Angioarchitectural characteristics of brain arteriovenous malformations with and without hemorrhage

The incidence of infratentorial arteriovenous malformation-associated aneurysms: an institutional case series and systematic literature review

BACKGROUND

Arteriovenous malformation (AVM)-associated aneurysms represent a high-risk feature predisposing them to rupture. Infratentorial AVMs have been shown to have a greater incidence of associated aneurysms, however the existing data is outdated and biased. The aim of our research was to compare the incidence of supratentorial vs infratentorial AVM-associated aneurysms.

METHODS

Patients were identified from our institutional AVM registry, which includes all patients with an intracranial AVM diagnosis since 2000, regardless of treatment. Records were reviewed for clinical details, AVM characteristics, nidus location (supratentorial or infratentorial), and presence of associated aneurysms. Statistical comparisons were made using Fisher's exact or Wilcoxon rank sum tests as appropriate. Multivariable logistic regression analysis determined independent predictors of AVM-associated aneurysms. As a secondary analysis, a systematic literature review was performed, where studies documenting the incidence of AVM-associated aneurysms stratified by location were of interest.

RESULTS

From 2000-2024, 706 patients with 720 AVMs were identified, of which 152 (21.1%) were infratentorial. Intracranial hemorrhage was the most common AVM presentation (42.1%). The incidence of associated aneurysms was greater in infratentorial AVMs compared with supratentorial cases (45.4% vs 20.1%; P<0.0001). Multivariable logistic regression demonstrated that infratentorial nidus location was the singular predictor of an associated aneurysm, odds ratio: 2.9 (P<0.0001). Systematic literature review identified eight studies satisfying inclusion criteria. Aggregate analysis indicated infratentorial AVMs were more likely to harbor an associated aneurysm (OR 1.7) and present as ruptured (OR 3.9), P<0.0001.

CONCLUSIONS

In this modern consecutive patient series, infratentorial nidus location was a significant predictor of an associated aneurysm and hemorrhagic presentation.

Lesion-Filling Index from Quantitative DSA Correlates with Hemorrhage of Cerebral AVM

BACKGROUND AND PURPOSE

Rupture is the most life-threatening manifestation of cerebral AVMs. This study aimed to explore the hemodynamic mechanism of AVM rupture. We introduced a new quantitative DSA parameter that can reflect the degree of intranidal blood stasis, called the lesion-filling index.

MATERIALS AND METHODS

This study examined patients with AVMs who had undergone both DSA and MR imaging between 2013 and 2014. Clinical presentations, angioarchitecture, and hemodynamic parameters generated from quantitative DSA were analyzed using univariate and multivariable logistic regression. The lesion-filling index was defined as the arterial diagnostic window divided by the volume of the AVM. To assess the correlation between the lesion-filling index and rupture, we incorporated the lesion-filling index into 2 published prediction models widely recognized for predicting AVM rupture risk, R2eD and VALE. The DeLong test was used to examine whether the addition of the lesion-filling index improved predictive efficacy.

RESULTS

A total of 180 patients with AVMs were included. The mean lesion-filling index values in the ruptured group were higher compared with the unruptured group (390.27 [SD, 919.81] versus 49.40 [SD, 98.25]), P < .001). A higher lesion-filling index was significantly correlated with AVM rupture in 3 different multivariable logistic models, adjusting for angioarchitecture factors (OR = 1.004, P = .02); hemodynamic factors (OR = 1.005, P = .009); and combined factors (OR = 1.004, P = .03). Both R2eD (area under the curve, 0.601 versus 0.624; P = .15) and VALE (area under the curve, 0.603 versus 0.706; P < .001) predictive models showed improved predictive performance after incorporating the lesion-filling index and conducting 10-fold cross-validation.

CONCLUSIONS

The lesion-filling index showed a strong correlation with AVM rupture, suggesting that overperfusion is the hemodynamic mechanism leading to AVM rupture.

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.

Unruptured cerebral arteriovenous malformation in children: Outcome in treated and untreated patients

BACKGROUND

The management of unruptured cerebral arteriovenous malformation (URCAVM) is highly controversial; however, data regarding URCAVM in children are scarce.

MATERIAL AND METHODS

We retrospectively reviewed consecutive children followed for URCAVM in our department between 2001 and 2021.

RESULTS

Out of 36 patients, 12 were initially managed by observation, and 24 underwent first-line treatment: 8 by microsurgery, 10 by radiosurgery, 2 by embolization, and 4 by combined treatment. Mean follow-up of the whole group was 63months. Complete cure of the malformation was obtained in 14 patients (58%) in the treatment group: 8/8 in the microsurgery group, 5/10 in the radiosurgery group, 1/4 in the combined treatment group, and none in the embolization group. Two of the initially non-treated patients presented cerebral hemorrhage, with significant neurological consequences. In the treatment group, 5 patients presented new neurological deficits, only 1 of which, however, was functionally significant. Headache improved in 11 cases, mostly in the treatment group. Overall, 6 patients in the treatment group became asymptomatic, versus none in the observation group.

CONCLUSIONS

The treatment of URCAVM is a reasonable option in many pediatric cases, considering the cumulative risk of cerebral hemorrhage during the child's lifetime, as well as the symptoms specific to URCAVM. Microsurgery, when feasible, offers the best functional results and control of the AVM; however, the risk-benefit ratio should be weighed on a case-by-case basis. More studies will be needed to inform treatment decisions in pediatric URCAVM.

Quantitative evaluation of the hemodynamic differences between ruptured and unruptured cerebral arteriovenous malformations using angiographic parametric imaging-derived radiomics features

PURPOSE

Imaging features of cerebral arteriovenous malformations (AVMs) are mainly interpreted according to demographic and qualitative anatomical characteristics. This study aimed to use angiographic parametric imaging (API)-derived radiomics features to explore whether these features extracted from digital subtraction angiography (DSA) were associated with the hemorrhagic presentation of AVMs.

METHODS

Patients with AVM were retrospectively evaluated. Among them, 80% were randomly assigned to a training dataset, and the remaining 20% were assigned to an independent test dataset. Radiomics features were extracted from DSA by API. Then, informative features were selected from radiomics features and clinical features using the Least Absolute Shrinkage and Selection Operator (LASSO) algorithm. A model was constructed based on the selected features to classify the dichotomous hemorrhagic presentation in the training dataset. The model performance was evaluated in the test dataset with confusion matrix-related metrics.

RESULTS

A total of 529 consecutive patients with AVMs between July 2011 and December 2020 were included in this study. After being selected by the LASSO algorithm and analyzed by multivariable logistic regression, three clinical features, namely, age (p = 0.01), nidus size (p < 0.001), and venous drainage patterns (p < 0.001), and four radiomics features were used to construct a model in the training dataset. On the independent test dataset, the model demonstrated a sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 0.852, 0.844, 0.881, 0.809, and 0.849, respectively.

CONCLUSION

The radiomics features extracted from DSA by API could be potential indicators for the hemorrhagic presentation of AVMs.

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

Objective

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

Methods

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

Results

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

Conclusions

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

Microsurgical Treatment of Deep and Eloquent AVMs

Over the past 30 years, the treatment of deep and eloquent arteriovenous malformations (AVMs) has moved away from microneurosurgical resection and towards medical management and the so-called minimally invasive techniques, such as endovascular embolization and radiosurgery. The Spetzler-Martin grading system (and subsequent modifications) has done much to aid in risk stratification for surgical intervention; however, the system does not predict the risk of hemorrhage nor risk from other interventions. In more recent years, the ARUBA trial has suggested that unruptured AVMs should be medically managed. In our experience, although these eloquent regions of the brain should be discussed with patients in assessing the risks and benefits of intervention, we believe each AVM should be assessed based on the characteristics of the patient and the angio-architecture of the AVM, in particular venous hypertension, which may guide us to treat even high-grade AVMs when we believe we can (and need to) to benefit the patient. Advances in imaging and intraoperative adjuncts have helped us in decision making, preoperative planning, and ensuring good outcomes for our patients. Here, we present several cases to illustrate our primary points that treating low-grade AVMs can be more difficult than treating high-grade ones, mismanagement of deep and eloquent AVMs at the behest of dogma can harm patients, and the treatment of any AVM should be tailored to the individual patient and that patient's lesion.

[Relationship between the features of venous drainage of supratentorial arteriovenous malformations and the risk of intracranial hemorrhage]

BACKGROUND

Intracranial hemorrhage is the most common complication of cerebral arteriovenous malformations (AVM). In recent years, most studies devoted to the features of AVM functioning consider venous drainage as important factor influencing the rupture of malformation.

OBJECTIVE

To review the literature data on the relationship between the features of venous drainage of cerebral arteriovenous malformations and intracranial hemorrhage.

MATERIAL AND METHODS

We found 43 studies discussing the features of AVM venous drainage for the period from 1982 to 2020. Most of reports were published between 2005 and 2020.

RESULTS

Deep venous drainage and a single drainage vein were the most significant factors influencing the risk of hemorrhage. Venous ectasia, reflux, stenosis, number, length and tortuosity of drainage veins were less important for the risk of AVM rupture.

CONCLUSION

Analysis of the features of AVM venous drainage can make it possible to predict the natural course of disease and risk of intracranial hemorrhage. These aspects are essential for neurosurgical treatment.

Correlation between angioarchitectural characteristics of brain arteriovenous malformations and clinical presentation of 183 patients

BACKGROUND

The correlation between angioarchitecture and clinical presentation of brain arteriovenous malformation (bAVM) remains a subject of debate.

OBJECTIVE

The main purpose of the present study was to assess the correlation between angioarchitectural characteristics of bAVM and clinical presentation.

METHODS

A retrospective review of all consecutive patients presenting a bAVM who underwent a cerebral angiography at Beneficencia Portuguesa Hospital in São Paulo between January 2006 and October 2016 was carried out. Patients were divided in five groups: group 1 - hemorrhage; group 2 - seizure; group 3 - headache; group 4 - progressive neurological deficits (PND); group 5 - incidental).

RESULTS

A total of 183 patients were included, with group 1 comprising 56 cases, group 2 49 cases, group 3 41 cases, group 4 28 cases, and group 5 9 cases. Regarding hemorrhage presentation, a statistical correlation was observed with female gender (P < 0.02), Spetzler-Martin 3B (P < .0015), and lesions with low flow (P < 0.04). A positive association was found between group 2 and age less than 36 years (P < 0.001), male sex (P < 0.018), presence of superficial lesions not classified as SM 3B (P < 0.002), presence of venous ectasia (p <0.03), and arterial steal phenomenon (P < 0.03). Group 4 was associated with older age (P < 0.01).

CONCLUSIONS

Angioarchitectural characteristics can be correlated with some clinical presentations as well as with some clinical data, making it possible to create predictive models to differentiate clinical presentations.

Current concepts and perspectives on brain arteriovenous malformations: A review of pathogenesis and multidisciplinary treatment

Brain arteriovenous malformations (bAVMs) are unusual vascular pathologies characterized by the abnormal aggregation of dilated arteries and veins in the brain parenchyma and for which the absence of a normal vascular structure and capillary bed leads to direct connections between arteries and veins. Although bAVMs have long been believed to be congenital anomalies that develop during the prenatal period, current studies show that inflammation is associated with AVM genesis, growth, and rupture. Interventional treatment options include microsurgery, stereotactic radiosurgery, and endovascular embolization, and management often comprises a multidisciplinary combination of these modalities. The appropriate selection of patients with brain arteriovenous malformations for interventional treatment requires balancing the risk of treatment complications against the risk of hemorrhaging during the natural course of the pathology; however, no definitive guidelines have been established for the management of brain arteriovenous malformations. In this paper, we comprehensively review the current basic and clinical studies on bAVMs and discuss the contemporary status of multidisciplinary management of bAVMs.

Update Onyx embolization for plexiform arteriovenous malformation: Ante-grade drifting technique

OBJECTIVE

The conventional arteriovenous malformation (AVM) Onyx embolization technique is the extrusion Onyx injection technique, with blood-flow control after a certain distance casting through the head end of the microcatheter. This method has elevated periprocedural AVM bleeding complications. In this study, the authors reported safety and efficacy of an updated ante-grade drifting Onyx injection for plexiform AVM embolization.

METHODS

Between January 2016 and December 2018, 101 consecutive patients with plexiform AVMs were treated with ante-grade drifting Onyx injection. The patients' clinical status was classified using the modified Rankin Scale (mRS). To measure associations, logistic univariate or multivariate regression analyses were used.

RESULTS

Complete AVM obliteration was achieved in 51.2% (52/101) of patients. Two (2/101, 2.0%) arterial perforations occurred without causing neurological deficits. In univariate and multivariate logistic regression analyses, younger patient age (odds ratio (OR) = 1.06, 95% confidence interval (CI) 1.01-1.12, p = 0.014), haemorrhagic presentation at admission (OR = 7.14, 95% CI 1.52-33.33, p = 0.013) and low Spetzler-Martin grade (OR = 10.00, 95% CI 3.45-25.00, p < 0.001) were significantly correlated with complete obliteration. Pretreatment mRS was correlated with perforation complication (OR = 3.44, 95% CI 1.05-11.29, p = 0.041) in univariate logistic regression analysis but not in multivariate logistic regression analysis (OR = 2.956, 95%CI 0.745, 11.731, p = 0.123). Patients' clinical status was significantly improved after endovascular AVM embolization.

CONCLUSIONS

With ante-grade drifting Onyx injection, it was possible to prevent serious bleeding complications and elevated complete embolization rate in plexiform AVMs. Younger patient age, haemorrhagic presentation at admission and low AVM Spetzler-Martin grade were significantly correlated with complete obliteration. Although there is not enough statistical power to show that the pretreatment mRS and the arterial perforation complication have a significant correlation, but its OR value is large, and there may be more data in the future to obtain further conclusion.

Is smoking a risk factor for bleeding in adult men with cerebral arteriovenous malformations? A single-center regression study from China

OBJECTIVE

To assess whether smoking increases the risk of bleeding in patients with cerebral arteriovenous malformations (CAVM).

MATERIAL AND METHODS

According to our research plan, 385 CAVM patients admitted to Beijing Tiantan Hospital from December 2015 to January 2018 were included in this study, including 210 bleeding patients and 175 non-bleeding patients. We divided patients into three subgroups of current smokers, ex-smokers (those who quit smoking for one year or more) and non-smokers. The relationship between smoking and the risk of CAVM rupture was assessed by univariate and multivariate regression analysis.

RESULTS

Multivariate regression analysis showed that there was a statistically significant difference between current smoker and non-smoker (OR = 1.87, p = 0.019). Among the covariates of the multivariate regression analysis, the location, combined with blood flow-related intracranial aneurysms and size were related to the risk of CAVM bleeding.

CONCLUSION

Current smoking may increase the risk of CAVM bleeding; however, there was no significant correlation between ex-smoking and CAVM bleeding.

Targeted Embolization of Aneurysms Associated With Brain Arteriovenous Malformations at High Risk for Surgical Resection: A Case-Control Study

BACKGROUND

High-risk components of brain arteriovenous malformations (BAVMs) can be targeted to reduce the risk of lesion rupture.

OBJECTIVE

To evaluate targeted embolization of aneurysms against other means of treatment with a case-control analysis; we previously investigated this approach associated with BAVMs.

METHODS

Retrospective analysis of patients with BAVMs was performed, identifying patients treated with intention to occlude only an aneurysm associated with a BAVM. For each targeted aneurysm embolization (TAE) patient identified, 4 control patients were randomly selected, controlling for rupture status, age, and Spetzler-Martin plus Lawton-Young supplemental score. Analysis was performed to compare rates of adverse events (hemorrhage, new seizure, and death) between the 2 groups.

RESULTS

Thirty-two patients met inclusion criteria, and 128 control patients were identified, out of 1103 patients treated during the study period. Thirty-four adverse events occurred (15 ruptures, 15 new seizures, and 11 deaths) during the follow-up period (mean 1157 d for the TAE cohort and 1036 d for the non-TAE cohort). Statistically lower associations were noted for the TAE group for any adverse event (hazard ratio 0.28, P = .037) and the composite outcome of hemorrhage or new seizure (hazard ratio 0.20, P = .029).

CONCLUSION

For BAVMs at high risk for surgical resection, TAE can be performed safely and effectively. Patients treated with TAE had better outcomes than matched patients undergoing other combinations of treatment. TAE can be considered for BAVMs with high operative risk prior to radiosurgery or when no other treatment options are available.

Risk factors for hemorrhage of brain arteriovenous malformation

Patients with brain arteriovenous malformation (bAVM) are at risk of intracranial hemorrhage (ICH). Overall, bAVM accounts for 25% of hemorrhagic strokes in adults <50 years of age. The treatment of unruptured bAVMs has become controversial, because the natural history of these patients may be less morbid than invasive therapies. Available treatments include observation, surgical resection, endovascular embolization, stereotactic radiosurgery, or combination thereof. Knowing the risk factors for bAVM hemorrhage is crucial for selecting appropriate therapeutic strategies. In this review, we discussed several biological risk factors, which may contribute to bAVM hemorrhage.

R2eD AVM Score

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

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

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

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Endovascular Therapy for Brainstem Arteriovenous Malformations

Brainstem arteriovenous malformations (AVMs) represent ∼5% of all intracranial AVMs and carry a higher risk of hemorrhage than their supratentorial counterparts. There is a high and near-uniform mortality with initial and recurrent episodes of hemorrhage. Brainstem AVMs may also present symptomatically with focal neurologic deficits or hydrocephalus. Treatment is indicated for ruptured and symptomatic brainstem AVMs, as well as those possessing high-risk angioarchitectural features. Microsurgical resection and stereotactic radiosurgery are ideal therapeutic options when feasible. Embolization is most commonly used as adjunctive treatment before surgery or stereotactic radiosurgical irradiation. Preoperative embolization facilitates microsurgical resection and reduces intraoperative and postoperative hemorrhage rates. Use of embolization preradiosurgically helps to reduce nidal size, transforming a large lesion to a size amenable to radiosurgical intervention, increasing the probability of obliteration, decreasing procedural hemorrhage risk, stabilizing the lesion until radiotherapeutic effect achieves obliteration, and providing interval symptomatic resolution. Embolization may also be used effectively as stand-alone monotherapy for small lesions with 1 or 2 arterial feeders not supplying eloquent parenchyma. Although an extensive evidence base exists for clinical usefulness of stereotactic radiosurgery as monotherapy or in combination with other therapeutic modalities, only a few studies have reported specifically on obliteration and complication rates with monotherapeutic embolization in the treatment of brainstem AVMs. The potential role of embolization as monotherapy for brainstem AVMs is reviewed and discussed.

The Effect of Flow-Related Aneurysms on Hemorrhagic Risk of Intracranial Arteriovenous Malformations

BACKGROUND

Previous reports indicated an association between hemorrhagic presentation and flow-related aneurysms in arteriovenous malformation (AVM) patients. However, it remains unclear whether these flow-related aneurysms result in the hemorrhage of AVM.

OBJECTIVE

To characterize this hemorrhage risk using our institutional experience over 25 yr.

METHODS

We retrospectively reviewed records of patients at our institution diagnosed with AVM from 1990 to 2015. Patients without associated aneurysms (AVM only) and those with flow-related aneurysms (AVM-FA) were compared. Those with intranidal or unrelated aneurysms were excluded. Annual risk of AVM-related hemorrhage was calculated using the birth-to-treatment approach and compared using Poisson rate ratio test.

RESULTS

Among 526 patients, there were 457 AVM only patients and 69 with flow-related aneurysms. AVM-FA patients were older (P = .005). AVMs with flow-related aneurysms were more likely located in the cerebellar vermis and hemispheres (P = .023 and .001, respectively). Presence of flow-related aneurysms increased the risk of presentation with subarachnoid hemorrhage (P < .001). Interestingly, no significant differences in presenting hemorrhage due to AVM rupture were found (P > .356). The majority of aneurysms were untreated (69.5%), and only 8 (9.8%) had ruptured presentation. At follow-up (mean = 5.3 yr), patients with flow-related aneurysms were less likely to develop seizures (P = .004). The annual risk of AVM hemorrhage was 1.33% and 1.05% for AVM only patients and AVM-FA patients, respectively (P = .248).

CONCLUSION

Despite increased risk of subarachnoid hemorrhage at presentation, there was no increased likelihood of rupture in AVMs with flow-related aneurysms. More studies are warranted, as clarifying the competing risks of AVM vs aneurysm rupture may be critical in determining optimal treatment strategy.

Review of de novo cerebral arteriovenous malformation: haemorrhage risk, treatment approaches and outcomes

Objective A small number of patients has been reported to develop a completely new or de novo arteriovenous malformation (AVM) after brain surgery, haemorrhage, head trauma or ischaemic stroke. The natural history of these lesions is unknown. In this review, both ruptured and unruptured de novo AVMs and their treatments were reviewed. Methods Published literature in the PubMed database citing 'de novo cerebral arteriovenous malformation' was reviewed. Additional studies were identified through reference searches in each reviewed article. A review was performed using all published cases, the treatment approaches and outcomes. Results A total of 38 patients, including 37 de novo AVMs reported from 1988 to 17 November 2017 and our one patient, was collected. The age at AVM diagnosis was 5-73 years (mean ± SD, 27.6 ± 20.5 years). The duration time, from negative examination to AVM diagnosis, was 2 months to 25 years (mean ± SD, 6.6 ± 4.9 years). The presentation of de novo AVM was headaches in three (7.9%) patients, bleedings in 12 (31.6%), incidental in 14 (36.8%) and seizure in nine (23.7%). The estimated risk of haemorrhage was 4.8% per year. Seventeen (44.7%) patients were treated with surgical resection, 10 (26.3%) were conservatively observed, nine (23.7%) were treated with radiosurgery and two (5.3%) were endovascularly embolised. The morbidity and mortality were reported as 5.3% and 7.9%, respectively. Conclusion Post-natal de novo AVMs have been reported. Their annual haemorrhage risk is 4.8%. Most of them are treated by surgical resection and are associated with morbidity and mortality.

Embolization of feeding arteries and symptom alleviation of mixed dural-pial arteriovenous malformations

Background

To examine whether embolization of dural or pial blood supply branch is more efficient for symptom alleviation for unruptured mixed dural-pial arteriovenous malformations (DPAVMs).

Methods

We retrospectively reviewed 30 DPAVM patients from a database of 425 consecutive cerebral arteriovenous malformation (CAVM) patients who underwent endovascular embolization between January 2010 and December 2015 at our institution. Demographics, angioarchitectural characteristics, endovascular embolization details and patients clinical outcomes were recorded. The modified Rankin Scale (mRS), Engel‘s classification and Visual Analogue pain scale (VAS) were used to assess clinical outcomes.

Results

The single center cohort data shows that the incidence of DPAVM is 7.1%. Among the 30 DPAVM patients, 9 (30.0%) are ruptured and 21 (70.0%) are unruptured. Four (19.0%) of the 21 unruptured DPAVM patients are failed to follow-up, leaving 17 to analysis the clinical outcomes. Clinical presentations of the 17 unruptured DPAVM patients are epilepsy (n = 10), headache (n = 5) and focal neurological dysfunction (n = 2). Six patients have DPAVMs occluded via pial blood supply branches, 4 via dural branches and 7 via both pial and dural branches. Unruptured DPAVM patients with nidus occluded via dural blood supply branches, or both pial and dural branches have higher symptom alleviation rate than patients with nidus occluded via pial branches (100%/85.7% vs 66.7%).

Conclusions

For DPAVM patients presented with epilepsy, headache and FND, embolization via dural blood supply branches may be more efficient for symptom alleviation. Large cohort study is needed to confirm the generalizability.

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

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

Transvenous retrograde AVM embolization: Indications, techniques, complications and outcomes

Objective Transvenous retrograde arteriovenous malformation (AVM) embolization (TRAE) has been proposed. The present study was to review the techniques, their conjunctions and effectiveness. Methods Eligible related articles were identified by searching the PubMed and Web of Science databases using "transvenous" and "arteriovenous malformation." Results A total of 16 eligible studies, with 60 cases of AVM treated with TRAE, were analyzed. Prior to TRAE procedure, transarterial Onyx 18 was performed in 23 (38.3%), cyanoacrylate in three (5%) and coiling in two (3.3%), neurosurgery in one (1.7%) and radiosurgery in three (5%). These prior treatments were used to reduce the size of the nidus to <3 cm and TRAE was performed. One anterior choroidal artery aneurysm was coiled before TRAE. Systemic hypotension (blood pressure<100 mmHg) occurred in six (10%) patients and local hypotension (proximal arterial temporary balloon protection) in five (8.3%) patients. Complete obliteration was achieved in 56 (93.3%) AVMs, four (6.7%) with residual, of which one was supplemented with radiosurgery. During mean one-year follow-up (1 month to 3.2 years), there were five cases (8.3%) of permanent disability and one (1.7%) mortality resulting from initial hemorrhage. Fifty-four (90%) patients were independent (mRS ≤ 2) at follow-up. Ruptured AVMs and Spetzler-Martin I-III were associated with a high cure rate. Conclusion According to previous reports, selected AVMs could undergo TRAE. TRAE is safe and curative with Onyx after the nidus size is reduced sufficiently by transarterial embolization, neurosurgery or radiosurgery, with or without the aid of proximal arterial temporary balloon protection.

Known and unknown cerebral arteriovenous malformations in pregnancies: haemorrhage risk and influence on obstetric management

Objective The objective of this study was to evaluate the haemorrhage risk of known and unknown cerebral arteriovenous malformations and their obstetric management. Methods A retrospective review was performed and analysed 67 consecutive cases of arteriovenous malformation with pregnancy history. Results Sixty-seven cases of arteriovenous malformation with pregnancy histories were identified. In 14 cases (20.9%) of arteriovenous malformation diagnosed before pregnancy, 11 cases were treated (10 embolisation and one surgery), there was no haemorrhage in 14 pregnancies, 14 healthy babies were delivered by caesarean section in 12 pregnancies (85.7%) and vaginal delivery in two pregnancies (14.3%). In 53 cases (89.1%) of arteriovenous malformation diagnosed during/after pregnancy, there was one (1.6%) case of subarachnoid haemorrhage at 38 weeks' gestation in 64 pregnancies, 64 healthy babies were delivered by caesarean section in 11 pregnancies (17.2%) and vaginal delivery in 53 pregnancies (82.8%). This resulted in 1.6% (95% confidence interval 0-4.6%) haemorrhage rate per pregnancy in unknown arteriovenous malformations. Known arteriovenous malformation gravida was prone to caesarean section; however, vaginal delivery did not increase the haemorrhage risk in unknown arteriovenous malformation gravidas (1.8% vs. 0%, P = 1.000). Conclusion Prior treatment for ruptured arteriovenous malformation could prevent its haemorrhage during pregnancy and the haemorrhage risk of unruptured arteriovenous malformation in pregnancies is low. Although known arteriovenous malformation gravida is prone to caesarean section, vaginal delivery seems not to increase the haemorrhage risk in unknown arteriovenous malformation gravidas.

Critical review of brain AVM surgery, surgical results and natural history in 2017

BACKGROUND

An understanding of the present standing of surgery, surgical results and the role in altering the future morbidity and mortality of untreated brain arteriovenous malformations (bAVMs) is appropriate considering the myriad alternative management pathways (including radiosurgery, embolization or some combination of treatments), varying risks and selection biases that have contributed to confusion regarding management. The purpose of this review is to clarify the link between the incidence of adverse outcomes that are reported from a management pathway of either surgery or no intervention with the projected risks of surgery or no intervention.

METHODS

A critical review of the literature was performed on the outcomes of surgery and non-intervention for bAVM. An analysis of the biases and how these may have influenced the outcomes was included to attempt to identify reasonable estimates of risks.

RESULTS

In the absence of treatment, the cumulative risk of future hemorrhage is approximately 16% and 29% at 10 and 20 years after diagnosis of bAVM without hemorrhage and 35% and 45% at 10 and 20 years when presenting with hemorrhage (annualized, this risk would be approximately 1.8% for unruptured bAVMs and 4.7% for 8 years for bAVMs presenting with hemorrhage followed by the unruptured bAVM rate). The cumulative outcome of these hemorrhages depends upon whether the patient remains untreated and is allowed to have a further hemorrhage or is treated at this time. Overall, approximately 42% will develop a new permanent neurological deficit or death from a hemorrhagic event. The presence of an associated proximal intracranial aneurysm (APIA) and restriction of venous outflow may increase the risk for subsequent hemorrhage. Other risks for increased risk of hemorrhage (age, pregnancy, female) were examined, and their purported association with hemorrhage is difficult to support. Both the Spetzler-Martin grading system (and its compaction into the Spetzler-Ponce tiers) and Lawton-Young supplementary grading system are excellent in predicting the risk of surgery. The 8-year risk of unfavorable outcome from surgery (complication leading to a permanent new neurological deficit with a modified Rankin Scale score of greater than one, residual bAVM or recurrence) is dependent on bAVM size, the presence of deep venous drainage (DVD) and location in critical brain (eloquent location). For patients with bAVMs who have neither a DVD nor eloquent location, the 8-year risk for an unfavorable outcome increases with size (increasing from 1 cm to 6 cm) from 1% to 9%. For patients with bAVM who have either a DVD or eloquent location (but not both), the 8-year risk for an unfavorable outcome increases with the size (increasing from 1 cm to 6 cm) from 4% to 35%. For patients with bAVM who have both a DVD and eloquent location, the 8-year risk for unfavorable outcome increases with size (increasing from 1 cm to 3 cm) from 12% to 38%.

CONCLUSION

Patients with a Spetzler-Ponce A bAVM expecting a good quality of life for the next 8 years are likely to do better with surgery in expert centers than remaining untreated. Ongoing research is urgently required on the outcome of management pathways for bAVM.

Comparison of Hemorrhagic Risk in Intracranial Arteriovenous Malformations Between Conservative Management and Embolization as the Single Treatment Modality

BACKGROUND

Embolization has been discussed as a feasible single modality treatment for intracranial arteriovenous malformations (AVMs).

OBJECTIVE

To compare hemorrhagic risk between embolization and conservative management in a multivariate survival analysis.

METHODS

We retrospectively reviewed records of patients with intracranial AVMs evaluated at our institution from 1990 to 2013. We included patients recommended to undergo embolization without other treatment modalities and patients managed conservatively. Multivariate Cox regression analysis of hemorrhage-free survival was performed, with the survival interval right-censored to date of either last follow-up or salvage treatment.

RESULTS

We identified 205 patients matching our inclusion criteria, with 160 patients in the noninterventional group and 45 in the embolization group. The average age of all patients was 40.2 ± 19.5 yr, with younger patients undergoing embolization more often (P = .026). Fifty-one (31.9%) conservatively managed patients and 13 (28.9%) patients treated by embolization (P = .703) presented with hemorrhage. Other baseline characteristics were similar between the 2 management groups. During an average follow-up period of 7.7 yr, 30 patients (14.6%) experienced hemorrhage recurrence. Multivariate Cox regression revealed older age (P = .031) and hemorrhagic presentation (P &lt; .001) to be statistically associated with follow-up hemorrhage. In a subset analysis of unruptured AVMs, embolization was associated with a 4-fold hazard ratio of hemorrhage compared to conservative management (P = .044).

CONCLUSION

Older age and initial presentation with hemorrhage were associated with increased risk of hemorrhage during follow-up. Treatment of AVMs with embolization as the sole modality may increase hemorrhagic risk compared with conservative management, especially in unruptured AVMs.

Contemporary Imaging of Cerebral Arteriovenous Malformations

OBJECTIVE

Brain arteriovenous malformation (AVM) rupture results in substantial morbidity and mortality. The goal of AVM treatment is eradication of the AVM, but the risk of treatment must be weighed against the risk of future hemorrhage.

CONCLUSION

Imaging plays a vital role by providing the information necessary for AVM management. Here, we discuss the background, natural history, clinical presentation, and imaging of AVMs. In addition, we explain advances in techniques for imaging AVMs.

Arteriovenous malformations: epidemiology, clinical presentation, and diagnostic evaluation

Brain arteriovenous malformations (AVMs) represent an uncommon disease of the central nervous system characterized by an arteriovenous shunt in which one or multiple arterial pedicles feed into a vascular nidus, creating early drainage into a venous outflow channel. These lesions are considered to be congenital and can come to clinical attention in a variety of ways such as seizure, intracranial hemorrhage, chronic headache or progressive neurological deficit. We focus on the epidemiology, clinical presentation and diagnostic evaluation in this chapter.

Long-term hemorrhagic risk in pediatric patients with arteriovenous malformations

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

Characteristics of etiological diagnostic workup across the past 10 years in patients with spontaneous intracerebral hemorrhage in a large general hospital

OBJECTIVE

A swift and accurate diagnosis of etiology would lay the foundation of targeted management for patients with spontaneous intracerebral hemorrhage (SICH). It is unclear what the status of diagnostic workup related to etiology is in Chinese hospitals which treat the majority of the hemorrhagic patients in the world. We aim to demonstrate characteristics on diagnostic workup implemented routinely in both departments of Neurology and Neurosurgery in patients with SICH.

METHODS

We enrolled patients with SICH from March 2002 to December 2011 from Chengdu stroke registry. Data on diagnostic workup were extracted.

RESULTS

A total of 2264 patients diagnosed as SICH with rapid neuroimaging (computed tomography (CT) or magnetic resonance imaging (MRI)) scan were included. Patients in the department of Neurosurgery had a lower median Glasgow Coma Scale (GCS) score and a longer median length of stay. They had a significantly lower proportion of hyperlipidemia and heart disease, but a higher proportion of hypertension, alcohol consumption and history of stroke (all p < 0.05). Following diagnostic workups were more frequently undertaken in the Neurological Department than in the neurosurgical Department: digital subtraction angiography (DSA), plain CT, plain MRI, carotid duplex ultrasound (all p < 0.001). However, computed tomography angiography (CTA), contrast-enhanced MRI, and brain biopsy (all p < 0.001) were implemented more in the Neurosurgical Department. While no difference in the proportion of magnetic resonance angiography (MRA) was found between the two departments, the intracranial vascular imaging (workup contains at least one of CTA, MRA and DSA) was performed more frequently in the Department of Neurosurgery (29.8% vs. 9.1%, p < 0.001). The independent predictors contribute to the implementation of vascular examinations were gender, age, GCS score on admission, department of patients admitted in and the year patients were hospitalized in (all p < 0.05).

CONCLUSIONS

Younger patients, females, with severe stroke onset (evaluated by GCS score), admitted in Department of Neurosurgery and hospitalized in recent years had undertaken more examinations on intracranial vascular. It is an urgency to explore a practical scheme of diagnostic workup for the etiology of SICH.

Multicenter assessment of morbidity associated with cerebral arteriovenous malformation hemorrhages

Background

The optimal management strategy for unruptured cerebral arteriovenous malformations (AVMs) is controversial since the ARUBA trial (A Randomized trial of Unruptured Brain AVMs). An accurate understanding of the morbidity associated with AVM hemorrhages may help clinicians to formulate the best treatment strategy for unruptured AVMs.

Objective

To determine the morbidity associated with initial cerebral AVM rupture in patients presenting to tertiary medical centers.

Methods

Retrospective chart reviews from three tertiary academic medical centers were performed for the period between 2008 and 2014. All patients admitted with intracranial hemorrhage due to untreated AVMs were included in this study. Patient-specific variables, including demographics, imaging characteristics, neurologic examination results, and clinical outcome, were analyzed and recorded.

Results

101 Patients met the inclusion criteria. Admission National Institutes of Health Stroke Scale (NIHSS) scores were 0, 1–9, and ≥10 in 26%, 29%, and 45% of patients, respectively. Hematoma locations were subarachnoid, intraventricular, intraparenchymal, and combined in 5%, 11%, 32%, and 52% of patients, respectively. Deep venous drainage was present in 43% of AVMs; AVM-associated aneurysms were present in 44% of patients. Emergent hematoma evacuations were performed in 37% of patients and 8% of patients died while in hospital. At discharge, of those who survived, NIHSS scores of ≥1 and ≥10 were found in 69% and 23%, respectively. At the 90-day follow-up, 34% had a modified Rankin Scale (mRS) score >2. Patients with admission NIHSS score ≥10 had significantly higher rates of midline shift, surgical hematoma evacuation, and follow-up mRS ≥3 (p<0.05).

Conclusions

The morbidity associated with cerebral AVM rupture appeared to be higher in our study than previously reported. Morbidity from AVM rupture should be considered as an important factor, together with variables such as risk of AVM rupture and procedural risk, in determining the optimal treatment strategy for unruptured cerebral AVMs.

Less can be more: Targeted embolization of aneurysms associated with arteriovenous malformations unsuitable for surgical resection

INTRODUCTION

To mitigate risks of hemorrhage, high-risk features of brain arteriovenous malformations (BAVMs) can be targeted to reduce the risk of rupture. Previous investigation has examined embolization of a pedicle supplying a high-risk feature; this study examines embolization targeted specifically at aneurysms associated with BAVMs.

MATERIALS AND METHODS

Patients with BAVMs treated at two high-volume neurointerventional services were retrospectively reviewed. Patients treated with intention to occlude only the associated aneurysm itself were analyzed. Demographic and lesion characteristics were identified, as were technical and clinical outcomes. Adverse events were defined as hemorrhage, new seizure, and death.

RESULTS

Thirty-two patients met inclusion criteria out of 1103 patients treated during the study period. Twenty-seven (84.4%) BAVMs were acutely ruptured, all with the aneurysm identified as the hemorrhage source. Twenty-four (75.0%) lesions involved eloquent territory. There were equal numbers of feeding artery and nidus aneurysms. Follow-up data were available for a total of 101.3 patient-years for a mean follow-up time of 2.9 years. One patient died; the remaining 31 patients had improved functional status at last contact. Annualized rate of hemorrhage after treatment was 1.0%; rate of adverse events after treatment was 3.0%. Excluding time after confirmed occlusion following radiosurgery, annualized rates were 1.4% and 4.8%, respectively.

CONCLUSION

In inoperable BAVMs, targeted embolization of associated aneurysms can be performed safely and effectively. This should be considered in high-risk lesions prior to radiosurgery or in cases when no other treatment options are available. Such intervention warrants further investigation.

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

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

Long-term Outcomes of Patients With Giant Intracranial Arteriovenous Malformations

BACKGROUND:

Giant intracranial arteriovenous malformations (AVMs) are rare cerebrovascular lesions that pose management challenges.

OBJECTIVE:

To further clarify outcomes in patients with giant cerebral AVMs managed with conservative or interventional therapies.

METHODS:

We performed a retrospective review of all patients diagnosed with AVMs evaluated at our institution from 1990 to 2013. Patients with a single intracranial AVM &gt;6 cm were included. Patients were divided into 2 groups: conservative management or intervention (microsurgery, radiosurgery, or embolization). Functional outcome was assessed with the modified Rankin Scale (mRS) and compared between the 2 groups.

RESULTS:

A total of 55 patients with giant AVMs were included, and 35 patients (63.6%) had clinical follow-up with a mean of 11.8 years. Spetzler-Martin grades were as follows: grade III, n = 2 (3.6%); grade IV, n = 15 (27.3%); and grade V, n = 38 (69.1%). Twenty-four patients (43.6%) were conservatively managed. The patients in the conservatively managed group had larger AVMs (P &lt; .05) with more frequent involvement of the temporal lobe (P = .02). Five patients (26.3%) in the conservatively managed group and 5 (31.3%) in the intervention group experienced hemorrhage during follow-up, translating to an annualized risk of 2.7% and 4.1%, respectively. No significant difference in risk of first subsequent hemorrhage was observed (P = .78). Despite comparable mRS scores at presentation, we observed a trend toward better outcomes (mRS &lt; 2) in patients undergoing conservative management (P = .06) compared with the intervention group at last follow-up.

CONCLUSION

This study suggests that interventions for giant AVMs should be considered cautiously because hemorrhagic risk is similar regardless of management strategy and functional outcome is likely to be same or better in the conservatively managed population.

Patient Age, Hemorrhage Patterns, and Outcomes of Arteriovenous Malformation

BACKGROUND

The angioarchitecture and presentation of arteriovenous malformations (AVMs) associated with AVM hemorrhage may vary with patient age. Our aim was to determine the influence of patient age at diagnosis on hemorrhage patterns and outcomes.

METHODS

A consecutive case series of 267 cases of ruptured AVMs was retrospectively analyzed. Hemorrhage patterns (intracerebral hemorrhage, subarachnoid hemorrhage, and intraventricular hemorrhage) were confirmed based on computed tomography imaging at initial diagnosis. Clinical outcomes were classified with a modified Rankin Score. These cases were analyzed with respect to age at diagnosis, hemorrhage patterns, Spetzler-Martin grades, and their clinical outcomes.

RESULTS

During a mean 22.2 months follow-up time (range, 7 hours to 10 years), 212 cases (79.4%) were favorable (modified Rankin Score ≤2) and 55 cases (21.6%) were unfavorable (modified Rankin Score ≥3). The mean age was higher in patients with an unfavorable outcome at follow-up. In univariate analyses, different age groups were significantly associated with bleeding patterns (P = 0.022). Unfavorable outcome was associated with intracerebral hemorrhage (odds ratio, 0.330; 95% confidence interval, 0.142-0.768; P = 0.008) and evacuation of hematoma (odds ratio, 0.195; 95% confidence interval, 0.044-0.867; P = 0.025), whereas intraventricular hemorrhage, subarachnoid hemorrhage, and intraventricular drainage were significantly associated with a favorable outcome. Different age groups were not significantly associated with bleeding patterns, sex, and the location of the AVM, and Spetzler-Martin grades did not show a significant association with the severity of outcomes.

CONCLUSIONS

Different age groups were significantly associated with bleeding patterns. Higher patient age, intracerebral hemorrhage, and evacuation of hematoma seem to be associated with an unfavorable outcome after AVM rupture.

Spontaneous Thrombosis of a Ruptured Brain Arteriovenous Malformation: The Argument for Early Conservative Management

Generally, definitive treatment of brain arteriovenous malformations (BAVM) presenting with hemorrhage is recommended to prevent recurrent hemorrhage. The risk of craniotomy and resection of BAVM has been well described using the Spetzler-Martin grading scale; however, the optimal timing for the definitive treatment of ruptured BAVM remains unclear. We report an interesting case of spontaneous BAVM thrombosis in which the patient presented with right occipital intracerebral hemorrhage caused by ruptured right occipital micro-BAVM. A preoperative angiogram 4 months later demonstrated spontaneous thrombosis of the AVM. Despite the risk of re-bleeding, the decision to defer treatment in the acute stage of illness in this case was based on the absence of high-risk angioarchitectural features in the arteriovenous malformations (AVM). It is important to emphasize the potential benefits of early conservative management, particularly in patients with low-risk angiographic features. We also review the literature of spontaneous BAVM thrombosis and discuss the potential benefit of early conservative management.

The clinical characteristics and treatment of cerebral AVM in pregnancy

Cerebral arteriovenous malformation (AVM) in pregnancy is a complex situation and there is no agreement on its hemorrhage risk and treatment. Although studies on bleeding risk of cerebral AVMs in pregnancy are very few and there are different results between them, pregnancy will increase the hemorrhagic risk of AVM, and ruptured cerebral AVM in pregnancy should be treated actively. After intracranial hemorrhage, cerebral angiography should be performed for pregnant women shielded correctly. Cerebral angiography could clearly demonstrate the characteristics of cerebral AVM. The results from the literature show that the radiation dose of endovascular and stereotactic radiotherapy for cerebral AVM in pregnancy is below the safety value and is safe. Unruptured AVM in pregnancy, if there is no bleeding factor, such as no coexisting aneurysm, smooth venous drainage, no venous ectasia, or high risk of treatment, should be observed conservatively.

The clinical characteristics and treatment of cerebral AVM in pregnancy

Cerebral arteriovenous malformation (AVM) in pregnancy is a complex situation and there is no agreement on its hemorrhage risk and treatment. Although studies on bleeding risk of cerebral AVMs in pregnancy are very few, and they provide different results, pregnancy will increase the hemorrhagic risk of AVM and ruptured cerebral AVM in pregnancy should be actively treated. After intracranial hemorrhage, cerebral angiography should be performed for pregnant women shielded correctly. Cerebral angiography could clearly demonstrate the characteristics of cerebral AVM. Results from the literature show that the radiation dose of endovascular and stereotactic radiotherapy for cerebral AVM in pregnancy was below the safety value and was safe. For an unruptured AVM in pregnancy, if there are no bleeding factors, e.g. no coexisting aneurysm, smooth venous drainage, no venous ectasia, or high risk of treatment, then it should be observed conservatively.

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

BACKGROUND AND PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Critical assessment of the morbidity associated with ruptured cerebral arteriovenous malformations

BACKGROUND

An accurate understanding of the morbidity and mortality associated with brain arteriovenous malformation (AVM) hemorrhage is important in determining the management of unruptured AVMs. Recent studies suggest this morbidity to be lower than assumed. We sought to perform a detailed critical assessment of the morbidity associated with ruptured brain AVMs.

METHODS

A retrospective chart review from a single-center tertiary care medical center was performed. Inclusion criteria were patients admitted with intracranial hemorrhage caused by a previously untreated AVM. Forty variables were analyzed including patient demographics, imaging findings, clinical course, and clinical examinations.

RESULTS

From 2008 to 2013, of the 51 patients who fit our inclusion criteria, we found admission National Institutes of Health Stroke Scale (NIHSS) scores of 0, 1-9, and ≥10 in 22%, 24%, and 55%, respectively. Hematoma location was parenchymal in 33%, intraventricular in 10%, subarachnoid in 4%, and combined in 53%. Deep venous drainage was present in 35% of cases and associated aneurysms were present in 37%. 43% underwent emergency hematoma evacuation while four patients died during their admission. Of those who survived, 74% had neurologic deficits upon discharge (NIHSS ≥1), with 25.5% of patients having a severe deficit (NIHSS ≥10). On follow-up, 55% were independent in their daily activities of living.

CONCLUSIONS

Our assessment of morbidity associated with brain AVM rupture is higher than previously assumed and reported. These results should be further validated in a larger, more representative sample. An accurate understanding of the morbidity associated with AVM rupture is important as more patients with unruptured brain AVMs seek consultation.

Number and location of draining veins in pediatric arteriovenous malformations: association with hemorrhage

OBJECT

The significance of draining vein anatomy is poorly defined in pediatric arteriovenous malformations (AVMs). In adult cohorts, the presence of fewer veins has been shown to lead to an increased rate of hemorrhage, but this phenomenon has not yet been studied in pediatric AVMs. This report analyzes the impact of draining vein anatomy on presentation and outcome in a large series of pediatric AVMs.

METHODS

Eighty-five pediatric patients with AVMs were treated at the Columbia University Medical Center between 1991 and 2012. Charts were retrospectively reviewed for patient characteristics, clinical course, neurological outcome, and AVM angioarchitectural features identified on the angiogram performed at presentation. Univariate analyses were performed using chi-square test and ANOVA when appropriate; multivariate analysis was performed using logistic regression.

RESULTS

Four patients were excluded due to incomplete records. Twenty-seven patients had 2 or 3 draining veins; 12 (44.4%) of these patients suffered from hemorrhage prior to surgery. Fifty-four patients had 1 draining vein; 39 (72.2%) of these 54 suffered from hemorrhage. Independent predictors of hemorrhage included the presence of a single draining vein (p = 0.04) and deep venous drainage (p = 0.02). Good outcome (modified Rankin Scale [mRS] score < 3) on discharge was found to be associated with higher admission Glasgow Coma Scale (GCS) scores (p = 0.0001, OR 0.638, 95% CI 0.40-0.93). Poor outcome (mRS score > 2) on discharge was found to be associated with deep venous drainage (p = 0.04, OR 4.68, 95% CI 1.1-19.98). A higher admission GCS score was associated with a lower discharge mRS score (p = 0.0003, OR 0.6, 95% CI 0.46-0.79), and the presence of a single draining vein was associated with a lower mRS score on long-term follow-up (p = 0.04, OR 0.18, 95% CI 0.032-0.99).

CONCLUSIONS

The authors' data suggest that the presence of a single draining vein or deep venous drainage plays a role in hemorrhage risk and ultimate outcome in pediatric AVMs. Small AVMs with a single or deep draining vein may have the highest risk of hemorrhage.