Review of de novo cerebral arteriovenous malformation: haemorrhage risk, treatment approaches and outcomes

Late chronic local inflammation, synaptic alterations, vascular remodeling and arteriovenous malformations in the brains of male rats exposed to repetitive low-level blast overpressures

In the course of military operations in modern war theaters, blast exposures are associated with the development of a variety of mental health disorders associated with a post-traumatic stress disorder-related features, including anxiety, impulsivity, insomnia, suicidality, depression, and cognitive decline. Several lines of evidence indicate that acute and chronic cerebral vascular alterations are involved in the development of these blast-induced neuropsychiatric changes. In the present study, we investigated late occurring neuropathological events associated with cerebrovascular alterations in a rat model of repetitive low-level blast-exposures (3 × 74.5 kPa). The observed events included hippocampal hypoperfusion associated with late-onset inflammation, vascular extracellular matrix degeneration, synaptic structural changes and neuronal loss. We also demonstrate that arteriovenous malformations in exposed animals are a direct consequence of blast-induced tissue tears. Overall, our results further identify the cerebral vasculature as a main target for blast-induced damage and support the urgent need to develop early therapeutic approaches for the prevention of blast-induced late-onset neurovascular degenerative processes.

Intracranial arteriovenous malformation (AVM) or meningothelial meningioma (MM)? Outlining the similarities and differences on imaging studies for an accurate diagnosis, case report

INTRODUCTION AND IMPORTANCE

AVM and MM represent neurosurgical challenges, not only when involving eloquent brain, but also by posing a significant intraoperative haemorrhagic risk. It is a challenge in itself to establish a proper differential diagnosis between the two lesions, especially since they require distinct interventional plan of action. We present the case of a patient initially diagnosed by specialists with an intracranial AVM, which was revealed intraoperatively to be in fact an MM.

CASE PRESENTATION

A 29-years patient, transferred to our department by urgency. The patient symptoms started two weeks prior admission with severe headache and vomiting. A cerebral computer tomographic angiography (CTA) was performed and interpreted by radiologists, as a large left frontal AVM.

CLINICAL DISCUSSION

Upon through review the majority of surgical team believed the mass to be AVM. However, during surgery it turned out to be Meningioma. The patient underwent a left pterional craniotomy with removal of the tumour, classified as Simpson grade II. The pathological exam confirmed the lesion to be an MM.

CONCLUSIONS

Acquiring neuro-radiological expertise is vital for the neurosurgeon, as well as fast ability for adjusting the initial action plan with the intraoperative discoveries. An experienced eye can benefit the patient by obtain a correct diagnosis in most difficult cases.

Dural arteriovenous fistula causing reversible cognitive impairment

A previously independent 82-year-old woman presented with 5 months of worsening confusion, mobility and cognitive decline, with deficits in orientation, language and executive function. A cerebral dural arteriovenous fistula was identified and successfully embolised, after which her cognitive ability and independence dramatically improved. Although rare, a dural arteriovenous fistula may mimic a rapidly progressive dementia, but its early recognition and treatment can completely reverse the dementia.

De novo brain AVM following radiotherapy for cerebral cavernous malformation in a child: A 15-year clinical course

Multiple de novo brain arteriovenous malformations (bAVM) have been reported in the literature, raising questions about the contended purely congenital nature of these lesions. We present the 15-year course of a pediatric patient, who initially presented at age 5 with a thalamic cavernous malformation and was treated with radiosurgery, and then subsequently developed a thalamic de novo bAVM immediately adjacent to the initial lesion location, discovered 2 years later. Treatment of the bAVM entailed two transarterial embolizations and one radiosurgery session which ultimately led to complete angiographic resolution. Finally, this patient's course was complicated by intraparenchymal hemorrhage and acute obstructive hydrocephalus, and further imaging revealed two newly formed cavernous malformations, also associated with the initial lesion's location, that have remained stable since their formation. This case likely represents the second-hit model for the formation of vascular malformations, as sparsely supported by the current literature. According to this, genetically aberrant, yet quiescent, brain areas might promote the de novo formation of vascular malformations after brain injury, including radiation.

Sudden death caused by ruptured brain arteriovenous malformation in an adolescent with autism spectrum disorder

Brain arteriovenous malformations (bAVMs) are infrequent disorders in the pediatric population. The rupture of a bAVM is a clinical emergency often followed by death. Autism spectrum disorder shares a number of symptoms with AVM malformation; this may impede antemortem diagnosis. An 11-year-old boy with autism spectrum disorder (ASD) without other medical history died suddenly. Initially, choking on a peanut butter sandwich was suspected; autopsy did not demonstrate aspiration, but identified a ruptured right cerebellar AVM, with the characteristic tortuous vessels. The histology on the lesion confirmed the presence of arterialized veins and showed gliotic tissue and hemosiderin-laden macrophages, consistent with prior bleeding. BAVM pathogenesis is unknown; congenital disease may have several mechanisms including genetic predisposition and familial risk factors; development de novo may occur after hemorrhagic intracranial events such as surgical intervention and head trauma. ASD may present with overlapping symptoms of bAVM and may also interfere with expressing subtle neurologic symptoms to caretakers. ASD and AVM are rarely reported in association.

An acquired cerebral arteriovenous malformation after brain abscess treatment: case report and a review of the literature

A cerebral arteriovenous malformation (AVM) is a congenital and static disease. However, there are increasing reports of acquired AVMs. The pathophysiology of an acquired AVM has not been fully elucidated but the suggested pathophysiology is a combination of genetic abnormalities and inflammatory cytokines caused by previous brain insults. We report a patient who developed an acquired AVM after the treatment for a brain abscess. She underwent Gamma Knife surgery to treat the acquired AVM. It is necessary to understand the characteristics of acquired AVMs and to further research acquired AVMs.

Homocysteine Level and Risk of Hemorrhage in Brain Arteriovenous Malformations

Objective

We aimed to investigate the risk factors associated with hemorrhage and clarify the relation of homocysteine (Hcy) with brain arteriovenous malformations (bAVMs).

Method

We retrospectively reviewed bAVM patients from Beijing Tiantan Hospital between January 2019 and December 2019. Clinical and laboratory variables were analyzed in enrolled patients with bAVMs. Potential predictors associated with hemorrhage were evaluated by logistic regression analysis.

Results

A total of 143 bAVM patients were identified in the study, including 69 unruptured and 74 ruptured cases. Patients with hemorrhage were less likely to have hyperhomocysteinemia (P = 0.023). Logistic regression analysis showed that increased maximum diameter of bAVM lesions (odds ratio (OR) 0.634, 95% confidence intervals (CI) 0.479-0.839; P = 0.001) and serum Hcy level (OR 0.956, 95% CI 0.920-0.993; P = 0.021) were associated with lower risk of hemorrhage in bAVMs.

Conclusion

The present study provided evidence regarding the association between serum Hcy and hemorrhage in patients with bAVMs. Higher Hcy level was correlated with a lower risk of rupture. Detection of factors for subsequent hemorrhage is necessary to develop therapeutic strategies for bAVMs preferably.

Metachronous spinal pial arteriovenous fistulas: case report

Spinal pial arteriovenous fistulas (spAVFs) are believed to be congenital lesions, and the development of a de novo spAVF has not been previously described. A 49-year-old female with a childhood history of vascular malformation-induced right lower-extremity hypertrophy presented in 2004 with progressive pain in her right posterior thigh and outer foot. Workup revealed 3 separate type IV spAVFs, which were treated by combined embolization and resection, with final conventional angiography showing no residual spinal vascular lesion in 2005. Ten years later, the patient returned with new right lower-extremity weakness, perineal pain, and left plantar foot numbness. Repeat spinal angiography demonstrated 2 de novo intertwined conus medullaris spAVFs.

Cerebral Arteriovenous Malformations as Acquired Lesions: Case Reports and Review of the Literature

Cerebral arteriovenous malformations (AVMs) are generally attributed to congenital lesions that arise from aberrant vasculogenesis between the fourth and eighth weeks of embryonic life. However, this dogma has been challenged by several recent observations, one of which is de novo formation of AVMs. Forty cases of de novo AVMs were published between 2000 and 2019, all of which involved a history of intracranial insult, such as vascular abnormalities or nonvascular conditions, prior to AVM diagnosis. We hereby present two unique operative cases of ruptured de novo AVMs in older adult patients. Case 1 is novel in the sense that the patient did not experience any kind of environmental trigger ("second hit") such as a previous intracranial insult, while Case 2 serves as the second report of a de novo AVM patient with a medical history of Bell's palsy. Although the exact mechanisms of AVM formation remain to be elucidated, it is likely to be a multifactorial process related to environmental and hemodynamic factors.

De novo intracranial arteriovenous malformation development after endovascular treatment for a pial arteriovenous fistula in capillary malformation-arteriovenous malformation syndrome

Capillary malformation-arteriovenous malformation (CM-AVM) syndrome is a newly described entity characterized by autosomal dominantly inherited multifocal capillary malformations caused by RASA1 mutations (CM-AVM1) or EPHB4 mutations (CM-AVM2). Concurrent high-flow vascular anomalies in the brain are often present in the form of intracranial AVM or arteriovenous fistula (AVF). These high-flow lesions are often identified at or soon after birth because of the characteristic unique capillary malformations or a systemic disorder due to a high-flow shunt, such as respiratory distress or heart failure. However, de novo intracranial AVMs have not been reported in patients with CM-AVM syndrome. Herein, we report the case of a six-year-old boy with CM-AVM1 who had been treated for an intracranial pial arteriovenous fistula approximately five years previously, in whom a de novo intracranial AVM was identified on a follow-up angiographic study. To the best of our knowledge, this report is the first to document a de novo intracranial AVM in a patient with CM-AVM. We recommend careful neuroimaging follow-up even if initial neuroimaging screening is negative because of the risk of de novo AVM development.

De novo thalamic arteriovenous malformation in a boy with a brainstem cavernous malformation

Brain arteriovenous malformations (bAVMs) have long been considered to be congenital, developing between the third and eighth weeks of embryogenesis. However, cases reporting their de novo formation suggest that these lesions can develop after birth and have challenged this concept. We present a case of a 6-year-old boy with a history of a brainstem cavernous malformation diagnosed after birth who later developed a de novo bAVM. The de novo occurrence of this bAVM distant to the site of the cavernous malformation and a prior negative catheter angiography contributes to the uncertainty of the dynamics and pathophysiology of bAVMs.

Arteriovenous Malformations: Congenital or Acquired Lesions?

OBJECTIVE

Arteriovenous malformations (AVMs) were believed to be congenital. However, an increasing number of de novo AVM cases have questioned this doctrine.

METHODS

A consensus meeting of international experts attempted to establish a consensus on the nature of these relatively rare but challenging vascular lesions. In addition, an extensive search of the subject was performed using the PubMed medical database.

RESULTS

All participants agreed that genetic factors may play a role in the pathogenesis of AVMs. All but 1 participant believed that an underlying genetic predisposition may be detected later on in a patient's life, whereas genetic variations may contribute to sporadic AVM formation. The presence of genetic variations alone may not be enough for an AVM formation. A second hit is probably required. This consensus opinion is also supported by our literature search.

CONCLUSIONS

We discuss the literature on the genetics of AVMs and compare it with the consensus meeting outcomes. The congenital or noncongenital character of intracranial AVMs has an impact on the understanding their biological behavior, as well as their efficient short-term and long-term management.

Spontaneous appearance of de novo intracranial arteriovenous malformation in hepatic cirrhosis

BACKGROUND

Intracranial arteriovenous malformations (AVMs) are rare lesions that can be congenital or acquired in early childhood, with fatal outcome in approximately 30% of cases. De novo formation during adulthood without established predisposing vascular pathology or previous brain insult is even less frequent.

CASE DESCRIPTION

We present a case of de novo brain AVM in an alcoholic Child-B cirrhosis setting. Thirty previously reported cases presented de novo AVM in patients of all ages that had another previous brain pathology or insult, such as AVM resection. Seventeen of those cases occurred in adult patients, with only 2 showing no significant predisposing factor. The present pathophysiological review covers and completes Mullan's hemodynamic "two-hit" model, associating probable thrombotic predisposition to AVM with brain insult triggering a later stage based on angiogenic stimuli.

CONCLUSIONS

This case report and literature review renews previously discussed hemodynamic theories and contributes to a fuller understanding of the pathogenesis and progression of AVM. We postulate a causal link between hepatopathy and de novo AVM, which should be strengthened and interpreted based on recent genetic data and future prospective studies.

Transarterial Onyx Embolization of Residual Arteriovenous Malformation After Surgical Resection

OBJECTIVE

We sought to report transarterial Onyx embolization of residual brain arteriovenous malformation (AVM) after surgical resection.

METHODS

From January 2017 to January 2019, 7 patients with residual AVM after surgery were treated by transarterial Onyx embolization. Demographics, angioarchitectural characteristics, complications, and results were retrospectively reviewed.

RESULTS

All patients presented initially with a ruptured AVM. Residual AVM was found on control angiograms within 1 month after surgery. All residual AVMs were cured by transarterial Onyx embolization. One patients experienced feeding artery perforation without adding new neurologic deficits.

CONCLUSIONS

Complete obliteration of residual AVMs can be obtained by salvage transarterial Onyx embolization.