Exclusive Deep Venous Drainage Research Articles

Neural Network Helps Determine the Hemorrhagic Risk of Cerebral Arteriovenous Malformation

We aimed to determine whether the hemorrhage risks of cerebral arteriovenous malformation (AVM), evaluated through digital subtraction angiography (DSA) using a neural network, were superior to those assessed through angioarchitecture. We conducted a retrospective review of patients with cerebral AVM who underwent DSA from 2011 to 2017. Angioarchitecture parameters, age, and sex were analyzed using univariate and multivariate logistic regression. Additionally, a neural network was trained using a combination of convolutional neural network (CNN) and recurrent neural network (RNN) architectures. The training dataset consisted of 118 samples, while 29 samples were reserved for testing. After adjusting for age at diagnosis and sex, single venous drainage (odds ratio [OR] = 2.48, p = 0.017), exclusive deep venous drainage (OR = 3.19, p = 0.005), and venous sac (OR = 0.43, p = 0.044) were identified as independent risk factors for hemorrhage. The angioarchitecture-based hemorrhagic prediction model achieved 69% accuracy with an AUC (area under the ROC curve) of 0.757, while the CNN–RNN-based model achieved 76% accuracy with an AUC of 0.748. We present a diagnostic performance for hemorrhagic risk assessment of AVMs that is comparable to the angioarchitectural analysis. By leveraging larger datasets, there is significant potential to enhance prediction accuracy further. The CNN–RNN algorithm not only can potentially streamline workflow within the angio-suite but also serves as a complementary approach to optimize diagnostic accuracy and treatment strategies.

Angiographic factors leading to hemorrhage in AVMs: A systematic review and meta-analysis.

For patients with unruptured intracranial arteriovenous malformations (AVMs), the risk of a hemorrhagic event is approximately 2% to 4% annually. These events have an associated 20-50% morbidity and 10% mortality rate. An understanding of risk factors that predispose these lesions to rupture is important for optimal management. We aimed to pool a large cohort of both ruptured and unruptured AVMs from the literature with the goal of identifying angiographic risk factors that contribute to rupture. A systematic review of the literature was conducted in accordance with the PRISMA guidelines using Pubmed, Embase, Scopus, and Web of Science databases. Studies that presented patient-level data from ruptured AVMs from January 1990 to January 2022 were considered for inclusion. The initial screening of 8,304 papers resulted in a quantitative analysis of 25 papers, which identified six angiographic risk factors for AVM rupture. Characteristics that significantly increase the odds of rupture include the presence of aneurysm (OR = 1.45 [1.19, 1.77], p < 0.001, deep location (OR = 3.08 [2.56, 3.70], p < 0.001), infratentorial location (OR = 2.79 [2.08, 3.75], p < 0.001), exclusive deep venous drainage (OR = 2.50 [1.73, 3.61], p < 0.001), single venous drainage (OR = 2.97 [1.93, 4.56], p < 0.001), and nidus size less than 3cm (OR = 2.54 [1.41, 4.57], p = 0.002). Although previous literature has provided insight into AVM rupture risk factors, obscurity still exists regarding which risk factors pose the greatest risk. We have identified six major angiographic risk factors (presence of an aneurysm, deep location, infratentorial location, exclusive deep venous drainage, single venous drainage, and nidus size less than 3cm) that, when identified by a clinician, may help to tailor patient-specific approaches and guide clinical decisions.

External validation of the R2eD AVM scoring system to assess rupture risk in pediatric AVM patients.

The assessment of hemorrhagic risk is of central importance in the management of pediatric brain arteriovenous malformations (AVMs). A recently published scoring system, the R2eD AVM (race, exclusive deep location or not, AVM size < 3 or ≥ 3, venous drainage exclusively deep or not, and monoarterial feeding or >1 arterial feeders) considers patient race and AVM location, size, venous drainage, and arterial supply and was successfully externally validated for use in adults to predict the risk of AVM hemorrhagic presentation. In this study the authors sought to externally validate the R2eD AVM score for prediction of hemorrhagic risk in the pediatric AVM population. A pediatric database at Boston Children's Hospital was retrospectively reviewed for all patients with a diagnosis of intracranial AVM. Exclusion criteria included age > 21 years, multiple AVMs, and incomplete clinical/radiographic data. Demographic data and R2eD AVM score calculations were collected for all patients. Univariate binary logistic regression and multivariate stepwise backward elimination models were used to determine factors associated with hemorrhagic presentation. A total of 212 AVMs were identified in 212 patients with vascular anomalies from 1995 to 2021, and 144 patients met the inclusion criteria (74 [51.4%] male, 111 [77.1%] White), of whom 87 (60.4%) patients presented with rupture and 122 (84.7%) underwent resection. The mean age at surgery was 12 years (range 3 months to 20 years). The R2eD AVM scoring system was applied to each patient. The score components of size < 3 cm and exclusive deep venous drainage were significantly associated with rupture risk (p < 0.05). The complete model for the R2eD AVM score had an area under the curve of 0.671 (95% CI 0.586-0.757). This study demonstrated poor external validity of the R2eD AVM score in predicting pediatric AVM rupture risk. The results suggest that future studies are warranted to determine a better scoring method to capture pediatric rupture risk, given the significant differences in clinical presentation in pediatric compared with adult AVM patients.

A Rational Approach to the Management of Cerebral Arteriovenous Malformations

Cerebral arteriovenous malformations (AVMs) typify the delicate balance cerebrovascular specialists face in weighing the treatment risk against the natural history of a pathologic lesion. The goal of our review was to provide an overview of the current evidence for the treatment of cerebral AVMs and describe a contemporary approach to developing a treatment strategy according to individual AVM characteristics. A review of the contemporary literature on the natural history and treatment of cerebral AVMs was completed through the PubMed and Google Scholar databases. The studies were reviewed for original advances in the characterization and treatment of cerebral AVMs. The overall risk of hemorrhage for cerebral AVMs is 2%-4% per year. Individual AVM characteristics, including small size, exclusive deep venous drainage, deep or posterior fossa location, venous ectasia, and the presence of a flow-associated aneurysm, appear to confer a greater risk of presentation with rupture. A diverse array of modalities have been developed to achieve the goal of complete lesion obliteration, including microsurgery, endovascular therapy, and radiosurgery. Advances in treatment strategies and technology have continued to decrease the morbidity associated with lesion obliteration. Microsurgical or multimodal treatment strategies are often required to achieve complete obliteration; however, it remains critical that each treatment approach is individualized by the specific AVM characteristics.

External Validation of the R2eD AVM Score to Predict the Likelihood of Rupture Presentation of Brain Arteriovenous Malformations

The R2eD AVM scoring system has been recently proposed to predict the risk of hemorrhagic presentation of brain arteriovenous malformations (AVMs). To perform the first external validation of this R2eD AVM score. Over a retrospective 10-yr period from 2009 to 2019, 122 patients with brain AVMs fit the inclusion criteria. All components required to calculate the R2eD AVM score had to be available. Patient demographics and score calculations were recorded, as well as the circumstances of their presentation. Multivariable analysis was performed to assess predictors of rupture in the study cohort. Next, area under the receiver operating characteristics and linear-by-linear association were employed to assess the effectiveness of the models. The mean age of the entire cohort was 45.2 yr, and 8% of patients were nonwhite. A total of 48 (39.3%) patients presented with AVM rupture. In univariable analysis, all 5 categories demonstrated P <.15 association with rupture risk. In multivariable analysis, race (nonwhite), size <3cm, and exclusive deep venous drainage remained in the model with an area under the curve (AUC) of 0.677. The utilization of the R2eD AVM score yielded an AUC of 0.711. Even though mitigated by sample size, this study demonstrated acceptable external validity of the R2eD AVM score.

Stagnant venous outflow in ruptured arteriovenous malformations revealed by delayed quantitative digital subtraction angiography

PurposeTo investigate the reproducibility of quantitative digital subtraction angiography (QDSA) measurements and their associations with brain arteriovenous malformation (BAVM) hemorrhage. MethodsFrom 2011–2019, 37 patients with BAVMs who had undergone both diagnostic and stereotactic DSA were divided into hemorrhagic and nonhemorrhagic groups. QDSA analysis was performed on the 2 DSA exams. The inter-exam reliabilities of QDSA measurements across the diagnostic and stereotactic DSA were tested using intraclass correlation coefficients (ICCs). Demographics, BAVM characteristics, and QDSA results for the hemorrhagic and nonhemorrhagic groups were compared. ResultsFifteen of 37 (40.5 %) patients presented with hemorrhage were associated with smaller BAVM volume and the presence of intranidal aneurysm and exclusive deep venous drainage. The median interval between the diagnostic and stereotactic DSA was 49 days and did not differ between the groups. In both groups, the inter-exam QDSA measurements were more reliable for drainage veins and transnidal time (ICCs ranged from 0.38–0.93) than for feeding arteries (ICCs ranged from 0.01–0.74). Among the venous parameters, the hemorrhagic group had lower peak density, area under the curve, inflow gradient, and outflow gradient on both DSA exams and larger full width at half maximum and stasis index on the stereotactic DSA exam than the nonhemorrhagic group. ConclusionsIn BAVMs, the QDSA measurements for veins are more reliable than those for arteries. QDSA analysis reflecting stagnant venous drainage is associated with BAVM hemorrhage, but may be confounded by the acute hemodynamic change after hemorrhage.

The R2eD Arteriovenous Malformation Score: A Novel Predictive Tool for Arteriovenous Malformation Presentation With Hemorrhage

Abstract INTRODUCTION The management of unruptured brain arteriovenous malformations (AVMs) remains unclear. This study aims to develop a predictive tool that could guide hemorrhage risk stratification. METHODS A database of 789 AVM patients presenting to our institution between 1990 and 2017 was used. A hold-out method of model building and validation was employed whereby the data was randomly split in half into training and validation datasets. Factors significantly associated with hemorrhage presentation at the univariable level in the training dataset were used to construct a model based on multivariable logistic regression. Model performance was assessed using receiver operating curves (ROC) on the training, validation, and complete datasets. The model predictors and the complete dataset were then used to derive a formula for risk prediction and a practical scoring system according to the model coefficients. RESULTS In 755 patients with complete data on presentation status, 272 (36%) presented with hemorrhage. After model building and validation, the final model contained the following risk factors: non-white race (odds ratio [OR] = 2.49, P &lt; .01), deep location (OR = 1.68, P = .02), small AVM size (&lt;3 cm, OR = 1.63, P &lt; .01), exclusive deep venous drainage (OR = 1.73, P = .02), and “monoarterial” feeding (OR = 1.58, P = .02). Area under the curve from ROC analysis was 0.702, 0.698, and 0.685 for the training, validation, and complete datasets, respectively. Every risk factor was worth 1 point except race, which was worth 2 points. The factors are summarized by the acronym R2eD AVM (total score varies from 0 to 6). 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) with around a 10% increase in risk per added point. CONCLUSION This risk can be used as a predictive tool that supplements clinical judgement and aids in patient counselling.

Stasis index from hemodynamic analysis using quantitative DSA correlates with hemorrhage of supratentorial arteriovenous malformation: a cross-sectional study.

Assessments of hemorrhage risk based on angioarchitecture have yielded inconsistent results, and quantitative hemodynamic studies have been limited to small numbers of patients. The authors examined whether cerebral hemodynamic analysis using quantitative digital subtraction angiography (QDSA) can outperform conventional DSA angioarchitecture analysis in evaluating the risk of hemorrhage associated with supratentorial arteriovenous malformations (AVMs). A cross-sectional study was performed by retrospectively reviewing adult supratentorial AVM patients who had undergone both DSA and MRI studies between 2011 and 2017. Angioarchitecture characteristics, DSA parameters, age, sex, and nidus volume were analyzed using univariate and multivariate logistic regression, and QDSA software analysis was performed on DSA images. Based on the QDSA analysis, a stasis index, defined as the inflow gradient divided by the absolute value of the outflow gradient, was determined. The receiver operating characteristic (ROC) curve was used to compare diagnostic performances of conventional DSA angioarchitecture analysis and analysis using hemodynamic parameters based on QDSA. A total of 119 supratentorial AVM patients were included. After adjustment for age at diagnosis, sex, and nidus volume, the exclusive deep venous drainage (p < 0.01), observed through conventional angioarchitecture examination using DSA, and the stasis index of the most dominant drainage vein (p = 0.02), measured with QDSA hemodynamic analysis, were independent risk factors for hemorrhage. The areas under the ROC curves for the conventional DSA method (0.75) and QDSA hemodynamics analysis (0.73) were similar. A venous stasis index greater than 2.18 discriminated the hemorrhage group with a sensitivity of 52.6% and a specificity of 81.5%. In QDSA, a higher stasis index of the most dominant drainage vein is an objective warning sign associated with supratentorial AVM rupture. Risk assessments of AVMs using QDSA and conventional DSA angioarchitecture were equivalent. Because QDSA is a complementary noninvasive approach without extra radiation or contrast media, comprehensive hemorrhagic risk assessment of cerebral AVMs should include both DSA angioarchitecture and QDSA analyses.

Relationship of pulsatility and resistance indices to cerebral arteriovenous malformation angioarchitectural features and hemorrhage

The role that hemodynamics plays in the pathophysiology of cerebral arteriovenous malformation (AVM) hemorrhage remains unclear. Here, we examine the relationship of pulsatility and resistance indices to AVM angioarchitectural features and hemorrhage. Records of patients with cerebral AVMs evaluated at our institution between 2007–2014 and with flows obtained before treatment using quantitative magnetic resonance angiography (QMRA) were retrospectively reviewed. Flow volume rate and flow velocity were measured in primary arterial feeders and compared to their contralateral counterparts. Pulsatility index (PI)=[(systolic flow velocity−diastolic flow velocity)/mean flow velocity] and resistance index (RI)=[(systolic flow velocity−diastolic flow velocity)/systolic flow velocity] were calculated for each feeder and compared to the normal contralateral vessel. Relationships between PI, RI and AVM clinical and angioarchitectural features were assessed using linear regression. Seventy-two patients with a total of 101 feeder arteries were included. PI and RI were significantly lower in AVM arterial feeders compared to normal vessels, thereby resulting in significantly higher flow volume rates and flow velocities in feeder vessels. There was no significant association of PI and RI with hemorrhagic presentation, exclusive deep venous drainage, venous stenosis, single draining vein, or deep location. In conclusion, PI and RI can be measured using QMRA and are lower in AVM arterial feeders compared to normal vessels. Although we found no significant correlation between PI, RI, and AVM angioarchitectural characteristics thought to be associated with increased hemorrhage risk, future studies with larger sample sizes may better elucidate this relationship.

Angioarchitectural Risk Factors for Hemorrhage and Clinical Long-Term Outcome in Pediatric Patients with Cerebral Arteriovenous Malformations

Intracranial arteriovenous malformation (AVM) in children is a rare diagnosis. Little is known about factors determining AVM rupture and appropriate treatment strategies to prevent hemorrhage and associated disability. Available data suggest that children are subject to an increased risk for AVM rupture compared with adults. In 46 pediatric patients with AVM, demographic factors, clinical presentation, angioarchitectural features, and treatment regimens as well as clinical and radiologic outcomes were retrospectively analyzed. First-line treatment option was microsurgical resection of the disease, with or without preoperative embolization. Twenty-four boys (52.2%) and 22 girls (47.8%) with a mean age on admission of 12.4 years (4-18 years) were included. Mean follow-up was 4 years (median, 1.5; range, 0.1-16.4). Thirty-one children presented with intracerebral hemorrhage (67.4%). Small AVMs (<3 cm) ruptured in 83.3% (n= 25) and were shown to be more prone to hemorrhage than larger ones (P < 0.01). Small AVM size (P< 0.01; odds ratio [OR], 0.12; 95% confidence interval [CI] 0.02-0.59) and exclusive deep venous drainage (P < 0.01; OR, 29.74; 95% CI, 2.45-4445.34) were independent risk factors for hemorrhage in the presented cohort. Good long-term outcome was associated with a high score on the Glasgow Coma Scale on admittance (P < 0.05; OR, 0.148; 95% CI, 0.03-0.73). Two-thirds of children with AVM are admitted with intracerebral hemorrhage. Microsurgical resection was successful as confirmed by radiologic studies in 95%, and 79.5% of patients presented in a good clinical condition on follow-up (modified Rankin Scale 0 or1). Microsurgical treatment is recommended if the lesion is accessible and angioarchitectural risk factors favor definitive treatment.

E-099 evaluation of pulsatility and resistance indices in arterial feeders of cerebral arteriovenous malformations using quantitative magnetic resonance angiography

Introduction/purpose The characterization of cerebral arteriovenous malformation (AVM) hemodynamics is important in the evaluation and management of AVMs. Here, we measure flow volume rate, flow velocity, pulsatility index (PI), and resistance index (RI) in arterial feeders of AVMs using quantitative magnetic resonance angiography (QMRA). Materials and methods Records of patients with cerebral AVMs evaluated at our institution between 2007–2014 and with flows obtained before treatment using QMRA were retrospectively reviewed. Flow volume rate and flow velocity were measured in primary arterial feeders (anterior cerebral artery, A2 segment; middle cerebral artery, M1 segment; posterior cerebral artery, P2 segment) and compared to their contralateral counterparts. PI = [(systolic - diastolic flow velocity)/mean flow velocity] and RI = [(systolic - diastolic flow velocity)/systolic flow velocity] were calculated for each feeder and compared to the normal contralateral vessel. The relationship between PI, RI and AVM clinical and angioarchitectural features was also assessed. Results 72 patients with a total of 98 feeder arteries were included. Cohort characteristics are summarized in Table 1. Among all feeders, mean flow volume rate (332.3 vs. 121.6 mL/min, P P P P .001) were significantly lower than in the normal contralateral vessels (Figure 1). Similar results were obtained among each feeder vessel type. There was no significant association of feeder vessel PI and RI with hemorrhagic presentation ( P = 0 .64,0.80, respectively), exclusive deep venous drainage ( P = 0 .75,0.11), venous stenosis ( P = 0 .42,0.70), single draining vein ( P = 0 .91, 0.90), or deep location ( P = 0 .32,0.78). Conclusion PI and RI can be measured using QMRA and are significantly lower in AVM arterial feeders compared to normal vessels, thereby resulting in significantly higher flow volume rates and flow velocities in feeder vessels. Although we found no significant correlation between PI, RI, and AVM angioarchitectural characteristics thought to be associated with increased hemorrhage risk, future studies with larger sample sizes may better elucidate this relationship. Disclosures S. Shakur: None. S. Amin-Hanjani: None. H. Mostafa: None. V. Aletich: None. F. Charbel: None. A. Alaraj: None.

125 Vein Number and Drainage Pattern Predicts Hemorrhage Risk and Outcome in Pediatric Arteriovenous Malformations

INTRODUCTION: The significance of draining vein anatomy is poorly defined in pediatric arteriovenous malformations. In adult cohorts, venous characteristics have been shown to lead to an increased rate of hemorrhage, but this phenomenon has not been well 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-one 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, outcome, and AVM angioarchitectural features. Univariate analyses were performed and multivariate analysis was performed using logistic regression for variables with P < .2. RESULTS: Twenty-seven patients had 2 or 3 draining veins and 20 patients presented with exclusive deep venous drainage. Patients presenting with 2 or greater draining veins were less likely to present with hemorrhage than patients with a single draining vein (OR: 5.16; P = .044). Patients with exclusively deep drainage were more likely to present with hemorrhage (OR: 8.22; P = .024). Patients with a single draining vein were less likely to have impairments causing disability (OR: 0.18; P = .049) on long term follow up, but not on discharge (P = .1). Exclusively deep drainage was found to predict discharge outcome (OR: 4.68; P = .04) but not long term outcome (P = .3). CONCLUSION: This study suggests that the influence of draining veins in pediatric arteriovenous malformations is significant. A single draining vein or an exclusively deep drainage system seems to increase a patient's risk of hemorrhage. This effect could potentially be due to an increased degree of venous impedance. The short term effect on outcome due to drainage pattern may be due to increased surgical morbidity, whereas a negative effect on long term outcome when multiple veins were present may be due to a greater disruption of the cerebral venous drainage patterns.

Angioarchitectural Characteristics Associated with Complications of Embolization in Supratentorial Brain Arteriovenous Malformation

Embolization is an important therapeutic technique in brain arteriovenous malformations; however, little has been reported on the factors contributing to complications. We retrospectively reviewed a large series of supratentorial brain AVMs to identify the angioarchitectural characteristics that might be associated with the complications of embolization and poor clinical outcomes. The clinical and angiographic features of 130 consecutive patients with supratentorial brain AVMs embolized with ethylene-vinyl alcohol copolymer in our hospital from 2005-2008 were retrospectively reviewed. None of these patients had prior embolization. Complications were classified as transient neurologic deficits, persistent neurologic deficits, and death. Univariate and multivariate analyses were conducted to assess the angiographic features in patients with and without complications. Twenty-three complications occurred in 130 embolization procedures, 13 (10%) were transient neurologic deficits (9 ischemic and 4 hemorrhagic), 9 (6.92%) were persistent neurologic deficits (7 ischemic and 2 hemorrhagic), and 1 death occurred. By univariate analyses, eloquent cortex (OR, 2.57; 95% CI, 1.08-3.42) and exclusive deep venous drainage (OR, 4.56; 95% CI, 1.28-9.67) were correlated with procedural complications. The impaction of eloquent cortical location (P = .001) and exclusive deep venous drainage (P = .035) on complications were also demonstrated by multivariate analysis. Eloquent cortex mainly resulted in permanent ischemic neurologic deficit; occlusion of drainage vein was significantly correlated with periprocedural hemorrhage in supratentorial brain AVMs with subtotal and partial embolization. In a retrospective study on supratentorial brain AVMs with first-time embolization, 6.92% of patients had permanent neurologic deficit or death. Eloquent cortical location and exclusive deep venous drainage were associated with complications.

Angioarchitectural characteristics associated with initial hemorrhagic presentation in supratentorial brain arteriovenous malformations

ObjectiveThe difference in arterial supply, venous drainage, functional localization in supratentorial and infratentorial compartments may contribute to the conflicting results about risk factors for hemorrhage in published case series of brain arteriovenous malformation (bAVM). Further investigation focused on an individual brain compartment is thus necessary. This retrospective study aims to identify angioarchitectural characteristics associated with the initial hemorrhagic event of supratentorial bAVMs. Materials and methodsThe clinical and angiographic features of 152 consecutive patients with supratentorial bAVMs who presented to our hospital from 2005 to 2008 were retrospectively reviewed. All these patients had new diagnosis of bAVM. Univariate (χ2 test) and multivariate analyses were conducted to assess the angiographic features in patients with and without initial hemorrhagic presentations. A probability value of less than 0.05 was considered statistically significant in each analysis. ResultsIn 152 patients with supratentorial AVMs, 70.6% of deep and 52.5% of superficial sbAVMs presented with hemorrhage. The deep location was correlated with initial hemorrhagic presentation in univariate analysis (χ2=3.499, p=0.046) but not in the multivariate model (p=0.144). There were 44 sbAVMs with perforating feeders, 39 (88.6%) of which bled at a significantly higher rate than those with terminal feeders (χ2=25.904, p=0.000). 87.5% (21/24) of exclusive deep venous drainage presented with hemorrhage, a significantly higher rate than those of the other type of venous drainage (χ2=11.099, p=0.004). All 10 patients with both perforating feeders and exclusive deep draining vein presented with initial hemorrhage. Hemorrhagic presentation was correlated with perforating feeders (p=0.000) and exclusive deep draining vein (p=0.007) in multivariate analysis as well. ConclusionsSupratentorial bAVMs with perforating feeders and deep venous drainage have a higher risk of hemorrhage. In contrast with many previous reports, AVM location was not associated with hemorrhagic presentation in adjusted analyses. The correlation between deep location and initial hemorrhage in univariate analysis might be caused by the involved perforating feeders and deep draining vein in the deep located AVMs.

Intranidal Signal Distribution in Post-Contrast Time-of-Flight MRA is Associated with Rupture Risk Factors in Arteriovenous Malformations

To evaluate if arteriovenous malformations (AVMs) that are associated with a high rupture risk (HRR) are represented by different intranidal Time-of-Flight (TOF) magnetic resonance angiography intensity distributions compared to those with presumably low rupture risk (LRR). Fifty post-contrast TOF datasets of patients with an AVM were analyzed in this study. The patients were classified to the HRR group in case of a deep location, presence of exclusive deep venous drainage, previous hemorrhagic event or a combination thereof. For each TOF dataset, the AVM nidus was semi-automatically delineated and used for histogram extraction. Each histogram was analyzed by calculating the skewness, kurtosis, mean and median intensity and full-width-half-maximum. Statistical analysis was performed using parameter-wise two-sided t-tests of the parameters between the two groups. Based on morphological analysis, 21 patients were classified to the HRR and 29 patients to the LRR group. Statistical analysis revealed that TOF intensity distributions of HRR AVMs exhibit a significant higher skewness (p=0.0005) parameter compared to LRR AVMs. Contrary to these findings, no significant differences were found for the other parameters evaluated. Intranidal flow heterogeneity, for example, caused by turbulent flow conditions, may play an important role for risk of a hemorrhage. An analysis of post-contrast TOF intensities within the nidus of an AVM may offer simple and valuable information for clinical risk estimation of AVMs and needs to be tested prospectively.

Angioarchitectural features associated with hemorrhagic presentation in pediatric cerebral arteriovenous malformations

Background and objectiveTo date, there have been few published studies examining the relationship between arteriovenous malformation (AVM) angioarchitecture and hemorrhagic presentation among children with cerebral AVMs. This study examines this...

NS17 SURGERY REMAINS THE TREATMENT OF CHOICE FOR AVMS?

The reported annual risk of haemorrhage for conservatively managed AVMs varies from less than 1% to more than 33% depending on the combination of the presence or absence of some of the following variables: haemorrhagic presentation, presence of aneurysms, the presence of exclusive deep venous drainage, and a deep location was deep. Over time, the acquisition of wear‐and‐tear associated pathologies increases the risk of haemorrhage for those that initially present with a low haemorrhage risk. It is likely that the long‐term risk is in excess of 50% over 20 years. The combined morbidity and mortality from haemorrhage is 50%.Once an AVM has been diagnosed there are four treatment options to be considered to eliminate the risk of haemorrhage. Surgery, focussed irradiation, embolisation or a combination of treatments. Consideration needs to be given to both the likelihood of haemorrhage risk elimination and the time to achieving this goal and morbidity of the procedure.Surgery for Spezler Martin grades less than 3 have close to 100% likelihood of cure and a risk of treatment morbidity less than 5% of surgery for the vast majority of cases. This result is unlikely to be approached by other modalities. For grades above 2 AVMs when the nidus is less than 3 cm, without feeding artery aneurysms or recent haemorrhage and has lenticulostriate supply, focussed irradiation is likely to be the treatment of choice. But for all other AVMs surgery remains the only reliable curative option. Combination treatments are ineffective in reducing the risks except when embolisation precedes surgery.

Predictors of hemorrhage in patients with untreated brain arteriovenous malformation

Background: Intracranial hemorrhage is a serious possible complication in patients with brain arteriovenous malformation (AVM). Several morphologic factors associated with hemorrhagic AVM presentation have been established, but their relevance for the risk of subsequent AVM hemorrhage remains unclear. Methods: The authors analyzed follow-up data on 622 consecutive patients from the prospective Columbia AVM database, limited to the period between initial AVM diagnosis and the start of treatment (i.e., any endovascular, surgical, or radiation therapy). Univariate and multivariate logistic regression and Cox proportional hazard models were applied to analyze the effect of patient age, gender, AVM size, anatomic location, venous drainage pattern, and associated arterial aneurysms on the risk of intracranial hemorrhage at initial presentation and during follow-up. Results: The mean pretreatment follow-up was 829 days (median: 102 days), during which 39 (6%) patients experienced AVM hemorrhage. Increasing age (hazard ratio [HR] 1.05, 95% CI 1.03 to 1.08), initial hemorrhagic AVM presentation (HR 5.38, 95% CI 2.64 to 10.96), deep brain location (HR 3.25, 95% CI 1.30 to 8.16), and exclusive deep venous drainage (HR 3.25, 95% CI 1.01 to 5.67) were independent predictors of subsequent hemorrhage. Annual hemorrhage rates on follow-up ranged from 0.9% for patients without hemorrhagic AVM presentation, deep AVM location, or deep venous drainage to as high as 34.4% for those harboring all three risk factors. Conclusions: Hemorrhagic arteriovenous malformation (AVM) presentation, increasing age, deep brain location, and exclusive deep venous drainage appear to be independent predictors for AVM hemorrhage during natural history follow-up. The risk of spontaneous hemorrhage may be low in AVMs without these risk factors.

Predictors of hemorrhage in patients with untreated brain arteriovenous malformation

Intracranial hemorrhage is a serious possible complication in patients with brain arteriovenous malformation (AVM). Several morphologic factors associated with hemorrhagic AVM presentation have been established, but their relevance for the risk of subsequent AVM hemorrhage remains unclear. The authors analyzed follow-up data on 622 consecutive patients from the prospective Columbia AVM database, limited to the period between initial AVM diagnosis and the start of treatment (i.e., any endovascular, surgical, or radiation therapy). Univariate and multivariate logistic regression and Cox proportional hazard models were applied to analyze the effect of patient age, gender, AVM size, anatomic location, venous drainage pattern, and associated arterial aneurysms on the risk of intracranial hemorrhage at initial presentation and during follow-up. The mean pretreatment follow-up was 829 days (median: 102 days), during which 39 (6%) patients experienced AVM hemorrhage. Increasing age (hazard ratio [HR] 1.05, 95% CI 1.03 to 1.08), initial hemorrhagic AVM presentation (HR 5.38, 95% CI 2.64 to 10.96), deep brain location (HR 3.25, 95% CI 1.30 to 8.16), and exclusive deep venous drainage (HR 3.25, 95% CI 1.01 to 5.67) were independent predictors of subsequent hemorrhage. Annual hemorrhage rates on follow-up ranged from 0.9% for patients without hemorrhagic AVM presentation, deep AVM location, or deep venous drainage to as high as 34.4% for those harboring all three risk factors. Hemorrhagic arteriovenous malformation (AVM) presentation, increasing age, deep brain location, and exclusive deep venous drainage appear to be independent predictors for AVM hemorrhage during natural history follow-up. The risk of spontaneous hemorrhage may be low in AVMs without these risk factors.