Treatment Of Arteriovenous Malformations Research Articles

Complications and functional outcomes of microsurgical removal of arteriovenous malformations with preoperative endovascular embolization

Background. Brain arteriovenous malformations (AVMs) are the most complex pathology in vascular neurosurgery. Collecting and summarizing data on the results of brain AVM treatment is extremely important.Objective. Analysis of complications and functional outcomes of the AVM microsurgery with preoperative endovascular embolization. Material and methods. The study included 56 patients with brain AVMs who underwent preoperative embolization at the N.N. Burdenko National Medical Research Center of Neurosurgery. The control group included 113 patients who underwent only microsurgical removal of AVM. Within the framework of this article, the features of preoperative embolization, such as radicality, timing and number of procedures, the choice of adhesive compositions, and the causes of functional deterioration and complications of the combined treatment are described. A comparative analysis of functional outcomes is performed by means of the pseudo-randomization method. Results. The radicality of AVM preoperative embolization was >75% in 21 patients (37.5%), 75-50% in 10 patients (17.9%), and <50% in 25 patients (44.6%), respectively. The average interval between embolization and surgery was 1.84 days (0-19 days). The mean 1.74 afferents (1-5 afferents) were embolized during one endovascular intervention. The radicality of the combined treatment of brain AVM was 98.2%; the lethality rate was 3.6% (2 cases). The functional outcomes of surgery in pseudo-randomization analysis did not differ statistically. In the discussion, the obtained results are compared with the published data. Conclusion. Preoperative endovascular embolization brings acceptable functional outcomes for complex brain AVMs; however, it has a risk of complications. Successful AVM treatment requires careful selection of patients and a multidisciplinary approach.

Neurophysiological monitoring during endovascular treatment of brain arteriovenous malformations: A meta-analysis.

Treatment of brain arteriovenous malformations (b-AVM) carries a risk of iatrogenic injury to eloquent brain regions. Intraoperative neuro-monitoring (IONM) has increasingly been used to monitor spontaneous or evoked neural activity during neurosurgery, but its use is not as well characterized in the endovascular treatment (EVT) of b-AVMs. We aimed to provide a systematic review and meta-analysis of studies reporting any neurological deficit after b-AVM embolization with IONM, with or without provocative test (PT), and no-IONM. This systematic review followed the PRISMA guidelines. Medline, EMBASE, and Scopus were searched from conception until March 1, 2022 for studies evaluating EVT with IONM and PT. Primary outcome was the rate of postoperative neurological deficits in EVT with IONM versus no-IONM, while secondary outcome was the subanalysis of IONM with or without PT. Meta-analysis was performed using the Mantel-Haenszel method and random effects modeling. Six studies reached synthesis. Out of a total of 192 EVT, 14 events occurred. Results demonstrated a nonsignificant trend favoring IONM compared to no-IONM to prevent neurological deficits (OR 0.09, 95% CI 0-4.68). Among the EVT with IONM, PT was done in 411 branches with 10 events (0.2%) despite a negative PT. There was a nonsignificant trend favoring IONM plus PT compared to IONM without PT (OR 0.16, 95% CI 0.02-1.07). Our study suggests that b-AVM EVT with IONM plus PT might reduce rates of postprocedural neurological deficits compared with EVT without IONM. Further studies are needed to confirm these results.

Efficacy and safety of embolo-sclerotherapy of arteriovenous malformations with foam sodium tetradecyl sulphate.

To evaluate the efficacy and safety of embolo-sclerotherapy (EST) particularly with foamed sclerotherapy in the treatment of arteriovenous malformations (AVMs). All patients with AVM who underwent interventional therapy i.e. EST from January 1st, 2015 - December 31st, 2019 were identified through a prospective database. Types of AVM were classified according to Schobinger's classification. The outcome measures assessed efficacy and complications. The former was divided into four groups: no response, mild response, moderate response, and complete response.. Complications were defined as any tissue or functional damage, distal embolization or tissue reaction. Continuous variables were compared using analysis of variance (ANOVA) F test and discrete variables were analysed using χ2 tests. P<0.05 was considered significant. A total of 65 patients were included. There was no statistical difference amongst the volume of foam STS 3% or alcohol used across all types of AVM. Overall, majority of patients (86.2%) reported some degree of improvement following interventional therapy. Six (9.2%) patients experienced complications including necrosis and amputation. The proportions of complication were significantly different across the categories (P=0.009). Patients with type III AVM seemed to report more complications than others. Foam sclerotherapy was clinically effective and safe for patients with AVM. This study showed that foam sclerotherapy with STS 3% provided a safe and efficacious alternative sclerosant to ethanol despite it was not often reported to be used to treat AVM. However, a combination of embolic agents is likely required to treat type IV AVMs.

Treatment of arteriovenous malformations associated with ruptured intracranial aneurysm

Treatment of arteriovenous malformations associated with ruptured intracranial aneurysm

Recurrence of arteriovenous malformations of the brain after complete surgical resection. Kuopio University Hospital experience and systematic review of the literature

Treatment for arteriovenous malformations of the brain (bAVMs) aims to achieve complete removal or occlusion of the lesion in order to eradicate the risk of rupture and subsequent morbidity associated with these lesions. Despite initially successful treatment, bAVMs may carry a risk of recurrence especially in younger patients. We studied the rate of recurrence of surgically treated bAVMs at Kuopio University Hospital (KUH) in 1981–2021. The study population was collected retrospectively from KUH databases and presented a cohort of 135 surgically treated bAVMs with complete occlusion of the lesion. We also performed a systematic literature review on this topic. In our series, 6 out of 135 (4.4%) patients with angiographically confirmed removal of the lesion later developed a recurrent bAVM with a median time to diagnosis of recurrence of 7.46 years. In pediatric patients, the rate was 5 out of 17 (29.4%). bAVM recurrence was associated with age (p = 0.001) and initial hemorrhagic presentation (p = 0.039). Median age of the study population was 37 years (min 0, max 70), and 51/135 (37.8%) of the patients were female. Seventeen (12.6%) of the 135 bAVM patients were considered pediatric (18 years old or younger) at the time of the operation. In the literature review, 79 of 1739 (4.5%) of surgically treated patients later developed a recurrence with a mean delay of 3.1 years until diagnosis of recurrence. Young surgically treated bAVM patients with a hemorrhagic presentation at initial diagnosis are at a relatively high risk of bAVM recurrence. Follow-up imaging should be arranged for these patients in order to prevent rupture from a recurrent bAVM and subsequent morbidity.

How I do it: surgery for spinal arteriovenous malformations.

Spinal arteriovenous malformations (AVM) are rare lesions. They may present with intramedullary hemorrhage or edema, often inducing severe neurological deficits. Active treatment of spinal AVMs is challenging even for experienced neurosurgeons. Anticipation of anatomy and AVM angiocharacteristics from preoperative imaging is key for successful treatment. Information gathered from MRI and DSA has to be then matched to intraoperative findings. This is a prerequisite for reasonably safe and structured lesion removal. We provide a structured approach for surgical treatment of spinal AVMs, supplemented by high-resolution video and imaging material.

A Single-Center Retrospective Analysis of 14 Head and Neck AVMs Cases Treated with a Single-Day Combined Endovascular and Surgical Approach.

Arteriovenous malformations (AVMs) are rare congenital defects of vascular development whose treatment remains challenging. The paper presents a retrospective single-center study of 14 patients with AVMs of the head and neck region undergoing combined endovascular and surgical treatment in a single day. AVM architecture and therapeutic strategies were determined on the basis of angiographic studies, while the psychological involvement of each patient was assessed by means of a questionnaire. Most of the 14 patients achieved satisfactory clinical results with no recurrences, good aesthetic and functional results, and most patients reported improved quality of life. The combined endovascular and surgical approach is an effective treatment for AVMs of the head and neck and performing it on the same day is a possible option often accepted by patients which guarantees operative advantages for the surgeon.

Endovascular Treatment of Peripheral Arteriovenous Malformations (AVMs): Do Angiographic Outcomes Relate to the Quality of Life?

Purpose: Patients with arteriovenous malformations (AVMs) have a lower health-related quality of life (QoL) than the general population. QoL assessment of patients with peripheral AVMs after endovascular treatment is scarce in the literature. Radiologic and clinical outcomes are not always correlated in vascular malformation treatment. This study aimed to investigate the relationship between clinical outcomes, QoL, and angiographic outcomes. Materials and Methods: Patients with peripheral AVM that underwent endovascular treatment between January 2009 and December 2021 in a single center were retrospectively evaluated. Patients’ characteristics (age, sex), AVM characteristics (Schobinger classification, location, angiographic architecture), previous treatment, treatment characteristics (type of endovascular approach, embolizing agent and number of sessions), percentages of angiographic response, complications, and recurrence were evaluated. The angiographic architecture was evaluated according to the Yakes classification. The questionnaire was applied for evaluation of clinical response and QoL. Patients older than 12 years and those who can be contacted were included in clinical and QoL analysis. Clinical response was defined as improvement in the patient’s most important pretreatment symptom. Treatment response was defined as clinical response plus >50% angiographic response. Results: Eighty-six patients (41 males [47.7%], 45 females [52.3%]) were included in angiographic analysis. The mean age was 28.44±12.99 years (range=5–61). Forty-three patients (50%) had previous treatment. The median number of sessions was 2 (range 1–15, InterQuartile Range [IOR]=2). Sixty-one patients (30 males [49.2%], 31 females [50.8%]) were included in clinical analysis. The clinical response rate was 73.8%, 95% confidence interval (CI) [0.60, 0.84]. The treatment response rate was 45.9%, 95% CI [0.33, 0.59]. The complication rate was 8.2%. Before treatment, 48 patients (78.7%) reported a negative impact on their QoL. Thirty-three of 48 patients (68.8%) reported improvement on their QoL after treatment. Higher Schobinger stages were related to a negative impact on QoL before treatment (p<0.01). Yakes types were not related to QoL (p=0.065). Clinical response was related to improvement on QoL after treatment (p<0.01). Angiographic and treatment responses were not related to improved QoL after treatment (p=0.52 and p=0.055, respectively). Conclusion: Angiographic architecture and outcomes were not always reflected in QoL after endovascular treatment. Clinical Impact This study’s findings will help clinicians with what to focus on in AVM treatment and how to monitor patients with peripheral AVM after endovascular treatment. Rather than relying too much on the angiographic response, patients should be checked for symptoms and quality of life improvement. No clear data in the literature regarding the applicability of the Yakes Classification in patients with previous treatment. This study questioned the applicability of the Yakes Classification in patients with previous treatments. In this study, type 4 AVMs were more common in patients with previous treatment.

Embolization as stand-alone strategy for pediatric low-grade brain arteriovenous malformations

ObjectivesWe evaluated the safety and efficacy of endovascular embolization as first-line stand-alone strategy for the treatment of low-grade brain arteriovenous malformations (bAVMs) (Spetzler Martin [SM] grade I and II) in pediatric patients. In addition, we assessed the predictors of procedure-related complications and radiographic complete obliteration in a single session. Material and methodsWe conducted a single center retrospective cohort study of all pediatric (≤18 years) patients who underwent embolization as a stand-alone strategy for low-grade bAVMs between 2010 and 2022. Safety was measured by procedure-related complications and mortality. Efficacy was defined as complete angiographic obliteration after the last embolization session. ResultsSixty-eight patients (41 females; median age 14 years) underwent a total of 102 embolization sessions. There were 24 (35%) SM grade I lesions and 44 (65%) grade II. Six procedure-related complications (5.8% of procedures) were observed and no deaths were reported. All the complications were intraoperative nidus ruptures. A single draining vein was the only significant predictor of procedure-related complications (OR=0.10; 95% CI 0.01 – 0.72; p=0.048). Complete angiographic obliteration was achieved in 44 patients (65%). In 35 patients (51%) the bAVM was completely occluded in one session. The bAVM nidal size was a predictor of complete obliteration in one session (OR=0.44; 95% CI, 0.21–0.80; p=0.017). ConclusionEndovascular treatment as a stand-alone strategy for pediatric low-grade bAVMs is an adequate first-line approach in high volume centers with endovascular expertise. Nidal size evaluation is relevant in order to optimize patient selection for embolization as a stand-alone treatment modality.

477 Stereotactic Radiosurgery With Versus Without Prior Onyx Embolization for Brain Arteriovenous Malformations

INTRODUCTION: Investigations of the combined effects of neoadjuvant Onyx embolization and stereotactic radiosurgery (SRS) on brain arteriovenous malformations (AVM) have not accounted for initial angioarchitectural features prior to neuroendovascular intervention. METHODS: The International Radiosurgery Research Foundation AVM databases from 1987–2018 were retrospectively reviewed. Patients were categorized, based on AVM treatment approach, into Onyx embolization and SRS (OE+ SRS) or SRS alone (SRS-only) cohorts and then propensity score-matched in a 1:1 ratio. Primary outcome was AVM obliteration. Secondary outcomes were post-SRS hemorrhage, all-cause mortality, radiologic and symptomatic radiation-induced changes (RIC), and cyst formation. Comparisons were analyzed using crude rates and cumulative probabilities adjusted for competing risk of death. RESULTS: The matched OE + SRS and SRS-only cohorts each comprised 53 patients. Crude rates (37.7% vs. 47.2% for OE + SRS vs. SRS-only cohorts, respectively; OR = 0.679, p = 0.327) and cumulative probabilities at 3, 4, 5, and 6 years (33.7%, 44.1%, 57.5%, and 65.7% for OE + SRS cohort vs. 34.8%, 45.5%, 59.0%, and 67.1% for SRS-only cohort, respectively; SHR = 0.961, p = 0.896) of obliteration were similar between the matched cohorts. The secondary outcomes of the matched cohorts were also similar. Asymptomatic and symptomatic embolization-related complication rates in the matched OE + SRS cohort were 18.9% and 9.4%, respectively. CONCLUSIONS: Pre-SRS AVM embolization with Onyx does not appear to negatively influence outcomes after SRS. Our analyses, based on de novo nidal characteristics, thereby refute previous studies that found detrimental effects of Onyx embolization on SRS-induced AVM obliteration. However, given the risks incurred by nidal embolization using Onyx, this neoadjuvant intervention should be employed judiciously in multimodal treatment strategies involving SRS for appropriately selected large-volume or angioarchitecturally high-risk AVMs.

A rare case of bilateral arteriovenous malformation of the lungs

Arteriovenous malformation of the lungs is a disease characterized by a pathological «direct» connection of the vessels of the pulmonary artery system with the pulmonary veins and the formation of a right-left intrapulmonary shunt. The incidence of arteriovenous malformation of the lungs (AVML) is 2—3 cases per 100,000 population, 10 % cases are diagnosed in children. The degree of manifestation of symptoms in arteriovenous malformation of the lungs directly depends on the vessels diameter at the level of which blood shunting occurs. The disease is characterized by a typical triad of clinical manifestations: cyanosis (SaO2 &lt; 85 %), polycythemia (Hb &gt; 185 g/l, Ht &gt; 52 %, RBC &gt; 5.1 · 1012/l), changes in the end phalanges of the fingers in the form of «drumsticks». The most severe complications of arteriovenous malformation of the lungs are hemoptysis (pulmonary bleeding), hemothorax, abscess and cerebral infarction. The basis for the diagnosis of the disease are radiological methods, in particular, helical computed angiography of the pulmonary vessels. Treatment of arteriovenous malformation of the lungs can be carried out by embolization of the arterial vessels of the site of the malformation by resection interventions on the lungs or a combination of the two methods described above. Over the past 32 years, in the clinic of thoracic surgery and invasive diagnostic methods of the SI «National Institute of Phthisiology and Pulmonology named after F.G. Yanovsky NAMS of Ukraine» 20 were treated with a diagnosis of arteriovenous malformation of the lungs. In the literature, there are very few reports on the treatment of bilateral arteriovenous malformation of the lungs, so we would like to give a clinical example of just such a case.The article presents a clinical example of bilateral arteriovenous malformation of the lungs.

Arteriovenous Malformations:Endovascular Techniques and Devices

Endovascular embolization using liquid materials is a safe and effective treatment option for cerebral arteriovenous malformations(AVM). Onyx and n-butyl cyanoacrylate, currently available in Japan, have specific features. Appropriate embolic agents should be selected based on their characteristics. Transarterial embolization(TAE)is the standard endovascular treatment approach. However, there have been some recent reports regarding the efficacy of transvenous embolization(TVE). TVE is potentially curative for small AVM with hemorrhagic onset, inaccessible arterial feeders, deep location, and/or a single draining vein. In specific cases, TVE may provide a higher chance of complete obliteration of the AVM than TAE. Some unsolved problems need further clarification, such as the relative positions of liquid embolization against direct surgery, dealing with unruptured AVM, and effective treatment for high-grade AVM.

Gamma Knife Radiosurgery in Partially Embolised Arteriovenous Malformations: Management Dilemmas and Outcomes.

The role of Gamma Knife radiosurgery (GKRS) in partially embolized arteriovenous malformations (AVMs) has always remained a subject of debate. The aim of this study was to evaluate the efficacy of GKRS in partially embolized AVMs and to analyze factor that influence its obliteration. This was a retrospective study from a single institute performed over a period of 12 years (2005-2017). It included all patients who underwent GKRS for partially embolized AVMs. Demographic characteristics, treatment profiles, and clinical and radiological data were obtained during treatment and follow-up. Obliteration rates and factors affecting the same were sought and analyzed. A total of 46 patients with a mean age of 30 years (range: 9-60 years) were included in the study. Follow-up imaging was available for 35 patients either by digital subtraction angiography (DSA) or magnetic resonance imaging (MRI). We found complete AVM obliteration in 21 patients (60%): one had near total obliteration (>90% obliteration), 12 had subtotal obliteration (<90%), and one had no change in the volume following GKRS. Following embolization alone, an average of 67% of the AVM volume was obliterated which resulted in an average 79% final obliteration rate after Gamma Knife radiosurgery. Mean duration to complete obliteration was found to be 3.45 years (range: 1-10 years). There was a significant difference (P = 0.04) in the mean interval between embolization and GKRS among cases with complete obliteration (12 months) and those with incomplete obliteration (36 months). There was no significant difference (P = 0.49) in the average obliteration rate between the ARUBA-eligible unruptured AVMs (79.22%) and ruptured AVMs (79.04%). Bleeding after GKRS during the latency period had a negative impact on obliteration (P = 0.05). Other factors like age, sex, Spetzler-Martin (SM)-grade, Pollock Flickinger score (PF-score), nidus volume, radiation dose, or presentation before embolization had no significant influence on obliteration. Three patients had permanent neurological deficits after embolization and none after radiosurgery. Six out of nine patients (66%) presenting with seizures were seizure-free after the treatment. Hemorrhage was noted in three patients following combined treatment and were managed non-surgically. Obliteration rates in partially embolized AVM after Gamma Knife are inferior when compared to Gamma Knife alone; moreover with volume staging and/or dose staging being increasingly plausible due to the new ICON machine, embolization may be completely replaced. However we have shown that in complicated and carefully chosen AVMs, embolization followed by GKRS is a valid modality of management. This study represents a real-world picture of individualized AVM treatment depending on patient choices and resources available.

Arteriovenous Malformations: An Update on Models and Therapeutic Targets

Arteriovenous malformations (AVMs) are an anomaly of the vascular system where feeding arteries are directly connected to the venous drainage network. While AVMs can arise anywhere in the body and have been described in most tissues, brain AVMs are of significant concern because of the risk of hemorrhage which carries significant morbidity and mortality. The prevalence of AVM’s and the mechanisms underlying their formation are not well understood. For this reason, patients who undergo treatment for symptomatic AVM’s remain at increased risk of subsequent bleeds and adverse outcomes. The cerebrovascular network is delicate and novel animal models continue to provide insight into its dynamics in the context of AVM’s. As the molecular players in the formation of familial and sporadic AVM’s are better understood, novel therapeutic approaches have been developed to mitigate their associated risks. Here we discuss the current literature surrounding AVM’s including the development of models and therapeutic targets which are currently being investigated.

Letter: Risk for Hemorrhage the First 2 Years After Gamma Knife Surgery for Arteriovenous Malformations: An Update.

To the Editor: We have read with great interest the article by Karlsson et al1 titled “Risk for Hemorrhage the First 2 Years After Gamma Knife Surgery for Arteriovenous Malformations: An Update.” The premise of this study was based on the findings of a 2001 study that demonstrated the risk of hemorrhage after gamma knife surgery (GKS) for arteriovenous malformations (AVMs) to be strongly correlated with large AVM size, older age, and lower therapeutic dose.2 However, contradictory data collected 17 years later revealed the risk of hemorrhage was not related to AVM size or patient age.3 To clearly define predictors of hemorrhage, the authors retrospectively reviewed the outcome of 5037 patients treated with GKS for AVM.1 The average rate of hemorrhage was determined to be 2.4%, where larger AVM size, older age, and lower therapeutic dose served as significant (P < .01) risk factors, consistent with findings from the original study.1,2 AVM location (P = .16), embolization (P = .27), and history of pre-GKS hemorrhage (P = .20) were found to be nonsignificant predictors for post-GKS hemorrhage.1 The identification of clear hemorrhage risk factors after GKS for AVM in this large, heterogeneous cohort provides clinicians with more concrete guidelines for AVM management.1 The clinical management of cerebral AVMs remains challenging due to AVM heterogeneity in size, biological composition, anatomic location, and associated symptoms.4 Thus, the treatment of AVMs to reduce hemorrhage risk must be conducted in an individualized manner specific to patient presentation and AVM profile. Although no formal guidelines exist regarding treatment of unruptured AVMs, a landmark randomized trial of unruptured brain arteriovenous malformations (trial) revealed the superiority of medical management compared with interventional therapy.5 Interventional therapy was associated with an increased risk of stroke or death as compared with medical management alone (P < .0001; hazard ratio 3.70; 95% CI 1.85–7.14).5 Five-year follow-up data confirmed these findings.6 With this understanding, along with identifying general risk factors and prevalence rates of AVM hemorrhage after GKS, it would be valuable to investigate the impact of hemorrhage on mortality and morbidity in this cohort of patients undergoing interventional therapy. Doing so, while controlling for confounding variables, such as the Spetzler-Martin grade, AVM nidus morphology or location, would be clinically significant and aid in deciding which patients would truly benefit from GKS. Hemorrhage is the leading cause of morbidity and mortality associated with AVMs.7 Consequently, common symptoms of AVM-related hemorrhage such as seizures and headaches severely impair quality of life (QOL).8,9 While it can be hypothesized that post-GKS AVM hemorrhage would have profound implications for QOL outcomes, there are no reports in the literature detailing this relationship. Future studies should investigate the impact of post-GKS hemorrhage on QOL metrics, especially as GKS continues to improve and be used for more complex disease. This study by Karlsson et al1 provides a strong foundation for the future investigation of invaluable QOL metrics to guide medical decision-making in a manner that targets patient-specific QOL discrepancies while bridging this apparent gap in the literature.

Pressure cooker technique in cerebral AVMs and DAVFs: different treatment strategies.

The pressure cooker technique (PCT) was developed to enable safer and more extensive embolization of hypervascular lesions by simultaneously minimizing backflow of liquid embolic materials and thus reduce the risk of non-target embolization of adjacent healthy vessels. We report our experience in applying the PCT to cerebral arteriovenous malformations (AVMs) and dural arteriovenous fistulas (DAVFs) and additionally suggest our technical adjustments. We retrospectively reviewed all patients suffering from AVMs or DAVFs that were treated with the PCT between 2018 and 2020 in two university hospitals. The endpoints of the study were clinical safety and the technical efficacy. The endpoints of the study were clinical safety and the technical efficacy. Clinical safety was the absence of death, major or minor symptomatic stroke, TIA and procedure-related intracranial bleeding (SAH) in the peri-procedural period until dismission. Good clinical outcome was defined as no deterioration of the modified Rankin Scale (mRS) score (comparing the pre- and post-procedural mRS evaluated by a trained neurologist at admission and dismission). The technical efficacy was considered as the complete embolization occlusion of the target vessels of the lesion documented on the final control angiogram. Long-term follow-up evaluation was not intended for this study as it was not available for all patients. Fifteen consecutive patients (6 women; mean age 55 y; range 20-82 y) with seven AVMs and eight DAVFs met the inclusion criteria. The primary clinical safety end point was obtained in all cases as no intraprocedural complications were encountered. All patients had a good clinical outcome with no difference between the pre- and post-mRS scores. The primary efficacy end point was reached in all cases. The PCT is a safe and effective technique in the treatment of cerebral AVMs and DAVFs. Adding an easy and fast step to the procedure, namely the injection of contrast media to test the complete obstruction by the plug, the risk of reflux seems to additionally be reduced.

A complex approach to the treatment of arteriovenous IV-V degree malformations according to Spetzler‒Martin scale. Clinical case

Four therapeutic approaches have been developed for the treatment of arteriovenous malformations (AVMs): microsurgery, radiosurgery, embolization, and conservative treatment. The lack of consensus regarding the choice of treatment method and the different specializations of the doctor who are onvolved to the patient with AVM often determine the wrong treatment strategy. We performed a prospective analysis of the results of AVM of the IV degree according to Spetzler‒Martin scale, 4–5 points on the Buffalo scale complex treatment, based on clinical and tomographic data after the use of partial endovascular embolization and radical microsurgical removal of the AVM node assisted by cell saving technology. According to cerebral angiography 4 months follow-up there is no visible AVM vessels, the malformation was completely resected.Treatment of large and giant AVMs (IV and V degrees according to the Spetzler‒Martin scale) requires tailored surgical treatment approache using endovascular, microsurgical and radiosurgical techniques, but in many cases without achieving a radical result. The use of cell saver technology is necessary to reduce the risks of intraoperative complications associated with blood loss during microsurgical intervention, and enables radical removal of the AVM and recovery of the patient. The role of cell saver technology is crucial in vascular microsurgical interventions, which are often accompanied by a significant volume of blood loss, ensuring rapid autologous hemotransfusion and restoration of circulating blood volume. Endovascular embolization is a necessary step to reduce the risks of intraoperative complications during microsurgical intervention, which, together with the use of cell saver technology, makes it possible to achieve radical AVM removal and patient recovery.

Clinical and anatomic description of patients with arteriovenous malformation treated with endovascular therapy in a Mexican population.

Arteriovenous malformations (AVMs) are benign congenital lesions. The estimated prevalence is 10-18 per 100,000 individuals, with an incidence rate of 1.1-1.4 per 100,000 person-year; only 12% of AVMs present symptoms during life. It is important to study different characteristics associated with AVMs because these patients require multidisciplinary treatment. A descriptive, observational, longitudinal, and retrospective study was carried out from January 15, 2016 to October 19, 2021. Convenience sampling was used on patients diagnosed with arteriovenous malformation. Sociodemographic data was obtained, such as: sex, age, site, predominant symptoms, clinical debut, type of malformation, data associated with post therapy evolution, type of embolizing agent used, associated complications, Rankin scale, and death. Data from 535 procedures was collected, we calculated an incidence of 4.4 cases per million inhabitants. Ninety procedures in 56 patients that used endovascular therapy were obtained with a female-male ratio of 0.75 and an age distribution of 35±14 (SD). A 36.3±11.5 (SD) mm diameter was registered. There was a 33% success rate for endovascular surgery. The multidisciplinary treatment of AVMs is made up of three pillar techniques: microsurgical resection, embolization, and radio-neurosurgery. It is extremely important to make an appropriate decision, with an emphasis on achieving better functional outcomes for the patient. Although neurological endovascular therapy was initially used as an adjuvant treatment for neurosurgery and radio-neurosurgery, it has been used more and more frequently as the first line of treatment.

Abstract 53: Long-term Treatment Risk Of Hemorrhage In Unruptured Brain Arteriovenous Malformation Patients

Introduction: The long-term effects of interventional treatment (with surgery, stereotactic radiosurgery, or endovascular embolization) for unruptured brain arteriovenous malformations (uBAVM) are uncertain. We address this in a large multi-center international cohort study comparing risk of intracranial hemorrhage (ICH) in the treated and untreated course of uBAVM patients. Methods: We pooled individual patient data (n=3,291) from 10 cohorts and imputed missing data. Survival analysis was performed from time of uBAVM diagnosis to intracranial hemorrhage (ICH) using Cox models, stratified by cohort, censoring at death or last follow-up, and including BAVM interventional treatment as a time-varying covariate. We tested for an interaction of treatment with follow-up time, then estimated the association of interventional treatment with ICH, adjusting for propensity quintile. Individual treatment propensity scores were calculated using logistic regression with Spetzler-Martin grade, sex, diagnosis age and year, cohort, and presence of presenting symptoms (seizures, headaches, and/or deficits). Results: Median cohort age was 36 years, 48% were female, and 77% received ≥1 treatment modality for uBAVM during follow-up. 373 ICH occurred during 32,054 person-years of follow-up (median=6.6y), for an ICH rate of 1.16 per 100 P-Y. Overall, treatment was not associated with risk of ICH (HR=1.12, 95% CI=0.89-1.51, p=0.33). However, we observed a strong interaction between treatment and follow-up time (p&lt;0.001): between 0-1 year, treatment was associated with higher risk of ICH (HR=3.48, 95% CI: 2.26-5.37, p&lt;0.001); between 1-10 years, we found no association between treatment and risk of ICH (HR=1.02, 95% CI: 0.73-1.45, p=0.87); after 10 years, treatment was associated with a lower risk of ICH (HR=0.46, 95% CI: 0.30-0.70, p&lt;0.001). Survival curves for untreated and treated courses crossed around 17 years. Conclusion: After accounting for treatment propensity for uBAVM, we found an initial increased risk of ICH in the treated relative to untreated course, which continually declined over time with survival curves crossing around 17 years. These results require confirmation in a randomized controlled trial of uBAVM with long-term follow-up.

Brain arteriovenous malformations of the middle cerebral artery region: image characteristics and endovascular treatment based on a new classification system

BackgroundTo date, few studies have investigated the use of endovascular treatment (EVT) for brain arteriovenous malformations (BAVMs) in the supplying area of the middle cerebral artery (MCA). Moreover, no suitable classification was aimed at EVT for MCA-BAVMs. Therefore, this study proposed a new classification.MethodsThis study retrospectively collected 135 MCA‑BAVMs. They were classified into four types: Type I BAVMs located above the M1 segment; Type II BAVMs located in the region around the Sylvian fissure; and Type III BAVMs located in the supplying region of the M4 segment and subdivided into types IIIa and IIIb. The relevance of various types of MCA-BAVMs and their imaging characteristics and EVT outcomes was analyzed by ordinary one-way ANOVA, Tukey's multiple comparisons test and the chi-square test.ResultsThe 135 patients averaged 33.8 ± 14.7 years and included 75 females (55.6%, 75/135). Among them, 15 (11.1%, 15/135), 16 (11.9%, 16/135), 54 (40%, 54/135), and 50 (37%, 50/135) MCA-BAVMs were type I, II, IIIa and IIIb, respectively. After EVT, a good outcome was achieved in 97% of patients. Statistical analysis showed that type I BAVMs were smaller than type II and IIIb BAVMs (P value < 0.05), and type IIIb BAVMs were larger than type I and IIIa BAVMs (P value < 0.05). Deep vein involvement in type I and IIIb BAVMs was more common than in other types (P value < 0.05), and intraventricular hemorrhage (IVH) was also more common (P value < 0.05). The normal morphology in type IIIb was less than that in the other types (P value < 0.05). Type IIIa BAVMs had a higher degree than other types (P value < 0.05).ConclusionThe present study demonstrated that the new classification of MCA-BAVMs can be used to evaluate imaging characteristics and EVT outcomes in different types. In addition, EVT may be a safe treatment modality for MCA‑BAVMs.