Brain arteriovenous malformations and endovascular treatment: effect on seizures

When the Music Comes From the Brain: A Rare Case of Auditory Seizures Secondary to a Right Temporal Lobe Arteriovenous Malformation

Focal seizures with subjective auditory phenomena, known as auditory seizures, are uncommon and can include simple to complex auditory hallucinations. We present a case of a 59-year-old man who presented with motor and non-motor seizures. He had a four-month history of hearing things resembling continuous metallic sounds, pennies dropping into a bank, persistent music after radio cessation, and the sound of a passing train. Brain MRI showed multiple serpiginous flow voids in the right temporal lobes, consistent with an arteriovenous malformation that was confirmed eventually with a diagnostic brain angiogram. The etiology of the seizures was related to a structural lesion in the setting of a right temporal arteriovenous malformation (AVM). Treatment with 2000mg of levetiracetam twice daily and 300mg of oxcarbazepine twice daily improved symptoms, and subsequent stereotactic radiosurgery ablation successfully treated the AVM. Post-treatment MRI showed reduced visibility of parasitized vessels, with controlled generalized seizures but partial control of auditory seizures.

Seizure Outcomes After Interventional Treatment in Cerebral Arteriovenous Malformation-Associated Epilepsy: A Systematic Review and Meta-Analysis

BACKGROUND

Seizures are the second most common presenting symptom of cerebral arteriovenous malformations (AVMs). Evidence supporting different treatment modalities is continuously evolving and it remains unclear which modality offers better seizure outcomes.

OBJECTIVE

To compare various interventional treatment modalities (i.e., microsurgery, radiosurgery, endovascular embolization, or multimodality treatment), regarding outcomes in AVM-associated epilepsy.

METHODS

PubMed, Embase, and Web of Science were searched on December 31, 2020 for studies that evaluated outcomes in patients with AVM-associated epilepsy after undergoing different treatment modalities. Pooled analysis was performed using a random-effects model and stratified by different modalities.

RESULTS

Forty-nine studies including 2668 patients were included. Interventional management was associated with a 56.0% probability of seizure freedom and a 73.0% probability of seizure improvement. The probability of discontinuing antiepileptic drugs was estimated at 38.0%. The stratified analysis showed that microsurgery was associated with a higher probability of seizure freedom and seizure improvement than was radiosurgery, endovascular, or multimodality treatment. The probability of antiepileptic drug cessation was also higher after microsurgery compared with radiation therapy; however, only clinical but not statistical significance could be inferred because of the lack of comparative analyses.

CONCLUSIONS

Interventional management of AVM-related epilepsy was associated with seizure freedom and seizure improvement in 56% and 73% of cases. Microsurgery seemed to be associated with a higher incidence of seizure freedom and seizure improvement than did other modalities. Future well-designed comparative studies are needed to draw definitive conclusions regarding each modality.

Predictors of seizure control in patients with cerebral arteriovenous malformation

PURPOSE

We aimed to define the predictors of a 2-year seizure-free outcome among patients with cerebral arteriovenous malformation (AVM).

METHODS

A retrospective cohort study recruited patients diagnosed with AVM admitted in the hospital between 2002 and 2020. The demographic data, clinical presentations, seizure semiology, neuro-imaging findings, modality of treatment, and clinical outcomes were compared between the 2-year seizure-free and non-2-year seizure-free groups. A logistic regression model was applied to determine the significant predictors of a 2-year seizure-free outcome.

RESULTS

Of 372 radiologically confirmed patients with cerebral AVM, 105 (28.23%) experienced seizure and a 2-year seizure-free outcome was achieved in 76.19%. Most seizures presented as the initial symptom. Generalized onset seizure was the most common seizure semiology. A nidus diameter < 3 cm (adjusted odds ratio [aOR] 3.102; 95% CI 1.129-9.683; p = 0.046) was the independent predictor of a 2-year seizure-free period, whereas underlying epilepsy (aOR 0.141; 95% CI 0.010-0.688; p = 0.015) was an independent predictor against a 2-year seizure-free outcome.

CONCLUSION

A nidus diameter < 3 cm was the independent predictor of a 2-year seizure-free outcome, whereas underlying epilepsy was the factor against a 2-year seizure-free outcome.

Single-center experience with endovascular treatment of cerebral arteriovenous malformations with intent to cure in pediatric patients

PURPOSE

This study aimed to report the incidence of technical complications and immediate complete angiographic occlusion, identify associated factors with failure of complete occlusion and identify predictors of technical complications in a single-center experience of pediatric arteriovenous malformations (AVM) treated with endovascular treatment with intent to cure.

METHODS

Patients between 1 and 18 years of age undergoing endovascular embolization between 2011 and 2020 were included.

RESULTS

A total of 120 embolizations were performed in 69 patients. The most frequent clinical presentation was intracerebral hemorrhage (76.8%). Immediate obliteration of the malformations was achieved in 40 (58%) cases. The technical complication rate was 15%. AVM nidus size between 3 and 6 cm (OR: 3.91; 95% CI 1.1-13.85; p = 0.035) and the presence of multiple feeders (OR: 5.08; 95% CI 1.41-18.28; p = 0.074) were predictive of failure of immediate complete occlusion. The location of the temporal lobe (OR: 7.83; p = 0.048), deep venous drainage (OR: 4.67; p = 0.112), and the presence of an intranidal aneurysm (OR: 3.58; p = 0.134) were predictors of technical complications.

CONCLUSIONS

Embolization of pediatric AVMs with intent to cure shows a high rate of technical complications and acceptable immediate occlusion rates. Nidus size and the presence of multiple feeders were predictive of failure of complete occlusion, while temporal lobe location, deep venous drainage, and the presence of an intranidal aneurysm were predictors of technical complications. Further studies are needed to determine the best therapeutic approach in the pediatric population.

Complete seizure-free rates following interventional treatment of intracranial arteriovenous malformations: a systematic review and meta-analysis

Seizures are common presenting symptoms of intracranial arteriovenous malformations (AVMs). This systematic review and meta-analysis aims to assess the current evidence regarding complete seizure freedom rates following surgical resection, stereotactic radiosurgery (SRS), and/or endovascular embolization of intracranial AVMs. A systematic review of PubMed, Ovid MEDLINE, and Ovid EMBASE was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Included manuscripts were methodically scrutinized for quality, spontaneous AVM-associated or hemorrhage-associated seizures, complete seizure-free rates following each interventional treatment, follow-up duration; determination methods of seizure outcomes, and average time-to-onset of recurrent seizures after each treatment. Manuscripts that described patients with nondisabling seizures or reduced seizure frequency in their seizure-free calculations were excluded. Seizure freedom rates following surgical resection, SRS, and endovascular embolization were compared via random-effect analysis. Thirty-four studies with a total of 1765 intracranial AVM patients presenting with spontaneous AVM-associated seizures and 408 patients presenting with hemorrhage-associated seizures were qualitatively analyzed. For patients presenting with AVM-associated seizures, the complete seizure-free rates were 73.0% (321/440 patients; 95% CI 68.8-77.1%) following surgical resection, 60.5% (376/622 patients; 95% CI 56.6-64.3%) following SRS, and 44.6% (29/65 patients; 95% CI 32.5-56.7%) following endovascular embolization alone. For patients presenting with either AVM-associated or hemorrhage-associated seizures, the complete seizure-free rates were 73.0% (584/800 patients; 95% CI 69.9-76.1%) following surgical resection, 46.4% (572/1233 patients; 95% CI 43.6-49.2%) following SRS, and 44.6% (29/65 patients; 95% CI 32.5-56.7%) following embolization. For patients presenting with either AVM-associated or hemorrhage-associated seizures, the overall improvements in seizure outcomes regardless of complete seizure freedom were 82.6% (661/800 patients; 95% CI 80.0-85.3%), 70.6% (870/1233 patients; 95% CI 68.0-73.1%), and 70.8% (46/65 patients; 95% CI 59.7-81.1%) following surgical resection, SRS, and embolization, respectively. No study reported information about the time-to-onset for recurrent seizures in any patient following treatment, as seizure outcomes were only described at the last follow-up visit. The available data suggests that surgical resection results in the highest rate of complete seizure freedom. The rate of seizure improvement following surgery increased further to 82.3% when including patients who had improved seizure frequency without achieving true seizure freedom. Complete seizure-free rates following SRS or embolization were more ambiguous and lower when compared to surgical resection. There is a need for high quality studies evaluating AVM treatment modalities and clearly defined seizure outcomes, as the current literature consists mostly of heterogenous patient populations.

Epilepsy Syndromes: Current Classifications and Future Directions

This review describes the clinical presentations and treatment options for commonly recognized epilepsy syndromes in the pediatric age group, based on the 2017 International League Against Epilepsy classification. Structural epilepsies that are amenable to surgical intervention are discussed. Lastly, emerging technologies are reviewed that are expanding our knowledge of underlying epilepsy pathologies and will guide future syndromic classification systems including genetic testing and tissue repositories.

Pre-Surgical Endovascular Proximal Feeder Artery Devascularization Technique for the Treatment of Cranial Arteriovenous Malformations

Objective

Treatment of brain arteriovenous malformations (AVMs) aims to abolish any risk for intracranial hemorrhage with the preservation of the patient’s functional status. We present the technique of pre-surgical endovascular devascularization through proximal feeder artery occlusion for the treatment of cranial AVMs rather than nidus occlusion. Also, we highlight the advantages and the possible clinical indications.

Patients and Methods

Two patients with brain AVM and one patient with scalp AVM were treated by pre-surgical endovascular devascularization followed by surgical resection. Endovascular devascularization was performed by occlusion of the AVM feeders only with Liquid Embolic System Agent (Onyx^®) 18 without entering and filling the nidus. During surgery, feeding arteries colored with the black color of the Liquid Embolic System Agent were clearly identified and cut. Dissection of the AVM was performed, and resection of the nidus was achieved.

Results

Total resection of the AVM was achieved in all cases confirmed with follow-up angiographies, with no neurologic or systemic complications. Also, no major bleeding was detected. In addition, the surgical clips were avoided during surgery. Brain AVMs were safely resected in piecemeal fashion.

Conclusion

Pre-surgical endovascular proximal feeder artery devascularization technique shows to be a safe, simple and effective technique for the management of cranial arteriovenous malformations. This technique simplifies both the endovascular and surgical approaches to complicated cranial AVM cases.

Arteriovenous malformation presenting with epilepsy: a multimodal approach to diagnosis and treatment

Arteriovenous malformation (AVM) presenting with epilepsy significantly impacts patient quality of life, and it should be considered very much a seizure disorder. Although hemorrhage prevention is the primary treatment aim of AVM surgery, seizure control should also be at the forefront of therapeutic management. Several hemodynamic and morphological characteristics of AVM have been identified to be associated with seizure presentation. This includes increased AVM flow, presence of long pial draining vein, venous outflow obstruction, and frontotemporal location, among other aspects. With the advent of high-throughput image processing and quantification methods, new radiographic attributes of AVM-related epilepsy have been identified. With respect to therapy, several treatment approaches are available, including conservative management or interventional modalities; this includes microsurgery, radiosurgery, and embolization or a combination thereof. Many studies, especially in the domain of microsurgery and radiosurgery, evaluate both techniques with respect to seizure outcomes. The advantage of microsurgery lies in superior AVM obliteration rates and swift seizure response. In addition, by incorporating electrophysiological monitoring during AVM resection, adjacent or even remote epileptogenic foci can be identified, leading to extended lesionectomy and improved seizure control. Radiosurgery, despite resulting in reduced AVM obliteration and prolonged time to seizure freedom, avoids the risks of surgery altogether and may provide seizure control through various antiepileptic mechanisms. Embolization continues to be used as an adjuvant for both microsurgery and radiosurgery. In this study, the authors review the latest imaging techniques in characterizing AVM-related epilepsy, in addition to reviewing each treatment modality.

Vascular Abnormalities and the Role of Vascular Endothelial Growth Factor in the Epileptic Brain

Epilepsy is a chronic neurological disorder generally defined to be caused by excessive neuronal activity. Thus, excessive neuronal activity is the main target of the currently used antiepileptic drugs (AEDs). However, as many as 30% of epileptic patients show drug resistance to currently available AEDs, which suggests that epilepsy should be attributed not only to neuronal cells but also to other brain cells, such as glial cells and vascular cells. Astrocytes, pericytes, and endothelial cells in particular comprise the blood–brain barrier (BBB), which tightly regulates the exchange of substances between the brain parenchyma and the circulating blood. It has been proposed that BBB dysfunction, especially barrier leakage, exacerbates epileptic progression, and conversely, that epileptic seizures induce barrier leakage. Furthermore, several studies have shown that BBB dysfunction is one of the main causes of drug resistance in epilepsy. To better understand the mechanisms that link BBB dysfunction and intractable epilepsy to gain insights for the future development of treatments, we review and discuss the relationships between epilepsy and brain vascular abnormalities, mainly by focusing on vascular malformation, BBB dysfunction, and excessive angiogenesis. Because these abnormalities have been reported to be caused by vascular endothelial growth factor (VEGF) in the ischemic brain, we discuss the possible role of VEGF in vascular abnormalities in the epileptic brain, in which the upregulation of VEGF levels has been reported. Both glial cells and endothelial cells express VEGF receptors (VEGFRs); thus, these cells are likely affected by increases in VEGF during seizures, which in turn could cause vascular abnormalities. In this review, we review the possible role of VEGF in epilepsy and discuss the mechanisms that link vascular abnormalities and intractable epilepsy.

Predictors of Epilepsy Presentation in Unruptured Brain Arteriovenous Malformations: A Quantitative Evaluation of Location and Radiomics Features on T2-Weighted Imaging

OBJECTIVE

To explore predictors of epilepsy presentation in unruptured brain arteriovenous malformations (bAVMs) with quantitative evaluation of location and radiomics features on T2-weighted imaging.

METHODS

This retrospective study identified 117 patients with unruptured bAVMs. Cases were randomly split into training dataset (n = 90) and test dataset (n = 27). On the training dataset, we applied atlas-based analysis to identify epilepsy-susceptible brain regions of bAVMs, and then applied the radiomics technique to explore shape, intensity, and textural features that were correlated with epilepsy presentation. Informative radiomics predictors were selected by least absolute shrinkage and selection operator with 3-fold cross-validation. A linear classification score was then constructed, and we tested if we could precisely identify epilepsy-susceptible bAVMs with the location and radiomics predictors.

RESULTS

Two brain regions and 4 radiomics features were screened out as predictors for epilepsy. The percent of damage of the right precentral gyrus and the right superior longitudinal fasciculus was associated with epilepsy presentation. The 4 radiomics features were Original_firstorder_Median, Wavelet-LHL_firstorder_InterquartileRange, Wavelet-HHL_firstorder_InterquartileRange, and Wavelet-HHH_glrlm_RunVariance. Epileptogenic bAVMs had larger variance of run lengths, larger median value, and interquartile range of voxel intensities. On the training dataset, these 6 predictors were able to classify epilepsy-susceptible bAVMs with accuracy at 0.822, and the area under the curve was 0.866 (95% confidence interval, 0.791-0.940). On the test dataset, sensitivity, specificity, and accuracy of classification reached 0.786, 0.769, and 0.778, respectively.

CONCLUSIONS

Epilepsy-susceptible bAVMs had distinct locations and radiomics features on T2-weighted imaging.

Seizure predictors and outcome after Onyx embolization in patients with brain arteriovenous malformations

BACKGROUND

Brain arteriovenous malformation (bAVM)-related epilepsy can significantly affect patient quality of life. We aimed to identify the factors associated with seizures occurrence and evaluate the long-term outcome following Onyx embolization in bAVM patients.

METHODS

Between July 2014 and July 2016, 239 consecutive patients underwent treatment for bAVMs in our institute and were respectively analyzed. Demographics, seizure status and bAVM morphologic characteristics were recorded. Modified Engel classification was used to evaluate the long-term seizure outcomes.

RESULTS

Of 239 bAVM patients, 68 (28.5%) initially presented with seizures. Seizure occurrence was associated with cerebral hemorrhage history, frontal-temporal location and arterial borderzone location. Of the 37 patients who presented with initial seizures and were treated with Onyx embolization, 23 (62.2%) were treated with antiepileptic drugs (AEDs) before Onyx embolization. At the last follow-up visit, 19 (51.4%) of the 37 patients reached modified Engel class I outcome. Of the 23 patients who had ever been treated with AEDs, 12 (52.2%) were still taking AEDs at the last follow-up visit. Single-factor analysis showed that arterial borderzone location was significantly correlated with higher modified Engel class outcome ( p = 0.046).

CONCLUSION

Patients with bAVM hemorrhage history, frontal-temporal location and arterial borderzone location were associated with seizure occurrence. Seizure-free status was not obtained in AVM patients with arterial borderzone after embolization, though it may have benefits in other ways. The seizure-free mechanism of bAVM with Onyx embolization is worth further study.

Bipolar Electrocoagulation on Cortex after AVMs Lesionectomy for Seizure Control

Background:

The findings of previous studies remain controversial on the optimal management required for effective seizure control after surgical excision of arteriovenous malformations (AVMs). We evaluated the efficacy of additional bipolar electrocoagulation on the electrically positive cortex guided by intraoperative electrocorticography (ECoG) for controlling cerebral AVMs-related epilepsy.

Clinical Material and Methods:

Sixty consecutive patients with seizure due to cerebral AVMs, who underwent surgical excision of cerebral AVMs and intraoperative ECoG, were assessed. The AVMs and surrounding hemosiderin stained tissue were completely removed, and bipolar electrocoagulation was applied on the surrounding cerebral cortex where epileptic discharges were monitored via intraoperative ECoG. Patients were followed up at three to six months after the surgery and then annually. We evaluated seizure outcome by using Engel's classification and postoperative complications.

Results:

Forty-nine patients (81.6%) were detected of epileptic discharges before and after AVMs excision. These patients underwent the removal of AVMs plus bipolar electrocoagulation on spike-positive site cortex. After electrocoagulation, 45 patients' epileptic discharges disappeared, while four obviously diminished. Fifty-five of 60 patients (91.7%) had follow-up lasting at least 22 months (mean 51.1 months; range 22-93 months). Determined by the Engel Seizure Outcome Scale, 39 patients (70.9%) were Class I, seven (12.7%) Class II, five (9.0%) Class III, and four (7.2%) Class IV.

Conclusions:

Even alter the complete removal of AVM and sunwinding gliolic and hemosiderin stained tissue, a high-frequency residual spike remained on the surrounding cerebral cortex. Effective surgical seizure control can be achieved by carrying on I additional bipolar electrocoagulation on the cortex guided by the intraoperative ECoG.

Seizures associated with cerebral arteriovenous malformations

Various types of seizures and epilepsy are associated with 20-45% of cerebral arteriovenous malformations (AVMs). The necessity to differentiate between occasional seizures, epilepsy with repetitive seizures, and the much rarer drug-resistant epilepsy (DRE) is underlined. It is clear that where there is frequent seizures or DRE, vascular surgeons should take epilepsy surgery aspects into account. The epidemiology of AVM-associated seizures, assumed pathophysiologic mechanisms, most frequent seizures types, and medical treatment are described. Depending on the severity of the epilepsy, the diagnostic workup, including electroencephalogram (EEG), video-EEG, and, rarely, invasive evaluation, is explained. An invasive presurgical workup is only necessary in rare cases of DRE. The indication to extend the resection to more than just removal of the AVM is defined and the various specific resection techniques for this rare form are outlined. In the vast majority of AVM cases removal of the AVM with some adjoining gliotic or hemosiderotic rim of cortex will be sufficient, however. In the majority of cases with preoperative epilepsy, patients will be seizure-free after surgery. Patients who never had a seizure before AVM removal may develop de novo epilepsy postoperatively (5-15%). Rates of seizure freedom after different treatments (microsurgery, radiosurgery, endovascular) vary.

Seizure control following treatment of brain arteriovenous malformations in pediatric patients

PURPOSE

Seizure outcome after treatment for pediatric patients with arteriovenous malformations (AVMs) has been rarely described in the literature. The aim of this study was to determine the risk factors for seizure presentation in pediatric AVM patients and the predictors for seizure control following treatment.

METHODS

We searched our characteristics of seizures associated with brain arteriovenous malformations prospectively maintained AVM database at Beijing Tiantan Hospital and identified 198 pediatric patients with brain AVMs between the year 2009 and 2014. Seizure presentation, patient characteristics, AVM features, treatment modalities, and postoperative outcomes, especially post-treatment seizure control were collected. Univariate and multivariate logistic regression analyses were applied to determine the risk factors for seizure presentation as well as the predictors for seizure control.

RESULTS

Before initiation of any treatments, 63 (31.8 %) of the overall 198 patients presented with seizure. According to multivariate analyses, larger AVM size, frontal AVM location, and history of prior hemorrhage were significantly associated with seizure presentation (all p < 0.05). For patients with pre-treatment seizure presentation, good seizure outcome was achieved in 73.8 %. AVM obliteration, short-period history of seizure, and short duration for seizure onset were independent predictors of good seizure outcome in the multivariate analysis. For the 135 patients without seizures at presentation, the overall rate of de novo seizures was 4.4 %.

CONCLUSION

In pediatric patients with brain AVMs, prior hemorrhage, larger AVM size, and frontal lobe location may predict subsequent seizures. Highest seizure control can be achieved by complete obliteration of the AVMs with microsurgical resection.

Medical vs. invasive therapy in AVM-related epilepsy: Systematic review and meta-analysis

OBJECTIVE

To compare invasive arteriovenous malformation (AVM) therapy to conservative management using only antiepileptic drugs (AEDs) for achieving seizure freedom in patients with AVM-related epilepsy.

METHODS

We searched Medline, Embase, and Cochrane Central up to June 2015 using epilepsy and AVM Medical Subject Headings and keywords. We included original research involving controlled observational cohort studies or randomized controlled trials (RCTs) comparing seizure outcomes between invasive AVM treatments vs. AED management alone, and uncontrolled case series of invasive AVM therapy for seizures that contained ≥20 patients. The estimates of seizure freedom were pooled using meta-analysis for the controlled trials, while the estimates for the case series were evaluated using descriptive statistics.

RESULTS

Of 2,166 identified abstracts, 98 were reviewed in full text, of which 31 were included in the final dataset. We identified 2 controlled observational studies (n = 106 patients) and 29 uncontrolled case series. We identified 1 RCT but it did not report seizure outcomes. The pooled risk ratio for seizure freedom in controlled studies (0.99; 95% confidence interval [CI] 0.69, 1.43) did not indicate superiority to either approach. Seizure freedom in case series varied from 19% (95% CI 11, 30%) to 95% (95% CI 76, 99%) at last follow-up.

CONCLUSIONS

There is insufficient evidence available to determine if invasive AVM management is superior to AED only for controlling seizures. An RCT of interventional vs. medical management using standardized epilepsy-specific presurgical protocols is warranted.

Factors associated with seizure occurrence and long-term seizure control in pediatric brain arteriovenous malformation: a retrospective analysis of 89 patients

Background

Few studies have examined seizures in pediatric brain arteriovenous malformation. In our study, risk factors associated with seizure occurrence and long-term seizure control outcomes after different treatments in pediatric arteriovenous malformation patients were investigated.

Methods

A retrospective analysis was conducted with clinical data from a cohort of 89 pediatric brain arteriovenous malformation patients acquired between 2008 and 2013. Univariate and multivariate analyses were used to assess risk factors associated with seizure incidence. Patients who presented with seizure before treatment were evaluated using the Engel classification during the follow-up period.

Results

A higher risk of seizure occurrence was observed in large size and unruptured brain arteriovenous malformations using multivariate logistic regression analysis (p < 0.05). A total of 22 children, who presented with seizure before the interventions, were included in subsequent analysis. During a mean follow-up period of 2.3 years after the intervention, 12 (55 %) of these children were classified as Engel class I after treatment.

Conclusions

Seizures were the most common symptom in unruptured bAVMs. Size of the brain arteriovenous malformation is highly significant to seizure occurrence. Patients with cerebral hemorrhage are prone to having an acute seizure occurrence. The different therapies examined all improved seizure control to varying degrees.

Electronic supplementary material

The online version of this article (doi:10.1186/s12883-015-0402-5) contains supplementary material, which is available to authorized users.

Risk of rupture and risks of endovascular management of unruptured brain arteriovenous malformations

This study reports the natural history of unruptured brain arteriovenous malformations (AVMs) and the risks involved in their endovascular management. A total of 242 patients at our center were enrolled in the study, which had retrospective and prospective components. We retrospectively assessed the morbidity and mortality related to endovascular management in 125 patients with unruptured AVMs. We prospectively assessed the natural history of unruptured AVMs in 117 patients with newly diagnosed unruptured AVMs; 48 of the patients had no history of seizure (Group 1), whereas 69 had a history of seizure from the lesion (Group 2). The retrospective group was also divided into patients with and without seizures. The cumulative rate of rupture of AVMs in Group 2 was less than 0.8% per year, while the rate was approximately sixfold higher (5.1% per year) in Group 1. The overall cumulative rate of rupture of AVMs was less than 3.0% per year. The overall rate of endovascular management-related morbidity and mortality was 10.6% in Group 2 and 11.9% in Group 1 at 30 days and was 25.9% and 13.6%, respectively, at one year. There was no independent predictor of a poor endovascular outcome. The likelihood of rupture of unruptured AVMs was exceedingly low among patients in Group 2 and was substantially higher among those in Group 1. The risk of morbidity and mortality related to endovascular management greatly exceeded the six-year risk of rupture among patients in Group 2. Endovascular management of an AVM should not be performed to eliminate or to improve seizure frequency.

Characteristics of brain arteriovenous malformations in patients presenting with nonhemorrhagic neurologic deficits

OBJECTIVE

To identify the specific angioarchitectural characteristics of arteriovenous malformations (AVMs) that are associated with a clinical presentation of nonhemorrhagic neurologic deficits.

METHODS

Between 1999 and 2008, 302 consecutive patients with AVMs were referred to our institution. Twenty-four patients (7.9%) presented with neurologic deficits without hemorrhage before treatment. We tested for statistical associations between angioarchitectural characteristics and neurological deficits at presentation.

RESULTS

When we compared the 24 (7.9%) patients with nonhemorrhagic neurological deficits with the 278 patients who did not experience neurologic deficits initially (total of 302 patients), female sex (P = 0.002), deep AVM location (P = 0.015), AVM size greater than 3 cm (P = 0.001), more than three arterial feeders present (P = 0.004), only perforating feeding artery (P = 0.007), the presence of more than three draining veins (P = 0.016), the presence of varices in the venous drainage (P = 0.013), and a Spetzler-Martin grade of III to V (P = 0.004) were statistically associated with neurological deficits. Patient age, eloquent location, deep venous drainage, venous drainage restriction, and coexisting aneurysms were not statistically associated with neurological deficits without hemorrhage.

CONCLUSION

The characteristics of AVM associated with nonhemorrhagic neurological deficits include female sex, deep AVM location, more than three arterial feeders, only perforating feeding artery, more than three draining veins, the presence of varices in the venous drainage, and a Spetzler-Martin grade of III to V.

Angioarchitecture of brain AVM determines the presentation with seizures: proposed scoring system

BACKGROUND AND PURPOSE

Seizures are a common presentation in patients with brain arteriovenous malformations, but the pathogenesis of seizures remains poorly understood. The purpose of our study was to analyze various morphologic and hemodynamic characteristics of unruptured BAVMs presenting primarily with seizures and, on the basis of these, to propose a scoring system to predict seizures in patients with BAVMs.

MATERIALS AND METHODS

In a retrospective review of our BAVM data base from 2000 to 2009, after excluding patients with ruptured BAVMs, we classified patients into 2 groups, those with and without seizures at presentation. Clinical, angiographic, and hemodynamic characteristics on cerebral angiograms of all these patients were studied. The association between various angioarchitectural variables and seizure presentation was examined, and these results were used to guide the development of criteria to predict presentation with seizures.

RESULTS

Of 1299 patients in our data base, we finally analyzed 33 patients with unruptured BAVMs with seizures and 45 patients with unruptured AVMs without seizures. Location, fistulous component in the nidus, venous outflow stenosis, and the presence of a long pial course of the draining vein were identified as the strongest predictors of seizures. The proposed scoring system had good predictability of presentation with seizures.

CONCLUSIONS

Specific angioarchitectural characteristics of unruptured BAVMs may predict occurrence of seizures and may help in targeted treatment.

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.

Seizure risk with AVM treatment or conservative management: prospective, population-based study

OBJECTIVES

To compare the risk of epileptic seizures in adults during conservative management or following invasive treatment for a brain arteriovenous malformation (AVM).

METHODS

We used annual general practitioner follow-up, patient questionnaires, and medical records surveillance to quantify the 5-year risk of seizures and the chances of achieving 2-year seizure freedom for adults undergoing AVM treatment compared to adults managed conservatively in a prospective, population-based observational study of adults in Scotland, newly diagnosed with an AVM in 1999-2003.

RESULTS

We identified 229 adults with a new diagnosis of an AVM, of whom two-thirds received AVM treatment (154/229; 67%) during 1,862 person-years of follow-up (median completeness of follow-up 97%). There was no significant difference in the proportions with a first or recurrent seizure over 5 years following AVM treatment, compared to the first 5 years following clinical presentation in conservatively managed adults, in analyses stratified by mode of presentation (intracerebral hemorrhage, 35% vs 26%, p = 0.5; seizure, 67% vs 72%, p = 0.6; incidental, 21% vs 10%, p = 0.4). For patients with epilepsy, the chances of achieving 2-year seizure freedom during 5-year follow-up were similar following AVM treatment (n = 39; 52%, 95% confidence interval [CI] 36% to 68%) or conservative management (n = 21; 57%, 95% CI 35% to 79%; p = 0.7).

CONCLUSIONS

In this observational study, there was no difference in the 5-year risk of seizures with AVM treatment or conservative management, irrespective of whether the AVM had presented with hemorrhage or epileptic seizures.

Hemorrhage risk after partial endovascular NBCA and ONYX embolization for brain arteriovenous malformation

OBJECTIVE

To estimate for hemorrhage risk of partially endovascularly embolized brain arteriovenous malformation (BAVM).

METHODS

We retrospectively reviewed 147 consecutive patients with BAVM-treated mainly with endovascular N-butyl cyanoacrylate (NBCA) and ONYX embolization. In Kaplan-Meier survival analysis, the index date was the dated of initial endovascular embolization; cases were censored at time of subsequent intracranial hemorrhage (ICH), or loss to follow-up, and multivariate proportional-hazards regression models included age of presentation (≤30 years old), clinical presentations, and other potential confounders.

RESULTS

We reviewed 147 patients with BAVM (58.8% male; mean age±SD at treatment: 27.5±11.1 years) treated with endovascular embolization. One hundred and forty-four NBCA and 76 ONYX embolizations were performed. Complete obliteration of BAVMs was achieved in 29 patients (19.7%). Thirty-two (21.8%) patients were treated with additional Gamma-knife radiosurgery. During 499.5 years of follow-up, 15 partially treated patients suffered a further hemorrhage, which caused four deaths. The crude annual risk of hemorrhage was 3.0% and the annual death rate was 0.8%. Among partially treated patients with hemorrhage at initial presentation, the risk of hemorrhage was 3.8%, while the risk of hemorrhage for patients without hemorrhage at initial presentation was 2.5%. The annual rate of subsequent hemorrhage was 2.6% for non-ICH and 4.2% for ICH in the partial NBCA embolization group compared with 2.4% for non-ICH and 2.4% for ICH in the partial ONYX embolization group.

CONCLUSIONS

The effect of partial AVM embolization with liquid embolic agents may still be unclear as for risk reduction of annual hemorrhage rate of cerebral AVM.

Complication risk of endovascular embolization for cerebral arteriovenous malformation

OBJECTIVE

The embolic agents currently used for the treatment of AVMs are n-butyl cyanoacrylate (NBCA) and ethylene-vinyl alcohol copolymer (ONYX). The purpose of this study was to examine the overall NBCA and ONYX embolization-related complication rate.

METHODS

We retrospectively reviewed 147 consecutive patients with cerebral AVMs treated mainly with endovascular NBCA and ONYX embolization. Demographics, including age, sex, presenting symptoms, and angiographic factors including AVM size, deep venous drainage, and involvement of eloquent cortex were recorded. Number of pedicles embolized, the obliteration rate, and any complications were recorded. Complications were classified as the following: bleeding and ischemic complications. The ischemic complications were also classified as transient neurologic deficit, and permanent deficits. Modified Rankin Scale (mRS) scores were collected pre- and postembolization on all patients. Univariate regression analysis of determinants of complications was performed.

RESULTS

We reviewed 147 patients with BAVM (58.5% male; mean age±SD at treatment: 27.5±11.1 years) treated with endovascular embolization. Two hundred twenty embolization, 144 NBCA and 76 ONYX embolizations were performed. Complete obliteration of BAVMs were achieved in 29 patients (19.7%). Additional gamma-knife radiosurgery were performed for 32 (21.8%) patients. There were 5 Spetzler-Martin grade I (3.4%), 20 grade II (13.6%), 54 grade III (36.7%), 44 grade IV (30%), and 24 grade V (16.3%) AVMs. There were a total of 7 (4.8% per patient, 3.2% per procedure) complications. There were bleeding complications in 2 patients (1.4% per patient, 0.9% per procedure), transient neurologic deficits in 4 (2.7% per patient, 1.8% per procedure) and 1 permanent deficit (0.7% per patient, 0.5% per procedure). Of the 147 patients, 141 (95.9%) were mRS 0-2, 6 (4.1%) were mRS=3 at discharge. Univariate analysis of risk factors for embolic agent showed that ONYX was not significantly associated with complications (X2=0.3, P>0.5).

CONCLUSIONS

Embolization of brain AVMs is safe, 95.9% of patients had excellent or good outcomes at discharge after AVM embolization using liquid embolic agents, with a complication rate of 4.8%. ONYX embolization was not associated a higher rate of complications comparing with NBCA embolization.