The ARUBA trial: current status, future hopes

Comparative Study of Automated Algorithms for Brain Arteriovenous Malformation Nidus Extent Identification Using 3DRA

PURPOSE

When performing a brain arteriovenous malformation (bAVMs) intervention, computer-assisted analysis of bAVMs can aid clinicians in planning precise therapeutic alternatives. Therefore, we aim to assess currently available methods for bAVMs nidus extent identification over 3DRA. To this end, we establish a unified framework to contrast them over the same dataset, fully automatising the workflows.

MATERIALS AND METHODS

We retrospectively collected contrast-enhanced 3DRA scans of patients with bAVMs. A segmentation network was used to automatically acquire the brain vessels segmentation for each case. We applied the nidus extent identification algorithms over each of the segmentations, computing overlap measurements against manual nidus delineations.

RESULTS

We evaluated the methods over a private dataset with 22 3DRA scans of individuals with bAVMs. The best-performing alternatives resulted in [Formula: see text] and [Formula: see text] dice coefficient values.

CONCLUSIONS

The mathematical morphology-based approach showed higher robustness through inter-case variability. The skeleton-based approach leverages the skeleton topomorphology characteristics, while being highly sensitive to anatomical variations and the skeletonisation method employed. Overall, nidus extent identification algorithms are also limited by the quality of the raw volume, as the consequent imprecise vessel segmentation will hinder their results. Performance of the available alternatives remains subpar. This analysis allows for a better understanding of the current limitations.

National reduction in cerebral arteriovenous malformation treatment correlated with increased rupture incidence

BACKGROUND

Recently, there has been a shift in management of unruptured cerebral arteriovenous malformations (AVMs) following studies suggesting that medical management alone was superior to interventional therapy.

OBJECTIVE

To evaluate the influence of contemporary AVM management on AVM rupture patterns in the United States.

METHODS

154 297 AVM admissions were identified between 2003 and 2017 in the National Inpatient Sample. Annual AVM intervention and rupture rates were computed and multivariable logistic regression assessed the likelihood of AVM intervention pre- and post-2014. Segmented regression identified significant change points and fitted segmented linear models for annual intervention and rupture rates. Correlation coefficients assessed the relationship between annual AVM intervention and rupture rates.

RESULTS

For unruptured AVMs, intervention likelihood and proportion decreased after 2014 (28.1% to 22.3%, p<0.0001; adjusted OR=0.857, 95% CI 0.751 to 0.977, p=0.02). Ruptured AVM admissions increased from 14.7% to 18.6% after 2014 (p<0.0001). Between 2003 and 2017, segmented linear regression identified one significant change point in intervention rate between 2014 and 2015. Average annual percent change for rupture incidence and intervention rate increased by 0.49% (p=0.0001) and decreased by 1.17% (p=0.0001), respectively. Annual AVM intervention rates were inversely correlated with annual AVM rupture incidence (Pearson coefficient=-0.82, p=0.0002). In 2017, the annual AVM rupture rate (20.6%) surpassed the annual AVM intervention rate (19.7%).

CONCLUSIONS

After 2014, the likelihood of intervention for unruptured AVMs decreased while the incidence of ruptured AVMs increased. These findings suggest that fewer unruptured AVM treatments may lead to increases in AVM rupture incidence.

Ruptured bilateral brain arteriovenous malformations in a young woman with early pregnancy: a case report

BACKGROUND

Brain arteriovenous malformations (AVMs) are rare congenital developmental vascular lesions, and often presents with symptoms upon rupture. The controversy exists as to whether pregnancy confers an increased risk of intracranial hemorrhage. The diagnosis of brain AVMs, in the absence of brain imaging, is challenging in resource-limited settings, particularly in sub-Saharan Africa.

CASE PRESENTATION

A 22-year old black African woman, primigravida at 14 weeks of gestation, presented with a history of persistent throbbing headache which was treated at primary health care facilities with analgesics and anti-migraine medications without relief. She later developed severe headache 2 weeks prior to admission and one-day history of serial partial generalized tonic-clonic seizures which were followed by post-ictal confusion and persistent right upper limb weakness. Initial evaluation revealed her to be pregnant and she later underwent a brain magnetic resonance angiography (MRA) at a university teaching hospital which revealed bleeding bilateral parietal AMVs with intracerebral haematoma and associated perilesional vasogenic oedema. The patient was managed conservatively using antifibrinolytic drugs and prophylactic anti-seizure drugs. Seven months later, she underwent a control brain MRA which revealed resolution of intracranial haematoma and associated vasogenic oedema and had her seizures well controlled. The headache had subsided and the pregnancy was allowed to continue to term under close obstetric and neurological observation. On follow up visits she reported episodes of nasal bleeding which upon ENT examination revealed nasal AVMs, suggesting the diagnosis of hereditary hemorrhagic telangiectasia (HHT).

CONCLUSION

AVMs are rare but should prompt suspicion in young patients with atypical Central Nervous System (CNS) manifestations without evident underlying causes.

Cellular loci involved in the development of brain arteriovenous malformations

Brain arteriovenous malformations (bAVMs) are abnormal vessels that are prone to rupture, causing life-threatening intracranial bleeding. The mechanism of bAVM formation is poorly understood. Nevertheless, animal studies revealed that gene mutation in endothelial cells (ECs) and angiogenic stimulation are necessary for bAVM initiation. Evidence collected through analyzing bAVM specimens of human and mouse models indicate that cells other than ECs also are involved in bAVM pathogenesis. Both human and mouse bAVMs vessels showed lower mural cell-coverage, suggesting a role of pericytes and vascular smooth muscle cells (vSMCs) in bAVM pathogenesis. Perivascular astrocytes also are important in maintaining cerebral vascular function and take part in bAVM development. Furthermore, higher inflammatory cytokines in bAVM tissue and blood demonstrate the contribution of inflammatory cells in bAVM progression, and rupture. The goal of this paper is to provide our current understanding of the roles of different cellular loci in bAVM pathogenesis.

Impact of Pre-operative Embolization With Onyx for Brain Arteriovenous Malformation Surgery

Objective

To clarify the safety and efficacy of pre-operative embolization using Onyx liquid embolic agent (Onyx; ev3) compared with N-butyl cyanoacrylate (NBCA; Cordis Neurovascular, Inc.) or coils in cerebral arteriovenous malformation (AVM) surgery.

Methods

This was a retrospective review of a prospectively collected clinical database of brain AVMs treated at our institute from January 2005 to March 2021. A total of 38 consecutive patients who underwent AVM resection after pre-operative embolization were included. Based on pre-operative embolization materials, the patients were divided into the pre-Onyx group (n = 16), in which NBCA or coils were used for embolization, and the Onyx group (n = 22). Patient characteristics and treatment results were compared between the two groups.

Results

Patient characteristics were comparable between the two groups in terms of age, sex, and rupture status. While the Spetzler-Martin grade was also similar between the two groups, the location of the AVM nidus in the eloquent area was slightly higher in patients in the Onyx group (72.7%) than in patients in the pre-Onyx group (43.8%) (P = 0.09). The embolization rate was higher in the pre-Onyx group (mean: 63.0%; range: 12.7-100%) than in the Onyx group (mean: 50.0%; range: 15.8-100%), but the difference was not statistically significant (P = 0.06). The time needed for surgical removal was shorter in the Onyx group (mean: 354.8 min; range: 144-884 min) than in the pre-Onyx group (mean: 457.9 min; range: 240-1,294 min); however, this difference was not statistically significant (P = 0.13). The amount of intraoperative bleeding was significantly lower in the Onyx group (mean: 129.8 ml; range: 20-540 mL) than in the pre-Onyx group (mean: 448.8 mL; range: 120-1,550 ml) (P = 0.0008). The surgical complication rates were comparable between the two groups (pre-Onyx group, 18.8%; Onyx group, 4.5%; P = 0.29).

Conclusions

Pre-operative embolization with Onyx can significantly reduce the amount of intraoperative bleeding in AVM resection and may contribute to safe AVM surgery.

The role of mural cells in hemorrhage of brain arteriovenous malformation

Brain arteriovenous malformation (bAVM) is the most common cause of intracranial hemorrhage (ICH), particularly in young patients. However, the exact cause of bAVM bleeding and rupture is not yet fully understood. In bAVMs, blood bypasses the entire capillary bed and directly flows from arteries to veins. The vessel walls in bAVMs have structural defects, which impair vascular integrity. Mural cells are essential structural and functional components of blood vessels and play a critical role in maintaining vascular integrity. Changes in mural cell number and coverage have been implicated in bAVMs. In this review, we discussed the roles of mural cells in bAVM pathogenesis. We focused on 1) the recent advances in human and animal studies of bAVMs; 2) the importance of mural cells in vascular integrity; 3) the regulatory signaling pathways that regulate mural cell function. More specifically, the platelet-derived growth factor-B (PDGF-B)/PDGF receptor-β (PDGFR-β), EphrinB2/EphB4, and angiopoietins/tie2 signaling pathways that regulate mural cell-recruitment during vascular remodeling were discussed in detail.

Intermediate-grade brain arteriovenous malformations and the boundary of operability using the supplemented Spetzler-Martin grading system

OBJECTIVE

Supplemented Spetzler-Martin grading (Supp-SM), which is the combination of Spetzler-Martin and Lawton-Young grades, was validated as being more accurate than stand-alone Spetzler-Martin grading, but an operability cutoff was not established. In this study, the authors surgically treated intermediate-grade AVMs to provide prognostic factors for neurological outcomes and to define AVMs at the boundary of operability.

METHODS

Surgically treated Supp-SM intermediate-grade (5, 6, and 7) AVMs were analyzed from 2011 to 2018 at two medical centers. Worsened neurological outcomes were defined as increased modified Rankin Scale (mRS) scores on postoperative examinations. A second analysis of 2000-2011 data for Supp-SM grade 6 and 7 AVMs was performed to determine the subtypes with improved or unchanged outcomes. Patients were separated into three groups based on nidus size (S1: < 3 cm, S2: 3-6 cm, S3: > 6 cm) and age (A1: < 20 years, A2: 20-40 years, A3: > 40 years), followed by any combination of the combined supplemented grade: low risk (S1A1, S1A2, S2A1), intermediate risk (S2A2, S1A3, S3A1, or high risk (S3A3, S3A2, S2A3).

RESULTS

Two hundred forty-six patients had intermediate Supp-SM grade AVMs. Of these patients, 102 had Supp-SM grade 5 (41.5%), 99 had Supp-SM grade 6 (40.2%), and 45 had Supp-SM grade 7 (18.3%). Significant differences in the proportions of patients with worse mRS scores at follow-up were found between the groups, with 24.5% (25/102) of patients in Supp-SM grade 5, 29.3% (29/99) in Supp-SM grade 6, and 57.8% (26/45) in Supp-SM grade 7 (p < 0.001). Patients with Supp-SM grade 7 AVMs had significantly increased odds of worse postoperative mRS scores (p < 0.001; OR 3.7, 95% CI 1.9-7.3). In the expanded cohort of 349 Supp-SM grade 6 AVM patients, a significantly higher proportion of older patients with larger Supp-SM grade 6 AVMs (grade 6+, 38.6%) had neurological deterioration than the others with Supp-SM grade 6 AVMs (22.9%, p = 0.02). Conversely, in an expanded cohort of 197 Supp-SM grade 7 AVM patients, a significantly lower proportion of younger patients with smaller Supp-SM grade 7 AVMs (grade 7-, 19%) had neurological deterioration than the others with Supp-SM grade 7 AVMs (44.9%, p = 0.01).

CONCLUSIONS

Patients with Supp-SM grade 7 AVMs are at increased risk of worse postoperative neurological outcomes, making Supp-SM grade 6 an appropriate operability cutoff. However, young patients with small niduses in the low-risk Supp-SM grade 7 group (grade 7-) have favorable postoperative outcomes. Outcomes in Supp-SM grade 7 patients did not improve with surgeon experience, indicating that the operability boundary is a hard limit reflecting the complexity of high-grade AVMs.

Microsurgery for Spetzler-Martin Grade I-III Arteriovenous Malformations: Analysis of Surgical Results and Correlation of Lawton-Young Supplementary Grade and Supplemented Spetzler-Martin Score with Functional Outcome

OBJECTIVE

To analyze the results of microsurgery for Spetzler-Martin (SM) grade I-III AVMs and evaluate the correlation of the Lawton-Young (LY) supplementary grade, supplemented Spetzler-Martin (SM-Supp/combined) score with the functional outcome.

METHODS

A total of 42 patients with SM grade I-III AVMs who had undergone surgery at our institute during a 3-year period (June 2013 to May 2016) were included in the present study.

RESULTS

All 42 patients had undergone primary surgery without previous embolization. Three patients (7.1%) had died due to surgical site hematoma in the postoperative period. One patient was lost to follow-up. The mean follow-up period for the remaining patients was 27 ± 14 months (range, 12-62 months). At the final follow-up examination of ≥12 months (FFU), 92.7% of the patients had a good outcome (modified Rankin scale [mRS] score ≤1), with an improved or unchanged mRS score in 87.8%. An AVM size >3 cm, diffuse AVM, SM grade III, and SM-Supp score >5 were associated with worsened mRS score at discharge and FFU. Higher LY grade (IV and V), eloquent AVM location, deep venous drainage, age >40 years, and unruptured presentation were not associated with worsened mRS score at both discharge and FFU. Of the 20 ARUBA-eligible patients, 19 (95%) had good outcomes. Postoperative angiograms for 39 patients revealed complete excision of the AVM in 37 (94.9%) and a residual AVM in 2 (5.1%).

CONCLUSIONS

High cure rates and excellent clinical outcomes can be expected with microsurgery for most patients with SM grade I-III AVMs. An AVM size >3 cm, diffuse AVM nidus, SM grade III, and SM-Supp score >5 are associated with postoperative worsening of functional scores in patients with SM grade I-III AVMs.

Effect of elevation of vascular endothelial growth factor level on exacerbation of hemorrhage in mouse brain arteriovenous malformation

OBJECTIVE

A high level of vascular endothelial growth factor (VEGF) has been implicated in brain arteriovenous malformation (bAVM) bleeding and rupture. However, direct evidence is missing. In this study the authors used a mouse bAVM model to test the hypothesis that elevation of focal VEGF levels in bAVMs exacerbates the severity of bAVM hemorrhage.

METHODS

Brain AVMs were induced in adult mice in which activin receptor-like kinase 1 (Alk1, a gene that causes AVM) gene exons 4-6 were floxed by intrabasal ganglia injection of an adenoviral vector expressing Cre recombinase to induce Alk1 mutation and an adeno-associated viral vector expressing human VEGF (AAV-VEGF) to induce angiogenesis. Two doses of AAV-VEGF (5 × 109 [high] or 2 × 109 [low]) viral genomes were used. In addition, the common carotid artery and external jugular vein were anastomosed in a group of mice treated with low-dose AAV-VEGF 6 weeks after the model induction to induce cerebral venous hypertension (VH), because VH increases the VEGF level in the brain. Brain samples were collected 8 weeks after the model induction. Hemorrhages in the bAVM lesions were quantified on brain sections stained with Prussian blue, which detects iron deposition. VEGF levels were quantified in bAVM tissue by enzyme-linked immunosorbent assay.

RESULTS

Compared to mice injected with a low dose of AAV-VEGF, the mice injected with a high dose had higher levels of VEGF (p = 0.003) and larger Prussian blue-positive areas in the bAVM lesion at 8 or 9 weeks after model induction (p = 0.002). VH increased bAVM hemorrhage in the low-dose AAV-VEGF group. The overall mortality in the high-dose AAV-VEGF group was 26.7%, whereas no mouse died in the low-dose AAV-VEGF group without VH. In contrast, VH caused a mortality of 50% in the low-dose AAV-VEGF group.

CONCLUSIONS

Using mouse bAVM models, the authors provided direct evidence that elevation of the VEGF level increases bAVM hemorrhage and mouse mortality.

Recent Advances in Basic Research for Brain Arteriovenous Malformation

Arteriovenous malformations (AVMs) are abnormal connections of vessels that shunt blood directly from arteries into veins. Rupture of brain AVMs (bAVMs) can cause life-threatening intracranial bleeding. Even though the majority of bAVM cases are sporadic without a family history, some cases are familial. Most of the familial cases of bAVMs are associated with a genetic disorder called hereditary hemorrhagic telangiectasia (HHT). The mechanism of bAVM formation is not fully understood. The most important advances in bAVM basic science research is the identification of somatic mutations of genes in RAS-MAPK pathways. However, the mechanisms by which mutations of these genes lead to AVM formation are largely unknown. In this review, we summarized the latest advance in bAVM studies and discussed some pathways that play important roles in bAVM pathogenesis. We also discussed the therapeutic implications of these pathways.

Quality of life and disability 12 months after surgery vs. conservative management for unruptured brain arteriovenous malformations: Scottish population-based and Australian hospital-based studies

BACKGROUND

Few data are available on disability and quality of life (QOL) after surgery versus conservative management for unruptured brain arteriovenous malformations (uAVMs).

OBJECTIVE

The aim of this study was to test the hypothesis that QOL and disability are worse after surgery ± preoperative embolisation for uAVM compared with conservative management.

METHODS

We included consecutive patients diagnosed with uAVM from a prospective population-based study in Scotland (1999-2003; 2006-2010) and a prospective hospital-based series in Australia (2011-2015). We assessed outcomes on the modified Rankin Scale (mRS) and the Short Form (SF)-36 at ~ 12 months after surgery or conservative treatment and compared these groups using continuous ordinal regression in the two cohorts separately.

RESULTS

Surgery was performed for 29% of all uAVM cases diagnosed in Scotland and 84% of all uAVM referred in Australia. There was no statistically significant difference between surgery and conservative management at 12 months among 79 patients in Scotland (mean SF-36 Physical Component Score (PCS) 39 [SD 14] vs. 39 [SD 13]; mean SF-36 Mental Component Score (MCS) 38 [SD 14] vs. 39 [SD 14]; mRS > 1, 24 vs. 9%), nor among 37 patients in Australia (PCS 51 [SD 10] vs. 49 [SD 6]; MCS 48 [SD 12] vs. 49 [SD 10]; mRS > 1, 19 vs. 30%). In the Australian series, there was no statistically significant change in the MCS and PCS between baseline before surgery or conservative management and 12 months.

CONCLUSIONS

We did not find a statistically significant difference between surgery ± preoperative embolisation and conservative management in disability or QOL at 12 months.

A proposed classification for assessing rupture risk in patients with intracranial arteriovenous malformations

Background:

Whether cerebral arteriovenous malformations (AVMs) should be treated remains an ongoing debate. Nevertheless, there is a need for predictive factors that assist in labelling lesions as low or high risk for future rupture. Our aim was to design a new classification that would consider hemodynamic and anatomic factors in the rapid assessment of rupture risk in patients with AVMs.

Methods:

This was a retrospective study that included 639 patients with ruptured and unruptured AVMs. We proposed a new classification score (1–4 points) for AVM rupture risk using three factors: feeding artery mean velocity (Vm), nidus size, and type of venous drainage. We employed descriptive statistics and logistic regression analysis.

Results:

A total of 639 patients with cerebral AVMs, 388 (60%) had unruptured AVMs and 251 (40%) had ruptured AVMs. Logistic regression analysis revealed a significant effect of Vm, nidus size, and venous drainage type in accounting for the variability of rupture odds (P = 0.0001, R² = 0.437) for patients with AVMs. Based in the odds ratios, grades 1 and 2 of the proposed classification were corresponded to low risk of hemorrhage, while grades 3 and 4 were associated with hemorrhage: 1 point OR = (0.107 95% CI; 0.061–0.188), 2 point OR = (0.227 95% CI; 0.153–0.338), 3 point OR = (3.292 95% CI; 2.325–4.661), and 4 point OR = (23.304 95% CI; 11.077–49.027).

Conclusion:

This classification is useful and easy to use, and it may allow for the individualisation of each cerebral AVM and the assessment of rupture risk based on a model of categorisation.

Responses to ARUBA: a systematic review and critical analysis for the design of future arteriovenous malformation trials

OBJECTIVE The ARUBA study (A Randomized Trial of Unruptured Brain Arteriovenous Malformations [AVMs]) on unruptured brain AVMs has been the object of comments and editorials. In the present study the authors aim to systematically review critiques, discuss design issues, and propose a framework for future trials. METHODS The authors performed a systematic review of the French and English literature on the ARUBA study published between January 2006 and February 2015. The electronic search, including the Cochrane Library, MEDLINE (PubMed and Ovid), CINAHL, and EMBASE databases, was complemented by hand searching and cross-referencing. The comments were categorized as items related to the design, the conduct, and the analysis and interpretation of the trial. RESULTS Thirty-one articles or letters were identified. The pragmatic design, with heterogeneity of patients and lack of standardization of the treatment arm, were frequently stated concerns. The choice of outcome measures was repeatedly criticized. During the trial, low enrollment rates, selection bias, and premature interruption of enrollment were frequent comments. The short follow-up period, the lack of subgroup analyses, the lack of details on the results of the various treatments, and a contentious interpretation of results were noted at the analysis stage. A fundamental problem was the primary hypothesis testing conservative management. The authors believe that other trials are needed. Future trials could be pragmatic, test interventions stratified at the time of randomization, and look for long-term, hard clinical outcomes in a large number of patients. CONCLUSIONS In the authors' view, the ARUBA trial is a turning point in the history of brain AVM management; future trials should aim at integrating trial methodology and clinical care in the presence of uncertainty.

Management of unbled brain arteriovenous malformation study

In a recent trial limited to arteriovenous malformations discovered not to have bled, medical management was superior to medical management plus intervention. The trial was halted after 226 randomizations and a mean follow-up of 3.3 years owing to a disparity favoring the medical arm. Eligible patients were selected as suitable for lesion eradication. The initial sample size of 800 and follow-up plans for a mean of 7 years were lowered and shortened, respectively, by the outcome data. An application for extended follow-up was given poor priority scores owing to estimations that the disparities in outcomes would not change significantly.

Vascular Integrity in the Pathogenesis of Brain Arteriovenous Malformation

Brain arteriovenous malformation (bAVM) is an important cause of intracranial hemorrhage (ICH), particularly in the young population. ICH is the first clinical symptom in about 50 % of bAVM patients. The vessels in bAVM are fragile and prone to rupture, causing bleeding into the brain. About 30 % of unruptured and non-hemorrhagic bAVMs demonstrate microscopic evidence of hemosiderin in the vascular wall. In bAVM mouse models, vascular mural cell coverage is reduced in the AVM lesion, accompanied by vascular leakage and microhemorrhage. In this review, we discuss possible signaling pathways involved in abnormal vascular development in bAVM.

Animal Models in Studying Cerebral Arteriovenous Malformation

Brain arteriovenous malformation (AVM) is an important cause of hemorrhagic stroke. The etiology is largely unknown and the therapeutics are controversial. A review of AVM-associated animal models may be helpful in order to understand the up-to-date knowledge and promote further research about the disease. We searched PubMed till December 31, 2014, with the term “arteriovenous malformation,” limiting results to animals and English language. Publications that described creations of AVM animal models or investigated AVM-related mechanisms and treatments using these models were reviewed. More than 100 articles fulfilling our inclusion criteria were identified, and from them eight different types of the original models were summarized. The backgrounds and procedures of these models, their applications, and research findings were demonstrated. Animal models are useful in studying the pathogenesis of AVM formation, growth, and rupture, as well as in developing and testing new treatments. Creations of preferable models are expected.

Safety of neuroangiography and embolization in children: complication analysis of 697 consecutive procedures in 394 patients

OBJECT

The safe treatment of children using catheter-based angiography and embolization poses unique challenges because of the technical factors regarding the size and fragility of access and target vessels, as well as unique pediatric cerebrovascular pathologies. The complication rates for neurointerventional procedures in children have not been established.

METHODS

The records of a consecutive cohort of pediatric patients who underwent neuroangiography and/or embolization between 2007 and 2013 were reviewed retrospectively to identify both intraprocedural and postprocedural complications. Demographic and clinical risk factors were analyzed with a multivariate logistic regression model.

RESULTS

The 697 consecutive procedures consisted of 429 diagnostic angiograms and 268 embolizations (mean age of patients 11.1 years; range 4 days to 18 years; 217 females). There were 130 intracranial, 122 extracranial, and 16 spinal embolizations. Pathologies included 28 intracranial arteriovenous malformations (AVMs), 12 spinal AVMs, 19 aneurysms, 29 vein of Galen malformations, 29 dural arteriovenous fistulas, 96 extracranial AVMs, 39 tumors, 3 strokes, and 13 others. Overall, 2 intraprocedural and 1 postprocedural complication (0.7%) occurred in the diagnostic group, all of which were nonneurological events. In the embolization group, 7 intraprocedural and 11 postprocedural complications (6.7%) were observed. Of these complications, 15 were nonneurological events (5.6%), 1 was a short-term neurological event (0.4%), and 2 were long-term neurological events (0.7%).

CONCLUSIONS

Neither the technical challenges posed by children's access and target vessels nor the unique neuro-vascular pathologies seen in children need result in an elevated morbidity rate related to neuroangiography and embolization. At a dedicated high-volume center, the complication rates may be lower than those for comparable procedures performed in adults.

Partial thrombosed parasagittal AVM, complete resection. Case report

INTRODUCTION: Arteriovenous malformations (AVMs) are congenital lesions formed by a network of dysplastic vessels.

CASE REPORT: We report a case of a 63 years old man, admitted with seizures and headache. Imaging findings, angio-CT, angio-MR and angiography revealed a partially thombosed right parasagittal frontal AVM, with fully thrombosed associated flow-related aneurysm on the main arterial feeder. The patient underwent surgery and we performed total resection of the AVM. The particularity of this case is the rare possibility of outcome with regression of the vascular malformation.

CONCLUSIONS: Brain AVMs are evolutive lesions. Regression, through progressive thrombosis of the nidus is a rare possible outcome in brain AVMs. In thrombosed AVMs angiography is not reliable, and angio-CT and/or angio-MR are mandatory, in order to correctly evaluate nidus size and associated lesions. Symptomatic AVMs require surgery. Partial thombosed AVMs can be safely resected.

Current surgical results with low-grade brain arteriovenous malformations

OBJECT

Resection is an appealing therapy for brain arteriovenous malformations (AVMs) because of its high cure rate, low complication rate, and immediacy, and has become the first-line therapy for many AVMs. To clarify safety, efficacy, and outcomes associated with AVM resection in the aftermath of A Randomized Trial of Unruptured Brain AVMs (ARUBA), the authors reviewed their experience with low-grade AVMs-the most favorable AVMs for surgery and the ones most likely to have been selected for treatment outside of ARUBA's randomization process.

METHODS

A prospective AVM registry was searched to identify patients with Spetzler-Martin Grade I and II AVMs treated using resection during a 16-year period.

RESULTS

Of the 232 surgical patients included, 120 (52%) presented with hemorrhage, 33% had Spetzler-Martin Grade I, and 67% had Grade II AVMs. Overall, 99 patients (43%) underwent preoperative embolization, with unruptured AVMs embolized more often than ruptured AVMs. AVM resection was accomplished in all patients and confirmed angiographically in 218 patients (94%). There were no deaths among patients with unruptured AVMs. Good outcomes (modified Rankin Scale [mRS] score 0-1) were found in 78% of patients, with 97% improved or unchanged from their preoperative mRS scores. Patients with unruptured AVMs had better functional outcomes (91% good outcome vs 65% in the ruptured group, p = 0.0008), while relative outcomes were equivalent (98% improved/unchanged in patients with ruptured AVMs vs 96% in patients with unruptured AVMs).

CONCLUSIONS

Surgery should be regarded as the "gold standard" therapy for the majority of low-grade AVMs, utilizing conservative embolization as a preoperative adjunct. High surgical cure rates and excellent functional outcomes in patients with both ruptured and unruptured AVMs support a dominant surgical posture for low-grade AVMS, with radiosurgery reserved for risky AVMs in deep, inaccessible, and highly eloquent locations. Despite the technological advances in endovascular and radiosurgical therapy, surgery still offers the best cure rate, lowest risk profile, and greatest protection against hemorrhage for low-grade AVMs. ARUBA results are influenced by a low randomization rate, bias toward nonsurgical therapies, a shortage of surgical expertise, a lower rate of complete AVM obliteration, a higher rate of delayed hemorrhage, and short study duration. Another randomized trial is needed to reestablish the role of surgery in unruptured AVM management.

Radiosurgery for ruptured intracranial arteriovenous malformations

Object

Ruptured intracranial arteriovenous malformations (AVMs) are at a significantly greater risk for future hemorrhage than unruptured lesions, thereby necessitating treatment in the majority of cases. In a retrospective, single-center study, the authors describe the outcomes after radiosurgery in a large cohort of patients with ruptured AVMs.

Methods

From an institutional review board–approved, prospectively collected AVM radiosurgery database, the authors identified all patients with a history of AVM rupture. They analyzed obliteration rates in all patients in whom radiological follow-up data were available (n = 639). However, to account for the latency period associated with radiosurgery, only those patients with more than 2 years of radiological follow-up and those with earlier AMV obliteration were included in the analysis of prognostic factors related to obliteration and complications. This resulted in a cohort of 565 patients with ruptured AVMs for whom data were analyzed; these patients had a median radiological follow-up of 57 months and a median age of 29 years. Twenty-one percent of the patients underwent preradiosurgery embolization. The median volume and prescription dose were 2.1 cm3 and 22 Gy, respectively. The Spetzler-Martin grade was III or higher in 56% of patients, the median radiosurgery-based AVM score was 1.08, and the Virginia Radiosurgery AVM Scale (RAS) score was 3 to 4 points in 44%. Survival and regression analyses were performed to determine obliteration rates over time and predictors of obliteration and complications.

Results

In the overall population of 639 patients with ruptured AVMs, the obliteration rate was 11.1% based on MRI only (71 of 639 patients), 56.0% based on angiography (358 of 639), and 67.1% based on combined modalities (429 of 639 patients). In the cohort of patients with 2 years of follow-up or an earlier AVM obliteration, the cumulative obliteration rate was 76% and the actuarial obliteration rates were 41% and 64% at 3 and 5 years, respectively. Multivariate analysis identified the absence of preradiosurgery embolization (p < 0.001), increased prescription dose (p = 0.001), the presence of a single draining vein (p = 0.046), no postradiosurgery-related hemorrhage (p = 0.007), and lower Virginia RAS score (p = 0.020) as independent predictors of obliteration. The annual risk of a hemorrhage occurring during the latency period was 2.0% and the rate of hemorrhage-related morbidity and mortality was 1.6%. Multivariate analysis showed that decreased prescription dose (p < 0.001) and multiple draining veins (p = 0.003) were independent predictors of postradiosurgery hemorrhage. The rates of symptomatic and permanent radiation-induced changes were 8% and 2.7%, respectively. In the multivariate analysis, a single draining vein (p < 0.001) and higher Virginia RAS score (p = 0.005) were independent predictors of radiation-induced changes following radiosurgery.

Conclusions

Radiosurgery effectively treats ruptured AVMs with an acceptably low risk-to-benefit ratio. For patients with ruptured AVMs, favorable outcomes are more likely when preradiosurgical embolization is avoided and a higher prescription dose can be delivered.

Radiosurgery for primary motor and sensory cortex arteriovenous malformations: outcomes and the effect of eloquent location

BACKGROUND

Eloquent intracranial arteriovenous malformations (AVMs) located in the primary motor or somatosensory cortex (PMSC) carry a high risk of microsurgical morbidity.

OBJECTIVE

To evaluate the outcomes of radiosurgery on PMSC AVMs and compare them with radiosurgery outcomes in a matched cohort of noneloquent lobar AVMs.

METHODS

Between 1989 and 2009, 134 patients with PMSC AVMs underwent Gamma Knife radiosurgery with a median radiographic and clinical follow-up of 64 and 80 months, respectively. Seizure (40.3%) and hemorrhage (28.4%) were the most common presenting symptoms. Pre-radiosurgery embolization was performed in 33.6% of AVMs. Median AVM volume was 4.1 mL (range, 0.1-22.6 mL), and prescription dose was 20 Gy (range, 7-30 Gy). Cox regression analysis was performed to identify factors associated with obliteration.

RESULTS

The overall obliteration rate, including magnetic resonance imaging and angiography, after radiosurgery was 63%. Obliteration was achieved in 80% of AVMs with a volume less than 3 mL compared with 55% for AVMs larger than 3 mL. No previous embolization (P = .002) and a single draining vein (P = .001) were independent predictors of obliteration on multivariate analysis. The annual post-radiosurgery hemorrhage risk was 2.5%. Radiosurgery-related morbidity was temporary and permanent in 14% and 6% of patients, respectively. Comparing PMSC AVMs with matched noneloquent lobar AVMs, the obliteration rates and clinical outcomes after radiosurgery were not statistically different.

CONCLUSION

For patients harboring PMSC AVMs, radiosurgery offers a reasonable chance of obliteration with a relatively low complication rate. Eloquent location does not appear to confer the same negative prognostic value for radiosurgery that it does for microsurgery.

Temporal lobe arteriovenous malformations: surgical outcomes with a focus on visual field defects and epilepsy

BACKGROUND

Temporal lobe arteriovenous malformations (AVMs) represent a subgroup of intracranial AVMs with particular characteristics and management issues.

OBJECTIVE

To characterize the surgical outcomes of temporal lobe AVMs with emphasis on visual field deficits (VFDs) and seizures.

METHODS

Between 1992 and 2008, 29 patients were operated on for temporal lobe AVMs. Patient data were retrospectively collected and analyzed.

RESULTS

Twelve of 29 patients (41.4%) presented with seizures and 4 (13.7%) presented with VFDs. Postoperatively, 6 patients (24%) showed new VFDs and 2 improved, with a rate of preservation of full visual fields of 84%. Larger AVMs (> 3 cm) were significantly associated with postoperative VFD (P = .008). Epilepsy outcomes assessed by the Engel scale were as follows: 9 patients (75%) were in class I (seizure free), 1 patient (8.3%) was in class III, and 2 patients (16.6%) were in class IV (no change or worsening). Postoperative modified Rankin Scale outcomes were excellent (grade 0-1) in 18 patients, good (grade 2) in 7, and poor (grade 3-4) in 4. Older age at diagnosis correlated with a worse functional outcome (Spearman ρ = 0.369; P = .049). AVMs were totally removed in 27 of 29 patients (93.1%). Complete surgical excision was confirmed with angiography. Two patients needed reoperation for AVM remnant. Three patients had persistent hemiparesis (10.3% permanent morbidity). There was no mortality.

CONCLUSION

Seizure control is usually underappreciated in the surgical management of AVMs. However, in temporal lobe AVMs, good outcomes with low morbidity and good visual field preservation can be accomplished.

Radiosurgery for low-grade intracranial arteriovenous malformations

OBJECT

Low-grade, or Spetzler-Martin (SM) Grades I and II, arteriovenous malformations (AVMs) are associated with lower surgical morbidity rates than higher-grade lesions. While radiosurgery is now widely accepted as an effective treatment approach for AVMs, the risks and benefits of the procedure for low-grade AVMs, as compared with microsurgery, remain poorly understood. The authors of this study present the outcomes for a large cohort of low-grade AVMs treated with radiosurgery.

METHODS

From an institutional radiosurgery database comprising approximately 1450 AVM cases, all patients with SM Grade I and II lesions were identified. Patients with less than 2 years of radiological follow-up, except those with complete AVM obliteration, were excluded from analysis. Univariate and multivariate Cox proportional-hazards and logistic regression analyses were used to determine factors associated with obliteration, radiation-induced changes (RICs), and hemorrhage following radiosurgery.

RESULTS

Five hundred two patients harboring low-grade AVMs were eligible for analysis. The median age was 35 years, 50% of patients were male, and the most common presentation was hemorrhage (47%). The median AVM volume and prescription dose were 2.4 cm(3) and 23 Gy, respectively. The median radiological and clinical follow-up intervals were 48 and 62 months, respectively. The cumulative obliteration rate was 76%. The median time to obliteration was 40 months, and the actuarial obliteration rates were 66% and 80% at 5 and 10 years, respectively. Independent predictors of obliteration were no preradiosurgery embolization (p < 0.001), decreased AVM volume (p = 0.005), single draining vein (p = 0.013), lower radiosurgery-based AVM scale score (p = 0.016), and lower Virginia Radiosurgery AVM Scale (Virginia RAS) score (p = 0.001). The annual postradiosurgery hemorrhage rate was 1.4% with increased AVM volume (p = 0.034) and lower prescription dose (p = 0.006) as independent predictors. Symptomatic and permanent RICs were observed in 8.2% and 1.4% of patients, respectively. No preradiosurgery hemorrhage (p = 0.011), a decreased prescription dose (p = 0.038), and a higher Virginia RAS score (p = 0.001) were independently associated with postradiosurgery RICs.

CONCLUSIONS

Spetzler-Martin Grade I and II AVMs are very amenable to successful treatment with stereotactic radiosurgery. While patient, physician, and institutional preferences frequently dictate the final course of treatment, radiosurgery offers a favorable risk-to-benefit profile for the management of low-grade AVMs.

Medical management with or without interventional therapy for unruptured brain arteriovenous malformations (ARUBA): a multicentre, non-blinded, randomised trial

BACKGROUND

The clinical benefit of preventive eradication of unruptured brain arteriovenous malformations remains uncertain. A Randomised trial of Unruptured Brain Arteriovenous malformations (ARUBA) aims to compare the risk of death and symptomatic stroke in patients with an unruptured brain arteriovenous malformation who are allocated to either medical management alone or medical management with interventional therapy.

METHODS

Adult patients (≥18 years) with an unruptured brain arteriovenous malformation were enrolled into this trial at 39 clinical sites in nine countries. Patients were randomised (by web-based system, in a 1:1 ratio, with random permuted block design [block size 2, 4, or 6], stratified by clinical site) to medical management with interventional therapy (ie, neurosurgery, embolisation, or stereotactic radiotherapy, alone or in combination) or medical management alone (ie, pharmacological therapy for neurological symptoms as needed). Patients, clinicians, and investigators are aware of treatment assignment. The primary outcome is time to the composite endpoint of death or symptomatic stroke; the primary analysis is by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00389181.

FINDINGS

Randomisation was started on April 4, 2007, and was stopped on April 15, 2013, when a data and safety monitoring board appointed by the National Institute of Neurological Disorders and Stroke of the National Institutes of Health recommended halting randomisation because of superiority of the medical management group (log-rank Z statistic of 4·10, exceeding the prespecified stopping boundary value of 2·87). At this point, outcome data were available for 223 patients (mean follow-up 33·3 months [SD 19·7]), 114 assigned to interventional therapy and 109 to medical management. The primary endpoint had been reached by 11 (10·1%) patients in the medical management group compared with 35 (30·7%) in the interventional therapy group. The risk of death or stroke was significantly lower in the medical management group than in the interventional therapy group (hazard ratio 0·27, 95% CI 0·14-0·54). No harms were identified, other than a higher number of strokes (45 vs 12, p<0·0001) and neurological deficits unrelated to stroke (14 vs 1, p=0·0008) in patients allocated to interventional therapy compared with medical management.

INTERPRETATION

The ARUBA trial showed that medical management alone is superior to medical management with interventional therapy for the prevention of death or stroke in patients with unruptured brain arteriovenous malformations followed up for 33 months. The trial is continuing its observational phase to establish whether the disparities will persist over an additional 5 years of follow-up.

FUNDING

National Institutes of Health, National Institute of Neurological Disorders and Stroke.

Advances in Radiosurgery for Arteriovenous Malformations of the Brain

Arteriovenous malformations of the brain are a considerable source of morbidity and mortality for patients who harbor them. Although our understanding of this disease has improved, it remains in evolution. Advances in our ability to treat these malformations and the modes by which we address them have also improved substantially. However, the variety of patient clinical and disease scenarios often leads us into challenging and complex management algorithms as we balance the risks of treatment against the natural history of the disease. The goal of this article is to provide a focused review of the natural history of cerebral arteriovenous malformations, to examine the role of stereotactic radiosurgery, to discuss the role of endovascular therapy as it relates to stereotactic radiosurgery, and to look toward future advances.

Radiosurgery for Spetzler-Martin Grade III arteriovenous malformations

OBJECT

Intracranial arteriovenous malformations (AVMs) are most commonly classified based on their Spetzler-Martin grades. Due to the composition of the Spetzler-Martin grading scale, Grade III AVMs are the most heterogeneous, comprising 4 distinct lesion subtypes. The management of this class of AVMs and the optimal treatment approach when intervention is indicated remain controversial. The authors report their experience with radiosurgery for the treatment of Grade III AVMs in a large cohort of patients.

METHODS

All patients with Spetzler-Martin Grade III AVMs treated with radiosurgery at the University of Virginia over the 20-year span from 1989 to 2009 were identified. Patients who had less than 2 years of radiological follow-up and did not have evidence of complete obliteration during that period were excluded from the study, leaving 398 cases for analysis. The median patient age at treatment was 31 years. The most common presenting symptoms were hemorrhage (59%), seizure (20%), and headache (10%). The median AVM volume was 2.8 cm(3), and the median prescription dose was 20 Gy. The median radiological and clinical follow-up intervals were 54 and 68 months, respectively. Univariate and multivariate Cox proportional hazards and logistic regression analysis were used to identify factors associated with obliteration, postradiosurgery radiation-induced changes (RIC), and favorable outcome.

RESULTS

Complete AVM obliteration was observed in 69% of Grade III AVM cases at a median time of 46 months after radiosurgery. The actuarial obliteration rates at 3 and 5 years were 38% and 60%, respectively. The obliteration rate was higher in ruptured AVMs than in unruptured ones (p < 0.001). Additionally, the obliteration rate for Grade III AVMs with small size (< 3 cm diameter), deep venous drainage, and location in eloquent cortex was higher than for the other subtypes (p < 0.001). Preradiosurgery AVM rupture (p = 0.016), no preradiosurgery embolization (p = 0.003), increased prescription dose (p < 0.001), fewer isocenters (p = 0.006), and a single draining vein (p = 0.018) were independent predictors of obliteration. The annual risk of postradiosurgery hemorrhage during the latency period was 1.7%. Two patients (0.5%) died of hemorrhage during the radiosurgical latency period. The rates of symptomatic and permanent RIC were 12% and 4%, respectively. Absence of preradiosurgery AVM rupture (p < 0.001) and presence of a single draining vein (p < 0.001) were independent predictors of RIC. Favorable outcome was observed in 63% of patients. Independent predictors of favorable outcome were no preradiosurgery hemorrhage (p = 0.014), increased prescription dose (p < 0.001), fewer isocenters (p = 0.014), deep location (p = 0.014), single draining vein (p = 0.001), and lower Virginia radiosurgery AVM scale score (p = 0.016).

CONCLUSIONS

Radiosurgery for Spetzler-Martin Grade III AVMs yields relatively high rates of obliteration with a low rate of adverse procedural events. Small and ruptured lesions are more likely to become obliterated after radiosurgery than large and unruptured ones.

Outcomes following single-session radiosurgery for high-grade intracranial arteriovenous malformations

INTRODUCTION

The management of Spetzler-Martin Grade-IV and -V arteriovenous malformations (AVMs) is controversial due to their uncertain natural history, the high rate of morbidity and mortality associated with microsurgical resection, and the relatively low rate of successful obliteration from less invasive approaches such as radiosurgery and embolization. We present our radiosurgical results for high-grade AVMs.

METHODS

We identified all patients with Spetzler-Martin Grade-IV and -V AVMs treated with single-session radiosurgery at the University of Virginia between 1989 and 2009. Patients with less than 2 years of follow-up without obliteration were excluded. This yielded 110 patients with a median age 27.6 years. The median AVM volume was 5.7 cc and prescription dose was 19 Gy. The median radiographic and clinical follow-up intervals were 88 and 97 months, respectively.

RESULTS

Complete AVM obliteration was identified on MRI only in 11 patients (10%) and confirmed by DSA in 38 patients (34%) for a cumulative obliteration rate of 44%. The actuarial rates of obliteration at 3 and 5 years were 10% and 23%, respectively. The mean and median times to obliteration were 60 months and 43 months, respectively. Significant independent predictors of obliteration were no pre-radiosurgery embolization (P = 0.008), superficial location (P = 0.001), and higher prescription dose (P = 0.028). The annual rate of post-radiosurgery hemorrhage was 3.0%, and symptomatic RIC was observed in 12% of patients. Unruptured AVMs were more likely to have RIC (P = 0.005). The rates of temporary and permanent post-radiosurgery clinical deterioration were 9% and 10%, respectively.

CONCLUSION

Single-session radiosurgery is an acceptable treatment option for select patients harboring high-grade AVMs for which microsurgery or conservative management are associated with an unacceptably high risk of adverse outcomes.

Radiosurgery for patients with unruptured intracranial arteriovenous malformations

Object

The appropriate management of unruptured intracranial arteriovenous malformations (AVMs) remains controversial. In the present study, the authors evaluate the radiographic and clinical outcomes of radiosurgery for a large cohort of patients with unruptured AVMs.

Methods

From a prospective database of 1204 cases of AVMs involving patients treated with radiosurgery at their institution, the authors identified 444 patients without evidence of rupture prior to radiosurgery. The patients' mean age was 36.9 years, and 50% were male. The mean AVM nidus volume was 4.2 cm3, 13.5% of the AVMs were in a deep location, and 44.4% were at least Spetzler-Martin Grade III. The median radiosurgical prescription dose was 20 Gy. Univariate and multivariate Cox regression analyses were used to determine risk factors associated with obliteration, postradiosurgery hemorrhage, radiation-induced changes, and postradiosurgery cyst formation. The mean duration of radiological and clinical follow-up was 76 months and 86 months, respectively.

Results

The cumulative AVM obliteration rate was 62%, and the postradiosurgery annual hemorrhage rate was 1.6%. Radiation-induced changes were symptomatic in 13.7% and permanent in 2.0% of patients. The statistically significant independent positive predictors of obliteration were no preradiosurgery embolization (p < 0.001), increased prescription dose (p < 0.001), single draining vein (p < 0.001), radiological presence of radiation-induced changes (p = 0.004), and lower Spetzler-Martin grade (p = 0.016). Increased volume and higher Pittsburgh radiosurgery-based AVM score were predictors of postradiosurgery hemorrhage in the univariate analysis only. Clinical deterioration occurred in 30 patients (6.8%), more commonly in patients with postradiosurgery hemorrhage (p = 0.018).

Conclusions

Radiosurgery afforded a reasonable chance of obliteration of unruptured AVMs with relatively low rates of clinical and radiological complications.

The diagnosis and management of brain arteriovenous malformations

Although uncommon in the general population, cerebral arteriovenous malformations (AVMs) can pose a significant health risk if a rupture occurs. Advances in noninvasive imaging have led to an increase in the identification of unruptured AVMs, presenting new challenges in management, given their poorly understood natural history. Over the past decade, there have been significant developments in the management and treatment of intracranial AVMs. This article discusses the pathophysiology, natural history, clinical presentations, and current treatment options, including multimodal approaches, for these vascular malformations.

Etiologies of intracerebral hematomas

Intracerebral hemorrhage (ICH) remains a life-threatening disease that carries significant morbidity and mortality despite recent diagnostic and management advances. Various conditions are associated with increased risk of intracerebral hemorrhage. Understanding the etiology of these conditions and their pathophysiological contribution to ICH will likely lead to better therapeutic and preventative measures and improve the morbidity and mortality associated with intracerebral hemorrhage. We will review the current literature regarding important etiologies/risk factors of intracerebral hemorrhage.

Management of ruptured brain arteriovenous malformations

Intracranial arteriovenous malformations (AVMs) are a common cause of stroke in younger patients, and often present as intracerebral hemorrhages (ICH), associated with 10 % to 30 % mortality. Patients who present with a hemorrhage from an AVM should be initially stabilized according to acute management guidelines for ICH. The characteristics of a lesion including its size, location in eloquent tissue, and high-risk features will influence risk of rupture, prognosis, as well as help guide management decisions. Given that rupture is associated with an increased risk of 6 % re-rupture in the year following the initial hemorrhage, versus 1 % to 3 % predicted annual risk in non-ruptured lesions only, definitive treatment is encouraged after ICH stabilization. A rest period of 2 to 6 weeks after hemorrhage is recommended before definitive treatment to avoid disrupting friable parenchyma and the hematoma. Treatment may consist of endovascular embolization, surgical resection, radiosurgery, or a combination of these three interventions based on the lesion.

The outlook for adults with epileptic seizure(s) associated with cerebral cavernous malformations or arteriovenous malformations

Cerebral cavernous malformations (CCMs) and arteriovenous malformations (AVMs) are common: their asymptomatic prevalence on brain magnetic resonance imaging (MRI) is 1 in 625 and 1 in 2,000, respectively. The risk of epileptic seizure(s) for people with AVMs and CCMs affects their domestic, social, and professional lives, and may influence their decisions about treatment. This article summarizes the seizure risks for people with AVMs and CCMs, gleaned from published original articles indexed in OVID Medline and Embase before 1 January 2012. In the absence of prior intracranial hemorrhage and nonhemorrhagic focal neurologic deficit, a population-based study in Scotland, United Kingdom, found that the 5-year risks of first seizure were 8% for AVM and 4% for CCM; presentation with intracranial hemorrhage or focal neurologic deficit raised this risk for AVM (23%) but not for CCM (6%). Features associated with the occurrence of epileptic seizures for CCM are lesion multiplicity and cortical CCM location, whereas for AVM the most consistently reported associations are younger age, temporal location, cortical involvement, and nidus diameter >3 cm. In the absence of prior intracranial hemorrhage and nonhemorrhagic focal neurologic deficit, the 5-year risk of developing epilepsy following a first seizure is 58% for AVM and 94% for CCM, though there is no difference in the chance of achieving 2-year seizure freedom in this time frame (45% AVM vs. 47% CCM). Observational case series describe encouraging differences in seizure frequency before and after AVM and CCM treatment, but the shortage of studies demonstrating dramatic effects in comparison to concurrent control groups justifies the need for more controlled studies, ideally with randomized treatment allocation when the benefits of AVM or CCM treatment are uncertain.

Embolization and radiosurgery for arteriovenous malformations

The treatment of arteriovenous malformations (AVMs) requires a multidisciplinary management including microsurgery, endovascular embolization, and stereotactic radiosurgery (SRS). This article reviews the recent advancements in the multimodality treatment of patients with AVMs using endovascular neurosurgery and SRS. We describe the natural history of AVMs and the role of endovascular and radiosurgical treatment as well as their interplay in the management of these complex vascular lesions. Also, we present some representative cases treated at our institution.

Hemodynamic changes in patients with arteriovenous malformations assessed using high-resolution 3D radial phase-contrast MR angiography

BACKGROUND AND PURPOSE

Arteriovenous malformations have a high lifetime risk of hemorrhage; however, treatment carries a significant risk of morbidity and mortality, including permanent neurologic sequelae. WSS and other hemodynamic parameters are altered in patients with symptomatic AVMs, and analysis of hemodynamics may have value in stratifying patients into different risk groups. In this study, we examined hemodynamic data from patients with stable symptoms and those who presented with acute symptoms to identify trends which may help in risk stratification.

MATERIALS AND METHODS

Phase-contrast MRA using a radial readout (PC-VIPR) is a fast, high-resolution technique that can acquire whole-brain velocity-encoded angiograms with scan times of approximately 5 minutes. Ten patients with AVMs were scanned using PC-VIPR; velocity, area, flow, and WSS in vessels feeding the AVMs and normal contralateral vessels were calculated using velocity data from the phase-contrast acquisition.

RESULTS

Patients with an asymptomatic presentation or mild symptoms (n = 4) had no significant difference in WSS in feeding vessels compared with normal contralateral vessels, whereas patients presenting with hemorrhage, severe headaches/seizures, or focal neurologic deficits (n = 6) had significantly higher WSS in feeding vessels compared with contralateral vessels.

CONCLUSIONS

In this study, we demonstrate that estimates of WSS and other hemodynamic parameters can be obtained noninvasively in patients with AVMs in clinically useful imaging times. Variation in WSS between feeders and normal vessels appears to relate to the clinical presentation of the patient. Further analysis of hemodynamic changes may improve characterization and staging of AVM patients, when combined with existing risk factors.

Trends in the management of intracranial vascular malformations in the USA from 2000 to 2007

Objective. To assess prevalence, clinical characteristics, trends in treatment pattern, and outcome in patients with intracranial vascular malformations (IVMs). Methods. Nationwide inpatient sample. Patients with the diagnosis of an IVM admitted to US hospitals from 2000 to 2007. Results. In 58,051 IVM-related admissions (detection rate 2.4/100,000 person-years; mean age 49 ± 17 years; 52% women) major diagnoses were intracranial hemorrhage (ICrH) in 15%, seizure 32%, ischemia 5%, and headache 9%. Procedures included surgery (13%), embolization (13%), radiation therapy (2%), aneurysm clipping (1%), and mechanical ventilation (6%). Ventilation and ICrH were associated with death (2%), whereas ventilation, ICrH, surgery, seizure, and ischemia were associated with unfavorable outcome (20%). IVM detection rate and hospital outcome remained stable over time, whereas mean age and comorbid diagnosis of cerebral ischemia increased (ICrH and seizure decreased). Conclusion. IVMs are infrequent and present in 1/6 patients with some form of ICrH. Overall, seizure is the dominant comorbid diagnosis (1/3 patients). IVMs are equally prevalent among race-ethnic groups and are increasingly detected later in life. The inpatient care of IVM patients results in death or discharge into specialized care in 1/5 patients.