Cerebral arteriovenous malformations: evaluation and management

From Diagnosis to Complication: A Detailed Case Analysis on the Journey of Managing Medial Tentorial Dural Arteriovenous Fistula

Tentorial dural arteriovenous fistulas (DAVFs) are rare but highly dangerous vascular anomalies, constituting a small percentage of all intracranial DAVFs. Despite their infrequency, these lesions display aggressive characteristics, frequently leading to hemorrhage or neurological deficits due to their retrograde drainage into leptomeningeal veins, thus classifying them as Borden type III lesions. This case presents a middle-aged man who suffered cerebellar and subarachnoid hemorrhages resulting from a medial tentorial DAVF. Initial imaging revealed a high-flow vascular lesion, which was subsequently confirmed through angiography. Endovascular embolization targeted the right middle meningeal artery, showing initial improvement. However, the patient experienced a notable decline two days later, attributed to residual or recurrent fistulas, venous hypertension, and cerebral edema. Effective management of tentorial DAVFs necessitates a multidisciplinary approach, combining endovascular, surgical, and occasionally radiosurgical techniques. Continuous monitoring is essential for early detection and management of complications. This case underscores the critical need for a comprehensive strategy to manage the high risks associated with these vascular anomalies and to prevent potentially life-threatening outcomes.

Wyburn-Mason Syndrome: A Narrative Review

Wyburn-Mason syndrome is a rare congenital disorder characterized by arteriovenous malformations (AVMs) in the retina, brain, and occasionally the skin. The syndrome results from embryonic vascular abnormalities and presents with a wide spectrum of clinical manifestations, classified into three groups based on severity. Diagnosis relies heavily on imaging techniques, with optical coherence tomography (OCT) and cerebral angiography playing crucial roles. Management is typically conservative due to the stability of most AVMs, but intervention may be necessary when the rupture risk of intracranial AVMs exceeds 2.2% per year. Treatment options include endovascular embolization, surgical resection, and emerging therapies like intravitreal injections. This review emphasizes the importance of a multidisciplinary approach involving ophthalmologists, neurologists, and interventional radiologists, as well as regular monitoring of asymptomatic AVMs to optimize patient outcomes and quality of life.

Multistaged Stereotactic Radiosurgery for Complex Large Lobar Arteriovenous Malformations: A Case Series

BACKGROUND AND OBJECTIVES

Although stereotactic radiosurgery (SRS) has well defined outcomes in the management of smaller-volume arteriovenous malformations (AVM), this report evaluates the outcomes when SRS is used for large-volume (≥10 cc) lobar AVMs.

METHODS

Between 1990 and 2022, a cohort of 1325 patients underwent Leksell Gamma Knife SRS for brain AVMs. Among these, 40 patients (25 women; median age: 37 years) with large lobar AVMs underwent volume-staged SRS followed by additional SRS procedures if needed (2-5 procedures). The patients presented with diverse AVM locations and Spetzler-Martin Grades. Before SRS, 16 patients underwent a total of 43 embolization procedures.

RESULTS

Over a median follow-up of 73 months, 20 patients achieved AVM obliteration. The 3, 5, and 10-year obliteration rates were 9.3%, 15.3%, and 53.3%, respectively. During the latency interval between the first SRS procedure and the last follow-up, 11 patients had intracerebral hemorrhages (ICH) and 6 developed new neurological deficits unrelated to ICH. The postoperative hemorrhage risk after the first SRS was 13.8% at 3 years, 16.6% at 5 years, and 36.2% at 10 years. No hemorrhagic event was documented after confirmed obliteration. Compared with the modified Rankin Scale (mRS) scores before SRS, the mRS improved or remained stable in 28 patients. Nine patients died during the observation interval. Five were related to ICH.

CONCLUSION

These outcomes underscore both the potential effectiveness and the limitations of multistage SRS procedures for complex high-risk large volume AVMs in critical brain lobar locations. Most patients retained either stable or improved long-term mRS scores. During the latency interval from the first SRS until obliteration, achieved after two or more procedures, the risk of hemorrhage and treatment-related complications persists.

The current landscape of machine learning-based radiomics in arteriovenous malformations: a systematic review and radiomics quality score assessment

Background

Arteriovenous malformations (AVMs) are rare vascular anomalies involving a disorganization of arteries and veins with no intervening capillaries. In the past 10 years, radiomics and machine learning (ML) models became increasingly popular for analyzing diagnostic medical images. The goal of this review was to provide a comprehensive summary of current radiomic models being employed for the diagnostic, therapeutic, prognostic, and predictive outcomes in AVM management.

Methods

A systematic literature review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines, in which the PubMed and Embase databases were searched using the following terms: (cerebral OR brain OR intracranial OR central nervous system OR spine OR spinal) AND (AVM OR arteriovenous malformation OR arteriovenous malformations) AND (radiomics OR radiogenomics OR machine learning OR artificial intelligence OR deep learning OR computer-aided detection OR computer-aided prediction OR computer-aided treatment decision). A radiomics quality score (RQS) was calculated for all included studies.

Results

Thirteen studies were included, which were all retrospective in nature. Three studies (23%) dealt with AVM diagnosis and grading, 1 study (8%) gauged treatment response, 8 (62%) predicted outcomes, and the last one (8%) addressed prognosis. No radiomics model had undergone external validation. The mean RQS was 15.92 (range: 10-18).

Conclusion

We demonstrated that radiomics is currently being studied in different facets of AVM management. While not ready for clinical use, radiomics is a rapidly emerging field expected to play a significant future role in medical imaging. More prospective studies are warranted to determine the role of radiomics in the diagnosis, prediction of comorbidities, and treatment selection in AVM management.

A Review of the Current State and Future Directions for Management of Scalp and Facial Vascular Malformations

Vascular malformations are structural abnormalities that are thought to result from errors in vasculogenesis and angiogenesis during embryogenesis. Vascular malformations of the scalp present unique management challenges due to aesthetic and functional implications. This review examines the pathophysiology, clinical presentation, and management techniques for six common types of vascular malformations of the face and scalp : infantile hemangioma, capillary malformations, venous malformations, lymphatic malformations, arteriovenous malformations, and arteriovenous fistulas. These lesions range from common to rare, and have very different natural histories and management paradigms. There has been increasing understanding of the molecular pathways that are altered in association with these vascular lesions and these molecular targets may represent novel strategies of treating lesions that have historically been approached from a structural perspective only.

Partial Endovascular Embolization of a Cerebral Arteriovenous Malformation in a Patient With Seizures Caused by a Steal Phenomenon: A Case Analysis

Cerebral arteriovenous malformations (cAVMs) are developmental pathologic lesions of the blood vessels of the brain in which multiple arteries shunt blood directly into the venous drainage network. They are lesions with an unclear etiology and, if left untreated, can bear significant risks of complications such as migraines, seizures, neurological deficits, and intracranial hemorrhages. The diagnosis is based on several imaging methods, with angiography being the primary method. Treatment modalities include microsurgery, radiosurgery, embolization with the intent of obliteration, and various multidisciplinary approaches. We aim to introduce the case of an adult female patient with symptomatic cAVM who underwent partial endovascular embolization of the lesion and evaluate her recovery and the overall reliability of her treatment modality. A 22-year-old female patient has presented to the Neurosurgery Clinic with clinical manifestations with photosensitive seizures, migraines, and a history of sleep disturbances persisting for a period of one year. An appointed MRI and angiography revealed the presence of a glomerular cAVM of the anterior parietal branch of the middle cerebral artery located within the intraparietal sulcus of the left cerebral hemisphere (Spetzler-Martin grade 2). The venous drainage of the malformation led to a loss of nutrients in the surrounding brain parenchyma (a steal phenomenon), causing the seizures. The patient successfully underwent transarterial endovascular embolization with Onyx, which proved to be partial on a postoperative angiography, and refused further embolization procedures. There were no postoperative complications to be mentioned. The patient reported no seizures or sleep disturbances at the 12-month follow-up, with sporadic weak headaches remaining. cAVMs remain a pathology with significant morbidity and mortality when undiagnosed. Symptomatic cAVMs leading to a steal phenomenon and seizures can be reliably managed via endovascular embolization alone when the malformation has an appropriate angioarchitecture, location, size, and a low Spetzler-Martin score. However, further inquiry is required into the use of partial embolization in cases where further multiple-stage embolization procedures are declined and/or complete occlusion of the lesion is unfeasible. This case report emphasizes that partial endovascular embolization can be successfully utilized as a treatment modality for the symptoms caused by a steal phenomenon of the venous drainage of a cAVM, such as seizure disorders and migraines, in the rare instance when multiple-stage embolization is declined by the patient and occlusion of the lesion remains subtotal.

Preradiosurgical Embolization of Arteriovenous Malformations Reduces Target Volume - The Main Determinant for Complete Obliteration

BACKGROUND

Embolization and stereotactic radiosurgery (SRS) have increasingly been used to treat complex arteriovenous malformations (AVMs). We studied outcomes of AVM patients treated through a multidisciplinary approach, examined the effect of embolization on SRS success, and analyzed predictors of treatment failure.

METHODS

We retrospectively reviewed a prospectively maintained database of patients with AVMs treated with Gamma Knife (Leksell) SRS over an 11-year period. Patients with incomplete medical records and follow-up <2 years were excluded. Demographics, clinical presentation, previous rupture history, angiographic nidus size, Spetzler-Martin (S-M) grade, adjunctive endovascular embolization and microsurgical resection, radiologic evidence of obliteration and hemorrhage, and clinical outcomes (modified Rankin Scale [mRS] scores) were recorded. Radiosurgery-related details including nidus volume and number of sessions and radiosurgery-, embolization-, and resection-associated complications were also recorded.

RESULTS

Eighty-three patients (mean age, 41.0 ± 21.3 years) were included. Mean reduction in AVM nidus target volume with endovascular embolization was 66.0 ± 19.7%. S-M grade reduction was achieved in 51.6% cases. Total obliteration after SRS was achieved in 56 AVMs (67.5%) after 2 years, and in 38 (86.4%) after 4 years. Two (2.4%) patients had rehemorrhage after SRS. Overall complication rate was 3.6%. Median angiographic follow-up was 55.5 months. Favorable outcomes (mRS = 0-2) were seen in 77.1%. SRS target volume was an independent predictor of treatment failure regardless of pre-SRS embolization.

CONCLUSIONS

High AVM obliteration rates were achieved with judicious use of radiosurgery alone or with embolization. Embolization reduced target nidus volume by an average of 66%. SRS target volume was an independent predictor of treatment failure.

Cerebral Arteriovenous Malformation With Ipsilateral Middle Cerebral Artery Occlusion: A Case Report

We report the case of a 29-year-old man who presented with a sudden headache. Computed tomography showed a small intraventricular hemorrhage in the left lateral ventricle. Cerebral angiograms suggested rupture of a coexisting feeder aneurysm in the left temporal cerebral arteriovenous malformation (AVM). The left proximal middle cerebral artery, a major feeding artery, was occluded near the AVM, with development of abnormal blood supply, such as in moyamoya-like vessels to the nidus. After endovascular embolization of the coexisting feeder aneurysm and feeding arteries, the patient underwent volume-staged Gamma Knife radiosurgery (GKS). Follow-up angiograms performed 4.5 years after the last GKS confirmed complete disappearance of the AVM. Around 4.8 years after GKS, the patient required surgical intervention to develop delayed cyst formation; however, the postoperative course was uneventful.

Etiologies of Brain Arteriovenous Malformation Recurrence: A Focus on Pediatric Disease

Pediatric brain arteriovenous malformations are a major cause of morbidity and mortality, with the harmful effects of this disease compounded by the additional disability-years experienced by children with ruptured or other symptomatic arteriovenous malformations. In addition to the risks shared with their adult counterparts, pediatric patients frequently experience recurrence following radiographic cure, which presents an additional source of morbidity and mortality. Therefore, there is a need to synthesize potential mechanisms contributing to the elevated recurrence risk in the pediatric population and discuss how these translate to practical considerations for managing these patients.

Bleeding pediatric AVM with negative pre-operative angiography: the first case report

INTRODUCTION

Pediatric arteriovenous malformation (pAVM) is one of the most common vascular entities in non-traumatic intracerebral hemorrhage (ICH) in children. To diagnose arteriovenous malformation (AVM), digital subtraction angiography (DSA) is the gold standard investigation because it can provide sufficient dynamic information about the AVM. In extremely rare occasions, angiography is unable to detect an AVM because the AVM is spontaneously occluded. All reported cases found by authors in the literature had already been diagnosed with AVM by angiography or other vascular studies before the AVM occlusion.

CASE PRESENTATION

We present a case of a 4-year-old girl who presented with left occipital ICH with atypical calcification. Based on history and investigation, pAVM was the most likely diagnosis. However, preoperative angiography was negative for pAVM and for shunting. Bleeding tumor was then suspected instead. After resection, pathological diagnosis confirmed pAVM.

CONCLUSION

Our case demonstrates that DSA, despite being considered the gold standard, cannot always diagnose pAVM. The mechanism of spontaneous AVM occlusion remains unknown.

Intraparenchymal cerebellar capillary hemangioma in a 32-year-old man: a case report

The authors present an unusual case of a 32-year-old adult male with a capillary hemangioma, which developed within the left cerebellar parenchyma. The histopathological examination reveals a mass mostly formed by the proliferation of capillaries, lined by a layer of flat-plump endothelial cells, some branching and dilating large capillaries, forming a lobulated structure separated by fibrocollagenous connective tissue. Immunohistochemistry examination with CD31 and S100 was positive on the endothelial and stromal cells, respectively, and negative S100 on the endothelial cells. Although rare, capillary hemangioma should be one of the differential diagnoses for diagnosing intra-axial lesions in the cerebellar region. Confirmation of the histopathological characteristic is necessary to determine the diagnosis of capillary hemangioma and exclude other differential diagnoses.

Arteriovenous Malformations: An Update on Models and Therapeutic Targets

Arteriovenous malformations (AVMs) are an anomaly of the vascular system where feeding arteries are directly connected to the venous drainage network. While AVMs can arise anywhere in the body and have been described in most tissues, brain AVMs are of significant concern because of the risk of hemorrhage which carries significant morbidity and mortality. The prevalence of AVM's and the mechanisms underlying their formation are not well understood. For this reason, patients who undergo treatment for symptomatic AVM's remain at increased risk of subsequent bleeds and adverse outcomes. The cerebrovascular network is delicate and novel animal models continue to provide insight into its dynamics in the context of AVM's. As the molecular players in the formation of familial and sporadic AVM's are better understood, novel therapeutic approaches have been developed to mitigate their associated risks. Here we discuss the current literature surrounding AVM's including the development of models and therapeutic targets which are currently being investigated.

Chronic Encapsulated Expanding Hematomas After Stereotactic Radiosurgery for Intracranial Arteriovenous Malformations: An International Multicenter Case Series

BACKGROUND

Stereotactic radiosurgery (SRS) offers a minimally invasive treatment modality for appropriately selected intracranial arteriovenous malformations (AVMs). Recent reports have described the development of rare, delayed chronic encapsulated expanding hematomas (CEEHs) at the site of an angiographically confirmed obliterated AVM.

OBJECTIVE

To elucidate the incidence, characteristics, and management of CEEH in patients with AVM after SRS.

METHODS

The records of all patients who underwent SRS for an intracranial AVM at 4 institutions participating in the International Radiosurgery Research Foundation between 1987 and 2021 were retrospectively reviewed. Data regarding characteristics of the AVM, SRS treatment parameters, CEEH presentation, management, and outcomes were collected and analyzed.

RESULTS

Among 5430 patients, 15 developed a CEEH at a crude incidence of 0.28%. Nine patients were female, and the mean age was 43 ± 14.6 years. Nine patients underwent surgical evacuation, while 6 were managed conservatively. The median CEEH development latency was 106 months after SRS. The patients were followed for a median of 32 months, and 9 patients improved clinically, while 6 patients remained stable. No intraoperative complications were reported after CEEH resection, although 1 patient recovered from postoperative meningitis requiring intravenous antibiotics.

CONCLUSION

CEEH is a rare, late complication of AVM SRS with an incidence of 0.28% and a median latency of 106 months. In the presence of a delayed and symptomatic expanding hematoma in the bed of an angiographically obliterated AVM, surgical resection resulted in clinical improvement in most patients. Conservative management is possible in asymptomatic patients with stable, small-sized hematomas in deeply seated locations.

Atypical slow-flow paramedian AVM with venous varix

Background:

Cerebral arteriovenous malformations (CAVMs) are either clinically silent or symptomatic. The most common presentation in more than half of all CAVMs presenting patients is hemorrhage which is accompanied by long-standing neurological morbidity and mortality. This report presents a case of an atypical large, slow-flow paramedian AVM with a dilated venous varix managed with surgery. The impact of the intraoperative findings on the diagnosis and the operative technique will be discussed.

Case Description:

In otherwise, healthy 26-year-old male complained of repeated episodes of generalized seizures and loss of consciousness. Brain magnetic resonance imaging (MRI) revealed a right parietal paramedian arteriovenous malformation (AVM) with signs of an old hemorrhagic cavity beneath it. Digital subtraction angiography demonstrated a slow-filling AVM with dilated venous varix drains into the superior sagittal sinus. However, the exact point of drainage cannot be appreciated. The filling of the AVM occurred precisely with the beginning of the venous phase. Intraoperatively, we noticed a whitish spherical mass, thick hemosiderin tissue, and a large cavity below the nidus; then, a complication-free complete microsurgical resection of this high-grade AVM was performed. Postoperatively, the patient suffered two attacks of seizures in the first few hours after the surgery, for which he received antiepileptics. MRI was clear during follow-up, and the patient was seizure-free and neurologically intact.

Conclusion:

Parietal convexity AVMs are challenging lesions to tackle. However, the chronicity and the slow-filling of the AVM, in this case, can render the surgical pathway more direct and accessible.

How we approach localized vascular anomalies

Vascular anomalies are a group of disorders divided into two distinct subtypes: vascular tumors and vascular malformations. Vascular tumors are proliferative in nature, while malformations are nonproliferative. Simple, localized vascular malformations refer to a group of malformations that are localized to a single area of involvement. These simple malformations include capillary, lymphatic, venous, and arteriovenous malformations. The pediatric hematologists and oncologists are becoming increasingly involved in the diagnosis and management of these disorders. This review presents four cases as a means to discuss the diagnosis, clinical and imaging features, and management strategies of simple, localized vascular malformations.

Emerging Polymer Materials in Trackable Endovascular Embolization and Cell Delivery: From Hype to Hope

Minimally invasive endovascular embolization is a widely used clinical technique used for the occlusion of blood vessels to treat various diseases. Different occlusive agents ranging from gelatin foam to synthetic polymers such as poly(vinyl alcohol) (PVA) have been commercially used for embolization. However, these agents have some drawbacks, such as undesired toxicity and unintended and uncontrolled occlusion. To overcome these issues, several polymer-based embolic systems are under investigation including biocompatible and biodegradable microspheres, gelling liquid embolic with controlled occlusive features, and trackable microspheres with enhanced safety profiles. This review aims to summarize recent advances in current and emerging polymeric materials as embolization agents with varying material architectures. Furthermore, this review also explores the potential of combining injectable embolic agents and cell therapy to achieve more effective embolization with the promise of outstanding results in treating various devastating diseases. Finally, limitations and challenges in developing next-generation multifunctional embolic agents are discussed to promote advancement in this emerging field.

Digital subtraction angiography in cerebrovascular disease: current practice and perspectives on diagnosis, acute treatment and prognosis

Digital Subtraction Angiography (DSA) is the gold-standard imaging modality in acute cerebrovascular diagnosis. The role of DSA has become increasingly prominent since the incorporation of endovascular therapy in standards of care for acute ischemic stroke. It is used in the assessment of cerebral vessel patency; however, the therapeutic role of DSA from a prognostic standpoint merits further investigation. The current paper provides an update on current practice on diagnostic, therapeutic and prognostic use of DSA in acute cerebrovascular diseases and various indications and perspectives that may apply, or limit its use, in ongoing surveillance or prognosis. Pre-clinical and clinical studies on the aspects, including but not limited to the morphology of cerebrovasculature in acute ischaemic stroke, are required to delineate and inform its prognostic role.

Intracranial calcification in venous congestion

Background

Intracranial calcification is a common finding on brain imaging which can be non-specific. The calcification can be physiological or pathological. Likewise, subcortical calcification is a non-specific finding on non-contrast-enhanced computed tomography. This could be secondary to multiple underlying diseases such as Sturge-Weber syndrome, tuberous sclerosis, Fahr disease, post-chemoradiotherapy change, and metabolic disorders secondary to parathyroid or thyroid gland abnormalities. On the other hand, subcortical calcification secondary to arteriovenous malformation and dural venous fistula are uncommon findings. We report two cases with subcortical calcification secondary to these vascular malformations. We aim to highlight the importance of recognising subcortical calcification as one of the possible imaging appearances of dural venous fistula and arteriovenous malformation.

Case presentation

We report two cases, whom were a 45-year-old lady and a 20-year-old man, with subcortical calcification on non-contrast-enhanced computed tomography, which were later confirmed to be secondary to chronic venous congestion as the results of dural venous fistula and arteriovenous malformation, respectively. Both patients underwent magnetic resonance imaging of the brain and digital substraction angiography to confirm the diagnosis. Subsequently, both patients were offered embolisation with the 45-year-old lady opting for conservative management and the 20-year-old man waiting for the procedure, at the time of writing.

Conclusion

Venous congestion secondary to intracranial vascular malformation is an important differential diagnosis for extensive subcortical and basal ganglia calcification. Knowledge on the possibility of vascular malformation to present with subcortical calcification is crucial to avoid misdiagnosis and mismanagement of the patients.

Endovascular embolization for cases of 'hidden' pediatric cerebral arteriovenous malformations: A diagnostic & therapeutic challenge

BACKGROUND

Ruptured arteriovenous malformations (AVM) hold a larger proportion as the cause of spontaneous intracranial hemorrhage in children compared to those in adults. Although surgical excision still remains as the gold standard therapy for arteriovenous malformations, some smaller ones are reported to resolve from embolization alone. However, difficulty arises when small arteriovenous malformations are not detected on certain diagnostic modalities such as Computed Tomography Angiography (CTA), giving rise to false negatives, which may compromise appropriate management of patients. Endovascular embolization can be used as alternative options as diagnostic and therapy for invisible arteriovenous malformation in children. We report two cases of ruptured paediatrics arteriovenous malformations with a complication of hydrocephalus, managed with endovascular embolization and a cerebrospinal fluid diversionary procedure.

CASE DESCRIPTION

We report 2 case in from Dr. Soetomo academic general hospital in 2021, the first case was a fully conscious 6-year-old-female child with sudden left-sided weakness and severe headache in January, and the second case a 9-year-old female came with decreased consciousness in May. Both had evidence of intracerebral hemorrhage, intraventricular hemorrhage, and hydrocephalus on head radiological examination, but no visible vascular malformations on Computed Tomography Angiography. The first patient was treated with extra ventricular drainage initially, while the second case was not. Transfemoral cerebral angiography revealed small arteriovenous malformations in both patients, and both had successful endovascular embolization afterwards. The first case was shunt-free, while the second case had her drainage switched to ventriculoperitoneal shunt right after the embolization procedure. Both patients recovered fully without complications and sequelae, and were discharged afterwards.

DISCUSSION

Both patients did not undergo surgical resection of the arteriovenous malformations; the first case only underwent endovascular embolization, while the second case underwent embolization and ventriculoperitoneal shunting. The cases described here help highlight the irreplaceable role of Transfemoral Cerebral Angiography as a gold standard for cases for arteriovenous malformations compared to other modalities, such as Computed Tomography Angiography (CTA). Smaller arteriovenous malformations in paediatrics are reported to achieve complete radiological resolution, and cerebrospinal fluid diversion in hydrocephalic cases are not always performed. Several factors to be considered include initial consciousness and severity of neurological deficit, which were taken into account in the management of our patients.

CONCLUSION

Embolization procedures may be beneficial in some pediatric arteriovenous malformations, preferably in smaller ones that undetectable by angiography. Several factors such as the consciousness and neurological deficit upon initial presentation may help in the decision making of these cases.

Axis fracture due to giant cranial AVM

Cerebral arteriovenous malformations (AVMs) are a vascular anomaly consisting of a bundle of direct connection of arteries and veins. AVMs clinical expression ranges from complete asymptomatic, and thus incidentally found, to life threatening with rupturing and bleeding. In this wide spectrum, osteolysis is considered as a rare complication of interosseous AVMs, and only few cases of mandible and maxilla osteolysis have been reported. We present, herein, a case of an intracranial AVM, which has caused in the course of the time an osteolysis of the dens and axis.

Simulation of superselective catheterization for cerebrovascular lesions using a virtual injection software

Background

This report addresses the feasibility of virtual injection software based on contrast-enhanced cone-beam CTs (CBCTs) in the context of cerebrovascular lesion embolization. Intracranial arteriovenous malformation (AVM), dural arteriovenous fistula (AVF) and mycotic aneurysm embolization cases with CBCTs performed between 2013 and 2020 were retrospectively reviewed. Cerebrovascular lesions were reviewed by 2 neurointerventionalists using a dedicated virtual injection software (EmboASSIST, GE Healthcare; Chicago, IL). Points of Interest (POIs) surrounding the vascular lesions were first identified. The software then automatically displayed POI-associated vascular traces from vessel roots to selected POIs. Vascular segments and reason for POI identification were recorded. Using 2D multiplanar reconstructions from CBCTs, the accuracy of vascular traces was assessed. Clinical utility metrics were recorded on a 3-point Likert scale from 1 (no benefit) to 3 (very beneficial).

Results

Nine cases (7 AVM, 1 AVF, 1 mycotic aneurysm) were reviewed, with 26 POIs selected. Three POIs were in 2nd order segments, 8 POIs in 3rd order segments and 15 POIs in 4th order segments of their respective arteries. The reviewers rated all 26 POI traces – involving a total of 90 vascular segments – as accurate. The average utility score across the 8 questions were 2.7 and 2.8 respectively from each reviewer, acknowledging the software’s potential benefit in cerebrovascular embolization procedural planning.

Conclusion

The operators considered CBCT-based virtual injection software clinically useful and accurate in guiding and planning cerebrovascular lesion embolization in this retrospective review. Future prospective studies in larger cohorts are warranted for validation of this modality.

Aberrant regulation of retinoic acid signaling genes in cerebral arterio venous malformation nidus and neighboring astrocytes

BACKGROUND

Cerebral arterio venous malformations (AVM) are a major causal factor for intracranial hemorrhage, which result in permanent disability or death. The molecular mechanisms of AVM are complex, and their pathogenesis remains an enigma. Current research on cerebral AVM is focused on characterizing the molecular features of AVM nidus to elucidate the aberrant signaling pathways. The initial stimuli that lead to the development of AVM nidus structures between a dilated artery and a vein are however not known.

METHODS

In order to understand the molecular basis of development of cerebral AVM, we used in-depth RNA sequencing with the total RNA isolated from cerebral AVM nidus. Immunoblot and qRT-PCR assays were used to study the differential gene expression in AVM nidus, and immunofluorescence staining was used to study the expression pattern of aberrant proteins in AVM nidus and control tissues. Immunohistochemistry was used to study the expression pattern of aberrant proteins in AVM nidus and control tissues.

RESULTS

The transcriptome study has identified 38 differentially expressed genes in cerebral AVM nidus, of which 35 genes were upregulated and 3 genes were downregulated. A final modular analysis identified an upregulation of ALDH1A2, a key rate-limiting enzyme of retinoic acid signaling pathway. Further analysis revealed that CYR61, a regulator of angiogenesis, and the target gene for retinoic acid signaling is upregulated in AVM nidus. We observed that astrocytes associated with AVM nidus are abnormal with increased expression of GFAP and Vimentin. Triple immunofluorescence staining of the AVM nidus revealed that CYR61 was also overexpressed in the abnormal astrocytes associated with AVM tissue.

CONCLUSION

Using high-throughput RNA sequencing analysis and immunostaining, we report deregulated expression of retinoic acid signaling genes in AVM nidus and its associated astrocytes and speculate that this might trigger the abnormal angiogenesis and the development of cerebral AVM in humans.

Embolic Agents and Microcatheters for Endovascular Treatment of Cerebral Arteriovenous Malformations

Endovascular embolization of cerebral arteriovenous malformations (AVMs) originally entailed delivery of N-butyl cyanoacrylate glue to the nidus via a flow-directed microcatheter. Within the past decade, several new liquid embolic agents and novel microcatheter technologies have become available that have improved the ease of use and efficacy of endovascular therapies for AVMs. Nonadhesive copolymers, such as Onyx and Precipitating Hydrophobic Injectable Liquid, have largely replaced N-butyl cyanoacrylate given a lower risk of catheter entrapment. The emergence of balloon microcatheters has allowed for improved protection of the normal cerebral vasculature and has improved the penetration of liquid embolics into large AVMs, ultimately reducing procedure times and radiation exposure. Finally, several detachable tip microcatheters have been developed to facilitate removal of the catheter from hardened liquid embolic cast, preventing the morbidity associated with distal catheter entrapment. This article reviews the embolic agents and microcatheters currently available for the treatment of cerebral AVMs in the United States as well as the data demonstrating the safety and efficacy of these devices.

Pre-Surgical Endovascular Proximal Feeder Artery Devascularization Technique for the Treatment of Cranial Arteriovenous Malformations

Objective

Treatment of brain arteriovenous malformations (AVMs) aims to abolish any risk for intracranial hemorrhage with the preservation of the patient’s functional status. We present the technique of pre-surgical endovascular devascularization through proximal feeder artery occlusion for the treatment of cranial AVMs rather than nidus occlusion. Also, we highlight the advantages and the possible clinical indications.

Patients and Methods

Two patients with brain AVM and one patient with scalp AVM were treated by pre-surgical endovascular devascularization followed by surgical resection. Endovascular devascularization was performed by occlusion of the AVM feeders only with Liquid Embolic System Agent (Onyx^®) 18 without entering and filling the nidus. During surgery, feeding arteries colored with the black color of the Liquid Embolic System Agent were clearly identified and cut. Dissection of the AVM was performed, and resection of the nidus was achieved.

Results

Total resection of the AVM was achieved in all cases confirmed with follow-up angiographies, with no neurologic or systemic complications. Also, no major bleeding was detected. In addition, the surgical clips were avoided during surgery. Brain AVMs were safely resected in piecemeal fashion.

Conclusion

Pre-surgical endovascular proximal feeder artery devascularization technique shows to be a safe, simple and effective technique for the management of cranial arteriovenous malformations. This technique simplifies both the endovascular and surgical approaches to complicated cranial AVM cases.

Comprehensive analysis of dysregulated exosomal long non-coding RNA networks associated with arteriovenous malformations

Arteriovenous malformations (AVMs) are congenital vascular lesions with a high tendency for aggravation and recurrence after treatment, and their genesis remains enigmatic. In this study, we investigated exosomal long non-coding RNA (lncRNA) and mRNA expression and constructed a competitive endogenous RNA regulatory network in AVMs. Ethics approval was provided, and informed written consent was given prior to the inclusion of all participants. Blood samples were obtained from patients with AVMs and healthy controls at Shanghai Ninth People's Hospital, China, from May to November 2018, and total exosomes were isolated and validated. Differentially expressed exosomal lncRNAs and mRNAs were detected by RNA-seq, analysed by bioinformatic methods and validated by qRT-PCR. A competitive endogenous RNA regulatory network was constructed. The characteristics of the captured extracellular vesicles conformed to the features of exosomes. A total of 117 dysregulated exosomal lncRNAs and 1159 dysregulated exosomal mRNAs were identified in AVMs. qRT-PCR demonstrated that the exosomal lncRNAs MIR4435-1HG, LINC00657, LOC101927854 and SEPT5-GP1BB were upregulated in AVM exosomes. The Gene Ontology (GO) terms haemopoiesis and negative regulation of neuron projection development were significantly enriched in relation to dysregulated exosomal cis lncRNAs. A total of 199 GO terms and 80 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were enriched for the dysregulated exosomal mRNAs. In the exosomal lncRNA-miRNA-mRNA-related ceRNA regulatory network, the top 3 significant modules involved 31 dysregulated exosomal lncRNAs and 114 dysregulated exosomal mRNAs, which were enriched in the Rap 1, Ras, MAPK signalling pathways and platelet activation KEGG pathway. This study comprehensively identified dysregulated exosomal lncRNAs and mRNAs in AVMs, demonstrated the involvement of dysregulated lncRNA and mRNA patterns in AVMs and constructed an exosomal competitive endogenous RNA regulatory network.

Prevalence, risk factors and pregnancy outcomes of women with vascular brain lesions in pregnancy

BACKGROUND

Vascular brain lesions (VBL) occur in up to 4.0% of the general population. With the increasing availability and use of sophisticated imaging techniques, there are more patients being diagnosed with asymptomatic intracranial AVMs and cavernous hemangiomas.

OBJECTIVES

Here we evaluate the association between VBL in pregnancy and the maternal and fetal outcomes.

STUDY DESIGN

The study cohort was identified by isolating all pregnancies from the nationwide inpatient sample (NIS), from the healthcare cost and utilization project (HCUP) over a five-year period. Within this cohort, cases with an arteriovenous malformation (AVM) or cerebral vascular malformations (CVM) were identified and their prevalence was calculated. Baseline demographic characteristics were compared and the odds ratios for various complications and outcomes were calculated.

RESULTS

Amongst 4,012,396 deliveries, VBL were identified in 214 cases: a prevalence of 5.33 cases per 100,000 deliveries. Majority of VBL cases were identified in women between 25 and 35 years of age, but the proportion of women aged 35 and older was greater amongst those patients with VBL. 74% of cases were of Caucasian race and more cases with VBL had a private insurance payer (62.1%). Seizure disorders were present in 63.6% of the cases with VBL. Whilst VBL are not associated with unfavorable obstetrical complications, they are more likely to be delivered by caesarean section (CS) - 79% of VBL cases were delivered by CS compared to 33% of the patients without VBL (OR 7.03 CI 95% 4.98-9.92). Instrumental delivery was performed in 10.3% of the vaginal deliveries for index cases. Index cases were less prone to fetal growth restriction. VBL accounted for 8.4% of 166 cases of intracranial bleeding occurring during the antepartum period within the entire pregnant population.

CONCLUSIONS

Presence of VBL does not appear to carry additional risk to mother or fetus during pregnancy.

Overview of the current concepts in the management of arteriovenous malformations of the brain

Background

There is a lack of consensus in the management of arteriovenous malformations (AVMs) of the brain since ARUBA (A Randomised trial of Unruptured Brain Arteriovenous malformations) trial showed that medical management is superior to interventional therapy in patients with unruptured brain AVMs. The treatment of brain AVM is associated with significant morbidity.

Objectives and methods

A review was done to determine the behaviour of brain AVMs and analyse the risks and benefits of the available treatment options. A search was done in the literature for studies on brain AVMs. Descriptive analysis was also done.

Results

The angiogenic factors such as vascular endothelial growth factor and inflammatory cytokines are involved in the growth of AVMs. Proteinases such as matrix metalloproteinase-9 contribute to the weakening and rupture of the nidus. The risk factors for haemorrhage are prior haemorrhage, deep and infratentorial AVM location, exclusive deep venous drainage and associated aneurysms. The advancements in operating microscope and surgical techniques have facilitated microsurgery. Stereotactic radiosurgery causes progressive vessel obliteration over 2–3 years. Endovascular embolisation can be done prior to microsurgery or radiosurgery and for palliation.

Conclusions

Spetzler-Martin grades I and II have low surgical risks. The AVMs located in the cerebellum, subarachnoid cisterns and pial surfaces of the brainstem can be treated surgically. Radiosurgery is preferable for deep-seated AVMs. A combination of microsurgery, embolisation and radiosurgery is recommended for deep-seated and Spetzler-Martin grade III AVMs. Observation is recommended for grades IV and V.

Cerebral arteriovenous malformations - usability of Spetzler-Martin and Spetzler-Ponce scales in qualification to endovascular embolisation and neurosurgical procedure

Purpose

Arteriovenous malformations (AVMs) are connected with cerebral haemorrhage, seizures, increased intracranial pressure, headaches, mass effect, and ischaemia symptoms. Selection of the best treatment method or even deciding if intervention is required can be difficult.

Material and methods

The study included 50 patients who were diagnosed with cerebral AVMs and treated in our Centre between 2008 and 2014. A total of 111 procedures were performed, including 94 endovascular embolisations and 17 neurosurgical procedures. Medical records and imaging data were reviewed for all patients. All AVMs were measured and assessed, allowing classification in Spetzler-Martin and Spetzler-Ponce scales.

Results

Complete or partial treatment was observed in 88.24% of neurosurgical procedures and in 84.00% of embolisations. Early complication rate was 21.28% for embolisation and 17.65% for neurosurgical procedures, while Glasgow Outcome Scale was 4.89 (σ = 0.38) and 5.0 (σ = 0.00), respectively. According to the Spetzler-Martin scale, cerebral haemorrhages occurred more frequently in grade 1, but no statistical significance was observed. In Spetzler-Ponce class B lower grades in Glasgow Coma Scale (GCS) were noticed (p = 0.02). Lower GCS scores were also correlated with deep location of AVM and with eloquence of adjacent brain. Patients with Spetzler-Martin grade 1 were more frequently qualified for neurosurgical procedures than other patients.

Conclusions

Treating AVMs requires coordination of a multidisciplinary team. Both endovascular embolisation and neurosurgical procedure should be considered as a part of multimodal, frequently multistage treatment. Spetzler-Martin and Spetzler-Ponce scales have an influence on haemorrhage frequency and patients’ clinical condition and should be taken into consideration in selecting the treatment method.

A Retrospective Cohort Analysis of Hemorrhagic Arteriovenous Malformations Treated with Combined Endovascular Embolization and Gamma Knife Stereotactic Radiosurgery

BACKGROUND

The management of brain arteriovenous malformations (AVMs) remains a controversial topic. Given the relatively low incidence, high heterogeneity, and high morbidity and mortality of these lesions, consensus on treatment strategies is an issue of concern to organized neurosurgery. The present retrospective analysis examined and quantified the outcomes of patients with an initial presentation of intracranial hemorrhage from a Spetzler-Martin grade III or IV AVM, later ruled out as surgical candidates.

METHODS

A total of 16 patients (5 females; 11 males) had presented with symptomatic hemorrhage confirmed by non-contrast-enhanced computed tomography and were deemed to not be surgical candidates owing to AVM location and/or architecture. The patients underwent combined endovascular embolization and gamma knife stereotactic radiosurgery (SRS). The modified Rankin scale was used to measure the clinical outcomes, comparing the scores at presentation, gamma knife treatment, and the last known follow-up examination. A radiographic evaluation was used to determine the level of AVM nidus involution after the procedure.

RESULTS

The present study identified 16 patients with ruptured high-grade AVMs of high surgical risk. All the patients had undergone immediate embolization with delayed SRS for treatment of the hemorrhage and nidus of the AVM. A statistically significant proportion of patients showed marked improvement in the modified Rankin scale scores. No subsequent repeat hemorrhage or any associated complications after embolization occurred in any patient.

CONCLUSION

These findings warrant consideration of endovascular embolization with adjuvant SRS as a powerful treatment option for cases with high surgical morbidity due to AVM characteristics.

Neurorehabilitation of saccadic ocular movement in a patient with a homonymous hemianopia postgeniculate caused by an arteriovenous malformation: A Case Report

RATIONALE

Visual therapy, which includes a restorative and compensatory approach, seems to be a viable treatment option for homonymous defects of the visual field in patients with postgeniculate injury of the visual pathway, due to occipital arteriovenous malformation (AVM). Until now, the Mexican population suffering from homonymous hemianopia did not have health services that provided any type of visual therapy for their condition.

PATIENT CONCERNS

A 31-year-old patient, who underwent a surgical procedure for resection of the AVM, was referred with posterior low vision on the left side.

DIAGNOSES

The patient was diagnosed with left homonymous hemianopia.

INTERVENTIONS

Visual neurorehabilitation therapy (NRT), which integrated restorative and compensatory approaches, was administered for 3 hours each week. NRT included fixation, follow-up, search, peripheral vision, and reading.

OUTCOMES

The NRT did not change visual field defects and, retinotopocally, the same campimetric defects remained. However, after training the tracking ocular movements improved to standard values on the ENG, further, the visual search became more organized. The reading reached a level without mistakes, with rhythm and goog intonation. The Beck test demostrated an improvement in depression symptoms. Regarding the daily life activities, the patient reported significant improvements.

LESSONS

Visual NRT can significantly improve eye movements, as well as the quality of life and independence of the patient. This integral approach could be an effective therapeutic option for homonymous defects of the visual field.

Blood-brain barrier-on-a-chip: Microphysiological systems that capture the complexity of the blood-central nervous system interface

The blood-brain barrier is a dynamic and highly organized structure that strictly regulates the molecules allowed to cross the brain vasculature into the central nervous system. The blood-brain barrier pathology has been associated with a number of central nervous system diseases, including vascular malformations, stroke/vascular dementia, Alzheimer's disease, multiple sclerosis, and various neurological tumors including glioblastoma multiforme. There is a compelling need for representative models of this critical interface. Current research relies heavily on animal models (mostly mice) or on two-dimensional (2D) in vitro models, neither of which fully capture the complexities of the human blood-brain barrier. Physiological differences between humans and mice make translation to the clinic problematic, while monolayer cultures cannot capture the inherently three-dimensional (3D) nature of the blood-brain barrier, which includes close association of the abluminal side of the endothelium with astrocyte foot-processes and pericytes. Here we discuss the central nervous system diseases associated with blood-brain barrier pathology, recent advances in the development of novel 3D blood-brain barrier -on-a-chip systems that better mimic the physiological complexity and structure of human blood-brain barrier, and provide an outlook on how these blood-brain barrier-on-a-chip systems can be used for central nervous system disease modeling. Impact statement The field of microphysiological systems is rapidly evolving as new technologies are introduced and our understanding of organ physiology develops. In this review, we focus on Blood-Brain Barrier (BBB) models, with a particular emphasis on how they relate to neurological disorders such as Alzheimer's disease, multiple sclerosis, stroke, cancer, and vascular malformations. We emphasize the importance of capturing the three-dimensional nature of the brain and the unique architecture of the BBB - something that until recently had not been well modeled by in vitro systems. Our hope is that this review will provide a launch pad for new ideas and methodologies that can provide us with truly physiological BBB models capable of yielding new insights into the function of this critical interface.

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.

MicroRNA-137 and microRNA-195* inhibit vasculogenesis in brain arteriovenous malformations

OBJECTIVE

Brain arteriovenous malformations (AVMs) are the most common cause of nontraumatic intracerebral hemorrhage in young adults. The genesis of brain AVM remains enigmatic. We investigated microRNA (miRNA) expression and its contribution to the pathogenesis of brain AVMs.

METHODS

We used a large-scale miRNA analysis of 16 samples including AVMs, hemangioblastoma, and controls to identify a distinct AVM miRNA signature. AVM smooth muscle cells (AVMSMCs) were isolated and identified by flow cytometry and immunohistochemistry, and candidate miRNAs were then tested in these cells. Migration, tube formation, and CCK-8-induced proliferation assays were used to test the effect of the miRNAs on phenotypic properties of AVMSMCs. A quantitative proteomics approach was used to identify protein expression changes in AVMSMCs treated with miRNA mimics.

RESULTS

A distinct AVM miRNA signature comprising a large portion of lowly expressed miRNAs was identified. Among these miRNAs, miR-137 and miR-195* levels were significantly decreased in AVMs and constituent AVMSMCs. Experimentally elevating the level of these microRNAs inhibited AVMSMC migration, tube formation, and survival in vitro and the formation of vascular rings in vivo. Proteomics showed the protein expression signature of AVMSMCs and identified downstream proteins regulated by miR-137 and miR-195* that were key signaling proteins involved in vessel development.

INTERPRETATION

Our results indicate that miR-137 and miR-195* act as vasculogenic suppressors in AVMs by altering phenotypic properties of AVMSMCs, and that the absence of miR-137 and miR-195* expression leads to abnormal vasculogenesis. Ann Neurol 2017;82:371-384.

Neurovascular patterning cues and implications for central and peripheral neurological disease

The highly branched nervous and vascular systems run along parallel trajectories throughout the human body. This stereotyped pattern of branching shared by the nervous and vascular systems stems from a common reliance on specific cues critical to both neurogenesis and angiogenesis. Continually emerging evidence supports the notion of later-evolving vascular networks co-opting neural molecular mechanisms to ensure close proximity and adequate delivery of oxygen and nutrients to nervous tissue. As our understanding of these biologic pathways and their phenotypic manifestations continues to advance, identification of where pathways go awry will provide critical insight into central and peripheral nervous system pathology.

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.

Genetic and epigenetic mechanisms in the development of arteriovenous malformations in the brain

Vascular malformations are developmental congenital abnormalities of the vascular system which may involve any segment of the vascular tree such as capillaries, veins, arteries, or lymphatics. Arteriovenous malformations (AVMs) are congenital vascular lesions, initially described as “erectile tumors,” characterized by atypical aggregation of dilated arteries and veins. They may occur in any part of the body, including the brain, heart, liver, and skin. Severe clinical manifestations occur only in the brain. There is absence of normal vascular structure at the subarteriolar level and dearth of capillary bed resulting in aberrant arteriovenous shunting. The causative factor and pathogenic mechanisms of AVMs are unknown. Importantly, no marker proteins have been identified for AVM. AVM is a high flow vascular malformation and is considered to develop because of variability in the hemodynamic forces of blood flow. Altered local hemodynamics in the blood vessels can affect cellular metabolism and may trigger epigenetic factors of the endothelial cell. The genes that are recognized to be associated with AVM might be modulated by various epigenetic factors. We propose that AVMs result from a series of changes in the DNA methylation and histone modifications in the genes connected to vascular development. Aberrant epigenetic modifications in the genome of endothelial cells may drive the artery or vein to an aberrant phenotype. This review focuses on the molecular pathways of arterial and venous development and discusses the role of hemodynamic forces in the development of AVM and possible link between hemodynamic forces and epigenetic mechanisms in the pathogenesis of AVM.

Surgical Management of Giant Intracranial Arteriovenous Malformations: A Single Center Experience over 32 years

OBJECTIVE

Treatment of giant intracranial arteriovenous malformations (gAVMs) is a formidable challenge for neurosurgeons and carries significant morbidity and mortality rates for patients compared with smaller AVMs. In this study, we reviewed the treatments, angiographic results, and clinical outcomes in 64 patients with gAVMs who were treated at Henry Ford Hospital between 1980 and 2012.

METHODS

The arteriovenous malformation (AVM) database at our institution was queried for patients with gAVMs (≥ 6 cm) and data regarding patient demographics, presentation, AVM angioarchitecture, and treatments were collected. Functional outcomes as well as complications were analyzed.

RESULTS

Of the 64 patients, 33 (51.6%) were female and 31 (48.4%) were male, with an average age of 45.7 years (SD ± 15.5). The most common symptoms on presentation were headaches (50%), seizures (50%), and hemorrhage (41%). The mean AVM size was 6.65 cm (range, 6-9 cm). Only 6 AVMs (9.4%) were located in the posterior fossa. The most common Spetzler-Martin grade was V, seen in 64% of patients. Of the 64 patients, 42 (66%) underwent surgical excision, 10 (15.5%) declined any treatment, 8 (12.5%) were deemed inoperable and followed conservatively, 2 (3%) had stand-alone embolization, 1 (1.5%) had embolization before stereotactic radiosurgery, and 1 (1.5%) received stereotactic radiosurgery only. Complete obliteration was achieved in 90% of the surgical patients. Mortality rate was 19% in the surgical cohort compared with 22% in the observation cohort (P = 0.770).

CONCLUSIONS

Treatment of gAVMs carries significant morbidity and mortality; however, good outcomes are attainable with a multimodal treatment approach in carefully selected patients.

Open repair, endovascular repair, and conservative management of true splenic artery aneurysms

OBJECTIVE

True splenic artery aneurysms (SAAs) are a rare but potentially fatal pathology. For many years, open repair (OPEN) and conservative management (CONS) were the treatments of choice, but throughout the last decade endovascular repair (EV) has become increasingly used. The purpose of the present study was to perform a systematic review and meta-analysis evaluating the outcomes of the three major treatment modalities (OPEN, EV, and CONS) for the management of SAAs.

METHODS

A systematic review of all studies describing the outcomes of SAAs treated with OPEN, EV, or CONS was performed using seven large medical databases. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed to ensure a high-quality review. All articles were subject to critical appraisal for relevance, validity, and availability of data regarding characteristics and outcomes. All data were systematically pooled, and meta-analyses were performed on several outcomes, including early and late mortality, complications, and number of reinterventions.

RESULTS

Original data of 1321 patients with true SAAs were identified in 47 articles. OPEN contained 511 patients (38.7%) in 31 articles, followed by 425 patients (32.2%) in CONS in 16 articles and 385 patients (29.1%) in EV in 33 articles. The CONS group had fewer symptomatic patients (9.5% vs 28.7% in OPEN and 28.8% in EV; P < .001) and fewer ruptured aneurysms (0.2% vs 18.4% in OPEN and 8.8% in EV; P < .001), but no significant differences were found in existing comorbidities. CONS patients were usually older and had smaller-sized aneurysms than patients in the OPEN and EV groups. The only identified difference in baseline characteristics between OPEN and EV was the number of ruptured aneurysms (18.4% vs 8.8%; P < .001). OPEN had a higher 30-day mortality than EV (5.1% vs 0.6%; P < .001), whereas minor complications occurred in a larger number of the EV patients. EV required more reinterventions per year (3.2%) compared with OPEN (0.5%) and CONS (1.2%; P < .001). The late mortality rate was higher in patients treated with CONS (4.9% vs 2.1% in OPEN and 1.4% in EV; P = .04).

CONCLUSIONS

EV of SAA has better short-term results compared with OPEN, including significantly lower perioperative mortality. OPEN is associated with fewer late complications and fewer reinterventions during follow-up. Patients treated with CONS showed a higher late mortality rate. Ruptured SAAs are predictors of a significantly higher perioperative mortality compared with nonruptured SAAs in the OPEN and EV groups.