Reporting terminology for brain arteriovenous malformation clinical and radiographic features for use in clinical trials

Risk Factors for Early Brain AVM Rupture: Cohort Study of Pediatric and Adult Patients

BACKGROUND AND PURPOSE

Whether architectural characteristics of ruptured brain AVMs vary across the life span is unknown. We aimed to identify angioarchitectural features associated with brain AVMs ruptured early in life.

MATERIALS AND METHODS

Patients with ruptured brain AVMs referred to 2 distinct academic centers between 2000 and 2018 were pooled and retrospectively analyzed. Imaging was retrospectively reviewed for angioarchitectural characteristics, including nidus size, location, Spetzler-Martin grade, venous drainage, and arterial or nidal aneurysm. Angioarchitecture variations across age groups were analyzed using uni- and multivariable models; then cohorts were pooled and analyzed using Kaplan-Meier and Cox models to determine factors associated with earlier rupture.

RESULTS

Among 320 included patients, 122 children (mean age, 9.8 ± 3.8 years) and 198 adults (mean age, 43.3 ± 15.7 years) were analyzed. Pediatric brain AVMs were more frequently deeply located (56.3% versus 21.2%, P < .001), with a larger nidus (24.2  versus 18.9 mm, P = .002), were less frequently nidal (15.9% versus 23.5%, P = .03) and arterial aneurysms (2.7% versus 17.9%, P < .001), and had similar drainage patterns or Spetzler-Martin grades. In the fully adjusted Cox model, supratentorial, deep brain AVM locations (adjusted relative risk, 1.19; 95% CI, 1.01-1.41; P = .03 and adjusted relative risk, 1.43; 95% CI, 1.22-1.67; P < .001, respectively) and exclusively deep venous drainage (adjusted relative risk, 1.46, 95% CI, 1.21-1.76; P < .001) were associated with earlier rupture, whereas arterial or nidal aneurysms were associated with rupture later in life.

CONCLUSIONS

The angioarchitecture of ruptured brain AVMs significantly varies across the life span. These distinct features may help to guide treatment decisions for patients with unruptured AVMs.

Interrater Reliability in the Measurement of Flow Characteristics on Color-Coded Quantitative DSA of Brain AVMs

BACKGROUND AND PURPOSE

Hemodynamic features of brain AVMs may portend increased hemorrhage risk. Previous studies have suggested that MTT is shorter in ruptured AVMs as assessed on quantitative color-coded parametric DSA. This study assesses the interrater reliability of MTT measurements obtained using quantitative color-coded DSA.

MATERIALS AND METHODS

Thirty-five color-coded parametric DSA images of 34 brain AVMs were analyzed by 4 neuroradiologists with experience in interventional neuroradiology. Hemodynamic features assessed included MTT of the AVM and TTP of the dominant feeding artery and draining vein. Agreement among the 4 raters was assessed using the intraclass correlation coefficient.

RESULTS

The interrater reliability among the 4 raters was poor (intraclass correlation coefficient = 0.218; 95% CI, 0.062-0.414; P value = .002) as it related to MTT assessment. When the analysis was limited to cases in which the raters selected the same image to analyze and selected the same primary feeding artery and the same primary draining vein, interrater reliability improved to fair (intraclass correlation coefficient  = 0.564; 95% CI, 0.367-0.717; P < .001).

CONCLUSIONS

Interrater reliability in deriving color-coded parametric DSA measurements such as MTT is poor so minor differences among raters may result in a large variance in MTT and TTP results, partly due to the sensitivity and 2D nature of the technique. Reliability can be improved by defining a standard projection, feeding artery, and draining vein for analysis.

Long-term outcomes of brainstem arteriovenous malformations after different management modalities: a single-centre experience

OBJECTIVE

The aims of this study are to clarify the long-term outcomes of brainstem arteriovenous malformations (AVMs) after different management modalities.

METHODS

The authors retrospectively reviewed 61 brainstem AVMs in their institution between 2011 and 2017. The rupture risk was represented by annualised haemorrhagic rate. Patients were divided into five groups: conservation, microsurgery, embolisation, stereotactic radiosurgery (SRS) and embolisation+SRS. Neurofunctional outcomes were evaluated by the modified Rankin Scale (mRS). Subgroup analysis was conducted between different management modalities to compare the long-term outcomes in rupture or unruptured cohorts.

RESULTS

All of 61 brainstem AVMs (12 unruptured and 49 ruptured) were followed up for an average of 4.5 years. The natural annualised rupture risk was 7.3%, and the natural annualised reruptured risk in the ruptured cohort was 8.9%. 13 cases were conservative managed and 48 cases underwent intervention (including 6 microsurgery, 12 embolisation, 21 SRS and 9 embolisation+SRS). In the selection of interventional indication, diffuse nidus were often suggested conservative management (p=0.004) and nidus involving the midbrain were more likely to be recommended for intervention (p=0.034). The risk of subsequent haemorrhage was significantly increased in partial occlusion compared with complete occlusion and conservative management (p<0.001, p=0.036, respectively). In the subgroup analysis, the follow-up mRS scores of different management modalities were similar whether in the rupture cohort (p=0.064) or the unruptured cohort (p=0.391), as well as the haemorrhage-free survival (p=0.145). In the adjusted Bonferroni correction analysis of the ruptured cohort, microsurgery and SRS could significantly improve the obliteration rate compared with conservation (p<0.001, p=0.001, respectively) and SRS may have positive effect on avoiding new-onset neurofunctional deficit compared with microsurgery and embolisation (p=0.003, p=0.003, respectively).

CONCLUSIONS

Intervention has similar neurofunctional outcomes as conservation in these brainstem AVM cohorts. If intervention is adopted, partial obliteration should be avoided because of the high subsequent rupture risk.

TRIAL REGISTRATION NUMBER

NCT04136860.

Contemporary management of brain arteriovenous malformations in mainland China: a web-based nationwide questionnaire survey

BACKGROUND

In the benefit of the large population and rapid economic growth, the interventional techniques and equipment for brain arteriovenous malformations (bAVMs) in mainland China have been rapidly improved. Chinese neurosurgical cerebrovascular physicians have accumulated rich experience and made pioneering explorations. This study aims to summarize the experience and treatment progress of bAVMs in mainland China.

METHODS

We performed a web-based nationwide questionnaire survey among 67 tertiary neurosurgical institutions that had acknowledged treating bAVMs in the primary survey. Our questionnaire included clinical characteristics, radiological findings, intervention indications/contraindications, intervention timing, and intraoperative management of different treatment modalities.

RESULTS

A total of 63 participants from 49 (73.1%) tertiary neurosurgical institutions responded to our questionnaire. Forty-two (66.7%) were neurosurgeons, 13 (20.6%) were neurointerventionists, and 8 (12.7%) were radiosurgeons. Approximately 3500 to 4000 cases of bAVMs were treated annually in these 49 departments. All participants agreed that the conclusions of ARUBA are debatable. Flow-related aneurysms, deep venous drainage, and arteriovenous fistula were considered as common hemorrhagic risk factors. Unruptured SM IV-V bAVMs, giant bAVMs, pediatric bAVMs, elderly bAVMs, and eloquent bAVMs were not absolute contraindications to intervention. Maximum lesion occlusion and minimal functional impairment were the principles of intervention management. Most of the neurosurgeons and neurointerventionists recommended early intervention (< 30 days) for ruptured bAVMs, and the radiosurgeons suggested intervention in the chronic phase or recovery phase (P < 0.01) and preferably 3 months after bleeding. Multi-modality strategies were thought effective for complex bAVMs, and more exploration of individualized intraoperative management was necessary.

CONCLUSIONS

Intervention was acceptable for specific selected unruptured bAVMs in mainland China, especially in patients with hemorrhagic risk factors. The application of multidisciplinary cerebrovascular team and multicenter large-sample international registry study might be the next work for Chinese neurosurgical cerebrovascular physicians.

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.

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.

Long-term outcomes and prognostic predictors of 111 pediatric hemorrhagic cerebral arteriovenous malformations after microsurgical resection: a single-center experience

Comparison in pediatric hemorrhagic arteriovenous malformations (AVMs) to clarify the long-term neurological outcomes and prognostic predictors after surgical intervention was relatively rare, especially in the selection of surgical timing. The objective of this study was to elucidate these points. The authors retrospectively reviewed the pediatric hemorrhagic AVMs resected in their neurosurgical department between March 2010 and June 2017. The natural history was represented by rupture risk. Neurological outcome was assessed with the modified Rankin Scale (mRS) for children. Multivariate logistic regression analyses were used to assess the risk factors for disability (mRS > 2). The hemorrhagic early phase was defined as less than 30 days after bleeding. The corresponding prognosis of different surgical timing (early intervention or delayed intervention) was compared after propensity-score matching (PSM). A total of 111 pediatric hemorrhagic AVM patients were evaluated. The average patient age was 11.1 ± 4.0 years, with a mean follow-up of 4.3 ± 2.1 years. The annualized rupture risk was 9.3% for the pediatric hemorrhagic AVMs, and the annualized re-rupture risk was 9.8%. 7.2% of the patients had disabilities (mRS > 2) and 82.0% achieved neurological deficit-free (mRS < 2) at the last follow-up. Pre-treatment mRS (P = 0.042) and flow-related aneurysms (P = 0.039) were independent factors for long-term disability. In terms of short-term outcomes, early intervention was better than delayed intervention (P = 0.033), but the long-term outcomes were similar between the two groups (P = 0.367). Surgical intervention for pediatric hemorrhagic AVMs is recommended, most of the patients can achieve good neurological outcomes. Moreover, early surgical intervention is preferred after the initial hemorrhage.

Stagnant Venous Outflow Predicts Brain Arteriovenous Malformation Obliteration After Gamma Knife Radiosurgery Without Prior Intervention

BACKGROUND

Gamma Knife radiosurgery (GKRS) obliterates 65% to 82% of brain arteriovenous malformations (BAVMs).

OBJECTIVE

To explore the impact of hemodynamics on GKRS outcomes.

METHODS

We retrospectively (2011-2017) included 98 patients with BAVMs who had received GKRS alone. Two evaluators, blinded to the outcomes, analyzed the pre-GKRS angiography and magnetic resonance images to obtain the morphological characteristics and quantitative digital subtraction angiography (QDSA) parameters. The venous stasis index was defined as the inflow gradient divided by the absolute value of the outflow gradient. Patients’ follow-up magnetic resonance or digital subtraction angiography images were evaluated for the presence of complete obliteration (CO). Cox regression and Kaplan–Meier analyses were conducted to determine the correlations between the parameters and outcomes.

RESULTS

Among the 98 patients, 63 (63.4%) achieved CO after GKRS at a median latency period of 31 mo. In multivariable analyses with adjustments for age and sex, increased BAVM volume (hazard ratio (HR) 0.949, P = .022) was an independent characteristic predictor, and venous stenosis (HR 2.595, P = .009), venous rerouting (HR 0.375, P = .022), and larger stasis index (HR 1.227, P = .025) were independent angiographic predictors of CO. BAVMs with a stasis index of &gt;1.71 had a higher 36-mo probability of CO than those with a stasis index of ≤1.71 (61.1% vs 26.7%, P &lt; .001).

CONCLUSION

BAVMs with a larger stasis index, indicating more stagnant venous outflow, may predict obliteration after GKRS. QDSA analysis may help in predicting BAVM treatment outcomes and making therapeutic decisions.

Interventions for treating brain arteriovenous malformations in adults

BACKGROUND

Brain arteriovenous malformations (AVMs) are the single most common cause of intracerebral haemorrhage in young adults. Brain AVMs also cause seizure(s) and focal neurological deficits (in the absence of haemorrhage, migraine or an epileptic seizure); approximately one-fifth are incidental discoveries. Various interventions are used in an attempt to eradicate brain AVMs: neurosurgical excision, stereotactic radiosurgery, endovascular embolization, and staged combinations of these interventions. This is an update of a Cochrane Review first published in 2006, and last updated in 2009.

OBJECTIVES

To determine the effectiveness and safety of the different interventions, alone or in combination, for treating brain AVMs in adults compared against either each other, or conservative management, in randomized controlled trials (RCTs).

SEARCH METHODS

The Cochrane Stroke Group Information Specialist searched the Cochrane Stroke Group Trials Register (last searched 7 January 2019), the Cochrane Central Register of Controlled Trials (CENTRAL; 2019, Issue 1) in the Cochrane Library, MEDLINE Ovid (1980 to 14 January 2019), and Embase OVID (1980 to 14 January 2019). We searched international registers of clinical trials, the contents pages of relevant journals, and bibliographies of relevant articles (November 2009). We also contacted manufacturers of interventional treatments for brain AVMs (March 2005).

SELECTION CRITERIA

We sought RCTs of any intervention for brain AVMs (used alone or in combination), compared against each other or against conservative management, with relevant clinical outcome measures.

DATA COLLECTION AND ANALYSIS

One author screened the results of the updated searches for potentially eligible RCTs for this updated review. Both authors independently read the potentially eligible RCTs in full and confirmed their inclusion according to the inclusion criteria. We resolved disagreement by discussion. We assessed the risk of bias in included studies and applied GRADE.

MAIN RESULTS

We included one trial with 226 participants: A Randomized trial of Unruptured Brain Arteriovenous Malformations (ARUBA), comparing intervention versus conservative management for unruptured brain AVMs (that had never bled). The quality of evidence was moderate because we found just one trial that was at low risk of bias other than a high risk of performance bias due to participants and treating physicians not being blinded to allocated treatment. Data on functional outcome and death at a follow-up of 12 months were provided for 218 (96%) of the participants in ARUBA. In this randomized controlled trial (RCT), intervention compared to conservative management increased death or dependency (modified Rankin Scale score ≥ 2, risk ratio (RR) 2.53, 95% confidence interval (CI) 1.28 to 4.98; 1 trial, 226 participants; moderate-quality evidence) and the proportion of participants with symptomatic intracranial haemorrhage (RR 6.75, 95% CI 2.07 to 21.96; 1 trial, 226 participants; moderate-quality evidence), but there was no difference in the frequency of epileptic seizures (RR 1.14, 95% CI 0.63 to 2.06; 1 trial, 226 participants; moderate-quality evidence). Three RCTs are ongoing.

AUTHORS' CONCLUSIONS

We found moderate-quality evidence from one RCT including adults with unruptured brain AVMs that conservative management was superior to intervention with respect to functional outcome and symptomatic intracranial haemorrhage over one year after randomization. More RCTs will help to confirm or refute these findings.

Interval angioarchitectural evolution of brain arteriovenous malformations following rupture

OBJECTIVE

The goal of this study was to describe changes in the angioarchitecture of brain arteriovenous malformations (bAVMs) between acute and delayed cerebral digital subtraction angiography (DSA) obtained after hemorrhage, and to examine bAVM characteristics predicting change.

METHODS

This is a retrospective study of a prospective institutional bAVM database. The authors included all patients with ruptured bAVMs who had DSA in both acute and delayed phases, with no interval treatment of their bAVM, between January 2000 and April 2017. The authors evaluated the existence or absence of angioarchitectural changes. Demographic data, radiological characteristics of hemorrhages, and angioarchitectural features of the bAVMs of the two patients' groups were analyzed. Univariate and multivariate logistic analyses were performed to identify predictors of angioarchitectural change.

RESULTS

A total of 42 patients were included in the series. Seventeen (40.5%) patients had angioarchitectural changes including bAVM only visible on the delayed DSA study (n = 8), spontaneous thrombosis of the AVM (n = 3), or alteration of the size or the opacification of the nidus (n = 6). The factors associated with angioarchitectural changes were a small nidus (3.8 ± 7.9 ml vs 6.1 ± 9.5 ml, p = 0.046), a superficial location (94.1% vs 5.9%, p = 0.016), and a single superficial draining vein (58.8% vs 24.0%, p = 0.029).

CONCLUSIONS

Angioarchitectural changes can be seen in 40% of ruptured bAVMs between the acute- and delayed-phase DSA. A small nidus, a superficial location, and a single superficial draining vein were statistically associated with the occurrence of angioarchitectural changes. These changes included either enlargement or spontaneous occlusion of the bAVM, as well as subsequent diagnosis of a bAVM following an initial negative DSA study.

R2eD AVM Score

Background and Purpose- The management of unruptured brain arteriovenous malformations remains unclear. Using a large cohort to determine risk factors predictive of hemorrhagic presentation of arteriovenous malformations, this study aims to develop a predictive tool that could guide hemorrhage risk stratification. Methods- A database of 789 arteriovenous malformation patients presenting to our institution between 1990 and 2017 was used. A hold-out method of model validation was used, whereby the data was randomly split in half into training and validation data sets. Factors significant at the univariable level in the training data set were used to construct a model based on multivariable logistic regression. Model performance was assessed using receiver operating curves on the training, validation, and complete data sets. The predictors and the complete data set were then used to derive a risk prediction formula and a practical scoring system, where every risk factor was worth 1 point except race, which was worth 2 points (total score varies from 0 to 6). The factors are summarized by R₂eD arteriovenous malformation (acronym: R₂eD AVM). Results- In 755 patients with complete data, 272 (36%) presented with hemorrhage. From the training data set, a model was derived containing the following risk factors: nonwhite race (odds ratio [OR]=1.8; P=0.02), small nidus size (OR=1.47; P=0.14), deep location (OR=2.3; P<0.01), single arterial feeder (OR=2.24; P<0.01), and exclusive deep venous drainage (OR=2.07; P=0.02). Area under the curve from receiver operating curve analysis was 0.702, 0.698, and 0.685 for the training, validation, and complete data sets, respectively. In the entire study population, the predicted probability of hemorrhagic presentation increased in a stepwise manner from 16% for patients with no risk factors (score of 0) to 78% for patients having all the risk factors (score of 6). Conclusions- The final model derived from this study can be used as a predictive tool that supplements clinical judgment and aids in patient counseling.

Venous Stenosis and Hemorrhage After Radiosurgery for Cerebral Arteriovenous Malformations

BACKGROUND

The risk of hemorrhage remains after radiosurgery for patients with arteriovenous malformations (AVMs), especially during the latency period. The effect of venous outflow stenosis on postradiosurgery AVM hemorrhage has been understudied. The present study sought to clarify the effect of venous stenosis on postradiation hemorrhage.

METHODS

We retrospectively reviewed the records of patients with AVM seen at our institution from 1990 to 2015. Patients who had undergone radiosurgery were included, and those without sufficient data were excluded. We performed multivariable Cox regression to evaluate the predictors of postradiosurgery hemorrhage, with specific emphasis on venous stenosis. Patients were censored from the first radiosurgery to hemorrhage or the last follow-up visit. The baseline and angiographic characteristics were compared between those with venous stenosis and those without to address potential confounders.

RESULTS

The present study included 240 patients, of whom 29 (12.1%) had venous stenosis. The venous stenosis cohort included more patients with venous varices (P = 0.009) and fewer with deep venous drainage (P = 0.048) compared with those without venous stenosis. Most patients had grade III or higher AVMs (63.2%), with an obliteration rate of 32.9%. In an all-inclusive multivariable Cox regression, hemorrhage risk was associated with venous stenosis (hazard ratio [HR], 3.70; P = 0.034), age (HR, 1.05; P = 0.002), AVM volume (HR, 1.04; P = 0.004), and hemorrhage before treatment (HR, 4.11; P = 0.014). Male gender was protective (HR, 0.31; P = 0.036) against hemorrhage.

CONCLUSIONS

We identified statistically significant risk factors for postradiosurgery AVM hemorrhage, which included advanced age, female gender, the presence of venous stenosis, a larger AVM volume, and previous hemorrhage. We recommend cautious selection of patients for radiosurgery with close follow-up after treatment, especially for patients with these risk factors.

Fully automated tissue segmentation of the prescription isodose region delineated through the Gamma knife plan for cerebral arteriovenous malformation (AVM) using fuzzy C-means (FCM) clustering

Background

Gamma knife radiosurgery (GKRS) is a common treatment for cerebral arterio-venous malformations (AVMs), particularly in cases where the malformation is deep-seated, large, or in eloquent areas of the brain. Unfortunately, these procedures can result in radiation injury to brain parenchyma. The fact that every AVM is unique in its vascular morphology makes it nearly impossible to exclude brain parenchyma from isodose radiation exposure during the formulation of a GKRS plan. Calculating the percentages of the various forms of tissue exposed to specific doses of radiation is crucial to understanding the clinical responses and causes of brain parenchyma injury following GKRS for AVM.

Methods

In this study, we developed a fully automated algorithm using unsupervised classification via fuzzy c-means clustering for the analysis of T2 weighted images used in a Gamma knife plan. This algorithm is able to calculate the percentages of nidus, brain tissue, and cerebrospinal fluid (CSF) within the prescription isodose radiation exposure region.

Results

The proposed algorithm was used to assess the treatment plan of 25 patients with AVM who had undergone GKRS. The Dice similarity index (SI) was used to determine the degree of agreement between the results obtained using the algorithm and a visually guided manual method (the gold standard) performed by an experienced neurosurgeon. In the nidus, the SI was (74.86 ± 1.30%) (mean ± standard deviation), the sensitivity was (83.05 ± 11.91)%, and the specificity was (86.73 ± 10.31)%. In brain tissue, the SI was (79.50 ± 6.01)%, the sensitivity was (73.05 ± 9.77)%, and the specificity was (85.53 ± 7.13)%. In the CSF, the SI was (69.57 ± 15.26)%, the sensitivity was (89.86 ± 5.87)%, and the specificity was (92.36 ± 4.35)%.

Conclusions

The proposed clustering algorithm provides precise percentages of the various types of tissue within the prescription isodose region in the T2 weighted images used in the GKRS plan for AVM. Our results shed light on the causes of brain radiation injury after GKRS for AVM. In the future, this system could be used to improve outcomes and avoid complications associated with GKRS treatment.

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A novel image analytical method for the analysis of images of an AVM in a GKRS plan

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Fuzzy c-means clustering was used for analyses of T2w images in the GKRS plan.

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Automatic calculation of percentages of tissue inside the isodose line

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Brain tissue percentages of the nidus of the AVM predict risk of complication.

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Proposed method could be used to avoid complications associated after GKRS.

Transdural Blood Supply in Cerebral Arteriovenous Malformations: A Systematic Evaluation of Angioarchitecture

BACKGROUND AND PURPOSE

Arterial transdural blood supply is a rare angiographic phenomenon in cerebral AVMs. This study aimed to evaluate angiographic transdural blood supply characteristics and to describe the clinical peculiarities of these lesions.

MATERIALS AND METHODS

A prospective AVM data base of 535 patients, enrolled from 1990 to 2016, was analyzed retrospectively. Clinical information was reviewed through patients' medical charts and radiologic studies. Patients with previous AVM treatment were excluded (n = 28).

RESULTS

Patients with (n = 32, male/female ratio = 10:22; mean age, 46 ± 15 years; range, 13-75 years) and without transdural blood supply (n = 475, male/female ratio = 260:215; mean age, 40 ± 18 years; range, 2-87 years) did not show significant differences in clinical presentation (age, hemorrhage, seizures, chronic headache). The predominant nidus size in patients with transdural blood supply was ≥30 mm, with significantly more patients with large AVMs (>60 mm, P = .001). To describe the transdural blood supply, we used 3 grades based on the angiographic transdural blood supply proportion and intensity of AVM nidus perfusion (I-III). Fifty-seven percent of patients with chronic headache had a strong and substantial transdural nidus perfusion (III) and a high-flow transdural blood supply.

CONCLUSIONS

Cerebral AVMs with transdural blood supply represent a rare and heterogeneous subgroup. Lesions can be graded by quantifying the transdural blood supply of the nidus and by capturing hemodynamic characteristics. The broad spread of angiographic features and comparable clinical patterns of patients with or without transdural blood supply raises questions about the relevance of the transdural blood supply to the natural history risk of an AVM and the intention for treatment.

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.

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.

Deep Sequencing of Small RNAs in Blood of Patients with Brain Arteriovenous Malformations

BACKGROUND

Deregulation of circulating microRNAs (miRNAs) is always associated with development and progression of human diseases. We aimed to assess whether patients with brain arteriovenous malformations (BAVMs) possess a distinct miRNA signature compared with healthy subjects.

METHODS

Three patients with unruptured BAVMs and 3 normal control subjects were recruited as case and control groups. Peripheral blood was collected, and miRNA signature was obtained by next-generation sequencing, followed by comparative, functional, and network analyses. Quantitative reverse transcription polymerase chain reaction was performed to validate expression of specific miRNAs.

RESULTS

Deep sequencing detected 246 differentially expressed miRNAs in blood samples of patients with BAVMs compared with normal control subjects. For the top 5 miRNAs, 946 target genes were predicted, and a BAVM-specific miRNA-target gene regulatory network was constructed. Functional annotation suggested that 15 of the predicted miRNA-targeted genes were involved in vascular endothelial growth factor signaling, in which 3 critical miRNAs were involved: miR-7-5p, miR-199a-5p, and miR-200b-3p.

CONCLUSIONS

We explored the miRNA expression signature of BAVMs, which will provide an important foundation for future studies on the regulation of miRNAs involved in BAVMs.

Predictors of intracranial hemorrhage volume and distribution in brain arteriovenous malformation

Background and purpose Despite evidence regarding risk factors for brain arteriovenous malformation (bAVM)-associated spontaneous intracranial hemorrhage (ICH), few data exist describing the spectrum of clinical outcomes that bAVM-associated ICH may manifest. This study aimed to identify the demographical, clinical, and bAVM anatomical variables associated with ICH volume and the presence of intraventricular hemorrhage (IVH) of ruptured bAVMs, two indicators of worse clinical outcome, to help better predict outcome for unruptured bAVMs. Methods Computed tomography images ( n = 169) of patients with ruptured bAVM in a prospectively maintained institutional database were retrospectively reviewed to calculate ICH volume and the presence or absence of IVH. Demographic, clinical, and bAVM characteristics information was summarized and analyzed with univariable and multivariable regression models to identify the associations of these features with ICH volume and the presence of IVH. Results Patient sex, exclusively deep venous drainage, and lobar location were associated with ICH volume in univariable analysis; exclusively deep venous drainage remained significant in multivariable analysis (PI = 0.33, 95% CI: 0.21-0.52, p < 0.001). Exclusively deep venous drainage, multiple feeding arteries, and venous stenosis were associated with IVH in univariable analysis; exclusively deep venous drainage (OR = 7.27, 95% CI: 1.94-27.29, p = 0.003) remained significant in multivariable analysis. Conclusions Variables associated with ICH volume and the presence of IVH in ruptured bAVMs were evaluated and identified. They impart information that may help predict the clinical outcome of unruptured bAVM, in turn aiding clinicians in treatment planning.

Cerebral arteriovenous malformation draining vein stenosis is associated with atherosclerotic risk factors

OBJECTIVE

The pathogenesis of venous outflow stenosis associated with cerebral arteriovenous malformation (AVM) draining veins is poorly understood. We sought to determine the relationship between venous stenosis and atherosclerotic risk factors.

MATERIALS AND METHODS

All patients with an AVM seen at our institution between 1990 and 2016 were retrospectively reviewed. Patients <18 years of age were excluded. Patients were classified into two groups based on the presence or absence of venous stenosis. Patient charts were reviewed for the following atherosclerotic risk factors: age >50 years, sex, race, hypertension, type 2 diabetes mellitus, hyperlipidemia, coronary artery disease, chronic kidney disease stage III, and cigarette smoking. The relationship between venous stenosis and atherosclerotic risk factors was assessed using univariate and multivariate analyses.

RESULTS

278 patients were included (mean age 41 years, 55% men). Venous stenosis was present in 87 patients (31% of the cohort). The presence of venous stenosis was significantly associated with age >50 years (P=0.05), hypertension (P=0.05), diabetes (P=0.02), and hyperlipidemia (P=0.001). Multivariate analysis showed that hyperlipidemia (P=0.05) was predictive of draining vein stenosis.

CONCLUSIONS

Venous stenosis is associated with several atherosclerotic risk factors, suggesting that cerebral AVM venous outflow stenosis occurs by a degenerative process. Additional studies can show whether these modifiable risk factors may be targeted to prevent draining vein stenosis and AVM rupture.

Early Rebleeding after Brain Arteriovenous Malformation Rupture, Clinical Impact and Predictive Factors: A Monocentric Retrospective Cohort Study

Background: Brain arteriovenous malformations (BAVMs) are a leading cause of intracranial hemorrhage in young adults. This study aimed to identify individual predictive factors of early rebleeding after BAVM rupture and determine its impact on prognosis. Methods: Early rebleeding was defined as a spontaneous intracranial hemorrhage within 30 days of BAVM rupture in patients with nonobliterated BAVMs. One hundred fifty one patients with 158 BAVM hemorrhagic events admitted to a tertiary care center during 14 years were included. Univariate followed by multivariate logistic regression was performed to assess the impact of early rebleeding on in-hospital mortality and modified Rankin Scale (mRS) score beyond 3 months and to identify independent predictors of early rebleeding. Results: Eight early rebleeding events were observed, 6 of which occurred during the first 7 days. Early rebleeding was independently and significantly associated with poor outcome (mRS ≥3 beyond 3 months, p = 0.004) but not with in-hospital mortality (p = 0.9). Distal flow-related aneurysms (p = 0.009) and altered consciousness with a Glasgow coma scale score of 3 (p = 0.01) were independently associated with early rebleeding. Conclusions: Early rebleeding is a severe complication that can occur after BAVM-related hemorrhage. Distal flow-related aneurysms and initial altered consciousness are associated with early rebleeding.

Pial Artery Supply as an Anatomic Risk Factor for Ischemic Stroke in the Treatment of Intracranial Dural Arteriovenous Fistulas

BACKGROUND AND PURPOSE

Although intracranial dural arteriovenous fistulas are principally supplied by dural branches of the external carotid, internal carotid, and vertebral arteries, they can also be fed by pial arteries that supply the brain. We sought to determine the frequency of neurologic deficits following treatment of intracranial dural arteriovenous fistulas with and without pial artery supply.

MATERIALS AND METHODS

One hundred twenty-two consecutive patients who underwent treatment for intracranial dural arteriovenous fistulas at our hospital from 2008 to 2015 were retrospectively reviewed. Patient data were examined for posttreatment neurologic deficits; patients with such deficits were evaluated for imaging evidence of cerebral infarction. Data were analyzed with multivariable logistic regression.

RESULTS

Of 122 treated patients, 29 (23.8%) had dural arteriovenous fistulas with pial artery supply and 93 (76.2%) had dural arteriovenous fistulas without pial arterial supply. Of patients with pial artery supply, 4 (13.8%) had posttreatment neurologic deficits, compared with 2 patients (2.2%) without pial artery supply (P = .04). Imaging confirmed that 3 patients with pial artery supply (10.3%) had cerebral infarcts, compared with only 1 patient without pial artery supply (1.1%, P = .03). Increasing patient age was also positively associated with pial supply and treatment-related complications.

CONCLUSIONS

Patients with dural arteriovenous fistulas supplied by the pial arteries were more likely to experience posttreatment complications, including ischemic strokes, than patients with no pial artery supply. The approach to dural arteriovenous fistula treatment should be made on a case-by-case basis so that the risk of complications can be minimized.

Higher Flow Is Present in Unruptured Arteriovenous Malformations With Silent Intralesional Microhemorrhages

BACKGROUND AND PURPOSE

Silent microhemorrhage (hemosiderin) has been observed in resected brain arteriovenous malformations (bAVM) tissue and may represent a subgroup at increased risk for clinical hemorrhage. Previous studies suggest that ruptured bAVMs have faster flow and shorter mean transit time of contrast in blood vessels than unruptured bAVMs. We hypothesized that flow would be faster in unruptured AVMs with hemosiderin compared with those without hemosiderin.

METHODS

We selected unruptured, supratentorial bAVMs >3.5 cc with pathology specimens. Hemodynamic features were evaluated using color-coding angiography, including contrast mean transit time of AVM nidus, time to peak (TTP) of feeding artery (FA) and draining vein (DV), and the ratio (TTP DV/FA). Characteristics of 9 cases with hemosiderin and 16 without hemosiderin were compared using 2-sample t tests and Fisher exact tests.

RESULTS

No difference in FA TTP and DV TTP was observed between groups. However, cases with hemosiderin had significantly shorter mean transit time compared with those without hemosiderin (1.11±0.28 versus 1.64±0.55 seconds; P=0.013) and a lower ratio of DV TTP/FA TTP (1.48±0.32 versus 1.94±0.61; P=0.045). Presence of venous varix was significantly associated with hemosiderin (P=0.003). No other clinical or angioarchitectural factors were associated with hemosiderin.

CONCLUSIONS

Shorter mean transit time through the AVM nidus, lower DV TTP/FA TTP, and the high prevalence of venous varices suggests that high flow is an important feature of unruptured bAVMs with hemosiderin.

Comparison of Grading Scales Regarding Perioperative Complications and Clinical Outcomes of Brain Arteriovenous Malformations After Endovascular Therapy-Multicenter Study

OBJECTIVES

Several scales have been proposed for risk assessment and outcome determination in brain arteriovenous malformations treated by endovascular therapy. We aim to validate and compare the efficacy of these scales in predicting perioperative complications and clinical outcomes.

METHODS

We retrospectively reviewed brain arteriovenous malformations patients who underwent endovascular therapy at 4 centers in China from January 2012 to December 2015. The primary outcomes were complications, unfavorable outcome (mRS ≥ 3), and complete obliteration. Each patient was assessed using the Spetzler-Martin grading system (SM), Puerto Rico scale, Buffalo score, and arteriovenous malformation embocure score (AVMES). Correlation analysis was performed between primary outcomes incidence rate and the grades of each scale. The area under the receiver operating characteristic curve of these scales was calculated. Pairwise comparison of receiver operating characteristic curves was performed to compare the efficacy of the scales.

RESULTS

A total of 270 patients were included. Correlation analysis demonstrated that the complication rate increased with increasing grade in SM (P = 0.002), Puerto Rico scale (P = 0.014), and Buffalo score (P = 0.001); complete obliteration rate decreased with increasing grade in AVMES (P = 0.017); unfavorable outcome rate increased with increasing grade in the Puerto Rico scale (P = 0.005). The area under the receiver operating characteristic curve analysis showed statistical differences between the Puerto Rico score and SM (P = 0.047) in predicting complications and between the Puerto Rico score and SM (P = 0.008) in predicting unfavorable outcomes. The area under the curve of the AVMES in predicting complete obliteration was 0.757.

CONCLUSIONS

The Puerto Rico score predicts complications and unfavorable outcomes better than the SM. The AVMES scale has medium efficacy in predicting complete obliteration.

NOTCH4 gene polymorphisms as potential risk factors for brain arteriovenous malformation development and hemorrhagic presentation

OBJECTIVE

Arteriovenous malformations (AVMs) of the brain are a frequent and important cause of intracranial hemorrhage in young adults. Little is known about the molecular-genetic pathomechanisms underlying AVM development. Genes of the NOTCH family control the normal development of vessels and proper arteriovenous specification. Transgenic mice with constitutive expression of active NOTCH4 frequently develop AVMs. Here, the authors report a genetic association study investigating possible associations between NOTCH4 gene polymorphisms and formation and clinical presentation of AVMs.

METHODS

After PCR amplification and direct DNA sequencing or restriction digests, 10 single-nucleotide polymorphisms (SNPs) of the NOTCH4 gene were used for genotyping 153 AVM patients and 192 healthy controls (i.e., blood donors). Pertinent clinical data were available for 129 patients. Uni- and multivariate single-marker and explorative haplotype analyses were performed to identify potential genetic risk factors for AVM development and for hemorrhagic or epileptic presentation.

RESULTS

Eleven calculated haplotypes consisting of 3–4 SNPs (most of which were located in the epidermal growth factor–like domain of the NOTCH4 gene) were observed significantly more often among AVM patients than among controls. Univariate analysis indicated that rs443198_TT and rs915895_AA genotypes both were significantly associated with hemorrhage and that an rs1109771_GG genotype was associated with epilepsy. The association between rs443198_TT and AVM bleeding remained significant in the multivariate regression analysis.

CONCLUSIONS

The authors' results suggest NOTCH4 SNPs as possible genetic risk factors for the development and clinical presentation of AVMs and a role of NOTCH4 in the pathogenesis of this disease.

Morbidity after Hemorrhage in Children with Untreated Brain Arteriovenous Malformation

BACKGROUND

Children with untreated brain arteriovenous malformations (bAVM) are at risk of encountering life-threatening hemorrhage very early in their lives. The primary aim of invasive treatment is to reduce unfavorable outcome associated with a bAVM rupture. A better understanding of the morbidity of bAVM hemorrhage might be helpful for weighing the risks of untreated bAVM and invasive treatment. Our aim was to assess the clinical outcome after bAVM rupture and identify features to predict severe hemorrhage in children.

METHODS

We identified all consecutive children admitted to our institution for bAVMs between July 2009 and December 2014. Clinical outcome after hemorrhagic presentation and subsequent hemorrhage was evaluated using the modified Rankin Scale (mRS) for children. The association of demographic characteristics and bAVM morphology with severe hemorrhage (mRS >3 or requiring emergency hematoma evacuation) was studied using univariate and multivariable regression analyses. A nomogram based on multivariable analysis was formulated to predict severe hemorrhage risk for individual patients.

RESULTS

A total of 134 patients were identified with a mean treatment-free follow-up period of 2.1 years. bAVM ruptured in 83 (62%) children: 82 had a hemorrhage at presentation and 6 of them experienced a recurrent hemorrhage during follow-up; 1 patient had other diagnostic symptoms but bled during follow-up. Among them, 49% (41/83) had a severe hemorrhage; emergency hematoma evacuation was required in 28% of them (23/83), and 24% (20/83) remained as disabled (mRS ≥3) at last follow-up. Forty-six percent (38/82) of children with hemorrhagic presentation were severely disabled (mRS >3). Forty-three percent (3/7) were severely disabled after subsequent hemorrhage. The annual rate of severe subsequent hemorrhage was 1% in the overall cohort and 3.3% in children with ruptured presentation. All the subsequent severe hemorrhage events occurred in children with severe hemorrhage history (7%, 3/41). Periventricular location, non-temporal lobe location, and long draining vein were predictors for severe hemorrhage in pediatric untreated bAVMs. A nomogram based on bAVM morphology was contracted to predict severe hemorrhage risk for individual patients, which was well calibrated and had a good discriminative ability (adjusted C-statistic, 0.72).

CONCLUSIONS

Evaluating bAVM morbidity and morphology might be helpful for weighing the risks of untreated bAVM in pediatric patients.

Role of follow-up imaging after resection of brain arteriovenous malformations in pediatric patients: a systematic review of the literature

OBJECTIVE Pediatric patients are at risk for the recurrence of brain arteriovenous malformation (AVM) after resection. While there is general consensus on the importance of follow-up after surgical removal of an AVM, there is a lack of consistency in the duration of that follow-up. The object of this systematic review was to examine the role of follow-up imaging in detecting AVM recurrence early and preventing AVM rupture. METHODS This systematic review was performed using articles obtained through a search of the literature contained in the MeSH database, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. RESULTS Search results revealed 1052 articles, 13 of which described 31 cases of AVM recurrence meeting the criteria for inclusion in this study. Detection of AVM occurred significantly earlier (mean ± SD, 3.56 ± 3.67 years) in patients with follow-up imaging than in those without (mean 8.86 ± 5.61 years; p = 0.0169). While 13.34% of patients who underwent follow-up imaging presented with rupture of a recurrent AVM, 57.14% of those without follow-up imaging presented with a ruptured recurrence (p = 0.0377). CONCLUSIONS Follow-up imaging has an integral role after AVM resection and is sometimes not performed for a sufficient period, leading to delayed detection of recurrence and an increased likelihood of a ruptured recurrent AVM.

Gamma Knife radiosurgery for the treatment of intracranial dural arteriovenous fistulas

Background Intracranial dural arteriovenous fistulae (DAVF) may present a treatment challenge. Endovascular embolization is in most cases the first line of treatment but does not always achieve cure. Gamma Knife (GK) radiosurgery represents an alternative treatment option, and the purpose of this study was to further evaluate its utility. Methods We reviewed all cases of DAVF treated between 2009 and 2016 at our institution with GK radiosurgery independently, or following failed/refused endovascular or surgical management. Patients' clinical files, radiological images, catheter angiograms, and surgical DAVF disconnection reports were retrospectively reviewed. Results Sixteen DAVF (14 patients) treated by GK radiosurgery were identified. Eleven fistulae were aggressive and five were benign. Marginal doses ranged from 15 to 25 Gy. Target volumes ranged from 0.04 to 4.47 cm³. In all symptomatic patients, GK treatment resulted in symptom palliation. In 13/15 lesions, cure of symptoms (86.0%) was reported. One lesion was asymptomatic. Angiographic cure was achieved in eight cases (50%), small residual DAVF occurred in four, and four were unchanged. One patient developed headache that resolved at one year. No hemorrhage occurred during the follow-up period. There was no significant association between Borden type and cure rate. Prior failed endovascular treatment and small target volume were associated with lower rates of cure. Conclusions Stereotactic radiosurgery is viable treatment for DAVF. It is very effective in palliating symptoms as a de novo approach or adjunctive to endovascular therapy. In our experience it is only somewhat effective in achieving complete angiographic cure.

Subsequent haemorrhage in children with untreated brain arteriovenous malformation: Higher risk with unbalanced inflow and outflow angioarchitecture

OBJECTIVES

Children with brain arteriovenous malformations (bAVMs) are at risk of life-threatening haemorrhage in their early lives. Our aim was to analyse various angioarchitectural features of bAVM to predict the risk of subsequent haemorrhage during follow-up in children.

METHODS

We identified all consecutive children admitted to our institution for bAVMs between July 2009 and September 2015. Children with at least 1 month of treatment-free follow-up after diagnosis were included in further analysis. Annual rates of AVM rupture as well as several potential risk factors for subsequent haemorrhage were analysed using Kaplan-Meier analyses and Cox proportional hazards regression models.

RESULTS

We identified 110 paediatric patients with a mean follow-up period of 2.1 years (range, 1 month-15.4 years). The average annual risk of haemorrhage from untreated AVMs was 4.3 % in children. No generalised venous ectasia in conjunction with fast arteriovenous shunt was predictive of subsequent haemorrhage (RR, 7.55; 95 % CI 1.96-29.06). The annual rupture risk was 11.1 % in bAVMs without generalised venous ectasia but with fast arteriovenous shunt.

CONCLUSIONS

bAVM angiographic features suggesting unbalanced inflow and outflow might be helpful to identify children at higher risk for future haemorrhage.

KEY POINTS

• Haemorrhage risk stratification is important for children with untreated brain AVM. • Angiographic features suggesting unbalanced inflow and outflow predict paediatric brain AVM haemorrhage. • Identifying AVMs with high rupture risk help patient selection and tailoring treatment.

Pediatric intracranial dural arteriovenous fistulas: age-related differences in clinical features, angioarchitecture, and treatment outcomes

OBJECTIVE Intracranial dural arteriovenous fistulas (DAVFs) are rare in children. This study sought to better characterize DAVF presentation, angioarchitecture, and treatment outcomes. METHODS Children with intracranial DAVFs between 1986 and 2013 were retrospectively identified from the neurointerventional database at the authors' institution. Demographics, clinical presentation, lesion angioarchitecture, treatment approaches, angiographic outcomes, and clinical outcomes were assessed. RESULTS DAVFs constituted 5.7% (22/423) of pediatric intracranial arteriovenous shunting lesions. Twelve boys and 10 girls presented between 1 day and 18 years of age; boys presented at a median of 1.3 years and girls presented at a median of 4.9 years. Four of 8 patients ≤ 1 year of age presented with congestive heart failure compared with 0/14 patients > 1 year of age (p = 0.01). Five of 8 patients ≤ 1 year old presented with respiratory distress compared with 0/14 patients > 1 year old (p = 0.0021). Ten of 14 patients > 1 year old presented with focal neurological deficits compared with 0/8 patients ≤ 1 year old (p = 0.0017). At initial angiography, 16 patients harbored a single intracranial DAVF and 6 patients had 2-6 DAVFs. Eight patients (38%) experienced DAVF obliteration by the end of treatment. Good clinical outcome (modified Rankin Scale score 0-2) was documented in 77% of patients > 1 year old at presentation compared with 57% of patients ≤ 1 year old at presentation. Six patients (27%) died. CONCLUSIONS Young children with DAVFs presented predominantly with cardiopulmonary symptoms, while older children presented with focal neurological deficits. Compared with other pediatric vascular shunts, DAVFs had lower rates of angiographic obliteration and poorer clinical outcomes.

Genome-wide association study of sporadic brain arteriovenous malformations

BACKGROUND

The pathogenesis of sporadic brain arteriovenous malformations (BAVMs) remains unknown, but studies suggest a genetic component. We estimated the heritability of sporadic BAVM and performed a genome-wide association study (GWAS) to investigate association of common single nucleotide polymorphisms (SNPs) with risk of sporadic BAVM in the international, multicentre Genetics of Arteriovenous Malformation (GEN-AVM) consortium.

METHODS

The Caucasian discovery cohort included 515 BAVM cases and 1191 controls genotyped using Affymetrix genome-wide SNP arrays. Genotype data were imputed to 1000 Genomes Project data, and well-imputed SNPs (>0.01 minor allele frequency) were analysed for association with BAVM. 57 top BAVM-associated SNPs (51 SNPs with p<10(-05) or p<10(-04) in candidate pathway genes, and 6 candidate BAVM SNPs) were tested in a replication cohort including 608 BAVM cases and 744 controls.

RESULTS

The estimated heritability of BAVM was 17.6% (SE 8.9%, age and sex-adjusted p=0.015). None of the SNPs were significantly associated with BAVM in the replication cohort after correction for multiple testing. 6 SNPs had a nominal p<0.1 in the replication cohort and map to introns in EGFEM1P, SP4 and CDKAL1 or near JAG1 and BNC2. Of the 6 candidate SNPs, 2 in ACVRL1 and MMP3 had a nominal p<0.05 in the replication cohort.

CONCLUSIONS

We performed the first GWAS of sporadic BAVM in the largest BAVM cohort assembled to date. No GWAS SNPs were replicated, suggesting that common SNPs do not contribute strongly to BAVM susceptibility. However, heritability estimates suggest a modest but significant genetic contribution.

Sex-dichotomous effects of NOS1AP promoter DNA methylation on intracranial aneurysm and brain arteriovenous malformation

The goal of this study was to investigate the contribution of NOS1AP-promoter DNA methylation to the risk of intracranial aneurysm (IA) and brain arteriovenous malformation (BAVM) in a Han Chinese population. A total of 48 patients with IAs, 22 patients with BAVMs, and 26 control individuals were enrolled in the study. DNA methylation was tested using bisulfite pyrosequencing technology. We detected significantly higher DNA methylation levels in BAVM patients than in IA patients based on the multiple testing correction (CpG4-5 methylation: 5.86±1.04% vs. 4.37±2.64%, P=0.006). In women, CpG4-5 methylation levels were much lower in IA patients (3.64±1.97%) than in BAVM patients (6.11±1.20%, P<0.0001). However, in men, CpG1-3 methylation levels were much higher in the controls (6.92±0.78%) than in BAVM patients (5.99±0.70%, P=0.008). Additionally, there was a gender-based difference in CpG1 methylation within the controls (men vs. women: 5.75±0.50% vs. 4.99±0.53%, P=0.003) and BAVM patients (men vs. women: 4.70±0.74% vs. 5.50±0.87%, P=0.026). A subgroup analysis revealed significantly higher CpG3 methylation in patients who smoked than in those who did not (P=0.041). Our results suggested that gender modulated the interaction between NOS1AP promoter DNA methylation in IA and BAVM patients. Our results also confirmed that regular tobacco smoking was associated with increased NOS1AP methylation in humans. Additional studies with larger sample sizes are required to replicate and extend these findings.

Progressive versus Nonprogressive Intracranial Dural Arteriovenous Fistulas: Characteristics and Outcomes

BACKGROUND AND PURPOSE

A minority of intracranial dural arteriovenous fistulas progress with time. We sought to determine features that predict progression and define outcomes of patients with progressive dural arteriovenous fistulas.

MATERIALS AND METHODS

We performed a retrospective imaging and clinical record review of patients with intracranial dural arteriovenous fistula evaluated at our hospital.

RESULTS

Of 579 patients with intracranial dural arteriovenous fistulas, 545 had 1 fistula (mean age, 45 ± 23 years) and 34 (5.9%) had enlarging, de novo, multiple, or recurrent fistulas (mean age, 53 ± 20 years; P = .11). Among these 34 patients, 19 had progressive dural arteriovenous fistulas with de novo fistulas or fistula enlargement with time (mean age, 36 ± 25 years; progressive group) and 15 had multiple or recurrent but nonprogressive fistulas (mean age, 57 ± 13 years; P = .0059, nonprogressive group). Whereas all 6 children had fistula progression, only 13/28 adults (P = .020) progressed. Angioarchitectural correlates to chronically elevated intracranial venous pressures, including venous sinus dilation (41% versus 7%, P = .045) and pseudophlebitic cortical venous pattern (P = .048), were more common in patients with progressive disease than in those without progression. Patients with progressive disease received more treatments than those without progression (median, 5 versus 3; P = .0068), but as a group, they did not demonstrate worse clinical outcomes (median mRS, 1 and 1; P = .39). However, 3 young patients died from intracranial venous hypertension and intracranial hemorrhage related to progression of their fistulas despite extensive endovascular, surgical, and radiosurgical treatments.

CONCLUSIONS

Few patients with dural arteriovenous fistulas follow an aggressive, progressive clinical course despite treatment. Younger age at initial presentation and angioarchitectural correlates to venous hypertension may help identify these patients prospectively.

Validation of the supplemented Spetzler-Martin grading system for brain arteriovenous malformations in a multicenter cohort of 1009 surgical patients

BACKGROUND

The supplementary grading system for brain arteriovenous malformations (AVMs) was introduced in 2010 as a tool for improving preoperative risk prediction and selecting surgical patients.

OBJECTIVE

To demonstrate in this multicenter validation study that supplemented Spetzler-Martin (SM-Supp) grades have greater predictive accuracy than Spetzler-Martin (SM) grades alone.

METHODS

Data collected from 1009 AVM patients who underwent AVM resection were used to compare the predictive powers of SM and SM-Supp grades. Patients included the original 300 University of California, San Francisco patients plus those treated thereafter (n = 117) and an additional 592 patients from 3 other centers.

RESULTS

In the combined cohort, the SM-Supp system performed better than SM system alone: area under the receiver-operating characteristics curve (AUROC) = 0.75 (95% confidence interval, 0.71-0.78) for SM-Supp and AUROC = 0.69 (95% confidence interval, 0.65-0.73) for SM (P < .001). Stratified analysis fitting models within 3 different follow-up groupings (<6 months, 6 months-2 years, and >2 years) demonstrated that the SM-Supp system performed better than SM system for both medium (AUROC = 0.71 vs 0.62; P = .003) and long (AUROC = 0.69 vs 0.58; P = .001) follow-up. Patients with SM-Supp grades ≤6 had acceptably low surgical risks (0%-24%), with a significant increase in risk for grades >6 (39%-63%).

CONCLUSION

This study validates the predictive accuracy of the SM-Supp system in a multicenter cohort. An SM-Supp grade of 6 is a cutoff or boundary for AVM operability. Supplemented grading is currently the best method of estimating neurological outcomes after AVM surgery, and we recommend it as a starting point in the evaluation of AVM operability.

Periventricular Location as a Risk Factor for Hemorrhage and Severe Clinical Presentation in Pediatric Patients with Untreated Brain Arteriovenous Malformations

BACKGROUND AND PURPOSE

The morphologic features of brain arteriovenous malformations differ between children and adults; therefore, our aim was to analyze various features of brain arteriovenous malformations to assess the risk of hemorrhage in children.

MATERIALS AND METHODS

We identified all consecutive children admitted to Beijing Tiantan Hospital for brain arteriovenous malformations between July 2009 and April 2014. The effects of demographic characteristics and brain arteriovenous malformation morphology on hemorrhage presentation, annual bleeding rates, postnatal hemorrhage, and immediate posthemorrhagic neurologic outcomes were studied by using univariate and multivariable regression analyses.

RESULTS

A total of 108 pediatric brain arteriovenous malformation cases were identified, 66 (61.1%) of which presented with hemorrhage. Of these, 69.7% of ruptured brain arteriovenous malformations were in a periventricular location. Periventricular nidus location (OR, 3.443; 95% CI, 1.328-8.926; P = .011) and nidus size (OR, 0.965; 95% CI, 0.941-0.989; P = .005) were independent predictors of hemorrhagic presentation. The annual hemorrhage rates in children with periventricular brain arteriovenous malformations were higher at 6.88% (OR, 1.965; 95% CI, 1.155-3.341; P < .05). The hemorrhage-free survival rates were also lower for children with periventricular brain arteriovenous malformations (log-rank, P = .01). Periventricular location (hazard ratio, 1.917; 95% CI, 1.131-3.250; P = .016) and nidus size (hazard ratio, 0.983; 95% CI, 0.969-0.997; P = .015) were associated with hemorrhage after birth in pediatric brain arteriovenous malformations. An ordinal analysis showed lower immediate posthemorrhage mRS in patients with periventricular brain arteriovenous malformations (OR for greater disability, 2.71; 95% CI, 1.03-7.11; P = .043).

CONCLUSIONS

Small periventricular brain arteriovenous malformations were associated with increased hemorrhage risk in pediatric patients. Cautious follow-up of children with untreated periventricular brain arteriovenous malformations is recommended because of a higher hemorrhage risk and potentially more severe neurologic outcomes.

Natural history of brain arteriovenous malformations: a systematic review

OBJECT

The authors aimed to systematically review the literature to clarify the natural history of brain arteriovenous malformations (BAVMs).

METHODS

The authors searched PubMed for one or more of the following terms: natural history, brain arteriovenous malformations, cerebral arteriovenous malformations, and risk of rupture. They included studies that reported annual rates of hemorrhage and that included either 100 patients or 5 years of treatment-free follow-up.

RESULTS

The incidence of BAVMs is 1.12-1.42 cases per 100,000 person-years; 38%-68% of new cases are first-ever hemorrhage. The overall annual rates of hemorrhage for patients with untreated BAVMs range from 2.10% to 4.12%. Consistently implicated in subsequent hemorrhage are initial hemorrhagic presentation, exclusively deep venous drainage, and deep and infrantentorial brain location. The risk for rupture seems to be increased by large nidus size and concurrent arterial aneurysms, although these factors have not been studied as thoroughly. Venous stenosis has not been implicated in increased risk for rupture.

CONCLUSIONS

For patients with BAVMs, although the overall risk for hemorrhage seems to be 2.10%-4.12% per year, calculating an accurate risk profile for decision making involves clinical attention and accounting for specific features of the malformation.

Association between Venous Angioarchitectural Features of Sporadic Brain Arteriovenous Malformations and Intracranial Hemorrhage

BACKGROUND AND PURPOSE

Intracranial hemorrhage is the most serious outcome for brain arteriovenous malformations. This study examines associations between venous characteristics of these lesions and intracranial hemorrhage.

MATERIALS AND METHODS

Statistical analysis was performed on a prospectively maintained data base of brain AVMs evaluated at an academic medical center. DSA, CT, and MR imaging studies were evaluated to classify lesion side, drainage pattern, venous stenosis, number of draining veins, venous ectasia, and venous reflux. Logistic regression analyses were performed to identify the association of these angiographic features with intracranial hemorrhage of any age at initial presentation.

RESULTS

Exclusively deep drainage (OR, 3.42; 95% CI, 1.87-6.26; P < .001) and a single draining vein (OR, 1.98; 95% CI, 1.26-3.08; P = .002) were associated with hemorrhage, whereas venous ectasia (OR, 0.52; 95% CI, 0.34-0.78; P = .002) was inversely associated with hemorrhage.

CONCLUSIONS

Analysis of venous characteristics of brain AVMs may help determine their prognosis and thereby identify lesions most appropriate for treatment.

A quantitative analysis of adverse radiation effects following Gamma Knife radiosurgery for arteriovenous malformations

OBJECT

The authors review outcomes following Gamma Knife radiosurgery (GKRS) of cerebral arteriovenous malformations (AVMs) and their correlation to postradiosurgery adverse radiation effects (AREs).

METHODS

From a prospective institutional review board-approved database, the authors identified patients with a minimum of 2 years of follow-up and thin-slice T2-weighted MRI sequences for volumetric analysis. A total of 105 AVM patients were included. The authors analyzed the incidence and quantitative changes in AREs as a function of time after GKRS. Statistical analysis was performed to identify factors related to ARE development and changes in the ARE index.

RESULTS

The median clinical follow-up was 53.8 months (range 24-212.4 months), and the median MRI follow-up was 36.8 months (range 24-212.4 months). 47.6% of patients had an AVM with a Spetzler-Martin grade ≥ III. The median administered margin and maximum doses were 22 and 40 Gy, respectively. The overall obliteration rate was 70.5%. Of patients who showed complete obliteration, 74.4% developed AREs within 4-6 months after GKRS. Late-onset AREs (i.e., > 12 months) correlated to a failure to obliterate the nidus. 58.1% of patients who developed appreciable AREs (defined as ARE index > 8) proceeded to have a complete nidus obliteration. Appreciable AREs were found to be influenced by AVM nidus volume > 3 ml, lobar location, number of draining veins and feeding arteries, prior embolization, and higher margin dose. On the other hand, a minimum ARE index > 8 predicted obliteration (p = 0.043).

CONCLUSIONS

ARE development after radiosurgery follows a temporal pattern peaking at 7-12 months after stereotactic radiosurgery. The ARE index serves as an important adjunct tool in patient follow-up and outcome prediction.

Hemorrhage rates from brain arteriovenous malformation in patients with hereditary hemorrhagic telangiectasia

BACKGROUND AND PURPOSE

Hereditary hemorrhagic telangiectasia (HHT) is a systemic disease characterized by mucocutaneous telangiectasias, epistaxis, and arteriovenous malformations (AVMs). Intracranial hemorrhage (ICH) rates in this population are not well described. We report ICH rates and characteristics in HHT patients with brain AVMs (HHT-BAVMs).

METHODS

We studied the first 153 HHT-BAVM patients with follow-up data enrolled in the Brain Vascular Malformation Consortium HHT Project. We estimated ICH rates after BAVM diagnosis.

RESULTS

The majority of patients were women (58%) and white (98%). The mean age at BAVM diagnosis was 31±19 years (range, 0-70), with 61% of cases diagnosed on asymptomatic screening. Overall, 14% presented with ICH; among symptomatic cases, 37% presented ruptured. During 493 patient-years of follow-up, 5 ICH events occurred yielding a rate of 1.02% per year (95% confidence interval, 0.42-2.44%). ICH-free survival differed significantly by ICH presentation (P=0.003); ruptured cases had a higher ICH rate (10.07%; 95% confidence interval, 3.25-31.21%) than unruptured cases (0.43%; 95% confidence interval, 0.11-1.73%).

CONCLUSIONS

Patients with HHT-BAVM who present with hemorrhage are at a higher risk for rehemorrhage compared with patients with BAVM detected presymptomatically.

Associated Aneurysms in Supratentorial Arteriovenous Malformations: Impact of Aneurysm Size on Haemorrhage

Background: Associated aneurysms (AAs) are presumed to represent an additional risk factor for intracranial haemorrhage from cerebral arterio-venous malformations (AVMs). To date, efforts to capture their natural history, as well as to identify aneurysms with the potential capability of regression after AVM treatment remain incomprehensive. As the aneurysm size represents an important aspect for the treatment indication of incidental saccular aneurysms, this factor has rarely been encountered for the treatment of AAs so far. The present study aims to determine the angiographic and clinical characteristics of AAs with special focus on aneurysm size and their consequences for treatment. Methods: Patients with cerebral AVMs, treated in our department between 1990 and 2013, were analyzed retrospectively. Only patients with supratentorial AVMs and flow-related AAs of the feeding arteries were evaluated. Thus, patients harboring AVMs of the cerebellum and the brain stem and patients with intranidal, venous or remote aneurysms were excluded. Treatment strategies were assessed with special attention on bleeding source and on AA size. Results: In 59 of 409 patients (14%) with supratentorial AVMs, a total of 85 AAs of the feeding arteries were identified. 14 of 59 individuals (24%) presented with multiple AAs. Of 85 AA, 58 aneurysms (68%) were classified as proximal and 27 aneurysms (32%) as distal. The most common location of AAs was the middle cerebral artery (MCA, 39%), followed by the internal carotid artery (ICA, 27%) and the anterior cerebral artery (ACA, 21%). The mean AA size was 4.4 mm ± 3.4 mm. Intracranial haemorrhage was found in 21 of 59 patients (36%) with coexisting AAs. Among these, 10 individuals (17%) suffered from rupture of an AA, accounting for nearly half of all bleedings in this subgroup. Among those patients bearing a single AA, the size of ruptured aneurysms differed significantly from those unruptured (6.6 mm vs. 4.4 mm, p = 0.0046). Nineteen patients (32%) received treatment of 22 AAs, whereas sole AVM treatment was adopted in 26 patients (44%) and conservative management in 14 patients (24%). The main reasons to leave AAs untreated were the small AA size (<5 mm), poor clinical state or treatment denial by the patients. Conclusions: The aneurysm size of AAs in AVM influences the risk of haemorrhage. Therefore, the treatment of larger (diameter ≥5 mm) AAs should be considered, even if a treatment indication of the associated AVM is not given.

Radiosurgical Retreatment for Brain Arteriovenous Malformation

Objective:

To analyze our experience with a second radiosurgical treatment for brain arteriovenous malformations (BAVMs) after an unsuccessful first radiosurgical treatment.

Methods:

Between 1993 and 2000, 242 patients were treated by the Toronto Sunnybrook Regional Cancer Center using a LINAC system. Fifteen of these patients required a second radiosurgical intervention due to the failure of the first procedure. Data was collected on baseline patient characteristics, BAVM features, radiosurgery treatment plan and outcomes. Brain arteriovenous malformation obliteration was determined by follow-up MRI and angiography and the obliteration prediction index (OPI) calculated according to a previously established formula.

Results:

The median interval between the first and second treatment was 46 months (range 39-109). The median follow-up after the second procedure was 39 months (range 26 to 72). The mean BAVM volume before the first treatment was 8.9cm3 (range 0.3-21) and before the second treatment was 3.6cm3 (range 0.2-11.6). The mean marginal dose during the first treatment was 18Gy (range 12-25) and during the second treatment was 16Gy (range 12-20). After the second treatment, nine patients had obliteration of their BAVM confirmed by angiography and one patient had obliteration confirmed by MRI, resulting in an obliteration rate of 66.6%, which is very comparable to that predicted by the OPI (65%). After the second treatment two patients had a radiation-induced complication (13.3%).

Conclusion:

Retreatment of BAVM using a second radiosurgery procedure is a safe and effective option that offers the same rate of success as the initial radiosurgery and an acceptable risk of radiation-induced complication.