four consecutive patients underwent adjunctive endovascular embolization of brain AVMs between 2002 and 2016 with the goal of reducing the surgical or hemorrhagic risk before definitive radiosurgical treatment. Baseline clinical and AVM characteristics, complications, and degree of AVM nidus reduction were obtained retrospectively. Univariate and multivariate comparisons and receiver operating characteristic (ROC) curve analyses were performed.

RESULTS

Ten major (9.6%) and 16 minor (15.4%) complications were encountered in 24 patients (23.1%). An arterial pedicle size < 1 mm (p = 0.001) and a greater number of pedicles (p = 0.039) were predictors of complication occurrence. Only the Buffalo score predicted the complication rate on univariate (p = 0.039) and multivariate (p = 0.001) analyses. ROC curve analysis revealed a greater area under the curve (AUC) of the Buffalo score (0.703) compared to the Puerto Rico score (p = 0.028), AVM embocure score (AVMES; p = 0.010), and SM grade (SMG; p = 0.030). The Buffalo score, Puerto Rico score, and AVMES but not the SMG predicted > 85% nidus reduction. The AUCs for the different scoring systems were not significantly different.

CONCLUSIONS

The major complication rate of 9.6% is within the range of rates reported in the literature and emphasizes that brain AVM embolization is not a low-risk procedure. The Buffalo score but not the Puerto Rico score, AVMES, or SMG predicted the endovascular procedural risk. All three endovascular scores but not the SMG predicted a > 85% nidus reduction rate in this cohort embolized as part of a multimodal AVM treatment.

Five Cases of High-grade Arteriovenous Malformation Treated by Presurgical Embolization through the Anterior Choroidal Artery

Objective

In cases of cerebral arteriovenous malformation (AVM) in which perforators are involved as feeder, hemostasis is difficult during surgical removal and postoperative hemorrhage may develop. If possible, presurgical embolization should be performed. However, when the anterior choroidal artery (AChA) is the feeder, the risk of embolization is particularly high, and there are few reports describing this situation. Authors report the treatment results of five cases of AVM in which a single operator performed presurgical embolization through the AChA and describe the technique with a review of the literature.

Case Presentations

Of the five total cases (three men and two women; average age was 43.4 years [28-68 years]), one case presented with hemorrhage, two with epilepsy, the other ones with headache and trigeminal neuralgia, respectively. The lesions were located in the frontal lobe in one case and in the temporal lobe in four cases. On the Spetzler-Martin (SM) grading scale, four cases were grade III and one was grade IV. The eloquent area was involved within the nidus in four cases. Multimodal treatment was planned because all cases were high-grade AVM. Authors thought that performing presurgical embolization through the AChA would reduce the overall risk of treatment and performed the presurgical embolization. The embolization was possible in all cases, and the AVM was not angiographycally visible through the AChA in three cases. The blood flow through the AChA was reduced in two cases. All cases were awake immediately after embolization and no case had neurological symptom after embolization. CT or MRI after embolization revealed asymptomatic infarction in two cases. The AVM was removed safely without difficulty including hemostasis.

Conclusion

In this series, there were no morbidity and embolization was performed relatively safely. Embolization through the AChA was suggested to be an effective treatment, but careful consideration is required in each individual case.

Same day embolisation followed by microsurgical resection of brain arteriovenous malformations: a single centre early experience

INTRODUCTION

The purpose of this paper is to report our experience of treating cerebral arteriovenous malformations (AVM) in adults with pre-operative embolisation and microsurgical resection on the same day during a single anaesthetic at a single centre between April 2016 and December 2018. We included both elective AVM and AVM that had bled acutely.

METHODS

We retrospectively analysed data from patients with cerebral AVMs who underwent embolisation followed by microsurgical resection on the same day at a single neurosurgical centre.

PRIMARY ENDPOINTS INCLUDED

Total procedure time (embolisation and microsurgical resection), procedure finish time, intra-operative blood loss, degree of nidus obliteration on postoperative angiography, intensive care unit (ICU) stay, total stay at the neurosurgical centre and modified Rankin Score (pre- and post-procedure).

RESULTS

•Nineteen patients underwent same-day pre-operative embolisation and microsurgical resection over the 32-month period. The average patient age was 40 years (range 19-66 years). One patient had undergone a prior attempt at embolisation and one patient previously had sterotactic radiosurgery (STRS). •Thirteen of the AVM were in the dominant hemisphere and six in the non-dominant hemisphere. Sixteen AVM were located supratentorially and three were in the posterior fossa. Spetzler-Martin grades included 4 grade 1, 10 grade 2, 4 grade 3 and 1 grade 4. •The average blood loss intra-operatively was 289 mls. •The average list finish time was 19:56 (range 15:10-00:00). •Seventeen patients had 100% nidus obliteration on post-operative digital subtraction angiography, one patient had a small remnant and was referred to STRS and one patient died in the ICU post operatively.

CONCLUSION

Overall, the authors believe same-day embolisation and microsurgical resection represents a safe treatment strategy. The technique minimises hemorrhagic complications from delayed venous occlusion and avoids multiple anaesthetics and hospital admissions.

Complications of Endovascular Treatments for Brain Arteriovenous Malformations: A Nationwide Surveillance

BACKGROUND AND PURPOSE

Embolization is widely performed to treat brain arteriovenous malformations, but little has been reported on factors contributing to complications. We retrospectively reviewed a nationwide surveillance to identify risk factors contributing to complications and short-term clinical outcomes in the endovascular treatment of brain arteriovenous malformations.

MATERIALS AND METHODS

Data for endovascular treatment of brain arteriovenous malformations were extracted from the Japanese nationwide surveillance. Patient characteristics, brain arteriovenous malformation features, procedures, angiographic results, complications, and clinical outcomes at 30 days postprocedure were analyzed.

RESULTS

A total of 1042 endovascular procedures (788 patients; mean, 1.43 ± 0.85 procedures per patient) performed in 111 institutions from 2010 to 2014 were reviewed. Liquid materials were used in 976 procedures (93.7%): to perform presurgical embolization in 638 procedures (61.2%), preradiosurgical embolization in 160 (15.4%), and as sole endovascular treatment in 231 (22.2%). Complete or near-complete obliteration of brain arteriovenous malformations was obtained in 386 procedures (37.0%). Procedure-related complications occurred in 136 procedures (13.1%), including hemorrhagic complications in 59 (5.7%) and ischemic complications in 57 (5.5%). Univariate analysis identified deep venous drainage, associated aneurysms, infratentorial location, and preradiosurgical embolization as statistically significant risk factors for complications. Multivariate analysis showed that embolization of brain arteriovenous malformations in the infratentorial location was significantly associated with complications. Patients with complications due to endovascular procedures had worse clinical outcomes 30 days after the procedures than those without complications.

CONCLUSIONS

Complications arising after endovascular treatment of brain arteriovenous malformations are not negligible even though they may play a role in adjunctive therapy, especially in the management of infratentorial brain arteriovenous malformations.

Intermixed Dimethyl-Sulfoxide-Based Nonadhesive Liquid Embolic Agents Delivered Serially via the Same Microcatheter for Cerebral AVM Treatment

BACKGROUND AND PURPOSE

Conventional nonadhesive liquid embolic agents currently are the criterion standard for endovascular embolization of cerebral AVMs. However, inadequate distal penetration into the nidus and unstable proximal plug formation are the major limitations of this approach and of the currently available embolic materials. The aim of this study was to evaluate the hypothetic efficacy of combining liquid embolic agents with different properties and viscosities for use in endovascular embolization of cerebral AVMs.

MATERIALS AND METHODS

From March 2018 to March 2019, sixteen patients with cerebral AVMs (12 women, 4 men; age range, 33-61 years) underwent endovascular embolization with combined liquid embolic agents delivered serially via a single microcatheter. The procedure consists of initial embolization with PHIL 30%, followed by Menox 18 through the same microcatheter. According to the Spetzler-Martin scale, 11 (68.75%) AVMs were grades I-II, 4 (25%) were grade III, and 1 (6.25%) was grade IV. Angiographic, technical, and clinical outcomes were analyzed independently.

RESULTS

Combined PHIL and Menox embolization through the same microcatheter via 21 pedicles was performed in these 16 patients. Once the length of the reflux reached approximately 2 cm, PHIL 30% was switched to Menox 18. Antegrade flow and distal penetration of the serially applied liquid embolic agents were observed in all 16 cases. The ability to completely control the flow of the materials and avoid any dangerous proximal reflux was noted in all performed embolizations. The estimated average size reduction of the treated AVMs was 85%, ranging from 50% to 100%. Complete embolization was achieved in 10/16 or 62.5% of the cases. There was no procedure-related complication during or after the embolization. No mortality or postprocedural clinical worsening was seen. Clinical success and complete obliteration were confirmed with at least 1 follow-up angiography in 10/16 patients.

CONCLUSIONS

Serial delivery of nonadhesive liquid embolic agents via the same microcatheter was safe and effective in our study and may be a potential technique for routine AVM treatment. However, further investigations are required to validate the safety and the efficacy of the method.

Brain arteriovenous malformation with transdural blood supply: Current status

Arterial blood supply to a brain arteriovenous malformation (BAVM) is mainly derived from the internal carotid artery (ICA) and vertebral basilar artery (VBA) system. However, in certain cases, arteries supplying the meninges may also contribute to the blood supply of the BAVM, resulting in the formation of a BAVM with transdural blood supply (TBS). To review the current status of BAVM with TBS, a literature search was performed in the PubMed database. Articles were screened for relevance and suitability of data. According to recent studies, the mechanisms by which TBS to a BAVM forms are mainly classified into the congenital and acquired type. BAVM with TBS is common in elderly patients and is characterized by intracranial hemorrhage, epilepsy, chronic headache and increased intracranial pressure. Digital subtraction angiography is the gold standard for diagnosing BAVM with TBS. Superselective angiography is also important. Treatments for BAVM with TBS include surgical resection, endovascular treatment (EVT), stereotactic radiosurgery and combined treatment. Surgical resection is difficult to perform. EVT has become the major therapy for treating BAVM with TBS due to its low procedural invasiveness. Combination of surgical resection and EVT may be a good option. In addition, stereotactic radiosurgery is frequently used as a complementary treatment to surgical and endovascular interventions. The prognosis of BAVM with TBS is not favorable, as the defect involves a complex arterial supply system.

The Role of Matrix Metalloproteinase-3 in the Doxycycline Attenuation of Intracranial Venous Hypertension-Induced Angiogenesis

BACKGROUND

The molecular mechanism of brain arteriovenous malformation (BAVM) is largely unknown. Intracranial venous hypertension (VH) may enhance focal angiogenesis and promote BAVM development and progression. A rat VH model effectively simulates the hemodynamic microenvironment of this disease.

OBJECTIVE

To explore the effect of doxycycline in VH-related angiogenesis, as well as the role of matrix metalloproteinase-3 (MMP-3) and other molecular factors.

METHODS

A rat VH model was generated by common carotid artery and distal external jugular vein anastomosis. Microvessel density (MVD) in the perisinus area and expression of MMP-3/2/9, VEGF, TIMP-1, TGF-β, and HIF-1α were examined, with and without daily doxycycline treatment for 4 wk. The effects of doxycycline were verified in Vitro using human brain microvascular endothelial cells (HBMECs). MMP-3 overexpression or knockdown in HBMECs was used to confirm the role of MMP-3 in cell functions.

RESULTS

MVD in the perisinus cortex was greatly increased after VH. Doxycycline decreased MVD, suppressed MMP-3 overexpression, and reduced VEGF, TGF-β, and TIMP-1 levels compared with the controls (P < .05). In Vitro, doxycycline decreased HBMEC migration, tube formation, and the mRNA, protein, and enzymatic activity levels of MMP-3. MMP-3 overexpression in HBMECs promoted migration, while knockdown of MMP-3 significantly attenuated proliferation, migration, and tube formation (P < .05).

CONCLUSION

Our findings indicate that MMP-3 plays an important role in VH-related angiogenesis and the promotion of vascular remodeling. Suppression of MMP-3 overexpression by doxycycline may provide a potential strategy for inhibiting BAVM development.

Initial experience with the new ethylene vinyl alcohol copolymer based liquid embolic agent Menox in the endovascular treatment of cerebral arteriovenous malformations

Background and Purpose

Liquid embolic agents (LEAs) are the determinant tool for successful embolization of cranial arteriovenous shunts. There are few currently available LEAs. The aim of the study was to summarize our initial experience with a recently introduced non-adhesive ethylene vinyl alcohol (EVOH) copolymer based LEA (Menox 18) in the endovascular treatment of cerebral arteriovenous malformations.

Methods

From April 2018 to November 2018, 24 patients harboring cerebral arteriovenous malformations underwent endovascular embolization with Menox 18. Clinical features, angiographic results, procedural details, complications, and follow-up details were prospectively collected and retrospectively analyzed.

Results

Curative embolization in one endovascular session was achieved in 14/24 (58.3%) of the treated patients. Partial embolization was achieved in 10 patients (42.6%) in whom staged treatment with radiosurgery or microsurgical resection was planned. No mortality was recorded in our series. Clinical complications after embolization occurred in 1/24 (4.66%) patients. No technical complications were noted

Conclusions

Our pilot study suggests that the Menox embolization system offers similar technical and clinical results in comparison with the other currently available LEAs. Further studies with larger cohorts and long term follow-up data are needed to fully evaluate its efficacy

Surgical management of complex brain arteriovenous malformations with hybrid operating technique: study protocol of a prospective registry and a pragmatic clinical trial

BACKGROUND

Complex brain arteriovenous malformations (bAVMs) in ≥3 Spetzler-Martin grades have long been challenges among cerebrovascular diseases. None of the traditional methods, such as microsurgical operation, endovascular intervention, or stereotactic radiotherapy, can completely eliminate complex bAVMs without a risk of neural function deterioration. The multistaged hybrid operation solved part of the challenge but remained risky in the installment procedures and intervals. The one-staged hybrid operation was applied in the surgical treatment of cerebrovascular diseases and proved to be a potentially safe and effective method for curing complex bAVMs. However, lacking the support of high-level evidence, its advantages remain unclear. This study was proposed to validate the benefits and risks of one-staged hybrid operation in the treatment of complex bAVMs, as well as its indications, key technologies, and workflows.

METHODS

The study is being conducted from Jan 2016 to Dec 2020 with 20 cooperation centers. It consists of 2 sets. The registry set is designed as a prospective real-world registry. The trial set is designed as a prospective pragmatic clinical trial, specifically for the patients with perforating arterial feeders. The two sets share a common grouping: the traditional operation group and the one-staged hybrid operation group. The assignment is based on the clinical condition in the registry set and is randomized in the trial set. End points will be evaluated at scheduled time points. The safety and efficiency of one-staged hybrid operation in treating complex bAVMs will be validated.

DISCUSSION

The study is designed for a real-world exploration of benefits and risks of one-staged hybrid operation in the treatment of complex bAVMs. The two-set design reduces the compromise of clinical practice due to the study and improves the statistical power and research quality with a practical sample size. In the study, advantages of the one-staged hybrid operation will be evaluated and compared to those of traditional operation. A spanning development of neurosurgical operation might be facilitated by the study, which means a higher cure rate and lower disability rate in patients with complex bAVMs.

TRIAL REGISTRATION

The study was retrospectively registered in ClinicalTrials.gov ( NCT03774017 ) on 11th Dec, 2018.

Endovascular Treatment for Low-Grade (Spetzler-Martin I-II) Brain Arteriovenous Malformations

BACKGROUND AND PURPOSE

Surgical resection is usually considered as the first-line curative strategy for low-grade (Spetzler-Martin grade I-II) brain arteriovenous malformations because it has a high cure rate and low complications. The role of endovascular treatment remains to be clarified in this indication, especially after A Randomized Trial of Unruptured Brain Arteriovenous Malformations. Our objective was to assess the safety and efficacy of first-line endovascular treatment in low-grade brain arteriovenous malformation management at our institution.

MATERIALS AND METHODS

Patients with low-grade brain arteriovenous malformations treated primarily with embolization in our department between January 2005 and December 2015 were retrieved from our prospectively collected registry. The primary outcome was the brain arteriovenous malformation obliteration rate, and secondary outcomes were disability or death secondary to brain arteriovenous malformation embolization assessed through modification of the modified Rankin Scale.

RESULTS

Two hundred twenty-four patients completed endovascular treatment during the study period and represent our study population. Complete exclusion of brain arteriovenous malformations was achieved in 205 patients (92%), including 62.1% of brain arteriovenous malformation exclusions after a single endovascular treatment session. One patient died of a hemorrhagic complication after endovascular treatment, leading to a mortality rate of 0.4%. Twelve patients (5%) kept a permanent neurologic deficit secondary to a complication of the endovascular treatment. An overall good outcome (mRS 0-2) was reported in 179 patients (80%).

CONCLUSIONS

Endovascular treatment might be a suitable alternative to surgical resection for complete exclusion of selected low-grade brain arteriovenous malformations.

Usefulness of High-Resolution Three-Dimensional Multifusion Medical Imaging for Preoperative Planning in Patients with Cerebral Arteriovenous Malformation

BACKGROUND

Successful resection of arteriovenous malformation (AVM) depends on preoperative assessment of the detailed morphology of the AVM. Simultaneous detailed three-dimensional visualization of the feeding arteries, draining veins, and surrounding structures is needed. The aim of this study was to evaluate the usefulness of high-resolution three-dimensional multifusion medical imaging (HR-3DMMI) for preoperative planning of AVM resection.

METHODS

HR-3DMMI combined magnetic resonance imaging, magnetic resonance angiography, thin-slice computed tomography, and three-dimensional rotational angiography. Surface rendering was mainly used for creation of HR-3DMMI using multiple thresholds to create three-dimensional models. HR-3DMMI technique was used in 8 patients for preoperative planning, and imaging findings were compared with operative findings.

RESULTS

All feeding arteries and draining veins were found intraoperatively at the same position as estimated preoperatively and were occluded as planned preoperatively.

CONCLUSIONS

HR-3DMMI technique demonstrated the precise locations of feeding arteries, draining veins, and surrounding important tissues, such as corticospinal tract and arcuate fiber, preoperatively and estimated the appropriate route for resection of the AVM. HR-3DMMI is expected to be a very useful support tool for surgery of AVM.

Single-stage planning for total cure of grade III-V brain arteriovenous malformations by embolization alone or in combination with microsurgical resection

PURPOSE

There are no established guidelines for treatment of Spetzler-Martin grade III-V brain arteriovenous malformations (bAVMs). The purpose of this study is to report our institutional experience in total obliteration/eradication of grade III-V bAVMs by single-stage planning of embolization combined with microsurgical resection when necessary.

METHODS

All patients harboring Spetzler-Martin (S-M) grade III-V bAVMs treated with single-stage planning between January 2006 and January 2018 were retrospectively reviewed. This treatment paradigm is applicable only to surgically accessible bAVMs and does not include deep-seated bAVMs. Indications for treatment, clinical presentation, imaging characteristics, and treatment outcomes were analyzed. Outcomes were assessed based on modified Rankin Scale.

RESULTS

A total of 31 patients were identified. Seventeen patients (54.8%) presented with hemorrhage, 10 (32.3%) with seizures, 3 (9.7%) with headaches, and 1 (3.2%) with progressive neurological deficit. Based on S-M grading system, 25 patients (80.6%) harbored grade III bAVM, 5 patients had grade IV bAVMs (16.1%), and 1 patient (3.2%) had a grade V bAVM. There were no treatment-related complications in 24/31 (77.4%) patients. Of the total of seven patients with complications, four patients had clinical deterioration. The long-term (> 6-month), non-disabling morbidity (mRS ≤ 2) rate was 6.5%. The long-term, disabling morbidity rate was 3.2% with a mortality of 3.2%. Complete angiographic obliteration was achieved in 30/31 (96.8%) patients.

CONCLUSION

Single-stage treatment strategy can be considered as an alternative to multistage embolization prior to surgery in grade III-V bAVMs. In this study, a high rate of total obliteration with relatively low rates of permanent morbidity and mortality was achieved.

Bailout Strategies and Complications Associated with the Use of Flow-Diverting Stents for Treating Intracranial Aneurysms

Background

Flow-diverting stents (FDS) have revolutionized the endovascular management of unruptured, complex, wide-necked, and giant aneurysms. There is no consensus on management of complications associated with the placement of these devices. This review focuses on the management of complications of FDS for the treatment of intracranial aneurysms.

Summary

We performed a systematic, qualitative review using electronic databases MEDLINE and Google Scholar. Complications of FDS placement generally occur during the perioperative period.

Key Message

Complications associated with FDS may be divided into periprocedural complications, immediate postprocedural complications, and delayed complications. We sought to review these complications and novel management strategies that have been reported in the literature.

Ethylene vinyl alcohol copolymer for occlusion of specific portal branches during preoperative portal vein embolisation with n-butyl-cyanoacrylate

OBJECTIVES

To evaluate the safety and efficacy of ethylene vinyl alcohol copolymer (EVOH) injection for selective occlusion of portal branches considered at risk for non-target embolisation during preoperative portal vein embolisation (PVE).

METHODS

Twenty-nine patients (mean age, 57 ± 17 years) submitted to PVE with n-butyl-cyanoacrylate (NBCA) and additional EVOH for selected portal branches were retrospectively analysed. Indications for the use of EVOH and the selected portal branches were evaluated. Degree of hypertrophy of the future liver remnant (FLR) and kinetic growth were assessed by CT volumetry performed before and 3-6 weeks after PVE. Clinical outcome and histopathological analysis of portal veins occluded with EVOH were reviewed.

RESULTS

EVOH was indicated intraoperatively for embolisation of selected portal branches that the operator reported at risk to provoke non-target embolisation with NBCA. Indications for the use of EVOH were embolisation of segment IV (n = 21), embolisation of segmental portal branches with early bifurcation (n = 7) and PVE in a 1-year-old girl with cystic hamartomas. All targeted portal branches were successfully embolised. There were no cases with non-target embolisation by EVOH. The degree of hypertrophy of the FLR was 14.3 ± 8.1% and the kinetic growth rate was 2.7 ± 1.8% per week.

CONCLUSION

EVOH is safe and effective for embolisation of selected portal vein branches considered at risk for non-target embolisation.

KEY POINTS

• EVOH is another effective liquid embolic agent for preoperative PVE. • EVOH is relatively simple to handle with a minimal risk of non-target embolisation. • During PVE, some portal branches considered complicated to occlude with NBCA may be efficiently embolised with EVOH.

Cerebral arteriovenous malformations in the era of embolization for angiographic cure: a single-center experience in Egypt

Background

Embolization for cerebral arteriovenous malformations (AVMs) has evolved in the last decade with evolution in both equipment and material. Embolization targets have expanded to include angiographic cure.

Methods

To discuss the technical and management outcomes of our first cerebral AVM case series treated with embolization. The clinical, angiographic, treatment, and outcome variables of consecutive cerebral arteriovenous malformation cases, treated with curative embolization, between January 2011 and June 2017 in one regional center, were retrospectively analyzed.

Results

In 21 patients, 21 AVMs were identified, and 13 patients (61.9%) were males. The mean of the age was 34.24 ± 12.99. Fifteen patients (71.4%) had a history of intracranial hemorrhage, and 10 (47.6%) patients had seizures. Sixteen patients (76.2%) were at grade 1 of modified Rankin Scale (mRS) at admission. The median for modal Spetzler-Martin grade was 2. The average number of arterial feeders was 3. Direct arteriovenous fistulas were found in 4 cases (19.0%). Venous aneurysms were found in 4 cases (19.0%). Seventeen AVMs (80.9%) were considered high bleeding risk lesions. Forty-three embolization sessions were done. Early hemorrhage occurred in 3 sessions (7.0%). Vessel perforation occurred 1 session (2.3%). Poor outcome occurred in 1 patient that was discharged at grade 3 mRS. Angiographic cure was achieved in 9 patients (42.9%). The average size reduction was 65%.

Conclusions

Onyx embolization could serve as a curative option for AVM treatment with accepted morbidity and mortality.

Stereotactic radiosurgery alone or combined with embolization for brain arteriovenous malformations: a systematic review and meta-analysis

OBJECTIVE

Embolization of brain arteriovenous malformations (AVMs) prior to stereotactic radiosurgery (SRS) has been reported to negatively affect obliteration rates. The goal of this systematic review and meta-analysis was to compare the outcomes of AVMs treated with embolization plus SRS (E+SRS group) and those of AVMs treated with SRS alone (SRS group).

METHODS

A literature review was performed using PubMed to identify studies with 10 or more AVM patients and obliteration data for both E+SRS and SRS groups. A meta-analysis was performed to compare obliteration rates between the E+SRS and SRS groups.

RESULTS

Twelve articles comprising 1716 patients were eligible for analysis. Among the patients with radiological follow-up data, complete obliteration was achieved in 48.4% of patients (330/681) in the E+SRS group compared with 62.7% of patients (613/978) in the SRS group. A meta-analysis of the pooled data revealed that the obliteration rate was significantly lower in the E+SRS group (OR 0.51, 95% CI 0.41–0.64, p < 0.00001). Symptomatic adverse radiation effects were observed in 6.6% (27/412 patients) and 11.1% (48/433 patients) of the E+SRS and SRS groups, respectively. The annual post-SRS hemorrhage rate was 2.0%–6.5% and 0%–2.0% for the E+SRS and SRS groups, respectively. The rates of permanent morbidity were 0%–6.7% and 0%–13.5% for the E+SRS and SRS groups, respectively.

CONCLUSIONS

Arteriovenous malformation treatment with combined embolization and SRS is associated with lower obliteration rates than those with SRS treatment alone. However, this comparison does not fully account for differences in the initial AVM characteristics in the E+SRS group as compared with those in the SRS group. Further studies are warranted to address these limitations.

Rescue Therapy for Procedural Complications Associated With Deployment of Flow-Diverting Devices in Cerebral Aneurysms

Flow diverting devices (FDDs) have revolutionized the treatment of morphologically complex intracranial aneurysms such as wide-necked, giant, or fusiform aneurysms. Although FDDs are extremely effective, they carry a small yet significant risk of intraprocedural complications. As the implementation of these devices increases, the ability to predict and rapidly treat complications, especially those that are iatrogenic or intraprocedural in nature, is becoming increasingly more necessary.

Our objective in this paper is to provide a descriptive summary of the various types of intraprocedural complications that may occur during FDDs deployment and how they may best be treated. A systematic and qualitative review of the literature was conducted using electronic databases MEDLINE and Google Scholar. Searches consisted of Boolean operators “AND” and “OR” for the following terms in different combinations: “aneurysm,” “endovascular,” “flow diverter,” “intracranial,” and “pipeline.”

A total of 94 papers were included in our analysis; approximately 87 of these papers dealt with periprocedural endovascular (mainly related to FDDs) complications and their treatment; 7 studies concerned background material. The main categories of periprocedural complications encountered during deployment of FDDs are failure of occlusion, parent vessel injury and/or rupture, spontaneous intraparenchymal hemorrhage, migration or malposition of the FDDs, thromboembolic or ischemic events, and side branch occlusion

Periprocedural complications occur mainly due to thromboembolic events or mechanical issues related to device deployment and placement. With increasing use and expanding versatility of FDDs, the understanding of these complications is vital in order to effectively manage such situations in a timely manner.

Surgical Treatment of Arteriovenous Malformations: Role of Preoperative Staged Embolization

Preoperative embolization is complementary to surgery for large brain arteriovenous malformations (AVMs). From January 2005 to December 2015, 69 patients harboring an AVM were managed in our department by the same surgeon (RG). Forty one were ruptured and 65 were supratentorial. Thirty nine smaller AVMs were treated with surgery stand-alone, whereas, for 30 larger malformations, surgery was combined with adjuvant treatment involving preoperative staged embolization and/or, less frequently, radiosurgery. In all patients treated with surgery alone, complete resection of AVM was achieved. A successful preoperative partial endovascular obliteration of AVM was obtained in 24 out of 27 more complex cases, with a zero mortality rate and a very low morbidity. Here, embolization was of a certain utility in the handling of deeper feeders and nidus excision, also facilitating intraoperative hemostasis. In three cases of residuals, radiosurgery was performed. In those patient treated with a combined approach, a good overall outcome, 0-2 modified Rankin Scale (mRS), was achieved in 25 cases. Preoperative embolization proved to be a reasonable option complementary to high-grade AVMs surgery, reducing the frequency of breakthrough hemorrhages, aiding the elimination of deep feeders, and making the nidus dissection easier.

Endogenous hormone 2-methoxyestradiol suppresses venous hypertension-induced angiogenesis through up- and down-regulating p53 and id-1

Brain arteriovenous malformations (AVMs) which associate with angiogenesis due to local hypertension, chronic cerebral ischaemia and tissue hypoxia usually lead to haemorrhage, however, the therapeutic medicine for the disease is still lacking. 2‐methoxyestradiol (2‐ME) has been shown effective in the anti‐angiogenic treatment. This study was conducted to examine whether and how 2‐ME could improve the vascular malformations. Intracranial venous hypertension (VH) model produced in adult male Sprague‐Dawley rats and culture of human umbilical vein endothelial cells (HUVECs) at the anoxia condition were used to induce in vivo and in vitro angiogenesis, respectively. Lentiviral vectors of ID‐1 and p53 genes and of their siRNA were intracranially injected into rats and transfected into HUVECs to overexpress and down‐regulate these molecules. 2‐ME treatment not only reduced the in vivo progression of brain tissue angiogenesis in the intracranial VH rats and the in vitro increases in microvasculature formation, cellular migration and HIF‐1α expression induced by anoxia in HUVECs but also reversed the up‐regulation of ID‐1 and down‐regulation of p53 in both the in vivo and in vitro angiogenesis models. All of the anti‐angiogenesis effects of 2‐ME observed in VH rats and anoxic HUVECs were abrogated by ID‐1 overexpression and p53 knockdown. Our data collectively suggest that 2‐ME treatment inhibits hypoxia/anoxia‐induced angiogenesis dependently on ID‐1 down‐regulation and p53 up‐regulation, providing a potential alternative medical treatment for un‐ruptured AVM patients.

Timing of surgery for ruptured supratentorial arteriovenous malformations

BACKGROUND

There are conflicting opinions regarding the optimal waiting time to perform surgery after rupture of supratentorial arteriovenous malformations (AVMs) to achieve the best possible outcome.

OBJECTIVE

To analyze factors influencing outcomes for ruptured supratentorial AVMs after surgery, paying particular attention to the timing of the surgery.

METHODS

We retrospectively investigated 59 patients admitted to our center between 2000 and 2014 for surgical treatment of ruptured supratentorial AVMs. We evaluated the effect of timing of surgery and other variables on the outcome at 2-4 months (early outcome), at 12 months (intermediate outcome) after surgery, and at final follow-up at the end of 2016 (late outcome).

RESULTS

Age over 40 years (OR 18.4; 95% CI 1.9-172.1; p = 0.011), high Hunt and Hess grade (4 or 5) before surgery (OR 13.5; 95% CI 2.1-89.2; p = 0.007), hydrocephalus on admission (OR 12.9; 95% CI 1.8-94.4; p = 0.011), and over 400 cm³ bleeding during surgery (OR 11.5; 95% CI 1.5-86.6; p = 0.017) were associated with an unfavorable early outcome. Age over 40 years (OR 62.8; 95% CI 2.6-1524.9; p = 0.011), associated aneurysms (OR 34.7; 95% CI 1.4-829.9; p = 0.029), high Hunt and Hess grade before surgery (OR 29.2; 95% CI 2.6-332.6; p = 0.007), and over 400 cm³ bleeding during surgery (OR 35.3; 95% CI 1.7-748.7; p = 0.022) were associated with an unfavorable intermediate outcome. Associated aneurysms (OR 8.2; 95% CI 1.2-55.7; p = 0.031), high Hunt and Hess grade before surgery (OR 5.7; 95% CI 1.3-24.3; p = 0.019), and over 400 cm³ bleeding during surgery (OR 5.8; 95% CI 1.2-27.3; p = 0.027) were associated with an unfavorable outcome at last follow-up. Elapsed time between rupture and surgery did not affect early or final outcome.

CONCLUSIONS

Early surgery in patients with ruptured supratentorial arteriovenous malformation is feasible strategy, with late results comparable to those achieved with delayed surgery. Many other factors than timing of surgery play significant roles in long-term outcomes for surgically treated ruptured supratentorial AVMs.

Treatment Outcomes of A Randomized Trial of Unruptured Brain Arteriovenous Malformation-Eligible Unruptured Brain Arteriovenous Malformation Patients

BACKGROUND

The guideline for treating unruptured brain arteriovenous malformations (ubAVMs) remains controversial. A Randomized Trial of Unruptured Brain Arteriovenous Malformations (ARUBA) reported lower risk of stroke or death with conservative management compared to interventional treatment. There were numerous limitations to the study, including short follow-up period and disproportionate number of patients treated with surgery and embolization.

OBJECTIVE

To evaluate whether treatment of ARUBA-eligible patients have acceptable outcomes at our institution.

METHODS

Retrospective analysis was performed on 673 patients with brain AVMs treated at our institution between 2001 and 2014. One hundred five patients were ARUBA eligible and included in the study. Patients were divided into the microsurgery or Gamma Knife Radiosurgery (GKS; Elekta, Stockholm, Sweden) arm depending on their final treatment. Mean follow-up period was 43 mo (range 4-136 mo). Primary outcome was stroke or death.

RESULTS

A total of 8 (7.6%) patients had a stroke or died. The overall risk of stroke or death was 11.4% (5 of 44 patients) for the microsurgery arm and 4.9% (3 of 61 patients) for the GKS arm. The annual rates of stroke or death were 2.1%, 4.0%, and 1.2% for the entire patient cohort, microsurgery arm, and GKS arm, respectively. AVM obliteration rates at the end of the follow-up period were 95.5% and 47.5% for the microsurgery and GKS arms, respectively.

CONCLUSION

We report a lower overall risk of stroke or death in our ARUBA-eligible patients following treatment than ARUBA. Our results suggest that microsurgery and GKS may be appropriate treatments for patients with ubAVM.