Natural history of brain arteriovenous malformations: a systematic review

Involvement of Microglia in the Pathophysiology of Intracranial Aneurysms and Vascular Malformations-A Short Overview

Aneurysms and vascular malformations of the brain represent an important source of intracranial hemorrhage and subsequent mortality and morbidity. We are only beginning to discern the involvement of microglia, the resident immune cell of the central nervous system, in these pathologies and their outcomes. Recent evidence suggests that activated proinflammatory microglia are implicated in the expansion of brain injury following subarachnoid hemorrhage (SAH) in both the acute and chronic phases, being also a main actor in vasospasm, considerably the most severe complication of SAH. On the other hand, anti-inflammatory microglia may be involved in the resolution of cerebral injury and hemorrhage. These immune cells have also been observed in high numbers in brain arteriovenous malformations (bAVM) and cerebral cavernomas (CCM), although their roles in these lesions are currently incompletely ascertained. The following review aims to shed a light on the most significant findings related to microglia and their roles in intracranial aneurysms and vascular malformations, as well as possibly establish the course for future research.

An Insight into the microRNAs Associated with Arteriovenous and Cavernous Malformations of the Brain

Background: Brain arteriovenous malformations (BAVMs) and cerebral cavernous malformations (CCMs) are rare developmental anomalies of the intracranial vasculature, with an irregular tendency to rupture, and as of yet incompletely deciphered pathophysiology. Because of their variety in location, morphology, and size, as well as unpredictable natural history, they represent a management challenge. MicroRNAs (miRNAs) are strands of non-coding RNA of around 20 nucleotides that are able to modulate the expression of target genes by binding completely or partially to their respective complementary sequences. Recent breakthroughs have been made on elucidating their contribution to BAVM and CCM occurrence, growth, and evolution; however, there are still countless gaps in our understanding of the mechanisms involved. Methods: We have searched the Medline (PubMed; PubMed Central) database for pertinent articles on miRNAs and their putative implications in BAVMs and CCMs. To this purpose, we employed various permutations of the terms and idioms: ‘arteriovenous malformation’, ‘AVM’, and ‘BAVM’, or ‘cavernous malformation’, ‘cavernoma’, and ‘cavernous angioma’ on the one hand; and ‘microRNA’, ‘miRNA’, and ‘miR’ on the other. Using cross-reference search; we then investigated additional articles concerning the individual miRNAs identified in other cerebral diseases. Results: Seven miRNAs were discovered to play a role in BAVMs, three of which were downregulated (miR-18a, miR-137, and miR-195*) and four upregulated (miR-7-5p, miR-199a-5p, miR-200b-3p, and let-7b-3p). Similarly, eight miRNAs were identified in CCM in humans and experimental animal models, two being upregulated (miR-27a and mmu-miR-3472a), and six downregulated (miR-125a, miR-361-5p, miR-370-3p, miR-181a-2-3p, miR-95-3p, and let-7b-3p). Conclusions: The following literature review endeavored to address the recent discoveries related to the various implications of miRNAs in the formation and growth of BAVMs and CCMs. Additionally, by presenting other cerebral pathologies correlated with these miRNAs, it aimed to emphasize the potential directions of upcoming research and biological therapies.

Efficacy and Safety of Combined Endovascular Embolization and Stereotactic Radiosurgery for Patients with Intracranial Arteriovenous Malformations: A Systematic Review and Meta-Analysis

Whether the use of endovascular embolization could provide additional benefits in patients treated with stereotactic radiosurgery (SRS) for intracranial arteriovenous malformations (IAVMs) remains controversial. The current meta-analysis was conducted to assess the efficacy and safety of SRS with and without prior endovascular embolization in patients with IAVMs. The electronic databases of PubMed, EmBase, and Cochrane Library were systematically searched for eligible studies published from inception to August 12, 2020. The pooled results for obliteration rate, rehemorrhage rate, and permanent neurological deficits were calculated by odds ratios (ORs) with 95% confidence intervals (CIs) using the random-effects model. The sensitivity analysis, subgroup analysis, and publication bias for investigated outcomes were also evaluated. Nineteen studies (two prospective and 17 retrospective studies) involving a total of 3,454 patients with IAVMs were selected for the final meta-analysis. We noted that prior embolization and SRS were associated with a lower obliteration rate compared with SRS alone (OR, 0.57; 95% CI, 0.44–0.74; P < 0.001). However, prior embolization and SRS were not associated with the risk of rehemorrhage (OR, 1.05; 95% CI, 0.81–1.34; P = 0.729) and permanent neurological deficits (OR, 0.80; 95% CI, 0.48–1.33; P = 0.385) compared with SRS alone. The sensitivity analysis suggested that prior embolization might reduce the risk of permanent neurological deficits in patients with IAVMs treated with SRS. The treatment effects of prior embolization in patients with IAVMs could be affected by nidus volume, margin dose, intervention, and follow-up duration. This study found that prior embolization was associated with a reduced risk of obliteration in patients with IAVMs treated with SRS. Moreover, prior embolization might reduce the risk of permanent neurological deficits in patients with IAVMs.

Incidental Massive Hydrocephalus Associated With an Unruptured Choroid Plexus Arteriovenous Malformation and Complete Agenesis of the Corpus Callosum Found in an Adult at Autopsy

Undiagnosed significant hydrocephalus is an uncommon finding at forensic autopsy as many cases present in life with complex neurological symptoms. We present a case of a 46-year-old man with no neurological deficits or history of head trauma that was incidentally found to have a massive hydrocephalus at autopsy. This was found to be associated with an unruptured arteriovenous malformation completely confined to the choroid plexus as well as complete agenesis of the corpus callosum. The arteriovenous malformation was found to form a calcified obstruction at the foramen of Monro analogous to a mass lesion, such as a colloid cyst of the third ventricle. The association of this malformation and agenesis of the corpus callosum has never been described. Histologic examination of the brain confirmed significant loss of white matter tracts and thinning of the cortical ribbon due to pressure atrophy of the ependymal lining without significant gliosis, cortical dysplasia, or evidence of other developmental malformations. Autopsy is a vital tool in the evaluation of such rare cases, enhances epidemiologic data, and increases the understanding of these pathophysiological associations.

Brain Arteriovenous Malformations: The Role of Imaging in Treatment Planning and Monitoring Response

Brain arteriovenous malformations (AVMs) are characterized by shunting between pial arteries and cortical or deep veins, with the presence of an intervening nidus of tortuous blood vessels. These lesions present a therapeutic challenge, because their natural history entails a risk of intracranial hemorrhage, but treatment may cause significant morbidity. In this article, imaging features of AVMs on MR imaging and catheter angiography are reviewed to stratify the risk of hemorrhage and guide appropriate management. The angioarchitecture of AVMs may evolve over time, spontaneously or in response to treatment, necessitating ongoing imaging surveillance.

Multimodal Treatment of Pediatric Ruptured Brain Arteriovenous Malformations: A Single-Center Study

Bleeding from ruptured brain arteriovenous malformations (bAVMs) represents the most prevalent cause of pediatric intracranial hemorrhage, being also the most common initial bAVM manifestation. A therapeutic approach in these patients should aim at preventing rebleeding and associated significant morbidity and mortality. The purpose of this study was to determine the clinical outcomes of pediatric patients who initially presented at our institution with ruptured bAVMs and to review our experience with a multimodality approach in the management of pediatric ruptured bAVMs. We retrospectively reviewed pediatric patients’ medical records with ruptured bAVMs who underwent interventional treatment (microsurgery, embolization, or radiosurgery; solely or in combination) at our institution between 2011 and 2020. We identified 22 patients. There was no intraoperative and postoperative intervention-related mortality. Neither procedure-related complications nor rebleeding were observed after interventional treatment. Modified Rankin Scale (mRS) assessment at discharge revealed 19 patients (86.4%) with favorable outcomes (mRS 0–2) and 3 patients (13.6%) classified as disabled (mRS 3). Microsurgery ensured the complete obliteration in all patients whose postoperative digital subtraction angiography (DSA) was available. Management of high-grade bAVMs with radiosurgery or embolization can provide satisfactory outcomes without a high disability risk.

'De Novo' Brain AVMs-Hypotheses for Development and a Systematic Review of Reported Cases

Background and Objectives: Brain arteriovenous malformations AVMs have been consistently regarded as congenital malformations of the cerebral vasculature. However, recent case reports describing "de novo AVMs" have sparked a growing debate on the nature of these lesions. Materials and Methods: We have performed a systematic review of the literature concerning de novo AVMs utilizing the PubMed and Google Academic databases. Termes used in the search were "AVM," "arteriovenous," "de novo," and "acquired," in all possible combinations. Results: 53 articles including a total of 58 patients harboring allegedly acquired AVMs were identified by researching the literature. Of these, 32 were male (55.17%), and 25 were female (43.10%). Mean age at de novo AVM diagnosis was 27.833 years (standard deviation (SD) of 21.215 years and a 95% confidence interval (CI) of 22.3 to 33.3). Most de novo AVMs were managed via microsurgical resection (20 out of 58, 34.48%), followed by radiosurgery and conservative treatment for 11 patients (18.97%) each, endovascular embolization combined with resection for five patients (8.62%), and embolization alone for three (5.17%), the remaining eight cases (13.79%) having an unspecified therapy. Conclusions: Increasing evidence suggests that some of the AVMs discovered develop some time after birth. We are still a long way from finally elucidating their true nature, though there is reason to believe that they can also appear after birth. Thus, we reason that the de novo AVMs are the result of a 'second hit' of a variable type, such as a previous intracranial hemorrhage or vascular pathology. The congenital or acquired characteristic of AVMs may have a tremendous impact on prognosis, risk of hemorrhage, and short and long-term management.

Systematic review of brain arteriovenous malformation grading systems evaluating microsurgical treatment recommendation

When evaluating brain arteriovenous malformations (bAVMs) for microsurgical resection, the natural history of bAVM rupture must be balanced against the perioperative risks. It is therefore adamant to have a reliable surgical grading system, balancing these important factors. This study systematically reviews the literature in order to identify and assess the quality of grading systems with regard to microsurgical bAVM treatment. A systematic literature review was performed to provide an overview of all available bAVM grading systems relevant for microsurgical treatment evaluation and to assess the most comprehensive grading system specifically for each subgroup of bAVM (i.e., unruptured, ruptured, and posterior fossa). Screening of 865 papers revealed thirteen grading systems for bAVM microsurgical risk stratification. Among them, two systems were specifically developed for ruptured bAVM and one specifically for posterior fossa bAVM. With one system being fundamentally different for supratentorial bAVM, the remaining nine systems used the same parameters: “size,” “eloquence,” “venous drainage,” “arterial feeders,” “age,” “nidus compactness,” and “hemorrhagic presentation”. This study provides a comprehensive overview of all available bAVM grading systems relevant for surgical risk stratification. Furthermore, in the absence of a universal system appropriate to score all bAVMs, a workflow for selection of the best applicable scoring system in accordance with bAVM subgroups is presented.

Radiosurgery for unruptured brain arteriovenous malformations in the pre-ARUBA era: long-term obliteration rate, risk of hemorrhage and functional outcomes

The management of non-hemorrhagic arteriovenous malformations (AVMs) remains a subject of debate, even more since the ARUBA trial. Here, we report the obliteration rate, the risk of hemorrhage and the functional outcomes after Gamma Knife radiosurgery (GKRS) as first-line treatment for non-hemorrhagic AVMs treated before the ARUBA publication, in a reference university center with multimodal AVM treatments available. We retrospectively analyzed data from a continuous series of 172 patients harboring unruptured AVMs treated by GKRS as first-line treatment in our Lille University Hospital, France, between April 2004 and December 2013. The primary outcome was obliteration rate. Secondary outcomes were the hemorrhage rate, the modified Rankin Scale (mRS), morbidity and epilepsy control at last follow-up. The minimal follow-up period was of 3 years. Median age at presentation was 40 years (IQR 28; 51). Median follow-up was 8.8 years (IQR 6.8; 11.3). Median target volume was 1.9 cm³ (IQR 0.8–3.3 cm³), median Spetzler-Martin grade: 2 (IQR 1–2), median Pollock-Flickinger score: 1.07 (IQR 0.82–2.94), median Virginia score: 1 (IQR 1–2). Median treatment dose was 24 Gy at 50% isodose line. Twenty-three patients underwent a second GKRS after a median time of 58 months after first GKRS. The overall obliteration rate was of 76%, based primarily on cerebral angiography and/or rarely only upon MRI. Hemorrhage during the post-treatment follow-up was reported in 18 (10%) patients (annual risk of 1.1%). Transient post-GKRS morbidity was reported in 14 cases (8%) and persistent neurological deficit in 8 (4.6%) of patients. At last follow-up, 86% of patients had a mRS ≤ 1. Concerning patients with pretherapeutic epilepsy, 84.6% of them were seizure-free at last follow-up. GKRS as first-line therapeutic option for unruptured cerebral AVMs achieves high obliteration rates (76%) while maintaining a high-level patient’s autonomy. All hemorrhagic events occurred during the first 4 years after the initial GKRS. In cases with epilepsy, there was 84.6% seizure free at last follow-up. Permanent morbidity was reported in only 4.6%.

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.

Radiotherapy of non-tumoral refractory neurological pathologies

Intracranial radiotherapy has been improved, primarily because of the development of stereotactic approaches. While intracranial stereotactic body radiotherapy is mainly indicated for treatment of benign or malignant tumors, this procedure is also effective in the management of other neurological pathologies; it is delivered using GammaKnife® and linear accelerators. Thus, brain arteriovenous malformations in patients who are likely to experience permanent neurological sequelae can be managed by single session intracranial stereotactic body radiotherapy, or radiosurgery, in specific situations, with an advantageous benefit/risk ratio. Radiosurgery can be recommended for patients with disabling symptoms, which are poorly controlled by medication, such as trigeminal neuralgia, and tremors, whether they are essential or secondary to Parkinson's disease. This literature review aims at defining the place of intracranial stereotactic body radiotherapy in the management of patients suffering from non-tumoral refractory neurological pathologies. It is clear that the multidisciplinary collaboration of experienced teams from Neurosurgery, Neurology, Neuroradiology, Radiation Oncology and Medical Physics is needed for the procedures using high precision radiotherapy techniques, which deliver high doses to locations near functional brain areas.

Is smoking a risk factor for bleeding in adult men with cerebral arteriovenous malformations? A single-center regression study from China

OBJECTIVE

To assess whether smoking increases the risk of bleeding in patients with cerebral arteriovenous malformations (CAVM).

MATERIAL AND METHODS

According to our research plan, 385 CAVM patients admitted to Beijing Tiantan Hospital from December 2015 to January 2018 were included in this study, including 210 bleeding patients and 175 non-bleeding patients. We divided patients into three subgroups of current smokers, ex-smokers (those who quit smoking for one year or more) and non-smokers. The relationship between smoking and the risk of CAVM rupture was assessed by univariate and multivariate regression analysis.

RESULTS

Multivariate regression analysis showed that there was a statistically significant difference between current smoker and non-smoker (OR = 1.87, p = 0.019). Among the covariates of the multivariate regression analysis, the location, combined with blood flow-related intracranial aneurysms and size were related to the risk of CAVM bleeding.

CONCLUSION

Current smoking may increase the risk of CAVM bleeding; however, there was no significant correlation between ex-smoking and CAVM bleeding.

Deciphering the vascular labyrinth: role of microRNAs and candidate gene SNPs in brain AVM development - literature review

Background: Brain arteriovenous malformations (AVMs) are a relatively infrequent vascular pathology of unknown etiology that, despite their rarity, cause the highest number of hemorrhagic strokes under the age of 30 years. They pose a challenge to all forms of treatment due to their variable morphology, location, size, and, last but not least, evolving nature. MicroRNAs (miRNAs) are non-coding RNA strands that may suppress the expression of target genes by binding completely or partially to their complementary sequences. Single nucleotide polymorphisms (SNPs), as the name implies, are variations in a single nucleotide in the DNA, usually found in the non-coding segments. Although the majority of SNPs are harmless, some located in the proximity of candidate genes may result in altered expression or function of these genes and cause diseases or affect how different pathologies react to treatment. The roles miRNAs and certain SNPs play in the development and growth of AVMs are currently uncertain, yet progress in deciphering the minutiae of this pathology is already visible. Methods and Results: We performed an electronic Medline (PubMed, PubMed Central) and Google Academic exploration using permutations of the terms: "arteriovenous malformations," "single nucleotide polymorphisms," "microRNA," "non-coding RNA," and "genetic mutations." The findings were then divided into two categories, namely the miRNAs and the candidate gene SNPs associated with AVMs respectively. 6 miRNAs and 12 candidate gene SNPs were identified and discussed. Conclusions: The following literature review focuses on the discoveries made in ascertaining the different implications of miRNAs and candidate gene SNPs in the formation and evolution of brain AVMs, as well as highlighting the possible directions of future research and biological treatment. Abbreviations: ACVRL1/ALK1: activin receptor-like kinase 1; Akt: protein kinase B; ANGPTL4: angiopoietin-like 4; ANRIL: antisense noncoding RNA in the INK4 locus; AVM: arteriovenous malformation; AVM-BEC: arteriovenous malformation brain endothelial cell; BRCA1: breast cancer type 1 susceptibility protein; CCS: case-control study; CDKN2A/B: cyclin-dependent kinase inhibitor 2A/B; CLTC: clathrin heavy chain; DNA: deoxyribonucleic acid; ERK: extracellular signal-regulated kinase; GPR124: probable G-protein coupled receptor 124; GWAS: genome-wide association study; HHT: hereditary hemorrhagic telangiectasia; HIF1A: hypoxia-inducible factor 1A; IA: intracranial aneurysm; ICH: intracranial hemorrhage; Id-1: inhibitor of DNA-binding protein A; IL-17: interleukin 17; MAP4K3: mitogen-activated protein kinase kinase kinase kinase 3; miRNA: microRNA; MMP: matrix metalloproteinase; NFkB: nuclear factor kappa-light-chain of activated B cells; NOTCH: neurogenic locus notch homolog; p38MAPK: p38 mitogen-activated protein kinase; PI3K: phosphoinositide 3-kinase; RBBP8: retinoblastoma-binding protein 8; RNA: ribonucleic acid; SNAI1: Snail Family Transcriptional Repressor 1; SNP: single nucleotide polymorphism; SOX-17: SRY-related HMG-box; TGF-β: transformation growth factor β; TGFR: transformation growth factor receptor; TIMP-4, tissue inhibitor of metalloproteinase 4; TSP-1: thrombospondin-1; UTR: untranslated region; VEGF: Vascular Endothelial Growth Factor; VSMC: vascular smooth muscle cell; Wnt1: Wnt family member 1.

Arteriovenous malformation presenting as traumatic subdural hematoma: A case report

Background:

Brain arteriovenous malformations (AVMs) are congenital aberrant connections between afferent arteries and draining veins with no intervening capillary bed or neural parenchyma. Other than seizures, the most common initial presentation of AVM is hemorrhage, which is typically intraparenchymal, subarachnoid, or intraventricular, and very rarely subdural.

Case Description:

This patient is a 66-year-old male with a history of atrial fibrillation, chronically anticoagulated with apixaban, who presented through emergency services after a fall. On presentation, computed tomography (CT) of the head showed a small, 6 mm right subdural hematoma, and the patient was neurologically intact. The hematoma was evacuated by burr hole craniotomy and placement of a subdural drain 12 days after the initial presentation due to worsening headaches and further hematoma expansion. Two weeks postevacuation, the patient was readmitted for seizures, and at this time, CT angiography showed no intracranial vascular lesion. Approximately 1 month later, the patient was readmitted for decreased responsiveness, and CT head at this time found right frontal intraparenchymal hemorrhage. On subsequent catheter angiography, the right frontal AVM was discovered. It was treated with preoperative embolization followed by surgical resection. Postoperatively, the patient followed commands and tracked with his eyes. There was spontaneous antigravity movement of the right upper extremity, but still no movement of the left upper or bilateral lower extremities.

Conclusion:

This case emphasizes the importance of maintaining a high index of suspicion for underlying vascular lesions when evaluating intracranial bleeding, even in the setting of traumatic history, particularly in cases of hematoma expansion.

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.

Stereotactic Radiosurgery for Brain Arteriovenous Malformations: Evaluation of Obliteration and Review of Associated Predictors

BACKGROUND

High arteriovenous malformation (AVM) obliteration rates have been reported with stereotactic radiosurgery (SRS), and multiple factors have been found to be associated with AVM obliteration. These predictors have been inconsistent throughout studies. We aimed to analyze our experience with linear accelerator (LINAC)-based SRS for brain AVMs, evaluate outcomes, assess factors associated with AVM obliteration and review the various reported predictors of AVM obliteration.

METHODS

Electronic medical records were retrospectively reviewed to identify consecutive patients with brain AVMs treated with SRS over a 27-year period with at least 2 years of follow-up. Logistic regression analysis was performed to identify factors associated with AVM obliteration.

RESULTS

One hundred twenty-eight patients with 142 brain AVMs treated with SRS were included. Mean age was 34.4 years. Fifty-two percent of AVMs were associated with a hemorrhage before SRS, and 14.8% were previously embolized. Mean clinical and angiographic follow-up times were 67.8 months and 58.6 months, respectively. The median Spetzler-Martin grade was 3. Mean maximal AVM diameter was 2.8 cm and mean AVM target volume was 7.4 cm³ with a median radiation dose of 16 Gy. Complete AVM obliteration was achieved in 80.3%. Radiation-related signs and symptoms were encountered in 32.4%, only 4.9% of which consisted of a permanent deficit. Post-SRS AVM-related hemorrhage occurred in 6.3% of cases. In multivariate analysis, factors associated with AVM obliteration included younger patient age (P = .019), male gender (P = .008), smaller AVM diameter (P = .04), smaller AVM target volume (P = .009), smaller isodose surface volume (P = .005), a higher delivered radiation dose (P = .013), and having only one major draining vein (P = .04).

CONCLUSIONS

AVM obliteration with LINAC-based radiosurgery was safe and effective and achieved complete AVM obliteration in about 80% of cases. The most prominent predictors of AVM success included AVM size, AVM volume, radiation dose, number of draining veins and patient age.

An enormous arteriovenous malformation presenting in a child in sacro-gluteal region and managed successfully by recurrent embolisation and surgery

BACKGROUND

Arteriovenous malformations (AVMs) are rare congenital lesions that affect multiple regions. AVMs often affect the brain and the buttock is the least common. They are usually congenital, but discovered later in life as they are asymptomatic, small and resemble a benign lesion. However, they can abruptly grow and become symptomatic and life-threatening as they can bleed and get infected.

PRESENTATION OF CASE

An eight-year-old girl presented with ulcerated and bleeding AVM at the sacro gluteal region. However, due to financial difficulty, it grew to reach an enormous size of (15*15*2 cm) in the buttock. It was later managed by multiple embolisation followed by total surgical resection.

DISCUSSION

This case reflects the first case of enormous AVM in the sacro-gluteal region in a child in the Middle East as they rarely reach such huge sizes. Total resection was possible by repeat embolisation and surgery.

CONCLUSION

Embolisation can render even huge AVM operable. AVMs should be treated as early as possible as they continue to grow and drastically decrease the quality of life of the patient.

Stasis index from hemodynamic analysis using quantitative DSA correlates with hemorrhage of supratentorial arteriovenous malformation: a cross-sectional study

OBJECTIVE

Assessments of hemorrhage risk based on angioarchitecture have yielded inconsistent results, and quantitative hemodynamic studies have been limited to small numbers of patients. The authors examined whether cerebral hemodynamic analysis using quantitative digital subtraction angiography (QDSA) can outperform conventional DSA angioarchitecture analysis in evaluating the risk of hemorrhage associated with supratentorial arteriovenous malformations (AVMs).

METHODS

A cross-sectional study was performed by retrospectively reviewing adult supratentorial AVM patients who had undergone both DSA and MRI studies between 2011 and 2017. Angioarchitecture characteristics, DSA parameters, age, sex, and nidus volume were analyzed using univariate and multivariate logistic regression, and QDSA software analysis was performed on DSA images. Based on the QDSA analysis, a stasis index, defined as the inflow gradient divided by the absolute value of the outflow gradient, was determined. The receiver operating characteristic (ROC) curve was used to compare diagnostic performances of conventional DSA angioarchitecture analysis and analysis using hemodynamic parameters based on QDSA.

RESULTS

A total of 119 supratentorial AVM patients were included. After adjustment for age at diagnosis, sex, and nidus volume, the exclusive deep venous drainage (p < 0.01), observed through conventional angioarchitecture examination using DSA, and the stasis index of the most dominant drainage vein (p = 0.02), measured with QDSA hemodynamic analysis, were independent risk factors for hemorrhage. The areas under the ROC curves for the conventional DSA method (0.75) and QDSA hemodynamics analysis (0.73) were similar. A venous stasis index greater than 2.18 discriminated the hemorrhage group with a sensitivity of 52.6% and a specificity of 81.5%.

CONCLUSIONS

In QDSA, a higher stasis index of the most dominant drainage vein is an objective warning sign associated with supratentorial AVM rupture. Risk assessments of AVMs using QDSA and conventional DSA angioarchitecture were equivalent. Because QDSA is a complementary noninvasive approach without extra radiation or contrast media, comprehensive hemorrhagic risk assessment of cerebral AVMs should include both DSA angioarchitecture and QDSA analyses.

Cognitive performance in patients with cerebral arteriovenous malformation

OBJECTIVE

A cerebral arteriovenous malformation (cAVM) can change over time and cause symptoms, but clinical studies tend to define only the patients with ruptured cAVMs as symptomatic and do not consider neurocognitive aspects prior to neurosurgical intervention. The objective of this study was to describe the neurocognitive function of patients with ruptured and unruptured cAVMs according to the Spetzler-Martin (SM) grade, flow status, and anatomical topography.

METHODS

In this blinded cross-sectional study, 70 patients of both sexes and ages 18-60 years were evaluated using the Brazilian Brief Neuropsychological Assessment Battery Neupsilin.

RESULTS

Of the 70 patients with cAVMs, 50 (71.4%) demonstrated deficits in at least one of the eight neurocognitive domains surveyed, although they did not exhibit neurological deficits. cAVMs in the temporal lobe were associated with memory deficits compared with the general population. The SM grade was not significantly associated with the results of patients with unruptured cAVMs. However, among patients with ruptured cAVMs, there were deficits in working memory in those with high-grade (SM grade) cAVMs and deficits in executive function (verbal fluency) in those with low-grade cAVMs (p < 0.001).

CONCLUSIONS

This study indicates that patients with untreated cAVMs, either ruptured or unruptured, already exhibit neurocognitive deficits, even the patients without other neurological symptoms. However, the scales used to evaluate disability in the main clinical studies, such as A Randomized Trial of Unruptured Brain Arteriovenous Malformations (ARUBA), do not assess neurocognitive alterations and therefore disregard any deficits that may affect quality of life. The authors' finding raises an important question about the effects of interventional treatment because it reinforces the hypothesis that cognitive alterations may be preexisting and not determined by interventions.

Outcome Comparison Between Surgically Treated Brain Arteriovenous Malformation Hemorrhage and Spontaneous Intracerebral Hemorrhage

BACKGROUND

Case fatality and poor outcome rates are different between brain arteriovenous malformation-associated intracerebral hemorrhage (bAVM-ICH) and spontaneous intracerebral hemorrhage (SICH). These outcome rates, however, have never been compared in patients who need neurosurgical evacuation of the intracerebral hemorrhage (ICH).

OBJECTIVE

To compare the short- and long-term functional outcome between surgically treated patients with bAVM-ICH and SICH.

METHODS

We collected data from surgically treated ICH patients at the Department of Neurosurgery, University Hospital Zurich, from January 2015 to July 2018. We performed logistic regression analysis to compare the functional outcome between groups, adjusting for demographics, admission characteristics, and stroke risk factors.

RESULTS

A total of 26 bAVM-ICH and 115 SICH patients were included in the final analysis. Patients with bAVM-ICH were younger and less likely to have hypertension without significant differences in ICH volume, hematoma location, intraventricular hemorrhage, and other stroke risk factors. A significantly better functional outcome rate was seen in bAVM-ICH patients at short- and long-term follow-up. These differences remained significant after adjusting for confounders.

CONCLUSIONS

patients with a bAVM who need surgical evacuation of an ICH have a more favorable outcome than surgically treated patients with spontaneous ICH, even after correction for confounding factors, such as younger age and less premorbid hypertension.

Intracranial Gorgon: Surgical Case Report of a Large Calcified Brain Arteriovenous Malformation

Patient: Male, 55-year-old

Final Diagnosis: Right frontal arteriovenous malformation, partially calcified • multiple generalised epileptic seizures • chronic headache

Symptoms: Epilectic seizure • headache

Medication: —

Clinical Procedure: Neurosurgical resection of the right frontal AVM

Specialty: Neurosurgery

Clinical Outcomes of Stereotactic Radiosurgery for Cerebral Arteriovenous Malformations in Pediatric Patients: Systematic Review and Meta-Analysis

BACKGROUND

Arteriovenous malformations (AVMs) in pediatric patients exhibit remarkable differences in terms of management and outcomes. Owing to a paucity of relevant data pertaining to AVMs in pediatric patients, special interest and investigation are required for an improved understanding of the available evidence by clinicians.

OBJECTIVE

To determine the clinical outcomes of single-session stereotactic radiosurgery (SRS) for AVMs in pediatric patients.

METHODS

A systematic literature review was performed to identify studies that reported the outcomes of SRS for AVMs in pediatric patients. Data pertaining to variables such as obliteration rate, post-SRS new hemorrhage rate, post-SRS new neurological deficit rate, and mortality rate were extracted and analyzed using meta-analysis techniques.

RESULTS

Based on pooled data from 20 studies with 1212 patients, single-session SRS resulted in complete obliteration in 65.9% (95% confidence interval [CI], 60.5%-71.1%; I2 = 66.5%) patients. Overall complication rate (including new hemorrhage, new neurodeficit, and mortality) was 8.0% (95% CI, 5.1%-11.5%; I2 = 66.4%). Post-SRS new neurological deficit rate was 3.1% (95% CI, 1.3%-5.4%; I2 = 59.7%), and post-SRS hemorrhage rate was 4.2% (95% CI, 2.5%-6.3%; I2 = 42.7%). There was no significant difference between studies disaggregated by treatment method (Gamma Knife [Elekta AB] vs other), treatment year (before year 2000 vs after year 2000), median AVM volume reported (≥3 vs <3 cm3), median dose reported (≥20 vs <20 Gy), or follow-up period (≥36 vs <36 mo).

CONCLUSION

Single-SRS is a safe treatment alternative that achieves high obliteration rates and acceptable complication rates for AVMs in pediatric patients.

Endovascular treatment of cerebellar arteriovenous malformations: A single-center experience of 75 consecutive patients

AIM

We aimed to determine the safety and effectiveness of endovascular treatment for cerebellar arteriovenous malformations (AVMs).

MATERIALS AND METHODS

Between January 2006 and January 2016, 75 patients with cerebellar AVMs underwent endovascular treatment at our department. The clinical and angiographic features, post-procedure complications, occlusion rate, and follow-up outcomes (modified Rankin Scale, mRS) of all the patients were retrospectively reviewed and collected. Multivariable logistic analysis was used to calculate potential risk factors for predicting poor outcomes (mRS ≥3).

RESULTS

Of the 75 patients, 61 (81.3%) presented with initial hemorrhage, and 44 (58.7%) presented with 63 cerebral aneurysms. Immediate digital subtraction angiography (DSA) after the procedure showed complete occlusion of the cerebral aneurysms in all the patients, and total occlusion of the AVM nidus in 32/75 (42.7%) patients, 99-90% occlusion in 31/75 (41.3%) patients, and <90% occlusion in 12/75 (16.0%) patients. Favorable functional outcome (mRS <3) was achieved in 61 (81.3%) patients. After adjusting for other factors, multivariate logistic analysis showed that increasing patient age (OR, 1.086; 95% CI, 1.098-1.182), the size of AVM (OR, 9.072; 95% CI, 1.164-20.703), and eloquent location (OR, 9.209; 95% CI, 1.557-35.481) were significantly independent predictors of poor outcome.

CONCLUSIONS

Endovascular treatment of cerebellar AVMs is safe and feasible. The high rate of associated cerebral aneurysms could explain the tendency of initial hemorrhage in cerebellar AVMs; targeted embolization of coexisting cerebral aneurysms should be the first priority. Increasing patient age, eloquent AVM location, and the size of AVM are independent predictors of poor outcome after endovascular treatment of cerebellar AVMs.

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.

Occlusion of Animal Model Arteriovenous Malformations Using Vascular Targeting

Brain arteriovenous malformations (AVMs) are a significant cause of intracerebral hemorrhage in children and young adults. Currently, one third of patients have no viable treatment options. Vascular targeting agents (VTAs) are being designed to deliver pro-thrombotic molecules to the abnormal AVM vessels for rapid occlusion and cure. This study assessed the efficacy of a pro-thrombotic VTA targeting phosphatidylserine (PS) in a radiation-primed AVM animal model. The model AVM was surgically created in rats by anastomosis of the left external jugular vein to the adjacent common carotid artery. After 6 weeks, the AVM was irradiated (20 Gy) using gamma knife surgery (GKS). A PS-targeting VTA was created by conjugation of annexin V with human thrombin and administered intravenously 3 weeks post-GKS or sham. Unconjugated thrombin was used as a non-targeting control. AVM thrombosis and occlusion was monitored 3 weeks later by angiography and histology. Preliminary experiments established a safe dose of active thrombin for systemic administration. Subsequently, a single dose of annexin V-thrombin conjugate (0.77 mg/kg) resulted in angiographic AVM occlusion in sham (75%) and irradiated (63%) animals, while non-targeted thrombin did not. Lowering the conjugate dose (0.38 mg/kg) decreased angiographic AVM occlusion in sham (13%) relative to irradiated (80%) animals (p = 0.03) as did delivery of two consecutive doses of 0.38 mg/kg, 2 days apart (sham (0%); irradiated (78%); p = 0.003). These findings demonstrate efficacy of the PS-targeting VTA and the feasibility of a vascular targeting approach for occlusion of high-flow AVMs. Targeting specificity can be enhanced by radiation-sensitization and VTA dose modification.

Congenital Retinal Macrovessel and the Association of Retinal Venous Malformations With Venous Malformations of the Brain

Importance

Congenital retinal macrovessel (CRM) is a rarely reported venous malformation of the retina that is associated with venous anomalies of the brain.

Objective

To study the multimodal imaging findings of a series of eyes with congenital retinal macrovessel and describe the systemic associations.

Design, Setting, and Participants

In this cross-sectional multicenter study, medical records were retrospectively reviewed from 7 different retina clinics worldwide over a 10-year period (2007-2017). Patients with CRM, defined as an abnormal, large, macular vessel with a vascular distribution above and below the horizontal raphe, were identified. Data were analyzed from December 2016 to August 2017.

Main Outcomes and Measures

Clinical information and multimodal retinal imaging findings were collected and studied. Pertinent systemic information, including brain magnetic resonance imaging findings, was also noted if available.

Results

Of the 49 included patients, 32 (65%) were female, and the mean (SD) age at onset was 44.0 (20.9) years. A total of 49 eyes from 49 patients were studied. Macrovessel was unilateral in all patients. Color fundus photography illustrated a large aberrant dilated and tortuous retinal vein in all patients. Early-phase frames of fluorescein angiography further confirmed the venous nature of the macrovessel in 40 of 40 eyes. Optical coherence tomography angiography, available in 17 eyes (35%), displayed microvascular capillary abnormalities around the CRM, which were more evident in the deep capillary plexus. Of the 49 patients with CRM, 39 (80%) did not illustrate any evidence of ophthalmic complications. Ten patients (20%) presented with retinal complications, typically an incidental association with CRM. Twelve patients (24%) were noted to have venous malformations of the brain with associated magnetic resonance imaging. Of these, location of the venous anomaly in the brain was ipsilateral to the CRM in 10 patients (83%) and contralateral in 2 patients (17%), mainly located in the frontal lobe in 9 patients (75%).

Conclusions and Relevance

Our study has identified an association between macrovessels in the retina and venous anomalies of the brain (24% compared with 0.2% to 6.0% in the normal population). Thus, we recommend new guidelines for the systemic workup of patients with CRM to include brain magnetic resonance imaging with contrast. These lesions may be more accurately referred to as retinal venous malformations, which may raise awareness regarding potential cerebral associations.

Ratio of Arteriovenous Malformation Draining Vein to Adjacent Venous Sinus Diameter Is Associated with Increased Risk of Venous Stenosis

BACKGROUND

The development of venous outflow stenosis in cerebral arteriovenous malformation (AVM) is poorly understood. The location of stenosis within the AVM draining vein in relation to the adjacent venous sinus and the hypothesis that the ratio of draining vein to adjacent sinus diameter might predict the development of venous stenosis were explored.

METHODS

Patients with supratentorial AVMs (1997-2018) were reviewed (N = 290). AVM draining vein and adjacent venous sinus diameters, degree of draining vein stenosis, and distance from the maximal stenotic point to the junction of the adjacent draining sinus were recorded. Correlation between percentage of AVM draining vein stenosis and the ratio of AVM draining vein to venous sinus diameters was analyzed.

RESULTS

A total of 360 draining veins in 243 AVMs with complete angiographic data were measured. Venous stenosis (in 131 draining veins) was observed within 20 mm of the junction to the adjacent draining sinus in 85% of our sample. The ratio of draining vein to adjacent sinus diameter correlated positively with the percentage of venous stenosis (P < 0.01, r = 0.21). The ratio between 0.51-1.0 and >1.0 showed significant tighter stenosis compared with the ratio ≤0.5 (25.9% and 28.9% vs. 10.0%, respectively; P < 0.01).

CONCLUSIONS

AVM venous outflow stenosis is observed close to the adjacent venous sinus junction. The degree of venous stenosis is greater when the ratio of AVM draining vein/adjacent venous sinus diameter is >0.5. This may be related to more turbulent flow at the junction of the draining vein and venous sinus, especially in larger draining veins, which causes venous stenosis to develop over time.

Oculomotor neuropathy from an unruptured arteriovenous malformation in the frontal operculum: A case report

Background:

Cerebral arteriovenous malformations (AVMs) are vascular lesions with a network of dysplastic vessels between an arterial and a venous tree with no intervening capillary bed. They most commonly present with an acute hemorrhage, seizures, or persistent headaches.

Case Description:

The authors report the case of a 62-year-old male who presented with diplopia for 5 days. Magnetic resonance imaging and angiography demonstrated a Spetzler-Martin Grade 2 AVM located in the right frontal operculum with deep drainage into the basal vein of Rosenthal causing ipsilateral oculomotor neuropathy. The patient underwent staged embolizations of the feeding pedicles, which were derived from the internal as well as external carotid circulation. This was followed by a right pterional craniotomy for resection of the AVM. The patient reported complete resolution of the diplopia over 4 weeks with no recurrence at the 6-month follow-up appointment.

Conlusion:

AVMs of the brain can present with atypical clinical symptoms that can be caused by the venous drainage pattern not the location. It is important to include vascular imaging studies in the work-up of patients who present with diplopia to rule out an AVM. Early diagnosis and treatment of the AVM can result in complete resolution of the diplopia.

Long-Term Outcomes for Pediatric Patients with Brain Arteriovenous Malformations Treated with Gamma Knife Radiosurgery, Part 1: Analysis of Nidus Obliteration Rates and Related Factors

OBJECTIVE

Little is known about long-term outcomes for pediatric brain arteriovenous malformations (AVMs) treated with Gamma Knife radiosurgery (GKRS). This study investigated annual hemorrhage rates and nidus obliteration rates, and the factors affecting them, in pediatric AVMs treated with GKRS.

METHODS

We examined 189 pediatric AVM patients (age ≤15 years) who underwent GKRS and had at least 12 months of follow-up. The Spetzler-Martin (S-M) grade was I in 29 patients (15%), II in 57 (30%), III in 82 (43%), IV in 16 (9%), and V in 5 (3%). The median treatment volume was 2.2 cm³, and the median marginal dose was 20 Gy.

RESULTS

The mean follow-up period was 136 months. During a cumulative latency period to nidus obliteration of 813 years, 23 hemorrhages occurred, resulting in an annual post-GKRS hemorrhage rate of 2.8%. The cumulative hemorrhage rates after GKRS were 3.3%, 8.5%, and 11.9% at 3, 5, and 10 years, respectively. Higher S-M grade was significantly associated with intracranial hemorrhages during the latency period (P < 0.001). The actuarial nidus obliteration rates with repeated GKRS were 64% and 81% at 5 and 10 years, respectively. Absence of pre-GKRS embolization (P = 0.023) and higher marginal dose (P = 0.029) were significant factors predicting nidus obliteration.

CONCLUSIONS

GKRS is a reasonable treatment option in pediatric AVMs to prevent future hemorrhages. Because higher S-M grade AVMs are more likely to hemorrhage during the latency period, a combined therapy with endovascular embolization should be considered to prevent AVM rupture.

Volume-Staged CyberKnife Stereotactic Radiosurgery for Treatment of Drug-Resistant Epilepsy for a Spetzler-Martin Grade V Arteriovenous Malformation: A Case Report and Review of the Literature

BACKGROUND

Evidence to support the use of stereotactic radiosurgery (SRS) in the treatment of epilepsy secondary to cerebral arteriovenous malformations (AVMs) is emerging. However, these studies have not clearly demonstrated the use of SRS in the treatment of drug-resistant epilepsy (DRE) in high Spetzler-Martin grade (IV-V) AVMs.

CASE DESCRIPTION

We present a 48-year-old woman with DRE secondary to a Spetzler-Martin grade V cerebral AVM. She was treated with volume-staged SRS (VS-SRS) and achieved near-complete resolution of her seizures with incomplete obliteration of the AVM. Six years after treatment, she has experienced no serious complications.

CONCLUSIONS

VS-SRS successfully controlled seizures (Engel Outcome Measure of 1A) in a patient with intractable, DRE secondary to a high-grade cerebral AVM.

Grades of brain arteriovenous malformations and risk of hemorrhage and death

Objective

To assess the relationship of the grade of unruptured and untreated Brain Arteriovenous Malformations (AVMs), with the risk of subsequent stroke and death during follow‐up.

Methods

This prospective study was drawn from a cohort of adult patients with unruptured AVMs, who participated in the conservative treatment arm (medical management only for headache or seizures) of the randomized clinical trial of unruptured brain AVMs (ARUBA study). The grade of AVMs (Spetzler–Martin scale) was dichotomized into categories: AVMs of grades I and II were considered low grade; AVMs of grades III and IV were considered high grade. There were no grade V AVM patients in ARUBA. The primary outcome was symptomatic stroke (hemorrhagic or ischemic – documented by imaging) or death.

Results

The conservative treatment group had 123 patients (“as treated” analysis). 71 (57.7%) had lesions characterized for this analysis as low‐grade lesions and 52 (42.2%) as high grade. From the total of 10 (8.13%) primary outcomes, three occurred (4.22%) in low‐grade AVMs and seven (13.46%) in high‐grade AVMs (P = 0.0942).

Interpretation

Statistical analysis of the cohort of patients with unruptured and untreated AVMs from ARUBA study showed that the graduation categories (Spetzler–Martin grades) were not associated with the outcome of subsequent stroke or death.

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.

Plasma D-Dimer Concentrations and Risk of Intracerebral Hemorrhage: A Systematic Review and Meta-Analysis

Background: The aim of our meta-analysis was to evaluate the association between plasma d-dimer and intracerebral hemorrhage (ICH).

Methods: Embase, Pubmed, and Web of Science were searched up to the date of March 19th, 2018, and manual searching was used to extract additional articles. Standard mean difference (SMD) with 95% confidence intervals (CI) was calculated to evaluate d-dimer levels.

Results: Thirteen studies including 891 ICH patients and 1,573 healthy controls were included. Our results revealed that higher levels of d-dimer were displayed in ICH patients than those in healthy controls (95% CI= 0.98–2.00, p< 0.001). Subgroup analysis based on continent of Asia and Europe, sample size, as well as age in relation to d-dimer levels between ICH patients and healthy controls did not change the initial observation; whereas no differences of d-dimer levels were found between ICH and controls in America.

Conclusions: This meta-analysis revealed that high level of d-dimer is associated with the risk of ICH. Plasma d-dimer is suggested to be a potential biomarker for patients with ICH in Asia and Europe rather than in America. There were no impact of sample size-related differences and age-related diversities on the risk of ICH with respect to d-dimer levels.

Microsurgical resection of brain arteriovenous malformations in the elderly: outcomes analysis and risk stratification

As the population ages, the question of how to manage brain arteriovenous malformations in the elderly becomes increasingly relevant. Is resection a reasonable option for these patients? In this study, the authors examined the outcomes of surgical patients 60 years or older and found that favorable outcomes were achieved with careful patient selection. Preoperative grading scales were more predictive of outcomes in patients older than 65 years than in those 60-65 years of age.

Treatment of Unruptured Brain Arteriovenous Malformations: A Single-Center Experience of 86 Patients and a Critique of the A Randomized Trial of Unruptured Brain Arteriovenous Malformations (ARUBA) Trial

OBJECTIVE

The A Randomized Trial of Unruptured Brain Arteriovenous Malformations (ARUBA) trial has received fierce criticism, including considerable selection bias, poor generalizability, questionable clinical practices (only 15.8% underwent surgical resection, the gold standard for arteriovenous malformation [AVM] treatment), and short follow-up (33 months) for a disease process that carries a life-long risk. In this study, we sought to present our own experience treating unruptured brain AVMs to provide supporting evidence of the ARUBA trial criticism.

METHODS

All cases of treated brain AVMs from 2004 to 2017 at our institution were retrospectively reviewed and included in the analysis if they met ARUBA trial inclusion criteria. The primary outcome was symptomatic stroke or death. Secondary outcomes included AVM obliteration, long-term clinical impairment (modified Rankin Scale score >1), and new major or minor postoperative deficit.

RESULTS

Of the 245 reviewed cases, 86 met the ARUBA trial criteria. Treatment included microsurgical resection alone (2.3%), preoperative embolization followed by microsurgical resection (62.8%), stereotactic radiosurgery alone (10.5%), embolization followed by stereotactic radiosurgery (15.1%), and embolization alone (9.3%). The primary outcome was met in 8.3%, new perioperative major and minor complications occurred in 5.8% and 12.8%, and long-term clinical impairment in 4.5%. AVM obliteration was observed in 92.4% overall and in 100% of patients who underwent surgical resection.

CONCLUSIONS

The criticism of the ARUBA trial is warranted, as our study found that treatment of unruptured brain AVMs has an acceptable safety profile when approached in a multidisciplinary manner at an experienced institution, using surgical resection as the primary treatment modality when applicable.

The Effect of Flow-Related Aneurysms on Hemorrhagic Risk of Intracranial Arteriovenous Malformations

BACKGROUND

Previous reports indicated an association between hemorrhagic presentation and flow-related aneurysms in arteriovenous malformation (AVM) patients. However, it remains unclear whether these flow-related aneurysms result in the hemorrhage of AVM.

OBJECTIVE

To characterize this hemorrhage risk using our institutional experience over 25 yr.

METHODS

We retrospectively reviewed records of patients at our institution diagnosed with AVM from 1990 to 2015. Patients without associated aneurysms (AVM only) and those with flow-related aneurysms (AVM-FA) were compared. Those with intranidal or unrelated aneurysms were excluded. Annual risk of AVM-related hemorrhage was calculated using the birth-to-treatment approach and compared using Poisson rate ratio test.

RESULTS

Among 526 patients, there were 457 AVM only patients and 69 with flow-related aneurysms. AVM-FA patients were older (P = .005). AVMs with flow-related aneurysms were more likely located in the cerebellar vermis and hemispheres (P = .023 and .001, respectively). Presence of flow-related aneurysms increased the risk of presentation with subarachnoid hemorrhage (P < .001). Interestingly, no significant differences in presenting hemorrhage due to AVM rupture were found (P > .356). The majority of aneurysms were untreated (69.5%), and only 8 (9.8%) had ruptured presentation. At follow-up (mean = 5.3 yr), patients with flow-related aneurysms were less likely to develop seizures (P = .004). The annual risk of AVM hemorrhage was 1.33% and 1.05% for AVM only patients and AVM-FA patients, respectively (P = .248).

CONCLUSION

Despite increased risk of subarachnoid hemorrhage at presentation, there was no increased likelihood of rupture in AVMs with flow-related aneurysms. More studies are warranted, as clarifying the competing risks of AVM vs aneurysm rupture may be critical in determining optimal treatment strategy.

Results of volume-staged fractionated Gamma Knife radiosurgery for large complex arteriovenous malformations: obliteration rates and clinical outcomes of an evolving treatment paradigm

OBJECTIVE There are few reported series regarding volume-staged Gamma Knife radiosurgery (GKRS) for the treatment of large, complex, cerebral arteriovenous malformations (AVMs). The object of this study was to report the results of using volume-staged Gamma Knife radiosurgery for patients affected by large and complex AVMs. METHODS Data from 20 patients with large AVMs were prospectively included in the authors' AVM database between 2004 and 2012. A staging strategy was used when treating lesion volumes larger than 10 cm³. Hemorrhage and seizures were the presenting clinical feature for 6 (30%) and 8 (40%) patients, respectively. The median AVM volume was 15.9 cm³ (range 10.1-34.3 cm³). The mean interval between stages (± standard deviation) was 15 months (± 9 months). The median margin dose for each stage was 20 Gy (range 18-25 Gy). RESULTS Obliteration was confirmed in 8 (42%) patients after a mean follow-up of 45 months (range 19-87 months). A significant reduction (> 75%) of the original nidal volume was achieved in 4 (20%) patients. Engel Class I-II seizure status was reported by 75% of patients presenting with seizures (50% Engel Class I and 25% Engel Class II) after radiosurgery. After radiosurgery, 71.5% (5/7) of patients who had presented with a worsening neurological deficit reported a complete resolution or amelioration. None of the patients who presented acutely because of hemorrhage experienced a new bleeding episode during follow-up. One (5%) patient developed radionecrosis that caused sensorimotor hemisyndrome. Two (10%) patients sustained a bleeding episode after GKRS, although only 1 (5%) was symptomatic. High nidal flow rate and a time interval between stages of less than 11.7 months were factors significantly associated with AVM obliteration (p = 0.021 and p = 0.041, respectively). Patient age younger than 44 years was significantly associated with a greater than 75% reduction in AVM volume but not with AVM obliteration (p = 0.024). CONCLUSIONS According to the results of this study, volume-staged GKRS is an effective and safe treatment strategy for large, complex, cerebral AVMs for which microsurgery or endovascular approaches could carry substantially higher risks to the patient. Radiation doses up to 20 Gy can be safely administered. The time interval between stages should be shorter than 11.7 months to increase the chance of obliteration. High nidal flow and a patient age younger than 44 years were factors associated with nidus obliteration and significant nidus reduction, respectively.

Pediatric brain arteriovenous malformation unfavorable hemorrhage risk: extrapolation to a morphologic model

Background

Children with brain arteriovenous malformations (bAVM) are at risk of life-threatening hemorrhage contributing to unfavorable neurological deficit in their early lives. Our aim was to propose a classification system predicting the unfavorable hemorrhage in children with bAVM.

Methods

We identified all consecutive children admitted to our institution for bAVMs between July 2009 and August 2015. A hemorrhage event was defined as unfavorable when it is life-threatening (requiring emergent invasive intervention) or with post-hemorrhage mRS > 3. The effects of demographic characteristics and bAVM morphology on unfavorable hemorrhage risk were studied using univariate and multivariable regression analyses, followed by discrimination analysis using area under the receiver operating curve (AUROC) and 5-fold cross validation.

Results

A total of 162 pediatric bAVM cases were identified, unfavorable hemorrhage occurred in 49 (30.2%). Periventricular nidus location (HR, 4.46; 95%CI, 1.93–10.31; P < 0.001), non-temporal lobe location (HR, 2.72; 95%CI, 1.20–6.15; P = 0.02) and long pial draining vein (HR, 3.26; 95%CI, 1.53–6.97; P = 0.002) were independent predictors of an earlier unfavorable hemorrhage in pediatric bAVMs. We further classified the bAVM into three types: Type I, periventricular and non-temporal location (Ia, deep location; Ib, superificial location); Type II, with long pial draining vein and non-periventricular or temporal location; Type III, non-periventricular or temporal location without long draining vein. Predictive accuracy of this classification for unfavorable hemorrhage was assessed with AUROC of 0.77 (95% CI 0.69–0.85) and remained stable after cross validation.

Conclusion

A morphologic model based on nidus location and venous drainage might predict unfavorable hemorrhage in children with bAVM.

Surgical Treatment vs Nonsurgical Treatment for Brain Arteriovenous Malformations in Patients with Hereditary Hemorrhagic Telangiectasia: A Retrospective Multicenter Consortium Study

BACKGROUND

Cerebral arteriovenous malformations (AVMs) are common in patients with hereditary hemorrhagic telangiectasia (HHT). However, due to the rarity of HHT and little published evidence of outcomes from management of brain AVMs in this disease, current international HHT guidelines recommend an individualized approach. Specifically, the outcomes for surgical vs nonsurgical management of these lesions have not been reported to date.

OBJECTIVE

To report long-term outcomes of surgical resection of brain AVMs in HHT patients compared to outcomes in nonsurgically treated patients.

METHODS

From the database of the Brain Vascular Malformation Consortium HHT project, 19 patients with 20 resected AVMs (group 1) and 22 patients with 33 AVMs who received nonsurgical treatment (group 2) were studied. The groups were retrospectively reviewed for changes in functional status (modified Rankin Scale score) during the follow-up period.

RESULTS

During the follow-up period, 9% of patients in group 1 suffered from worsening of functional status, whereas this figure was 16% for group 2 (P > .05). Functional outcomes were not statistically different between the 2 groups at the latest follow-up (P > .05).

CONCLUSION

HHT patients treated surgically for brain AVMs appear to have long-term functional outcomes comparable to nonsurgical (including observational) therapy with fewer unfavorable outcomes. It is therefore reasonable to consider surgical resection as a management option in the multidisciplinary team's individualized treatment strategy for HHT patients with brain AVMs.

Evaluation of Angioarchitectural Features of Unruptured Brain Arteriovenous Malformation by Susceptibility Weighted Imaging

OBJECTIVES

A precise assessment of angioarchitectural characteristics using noninvasive imaging is helpful for serial follow-up and weighting risk of natural history in unruptured brain arteriovenous malformation (bAVM). This study aimed to test the hypothesis that susceptibility weighted imaging (SWI) would provide an accurate evaluation of angioarchitectural features of unruptured bAVM.

METHODS

A total of 81 consecutive patients with unruptured bAVM were examined. Image quality of SWI for the assessment of bAVM angioarchitectural features was determined by a 5-point scale. The accuracy of SWI for detection of angioarchitectural features was evaluated using digital subtraction angiography as a standard reference and further compared among unruptured bAVMs with or without silent intralesional microhemorrhage on SWI to examine the potential confounding effect of microhemorrhage on image analysis.

RESULTS

All lesions were identified on SWI. Image quality of SWI was judged to be at least adequate for diagnosis (range, 3-5) in all patients by both readers. Using digital subtraction angiography as a reference standard, the area under the receiver operating curve of detection of deep or posterior fossa location, exclusively deep venous drainage, venous ectasia, venous varices, and the presence of associated aneurysm on SWI was 1, 0.93, 0.94, 0.95, and 0.83, respectively. Silent intralesional microhemorrhage were detected in 39 patients (48.15%) on SWI and no significant difference (P > 0.05) was found in angioarchitectural features between patients with and without silent microhemorrhage.

CONCLUSIONS

SWI might be a noninvasive alternative technique for angiography in the angioarchitectural assessment of unruptured bAVM.

Safety and efficacy of endovascular therapy and gamma knife surgery for brain arteriovenous malformations in China: Study protocol for an observational clinical trial

Introduction

Brain arteriovenous malformations (BAVMs) are associated with high morbidity and mortality. The treatment of BAVM remains controversial. Microinvasive treatment, including endovascular therapy and gamma knife surgery, has been the first choice in many conditions. However, the overall clinical outcome of microinvasive treatment remains unknown and a prospective trial is needed.

Methods

This is a prospective, non-randomized, and multicenter observational registry clinical trial to evaluate the safety and efficacy of microinvasive treatment for BAVMs. The study will require up to 400 patients in approximately 12 or more centers in China, followed for 2 years. Main subjects of this study are BAVM patients underwent endovascular therapy and/or gamma knife surgery. The trial will not affect the choice of treatment modality. The primary outcomes are perioperative complications (safety), and postoperative hemorrhage incidence rate and complete occlusion rate (efficacy). Secondary outcomes are elimination of hemorrhage risk factors (coexisting aneurysms and arteriovenous fistula), volume reduction and remission of symptoms. Safety and efficacy of endovascular therapy, gamma knife surgery, and various combination modes of the two modalities will be compared. Operative complications and outcomes at pretreatment, post-treatment, at discharge and at 3 months, 6 months and 2 years follow-up intervals will be analyzed using the modified Rankin Scale (mRS).

Discussion

The most confusion on BAVM treatment is whether to choose interventional therapy or medical therapy, and the choice of interventional therapy modes. This study will provide evidence for evaluating the safety and efficacy of microinvasive treatment in China, to characterize the microinvasive treatment strategy for BAVMs.

Long-term Outcomes With Planned Multistage Reduced Dose Repeat Stereotactic Radiosurgery for Treatment of Inoperable High-Grade Arteriovenous Malformations: An Observational Retrospective Cohort Study

BACKGROUND

There is no consensus regarding the optimal management of inoperable high-grade arteriovenous malformations (AVMs). This long-term study of 42 patients with high-grade AVMs reports obliteration and adverse event (AE) rates using planned multistage repeat stereotactic radiosurgery (SRS).

OBJECTIVE

To evaluate the efficacy and safety of multistage SRS with treatment of the entire AVM nidus at each treatment session to achieve complete obliteration of high-grade AVMs.

METHODS

Patients with high-grade Spetzler-Martin (S-M) III-V AVMs treated with at least 2 multistage SRS treatments from 1989 to 2013. Clinical outcomes of obliteration rate, minor/major AEs, and treatment characteristics were collected.

RESULTS

Forty-two patients met inclusion criteria (n = 26, S-M III; n = 13, S-M IV; n = 3, S-M V) with a median follow-up was 9.5 yr after first SRS. Median number of SRS treatment stages was 2, and median interval between stages was 3.5 yr. Twenty-two patients underwent pre-SRS embolization. Complete AVM obliteration rate was 38%, and the median time to obliteration was 9.7 yr. On multivariate analysis, higher S-M grade was significantly associated ( P = .04) failure to achieve obliteration. Twenty-seven post-SRS AEs were observed, and the post-SRS intracranial hemorrhage rate was 0.027 events per patient year.

CONCLUSION

Treatment of high-grade AVMs with multistage SRS achieves AVM obliteration in a meaningful proportion of patients with acceptable AE rates. Lower obliteration rates were associated with higher S-M grade and pre-SRS embolization. This approach should be considered with caution, as partial obliteration does not protect from hemorrhage.

Surgical treatment for refractory epilepsy

The goal of any epilepsy surgery is to improve patient's quality of life by achieving seizure freedom or by reducing the frequency of severely debilitating seizures. To achieve this goal, non-invasive and invasive diagnostic methods must precisely delineate the epileptogenic zone (EZ), which is defined as the area that needs to be resected to obtain seizure freedom. At the same time, the correct identification of eloquent brain areas is inevitable to avoid new neurological deficits from surgery. In recent years, the technical advances in diagnostics have enabled us to achieve these goals in an increasing number of cases. As a consequence, and with new surgical treatment options available, the number of patients who might benefit from epilepsy surgery is constantly increasing. Especially in pediatric epilepsy, early surgical intervention is becoming frequently advocated as it has been shown to improve cognitive and behavioral outcome. Specialized epilepsy centers and multidisciplinary teams are required to provide adequate care and treatment. The goal of this review is to describe important diseases that are accessible to epilepsy surgery and to give an overview of current diagnostic methods. The focus lies on established as well as novel techniques in epilepsy surgery. The presurgical work-up and patient selection is outlined.

Preoperative Embolization in Tandem with Surgical Resection for Cerebral Arteriovenous Malformations

A number of treatment options are available for cerebral arteriovenous malformations (AVMs) including surgical resection, stereotactic radiosurgery, and endovascular embolization. Endovascular embolization may be used pre-operatively to reduce the size of large AVMs and thus reduce surgical complications. Here we present two patients who successfully underwent preoperative embolization of their AVMs and subsequent surgery. Preoperative embolization is a viable option for AVMs to reduce complications and improve patient outcomes.