Ruptured brain arteriovenous malformations associated with aneurysms: safety and efficacy of selective embolization in the acute phase of hemorrhage

Outcome of early versus late primary embolization in ruptured brain arteriovenous malformations

PURPOSE

To determine whether patients with a ruptured brain arteriovenous malformation (rBAVM) would benefit from an early embolization.

METHODS

rBAVM treated first by embolization between March 2002 and May 2022 were included. Embolization was defined early (Group 1) when performed within 10 days postbleeding. If later, embolization was considered late (Group 2). Demographic and rBAVM data were compared between the groups. High-risk bleeding components and reasons for deferring embolization were retrieved. Primary endpoint was rebleeding. Secondary endpoints were good functional outcome (FO, modified Rankin Scale mRS ≤ 2) and angiographic occlusion. Predictors of rebleeding and FO were determined by multivariate analysis.

RESULTS

105 patients were recruited (N = 34 in Group 1; N = 71 in Group 2). No rebleeding was noted before, during or after the first embolization session in the early embolization group. Late embolization depended on missed diagnosis and referral pattern. Eleven patients (10.5%) suffered a rebleeding, of whom N = 3 before embolization (only in Group 2), N = 5 periembolization (N = 2 at the second embolization session in Group 1) and N = 3 spontaneous more than 30 days postembolization. More high-risk components were embolized in Group 1 (19/34; 55.9 vs 17/71; 23.9%; p = .011). Rebleeding rates, FO at last FU (90.9% vs 74.3%) and occlusion rates (80.8% vs 88.5%) did not differ between the groups. Glasgow coma scale ≤ 8 predicted rebleeding, rebleeding correlated with poor FO.

CONCLUSION

Early embolization did prevent rebleeding. The overall rebleeding risk was linked to bleeding before late embolization and bleeding at the second embolization. Rebleeding predicted the final FO.

Pediatric Cerebral Vascular Malformations : Current and Future Perspectives

Intracranial vascular malformations typically encountered by pediatric neurosurgeons include arteriovenous malformations, vein of Galen malformations and cavernous malformations. While these remain amongst some of the most challenging lesions faced by patients and caregivers, the past decade has produced marked advances in the understanding of the pathophysiology of these conditions, with concomitant innovations in treatment. This article will highlight present and future perspectives relevant to these diseases, with a focus on an emerging approach utilizing disease-specific mutations to develop a novel taxonomy for these conditions.

Evolution of clinical and translational advances in the management of pediatric arteriovenous malformations

Arteriovenous malformations (AVMs) represent one of the most challenging diagnoses in pediatric neurosurgery. Until recently, the majority of AVMs was only identified after hemorrhage and primarily treated with surgery. However, recent advances in a wide range of fields-imaging, surgery, interventional radiology, radiation therapy, and molecular biology-have profoundly advanced the understanding and therapy of these complex lesions. Here we review the progress made in pediatric AVMs with a specific focus on innovations relevant to clinical care.

Endovascular Management of Brain Arteriovenous Malformations

Due to the risk of cerebral hemorrhage, and its related morbidity-mortality, brain arteriovenous malformations (bAVMs) are a rare and potentially life-threatening disease. Despite this, there is only one randomized controlled trial on bAVM management, A Randomized trial of Unruptured Brain Arteriovenous malformations (ARUBA). The results of the ARUBA trial favor a noninterventional approach in the case of an unruptured bAVM; however, implementation of these findings is challenging in daily practice. Instead, management of bAVM relies on multidisciplinary discussions that lead to patient-specific strategies based on patient preferences, local expertise, and experience in referral centers. Considering the diverse patterns of presentation and numerous treatment modalities, implementing standardized guidelines in this context proves challenging, notwithstanding the recommendations or expert opinions offered. Endovascular treatment (EVT) of bAVM can be curative, or can serve as an adjunct treatment prior to surgery or radiosurgery ("pre-EVT"). EVT practice is in constant evolution (i.e., venous approach, combination with surgery during the same anesthesia, etc.). Liquid embolic agents such as ethylene vinyl alcohol (EVOH) copolymer and cyanoacrylates (CYA), and their method of injection to increase bAVM occlusion have also benefited from technical evolutions such as the use of adjunctive flow arrest techniques (mini balloons, pressure cooker technique, and multiple catheters). Further research is necessary to evaluate the advantages and disadvantages of EVT for bAVM.

State of the Art in the Role of Endovascular Embolization in the Management of Brain Arteriovenous Malformations-A Systematic Review

As a significant cause of intracerebral hemorrhages, seizures, and neurological decline, brain arteriovenous malformations (bAVMs) are a rare group of complex vascular lesions with devastating implications for patients' quality of life. Although the concerted effort of the scientific community has improved our understanding of bAVM biology, the exact mechanism continues to be elucidated. Furthermore, to this day, due to the high heterogeneity of bAVMs as well as the lack of objective data brought by the lack of evaluative and comparative studies, there is no clear consensus on the treatment of this life-threatening and dynamic disease. As a consequence, patients often fall short of obtaining the optimal treatment. Endovascular embolization is an inherent part of multidisciplinary bAVM management that can be used in various clinical scenarios, each with different objectives. Well-trained neuro-interventional centers are proficient at curing bAVMs that are smaller than 3 cm; are located superficially in noneloquent areas; and have fewer, larger, and less tortuous feeding arteries. The transvenous approach is an emerging effective and safe technique that potentially offers a chance to cure previously untreatable bAVMs. This review provides the state of the art in all aspects of endovascular embolization in the management of bAVMs.

New aneurysm formation and regrowth associated with rebleeding of residual pediatric ruptured arteriovenous malformation: patient series

BACKGROUND

If complete obliteration of ruptured pediatric arteriovenous malformation (AVM) cannot be achieved, the appropriate follow-up duration and predictors of rebleeding remain unknown.

OBSERVATIONS

Pediatric patients with ruptured AVMs admitted to the authors' hospital within the past 30 years were evaluated. Rebleeding was confirmed in two patients. The first patient was a 5-year-old boy who experienced right thalamic hemorrhage. AVM was found in the bilateral thalamus and treated with stereotactic radiosurgery (SRS). New aneurysm formation and residual AVM regrowth were confirmed 21 years after the SRS. Eight months later, rebleeding occurred. The second patient was a 5-year-old boy who underwent removal of a left cerebellar hemorrhage and AVM. The residual AVM was treated with SRS. Residual AVM regrowth was detected at 6 years 7 months after SRS. Five months later, new aneurysm formation was confirmed. Two additional days later, rebleeding occurred.

LESSONS

New aneurysm formation and residual AVM regrowth may predict rebleeding and can occur >20 years after the initial rupture and treatment. If AVM obliteration is not achieved, long-term follow-up is needed, even in adulthood, with attention to new aneurysm formation and residual AVM regrowth. Further treatment is recommended if these findings are confirmed.

Endovascular treatment in the multimodality management of brain arteriovenous malformations: report of the Society of NeuroInterventional Surgery Standards and Guidelines Committee

BACKGROUND

The purpose of this review is to summarize the data available for the role of angiography and embolization in the comprehensive multidisciplinary management of brain arteriovenous malformations (AVMs METHODS: We performed a structured literature review for studies examining the indications, efficacy, and outcomes for patients undergoing endovascular therapy in the context of brain AVM management. We graded the quality of the evidence. Recommendations were arrived at through a consensus conference of the authors, then with additional input from the full Society of NeuroInterventional Surgery (SNIS) Standards and Guidelines Committee and the SNIS Board of Directors.

RESULTS

The multidisciplinary evaluation and treatment of brain AVMs continues to evolve. Recommendations include: (1) Digital subtraction catheter cerebral angiography (DSA)-including 2D, 3D, and reformatted cross-sectional views when appropriate-is recommended in the pre-treatment assessment of cerebral AVMs. (I, B-NR) . (2) It is recommended that endovascular embolization of cerebral arteriovenous malformations be performed in the context of a complete multidisciplinary treatment plan aiming for obliteration of the AVM and cure. (I, B-NR) . (3) Embolization of brain AVMs before surgical resection can be useful to reduce intraoperative blood loss, morbidity, and surgical complexity. (IIa, B-NR) . (4) The role of primary curative embolization of cerebral arteriovenous malformations is uncertain, particularly as compared with microsurgery and radiosurgery with or without adjunctive embolization. Further research is needed, particularly with regard to risk for AVM recurrence. (III equivocal, C-LD) . (5) Targeted embolization of high-risk features of ruptured brain AVMs may be considered to reduce the risk for recurrent hemorrhage. (IIb, C-LD) . (6) Palliative embolization may be useful to treat symptomatic AVMs in which curative therapy is otherwise not possible. (IIb, B-NR) . (7) The role of AVM embolization as an adjunct to radiosurgery is not well-established. Further research is needed. (III equivocal, C-LD) . (8) Imaging follow-up after apparent cure of brain AVMs is recommended to assess for recurrence. Although non-invasive imaging may be used for longitudinal follow-up, DSA remains the gold standard for residual or recurrent AVM detection in patients with concerning imaging and/or clinical findings. (I, C-LD) . (9) Improved national and international reporting of patients of all ages with brain AVMs, their treatments, side effects from treatment, and their long-term outcomes would enhance the ability to perform clinical trials and improve the rigor of research into this rare condition. (I, C-EO) .

CONCLUSIONS

Although the quality of evidence is lower than for more common conditions subjected to multiple randomized controlled trials, endovascular therapy has an important role in the management of brain AVMs. Prospective studies are needed to strengthen the data supporting these recommendations.

Single-center experience with endovascular treatment of cerebral arteriovenous malformations with intent to cure in pediatric patients

PURPOSE

This study aimed to report the incidence of technical complications and immediate complete angiographic occlusion, identify associated factors with failure of complete occlusion and identify predictors of technical complications in a single-center experience of pediatric arteriovenous malformations (AVM) treated with endovascular treatment with intent to cure.

METHODS

Patients between 1 and 18 years of age undergoing endovascular embolization between 2011 and 2020 were included.

RESULTS

A total of 120 embolizations were performed in 69 patients. The most frequent clinical presentation was intracerebral hemorrhage (76.8%). Immediate obliteration of the malformations was achieved in 40 (58%) cases. The technical complication rate was 15%. AVM nidus size between 3 and 6 cm (OR: 3.91; 95% CI 1.1-13.85; p = 0.035) and the presence of multiple feeders (OR: 5.08; 95% CI 1.41-18.28; p = 0.074) were predictive of failure of immediate complete occlusion. The location of the temporal lobe (OR: 7.83; p = 0.048), deep venous drainage (OR: 4.67; p = 0.112), and the presence of an intranidal aneurysm (OR: 3.58; p = 0.134) were predictors of technical complications.

CONCLUSIONS

Embolization of pediatric AVMs with intent to cure shows a high rate of technical complications and acceptable immediate occlusion rates. Nidus size and the presence of multiple feeders were predictive of failure of complete occlusion, while temporal lobe location, deep venous drainage, and the presence of an intranidal aneurysm were predictors of technical complications. Further studies are needed to determine the best therapeutic approach in the pediatric population.

Endovascular Treatment of Posterior Cerebral Artery Trunk Aneurysm: The Status Quo and Dilemma

The posterior cerebral artery (PCA) is an important artery that can be divided into four segments (P1-4): segments P1-2 are proximal segments, and segments P3-4 are distal segments. Various aneurysms can occur along the PCA trunk. True saccular aneurysms are rare, and most PCA trunk aneurysms are dissecting. Sometimes, the PCA trunk can give rise to flow-related aneurysms in association with high-flow arteriovenous shunt diseases or moyamoya disease and internal carotid artery occlusion. Some PCA trunk aneurysms require treatment, especially ruptured or large/giant aneurysms. Recently, endovascular treatment (EVT) has become the mainstream treatment for PCA trunk aneurysms, and it mainly involves reconstructive or deconstructive techniques. Traditional EVT includes selective coiling with/without stent or balloon assistance and parent artery occlusion (PAO). For proximal aneurysms, the PCA should be preserved. For distal aneurysms, PAO can be performed. However, during EVT, preservation of the PCA must naturally be the prime objective. Recently, flow-diverting stents have been used and are a revolutionary treatment for unruptured dissecting aneurysms of the PCA trunk. Despite the associated complications, EVT remains an effective method for treating PCA trunk aneurysms and can result in a good prognosis.

Longitudinal Changes in Size of Conservatively Managed Flow-Related Aneurysms Associated with Brain Arteriovenous Malformations

BACKGROUND

Flow aneurysms (FAs) associated with brain arteriovenous malformations (AVMs) are thought to arise from increased hemodynamic stress due to high-flow shunting. This study aims to describe the changes in conservatively managed FAs after successful AVM treatment.

METHODS

Patients with symptomatic AVMs and associated FAs who underwent successful treatment of the AVM between 2008 and 2017 were included. FA dimensions were measured on surveillance angiography to assess longitudinal changes.

RESULTS

Thirty-two patients were identified with 48 FAs. Sixteen (33%) FAs were treated endovascularly; 18 (38%) FAs were treated surgically; and 14 (29%) FAs (11 patients) were monitored. FAs demonstrated a decrease in size from 5.0 mm to 3.8 mm (24%; P = 0.016) and 4.9 mm to 3.6 mm (27%; P = 0.013) in height and width, respectively, over a median 35 months. However, on subgroup analysis, only class IIb aneurysms demonstrated a significant decrease in size (51% reduction in largest diameter, P = 0.046) and only 3 FAs (21%) resolved. There were no hemorrhages observed during follow-up.

CONCLUSIONS

While conservatively managed FAs demonstrated a reduction in size after the culprit AVM was treated, this was only significant in FAs located close to an AVM nidus (class IIb). There were no hemorrhages during the median 35 months' follow-up; however, long-term data are lacking. Our data support close observation of all conservatively managed aneurysms and a tailored approach based on the proximity to the nidus and observed changes in size.

Chinese Cerebrovascular Neurosurgery Society and Chinese Interventional & Hybrid Operation Society, of Chinese Stroke Association Clinical Practice Guidelines for Management of Brain Arteriovenous Malformations in Eloquent Areas

Aim: The aim of this guideline is to present current and comprehensive recommendations for the management of brain arteriovenous malformations (bAVMs) located in eloquent areas. Methods: An extended literature search on MEDLINE was performed between Jan 1970 and May 2020. Eloquence-related literature was further screened and interpreted in different subcategories of this guideline. The writing group discussed narrative text and recommendations through group meetings and online video conferences. Recommendations followed the Applying Classification of Recommendations and Level of Evidence proposed by the American Heart Association/American Stroke Association. Prerelease review of the draft guideline was performed by four expert peer reviewers and by the members of Chinese Stroke Association. Results: In total, 809 out of 2,493 publications were identified to be related to eloquent structure or neurological functions of bAVMs. Three-hundred and forty-one publications were comprehensively interpreted and cited by this guideline. Evidence-based guidelines were presented for the clinical evaluation and treatment of bAVMs with eloquence involved. Topics focused on neuroanatomy of activated eloquent structure, functional neuroimaging, neurological assessment, indication, and recommendations of different therapeutic managements. Fifty-nine recommendations were summarized, including 20 in Class I, 30 in Class IIa, 9 in Class IIb, and 2 in Class III. Conclusions: The management of eloquent bAVMs remains challenging. With the evolutionary understanding of eloquent areas, the guideline highlights the assessment of eloquent bAVMs, and a strategy for decision-making in the management of eloquent bAVMs.

Arteriovenous malformation with associated multiple flow-related distal anterior cerebral artery aneurysms: A case report with poor outcomes

Background

Low-grade arteriovenous malformations (AVMs) associated with multiple flow-related distal anterior cerebral artery (DACA) aneurysms are rare occurrences. Here, we present a case of a frontal AVM with three associated DACA aneurysms arising from a single feeder.

Case Description

A 36-year-old male presented to us in the ER with acute-onset dysphasia and altered mental status. Head computed tomography and angiogram showed a spontaneous intracerebral hemorrhage with intraventricular extension and revealed a Spetzler Martin Grade II AVM, being fed by two feeders, with the major feeder from the DACA bearing three flow-related aneurysms. As the patient awaited digital subtraction angiography, his Glasgow Coma Scale dropped and he underwent emergency embolization with Onyx. This was followed by external ventricular drainage. The patient's neurological status did not improve, and he died following a complicated clinical course.

Conclusion

Multiple DACA aneurysms are a case of both clinical and anatomical rarity and to avoid complications in the clinical course, one must be judicious about the time spent between symptom onset and embolization.

Acute Subdural Hematomas in Ruptured Brain Arteriovenous Malformations: Association with Distal Flow-Related Aneurysms

PURPOSE

Non-traumatic acute subdural hematomas (SDH) are rare and have seldom been reported in ruptured brain arteriovenous malformations (BAVM). The aim of this study was to report the frequency of acute SDH in BAVM-related hemorrhage and to determine the relationship of SDHs with BAVM angioarchitectural features.

METHODS

This was a retrospective monocentric study of patients admitted for BAVM rupture between 2003 and 2017. Patients with rupture complicating or closely following partial embolization procedures were excluded. Univariate followed by multivariate logistic regression analysis was used to determine factors significantly and independently associated with SDHs and distal flow-related aneurysms.

RESULTS

A total of 181 patients with 188 BAVM ruptures admitted during the study period were included, eleven cases of acute SDH were identified (6%) and 2 cases of isolated SDH were found. The presence of a distal flow-related aneurysm was the only feature independently and significantly associated with SDH (odds ratio [OR] 8.1, 95% confidence interval, CI 1.9-34.5, P = 0.003). Distal flow-related aneurysms were associated with proximal flow-related aneurysms (OR 28, 95%CI 4.9-163.8, P < 0.001), were more frequent in infratentorial BAVMs (OR 3.7, 95%CI 1.3-10.2, P = 0.01) and more often found in cases of acute SDH (OR 16.9, 95%CI 3.6-79.6, P < 0.001) and subarachnoid hemorrhage (SAH) (OR 4.5, 95%CI 1.7-12.2, P = 0.003).

CONCLUSION

Ruptured BAVMs can rarely present with acute SDH and SDH in ruptured BAVMs are often associated with distal flow-related aneurysms. This finding may impact acute management of ruptured BAVMs with SDH by eliciting an emergent and thorough imaging work-up to identify distal flow-related aneurysm(s), in turn leading to treatment.

Timing of surgery for ruptured supratentorial arteriovenous malformations

BACKGROUND

There are conflicting opinions regarding the optimal waiting time to perform surgery after rupture of supratentorial arteriovenous malformations (AVMs) to achieve the best possible outcome.

OBJECTIVE

To analyze factors influencing outcomes for ruptured supratentorial AVMs after surgery, paying particular attention to the timing of the surgery.

METHODS

We retrospectively investigated 59 patients admitted to our center between 2000 and 2014 for surgical treatment of ruptured supratentorial AVMs. We evaluated the effect of timing of surgery and other variables on the outcome at 2-4 months (early outcome), at 12 months (intermediate outcome) after surgery, and at final follow-up at the end of 2016 (late outcome).

RESULTS

Age over 40 years (OR 18.4; 95% CI 1.9-172.1; p = 0.011), high Hunt and Hess grade (4 or 5) before surgery (OR 13.5; 95% CI 2.1-89.2; p = 0.007), hydrocephalus on admission (OR 12.9; 95% CI 1.8-94.4; p = 0.011), and over 400 cm³ bleeding during surgery (OR 11.5; 95% CI 1.5-86.6; p = 0.017) were associated with an unfavorable early outcome. Age over 40 years (OR 62.8; 95% CI 2.6-1524.9; p = 0.011), associated aneurysms (OR 34.7; 95% CI 1.4-829.9; p = 0.029), high Hunt and Hess grade before surgery (OR 29.2; 95% CI 2.6-332.6; p = 0.007), and over 400 cm³ bleeding during surgery (OR 35.3; 95% CI 1.7-748.7; p = 0.022) were associated with an unfavorable intermediate outcome. Associated aneurysms (OR 8.2; 95% CI 1.2-55.7; p = 0.031), high Hunt and Hess grade before surgery (OR 5.7; 95% CI 1.3-24.3; p = 0.019), and over 400 cm³ bleeding during surgery (OR 5.8; 95% CI 1.2-27.3; p = 0.027) were associated with an unfavorable outcome at last follow-up. Elapsed time between rupture and surgery did not affect early or final outcome.

CONCLUSIONS

Early surgery in patients with ruptured supratentorial arteriovenous malformation is feasible strategy, with late results comparable to those achieved with delayed surgery. Many other factors than timing of surgery play significant roles in long-term outcomes for surgically treated ruptured supratentorial AVMs.

Early Rebleeding after Brain Arteriovenous Malformation Rupture, Clinical Impact and Predictive Factors: A Monocentric Retrospective Cohort Study

Background: Brain arteriovenous malformations (BAVMs) are a leading cause of intracranial hemorrhage in young adults. This study aimed to identify individual predictive factors of early rebleeding after BAVM rupture and determine its impact on prognosis. Methods: Early rebleeding was defined as a spontaneous intracranial hemorrhage within 30 days of BAVM rupture in patients with nonobliterated BAVMs. One hundred fifty one patients with 158 BAVM hemorrhagic events admitted to a tertiary care center during 14 years were included. Univariate followed by multivariate logistic regression was performed to assess the impact of early rebleeding on in-hospital mortality and modified Rankin Scale (mRS) score beyond 3 months and to identify independent predictors of early rebleeding. Results: Eight early rebleeding events were observed, 6 of which occurred during the first 7 days. Early rebleeding was independently and significantly associated with poor outcome (mRS ≥3 beyond 3 months, p = 0.004) but not with in-hospital mortality (p = 0.9). Distal flow-related aneurysms (p = 0.009) and altered consciousness with a Glasgow coma scale score of 3 (p = 0.01) were independently associated with early rebleeding. Conclusions: Early rebleeding is a severe complication that can occur after BAVM-related hemorrhage. Distal flow-related aneurysms and initial altered consciousness are associated with early rebleeding.

Grade 1 Spetzler and Martin cerebral ruptured arteriovenous malformations treated by microsurgery: Poor functional outcome is related to injury from haemorrhage

INTRODUCTION

Ruptured arteriovenous malformations (rAVM) are life-threatening diseases.

OBJECTIVE

To evaluate the outcome of patients with grade 1 SPM rAVM after microsurgical treatment.

MATERIALS AND METHOD

We retrospectively included 64 consecutive operated patients with a grade 1 SPM rAVM in our institution between 2002 and 2012. Complications related to the surgical procedure were recorded. All patients were re-evaluated 3months after treatment using the modified Rankin Scale score (mRS). Persistent neurological disorders were evaluated 1year after bleeding. Conventional cerebral angiography was performed for each patient immediately after surgical treatment and 1year later.

RESULTS

The mean age at diagnosis was 30.8 years. Initial WFNS score was grade 1 in 25 patients, grade 2 in 11 patients, grade 3 in 10 patients, grade 4 in 9 patients and grade 5 in 9 patients. No remnant was left and a new surgery was performed only in a single patient who was initially operated-on under emergency conditions with limited preoperative investigations due to a poor clinical grade. Early postoperative complications related to the surgical procedure were recorded in 7 patients. The mRS score 3months after treatment was ≤2 in 53 patients (83%). Persistent neurological disorders were recorded in 40 patients (62.5%). High initial WFNS score (>2) and the hydrocephalus were significantly associated (P<0.05) to a bad functional outcome (mRS>2).

CONCLUSION

Grade 1 rAVM is a life-threatening disease concerning in most cases young patients. Long-term morbidity is often related to the hemorrhagic brain damage and rarely to the AVM resection.

Target Embolization of Associated Aneurysms in Ruptured Arteriovenous Malformations

OBJECTIVES

The purpose of this study was to examine the safety and efficacy of target embolization of aneurysms associated with ruptured brain arteriovenous malformations (BAVMs).

METHODS

Ruptured BAVM patients who underwent endovascular treatment at our institution from January 2011 to December 2015 were retrospectively reviewed. Patients were divided into aneurysm (AN) and nonaneurysm (non-AN) groups on the basis of the existence of BAVM-associated aneurysms or not. Demographics, angiographic characteristics, complications, and clinical outcomes were compared between 2 groups. Complication risk factors were analyzed for all objects. Patient outcomes were assessed with modified Rankin Scale (mRS).

RESULTS

A total of 129 (male = 53) patients were included. In 31 (24.0%) patients, 33 aneurysms were observed, including 16 intranidal and 17 flow-related aneurysms. Of the 166 sessions of embolization performed, there were 13 (10.1% of patients, 7.8% per session) complications in all, including 2 hemorrhagic, 8 transient ischemic, and 3 permanent ischemic types. There was no statistical difference in terms of complication incidence rate between groups. A total of 12 patients (9.3% of patients, 3.3% per person-year) experienced postoperative hemorrhage during follow-up (mean = 3.4 years). The yearly postoperative hemorrhage incidence rate was 3.4% in the non-AN group and 2.0% in AN group. Excellent or good outcomes (mRS ≤ 2) were observed in 103 (91.2%) patients. Unfavorable outcomes (mRS ≥ 3) as a direct result of embolization remained in no patients.

CONCLUSIONS

Target embolization of aneurysms associated with ruptured BAVMs could significantly decrease postoperative rehemorrhage without increasing complications.

Arterial aneurysms associated with arteriovenous malformations of the brain: classification, incidence, risk of hemorrhage, and treatment-a systematic review

BACKGROUND

Aneurysms associated with brain arteriovenous malformations (bAVMs) influence the natural history of these lesions and pose important therapeutic challenges. However, the epidemiology, natural history, and appropriate management of the aneurysms associated with bAVMs are not completely understood due to the paucity of large and uniform studies. We performed a systematic review of published series examining the association between aneurysms and bAVMs with the purpose of clarifying the prevalence, risk of hemorrhage, and appropriate management of these lesions.

METHOD

PRISMA/MOOSE guidelines were followed. We conducted a comprehensive literature search of three databases (PubMed, Ovid MEDLINE, and Ovid EMBASE) on aneurysms associated with bAVMs. Only studies examining consecutive case series of aneurysms associated with bAVMs were included. From the collected studies, we extracted data regarding prevalence of bAVM-associated aneurysms, risk of aneurysm rupture in relation to bAVM location and aneurysm characteristics, and treatment-related outcomes.

RESULTS

Our systematic review included 44 articles with a total of 10,093 bAVMs. The proportion of bAVMs with an associated aneurysm was 20.2 % (95 % CI = 19.4-20.9 %). Among ruptured bAVMs with associated aneurysms, the aneurysm was the source of hemorrhage in 49.2 % (95 % CI = 43.7-54.7 %) of cases. Flow-related aneurysms were the most common source of aneurysm rupture (78.5 %, 95 % CI = 70.6-84.9 %). Infratentorial bAVM-associated aneurysms presented a higher risk of rupture (60 %, 95 % CI = 47.4-71.9 %) when compared with supratentorial lesions (29 %, 95 % CI = 21.4-38.5 %). Endovascular treatment of aneurysms associated with bAVMs had a cure rate of 80.0 % (95 % CI = 73.3-85.3 %), complication rate of 8.7 % (95 % CI = 5.5-13.1 %), and a good neurological outcome rate of 78.8 % (95 % CI = 72.5-83.9 %).

CONCLUSIONS

Twenty percent of bAVMs harbored arterial aneurysms. The presence of aneurysm increases the risk of bleeding of the bAVM, especially when flow-related or infratentorially located. Aneurysms associated with bAVMs should be treated promptly. Selective endovascular treatment of bAVM-associated aneurysms appears safe and effective.

Clinical characteristics of arteriovenous malformations in the cerebellopontine angle cistern

OBJECTIVE Arteriovenous malformations (AVMs) in the cerebellopontine angle cistern (CPAC) are specific lesions that can cause neurovascular compression syndromes as well as intracranial hemorrhage. Although case reports describing the CPAC AVMs, especially those presenting with trigeminal neuralgia (TN), have been accumulating by degrees, the pathophysiology of CPAC AVMs remains obscure. The authors' purpose in the present study was to evaluate the clinical and radiographic features of CPAC AVMs as well as the treatment options. METHODS This study defined a CPAC AVM as a small AVM predominantly located in the CPAC with minimal extension into the pial surface of the brainstem and closely associated with cranial nerves. All patients with CPAC AVMs treated in the authors' affiliated hospitals over a 16-year period were retrospectively identified. Clinical charts, imaging studies, and treatment options were evaluated. RESULTS Ten patients (6 men and 4 women), ranging in age from 56 to 77 years (mean 65.6 years), were diagnosed with CPAC AVMs according to the authors' definition. Six patients presented with hemorrhage, 3 with TN, and the remaining patient developed a hemorrhage subsequent to TN. Seven AVMs were associated with the trigeminal nerve (Group V), and 3 with the facial-vestibulocochlear nerve complex (Group VII-VIII). All patients in Group VII-VIII presented with the hemorrhage instead of hemifacial spasm. Regarding angioarchitecture, the intrinsic pontine arteries provided the blood supply for all CPAC AVMs in Group V. In addition, 5 of 7 AVMs with hemorrhagic episodes accompanied flow-related aneurysms, although no aneurysm was detected in patients with TN alone. With respect to treatment, all patients with hemorrhagic presentation underwent Gamma Knife surgery (GKS), resulting in favorable outcomes except for 1 patient who experienced rebleeding after GKS, which was caused by the repeated rupture of a feeder aneurysm. The AVMs causing TN were managed with surgery, GKS, or a combination, according to the nidus-nerve relationship. All patients eventually obtained pain relief. CONCLUSIONS Clinical symptoms caused by CPAC AVMs occur at an older age compared with AVMs in other locations; CPAC AVMs also have distinctive angioarchitectures according to their location in the CPAC. Although GKS is likely to be an effective treatment option for the CPAC AVMs with hemorrhagic presentations, it seems ideal to obliterate the flow-related aneurysms before performing GKS, although this is frequently challenging. For CPAC AVMs with TN, it is important to evaluate the nidus-nerve relationship before treatment, and GKS is especially useful for patients who do not require urgent pain relief.

Increased prevalence and rupture status of feeder vessel aneurysms in posterior fossa arteriovenous malformations

Background

Posterior fossa arteriovenous malformations (AVMs) are considered to have a higher risk of poor outcome, as are AVMs with associated aneurysms. We postulated that posterior fossa malformations may be more prone to associated feeder vessel aneurysms, and to aneurysmal source of hemorrhage.

Objective

To examine the prevalence and hemorrhagic risk of posterior fossa AVM-associated feeder vessel aneurysms.

Methods

A retrospective review of AVMs was performed with attention paid to location and presence of aneurysms. The hemorrhage status and origin of the hemorrhage was also reviewed.

Results

571 AVMs were analyzed. Of 90 posterior fossa AVMs, 34 (37.8%) had aneurysms (85% feeder vessel, 9% intranidal, 15% with both). Of the 481 supratentorial AVMs, 126 (26.2%) harbored aneurysms (65% feeder vessel, 29% intranidal, 6% both). The overall incidence of feeder aneurysms was higher in posterior fossa AVMs, which were evident in 34.4% of infratentorial AVMs compared to 18.5% of supratentorial malformations (p<0.01). The presence of intranidal aneurysms was similar in both groups (9.2% vs 8.8%). Feeder artery aneurysms were much more likely to be the source of hemorrhage in posterior fossa AVMs than in supratentorial AVMs (30% vs 7.6%, p<0.01).

Conclusions

Posterior fossa AVMs are more prone to developing associated aneurysms, specifically feeder vessel aneurysms. Feeder vessel aneurysms are more likely to be the source of hemorrhage in the posterior fossa. As such, they may be the most appropriate targets for initial and prompt control by embolization or surgery due to their elevated threat.