Long-term excess mortality in 623 patients with brain arteriovenous malformations

Haemorrhagic stroke and brain vascular malformations in women: risk factors and clinical features

Haemorrhagic stroke is a severe condition with poor prognosis. Biological sex influences the risk factors, presentations, treatment, and patient outcomes of intracerebral haemorrhage, aneurysmal subarachnoid haemorrhage, and vascular malformations. Women are usually older at onset of intracerebral haemorrhage compared with men but have an increased risk of aneurysmal subarachnoid haemorrhage as they age. Female-specific factors such as pregnancy, eclampsia or pre-eclampsia, postmenopausal status, and hormone therapy influence a woman's long-term risk of haemorrhagic stroke. The presence of intracranial aneurysms, arteriovenous malformations, or cavernous malformations poses unique clinical dilemmas during pregnancy and delivery. In the absence of evidence-based guidelines for managing the low yet uncertain risk of haemorrhagic stroke during pregnancy and delivery in women with vascular malformations, multidisciplinary teams should carefully assess the risks and benefits of delivery methods for these patients. Health-care providers should recognise and address the challenges that women might have to confront when recovering from haemorrhagic stroke.

Prediction of Obliteration After the Gamma Knife Radiosurgery of Arteriovenous Malformations Using Hand-Crafted Radiomics and Deep-Learning Methods

INTRODUCTION

Brain arteriovenous malformations (bAVMs) are vascular abnormalities that can be treated with embolization or radiotherapy to prevent the risk of future rupture. In this study, we use hand-crafted radiomics and deep learning techniques to predict favorable vs. unfavorable outcomes following Gamma Knife radiosurgery (GKRS) of bAVMs and compare their prediction performances.

METHODS

One hundred twenty-six patients seen at one academic medical center for GKRS obliteration of bAVMs over 15 years were retrospectively reviewed. Forty-two patients met the inclusion criteria. Favorable outcomes were defined as complete nidus obliteration demonstrated on cerebral angiogram and asymptomatic recovery. Unfavorable outcomes were defined as incomplete obliteration or complications relating to the AVM that developed after GKRS. Outcome predictions were made using a random forest model with hand-crafted radiomic features and a fine-tuned ResNet-34 convolutional neural network (CNN) model. The performance was evaluated by using a ten-fold cross-validation technique.

RESULTS

The average accuracy and area-under-curve (AUC) values of the Random Forest Classifier (RFC) with radiomics features were 68.5 ±9.80% and 0.705 ±0.086, whereas those of the ResNet-34 model were 60.0 ±11.9% and 0.694 ±0.124. Four radiomics features used with RFC discriminated unfavorable response cases from favorable response cases with statistical significance. When cropped images were used with ResNet-34, the accuracy and AUC decreased to 59.3 ± 14.2% and 55.4 ±10.4%, respectively.

CONCLUSIONS

A hand-crafted radiomics model and a pre-trained CNN model can be fine-tuned on pre-treatment MRI scans to predict clinical outcomes of AVM patients undergoing GKRS with equivalent prediction performance. The outcome predictions are promising but require further external validation on more patients.

Vascular stability of brain arteriovenous malformations after partial embolization

INTRODUCTION

Brain arteriovenous malformation (bAVM) might have a higher risk of rupture after partial embolization, and previous studies have shown that some metrics of vascular stability are related to bAVM rupture risk.

OBJECTIVE

To analyze vascular stability of bAVM in patients after partial embolization.

METHODS

Twenty-four patients who underwent partial embolization were classified into the short-term, medium-term, and long-term groups, according to the time interval between partial embolization and surgery. The control group consisted of 9 bAVM patients who underwent surgery alone. Hemodynamic changes after partial embolization were measured by angiogram. The inflammatory infiltrates and cell-cell junctions were evaluated by MMP-9 and VE-cadherin. At the protein level, the proliferative and apoptotic events of bAVMs were analyzed by immunohistochemical staining of VEGFA, eNOS, and caspase-3. Finally, neovascularity and apoptotic cells were assessed by CD31 staining and TUNEL staining.

RESULTS

Immediately after partial embolization, the blood flow velocity of most bAVMs increased. The quantity of MMP-9 in the medium-term group was the highest, and VE-cadherin in the medium-term group was the lowest. The expression levels of VEGFA, eNOS, and neovascularity were highest in the medium-term group. Similarly, the expression level of caspase-3 and the number of apoptotic cells were highest in the medium-term group.

CONCLUSION

The biomarkers for bAVM vascular stability were most abnormal between 1 and 28 days after partial embolization.

Microsurgical Treatment of Arteriovenous Malformations: A Single-Center Study Experience

OBJECTIVE

The purpose of the study was to assess the functional outcomes after microsurgical resection of arteriovenous malformations (AVMs) and to compare the results between patients eligible for A Randomized Trial of Unruptured Brain Arteriovenous Malformations in this surgical series to the results reported and the ARUBA study.

METHODS

We reviewed the records of 169 patients who underwent microsurgical treatment of arteriovenous malformation (AVMs) in our institution between January 2016 and December 2021. These patients' functional status was assessed using modified Rankin Scale (mRS) scores at the last follow-up and before treatment. The mRS scores at the latest follow-up were classified into good outcomes (mRS < 3) and poor outcomes (mRS ≥ 3). Clinical presentation, patients' demographics, AVM characteristics, follow-up time, and obliteration rate were analyzed. Subgroup analyses were performed on the whole cohort, comparing Spetzler-Martin Grade I and Grade II, and ARUBA-eligible AVMs.

RESULTS

The initial hemorrhagic presentation occurred in 71 (42%) out of 169 patients. The majority of the patients presented with headaches (73%). The AVMs were completely obliterated in 166 (98.2%) patients. The series included 65 Spetzler-Martin Grade I (38.5%), 46 Grade II (27.2%), 32 Grade III (18.9%), 22 Grade IV (13%), and 4 Grade V (2.4%) AVMs. There were 98 unruptured and 79 ARUBA-eligible cases. Also, optimal functional outcome was achieved in 145 (85.8%) patients. The overall mortality rate was 5.3% (9/169). The multivariate analysis illustrated that a poor outcome was significantly associated with presurgical mRS ≥3 (p < 0.013; OR, 0.206; 95% CI 0.059-0.713), increasing age (p < 0.045; odds ratio [OR], 1.022; 95% CI 1.000-0.045), and female gender (p < 0.009; OR, 2.991; 95% CI 1.309-6.832).

CONCLUSIONS

Our study suggests that better outcomes can be obtained using microsurgical resection in the majority of patients with AVMs. Independent predictors of poor outcomes after surgical resection of AVMs include increasing age at the time of surgery, poor presurgical functional status, and female gender. Supposing that patients are more suitable for microsurgery after presurgical examination, outcomes are normally better in that case than those achieved by multimodal interventions (such as conservative treatment or ARUBA treatment arm). Therefore, we recommend early surgical removal on all surgically accessible AVMs to prevent successive hemorrhages and the consequences of poor neurological outcomes.

Management of Brain Arteriovenous Malformations: A Review

Brain arteriovenous malformations (bAVM) are vascular malformations of the brain affecting all ages. The optimum management strategy is essentially devoid of high-quality evidence and is highly nuanced and embedded in local customs. This study summarizes the frequently employed management strategies, drawing conclusions on the utility of each method of treatment and delving into controversies surrounding them. A literature search on PubMed and Medline was done on January 3^rd, 2022. 11,767 articles were found, and abstracts were reviewed. Full-text review of 153 articles led to chapters from three books and 71 articles incorporated into a summative discussion. Spetzler-Ponce (S-P) Class A patients may be offered surgery if they are good surgical candidates and have a good number of high-quality years of life left. The exception is diffuse Spetzler-Martin (S-M) grade 2 in a patient older than 40 years: radiosurgery for unruptured and embolization for ruptured. S-P Class B may be offered surgery if a compact nidus or if younger than 40 years. If diffuse or age greater than 40, radiosurgery may be preferred if the Pollock-Flickinger score is less than 2.5. For the remainder of S-P Class B, conservative management may be preferred. S-P Class C is generally not treated unless young or those patients with poorly controlled seizures affecting their quality of life are willing to risk permanent neurological deficits. While the quality of studies is generally high, the level of evidence is concerning with only one randomized controlled trial (RCT). Most research output hails from high-income countries, i.e., perhaps not universally applicable to all settings owing to possible genetic, environmental, and resource differences. More research is needed: large volume studies in the pregnant population, validation of scoring systems in pediatric age groups, clinical trials focused on combination multi-staged treatment modalities, and studies originating from the developing world.

State of the Art in the Role of Endovascular Embolization in the Management of Brain Arteriovenous Malformations-A Systematic Review

As a significant cause of intracerebral hemorrhages, seizures, and neurological decline, brain arteriovenous malformations (bAVMs) are a rare group of complex vascular lesions with devastating implications for patients' quality of life. Although the concerted effort of the scientific community has improved our understanding of bAVM biology, the exact mechanism continues to be elucidated. Furthermore, to this day, due to the high heterogeneity of bAVMs as well as the lack of objective data brought by the lack of evaluative and comparative studies, there is no clear consensus on the treatment of this life-threatening and dynamic disease. As a consequence, patients often fall short of obtaining the optimal treatment. Endovascular embolization is an inherent part of multidisciplinary bAVM management that can be used in various clinical scenarios, each with different objectives. Well-trained neuro-interventional centers are proficient at curing bAVMs that are smaller than 3 cm; are located superficially in noneloquent areas; and have fewer, larger, and less tortuous feeding arteries. The transvenous approach is an emerging effective and safe technique that potentially offers a chance to cure previously untreatable bAVMs. This review provides the state of the art in all aspects of endovascular embolization in the management of bAVMs.

Natural history and treatment of deep-seated brain arteriovenous malformations in pediatric patients

OBJECTIVE

Pediatric deep brain arteriovenous malformations (bAVMs) represent a unique management challenge given their higher cumulative risk of hemorrhage as well as a higher risk of treatment. Better understanding of hemorrhage risk in this patient population will lead to a better decision-making process for patient management.

METHODS

The authors retrospectively reviewed their institutional bAVM database from 1990 to 2019 and included patients younger than 21 years who had deep-seated bAVMs. They present the annual hemorrhage risk, during the natural history and after treatment, and functional outcomes.

RESULTS

Thirty-one pediatric patients were included in this study (13 males and 18 females) with a mean age of 11.8 (SD 4.4) years. The most frequent presenting symptoms were headache (54.8%), weakness (38.7%), and seizure (22.6%). The mean follow-up duration was 13.14 (SD 12.5) years, during which 7 (22.6%) AVMs were obliterated, 10 (32.3%) individuals experienced hemorrhage, and the modified Rankin Scale score worsened in 8 (25.8%) patients. The annual natural history risk of hemorrhage was 3.24% per patient, and the overall annual hemorrhage risk after treatment was 1.98% per patient. In particular, the risk was reduced to 0.64% per patient in the stereotactic radiosurgery (SRS) group. Non-White race showed a trend of higher rupture at presentation (OR 5 [95% CI 0.84-41.68], p = 0.09). Female sex was associated with higher odds (OR 13.076 [95% CI 1.424-333.591], p = 0.048) and SRS was associated with lower odds (OR 0.122 [95% CI 0.011-0.862], p = 0.049) of follow-up hemorrhage.

CONCLUSIONS

Given the substantial cumulative risk of lifelong hemorrhagic stroke in pediatric patients, timely definitive treatment is warranted. SRS may be beneficial when the risk-benefit profile is deemed acceptable.

Critical Appraisal of Randomized Controlled Trials on Unruptured Brain Arteriovenous Malformations

OBJECTIVE

Brain arteriovenous malformations management remains controversial despite the numerous, available treatment options. Randomized controlled trials (RCTs) theoretically provide the strongest evidence for the assessment of any therapeutic intervention. However, poorly designed RCTs may be associated with biases, inaccuracies, and misleading conclusions. The purpose of our study is to assess reporting transparency and methodological quality of the existing RCTs.

METHODS

A search was performed in the PubMed, Scopus, Embase, clinicaltrials.gov, and Cochrane databases. The search was limited to English literature. We included all published RCTs reporting on the management of unruptured brain arteriovenous malformations. The eligible studies were evaluated by 5 blinded raters with the CONsolidated Standards of Reporting Trials 2010 statement and the risk-of-bias 2 tool. The inter-rater agreement was assessed with the Fleiss' Kappa.

RESULTS

A randomized trial of unruptured brain arteriovenous malformations (ARUBA) and treatment of brain arteriovenous malformations (TOBAS) trials were evaluated. ARUBA achieved high CONsolidated standards of reporting trials compliance, while TOBAS showed a moderate one. In ARUBA the introduction, discussion, and other information sections reached the highest compliance rate (80%-86%). The lowest rates were recorded in the results and the methods (62% and 73%, respectively). The inter-rater agreement was moderate to substantial (54.1% to 78.4%). All the examined studies demonstrated a high risk of bias, mainly related to ill-defined intended interventions, missing outcome data, and selection of the reported results.

CONCLUSIONS

Our study confirmed the high risk of bias mainly attributed to several protocol violations, deviations, minimal external validity and selection, attrition, and allocation biases of the ARUBA trial. Analysis of the TOBAS trial revealed a moderate overall reporting clarity and a high risk of bias.

Linac-based stereotactic radiosurgery for brain arteriovenous malformations

PURPOSE

Linac stereotactic radiosurgery (SRS) is gaining popularity as a form of radiation treatment for cerebral arteriovenous malformations (AVMs) since the theory of combined radiosurgical and endovascular treatment poses much uncertainty and due to significant technical progress for SRS. This study focuses on how to evaluate obliteration and re-bleeding rates, and to determine factors and adverse effects influencing obliteration after linac-based SRS for cerebral AVMs.

MATERIAL AND METHODS

From a statistical record of 71 patients, 31 had partial embolisation, five surgery and 29 had no prior treatment. Using Kaplan-Meier survival and life table analyses, actuarial obliteration and annual bleeding hazard rates were calculated after SRS.

RESULTS

After a follow up of 1, 2 and 3 years the actual obliteration rates were 22, 59 and 66%, respectively whereby it was noted that prior embolization had no effect on the obliteration rate. Annual bleeding hazard rates were further analyzed after stereotactic radiosurgery to be 2.1% and 1.4% for the first and second year respectively. Asymptomatic abnormalities were detected after imaging in 33.9% of patients. A dose of less than 18 Gy significantly reduced the obliteration probability.

CONCLUSION

SRS is a therapeutic option for intracerebral AVM. In general, there is a low rate of morbidity and a high probability of nidus obliteration.

Is there an Influence of Match and Mismatch of Venous Drainage Pattern on AVM Hemorrhagic Presentation?

Objective

To analyze whether there is an influence of match and mismatch of venous drainage patterns on arteriovenous malformation (AVM) hemorrhagic presentation.

Methods

Consecutive 161 patients of AVM between 2014 and 2017 were retrospectively reviewed. Venous drainage was considered deep or superficial. Match of venous drainage pattern was defined as a superficial AVM with only superficial venous drainage or a deep AVM with deep venous drainage. Mismatch of venous drainage pattern was defined as a superficial AVM involving a deep venous drainage. Univariate analysis was used to assess the influence of match and mismatch of venous drainage pattern on AVM hemorrhagic presentation.

Results

AVM location and venous drainage were matched in 116 patients, including superficial location with superficial venous drainage or deep location with deep venous drainage, and were mismatched in 45 patients, including superficial location with deep venous drainage. The rupture proportion of mismatch venous drainage pattern was statistically comparable to that of deep location with deep drainage (P = 0.819). However, superficial location with deep venous drainage was statistically associated with a higher rupture percentage than that of superficial location with superficial venous drainage (P = 0.003).

Conclusions

Mismatch venous drainage pattern or an exclusively deep venous drainage is associated with an initial clinical presentation with an AVM hemorrhage.

Stereotactic radiosurgery for ruptured versus unruptured intracranial arteriovenous malformations

Background:

There are a limited data examining the effects of prior hemorrhage on outcomes after stereotactic radiosurgery (SRS). The goal of this study was to identify risk factors for arteriovenous malformation (AVM) rupture and compare outcomes, including post-SRS hemorrhage, between patients presenting with ruptured and unruptured AVMs.

Methods:

A retrospective review of consecutive patients undergoing SRS for intracranial AVMs between 2009 and 2019 at our institution was conducted. Chi-square and multivariable logistic regression analyses were utilized to identify patient and AVM factors associated with AVM rupture at presentation and outcomes after SRS including the development of recurrent hemorrhage in both ruptured and unruptured groups.

Results:

Of 210 consecutive patients with intracranial AVMs treated with SRS, 73 patients (34.8%) presented with AVM rupture. Factors associated with AVM rupture included smaller AVM diameter, deep venous drainage, cerebellar location, and the presence of intranidal aneurysms (P < 0.05). In 188 patients with adequate follow-up time (mean 42.7 months), the overall post-SRS hemorrhage rate was 8.5% and was not significantly different between ruptured and unruptured groups (10.3 vs. 7.5%, P = 0.51). There were no significant differences in obliteration rate, time to obliteration, or adverse effects requiring surgery or steroids between unruptured and ruptured groups.

Conclusion:

Smaller AVM size, deep venous drainage, and associated intranidal aneurysms were associated with rupture at presentation. AVM rupture at presentation was not associated with an increased risk of recurrent hemorrhage or other complication after SRS when compared to unruptured AVM presentation. Obliteration rates were similar between ruptured and unruptured groups.

Vascular Lesions of the Pineal Region: A Comprehensive Review of the Therapeutic Options

OBJECTIVE

Vascular lesions of the pineal region comprise aneurysms of the pineal region, arteriovenous malformations, cavernous malformations, and vein of Galen malformations. In the present report, we have offered an extensive review of each vascular pineal region lesion.

METHODS

We performed an extensive literature review, focusing on the current therapeutic options available for the different vascular lesions of the pineal region.

RESULTS

Vascular lesions of the pineal region are rare. Microneurosurgery remains a valid treatment of cavernomas, arteriovenous malformations, and aneurysms. Endovascular treatments seem to be the first option for the vein of Galen malformations, followed by microneurosurgery. Radiosurgery seems beneficial for small-size arteriovenous malformations. Complex and large vascular lesions will require a combination of multiple treatments.

CONCLUSIONS

Vascular lesions of the pineal region are complex, uncommon diseases. Thus, definitive therapeutic modalities for these lesions require further research.

State of the Art and Future Direction in Diagnosis, Molecular Biology, Genetics, and Treatment of Brain Arteriovenous Malformations

Brain arteriovenous malformations (bAVMs) are uncommon and represent a heterogeneous group of lesions. Although these 2 facts have delayed research on this topic, knowledge about the pathophysiology, diagnosis, and treatment of bAVMs has evolved in recent years. We conducted a review of the literature to update the knowledge about diagnosis, molecular biology, genetic, pathology, and treatment by searching for the following terms: "Epidemiology AND Natural History," "risk of hemorrhage," "intracranial hemorrhage," "diagnosis," "angiogenesis," "molecular genetics," "VEGF," "KRAS," "radiosurgery," "endovascular," "microsurgery," or "surgical resection." Our understanding of bAVMs has significantly evolved in recent years. The latest investigations have helped in defining some molecular pathways involved in the pathology of bAVM. Although there is still more to learn and discover, describing these pathways will allow the creation of targeted treatments that could improve the prognosis of patients with bAVMs.

Controlled arterial hypotension during resection of cerebral arteriovenous malformations

Background

Resection of cerebral arteriovenous malformations (AVM) is technically demanding because of size, eloquent location or diffuse nidus. Controlled arterial hypotension (CAH) could facilitate haemostasis. We performed a study to characterize the duration and degree of CAH and to investigate its association with blood loss and outcome.

Methods

We retrospectively analysed intraoperative arterial blood pressure of 56 patients that underwent AVM-resection performed by the same neurosurgeon between 2003 and 2012. Degree of CAH, AVM size, grading and neurological outcome were studied. Patients were divided into two groups, depending on whether CAH was performed (hypotension group) or not (control group).

Results

The hypotension group consisted of 28 patients, which presented with riskier to treat AVMs and a higher Spetzler-Martin grading. CAH was achieved by application of urapidil, increasing anaesthetic depth or a combination thereof. Systolic and mean arterial blood pressure were lowered to 82 ± 7 and 57 ± 7 mmHg, respectively, for a median duration of 58 min [25% percentile: 26 min.; 75% percentile: 107 min]. In the hypotension group, duration of surgery (4.4 ± 1.3 h) was significantly (p <  0.001) longer, and median blood loss (500 ml) was significantly (p = 0.002) higher than in the control group (3.3 ± 0.9 h and 200 ml, respectively). No case fatalities occurred. CAH was associated with a higher amount of postoperative neurological deficits.

Conclusions

Whether CAH caused neurological deficits or prevented worse outcomes could be clarified by a prospective randomised study, which is regarded as ethically problematic in the context of bleeding. CAH should only be used after strict indication and should be applied as mild and short as possible.

Chinese Cerebrovascular Neurosurgery Society and Chinese Interventional & Hybrid Operation Society, of Chinese Stroke Association Clinical Practice Guidelines for Management of Brain Arteriovenous Malformations in Eloquent Areas

Aim: The aim of this guideline is to present current and comprehensive recommendations for the management of brain arteriovenous malformations (bAVMs) located in eloquent areas. Methods: An extended literature search on MEDLINE was performed between Jan 1970 and May 2020. Eloquence-related literature was further screened and interpreted in different subcategories of this guideline. The writing group discussed narrative text and recommendations through group meetings and online video conferences. Recommendations followed the Applying Classification of Recommendations and Level of Evidence proposed by the American Heart Association/American Stroke Association. Prerelease review of the draft guideline was performed by four expert peer reviewers and by the members of Chinese Stroke Association. Results: In total, 809 out of 2,493 publications were identified to be related to eloquent structure or neurological functions of bAVMs. Three-hundred and forty-one publications were comprehensively interpreted and cited by this guideline. Evidence-based guidelines were presented for the clinical evaluation and treatment of bAVMs with eloquence involved. Topics focused on neuroanatomy of activated eloquent structure, functional neuroimaging, neurological assessment, indication, and recommendations of different therapeutic managements. Fifty-nine recommendations were summarized, including 20 in Class I, 30 in Class IIa, 9 in Class IIb, and 2 in Class III. Conclusions: The management of eloquent bAVMs remains challenging. With the evolutionary understanding of eloquent areas, the guideline highlights the assessment of eloquent bAVMs, and a strategy for decision-making in the management of eloquent bAVMs.

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

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

An Update on Medications for Brain Arteriovenous Malformations

Despite a variety of treatment options for brain arteriovenous malformations (bAVMs), many lesions remain challenging to treat and present significant ongoing risk for hemorrhage. In Vitro investigations have recently led to a greater understanding of the formation, growth, and rupture of bAVMs. This has, in turn, led to the development of therapeutic targets for medications for bAVMs, some of which have begun testing in clinical trials in humans. These include bevacizumab, targeting the vascular endothelial growth factor driven angiogenic pathway; thalidomide or lenalidomide, targeting blood-brain barrier impairment; and doxycycline, targeting matrix metalloproteinase overexpression. A variety of other medications appear promising but either requires adaptation from other disease states or development from early bench studies into the clinical realm. This review aims to provide an overview of the current state of development of medications targeting bAVMs and to highlight their likely applications in the future.

Brain arteriovenous malformations

Brain arteriovenous malformations are an important cause of intracerebral hemorrhage in the young. Ruptured AVM's are often treated, as the risk of rebleeding is high. The treatment of incidentally discovered, unruptured AVMs is controversial as the morbidity and mortality of treatment may exceed that of the AVM's natural history. Management is multimodal and includes observation with follow up, as well as microsurgical resection, endovascular embolization, and stereotactic radiosurgery. Multidisciplinary teams are important in evaluating patients for treatment. The goal of treatment is complete AVM obliteration while preserving neurologic function.

Living with a Brain AVM: A Quality of Life Assessment

BACKGROUND AND PURPOSE

Brain arteriovenous malformations (AVM) are uncommon vascular lesions with the risk of hemorrhage, epileptic seizures, neurological deficits, and headache. Comparing the risks of the natural history and that of preventive treatment, a recent study has found observation more beneficial than treatment for unruptured AVMs. This study, however, did not consider the long-term impact of carrying a brain AVM on everyday activities. In this study we analyzed the Quality Of Life (QOL) of patients with untreated AVMs, a measure increasingly used in clinical trials to asses this kind of impact.

METHODS

We enrolled 36 patients with unruptured, untreated brain AVM from our hospital database and measured their QOL retrospectively using the EQ-5D-5L questionnaire. As a control group we used the results of the Research Report, a nationwide study based on the quality of life of 5534 healthy Hungarians in 2002. Due to the low number of cases, statistical analysis could not be made.

RESULTS

Headache proved to be the most common AVM-related sign in our cohort (40%, n = 17), with a female predominance; neurological deficit was detected in 33% (n = 14), while epileptic seizures occurred in 26% (n = 11), more commonly affecting male subjects. Anxiety and discomfort seemed to be the most prevalent influencing factors on QOL, especially in the youngest age group (18-34 years). Female subjects showed a greater dependence than men in all age groups, though males had a more significant impairment in their usual activities. Older patients were affected more significantly in their self-care and usual activities compared with the younger population.

CONCLUSIONS

Untreated AVMs have a significant negative impact on patients carrying unruptured brain AVMs, as proved by QOL assessment. Beside neurological deficits, this impact should also be considered in the therapeutic decision.

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.

Characteristics and Long-Term Outcome of 127 Children With Cerebral Arteriovenous Malformations

BACKGROUND

Population-based long-term data on pediatric patients with cerebral arteriovenous malformations (AVMs) are limited.

OBJECTIVE

To clarify the characteristics and long-term outcome of pediatric patients with AVM.

METHODS

A retrospective analysis was performed on 805 consecutive brain AVM patients admitted to a single center between 1942 and 2014. The patients were defined as children if they were under 18 yr at admission. Children were compared to an adult cohort. Changing patterns of presentation were also analyzed by decades of admission.

RESULTS

The patients comprised 127 children with a mean age of 12 yr. The mean follow-up time was 21 yr (range 0-62). Children presented more often with intracerebral hemorrhage (ICH) but less often with epilepsy than adults. Basal ganglia, cerebellar, and posterior paracallosal AVMs were more common in pediatric than in adult patients. Frontal and temporal AVMs, in contrast, were more common in adult than in pediatric patients. As the number of incidentally and epilepsy-diagnosed AVMs increased, ICH rates dropped in both cohorts. In total, 22 (82%) pediatric and 108 (39%) adult deaths were assessed as AVM related. After multivariate analysis, small AVM size and surgical treatment correlated with a favorable long-term outcome.

CONCLUSION

Hemorrhagic presentation was more common in children than in adults. This was also reflected as lower prevalence of epileptic presentation in the pediatric cohort. Lobar and cortical AVM locations were less frequent, whereas deep and cerebellar AVMs were more common in children. Hemorrhagic presentation correlated negatively with incidentally and epilepsy-diagnosed AVMs. In children, AVM was a major cause of death, but in adults, other factors contributed more commonly to mortality.

Silent MRA: arterial spin labeling magnetic resonant angiography with ultra-short time echo assessing cerebral arteriovenous malformation

PURPOSE

MR angiography using the silent MR angiography algorithm (silent MRA), which combines arterial spin labeling and an ultrashort time echo, has not been used for the evaluation of cerebral arteriovenous malformations (CAVMs). We aimed to determine the usefulness of silent MRA for the evaluation of CAVMs.

METHODS

Twenty-nine CAVMs of 28 consecutive patients diagnosed by 4D CT angiography or digital subtraction angiography, who underwent both time-of-flight (TOF) MRA and silent MRA, were enrolled. Two observers independently assessed the TOF-MRA and silent MRA images of CAVMs. Micro AVM was defined as AVM with a nidus diameter less than 10 mm. The detection rate, visualization of the components, and accuracy of Spetzler-Martin grade were evaluated with statistical software R.

RESULTS

For all 29 CAVMs, 23 (79%) lesions were detected for TOF-MRA and all for silent MRA. Of 10 micro AVMs, only 4 (40%) lesions were detectable on TOF-MRA and all (100%) on silent MRA. The visibility of the nidus and drainer was significantly better for silent MRA than TOF-MRA (p < 0.001), while there was no significant difference in the feeder between the two sequences. The accuracy rates of the Spetzler-Martin grade for the TOF and silent MRA were 38% (11/29) and 79.3% (23/29), respectively (p < 0.001).

CONCLUSIONS

Silent MRA is useful for evaluating CAVM components and detecting micro AVM.

Curative treatment for low-grade arteriovenous malformations

Background

Spetzler-Martin (SM) grade I-II (low-grade) arteriovenous malformations (AVMs) are often considered safe for microsurgery or radiosurgery. The adjunctive use of preoperative embolization to reduce surgical risk in these AVMs remains controversial.

Objective

To assess the safety of combined treatment of grade I-II AVMs with preoperative embolization followed by surgical resection or radiosurgery, and determine the long-term functional outcomes.

Methods

With institutional review board approval, a retrospective analysis was carried out on patients with ruptured and unruptured SM I-II AVMs between 2002 and 2017. Details of the endovascular procedures, including number of arteries supplying the AVM, number of branches embolized, embolic agent(s) used, and complications were studied. Baseline clinical and imaging characteristics were compared. Functional status using the modified Rankin Scale (mRS) before and after endovascular and microsurgical treatments was compared.

Results

258 SM I-II AVMs (36% SM I, 64% SM II) were identified in patients with a mean age of 38 ± 17 years. 48% presented with hemorrhage, 21% with seizure, 16% with headache, 10% with no symptoms, and 5% with clinical deficits. 90 patients (68%) in the unruptured group and 74 patients (59%) in the ruptured group underwent presurgical embolization (p = 0.0013). The mean number of arteries supplying the AVM was 1.44 and 1.41 in the unruptured and ruptured groups, respectively (p = 0.75). The mean number of arteries embolized was 2.51 in the unruptured group and 1.82 in the ruptured group (p = 0.003). n-Butyl cyanoacrylate and Onyx were the two most commonly used embolic agents. Four complications were seen in four patients (4/164 patients embolized): two peri-/postprocedural hemorrhage, one dissection, and one infarct. All patients undergoing surgery had a complete cure on postoperative angiography. Patients were followed up for a mean of 55 months. Good long-term outcomes (mRS score ≤ 2) were seen in 92.5% of patients with unruptured AVMs and 88.0% of those with ruptured AVMs. Permanent neurological morbidity occurred in 1.2%.

Conclusions

Curative treatment of SM I-II AVMs can be performed using endovascular embolization with microsurgical resection or radiosurgery in selected cases, with very low morbidity and high cure rates. Compared with other published series, these outcomes suggest that preoperative embolization is a safe and effective adjunct to definitive surgical treatment. Long-term follow-up showed that patients with low-grade AVMs undergoing surgical resection or radiosurgery have good functional outcomes.

The factors associated with hemorrhagic presentation in children with untreated brain arteriovenous malformation: a meta-analysis

OBJECTIVE Rupture of arteriovenous malformations (AVMs) would result in high mortality and prevalence of disability in pediatric patients. Decisions regarding the treatment of AVMs need to weigh the risk of rupture over the course of their natural history against the possibility of creating a lesion during treatment. Multiple factors have been proposed to predict hemorrhagic presentation of pediatric patients with AVMs. The aim of this meta-analysis was to evaluate the predictors of hemorrhagic presentation in pediatric patients with AVMs. METHODS The authors searched the PubMed and EMBASE databases. Studies reporting the predictors of hemorrhagic presentation in children with untreated brain AVMs were included. The predictive ability of identified predictors was assessed by odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS A higher risk of hemorrhagic presentation was found in AVMs with smaller size (< 3 cm, OR 2.97, 95% CI 1.94–4.54, p < 0.00001), deep venous drainage (OR 2.28, 95% CI 1.55–3.36, p < 0.0001), a single draining vein (OR 2.23, 95% CI 1.27–3.92, p = 0.005), a single feeder (OR 3.72, 95% CI 1.31–10.62, p = 0.01), a deep location (OR 1.82, 95% CI 1.22–2.72, p = 0.004), an infratentorial location (OR 2.25, 95% CI 1.19–4.26, p = 0.01), and diffuse morphology (OR 8.94, 95% CI 3.01–26.55, p < 0.0001). In addition, the AVMs with draining vein ectasia (OR 0.35, 95% CI 0.13–0.97, p = 0.04) and high Spetzler-Martin (SM) grade (OR 0.53, 95% CI 0.36–0.78, p = 0.001) had a lower risk of hemorrhagic presentation in pediatric patients. CONCLUSIONS Smaller AVMs, deep venous drainage, a single draining vein, a single feeder, deep/infratentorial location, diffuse morphology, and high SM grade were identified as positive predictors for hemorrhagic presentation. Particularly, patients with diffuse AVMs have a higher risk of hemorrhagic presentation than other factors and may need active treatments. However, factors such as age, sex, draining vein stenosis, and associated aneurysms were not associated with hemorrhagic presentation. ABBREVIATIONS AVM = arteriovenous malformation; CI = confidence interval; NOS = Newcastle-Ottawa Scale; OR = odds ratio; SM = Spetzler-Martin.

Single-stage planning for total cure of grade III-V brain arteriovenous malformations by embolization alone or in combination with microsurgical resection

PURPOSE

There are no established guidelines for treatment of Spetzler-Martin grade III-V brain arteriovenous malformations (bAVMs). The purpose of this study is to report our institutional experience in total obliteration/eradication of grade III-V bAVMs by single-stage planning of embolization combined with microsurgical resection when necessary.

METHODS

All patients harboring Spetzler-Martin (S-M) grade III-V bAVMs treated with single-stage planning between January 2006 and January 2018 were retrospectively reviewed. This treatment paradigm is applicable only to surgically accessible bAVMs and does not include deep-seated bAVMs. Indications for treatment, clinical presentation, imaging characteristics, and treatment outcomes were analyzed. Outcomes were assessed based on modified Rankin Scale.

RESULTS

A total of 31 patients were identified. Seventeen patients (54.8%) presented with hemorrhage, 10 (32.3%) with seizures, 3 (9.7%) with headaches, and 1 (3.2%) with progressive neurological deficit. Based on S-M grading system, 25 patients (80.6%) harbored grade III bAVM, 5 patients had grade IV bAVMs (16.1%), and 1 patient (3.2%) had a grade V bAVM. There were no treatment-related complications in 24/31 (77.4%) patients. Of the total of seven patients with complications, four patients had clinical deterioration. The long-term (> 6-month), non-disabling morbidity (mRS ≤ 2) rate was 6.5%. The long-term, disabling morbidity rate was 3.2% with a mortality of 3.2%. Complete angiographic obliteration was achieved in 30/31 (96.8%) patients.

CONCLUSION

Single-stage treatment strategy can be considered as an alternative to multistage embolization prior to surgery in grade III-V bAVMs. In this study, a high rate of total obliteration with relatively low rates of permanent morbidity and mortality was achieved.

Treatment decision for occipital arteriovenous malformations (AVMs) to achieve hemorrhagic control while maximizing visual preservation: Our experience and review of literature

Despite concern of hemorrhagic risk, patients with occipital AVMs are at significant risk for visual disturbances after treatment. We aim to characterize the hemorrhage risk and visual disturbance in occipital AVMs patients from our experience and literature review. We performed retrospective review of occipital AVM patients seen at our institution from 1990 to 2015. Patient characteristics were compared using multivariable logistic regression with follow-up visual disturbance as the outcome. We also systematically reviewed the PubMed database for English literature describing occipital AVMs (with exclusion of case reports). Ninety-seven patients satisfied inclusion criteria for our study. Mean age was 34.9 ± 16.4 years, with 50.5% male. Thirty-one (32.0%) presented with hemorrhage, and 32 (33.0%) presented with visual disturbance. Average AVM size was 4.0 ± 2.5 cm. Twenty-five (25.8%) were conservatively managed, 13 (13.4%) underwent surgery, and the rest were managed by radiosurgery (52.6%) or embolization (8.2%), with an obliteration rate of 38.9% in treated patients. During average follow-up of 5.4 years, 6 patients (6.7%) hemorrhaged yielding an annual hemorrhage rate of 1.2% for all patients, and 0.0% for surgically-treated patients. Thirty-seven (38.3%) patients experienced visual disturbance in some capacity, nineteen (21.1%) had de novo visual disturbance, fourteen of which were surgically treated patients (19.4%). Multivariable analysis reveals visual disturbance at presentation (p = .012) and microsurgery (p = .047) are significantly predictors of follow-up visual disturbance. While hemorrhage control remains the primary goal of AVM treatment, visual preservation in occipital AVMs is also a major concern. Recommending patients for microsurgery should be weighed carefully and individualized as it bears the highest risk of visual field disturbance despite most optimal hemorrhage control.

European consensus conference on unruptured brain AVMs treatment (Supported by EANS, ESMINT, EGKS, and SINCH)

In December of 2016, a Consensus Conference on unruptured AVM treatment, involving 24 members of the three European societies dealing with the treatment of cerebral AVMs (EANS, ESMINT, and EGKS) was held in Milan, Italy. The panel made the following statements and general recommendations: (1) Brain arteriovenous malformation (AVM) is a complex disease associated with potentially severe natural history; (2) The results of a randomized trial (ARUBA) cannot be applied equally for all unruptured brain arteriovenous malformation (uBAVM) and for all treatment modalities; (3) Considering the multiple treatment modalities available, patients with uBAVMs should be evaluated by an interdisciplinary neurovascular team consisting of neurosurgeons, neurointerventionalists, radiosurgeons, and neurologists experienced in the diagnosis and treatment of brain AVM; (4) Balancing the risk of hemorrhage and the associated restrictions of everyday activities related to untreated unruptured AVMs against the risk of treatment, there are sufficient indications to treat unruptured AVMs grade 1 and 2 (Spetzler-Martin); (5) There may be indications for treating patients with higher grades, based on a case-to-case consensus decision of the experienced team; (6) If treatment is indicated, the primary strategy should be defined by the multidisciplinary team prior to the beginning of the treatment and should aim at complete eradication of the uBAVM; (7) After having considered the pros and cons of a randomized trial vs. a registry, the panel proposed a prospective European Multidisciplinary Registry.

Clinical Experience and Results of Microsurgical Resection of Arterioveonous Malformation in the Presence of Space-Occupying Intracerebral Hematoma

BACKGROUND: Management of ruptured arteriovenous malformations (AVMs) with a mass-producing intracerebral hematoma (ICH) represents a surgical dilemma.

OBJECTIVE: To evaluate the clinical outcome and obliteration rates of microsurgical resection of AVM when performed concomitantly with evacuation of an associated space-occupying ICH.

METHODS: Data of patients with AVM were collected prospectively. Cases were identified in which an AVM was resected and an associated space-occupying ICH was evacuated at the same time, and divided into “group 1,” in which the surgery was performed acutely within 48 h of presentation (secondary to elevated intracranial pressure); and “group 2,” in which selected patients were operated upon in the presence of a liquefying ICH in the “subacute” stage. Clinical outcomes were assessed using the modified Rankin Scale, with a score of 0 to 2 considered a good outcome. Obliteration rates were assessed using postoperative angiography.

RESULTS: From 2001 to 2015, 131 patients underwent microsurgical resection of an AVM, of which 65 cases were included. In “group 1” (n = 21; Spetzler-Ponce class A = 13, class B = 5, and class C = 3), 11 of 21 (52%) had a good outcome and in 18 of 19 (95%) of those who had a postoperative angiogram the AVMs were completely obliterated. In “group 2” (n = 44; Spetzler-Ponce class A = 33, class B = 9, and class C = 2), 31 of 44 (93%) had a good outcome and 42 of 44 (95%) were obliterated with a single procedure. For supratentorial AVMs, the ICH cavity was utilized to provide an operative trajectory to a deep AVM in 11 cases, and in 26 cases the ICH cavity was deep to the AVM and hence facilitated the deep dissection of the nidus.

CONCLUSION: In selected patients the presence of a liquefying ICH cavity may facilitate the resection of AVMs when performed in the subacute stage resulting in a good neurological outcome and high obliteration rate.

The natural history of cerebral arteriovenous malformations

Cerebral arteriovenous malformations (AVMs) are composed of a complex tangle of abnormal arteries and veins and are a significant source of cerebral hemorrhage and consequent morbidity and mortality in young adults, representing a diagnostic and therapeutic challenge. Current natural-history studies of cerebral AVMs report overall annual rates of 1% and 3% for the risk of epilepsy and hemorrhage, respectively. Unruptured AVMs have an annual hemorrhage rate of 2.2% while ruptured lesions have an annual hemorrhage rate of 4.5%. These hemorrhage rates are can change over time, particularly for hemorrhagic lesions, with the rebleed rate ranging from 6% to 15.8% in the first year after rupture across several studies. Besides hemorrhage, other significant risk factors for AVM hemorrhage include deep location, deep venous drainage, associated aneurysms, and pregnancy. Other factors include patient age, sex, and small AVM size, which are not currently considered significant risk factors for AVM hemorrhage. In addition to hemorrhage risk and seizure risk, the natural history of an AVM also encompasses the daily psychologic burden that a patient must endure knowing that he or she possesses an untreated AVM. This chapter reviews the epidemiology, clinical features, and natural history of cerebral AVMs.

Predictors for occlusion of cerebral AVMs following radiation therapy : Radiation dose and prior embolization, but not Spetzler-Martin grade

BACKGROUND

Intracranial arteriovenous malformations (AVMs) may show a harmful development. AVMs are treated by surgery, embolization, or radiation therapy.

OBJECTIVE

This study investigated obliteration rates and side effects in patients with AVMs treated by radiation therapy.

METHODS

A total of 40 cases treated between 2005 and 2013 were analyzed. Single-dose stereotactic radiosurgery (SRS) was received by 13 patients and 27 received hypofractionated stereotactic radiation therapy (HSRT). In 20 patients, endovascular embolization had been performed prior to irradiation and 24 patients (60 %) had a history of previous intracranial hemorrhage.

RESULTS

Treatment resulted in complete obliteration (CO) in 23/40 cases and partial obliteration in 8/40. CO was achieved in 85 % of patients receiving SRS compared to 44 % of those receiving HSRT. In the HSRT group, a first indication of an influence of AVM volume on obliteration rate was found. Equivalent 2 Gy fraction doses (EQD2) >70 Gy showed an obliteration rate of 50 %. Prior embolization was significantly associated with a higher portion of CO (p = 0.032). Median latency period (24.2 vs. 26 months) until CO was similar in both groups (SRS vs. HSRT). The rate of intracranial hemorrhage in patients with no prior bleeding events was 0 %.

CONCLUSION

Excellent obliteration rates were achieved by SRS. Consistent with the literature, this data analysis suggests that the results of HSRT are volume-dependent. Furthermore, regimens with EQD2 doses >70 Gy appear more likely to achieve obliteration than schemes with lower doses. The findings indicate that radiation therapy does not increase the risk of bleeding. Prior embolization may have a good prognostic impact.

Long-term hemorrhagic risk in pediatric patients with arteriovenous malformations

OBJECTIVE Compared with the general population, the specific natural history of arteriovenous malformations (AVMs) in pediatric patients is less well understood. Furthermore, few pediatric studies have compared posttreatment hemorrhagic risk and functional outcome across different treatment modalities. The objective of this study was to elucidate these points. METHODS The authors retrospectively reviewed all pediatric patients with AVMs evaluated at their institution between 1990 and 2013. The AVM natural history was represented by hemorrhagic risk during the observation period. For treated patients, the observation period was defined as the interval between diagnosis and treatment. Posttreatment hemorrhagic risk and functional outcomes were also assessed. RESULTS A total of 124 pediatric patients with AVMs were evaluated, and 90 patients (72.6%) were retained through follow-up. The average patient age was 13.3 ± 3.8 years, with a mean follow-up period of 9.95 years. The overall AVM obliteration rate was 59.7%. Radiosurgery had an obliteration rate of 49.0%. Thirteen patients were managed conservatively. Four patients under observation hemorrhaged during a total interval of 429.4 patient-years, translating to an annual risk of 0.9%. Posttreatment hemorrhagic risk by treatment modalities were categorized as follows: surgery ± embolization (0.0%), radiosurgery ± embolization (0.8%), embolization alone (2.8%), surgery + radiosurgery ± embolization (3.5%), and observation (0.8%). A significantly higher risk of posttreatment hemorrhage was observed for patients with hemorrhagic presentation (p = 0.043) in multivariate analysis. Seizure presentation, frontal lobe location, nonheadache presentation, and treatment modality were significantly associated with increased risk of poor functional outcomes. CONCLUSIONS In this study of pediatric patients with AVMs, the natural history of hemorrhage was relatively low at 0.9%. Resection remained the optimal management for hemorrhage control and functional outcome perseverance in these pediatric patients with AVMs. AVM obliteration is a valid treatment goal, especially for patients with ruptured presentation, to prevent further hemorrhages later in life.

Microsurgery for cerebral arteriovenous malformations: subgroup outcomes in a consecutive series of 288 cases

OBJECTIVE The objective of this study was to review the outcomes after microsurgical resection of cerebral arteriovenous malformations (AVMs) from a consecutive single-surgeon series. Clinical and imaging data were analyzed to address the following questions concerning AVM treatment in the post-ARUBA (A Randomized Trial of Unruptured Brain Arteriovenous Malformations) era. 1) Are the patients who present with unruptured or ruptured AVMs doing better at long-term follow-up? 2) Is the differentiation between Ponce Class A (Spetzler-Martin Grade I and II) patients versus Ponce Class B and C patients (Spetzler-Martin Grade III and IV) meaningful and applicable to surgical practice? 3) How did the ARUBA-eligible patients of this surgical series compare with the results reported in ARUBA? METHODS Two hundred eighty-eight patients with cerebral AVMs underwent microsurgical resection between 1983 and 2012 performed by the same surgeon (J.S.). This is a prospective case collection study that represents a consecutive series. The results are based on prospectively collected, early-outcome data that were supplemented by retrospectively collected, follow-up data for 94% of those cases. The analyzed data included the initial presentation, Spetzler-Martin grade, obliteration rates, surgical and neurological complications, and frequency of pretreatment with embolization or radiosurgery. The total cohort was compared using "small-AVM," Spetzler-Martin Grade I and II, and ARUBA-eligible AVM subgroups. RESULTS The initial presentation was hemorrhage in 50.0% and seizures in 43.1% of patients. The series included 53 Spetzler-Martin Grade I (18.4%), 114 Spetzler-Martin Grade II (39.6%), 90 Spetzler-Martin Grade III (31.3%), 28 Spetzler-Martin Grade IV (9.7%), and 3 Spetzler-Martin Grade V (1.0%) AVMs. There were 144 unruptured and 104 ARUBA-eligible cases. Preembolization was used in 39 cases (13.5%). The occlusion rates for the total series and small AVM subgroup were 99% and 98.7%, respectively. The mean follow-up duration was 64 months. Early neurological deterioration was seen in 39.2% of patients, of which 12.2% had permanent and 5.6% had permanent significant deficits, and the mortality rate was 1.7% (n = 5). Outcome was better for patients with AVMs smaller than 3 cm (permanent deficit in 7.8% and permanent significant deficit in 3.2% of patients) and Ponce Class A status (permanent deficit in 7.8% and significant deficit in 3.2% of patients). Unruptured AVMs showed slightly higher new deficit rates (but 0 instances of mortality) among all cases, and in the small AVM and Ponce Class A subgroups. Unruptured Spetzler-Martin Grade I and II lesions had the best outcome (1.8% permanent significant deficit), and ARUBA-eligible Spetzler-Martin Grade I and II lesions had a slightly higher rate of permanent significant deficits (3.2%). CONCLUSIONS Microsurgery has a very high cure rate. Focusing microsurgical AVM resection on unruptured lesions smaller than 3 cm or on Spetzler-Martin Grade I and II lesions is a good strategy for minimizing long-term morbidity. Well-selected microsurgical cases lead to better outcomes than with multimodal interventions, as in the ARUBA treatment arm, or conservative treatment alone. Long-term prospective data collection is valuable.

Demographic distribution of hospital admissions for brain arteriovenous malformations in Germany--estimation of the natural course with the big-data approach

BACKGROUND

Estimation of the natural history of arteriovenous malformations based on short-term observation is potentially biased by multiple factors. Retrieval of demographic information of all AVM patients of national data pools and comparison with the national demographic profile might be another way to approach the natural history.

MATERIALS AND METHODS

Upon request, the German Federal Statistical Office provided the numbers of patients admitted in Germany from 2009 through 2013 with ICD Q28.2 (brain AVM) as primary discharge diagnosis, and the corresponding age distribution. Age-related admission rates of AVM were calculated by comparison with the German demographic distribution.

RESULTS

A total of 6527 patients were hospitalized from 2009-2013 with brain AVM (Q28.2) as the principal diagnosis. Age-specific admission rate during the first year of life was high with 19.0/100,000 during the 5-year study period, corresponding to a yearly admission rate of 3.8 per 100,000 babies. Apart from the high admission rate during the first year of life, the admission rate was low, but steadily increasing during first decades of life reaching a plateau with 11.1/100,000 in the age group 30-34 years, corresponding to an annual admission rate of 2.2/100,000. After the age of 30-34 years, admission rates decreased continuously, reaching 0 in the age group 90-95 years. The lifetime risk of admission in terms of admission per 100,000 age-matched people was calculated by retrograde integration of the admission rates. At the age of 1 year, the cumulative number of future admissions for AVM during lifetime amounted to 131.3/100,000 children. For the older age groups, the chance of future admission for AVM decreased as expected, reaching 43.8/100,000 by the age of 50 and 0 by the age of 90.

CONCLUSIONS

Despite some open issues, the current data suggests that achieving old age with an untreated brain AVM is unlikely. Furthermore, the data support the concept that most brain AVMs are not necessarily a congenital entity but develop during the first decades of life.

Multimodality Management of Cerebral Arteriovenous Malformations with Special Reference to AVM-Related Hemorrhages During Ongoing Staged Treatment

In this study we report and analyze the results of a multimodality management concept for intracranial arteriovenous malformations (AVMs), including microsurgery, embolization, and gamma knife radiosurgery. The study population consists of a consecutive series of 294 patients treated for 304 intracranial AVMs over a 10-year period.

Microsurgical resection of Spetzler-Martin grades 1 and 2 unruptured brain arteriovenous malformations results in lower long-term morbidity and loss of quality-adjusted life-years (QALY) than conservative management--results of a single group series

BACKGROUND

The therapeutic benefits of microsurgery for unruptured brain AVM remain unclear.

METHODS

A series of 97 microsurgically resected unruptured brain AVM was analyzed in terms of postoperative morbidity and lifetime loss of quality-adjusted life-years (QALY). For comparison, the natural risk of becoming disabled was modeled on the basis of published data.

RESULTS

Discharge morbidity was recorded in 11 of the 69 of Spetzler-Martin (SM) grade 1 and 2 AVMs (16 %), eight of 22 (36 %) grade 3, and four of six grade 4 (67 %), permanent morbidity >mRS 1 in 3 (4.3 %) grade 1 and 2, four (18 %) grade 3, and three (50 %) grade 4. Treatment inflicted loss of QALY amounted to 0.5 years for SM grade 1-2, 2.5 years grade 3, 7.3 years for grade 4. For the SM grades 1 and 2, the treatment-related loss of 0.5 QALY was met by the natural course after 2.7-4.3 years. For the Spetzler-Martin grades 3 and 4, the treatment-induced loss QALY was not met by the natural risk within a foreseeable time. Permanent morbidity and treatment inflicted loss of QALY of patients younger than 39 years was lower than that of older patients (7 vs. 15 % and 1.0 vs. 2.1 QALY).

CONCLUSIONS

Microsurgically managed SM grades 1 and 2 fared better than the modeled natural course but grades 3 and 4 AVM did not benefit from surgery. Younger patients appear to fare more favorably than older patients.

Brain arteriovenous malformations

An arteriovenous malformation is a tangle of dysplastic vessels (nidus) fed by arteries and drained by veins without intervening capillaries, forming a high-flow, low-resistance shunt between the arterial and venous systems. Arteriovenous malformations in the brain have a low estimated prevalence but are an important cause of intracerebral haemorrhage in young adults. For previously unruptured malformations, bleeding rates are approximately 1% per year. Once ruptured, the subsequent risk increases fivefold, depending on associated aneurysms, deep locations, deep drainage and increasing age. Recent findings from novel animal models and genetic studies suggest that arteriovenous malformations, which were long considered congenital, arise from aberrant vasculogenesis, genetic mutations and/or angiogenesis after injury. The phenotypical characteristics of arteriovenous malformations differ among age groups, with fistulous lesions in children and nidal lesions in adults. Diagnosis mainly involves imaging techniques, including CT, MRI and angiography. Management includes observation, microsurgical resection, endovascular embolization and stereotactic radiosurgery, alone or in any combination. There is little consensus on how to manage patients with unruptured malformations; recent studies have shown that patients managed medically fared better than those with intervention at short-term follow-up. By contrast, interventional treatment is preferred following a ruptured malformation to prevent rehaemorrhage. Management continues to evolve as new mechanistic discoveries and reliable animal models raise the possibility of developing drugs that might prevent the formation of arteriovenous malformations, induce obliteration and/or stabilize vessels to reduce rupture risk. For an illustrated summary of this Primer, visit: http://go.nature.com/TMoAdn.

Management of posterior fossa arteriovenous malformations

Background:

Posterior fossa arteriovenous malformations (AVMs) are rare vascular lesions, representing 7–15% of all intracranial AVMs. Although less frequent than supratentorial AVMs, they present higher rupture, morbidity, and mortality rates. Microsurgery, radiosurgery, and endovascular neurosurgery are treatment options for obliteration of those lesions. In this paper, we present a critical review of the literature about the management of posterior fossa AVM.

Methods:

A MEDLINE-based search of articles published between January 1960 and January 2014 was performed. The search terms: “Posterior fossa arteriovenous malformation,” “microsurgery,” “radiosurgery,” and “endovascular” were used to identify the articles.

Results:

Current data supports the role of microsurgery as the gold standard treatment for cerebellar AVMs. Brainstem AVMs are usually managed with radiotherapy and endovascular therapy; microsurgery is considered in cases of pial brainstem AVMs.

Conclusions:

Succsseful treatment of posterior fossa AVMs depend on an integrated work of neurosurgeons, radiosurgeons, and endovascular neurosurgery. Although the development of radiosurgery and endovascular techniques is remarkable, microsurgery remains as the gold standard treatment for most of those lesions.