Unruptured Arteriovenous Malformations Research Articles

Unveiling the domino effect: a nine-year follow-up on pentalogy of central nervous system induced by a large unruptured cerebral arteriovenous malformation: a case report and literature review

BackgroundThe disruption of intracranial fluid dynamics due to large unruptured cerebral arteriovenous malformation (AVM) commonly triggers a domino effect within the central nervous system. This phenomenon is frequently overlooked in prior clinic and may lead to catastrophic misdiagnoses. Our team has documented the world’s first case of so-called AVM Pentalogy (AVMP) induced by a AVM.Clinical presentation and resultA 30-year-old female was first seen 9 years ago with an occasional fainting, at which time a huge unruptured AVM was discovered. Subsequently, due to progressive symptoms, she sought consultations from several prestigious neurosurgical departments in China, where all consulting neurosurgeons opted for conservation treatment due to perceived surgical risks. During the follow-up period, the patient gradually presented with hydrocephalus, empty sella, secondary Chiari malformation, syringomyelia, and scoliosis (we called as AVMP). When treated in our department, she already displayed numerous symptoms, including severe intracranial hypertension. Our team deduced that the hydrocephalus was the primary driver of her AVMP symptoms, representing the most favorable risk profile for intervention. As expected, a ventriculoperitoneal shunt successfully mitigated all symptoms of AVMP at 21-months post-surgical review.ConclusionDuring the monitoring of unruptured AVM, it is crucial to remain vigilant for the development or progression of AVMP. When any component of AVMP is identified, thorough etiological studies and analysis of cascade reactions are imperative to avert misdiagnosis. When direct AVM intervention is not viable, strategically addressing hydrocephalus as part of the AVMP may serve as the critical therapeutic focus.

Changes in inpatient brain arteriovenous malformation management in the United States following the ARUBA trial: analysis of an interrupted time series design

The November 2013 online publication of ARUBA, the first multi-institutional randomized controlled trial for unruptured brain arteriovenous malformations (AVMs), has sparked over 100 publications in protracted debates MethodsThis study sought to examine inpatient management patterns of brain AVMs from 2009 to 2016 and observe if changes in U.S. inpatient management were attributable to the ARUBA publication using interrupted time series of brain AVM studies from the National Inpatient Sample data 2009–2016. Outcomes of interest were use of embolization, surgery, combined embolization and microsurgery, radiotherapy, and observation during that admission. An interrupted time series design compared management trends before and after ARUBA. Segmented linear regression analysis tested for immediate and long-term impacts of ARUBA on management. ResultsElective and asymptomatic patient admissions declined 2009–2016. In keeping with the ARUBA findings, observation for unruptured brain AVMs increased and microsurgery decreased. However, embolization, radiosurgery, and combined embolization and microsurgery also increased. For ruptured brain AVMs, treatment modality trends remained positive with even greater rates of observation, embolization, and combined embolization and microsurgery occurring after ARUBA (data on radiosurgery were scarce). None of the estimates for the change in trends were statistically significant. ConclusionsThe publication of ARUBA was associated with a decrease in microsurgery and increase in observation for unruptured brain AVMs in the US. However, inpatient radiotherapy, embolization, and combined embolization and surgery also increased, suggesting trends moved counter to ARUBA’s conclusions. This analysis suggested that ARUBA had a small impact as clinicians rejected ARUBA’s findings in managing unruptured brain AVMs.

Angiographic Evolution of Brain Arteriovenous Malformation Angioarchitecture After Partial Endovascular Treatment.

Endovascular embolization of brain arteriovenous malformations (AVMs) is sometimes intentionally partial, in the case of staged treatment for instance. Residual AVMs may be prone to angioarchitectural modification during follow-up. The objective of this work is to evaluate the nature and extent of these modifications. We performed a retrospective monocentric study on a cohort of adult patients treated by incomplete endovascular embolization for ruptured and unruptured AVMs with an available angiographic follow-up, without any intervening confounding event between the 2 angiographic examinations. AVM angioarchitectural modifications (arterial, nidal, and venous) were analyzed. Clinical and radiological data were tested in univariate analyses for association with the occurrence of AVM regression or progression. Eighty-two partial embolization sessions in 57 patients were included in the study. A 40% (33/82) rate of modification was found on follow-up, with 23/82 (28%) controls showing at least one angioarchitectural regression feature and 15/82 (18.3%) showing at least one angioarchitectural progression item. Nidal growth was the most frequent modification occurring after 12/82 (14.6%) embolizations. The only factor associated with nidal volume growth was a longer time interval between embolization and follow-up (median [IQR]: 190 [250] days vs 89.5[133] days in the subgroup without nidal growth; P = .02). Specific modifications of arterial supply, nidal anatomy, and venous drainage were identified and documented. Angioarchitectural modifications (both progression and regression) of brain AVMs are frequent findings after partial embolization. Nidal volume growth is associated with longer time intervals between embolization and follow-up.

313 Development and Validation of a Scoring System for Hemorrhage Risk in Brain Arteriovenous Malformations

INTRODUCTION: The dilemma between natural rupture risk and adverse outcomes of intervention is of major concern for patients with unruptured arteriovenous malformations (AVMs). The existing risk score for AVM rupture includes factors that are controversial and lacks prospective validation. METHODS: This prognostic study developed a prediction model derived from a single-center cohort (derivation cohort) and validated in a multicenter external validation cohort and a conservative treatment validation cohort. Patients were recruited from a nationwide multicenter prospective collaboration registry in China. A total of 4135 patients were enrolled. 3962 patients were included (3585 in the derivation cohort and 377 in the multicenter external validation cohort); 1028 patients from the derivation cohort who had time-to-event data and prerupture imaging results were included in the conservative treatment validation cohort. RESULTS: Four risk factors were used to develop the scoring system: ventricular system involvement, venous aneurysm, deep location, and exclusively deep drainage (VALE). The VALE scoring system performed well in all 3 cohorts, with areas under the receiver operating characteristic curve of 0.77 (95% CI, 0.75-0.78) in the derivation cohort, 0.85 (95% CI, 0.81-0.89) in the multicenter external validation cohort, and 0.73 (95% CI, 0.65-0.81) in the conservative treatment validation cohort. The 10-year hemorrhage-free rate was 95.5% (95% CI, 87.1%-100%) in the low-risk group, 92.8% (95% CI, 88.8%-97.0%) in the moderate-risk group, and 75.8% (95% CI, 65.1%-88.3%) in the high-risk group; the model discrimination was significant when comparing these rates between the high-risk group and the low- and moderate-risk groups (p < .001 for both comparisons). CONCLUSIONS: In this prognostic study, the VALE scoring system was developed to distinguish rupture risk among patients with AVMs. The stratification of unruptured AVMs may enable patients with low risk of rupture to avoid unnecessary interventions.

691 Correlation of Cerebral Arteriovenous Malformation Flow Measured by Quantitative Magnetic Resonance Angiography and MR-detected Arteriovenous Malformation Microhemorrhage

INTRODUCTION: Intracranial hemorrhage (ICH) significantly contributes to morbidity and mortality in cerebral arteriovenous malformations (AVM) patients, with a history of prior hemorrhage being the most significant predictor of a future hemorrhage. Recently, silent microhemorrhage as detected on magnetic resonance imaging (MRI) has been proposed as a potential risk factor for future hemorrhage in AVM patients. Recent data suggests that silent microhemorrhage is associated with higher nidal velocity measured through color-coded DSA, raising the question of correlation between flow and microhemorrhage. METHODS: All unruptured AVM patients with a baseline QMRA with noninvasive optimal vessel analysis (NOVA) and gradient echo or susceptibility-weighted MRI were retrospectively reviewed (2004-2022). AVM flow was calculated from the aggregate flow within primary arterial feeders relative to their contralateral counterparts. A review of the MRI determined the presence of microhemorrhages. Descriptive statistics, the X2 test, and a binomial logistic regression were performed to test the association of demographics, clinical, and AVM features with microhemorrhage. RESULTS: The study consisted of ninety patients, with fifty microhemorrhage-positive and forty microhemorrhage-negative patients. The presence of venous anomaly (varix, ectasia, aneurysm) is independently predictive of microhemorrhage (OR = 2.444, p = 0.050), and a compact AVM nidus trended towards independent negative predictability of microhemorrhage (OR =.462, p = 0.081). Calculated AVM flow trends higher in the microhemorrhage-positive group with the median flow 407 mL/min vs. 238 mL/min, and a trend towards predicting presence of microhemorrhage (OR = 1.375, p = 0.106). CONCLUSIONS: Patients with AVM-associated venous anomalies have an increased likelihood of AVM microhemorrhage. Higher AVM flow and a diffuse AVM nidus trend towards a higher likelihood of AVM microhemorrhage. These findings demonstrate the possible relationship between higher AVM flow and risk of future bleeding.

Rupture-Related Features of Cerebral Arteriovenous Malformations and Their Utility in Predicting Hemorrhage.

Evaluating rupture risk in cerebral arteriovenous malformations currently lacks quantitative hemodynamic and angioarchitectural features necessary for predicting subsequent hemorrhage. We aimed to derive rupture-related hemodynamic and angioarchitectural features of arteriovenous malformations and construct an ensemble model for predicting subsequent hemorrhage. This retrospective study included 3 data sets, as follows: training and test data sets comprising consecutive patients with untreated cerebral arteriovenous malformations who were admitted from January 2015 to June 2022 and a validation data set comprising patients with unruptured arteriovenous malformations who received conservative treatment between January 2009 and December 2014. We extracted rupture-related features and developed logistic regression (clinical features), decision tree (hemodynamic features), and support vector machine (angioarchitectural features) models. These 3 models were combined into an ensemble model using a weighted soft-voting strategy. The performance of the models in discriminating ruptured arteriovenous malformations and predicting subsequent hemorrhage was evaluated with confusion matrix-related metrics in the test and validation data sets. A total of 896 patients (mean±SD age, 28±14 years; 404 women) were evaluated, with 632, 158, and 106 patients in the training, test, and validation data sets, respectively. From the training set, 9 clinical, 10 hemodynamic, and 2912 pixel-based angioarchitectural features were extracted. A logistic regression model was built using 4 selected clinical features (age, nidus size, location, and venous aneurysm), whereas a decision-tree model was constructed from 4 hemodynamic features (outflow time, stasis index, cerebral blood flow, and outflow volume ratio). A support vector machine model was designed using 5 pixel-based angioarchitectural features. In the validation data set, the accuracy, sensitivity, specificity, and area under the curve of the ensemble model for predicting subsequent hemorrhages were 0.840, 0.889, 0.823, and 0.911, respectively. The ensemble model incorporating clinical, hemodynamic, and angioarchitectural features showed favorable performance in predicting subsequent hemorrhage of cerebral arteriovenous malformations.

Management of sporadic intracranial vascular malformations in pregnancy: a retrospective analysis

BackgroundSporadic intracranial vascular malformations can pose significant risk to parturients, and additional reports of management may inform patient care. Here we describe the peripartum management of parturients with intracranial vascular malformations. MethodsAfter Institutional Review Board approval, we performed a retrospective analysis of parturients with a known sporadic intracranial vascular malformation including cavernous malformation, developmental venous anomaly, or arteriovenous malformation who delivered at our institution between 2007 and 2020. ResultsWe identified 10 parturients (five cavernous malformations, three developmental venous anomalies, and two arteriovenous malformations) with 16 deliveries. Among all deliveries, 13 (81.3%) were cesarean deliveries without trial of labor; 11 of these (84.6%) received a single-shot spinal and two (15.4%) received an epidural for surgical anesthesia. Two deliveries (12.5%) began with attempted trial of labor but ultimately required cesarean delivery for failure to progress; one of these cases received epidural anesthesia and the other received combined spinal-epidural anesthesia. One delivery was via spontaneous vaginal delivery with epidural analgesia. Overall, our study’s cesarean delivery rate was 93.8% and spontaneous vaginal delivery rate was 6.2%.Three of 16 pregnancies were complicated by seizure, obstructive hydrocephalus, or intracranial hemorrhage. There were no intensive care unit admissions or maternal deaths. ConclusionsIn our case series of 16 deliveries, there were no complications directly resulting from neuraxial procedures. It remains unclear whether intracranial developmental venous anomalies or unruptured arteriovenous malformations impart increased risk during pregnancy. Antepartum planning with a multidisciplinary team approach enables risk stratification and optimal management.

Hematologic and Inflammatory Predictors of Outcome in Patients with Brain Arteriovenous Malformations

This study investigated the prognostic value of admission blood counts for arteriovenous malformation (AVM) outcomes and compared admission blood counts for patients with ruptured and unruptured AVMs. A retrospective analysis of patients who underwent surgical treatment for a ruptured cerebral AVM between February 1, 2014, and March 31, 2020, was conducted. The primary outcome was poor neurologic outcome, defined as a modified Rankin Scale score ≥2 in patients with unruptured AVMs or >2 in patients with ruptured AVMs. Of 235 included patients, 80 (34%) had ruptured AVMs. At admission, patients with ruptured AVMs had a significantly lower mean (SD) hemoglobin level (12.78 [2.07] g/dL vs. 13.71 [1.60] g/dL, P < 0.001), hematocrit (38.1% [5.9%] vs. 40.7% [4.6%], P < 0.001), lymphocyte count (16% [11%] vs. 26% [10%], P < 0.001), and absolute lymphocyte count (1.41 [0.72]× 103/μL vs. 1.79 [0.68]× 103/μL, P < 0.001), and they had a significantly higher mean (SD) white blood cell count (10.4 [3.8]× 103/μL vs. 7.6 [2.3]× 103/μL, P < 0.001), absolute neutrophil count (7.8 [3.8]× 103/μL vs. 5.0 [2.5]× 103/μL, P < 0.001), and neutrophil count (74% [14%] vs. 64% [13%], P < 0.001). Among patients with unruptured AVMs, white blood cell count ≥6.4× 103/μL and absolute neutrophil count ≥3.4× 103/μL were associated with a favorable neurologic outcome, whereas hemoglobin level ≥13.4 g/dL was associated with an unfavorable outcome. Among patients with ruptured AVMs, hypertension was associated with a 3-fold increase in odds of a poor neurologic outcome. Patients with ruptured and unruptured AVMs present with characteristic profiles of hematologic and inflammatory parameters evident in their admission blood work.

The correlation of cerebral arteriovenous malformation flow measured by quantitative MR angiography on MR-detected arteriovenous malformation microhemorrhage

OBJECTIVE The objective of this study was to assess the relationship of arteriovenous malformation (AVM) blood flow measured by quantitative MR angiography (QMRA) in nonruptured AVMs with MR-detected microhemorrhage. METHODS All patients with unruptured AVMs who received baseline QMRA and gradient echo or susceptibility-weighted MRI were retrospectively reviewed (2004–2022). Imaging data, clinical history, and AVM angioarchitectural and flow features were collected and assessed. AVM flow was calculated from the difference of flow within primary arterial feeders from their contralateral counterparts. A review of the MR images determined the presence of microhemorrhages. Analysis of descriptive statistics, chi-square test, and binomial logistic regression were performed. RESULTS Of 634 patients with cerebral AVMs at a single center, 89 patients met the inclusion criteria (54 with microhemorrhage and 35 without microhemorrhage). The calculated AVM flow was significantly higher in the group with a microhemorrhage (447.9 ± 193.1 ml/min vs 287.6 ± 235.7 ml/min, p = 0.009). In addition, the presence of venous anomaly, arterial ectasia, and diffuse nidus was significantly associated with microhemorrhage (p = 0.017, p = 0.041, and p = 0.041, respectively). Binary logistic regression found that higher flow predicted the presence of microhemorrhage (OR 1.002, 95% CI 1.000–1.004; p = 0.031). The highest AVM flow quartile significantly predicted the presence of venous anomaly (OR 3.840, 95% CI 1.037–14.213; p = 0.044), diffuse nidus (OR 6.800, 95% CI 1.766–25.181; p = 0.005), and arterial ectasia (OR 13.846, 95% CI 1.905–122.584; p = 0.018). CONCLUSIONS This study represents the first to examine the association between flow measurements on QMRA with microhemorrhage in unruptured AVMs. Higher AVM flow, venous anomaly, arterial ectasia, and diffuse AVM nidus were related to a higher likelihood of AVM microhemorrhage. Higher AVM flow was present in AVMs with venous anomalies, a diffuse nidus, and arterial ectasia, indicating a possible interaction between these angioarchitectural findings, AVM flow, and microhemorrhage. These findings suggest a relationship between higher AVM flow and the risk of microhemorrhage.

Stereotactic radiosurgery for brain arteriovenous malformations in patients with hereditary hemorrhagic telangiectasia

ObjectiveBrain arteriovenous malformations (AVMs) in patients with hereditary hemorrhagic telangiectasia (HHT) present different characteristics from sporadic AVMs, and they have lower initial bleeding rates. Conservative management is usually preferred for the treatment of these lesions. In this case study, we present the largest series of HHT patients treated with stereotactic radiosurgery to date.MethodsWe identified eight patients with HHT and 14 AVMs. We retrospectively collected clinical, radiographic, and treatment characteristics of the patients and each AVM.ResultsMost patients in our sample presented with small AVMs. The median volume of these AVMs was 0.22 cm3 (IQR 0.08–0.59). Three out of eight patients presented with initial intracerebral hemorrhage (ICH). The majority of lesions had low (12/14) Spetzler-Martin grades (I–II). Median maximum and margin doses used for treatment were 36.2 (IQR 35.25–44.4) and 20 (IQR 18–22.5) Gy, respectively. The overall obliteration rate after SRS was 11/14, and the median time to obliteration across all 11 obliterated AVMs was 35.83 months (IQR, 17–39.99). Neurological status was favorable with all patients having a mRS of 0 or 1 at the last follow-up. Symptomatic radiation-induced changes (RIC) after SRS were low (7.1%), and there were no permanent RIC.ConclusionsPatients with HHT who present with multiple brain AVMs are generally well served by SRS. Obliteration can be achieved in the majority of HHT patients and with a low complication rate. In the current study, initial hemorrhage rates prior to SRS were noticeable which supports the decision to treat these AVMs. Future studies are needed to better address the role of SRS for HHT patients harboring ruptured and unruptured AVMs.

Treatment outcomes for ARUBA-eligible brain arteriovenous malformations: a comparison of real-world data from the NVQI-QOD AVM registry with the ARUBA trial

BackgroundSignificant controversy exists about the management of unruptured cerebral arteriovenous malformations (AVMs). Results from A Randomized Trial of Unruptured Brain Arteriovenous Malformations (ARUBA) suggested that intervention increases the risk of...

Mixed reality in neurosurgery: redefining the paradigm for arteriovenous malformation planning and navigation to improve patient outcomes.

Brain arteriovenous malformations (AVMs) present significant challenges in neurosurgery, requiring detailed planning and execution. In this study, the authors aimed to evaluate the efficacy of mixed reality (MxR), a synergistic application of virtual reality (VR) and augmented reality (AR), in the surgical management of AVMs. A retrospective review was conducted on 10 patients who underwent AVM resection between 2021 and 2023. Preoperative planning used patient-specific 360° VR models, while intraoperative guidance used AR markers for targeted disconnection of arterial feeders. Data were analyzed for surgical duration, blood loss, and postoperative outcomes, stratified by Spetzler-Martin (SM) and supplemented Spetzler-Martin (Supp-SM) grades. In 10 patients with cerebral AVMs, MxR significantly facilitated the identification of 21 arterial feeders, including challenging deep feeders. MxR-assisted surgeries demonstrated efficient identification and disconnection of arterial feeders, contributing to precise AVM resection. The mean surgical duration was approximately 5 hours 11 minutes, with a mean intraoperative blood loss of 507.5 ml. Statistically significant variations in surgical duration and blood loss were observed based on SM and supplemented Supp-SM grades. Two patients experienced worsened postoperative neurological deficits, underscoring the inherent risks of AVM surgeries. The marked difference in hospital stays between patients with ruptured and those with unruptured AVMs, particularly for SM grade III, highlights the significant impact of rupture status on postoperative recovery. In this study, the authors delineated a novel paradigm using MxR for the surgical intervention of AVMs. Using 3D VR for preoperative planning and AR for intraoperative guidance, they achieved unparalleled precision and efficiency in targeting deep arterial feeders. While the results are promising, larger studies are needed to further validate this approach.

Primary endovascular embolisation of intracranial arteriovenous malformations (AVM)-UK single centre experience.

Intracranial arteriovenous malformations (AVMs) treated at our institution with modern techniques of endovascular intervention were analysed for the rate of complete occlusion, associated morbidity, and mortality. To our knowledge, this is the first series from the UK evaluating the effectiveness of endovascular embolisation as a primary treatment for selected cases. All newly referred AVMs between January 2017 and June 2022 were reviewed and those treated with primary endovascular intervention were identified. Details of the endovascular procedures were retrospectively reviewed. In 5½ years, 41.1% of AVMs referred to our institution have been triaged for primary endovascular intervention. Sixty-eight AVMs were embolised and followed-up: 44 ruptured and 24 unruptured. Spetzler-Martin grading varied from I to III, and a single AVM was grade IV. The approach was arterial in 73.5%, solely venous in 7.4%, and combined in 19.1%. The mean follow-up was 18 months for imaging and 26 months for clinical assessment. Complete obliteration was achieved in 95.6%. Ruptured AVM cohort: The rate of functional deterioration was 13.6%. Unruptured AVM cohort: The rate of functional deterioration secondary to complications from embolisation was 4.2%. Endovascular embolisation may be a favourable option for primary AVM treatment in carefully selected patients. However, selection criteria need to be better delineated for more specialists to consider this as a primary therapy.

Comparison of conservative management, microsurgery only, and microsurgery with preoperative embolization for unruptured arteriovenous malformations: A propensity score weighted prospective cohort study.

To compare the efficacy and deficiency of conservative management (CM), microsurgery (MS) only, and microsurgery with preoperative embolization (E + MS) for unruptured arteriovenous malformations (AVMs). We prospectively included unruptured AVMs undergoing CM, MS, and E + MS from our institution between August 2011 and August 2021. The primary outcomes were long-term neurofunctional outcomes and hemorrhagic stroke and death. In addition to the comparisons among CM, MS, and E + MS, E + MS was divided into single-staged hybrid and multi-staged E + MS for further analysis. Stabilized inverse probability of treatment weighting using propensity scores was applied to control for confounders by treatment indication across the three groups. Of 3758 consecutive AVMs admitted, 718 patients were included finally (266 CM, 364 MS, and 88 E + MS). The median follow-up duration was 5.4 years. Compared with CM, interventions (MS and E + MS) were associated with neurological deterioration. MS could lower the risk of hemorrhagic stroke and death. Multi-staged E + MS was associated with neurological deterioration and higher hemorrhagic risks compared with MS, but the hybrid E + MS operation significantly reduced the hemorrhage risk. In this study, unruptured AVMs receiving CM would expect better neurofunctional outcomes but bear higher risks of hemorrhage than MS or E + MS. The single-staged hybrid E + MS might be promising in reducing inter-procedural and subsequent hemorrhage.

Outcome of 107 conservatively managed unruptured brain arteriovenous malformations: a single center's 30-year experience.

Since the publication of A Randomized Trial of Unruptured Brain AVMs (ARUBA), the management of unruptured brain arteriovenous malformations (bAVMs) has been controversially discussed. Long-term follow-up data on the exclusively conservative management of unruptured bAVMs are scarce. The authors evaluated the long-term outcomes of patients with unruptured untreated bAVMs in a real-life cohort. A retrospective observational cohort of 107 patients (of 897 bAVM patients referred to the authors' institution) with a diagnosis of unruptured and conservatively managed bAVMs is presented. AVMs of all Spetzler-Martin grades were observed. The mean follow-up period was 84 months. In 44% of patients, a follow-up period of 5 years or longer was observed. A national death register comparison completed the outcome analysis. The median age at diagnosis, sex distribution, neurological presentation, and modified Rankin Scale score were comparable to the patients in the medical management arm of the ARUBA study. Patients were mainly young, predominantly male, and in good clinical condition. Similar to the ARUBA cohort, 77% of this study's cohort presented in an excellent clinical status at the time of last follow-up. However, 17% of patients had at least one hemorrhage, resulting in an overall annual hemorrhage risk of 2.7% in the observation period. Moreover, the cumulative 1-, 5-, and 10-year overall hemorrhage rates were 3.0%, 11.3%, and 15.3%, respectively. Consequently, the long-term follow-up AVM-related mortality rate amounted to 8%. The estimated median overall survival after AVM diagnosis was 19.3 years (95% CI 14.0-24.6 years). A multivariate Cox regression model revealed temporal and deep-seated localization as an independent risk factor for AVM hemorrhage, while the presence of seizures reached borderline significance as a risk factor. The authors' results represent the long-term course of unruptured untreated bAVMs. Their data support the conclusion that even in the post-ARUBA era, tailored active treatment options may be offered to patients with unruptured bAVMs. For patient counseling, individual risk factors should be weighed against the center's treatment-specific risks.

Partial Onyx embolization triggers spontaneous regression of cerebral AVM: A case report

Spontaneous regression of a cerebral arteriovenous malformations (AVMs) is a rare and poorly understood phenomenon. We present a case of unruptured cerebral AVM in a patient presenting with intermittent headache. In order to reduce hemorrhagic risk, the patient underwent partial embolization of the AVM with Onyx glue. Follow-up digital subtraction angiography (DSA) showed complete obliteration of the residual AVM three months after the treatment. In conclusion, partial Onyx embolization of cerebral AVM may be an etiological factor of spontaneous regression. In order to reduce hemorrhagic risk, targeted partial embolization of the AVM may be an alternative treatment for some cases.

Impact of COVID-19 pandemic on treatment and outcomes of cerebral arteriovenous malformations

BackgroundThere has been a recent decrease in interventional management of cerebral arteriovenous malformations (AVMs). The objective of our study was to evaluate the changing patterns in management of AVMs in...

Growth of Flow-Related Aneurysms Following Occlusion of Cerebral Arteriovenous Malformation.

Flow-related aneurysms (FRAs) associated with cerebral arteriovenous malformations (AVMs) pose a significant therapeutic challenge. Both their natural history and management strategy are still unclear and underreported. FRAs generally increase the risk of brain hemorrhage. However, following AVM obliteration these vascular lesions are expected to disappear or remain stable. We present two cases where growth of FRAs was detected following complete obliteration of an unruptured AVM. The first patient presented with proximal middle cerebral artery (MCA) aneurysm growth after spontaneous and asymptomatic thrombosis of the AVM. In our second case, a very small aneurysmal-like dilation located at the basilar apex enlarged to a saccular aneurysm following complete endovascular and radiosurgical obliteration of the AVM. The natural history of flow-related aneurysms is unpredictable. In the cases where these lesions are not managed first, there should be close follow-up. When aneurysm growth is evident, active management strategy seems mandatory.

Radiation-induced change after Gamma Knife radiosurgery for cerebral arteriovenous malformations

Objective: Radiation-induced change (RIC) on magnetic resonance imaging after Gamma Knife radiosurgery (GKRS) for cerebral arteriovenous malformations (AVMs) is not rare. We reviewed patients who underwent GKRS for AVMs and analyzed the results and factors associated with RIC.Methods: We reviewed 189 patients who underwent GKRS for AVMs between October 2002 and August 2017. All patients were followed up for at least 3 years. This study included 111 males and 78 females (mean age, 39.63 years; range, 3–79 years). Nineteen patients underwent pre-GKRS embolization. Seventy-six patients had ruptured AVMs and 113 had unruptured AVMs. We analyzed obliteration and RIC occurrence rates. Several demographic and clinical factors were analyzed to determine the influence of AVM obliteration on RIC occurrence.Results: The overall obliteration rate (OR) was 72.49% (137/189) at the final follow-up. The actuarial OR was 55.5% 36 months after GKRS. The overall RIC occurrence rate was 28.04% (53/189), and the actuarial RIC occurrence rate was 26.8% 24 months after GKRS. The OR showed a statistically significant difference according to AVM rupture (p&lt;0.01) and sex (p&lt;0.01). The RIC occurrence rate was significantly associated with AVM rupture (p&lt;0.01), lesion volume (p=0.04), and treatment volume (p=0.03). Other factors showed statistically non-significant relationships.Conclusion: The overall OR after GKRS for AVMs was comparable to the results of other previous reports. RIC is a common postoperative outcome following GKRS for AVMs. In this study, the OR was higher in ruptured AVMs and male patients, whereas RIC occurred more frequently in larger and unruptured AVMs.

Stereotactic radiosurgery outcome for deep-seated cerebral arteriovenous malformations in the brainstem and thalamus/basal ganglia: systematic review and meta-analysis.

Deep-seated unruptured AVMs located in the thalamus, basal ganglia, or brainstem have a higher risk of hemorrhage compared to superficial AVMs and surgical resection is more challenging. Our systematic review and meta-analysis provide a comprehensive summary of the stereotactic radiosurgery (SRS) outcomes for deep-seated AVMs. This study follows the guidelines set forth by the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) Statement. We conducted a systematic search in December 2022 for all reports of deep-seated arteriovenous malformations treated with SRS. Thirty-four studies (2508 patients) were included. The mean obliteration rate in brainstem AVM was 67% (95% CI: 0.60-0.73), with significant inter-study heterogeneity (tau2 = 0.0113, I2 = 67%, chi2 = 55.33, df = 16, p-value < 0.01). The mean obliteration rate in basal ganglia/thalamus AVM was 65% (95% CI: 0.58-0.72) with significant inter-study heterogeneity (tau2 = 0.0150, I2 = 78%, chi2 = 81.79, df = 15, p-value < 0.01). The presence of deep draining veins (p-value: 0.02) and marginal radiation dose (p-value: 0.04) were positively correlated with obliteration rate in brainstem AVMs. The mean incidence of hemorrhage after treatment was 7% for the brainstem and 9% for basal ganglia/thalamus AVMs (95% CI: 0.05-0.09 and 95% CI: 0.05-0.12, respectively). The meta-regression analysis demonstrated a significant positive correlation (p-value < 0.001) between post-operative hemorrhagic events and several factors, including ruptured lesion, previous surgery, and Ponce C classification in basal ganglia/thalamus AVMs. The present study found that radiosurgery appears to be a safe and effective modality in treating brainstem, thalamus, and basal ganglia AVMs, as evidenced by satisfactory rates of lesion obliteration and post-surgical hemorrhage.