Cerebral Arteriovenous Malformations Research Articles

DECISION MAKING IN EPILEPTIC AVMS

While there is no doubt about the need for surgical treatment of a ruptured arteriovenous malformation (AVM), the decision to surgically treat a patient presenting solely with seizures is more controversial. Arteriovenous malformations (AVMs) arise from an abnormal connection between high-flow arterial vessels and low-flow venous vessels, resulting in a dysplastic vascular nidus within the brain tissue. The inherent flow irregularities within AVMs make them prone to rupture, which occurs in approximately half of patients. Additionally, seizures represent the second most common clinical manifestation of AVMs, presenting in 20%–45% of individuals with these lesions. This paper investigates the angiographic and MRI features of arteriovenous malformations that present with epilepsy, and discusses the surgical considerations in managing these patients and integration of multimodal approach focusing on the standard microsurgical techniques utilized. Patients presenting with seizures as the primary symptom of an arteriovenous malformation carry a higher surgical risk compared to those presenting with haemorrhage. Several factors have been associated with an increased risk of seizures in patients with arteriovenous malformations (AVMs). These include male gender, younger patient age, AVMs located in the frontal or temporal lobes, AVMs situated in the brain cortex, superficial venous drainage, a superficial temporal lobe AVM nidus, fistulous AVMs, and AVMs with venous stenosis. Surgical treatment is the recommended approach for patients with Spetzler-Martin grade I–III arteriovenous malformations. Resecting an unruptured brain arteriovenous malformation in a patient presenting only with epilepsy is a complex decision that requires a thorough understanding of the lesion’s anatomy, the patient’s history, and the neurosurgeon’s skills.

Clinical Presentations and Treatment Approaches in a Retrospective Analysis of 128 Intracranial Arteriovenous Malformation Cases

Background: Intracranial AVMs are a highly heterogeneous group of lesions that, while not very common, can pose significant risks. The therapeutic management of AVMs is complicated by ambiguous guidelines, particularly regarding which Spetzler–Martin grades should dictate specific treatment options. This study analyzed the clinical presentations and treatment approaches of 128 brain AVM cases managed between 2014 and 2022 at the National Institute of Neurology and Neurovascular Diseases in Bucharest, Romania. Methods: A retrospective analysis was conducted on patient demographics, clinical symptoms, Spetzler–Martin categorization, nidus localization, therapeutic management, and outcomes. Statistical analysis was performed using Python 3.10. Results: In our cohort of patients, the median age was 45 years, with a slight male predominance (67 males, 61 females). At admission, 51.5% presented with elevated blood pressure. The majority of patients had a Spetzler–Martin score of 2 (37.5%), followed by scores of 3 (31.3%) and 1 (20.3%). Treatment strategies included microsurgical resection in 32% of cases, conservative management in 31.2%, Gamma Knife radiosurgery in 22.6%, and endovascular embolization in 13.3%. Notably, open surgery was predominantly chosen for Grade II AVMs. The functional outcomes were favorable, with 69.5% achieving a good recovery score on the Glasgow Outcome Scale. Only four in-hospital deaths occurred, all in patients who underwent open surgery, and no deaths were recorded during the two-year follow-up. Conclusions: AVMs within the same Spetzler–Martin grade display considerable complexity, necessitating personalized treatment strategies. Our findings highlight the limitations of open surgery for Grade I cases but affirm its effectiveness for Grade II AVMs.

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

Chronic inflammation's role in the pathogenesis, development, and rupture of vascular malformations is undebated. Advanced magnetic resonance imaging techniques with vessel wall studies, specifically Black Blood (bbMRI), may offer insights into vascular wall instability and predict rupture. This case series aims to assess bbMRI as a predictive diagnostic tool for brain arteriovenous malformations (bAVMs) rupture, suggesting early treatment. A prospective study included demographic, clinical, and neuroimaging data from a consecutive series of patients with ruptured or unruptured bAVMs, regardless of age or gender, between October 2018 and March 2024. All patients underwent MRI brain resonance with Black Blood study. Those with impaired renal function were excluded. Statistical analyses tested sample homogeneity. Univariate and multivariate logistical regressions assessed bbMRI as a rupture predictor for bAVMs, with a p-value set at < 0.05. Ninety patients were retrieved: 64 with unruptured and 26 with ruptured bAVMs. The mean age was 31.9 years, and 55 were female. Admission symptoms were headache, neurological deficits, and seizure in 49, 21, and 19 cases, respectively. bbMRI showed wall enhancement in 56 cases, with 19 in the ruptured and 37 unruptured groups. Univariate and multivariate analyses revealed a significant correlation between bbMRI wall enhancement and bAVM rupture (p:0.033; p:0.047). bbMRI may be a useful and feasible diagnostic implement to determine vessel inflammation and the bAVMs prone to rupture. Additional studies are needed to confirm the positive bbMRI as a predictive factor for bAVMs rupture.

Brain and lung arteriovenous malformation rescreening practices for children and adults with hereditary hemorrhagic telangiectasia

BackgroundPatients with hereditary hemorrhagic telangiectasia (HHT) are at risk for organ vascular malformations including arteriovenous malformations (AVMs) in the brain and lungs. North American HHT Centers of Excellence (CoEs) routinely screen for brain and lung AVMs, with the primary goal of detecting AVMs which can be treated before complications arise. Current international HHT guidelines provide recommendations for initial screening for brain and lung AVMs among children and adults with the disease, but rescreening recommendations are not comprehensively addressed and have not been reported. We determined current rescreening practices for brain and lung AVMs for children and adults with HHT among North American HHT CoEs.MethodsWe surveyed North American HHT CoEs regarding rescreening practices for new brain and lung AVMs in children and adults with initial negative screening.ResultsAll thirty CoEs responded; 28 regarding pediatric (93.3%) and 30 (100%) regarding adult HHT care. The median duration of practice experience in HHT was 11.5 (range 3–30) years for providers of pediatric HHT care and 11.5 (range 3–35) years for providers of adult HHT care. The median number of patients followed at each CoE was 60 for children (range 8–500) and 375 for adults (range 30–1500). 25/28 CoEs (89.3%) reported rescreening children for brain AVMs, most commonly with enhanced MRI (21/25, 84%). 25 CoEs rescreen children for lung AVMs, most commonly every 5 years (15/25). Only 4/30 CoEs (13.3%) rescreen adults for brain AVMs. 26/30 CoEs (86.7%) reported rescreening adults for lung AVMs, most commonly every 5 years (18/26, 69.2%).ConclusionsMost HHT CoEs routinely rescreen children for brain and lung AVMs and adults for lung AVMs when initial screening is negative, but adults are infrequently rescreened for brain AVMs. Long-term data regarding risk for new brain and lung AVMs are required to establish practice guidelines for rescreening.

Can angiogenesis be reliably determined on digital subtraction angiography in cerebral arteriovenous malformations?

Background Angiogenesis and nascent blood vessel formation is thought to be important in cerebral arteriovenous malformation (cAVM) development and maintenance, of which little is known. Digital subtraction angiogram (DSA) features of angiogenesis in cAVMs are poorly described and the aim of this study was to describe the frequency of angiogenesis in patients who had a DSA showing a cAVM. We also sought to evaluate the intra- and inter-observer agreement of a diagnosis of angiogenesis and explore which angioarchitectural features were associated with angiogenesis. Method Patients that underwent a DSA were identified from the database of referred cAVM patients at the Manchester Centre for Clinical Neurosciences. Data were collected from 100 patients (102 cAVMs). cAVM angioarchitecture, including the presence of angiogenesis, was described after reviewing cAVM patient angiograms. The association of angioarchitectural features with angiogenesis was determined using univariate analysis. Ten cases were distributed amongst two other observers for reporting (inter-observer agreement). Twenty cases (including the previous 10) were reported twice by the first author, after a six-month interval (intra-observer agreement). Results Angiogenesis was observed in 39 cAVMs (38.2%), with 12 having a complete border (11.8%). Most intra-observer agreement was strong (ranging from κ = 1 to 0.2), but inter-observer agreement was moderate (κ = 1 to −0.316). There was a significant association between angiogenesis and venous reflux (OR 2.52 [95% CI = 1.08–5.88]), venous congestion (OR 4.47 [95% CI = .671–2.52]), arterial ectasia (OR 16.6 [95% CI = 4.65–59.6]), and artery: vein ratio (4.28 [95% CI = .956–19.15]). Conclusion We have demonstrated perinidal angiogenesis can be visualised on angiograms with moderate reliability, and that it may be related to angioarchitectural characteristics associated with venous hypertension.

The Correlation of Vessel Wall Macrophage Infiltration with Hemosiderin in Arteriovenous Malformations

Endothelial dysfunction, induced by high shear stress from increased nidal blood flow, may promote a cycle of inflammation, possibly leading to instability and cerebral arteriovenous malformations (AVMs) rupture. Macrophages, identified with CD68, are key inflammatory components in AVM pathology. We aim to evaluate the relationship of inflammation with AVM flow and hemosiderin. This is a retrospective study of archived tissue. Adult patients (2002-2022) with baseline quantitative magnetic resonance angiography (QMRA) imaging, no embolization, and history of microsurgical resection (n=17), with both ruptured (n=9) and unruptured cases (n=8). Brain AVM sections were stained with CD68 to quantify vessel wall macrophage infiltration and hematoxylin and eosin stain as a control and to quantify hemosiderin. QMRA with noninvasive optimal vessel analysis (NOVA) was reviewed, and AVM flow was calculated. Statistical analyses were performed. There were no significant differences between macrophage infiltration and patient demographics, Spetzler-Martin grade, eloquence, venous stenosis, nidus compactness, volume, and AVM flow. Vessel wall macrophage infiltration positively correlated with patients who presented with confirmed AVM rupture (163.8 +/- 46.7 vs. 101.3 +/- 49.4, p=0.017). Increases in vessel wall macrophage infiltration were found to positively correlate with higher grades of hemosiderin (p=0.023), except for grade 4 hemosiderin. Venous anomaly showed a negative association with macrophage infiltration (p=0.035). These findings suggest a relationship between AVM vessel wall inflammation, hemosiderin, and hemorrhage presentation. Further investigations with larger sample sizes are warranted to understand the role of altered hemodynamics, hemosiderin deposition and inflammation in AVM vessel walls.

Venous aneurysms in unruptured supratentorial brain arteriovenous malformations: a protective factor against hemorrhagic stroke and insights into hemodynamic mechanisms.

This study endeavors to clarify the impact of venous aneurysms (VA) on hemorrhagic risk in brain arteriovenous malformations (AVMs) and uncover potential hemodynamic mechanisms, utilizing quantitative digital subtraction angiography (QDSA) technology and survival dataset. Patients were enrolled in a multicenter prospective collaboration registry between August 2011 and August 2021, and subsequently categorized into the VA and non-VA cohorts. Using propensity score-matched survival analysis, we quantitatively assessed the natural risk of hemorrhagic stroke in these two cohorts. Additionally, a quantitative hemodynamic analysis was conducted to explore the distinctions in hemodynamic characteristics between these two cohorts. Among 3758 consecutive AVMs documented at a single center from the registry, 820 unruptured AVMs who maintained conservation management over 1 month were identified. Following a two-step matching process, 504 cases were retained for survival analysis and 408 cases for hemodynamic analysis. Overall, the presence of VA emerged as a protective factor, associated with a decreased risk of hemorrhagic stroke (HR, 0.21 [95% CI: 0.07-0.62], p = 0.004). Distinct hemodynamic characteristics were observed in AVMs with VA, showing a lower stasis index in two components of AVMs-the nidus (p = 0.014) and the main draining vein (p = 0.018). In this observational prospective cohort study, the presence of VA is associated with a decreased risk of hemorrhagic stroke in AVMs, suggesting an underlying hemodynamic mechanism involving the redistribution of excessive pressure loads within the AVM nidus by the VA. Questions What impact, if any, does VA have on the hemorrhagic risk in brain AVMs? Findings Presence of VA is associated with a decreased hemorrhagic stroke risk through the redistribution of pressure loads. Critical relevance VA in brain AVMs emerges as a protective factor against hemorrhagic stroke. Understanding this association and the underlying hemodynamic mechanisms offers valuable guidance for preventive strategies and informs clinical decision-making, improving overall patient care.

Analysis of the role of perfusion parameters in predicting rupture of brain arteriovenous malformations: a multi-center study

This study aimed to investigate the potential correlation between the perfusion parameters of brain arteriovenous malformations (bAVMs) as determined by multiphase CT angiography and bAVM rupture. Based on the occurrence of bAVM-related hemorrhage, 480 diagnosed bAVM patients were divided into hemorrhage (n = 220) and non-hemorrhage (n = 260) groups in this retrospective multi-center study spanning 2010 to 2020. On initial rupture CT images, the bAVM nidus and major draining vein were segmented, and time-density curves were extracted to compute perfusion parameters including mean transit time (MTT), time to peak (TTP), blood volume (BV), and blood flow (BF). To examine the potential correlation between these parameters and bAVM rupture, logistic regression was utilized to analyze multifactorial data and compare differences between the two groups. The ruptured group demonstrated a bAVM nidus characterized by an increased BF, a shorter TTP and MTT, and a higher peak density. The veins that were draining exhibited a reduced TTP, MTT, and peak density. A nidus TTP of less than 4s was identified by the multifactorial analysis as a critical risk factor for bAVM rupture. The statistical results highlight the noteworthy correlation between nidus TTP and bAVM rupture, presenting an original framework for assessing the risk of rupture.

Safety and efficacy of newer liquid embolic agents squid and PHIL in endovascular embolization of cerebral arteriovenous malformations and dural arteriovenous fistulas: A systematic review and meta-analysis

Safety and efficacy of newer liquid embolic agents squid and PHIL in endovascular embolization of cerebral arteriovenous malformations and dural arteriovenous fistulas: A systematic review and meta-analysis

Hypothesizing the interplay of thrombus formation, wall enhancement, and perifocal edema as predictive factors for rupture in brain AVMs

The presence of shear stress within intracranial AVMs (arteriovenous malformations) due to high flow, perinidal angiogenesis, intranidal aneurysms, and biological factors are presumed risk factors for rupture. However, emerging imaging and histological evidence suggests that risk factors for AVM rupture may extend beyond the classical understanding. The presence of perifocal edema at the time of rupture, luminal thrombosis, and vessel wall enhancement on vessel wall MRI elucidate the possibility of an underlying inflammatory process within AVMs, which may predispose them to instability and eventual rupture. We hypothesize that for some AVM ruptures, the occurrence of thrombosis within vascular outpouchings of the AVM initiates a cascade of events, including local hypoxia, inflammation, breakdown of the blood–brain barrier and wall matrix degradation, which is evident from the presence of perifocal edema and vessel wall enhancement observed on imaging. These changes might ultimately raise the risk of AVM rupture and subsequent hemorrhage. Understanding this inflammatory component offers promising insights into AVM pathogenesis and may facilitate the development of preventive strategies to mitigate rupture risk.

Pediatric Cranial Stereotactic Radiosurgery: Meta-Analysis and International Stereotactic Radiosurgery Society Practice Guidelines.

There are limited data on the use of stereotactic radiosurgery (SRS) for pediatric patients. The aim of this systematic review was to summarize indications and outcomes specific to pediatric cranial SRS to inform consensus guidelines on behalf of the International Stereotactic Radiosurgery Society (ISRS). A systematic review, using the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), analyzed English-language articles on SRS, published between 1989 and 2021, that included outcomes for at least 5 pediatric patients. MEDLINE database terms included tumor types and locations, and radiosurgical and age-specific terms. We excluded nonclinical reports, expert opinions, commentaries, and review articles. Meta-regressions for associations with local control were performed for medulloblastoma, craniopharyngioma, ependymoma, glioma, and arteriovenous malformation (AVM). Of the 113 articles identified for review, 68 met the inclusion criteria. These articles described approximately 400 pediatric patients with benign and malignant brain tumors and 5119 with AVMs who underwent cranial SRS. The rates of local control for benign tumors, malignant tumors, and AVMs were 89% (95% CI, 82%-95%), 71% (95% CI, 59%-82%), and 65% (95% CI, 60%-69%), respectively. No significant associations were identified for local control with patient-, tumor-, or treatment-related variables. This review is the first to summarize outcomes specific to SRS for pediatric brain tumors and AVMs. Although data reporting is limited for pediatric patients, SRS appears to provide acceptable rates of local control. We present ISRS consensus guidelines to inform the judicious use of cranial SRS for pediatric patients.

Headache and Visual Aura Outcomes After Stereotactic Radiosurgery for Patients With Occipital Lobe Arteriovenous Malformations: A Single-Center Retrospective Cohort Study.

Patients with brain arteriovenous malformations (BAVMs) sometimes experience migraine-like chronic headaches. Reportedly, this symptom is common in occipital lobe BAVMs; however, the exact prevalence has not been clarified, and the details of visual auras have been scarcely reported. Furthermore, no comprehensive studies exist on the improvement of migraine associated with visual auras in occipital lobe BAVMs after stereotactic radiosurgery (SRS). Therefore, this study investigated the prevalence of headache with visual aura in patients with occipital lobe BAVMs and evaluated the impact of SRS on preexisting symptoms. As a single-center retrospective cohort study, a total of 104 patients with occipital lobe BAVMs treated with SRS from 1990 to 2024 were analyzed. Pre-SRS and post-SRS symptoms of headache and visual aura were documented. The outcomes measured were headache severity, frequency, aura characteristics, and BAVM obliteration rates. Of the 104 patients, 41 (39%) reported chronic headache pre-SRS, and 37 (36%) experienced migraine with visual aura. Compared with pre-SRS, 90% (28/31) of the patients experienced a >50% reduction in headache severity and frequency at a median follow-up of 11 months, and 89% (25/28) experienced a >50% reduction in aura frequency. Complete headache remission was achieved in 35% (13/31) of patients. Complete obliteration of BAVMs was confirmed in 75% (76/102) of the patients at a median of 33 months. A smaller nidus volume was associated with both complete headache remission and BAVM obliteration, whereas age and sex were not significant predictors of headache outcome. Patients with occipital lobe BAVMs frequently experience migraine-like headaches with visual aura, which may be more prevalent than in the general population. SRS for occipital lobe BAVMs could not only achieve favorable BAVM obliteration with minimal adverse effects but also significantly improve migraine-like symptoms, including visual aura, particularly in patients with smaller nidus volumes.

Reporting of angiographic studies in patients diagnosed with a cerebral arteriovenous malformation: a systematic review

A cerebral arteriovenous malformation (cAVM) is an abnormal tangle of cerebral blood vessels. The consensus document by the Joint Writing Group (JWG) highlighted which cAVM features should be recorded. Subsequent publications have reported cAVM angioarchitecture, but it is unknown if all followed the JWG recommendations. The aim of this systematic review was to describe use of the JWG guidelines. A database search, using the PRISMA checklist, was performed. We describe the proportion of publications that used JWG reporting standards, which standards were used, whether the definitions used differed from the JWG, or if any additional angiographic features were reported. Out of 4306 articles identified, 105 were selected, and a further 114 from other sources. Thirty-three studies (33/219; 15%) specifically referred to using JWG standards. Since the JWG publication, few studies have used their standards to report cAVMs. This implies that the angioarchitecture of cAVMs are not routinely fully described.

DSA Quantitative Analysis and Predictive Modeling of Obliteration in Cerebral AVM following Stereotactic Radiosurgery.

Stereotactic radiosurgery is a key treatment modality for cerebral AVMs, particularly for small lesions and those located in eloquent brain regions. Predicting obliteration remains challenging due to evolving treatment paradigms and complex AVM presentations. With digital subtraction angiography (DSA) being the gold standard for outcome evaluation, radiomic approaches offer potential for more objective and detailed analysis. We aimed to develop machine learning modeling using DSA quantitative features for post-SRS obliteration prediction. A prospective registry of patients with cerebral AVMs was screened to include patients with digital prestereotactic radiosurgery DSA. Anterior-posterior and lateral views were retrieved and manually segmented. Quantitative features were computed from the lesion ROI. Following feature selection, machine learning models were developed to predict unsuccessful 2-year total obliteration using processed radiomics features in comparison with clinical and radiosurgical features. When we evaluated through area under the receiver operating characteristic curve (AUROC), accuracy, area under the precision-recall curve F1, recall, and precision, the best performing model predictions on the test set were interpreted using the Shapley additive explanations approach. DSA images of 100 included patients were retrieved and analyzed. The best-performing clinical radiosurgical model was a gradient boosting classifier with an AUROC of 68% and a recall of 67%. When we used radiomics variables as input, the AdaBoost classifier had the best evaluation metrics with an AUROC of 79% and a recall of 75%. The most important clinico-radiosurgical features, ranked by model contribution, were lesion volume, patient age, treatment dose rate, the presence of seizure at presentation, and prior resection. The most important ranked radiomics features were the following: gray-level size zone matrix, gray-level nonuniformity, kurtosis, sphericity, skewness, and gray-level dependence matrix dependence nonuniformity. The combination of radiomics with machine learning is a promising approach for predicting cerebral AVM obliteration status following stereotactic radiosurgery. DSA could enhance prognostication of stereotactic radiosurgery-treated AVMs due to its high spatial resolution. Model interpretation is essential for building transparent models and establishing clinically valid radiomic signatures.

Commentary on Mosaic Copy Number Variation in a Patient with Cerebral and Pulmonary Arteriovenous Malformations and Recurrent Epistaxis.

Commentary on Mosaic Copy Number Variation in a Patient with Cerebral and Pulmonary Arteriovenous Malformations and Recurrent Epistaxis.

Mosaic Copy Number Variation in a Patient with Cerebral and Pulmonary Arteriovenous Malformations and Recurrent Epistaxis.

Mosaic Copy Number Variation in a Patient with Cerebral and Pulmonary Arteriovenous Malformations and Recurrent Epistaxis.

Comparison of a Novel Liquid Embolic System with Commonly Used Embolic Agents in the Endovascular Treatment of Intracranial Dural Arteriovenous Fistulas: A Single-Center Experience

Background/Objectives: Endovascular embolization is an effective treatment option for cerebral arteriovenous malformation (AVM) and dural arteriovenous fistulas (DAVFs). The objective of this study was to assess the safety and efficacy of MenoxTM in patients with cranial dural arteriovenous fistulas. Methods: From January 2021 to January 2023, 19 patients with intracranial DAVFs underwent embolization procedures. All patients were treated by embolization with MenoxTM or/and in combination with other embolization products such as Onyx (Covidien, Irvine, California), PHIL (MicroVention, Tustin, California), and Squid (Balt Extrusion, Montmorency, France). Treatment approaches were selected depending on the anatomical location of the fistula. Patients were monitored and followed-up for 12 months. Results: The patients’ mean age was 56.26 ± 16.49 years. Of these 19 patients, 58% (n = 11) were treated with the MenoxTM liquid embolizing agent (LEA) alone or in combination with different LEAs, while n = 7 were treated with other LEAs and 1 patient was treated solely with coils. Complete occlusion of DAVFs with MenoxTM and other agents was evident in 68.4% (n = 13/19) of patients. Complete occlusion (100%) was observed in the sinus rectus, transverse sinus, and diploic veins of the orbital roof, while complete occlusion was observed in 50% of falcotentorial patients and 60% of superior sagittal sinus patients. The lowest rate of complete fistula obliteration was observed in the dural carotid cavernous fistula (CCF) group (25%). An intra-procedural adverse event occurred in one patient. No other post-procedural adverse events were noted. Furthermore, in patients treated with MenoxTM, total occlusion was achieved in 72.7% (n = 8) of patients, whereas the non-MenoxTM group had 62.5% (n = 5) of patients with 100% occlusion and 37.5% (n = 3) of patients with subtotal occlusion. Conclusions: Outcomes using MenoxTM alone and in combination with other agents were effective, and it is safe for the treatment of dural arteriovenous fistulas.

Natural history and management outcomes of patients with ruptured Spetzler-Martin grade IV and V brain arteriovenous malformations.

The natural history of ruptured high Spetzler-Martin grade IV and V brain arteriovenous malformations (bAVMs) is underreported given the scarcity of this pathology, and decision-making for patients with bAVMs remains unclarified. In this study, the authors sought to shed light on this topic. Patients harboring ruptured high-grade bAVMs were identified from an institutional database spanning from 1990 to 2020. The authors examined outcomes of annual hemorrhagic risk in natural history and after treatment, follow-up hemorrhage rate, bAVM obliteration, follow-up modified Rankin Scale (mRS) score > 2, worsened mRS score, and mortality. After reviewing the charts of 1066 patients without hereditary hemorrhagic telangiectasia, 84 patients with ruptured high-grade bAVMs were included in the study for analysis. For cortical bAVMs, the annual risk of hemorrhage during natural history was 2.68%. Surgery decreased the risk to 0.74%, while radiosurgery increased the risk to 5.35%, and embolization only increased the risk to 16.96%. For deep-seated high-grade bAVMs, the annual risk of hemorrhage during natural history was 8.37%. Radiosurgery decreased the risk to 3.11%, surgery decreased the risk to 5.25%, and embolization only increased the risk to 22.33%. Poisson regression analysis demonstrated that embolization only increased the risk of hemorrhage in cortical bAVMs (rate ratio 4.745, 95% CI 1.365-12.819; p = 0.005) and deep-seated bAVMs (rate ratio 6.290, 95% CI 0.997-21.932; p = 0.013). Logistic regression analysis showed that surgery (OR 52.000, 95% CI 8.083-1046.127; p = 0.004) and radiosurgery (OR 11.142, 95% CI 1.804-217.650; p = 0.029) were predictors of obliteration in cortical and deep-seated bAVMs, respectively. The proportions of patients experiencing a worsened mRS score, a follow-up mRS score > 2, and mortality were similar between conservative and treatment groups. The natural history of cortical ruptured high-grade bAVMs bears a risk similar to that of incidental bAVMs, whereas deep-seated ruptured high-grade bAVMs have an increased risk of hemorrhage. With extremely prudent patient selection, surgery might be a viable option for cortical bAVMs to obliterate the bAVM and reduce hemorrhagic risk, while preserving functional status. Radiosurgery might be beneficial to lower hemorrhagic risk in deep-seated bAVMs. Embolization as a single modality should be avoided as it provides no benefit to reduce hemorrhagic risk.

Conservative management of brain arteriovenous malformations: results of the prospective observation registry of a pragmatic trial.

Many patients recruited in the Treatment of Brain Arteriovenous Malformations Study (TOBAS) are managed conservatively. The aim of this study was to monitor what happened to those patients. TOBAS comprises two randomized controlled trials and multiple prospective registries. All patients with brain arteriovenous malformations (AVMs) can participate. This report concerns patients selected for conservative management. The primary trial outcome measure is related death or dependency (modified Rankin Scale [mRS] score > 2) at 10 years. Secondary outcomes include intracranial hemorrhages, nonhemorrhagic neurological events, and serious adverse events (SAEs). For this report, outcome results are presented using patient-years, Kaplan-Meier survival curves, and Cox log-rank tests. There was no blinding. From June 2014 to May 2021, 1010 patients were recruited, of whom 498 (49%) were proposed the prospective observation registry. After exclusions, 434 (87%) patients remained for analysis. The majority of patients had unruptured AVMs (378/434 [87%]), of which 195 (52%) were low grade (Spetzler-Martin grade I or II). During a mean follow-up period of 3.2 years (total 1368 patient-years), the primary outcome occurred in 23 of 434 (5%) patients, corresponding to an incidence of 1.7 (95% CI 1.1-2.5) per 100 patient-years. For unruptured AVMs the incidence was 1.1 (95% CI 0.7-1.9) per 100 patient-years, and for low-grade unruptured AVMs it was 0.6 (95% CI 0.2-1.7) per 100 patient-years. Poor outcomes were more frequent in patients with a history of rupture (HR 5.6 [95% CI 2.4-13.0], p < 0.001), infratentorial AVMs (HR 2.9 [95% CI 1.1-7.3], p = 0.027), and age ≥ 55 years (HR 3.2 [95% CI 1.4-7.6], p = 0.007). Major intracranial hemorrhage occurred in 35 of 434 (8%) patients (incidence of 2.6 [95% CI 1.9-3.6] per 100 patient-years; 2.0 [95% CI 1.3-2.9] per 100 patient-years for unruptured AVMs and 1.3 [95% CI 0.6-2.6] per 100 patient-years for low-grade unruptured AVMs). Major AVM hemorrhages were more frequent in ruptured (HR 4.4 [95% CI 2.1-8.9], p < 0.001), large (HR 2.6 [95% CI 1.1-6.6], p = 0.039), and high-grade (HR 2.5 [95% CI 1.2-5.3], p = 0.013) AVMs and those with deep venous drainage (HR 2.1 [95% CI 1.1-4.2], p = 0.032). SAEs occurred in 48 of 434 (11%) patients (incidence of 3.6 [95% CI 2.7-4.8] per 100 patient-years). For unruptured AVMs the incidence was 2.8 (95% CI 2.0-4.0) per 100 patient-years, and for low-grade unruptured AVMs it was 1.8 (95% CI 1.0-3.2) per 100 patient-years. Nearly half of TOBAS participants were observed. Rates of untoward neurological events were within expected boundaries.

Stereotactic radiosurgery as an alternative treatment for dural arteriovenous fistula

Unlike cerebral arteriovenous malformation or cavernous malformation, dural arteriovenous fistula (DAVF) is an uncommon cerebrovascular malformation in clinical practice. However, the clinical treatment modalities for DAVFs have expanded in recent years. The standard treatment for DAVF is endovascular surgery. Endovascular surgery is an effective and safe treatment method if open surgical treatment is considered dangerous in a patient. Nonetheless, after endovascular embolization, additional treatment is often required due to insecure occlusion or procedure-related sequelae. Recent reports have demonstrated stereotactic radiosurgery (SRS) as an effective and safe alternative to conventional endovascular surgery. This review summarizes DAVF and SRS in general and proposes indications for SRS as an appropriate treatment option for DAVFs.