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Objective: The longitudinal management of unruptured brain arteriovenous malformation (bAVM) is crucial. To date, no study in the United States has evaluated the impact of socioeconomic status (SES) on bAVM outcome. Herein, the authors aimed to clarify the impact of SES, as indicated by the area deprivation index (ADI), on bAVM outcome., Methods: A retrospective analysis of an institutional bAVM database was conducted. Non-hereditary hemorrhagic telangiectasia patients with a single unruptured bAVM in the period from 1990 to 2021 were included in the analysis. The ADI was categorized as low (ADI ≤ 15th percentile), mid (15th percentile < ADI < 85th percentile), and high (ADI ≥ 85th percentile), with a low ADI indicating the most advantaged group. Patient baseline and follow-up data were analyzed. The primary outcome of interest was nonindependence (modified Rankin Scale [mRS] score > 2) at the last follow-up. A multivariable logistic regression model was performed., Results: A total of 589 patients with unruptured bAVMs were included in the study. The mean patient age at diagnosis was 37.2 years, and 283 patients (48.0%) were male. Of the bAVMs, 238 (40.4%) had a low Spetzler-Martin grade (SMG < III), 194 (32.9%) had a moderate grade (SMG III), and 157 (26.7%) had a high grade (SMG > III). Sixty-nine patients (11.7%) were in the low-ADI group, 476 (80.8%) in the mid-ADI group, and 44 (7.5%) in high-ADI group. Increasing age (OR 1.02, 95% CI 1.01-1.04, p < 0.001), poor baseline mRS score (OR 3.27, 95% CI 1.32-7.88, p = 0.008), treatment with surgery plus radiosurgery with or without embolization (OR 3.21, 95% CI 1.03-9.81, p = 0.041), mid SMG (OR 1.94, 95% CI 1.11-3.44, p = 0.021), high SMG (OR 2.08, 95% CI 1.13-3.88, p = 0.020), longer follow-up (OR 1.05, 95% CI 1.03-1.08, p < 0.001), and mid ADI (OR 3.08, 95% CI 1.34-8.39, p = 0.015) were significantly associated with a poor outcome. A high ADI tended toward a poor outcome (OR 2.93, 95% CI 0.92-9.88, p = 0.071). Eventual obliteration of a bAVM was the only protective predictor of poor outcome (OR 0.55, 95% CI 0.30-0.98, p = 0.046)., Conclusions: This study revealed that relatively disadvantaged patients with unruptured bAVMs are more likely to experience nonindependent outcomes at the last follow-up, after adjusting for confounding variables. An emphasis on social support may be beneficial for patients with a lower SES.

Background and Objectives: Natural history of hemorrhage in brain arteriovenous malformations (bAVM) is reported at 2%-4% per year. Published studies using survival analysis fail to account for recurrent hemorrhagic events. In this study, we present a large, single institution series to elucidate the natural history of bAVM using multivariable Poisson regression., Methods: This is a retrospective cohort study. All patients with bAVM seen at our institution from 1990 to 2021 were included. Hemorrhages after detection of bAVM during the untreated interval were recorded. Natural history of hemorrhage was calculated by dividing number of hemorrhages by untreated interval. The frequency of hemorrhages followed a Poisson distribution. Multivariable Poisson regression with an offset variable of untreated interval in patient-years was constructed. Model selection was through a stepwise Akaike information criterion method. Stratified hemorrhagic rate was presented using different combinations of significant factors., Results: A total of 1066 patients with nonhereditary hemorrhagic telangiectasia harboring a single bAVM were included. Ninety (8.44%) patients had 101 hemorrhages during an untreated interval of 3596.3344 patient-years, translating to an overall hemorrhagic rate of 2.81% per year. Significant factors increasing hemorrhage risk included ruptured presentation ( P < .001), increasing age ( P < .001), female sex ( P = .043), and deep location ( P = .040). Adult male patients with ruptured presentation and deep bAVMs sustained the highest annual risk at 10.81%, whereas no hemorrhages occurred in unruptured pediatric male patients or ruptured pediatric (younger than 18 years) male patients with superficial bAVMs., Conclusion: Hemorrhage after bAVM detection occurs in 8.41% of all patients, and the rate averages 2.81% per year. However, this risk varies from 0.00% to 10.81% per year depending on various risk factor combinations. Efforts should be made to stratify bAVM hemorrhage rate by risk factors for more precise estimation of bleeding risk if left untreated., (Copyright © Congress of Neurological Surgeons 2023. All rights reserved.)

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., (Copyright © 2018 by the Congress of Neurological Surgeons.)

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 < .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.

Background: Posterior fossa arteriovenous malformations (AVMs) are associated with increased risk of rupture and severe consequences from such rupture. The hemorrhagic risk of prenidal aneurysms (anr) on the posterior inferior cerebellar artery (PICA) may exceed that of the AVM in posterior fossa AVMs fed by PICA (PICA-AVM)., Objective: To characterize the relative risks of aneurysm and AVM hemorrhage in patients with posterior fossa AVMs., Methods: We retrospectively reviewed patients diagnosed with AVM. Patients with posterior fossa AVMs were divided into 3 groups: PICA-AVM with prenidal aneurysm (PICA-AVM-anr group), PICA-AVM without prenidal aneurysm (PICA-AVM group), and AVMs without PICA feeder with/without aneurysm (AVM-only group). Patient and lesion characteristics and treatment outcomes were compared. ANOVA and chi squared tests were used for statistical analyses., Results: Our cohort included 85 patients. Mean age was 45.3 ± 18.1 yr, with 43(50.6%) female patients. Fifty-one patients (60.0%) had hemorrhagic presentation, and 27 (31.8%) experienced acute hydrocephalus. Patients in the PICA-AVM-anr group (n = 11) were more likely to present with aneurysmal subarachnoid hemorrhage (SAH; P = .005) and less likely to have AVM rupture (P < .001). Ten (90.9%) patients presented with hemorrhage, 6 (60.0%) of which resulted from aneurysm rupture. Of these 6, 5 (83.3%) had acute hydrocephalus. No patients with AVM rupture had hydrocephalus. Eight (72.7%) received aneurysm treatment prior to AVM treatment. There were no significant differences in post-treatment outcomes dependent on treatment order., Conclusion: In addition to relatively higher risk of AVM rupture from infratentorial location and prenidal aneurysm, a higher risk of aneurysm rupture rather than AVM rupture was observed in patients with PICA-AVM-anr complex.

Background: The Spetzler-Martin grading system for brain arteriovenous malformations (AVMs) is based on size (S), eloquence (E), and deep venous drainage (V). However, variation exists due to subgroup heterogeneity. While previous studies have demonstrated variations in outcomes within grade III AVMs, no studies have focused on grade II AVM subtypes., Objective: We aim to delineate how functional outcomes differ among patients with subtypes of grade II AVMs., Methods: We retrospectively reviewed patients with AVMs evaluated at our institution from 1990 to 2013. Grade II AVMs were divided into 3 subtypes: group 1 (S2V0E0), group 2 (S1V0E1), and group 3 (S1V1E0). Baseline characteristics were compared, and functional status was assessed using the modified Rankin Scale (mRS) at pretreatment and last follow-up. Differences in mRS between the 2 time points were compared., Results: A total of 208 grade II patients (34.0%) were retrieved from 611 graded patients. After accounting for missing data, our cohort consisted of 137 patients. Mean age of all patients was 37.2 years, with 74 females (54.0%). No significant difference was observed across subgroups for pretreatment mRS ( P = .096), treatment modalities ( P = .943), follow-up durations ( P = .125), and mRS at last follow-up ( P = .716). In a subgroup analysis between group 1 and group 3, more patients with worsened mRS were observed in group 3 ( P = .039). This distinction was further confirmed in surgically treated patients ( P = .049), but not in patients treated with radiosurgery ( P = .863)., Conclusion: 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., (Copyright © 2017 by the Congress of Neurological Surgeons)

Background: Seizure risk has not been fully characterized in pediatric patients with arteriovenous malformations (AVMs)., Objective: To describe the progression and risk factors of post-treatment seizure in children with AVMs., Methods: We retrospectively reviewed pediatric patients diagnosed with intracranial AVMs at our institution between 1990 and 2013. Clinical and angiographic variables were included in univariate and multivariate Cox proportional hazard models to explore risk factors associated with time-related seizure outcomes. The outcome event is defined as first seizure occurrence after initial treatment. Kaplan-Meier survival curve is depicted for each significant variable, and survival differences were confirmed by Log-rank test., Results: We included 90 pediatric patients with complete data in our study cohort. Average age is 13.3 ± 3.8 years with 43.3% male patients. Thirty-seven patients had a hemorrhagic presentation, and 39 patients presented with seizure. Post-treatment seizure occurred in 33 patients (36.7%) over an average follow-up period of 8.1 ± 10.6 years; average time to onset is 5.3 ± 8.2 years, with partial seizures as the most common presentation. Multivariate Cox proportional hazard regression revealed seizure presentation ( P = .005), male gender ( P = .026), and nonconservative treatment modality to be significantly associated with earlier onset of post-treatment seizure after adjusting for AVM location and deep venous drainage. Overall annualized seizure risk is 7.4% for patients with pretreatment seizure, and 1.4% for those without., Conclusion: Risk of seizure persists after treatment in pediatric AVM patients. Seizure presentation, male gender, and nonconservative management are associated with increased risk of post-treatment seizure. Early identification of these risk factors provides important information for determining seizure management strategies., (Copyright © 2017 by the Congress of Neurological Surgeons)

Treatment selection for patients 60years of age and older with intracranial arteriovenous malformations (AVMs), requires careful consideration of the natural history and post-treatment hemorrhagic risk. We aimed to directly compare the natural history of AVMs with post-treatment hemorrhagic risk in this population. We retrospectively reviewed our AVM database of 683 patients. Patients ⩾60years at diagnosis were included. Treatment modality was divided into four groups: surgery±embolization (SE), radiosurgery±embolization (RE), embolization only (Emb), and observation (Obs). The natural history of the AVM was defined as the annual risk of hemorrhage under observation. Risk of hemorrhage after treatment was also calculated. Sixty-one patients with complete data were included. Average age was 68.4±7.5years, with 55.7% (n=34) being male. Twenty-seven (44.3%) patients presented with intracerebral hemorrhage (ICH). At last follow-up, modified Rankin Scale was higher in patients with subsequent hemorrhages (p=0.023). Overall, obliteration was 65.5%, with 100.0% in the SE group and 43.8% in the RE group (p<0.001). During an average follow-up period of 2.8±3.2years, six patients (9.8%) experienced hemorrhage, with two (12.5%) in the RE group, three (9.4%) in the Obs group and one (9.1%) in the SE group, corresponding to a natural history of 3.5% annual hemorrhage rate and a post-treatment hemorrhagic risk of 3.6%. This post-treatment hemorrhage risk was 2.4% in the SE group and 4.9% in the RE group. Presenting with ICH (p=0.042) and race (p=0.014) were associated with a higher risk of follow-up hemorrhage. Definitive treatment for AVM patients ⩾60years should be cautiously considered. Despite higher post-treatment obliteration rates, the subsequent hemorrhagic risk may exceed that of its natural history. For AVMs with a high risk for hemorrhage, surgery reduces hemorrhagic risk and achieves the highest rate of obliteration., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Introduction: Management decisions for brainstem arteriovenous malformations (AVMs) are complicated by balancing the risks of treatment and natural progression to hemorrhage. The present study seeks to compare radiosurgery and conservative management outcomes in brainstem AVMs., Methods: We performed a retrospective review of patients with brainstem AVM seen at our institution from 1990 to 2013. Patients missing baseline information or those lost to follow-up were excluded. Clinical and angiographic characteristics and subsequent hemorrhagic risk were evaluated according to brainstem AVM location and treatment modality., Results: We identified 30 patients with brainstem AVM with complete data. Mean age was 41.6 ± 20.3 years, and 53.3% (n = 16) were male. Sixteen (53.3%) presented with hemorrhage. Twelve patients (40.0%) were conservatively managed, and 18 were treated. Sixteen (88.9%) of the treated patients underwent radiosurgery, 1 (5.6%) underwent surgery, and 1 (5.6%) underwent embolization only. Average follow-up period was 4.7 ± 5.7 years, and 5 patients (16.7%) experienced recurrent hemorrhage, 3 of whom were in the radiosurgery group and 2 in the conservative group, giving an annual recurrent hemorrhage risk of 3.7% and 4.8%, respectively. Lesion obliteration was achieved in 8 patients (26.7%). Baseline clinical and angiographic factors were similar between the radiosurgery and conservative group. Obliteration was achieved in 43.8% of those treated with radiosurgery (P = 0.008). Despite similar baseline modified Rankin Scale scores, more patients had improvement of modified Rankin Scale score at last follow-up in the radiosurgery group (P = 0.004). Recurrent hemorrhage during follow-up was similar between the 2 groups (P = 0.887)., Conclusions: Our results suggest that when patients with brainstem AVM are selected cautiously, radiosurgery may achieve obliteration and symptom relief without increasing subsequent hemorrhage risk., (Copyright © 2016 Elsevier Inc. All rights reserved.)

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.

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 >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 < .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 < 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., Abbreviations: AVM, arteriovenous malformationmRS, modified Rankin Scale.

Background: Patients diagnosed with hereditary hemorrhagic telangiectasia (HHT) are at risk of developing intracranial arteriovenous malformations (AVM). However, the clinical manifestations and natural history of HHT-related AVMs remain unclear due to the rarity of these lesions., Objective: To clarify the clinical characteristics and hemorrhagic risk in HHT-related AVMs., Methods: We performed a retrospective review of all patients diagnosed with both HHT and intracranial AVMs who were evaluated at our institution from 1990 to 2013. Patients with missing data or lost to follow-up were excluded. Baseline characteristics and subsequent hemorrhagic risk were evaluated., Results: In an AVM database of 531 patients with 542 AVMs, a total of 12 HHT patients (2.3%) with 23 AVMs were found. Mean age at diagnosis was 36.5 years, with 41.7% male. Compared to patients with sporadic AVMs, patients with HHT were less likely to present with ruptured AVM (P = .04), headaches (P = .02), and seizures (P = .02), and presented with better modified Rankin scores (P < .01). HHT-related AVMs were smaller in size (P < .01), of lower Spetzler-Martin grade (P = .01), and had less temporal lobe involvement (P = .02) compared to sporadic AVMs. Six HHT patients (50.0%) were found with multiple intracranial AVMs. One hemorrhage was found during an observation period of 149.6 patient-years and 297.5 lesion-years, translating to 1.3% per patient per year or 0.7% per AVM per year., Conclusion: HHT-related AVMs are smaller in size with lower Spetzler-Martin grade and less temporal lobe involvement than sporadic AVMs. Patients with HHT frequently present with multiple intracranial AVMs. Conservative management is generally recommended due to lesion multiplicity and relatively low hemorrhagic risk.

Objective: The risk of delayed hemorrhage occurring greater than 2 years after treatment in brain arteriovenous malformations (AVMs) rarely is reported. In this study, we compare the risk of delayed hemorrhage across different treatment modalities., Methods: We performed a retrospective chart review of treated patients with a single intracranial AVM seen at our institution from 1990 to 2013. Delayed hemorrhage was defined as hemorrhage occurring at least 2 years after last treatment. Survival analysis was used to assess risk of delayed hemorrhage by treatment modalities., Results: Our study included 420 patients. Spetzler-Martin grades were as follows: I (12.6%), II (36.2%), III (32.6%), IV (15.0%), and V (3.6%). Average follow-up time is 5.1 years. Twenty-two patients (5.2%) were found to have 28 delayed hemorrhages. Average interval between last treatment and delayed hemorrhage was 7.6 years, with the longest being 24.2 years. Proportions of delayed hemorrhages by treatment modalities were as follows: surgery ± embolization (group I, 9.1%), radiosurgery ± embolization (group II, 63.6%), embolization only (group III, 22.7%), and surgery + radiosurgery ± embolization (group IV, 4.5%). Annualized hemorrhage risk after 2 years for each treatment group was as follows: group I (0.4%), group II (1.2%), group III (3.7%), and group IV (1.7%). Survival analysis demonstrated lowest risk of delayed hemorrhage for group 1 (P < 0.01)., Conclusions: This study is the first to compare the risk of delayed hemorrhage across different treatment modalities. Surgical resection is associated with the lowest risk for delayed hemorrhage compared with other treatment modalities. Patients with partially embolized AVMs should seek timely definitive treatment to decrease the risk of delayed hemorrhage., (Copyright © 2016 Elsevier Inc. All rights reserved.)