Occlusion Of Arteriovenous Malformations Research Articles

An Algorithm for the Multimodality Treatment of Cerebral Arteriovenous Malformations

Abstract Introduction: The algorithm of multimodal treatment (MMT) of arteriovenous malformations (AVMs) combined with intent-to-cure and presurgery embolization benefits was developed. The aim was to analyze the effectiveness of the MMT compared with unimodal intent-to-cure embolization in patient groups matched concerning clinical and angiographic characteristics. Methods: A prospective cohort study of MMT effectiveness and safety was performed. To estimate differences in the total occlusion rate and complication rate of MMT compared to unimodal embolization, a 1:1 matched patient group was identified from the Russian Endovascular Neuro Society (RENS) AVM registry using the propensity score matching (EMB group). The treatment outcomes were assessed by the rate of achieving 100% AVM obliteration on follow-up angiography, morbidity, mortality, and the perioperative complication rate. Results: Complete AVM occlusion was achieved in 93.7% of patients in the MMT group vs 76.2% of patients in the EMB group (p < 0.001). A favorable clinical outcome (mRS = 0–1 at the end of follow-up) was observed in significantly more patients in the MMT group compared with the EMB group (88.9% vs 71.4%, p = 0.024). In the MMT group, the rates of intraoperative and postoperative ischemic complications were comparable to those in the EMB group, and there was a significantly lower rate of postoperative hemorrhagic complications (6.3% vs 20.6%, p = 0.035). Conclusions: Embolization as the main curative technique of the multimodal algorithm timely followed by microsurgery and radiosurgery ensures the highest clinical and angiographic efficacy of treatment and reduces the rate of disabling postoperative complications.

Hemodynamic changes of arteriovenous malformation and endovascular embolization.

Objective: To analyze the hemodynamic changes caused by arteriovenous malformation (AVM) and AVM embolization through a meta-analysis of the existing literature. Method: Search for relevant studies on PubMed/Medline until November 7, 2023, and further screen the bibliographies of relevant studies to ensure comprehensive search. According to the PRISMA guidelines, manuscripts were selected to provide local hemodynamic information on AVM arterial feeders and drainage veins. Result: A total of 13 studies were included in the final analysis. The diameter of the supplying artery (y = 0.002x + 2.24, R2 = 0.99) and flow velocity (y = 0.09x + 54.55, R2 = 0.92) had a positive linear relationship with cerebral blood flow. The pressure difference through the small AVM nidus was higher than that in the large AVM, with values of (y = -12.23x + 101.39, R2 = 0.96). There was a negative linear correlation between the sessions of AVM embolization and blood flow (1 session: y = -150.7x + 564.97, R2 = 0.98 and 4 sessions: y = -118.81x + 750.07, R2 = 0.99). There was a positive linear relationship between the increase in arterial pressure, peri-AVM parenchymal perfusion, and the percentage of occlusion in the medium-sized AVMs. However, this correlation was a nonlinear relationship between elevated arterial pressure, peri-AVM parenchymal perfusion, and the percentage of large AVM occlusion. Conclusion: The hemodynamic changes of AVM (in the feeding arteries, compartments of AVM, and draining veins) follow a linear relationship. The impact of embolization on hemodynamics in medium and small AVMs follows a linear relationship. The impact of embolization of large AVMs on hemodynamics follows a nonlinear relationship.

Efficacy and safety of endovascular embolization of cerebral AVM

Background; Endovascular embolization of cerebral arteriovenous malformations (AVM) has several benifits including AVM occlusion and flow reduction in preparation for other treatment techniques. Aim and objectives; To assess the efficacy and safety of endovascular embolization of cerebral AVM with different techniques and materials. Patients and methods; In a prospective and retrospective study, 22 patients diagnosed as AVM or arteriovenous fistula (AVF) and underwent endovascular embolization at Neurosurgical intervention Unit at Al Hussein University Hospital were recruited in the period from beginning of Jan, 2020 to the end of May, 2022. We included patients aged above one month, diagnosed to have cerebral AVM or AVF. Recent cerebral hemorrhage patients were delayed for at least two weeks. We excluded patients with vein of Galen malformation, neonatal AVM, patients underwent surgical excision, patients with contraindication to radiation or dye injection, and inaccessible endovascular techniques such as severely tortuous vessels. Results: In the current study, the mean age was 24.5 ± 14.7 years. Most cases were male (68.2%). Most cases (86.4% ) manifested headache, 40.9% had hemorrhage, 31.8% had side weakness and 27.3% had fits. Spetzler and Martin grade (SMG) of the cerebral AVMs was significantly improved after embolization compared to the initial grading score (P=0.002). Eight patients showed complete occlusion of nidus and 14 had partial occlusion according to SMG . After 3 months follow up, Modified Rankin scale, epilepsy, and headache were improved. No patient had procedure-related complications.

Spontaneous occlusion of the cerebral arteriovenous malformations

Spontaneous occlusion of arteriovenous malformations (AVM), characterized by complete disappearance of the AVM nidus and early venous drainage, and is a rare. The frequency of this phenomenon varied from 0.1 to 1.3 %.We analyzed two cases of spontaneous occlusion of cerebral AVMs with a non-hemorrhagic debut after 3 and 13 years in women aged 28 and 40 years, respectively. In both cases AVM was diagnosed during routine neuroimaging because of headache. Both patients had superficial small malformations. After discussing the risks of surgical treatment, both patients refused to perform any intervention. Scheduled angiography was performed 3 years after the diagnosis to follow-up the course of the disease and revealed complete disappearance of the AVM. Another patient noted persistent regression of headache after 3 years. Follow-up angiography was performed 13 years after diagnosis and confirmed spontaneous occlusion of the AVM. Given the data on the recurrence of the disease after spontaneous occlusion, such patients require long-term follow-up.When an AVM ruptures, hemodynamic changes may explain the thrombosis of the malformation, but the mechanisms of spontaneous occlusion in non-ruptured AVM remain unclear.

Rotational angiography and the contribution of roadmapping to the occlusion of arteriovenous malformations

Rotational angiography and the contribution of roadmapping to the occlusion of arteriovenous malformations

Rotational angiography and the contribution of roadmapping to the occlusion of arteriovenous malformations. How would I approach it?

Rotational angiography and the contribution of roadmapping to the occlusion of arteriovenous malformations. How would I approach it?

Rotational angiography and the contribution of roadmapping to the occlusion of arteriovenous malformations. Case resolution

Rotational angiography and the contribution of roadmapping to the occlusion of arteriovenous malformations. Case resolution

The transvenous retrograde pressure cooker technique for the curative embolization of high-grade brain arteriovenous malformations

BackgroundTransvenous embolization of brain arteriovenous malformations (AVMs) can be curative. We aimed to evaluate the cure rate and safety of the transvenous retrograde pressure cooker technique (RPCT) using coils and...

A rare case report of extensive abdominopelvic endometriosis mimicking peritoneal malignancy: an imaging investigation

Introduction: Endometriosis is a benign condition characterized by endometrial tissue deposited outside the uterine cavity. Endometriosis characteristics include a well-defined cyst (endometrioma) with or without internal septations and seeding nodules; however, no case of extensive infiltrating abdominopelvic endometriosis have been reported.Case presentation: A 48-year-old female presented with incidentally found a hypervascular lesion in the pelvic cavity from routine checkup ultrasound. The computed tomography (CT) angiography investigation showed pelvic arteriovenous malformation (AVM). She underwent embolization at interventional radiology unit and the CT angiography follow up showed complete occlusion of pelvic AVM. However, eight months after embolization, she came with severe abdominal pain and hypotension. Emergency CT showed a large abdominopelvic mass with hemoperitoneum which was suspected for gynecologic or peritoneal malignancy. Further magnetic resonance image (MRI) was highly suspicious of peritoneum or mesentery malignancy. Surgical tumor removal was performed. The histologic results were negative for malignancy and the tumor was compatible with endometriosis.Conclusion: Extensive abdominopelvic endometriosis is rare, and its imaging findings may not exclude peritoneal malignancy. Therefore, a definite diagnosis via histological investigation is necessary.Â

The experience of simultaneous endovascular occlusion of arteriovenous malformation and saccular aneurism in a parturient woman

The clinical case of simultaneous endovascular bloodstream exclusion of arteriovenous malformation and saccular aneurysm in parturient woman is presented. Onyx liquid adhesive composition and monospiral aneurysm occlusion technique were used. Patient X., 31, was hospitalized to the clinic on the 10th day of the postpartum period. From the anamnesis: twice (at 20th and 27th weeks of pregnancy) patient suffered intraventricular hemorrhage due to the rupture of arteriovenous malformation in the posterior third of the corpus callosum, left lateral ventricle and left parietal lobe of the brain. After the first hemorrhage a conservative treatment tactic was determined, given the high risk of complications associated with the surgical intervention for the mother and fetus. After the second hemorrhage endovascular embolization of malformation was suggested, however, the patient and her husband refused surgery, preferring conservative therapy with subsequent surgical treatment after delivery. In addition to the malformation, according to the data of selective cerebral subtraction angiography multiple cerebral saccular aneurysms of the left Anterior Cerebral – Anterior Communicating Artery and 2 Anterior Cerebral Artery aneurysms (A2-A2, A3-A4-segments) on the right side were diagnosed. Endovascular subtotal embolization of arteriovenous malformation and occlusion of the right Anterior Cerebral Artery (A2-A3-segment) saccular aneurysm were performed during the operation. A control angiographic examination after 3 months showed a complete exclusion of these arteriovenous malformation and saccular aneurysm and disappearance of all aneurysms of the left Anterior Cerebral Artery – Anterior Communicating Artery and right Anterior Cerebral Artery (A3-A4-segment).

Occlusion of Animal Model Arteriovenous Malformations Using Vascular Targeting.

Brain arteriovenous malformations (AVMs) are a significant cause of intracerebral hemorrhage in children and young adults. Currently, one third of patients have no viable treatment options. Vascular targeting agents (VTAs) are being designed to deliver pro-thrombotic molecules to the abnormal AVM vessels for rapid occlusion and cure. This study assessed the efficacy of a pro-thrombotic VTA targeting phosphatidylserine (PS) in a radiation-primed AVM animal model. The model AVM was surgically created in rats by anastomosis of the left external jugular vein to the adjacent common carotid artery. After 6weeks, the AVM was irradiated (20Gy) using gamma knife surgery (GKS). A PS-targeting VTA was created by conjugation of annexin V with human thrombin and administered intravenously 3weeks post-GKS or sham. Unconjugated thrombin was used as a non-targeting control. AVM thrombosis and occlusion was monitored 3weeks later by angiography and histology. Preliminary experiments established a safe dose of active thrombin for systemic administration. Subsequently, a single dose of annexin V-thrombin conjugate (0.77mg/kg) resulted in angiographic AVM occlusion in sham (75%) and irradiated (63%) animals, while non-targeted thrombin did not. Lowering the conjugate dose (0.38mg/kg) decreased angiographic AVM occlusion in sham (13%) relative to irradiated (80%) animals (p= 0.03) as did delivery of two consecutive doses of 0.38mg/kg, 2days apart (sham (0%); irradiated (78%); p= 0.003). These findings demonstrate efficacy of the PS-targeting VTA and the feasibility of a vascular targeting approach for occlusion of high-flow AVMs. Targeting specificity can be enhanced by radiation-sensitization and VTA dose modification.

Endovascular therapy of arteriovenous malformation in a male patient with severe post-coital pelvic pain

PurposeCongenital pelvic arteriovenous malformations (AVMs) are high-flow vascular lesions consisting of abnormal shunts between arteries and veins within a nidus. The rare presentation and extensive network of vasculature contributes to the difficulty in effective treatment. Optimal therapeutic options are determined based on the clinical presentation, the location of the lesion, and possible complications.Case reportA 24-year-old male patient with a history of recurrent pain following sexual intercourse presented with complaints of intense pelvic pain radiating to the perineal area. Computed tomography angiography (CTA) revealed a large venous aneurysm as an outflow vein of a right-sided pelvic AVM. Embolisation of the outflow veins was established along with direct percutaneous delivery of fibre coils and thrombin to the venous aneurysm of the AVM. With recurring symptoms and AVM recanalisation on angiography, another direct puncture and placement of pushable coils was made. Total AVM occlusion was achieved with no recanalisation on follow-up digital subtraction angiography (DSA), and the patient remained asymptomatic.ConclusionsEndovascular embolisation of the nidus area may result in a complete occlusion of an AVM. Therefore, a thorough understanding of the vascular anatomy of the AVM is essential in choosing an effective embolisation strategy and to minimise the risk of possible complications.

Conus Medullaris Arteriovenous Malformation Presenting with Acute Dysphagia and Intractable Hiccups

Conus medullaris arteriovenous malformations (AVMs) are rare spinal vascular malformations presenting most frequently with features of myelopathy (Foix-Alajounine syndrome), radiculopathy, bowel/bladder dysfunction, or acute spinal hemorrhage (Coup de poignard of Michon) causing profound neurological deficit. Here we present the case of a young patient with progressive dysphagia and intractable hiccups as a rare first presentation symptom of later verified conus medullaris AVM. A 21-year-old male patient presented with acute onset of dysphagia and persistent hiccups. His magnetic resonance imaging of the spine demonstrated a lesion at the T11 and T12 levels with an associated holocord syrinx and syringobulbia to the level of the medulla. The patient underwent a decompressive suboccipital craniectomy and C1 (atlas) laminectomy with wide myelotomy of the medulla followed by T11 and T12 laminectomy and AVM reduction. Two days after partial AVM occlusion the patient developed transient worsening of his symptoms. Repeat magnetic resonance imaging showed recurrence of dilatation of the central canal. A syringo-subarachnoid shunt was sited at the level of the previous myelotomy of the medulla, after which his neurological symptoms resolved completely. This is the first case report in the English literature to date of a conus AVM presenting with intractable hiccups. These are extremely rare sporadic vascular malformations, and although their natural history is poorly understood, symptomatic patients generally deteriorate, culminating in severe disability. Management requires a multimodality approach including combined endovascular and microsurgical treatment. The patient in our case made a full recovery confirmed at 2-year follow-up.

Effectiveness of Preradiosurgical Embolization with NBCA for Arteriovenous Malformations - Retrospective Outcome Analysis in a Japanese Registry of 73 Patients (J-REAL study).

PurposeRecent reports have posed doubts about the effect of preradiosurgical embolization in brain arteriovenous malformation (AVM) because it makes the planning of stereotactic radiosurgery (SRS) difficult and has the risk of recanalization out of the target. We investigated whether the performance and quality of embolization may influence the success of SRS based on a retrospective case cohort study.Materials and MethodsSeventy-three patients who underwent embolization followed by SRS between 2003 and 2012 in eight institutes with neurointerventionists were considered. They were divided into the following two groups at 3 years of follow up after the final SRS: “successful occlusion group” (S group), with radiologically complete occlusion of AVM; and “non-successful occlusion group” (N group) with persistent remnant nidus or abnormal vascular networks. Patient background, AVM profile, embolization performance grade and complications were compared in each group. The quality of embolization was evaluated with the new grading system: embolization performance grade (E grade), specializing the achievement of nidus embolization. E grade A was defined as sufficient nidus embolization with more than half of the total number of feeders achieving nidus penetration. E grade B was defined as less than half achievement of nidus embolization, and E grade C was defines as failure to perform nidus embolization.ResultsForty-three patients were included in the S group, and 29 patients were included in the N group. The size and Spetzler-Martin grade of AVM and the rate of diffuse type was higher in the N group without statistical significance. The embolization performance level according to E grade indicated a significantly higher rate of successful embolization with more than 50% of nidus penetration in the S group (P<0.001). This difference was also confirmed in the subanalysis for limited cases, excluding smaller AVMs with complete occlusion with SRS alone (P=0.001).ConclusionThe cause of the unsuccessful result of post-embolization SRS might be the large, diffuse angioarchitecture, but proper embolization with a high rate of nidus penetration to avoid recanalization is more important. Effective embolization is essential to contribute to and promote the effect of radiosurgery.

Treatment of Cerebral Arteriovenous Malformations with Radiosurgery or Hypofractionated Stereotactic Radiotherapy in a Consecutive Pooled Linear Accelerator Series

To review outcomes after linear accelerator stereotactic radiosurgery (SRS) and hypofractionated stereotactic radiotherapy (hfSRT) of arteriovenous malformations (AVMs) from a consecutive and pooled series of 2 Novalis centers and to analyze the influence of AVM size, Spetzler-Martin (SM) grade, pretreatment, and hemorrhagic versus nonhemorrhagic presentation. A subgroup analysis of A Randomized Trial of Unruptured Brain Arteriovenous Malformations (ARUBA)-eligible patients also was performed. Prospectively collected treatment and outcome data were supplemented by retrospectively collected follow-up data for 93.8% of all patients. A total of 129 patients with AVM had SRS or hfSRT between 2000 and 2014 with the same linear accelerator system in 2 centers. Data analysis included initial presentation, SM grade, occlusion rates assessed by magnetic resonance and/or digital subtraction angiography, neurologic and therapeutic complications, and pretreatments. Statistical analysis was performed for patient demographic data and for factors potentially influencing outcome. Initial presentation was hemorrhage in 43.8% or seizures/neurologic deficits in 46.2%. The series included 6 SM grade I (5%), 26 SM II (21.5%), 55 SM III (45.5%), 28 SM IV (23%), and 6 SM V cases (5%). Pre-embolization was used in 36 patients (29.8%), 8 patients had previous surgery (6.6%), and 6 patients were irradiated before elsewhere (5%); 5 patients (4.2%) received multimodal pretreatment. Mean follow-up was 43 months. The occlusion rate for the total series was 71.1%, for SM I/II cases 80.6%, and 67.4% for the SM ≥ subgroup. The occlusion rate was 75.0% for the small volume (<4 cc) and 55.6% for the large volume (>10 cc) subgroup. There was no statistical difference between the occlusion rate of patients with or without pretreatment if taken all modalities together (72.7% and 69.7%, respectively). There was only a trend of a belated occlusion of pre-embolized AVMs. The occlusion rate for hemorrhagic AVM was with 77.4% better than for nonhemorrhagic (66.2%) or ARUBA-eligible AVMs (64.8%) but without reaching statistical significance. Neurologic deterioration was seen in 13.2% of the patients. There were 2 re-bleedings within 17-18 months (1.7%), 1 of them without a new neurologic deficit and total occlusion after re-SRS. One patient with pre-existing epilepsy died a sudden unexpected death (mortality rate: 0.8%). Overall SRS and hfSRT are valuable therapy options, especially in symptomatic patients with AVM, with a low rate of morbidity and mortality and an acceptable overall complete occlusion rate of >70% and >80% for SM I/II AVMs.

Curative embolization of pediatric intracranial arteriovenous malformations using Onyx: the role of new embolization techniques on patient outcomes.

Intracranial arteriovenous malformations (AVMs) are the most frequent cause of hemorrhagic strokes in the pediatric population. The study aim was to retrospectively assess the safety and efficacy of Onyx embolization with the intention to cure AVMs in a pediatric population. A retrospective analysis of all patients (<18years) who underwent endovascular embolization using Onyx at our institution was conducted. The primary endpoint was the composite complete angiographic occlusion of AVM immediately after the last embolization session that had no procedure-related complication requiring emergency surgery. Secondary endpoints were angiographic occlusion rates, procedure-related complications, and clinical outcomes after treatment and at the 6-month follow-up Twenty-three patients (mean age, 11.7years) underwent a total of 45 embolization sessions. The median Spetzler-Martin grade was 3 (range 1 to 4). The primary endpoint was achieved in 19 patients (82.6%). Complete angiographic occlusion of the AVM was obtained in 21 patients (91.3%) immediately after embolization and at the 6-month follow-up. Embolization-related complications were observed in three patients (13%). None of the complications resulted in permanent functional disability or death. In two patients (8.7%), the AVM could not be completely occluded by embolization alone and the patients were referred to radiosurgery and microsurgery, respectively. Onyx embolization of AVM in pediatric patients with the intention to cure resulted in high occlusion rates without increasing neurological disability or death. The development of new embolization techniques and devices seems to improve the safety of Onyx embolization.

Results for a series of 697 arteriovenous malformations treated by gamma knife: influence of angiographic features on the obliteration rate.

Stereotactic radiosurgery (RS) is an effective tool in treating brain arteriovenous malformations (AVMs). Careful study of AVM angiographic characteristics may improve results. To report the long-term outcomes of Gamma Knife RS (GKRS) in brain AVMs, focusing on how the angioarchitectural and hemodynamic parameters of AVMs affect the post-RS results. This was a retrospective, longitudinal study of 697 consecutive GKRS treatments of brain AVMs in 662 patients performed at a single center between 1993 and 2005. The mean age of the patients was 37 years; the median AVM volume was 3.6 cm(3); and the mean follow-up was 11 years. Forty-five percent of patients presented with intracranial hemorrhage; 44% underwent embolization; and 7% had multiple RSs. AVM characteristics in the RS-planning angiograms were analyzed, and their relationship to the post-RS obliteration rate was determined by univariate and multivariate analyses. The obliteration rate after a single RS was 69.3%; after multiple RS, it was 75%. Positive predictors of obliteration included compact nidus (odds ratio = 3.16; 95% confidence interval, 1.92-5.22), undilated feeders (odds ratio = 0.36; 95% confidence interval, 0.23-0.57), smaller AVM volume (odds ratio = 0.95; 95% confidence interval, 0.92-0.99), and higher marginal dose (odds ratio = 1.16; 95% confidence interval, 1.06-1.27). Improvement or clinical stability was observed in 89.3% of patients; postprocedural bleeding was noted in 6.1%; and clinical worsening attributable to RS was seen in 3.8%. The annual risk of hemorrhage in the 4 years after RS was 1.2%. GKRS yielded a good long-term clinical outcome in most patients. Certain angiographic features of brain AVMs such as a well-defined nidus and undilated feeder arteries contribute to AVM occlusion by RS. GKRS can be regarded as the treatment of choice for AVMs <6 cm(3), even after bleeding.

Brain AVM/Fs: What is the Role of the Combined Treatment Strategies?

Cerebral Arteriovenous Malformations (AVM) are complex vascular formations, variable in size and angioarchitecture and they may locate at any part of the brain. They may present with epilepsy or focal neurological signs and occasionally they are discovered incidentally. They may also rupture, creating intracranial hemorrhage associated with considerable morbidity and mortality. As a consequence these lesions should be, most of the time, be treated. There are three treatment options: surgery, embolization and radiosurgery. What treatment modality is best for each particular case depends on the size, location, age and clinical presentation (i.e., hematoma) of the lesion. Two and sometimes three treatment modalities can be used in combination for a successful treatment. Since 1999 until 2013, 423 patients have been treated in our department. A total of 608 interventions were performed (average: 1.5 procedures per patient). The most common treatment was embolization either alone or in combination with surgery and more often radiosurgery. The total occlusion rate that was accomplished by embolization alone was 36%. Most AVM remnants after embolization were treated with γ-knife radiosurgery. The overall occlusion rate of the combined embolization/γ-knife treatment is 87% (90% for lesion diameter shorter than 3 cm, 82% for diameter longer than 3 cm). In this series pre-radiosurgical embolization was performed with histoacryl and it was targeted to volume reduction. This was the reason the therapeutic result of radiosurgery was facilitated by pre-radiosurgical embolization. Surgical treatment either alone or in combination with pre-operative embolization results in total occlusion of brain AVMs, with low morbidity (no mortality in this surgical series). It is important to emphasize that meticulous selection of the surgical cases was performed (up to Spetzler and Martin grade III). Morbidity/mortality associated to AVM treatment were post-embolization bleeding or ischemia, radiation edema and/or necrosis. One post surgical bleeding was encountered in this series. In conclusion, combined treatment of brain AVMs results in very successful therapeutic management of these lesions. If meticulous selection of treatment strategies is performed for every single patient, complication rates will keep at a satisfactory low rate.

Endovascular treatment of unruptured and ruptured brain arteriovenous malformations with Onyx18: a monocentric series of 84 patients

BackgroundBrain arteriovenous malformations (AVMs) are a rare pathology, and their treatment is discussed. The development of techniques and materials in endovascular, radiosurgical, and neurosurgical fields led to higher rates of...

Endovascular treatment of brain arteriovenous malformations using a liquid embolic agent: results of a prospective, multicentre study (BRAVO)

To evaluate the safety and efficacy of a new liquid embolic agent in brain arteriovenous malformation (bAVMs) embolisation. A prospective, multicentre series was conducted at 11 interventional centres in Europe to evaluate embolisation of bAVMs with the new liquid embolic agent. Technical conditions, complications, clinical outcome and anatomical results were independently analysed. From December 2005 to December 2008, 117 patients (72 male; 45 female, aged 18-75 years) were included. Clinical presentation was mostly haemorrhage (34.2 %) and seizures (28.2 %). Most AVMs were located in the brain hemispheres (85.5 %). AVMs were <3 cm in 52.1 % of patients and ≥ 3 cm in 47.9 %. Morbidity was observed in 6/117 patients (5.1 %), related to haemorrhagic events in 2 cases and non-haemorrhagic complications in 4 cases. Five patients (4.3 %) died in relation to the treatment (bleeding in 4 patients and extensive venous thrombosis in 1). Complete occlusion of the AVM by embolisation alone was obtained in 23.5 % of patients. Complementary treatment was performed in 82.3 % of patients with partial AVM occlusion, mostly radiosurgery. In this prospective, multicentre, European, observational series, the new liquid embolic agent proved to be suitable for BAVM embolisation, with acceptable morbidity and mortality and good efficacy. • Numerous interventional techniques have been used to embolise brain arteriovenous malformations (AVMs). • This prospective multicentre study demonstrates the suitability of a liquid embolic agent. • The safety of treatment using Onyx is acceptable. • Such embolisation leads to complete AVM occlusion in 23.5 % of patients.