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Our results conflict with those from a recent study describing no increased rate of rupture during pregnancy. This difference may reflect unique population attributes influencing brain AVM hemorrhage during pregnancy.

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.

S-HGGs are rare tumors with aggressive course of disease. We have found that overall median survival of S-HGGs is poor at 24 months, and no demographic or tumor-related factors have been confirmed. Extend of surgery is not associated with improved survival after adjusting for postoperative RT. Postoperative RT is the only factor in our study associated with prolonged survival in S-HGGs.

BACKGROUND Spontaneous obliteration (SpO) of untreated arteriovenous malformations (AVMs) is rare with fewer than 100 cases reported. The incidence and predisposing factors of SpO remain unclear, impeding our understanding of lesion progression in untreated patients. OBJECTIVE To determine the incidence rate and predisposing factors of SpO in a North American cohort. METHODS AVMs were retrospectively evaluated at our institution for over 25 yr. Untreated AVMs were divided into 2 groups: SpO-AVMs and non-SpO-AVMs. All statistical results were based on univariate analyses. Incidence was generated from counts of SpO over the untreated interval in patient years from birth until obliteration, treatment, or last follow-up. RESULTS One hundred fifty-four patients had untreated AVMs; SpO was observed in 4. Average ages were 49.0 ± 23.6 and 48.7 ± 20.4 yr in the SpO-AVM and non-SpO-AVM group, respectively (P = .98). Average AVM sizes were 2.0 ± 1.8 cm (SpO-AVMs) and 3.7 ± 2.6 cm (non-SpO-AVMs, P = .25). All SpO-AVMs and 40 (27.0%) non-SpO-AVMs had a ruptured presentation (P = .006). A single draining vein was observed in all SpO-AVMs and 39 (32.8%) non-SpO-AVMs (P = .01). Deep venous drainage was not observed in any SpO-AVMs, but in 81 (57.9%) non-SpO-AVMs (P = .04). Mean follow-up time was 37.0 ± 42.6 and 75.6 ± 161.7 mo in SpO-AVM and non-SpO-AVMs patients, respectively. Of the 2 SpO-AVM patients with postobliteration follow-up, 1 experienced recanalization. From a 672-patient cohort, the incidence of SpO over 28 961 patient years was 0.014%. CONCLUSION SpO-AVMs have an annual incidence rate of approximately 0.014% and tend to present with rupture, a single draining vein, and superficial venous drainage. Expectation of SpO for untreated AVMs is not justified, and patients should anticipate life-long hemorrhagic risk for untreated AVMs.

Subtypes of grade II AVMs portend different posttreatment gains in functional outcome. Group 1 (S2V0E0) patients had the best functional outcome gain from treatment, while group 3 (S1V1E0) patients fared less well, particularly with surgical treatment.

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 < .01), deep location (OR = 1.68, P = .02), small AVM size (<3 cm, OR = 1.63, P < .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.