Delayed versus immediate intervention of ruptured brain arteriovenous malformations:A case report

BACKGROUND Brain arteriovenous malformations(bAVMs)remains one of the most prevalent causes of intracranial hemorrhage and stroke-like syndromes in the young adult population.Although it has been agreed upon that definitive treatment using either single or multi-modal approach is warranted for successful bAVM management,much debate still revolves regarding the optimal timing of definitive treatment.CASE SUMMARY In this report,we present a case of delayed,definitive endovascular treatment for ruptured bAVM in a 21-year-old female,3 mo post-ictus.The bAVM,with a left pericallosal feeding artery and cortical draining veins,was successfully obliterated through embolization using the Onyx 18.On follow-up the patient has recommenced her daily activities and experiences only mild occasional headaches with mild motor deficits.The report leads to our review on an important issue regarding the optimal timing of ruptured bAVM definitive management and bring forward the current evidence available on delayed vs immediate definitive bAVM intervention.We also highlight current issues that need to be addressed for clearer guidelines on definitive therapy initiation.CONCLUSION Current treatment paradigms of ruptured bAVM remains elusive,with substantial heterogeneity in the current literature.A consensus on the definition of“acute”vs“delayed”,management goal,follow-up length and outcome parameters are required to support formation of a clear paradigm.

Overview of peripheral arteriovenous malformations:From diagnosis to treatment methods

Based on the latest classification by the International Society for the Study of Vascular Anomalies in 2018,vascular malformations(VMs)can be categorized into simple,combined,VMs of major named vessels,and VMs associated with other anomalies.Simple VMs include lymphatic,venous,capillary,and arteriovenous malformations(AVMs).AVMs represent disorders of direct arteriovenous shunts caused by the absence of a capillary bed between the involved arteries and veins.This abnormal vascular communication causes arterial blood to accumulate in the venous vessels,thus resulting in venous hypertension and characteristic clinical manifestations,such as pulsation,tremors,and elevated temperature.AVMs can occur sporadically or as manifestations of syndromic lesions and are considered among the most complex and challenging VMs.The diagnosis and treatment of AVMs can vary depending on the lesion location and associated clinical symptoms,thus complicating their management.Herein,we discuss peripheral AVMs in terms of their clinical manifestations,imaging examinations,and staging systems to provide a comprehensive reference for the treatment,evaluation methods,and follow-up procedures for this vascular anomaly.

Embolization of brain arteriovenous malformations with squid co-polymer embolic material:Initial experience

Objective:To analyze the safety and effectiveness of the ethylene-vinyl alcohol copolymer(EVOH)liquid embolic agent Squid(Emboflu,Switzerland)for the treatment of brain arteriovenous malformations.Materials and procedures:Between April 2015 and July 2017,46 embolization treatments for brain arteriovenous malformations(BAVM)were performed in 25 patients using two Squid formulations(18 and 12).Six female and 19 male patients with a mean age of 34 years(range,9–62 years)were included.A total of 46 procedures were performed.The BAVMs were classified as Spetzler-Martin gradeⅡin 4 procedures,Ⅲin 27 procedures,and 1V in 15 procedures.Among the 25 patients,15 presented with hemorrhage,5 with seizures,and 5 with headache and neurology.The BAVMs were located in the temporal lobe in 5 patients,parietal lobe in 7 patients,frontal lobe in 3 patients,posterior fossa in 6 patients,basal ganglia in 3 patients,and parasagittal lobe in 1 patient.Results:The obliteration rate of the BAVMs ranged from 10%to 100%,with a mean of 33%.Most patients underwent their first or second embolization procedure.Four patients(8%)developed intracranial bleeding post procedure,with one death(2%).One patient(2%)experienced a seizure during the procedure;however,no intracranial bleeding was observed.Seven patients(15%)experienced perforations during catheter manipulation.One case(2%)of fractured catheter was recorded,but no significant complications were observed.The average volume of copolymer injected was 0.6 ml per nidus.Thirteen procedures used the Squid-12 formulation,29 procedures used the Squid-18 formulation,and 3 procedures used a combination of Squid-12 and-18 formulations.Conclusion:Squid is a safe and effective embolic agent for treating BAVMs.

MEK inhibitors for the treatment of extracranial arteriovenous malformations

Arteriovenous malformations(AVMs)are serious congenital vascular anomalies in which the arteries connect directly with veins without capillaries.This condition will continue to worsen without proper intervention and cause ulcers,repeated hemorrhages,and even cardiac insufficiency.Primary treatment options for AVMs include surgery and interventional treatment;however,they are associated with high risk and recurrence rates.Recent studies revealed that excessive activation of the Ras/MAPK pathway can induce the formation and development of peripheral AVM,whereas MEK inhibitors can effectively control nidus progression,making them a potential novel treatment for AVM.This review provides an up-to-date overview of correlated laboratory and clinical research to provide information for further research and clinical practice.

Absolute ethanol embolization for treatment of peripheral arteriovenous malformations

Arteriovenous malformations(AVMs)are aggressive congenital high-flow vascular anomalies,in which the feeding artery and draining vein are connected through fistulas without normal capillary networks.In severe cases,the condition may cause swelling,ulceration,bleeding,and even heart failure.Various treatment options are available for AVMs,including laser,surgical resection,embolization,and targeted drug therapy.With the development of endovascular treatment technology,absolute ethanol embolization of AVMs has become one of the first-line therapies owing to its sustained efficacy and low recurrence rate.However,administration of this therapy is challenging and may lead to serious complications if inappropriately managed.In this article,we reviewed and summarized previous clinical articles,literature reviews,and clinical trial data to comprehensively describe clinical manifestations of AVMs,the mechanism of ethanol embolotherapy,key points in treatment and management of complications,and issues that need to be addressed.We expect to provide a reliable information reference source for clinical physicians and researchers.

Imbalance of matrix metalloproteinase-9 and matrix metalloproteinase tissue inhibitor-1 may contribute to hemorrhage in cerebellar arteriovenous malformations

In this study, we determined the expression levels of matrix metalloproteinase-2 and -9 and matrix metalloproteinase tissue inhibitor-1 and -2 in brain tissues and blood plasma of patients undergoing surgery for cerebellar arteriovenous malformations or primary epilepsy （control group）. Immunohistochemistry and enzyme-linked immunosorbent assay revealed that the expression of matrix metalloproteinase-9 and matrix metalloproteinase tissue inhibitor-1 was significantly higher in patients with cerebellar arteriovenous malformations than in patients with primary epilepsy. The ratio of matrix metalloproteinase-9 to matrix metalloproteinase tissue inhibitor-1 was significantly higher in patients with hemorrhagic cerebellar arteriovenous malformations compared with those with non-hemorrhagic malformations. Matrix metalloproteinase-2 and matrix metalloproteinase tissue inhibitor-2 levels were not significantly changed. These findings indicate that an imbalance of matrix metalloproteinase-9 and matrix metalloproteinase tissue inhibitor-I, resulting in a relative overabundance of matrix metalloproteinase-9, might be the underlying mechanism of hemorrhage of cerebellar arteriovenous malformations.

Expression of angiogenic factors in cerebral arteriovenous malformations

BACKGROUND： In the process of vascularization, vascular endothelial growth factor （VEGF）, angiopoietin-2 and Tie2 are involved in the migration, differentiation and proliferation of vascular endothelial cells, and stimulate the rapid angiogenesis; Tiel and angiopoietin-1 play important roles in facilitating the formation of vascular lumen and maintaining the integrity of vascular wall. Thus the distributions and expressions may be associated with the occurrence of cerebral arteriovenous malformation. OBJECTIVE： To observe the biological effects of angiogenic factors in the occurrence and development of cerebral arteriovenous malformation. DESIGN： An observational comparative experiment. SETTINGS： Department of Neurosurgery, General Hospital of Shenyang Military Area Command of Chinese PLA; Department of Neurosurgery, General Hospital of Tianjin Medical University. PARTICIPANTS： Fresh samples of complete cerebral arteriovenous malformations resected in 47 patients were collected from the Department of Neurosurgery, General Hospital of Tianjin Medical University from August 1999 to May 2001, including 22 males and 25 females, the mean age was 34.5 years. Informed consents were obtained from all the patients or their relatives. The initial symptom was hemorrhage in 28 cases. All the patients were classified according to the clinical imaging data and Spetzler-Martin grading standard, including 11 cases of grade Ⅰ, 17 cases of grade Ⅱ, 11 cases of grade Ⅲ, and 8 cases of grade Ⅳ - Ⅴ. Normal brain tissues resected by decompression due to trauma were taken from 8 patients as controls, including 5 males and 3 females, aging 12 - 65 years. METHODS： ① The expressions of VEGF, Tie receptors, angiopoietin-1, angiopoietin-2, proto-oncogene c-myc and proliferating cell nuclear antigen（PCNA） in the samples of cerebral arteriovenous malformation were detected with immunohistochemical method. Under light microscope, the positively stained rat-anti-human factor Ⅷ-related antigens （specific marker of vascular endothelial cells） were counted, then the immuno-positive cells of the other antibodies in the visual field of neighboring section which was in ＂mirror＂ relation were counted, and the percentage of the latter to the former was considered as the labeling index of positive cells. The immunostaining intensity was classified negative （ - ）： no positive cells; positive （＋）： number of positive cells 〈 20%; moderately positive （＋＋）： number of positive cells 20% - 50%; strongly positive （＋＋＋）： number of positive cells 〉 50%. ② The differences of the enumeration data were compared with chi-squam test, and the correlation were analyzed with the linear correlation analysis. MAIN OUTCOME MEASURES： Expressions and distributions of VEGF, Tie 1 and Tie2 receptors, angiopoietin-1, angiopoietin-2, PCNA and c-myc in the samples of cerebral arteriovenons malformation and normal brain tissue. RESULTS： ① Expressions of angiogenic factors in the control group and cerebral arteriovenons malformation groups of each grade： The positive rates of VEGF, Tie2, angiopoietin-2, c-myc and PCNA expressions in the control group were significantly different from those in the cerebral arteriovenous malformation groups of each grade （ x^2=21.09 - 34.23, P 〈 0.05）, whereas the positive rates of Tiel and angiopoietin-1 expressions were close （ x^2=3.43 - 3.869, P 〉 0.05）. ② Expressions of angiogenic factors in hemorrhage group and non-hemorrhage group： The expressions of VEGF, angiopoietin-2 and PCNA in the hemorrhage group were significantly lower than those in the non-hemorrhage group （ x^2= 16.22 - 26.56, P 〈 0.05）. There ware no obvious differences in the expressions of Tiel and angiopoietin-1 expressions between the hemorrhage group and non-hemorrhage group （ x^2=3.22 - 3.78, P 〉 0.05）.The VEGF was positively correlated with the expressions of c-myc and PCNA （r = 0.728, 0.916, P 〈 0.05）. CONCLUSION： ①The expressions of angiogenic factors and related receptors may be involved in the process of cerebral arteriovenous malformation, and had important correlation the its clinical grading. ② Angiogenic factors may induce the expression of endothelial cell c-myc in cerebral arteriovenous malformation, and then interfere the cell proliferation and apoptosis.

Understanding the role of miRNAs in the pathogenesis of brain arteriovenous malformations

Brain arteriovenous malformations(AVMs)are abnormal vessels that are prone to rupture,ausing life threatening intracerebral hemorrhage(ICH).Understanding the moleaular basis of pathogenesis,timely diagnosis,and treatment of brain AVMs are some of the urgent problems in neur osur gery.MiaoRNAs(miRNAs)are small endogenous RNAs that regulate gene-epression psttranscriptionally.MiRNAs are involved in almost all biological procsss,induding cell proliferation,apoptosis,and cell differentiation.Recent studies have shown that miRNAs an be involved in brain AVMs formation and rupture.There are also extracellular forms of miRNAs.Circulating miRNAs have been detected in the blood circulation and other body fluids.Owing to their stability and resistance to endogenous RNase activity,circulating miRNAs have been proposed as diagnostic and prognostic biomarkers for various diseases,such as tumors,cardiovascular and autoimmune diseases.In this review,we summarized the role of some miRNAs in brain AVMs pathogenesis and discussed their potential cdinical appliation as non-invasive biomarkers.

Systemic Hemodynamic Changes in Low-Dose Ethanol Embolotherapy for Soft-Tissue Arteriovenous Malformations

Background Ethanol embolotherapy is considered an optimal choice for the treatment of arteriovenous malformations(AVMs);however,there are some complications associated with this treatment.This study aimed to prospectively investigate systemic hemodynamic changes in high-flow AVMs using ethanol embolotherapy.Methods From September 2012 to September 2014,34 male patients and 26 female patients with AVMs who underwent embolotherapy(100 sessions in total)with absolute ethanol were included in this study.Invasive systolic blood pressure(SBP)and heart rate(HR)were recorded before and after each injection and throughout the procedure.Differences between the initial and highest SBP(ΔmaxSP)and HR values(ΔmaxHR),as well as the initial and final SBP(ΔSP)and HR(ΔHR)values,were analyzed.We aimed to explore the potential association between these values and the amount of ethanol that was used.Results The total ethanol used was variable(0.01–0.40 mL/kg;mean,0.20 mL/kg).SBP and HR increased after ethanol injection in most sessions(91 in 100 sessions).SBP decreased in 9 sessions(9 in 100 sessions),while HR,oxygen saturation,and end-tidal CO2 decreased in one of the 9 sessions.ΔmaxSP andΔmaxHR averaged 38.4 mmHg and 27.8 bpm,respectively(both P<0.05),whileΔSP andΔHR averaged 3.4 mmHg and 4.0 bpm,respectively(both P<0.05).ΔmaxSP andΔmaxHR were positively correlated with the total dose of ethanol injected.Conclusions Elevations in SBP and HR during ethanol embolotherapy are common,temporary,and most likely pain-mediated;these increases tend to be positively correlated with ethanol dose.Hypotension may be regarded as an acute complication of ethanol embolotherapy.Hypotension combined with bradycardia,oxygen desaturation,and decreased end-tidal CO2 may be a potential predictor of cardiovascular collapse.

Combined Endovascular and Surgical Treatment for Brain Arteriovenous Malformations in Biplanar Hybrid Operating Room

Objective Combined surgical and endovascular treatment for vascular disorders has become prevalent in recent years.However,reports on one-session hybrid surgery for arteriovenous malformations(AVMs)are relatively rare.The safety and efficiency of combined treatment for brain AVMs were analyzed in biplanar hybrid operating room(OR)at one stage.Methods We retrospectively analyzed 20 patients with AVMs undergoing combined surgical and endovascular treatment from October 2015 to June 2018.The data for resection rate,microcatheter adhesion,surgical position and postoperative outcomes were analyzed.Total resection or near-total resection was achieved in all cases.Results A total of 13 patients were under combined endovascular and surgical procedures,and 7 experienced surgery with intraoperative digital subtraction angiography.Sitting position was applied in 3 of them;2 niduses in cerebellum,and 1 in parietal lobe.Compared with admission modified Rankin Scale(mRS)in all patients,postoperative 12-month mRS showed a significant decline.Besides,3 patients experienced microcatheter adhesion after endovascular embolization,thereafter underwent surgical adhesion removal while nidus resection was done.Conclusion Combined endovascular and surgical modality in a hybrid OR at one stage provides a safe strategy for the treatment of AVMs.The biplanar hybrid neurointerventional suite is endowed with unconstrained operating angle which enables combined endovascular and surgical treatment in sitting position.It also reduces the risk of microcatheter adhesion,which enables interventional radiologists to perform aggressively.

Percutaneous Transluminal Embolization with Coils-Treatmentof Pulmonary Arteriovenous Malformations

The clinical values of coils em boliztion in the treatm ent of pulm onary arteriovenous m alformations (PAVM ) and related complications were investigated.Eleven patients with PAVMs verified by pulm onary arterial angiography were treated by transcatheter coils em boliza- tion.Chest X- ray(11cases) ,com puter tomography(7cases) and/ or magnetic resonance im aging (2 cases) were performed before embolization.Blood- gas analysis was done in5 cases before and after em bolization.The follow- up materials of8patients were collected to evaluate the effect of em bolization with coils.The clinical m anifestations included cerebral em bolus,hem optysis and de- creased oxygenation in 9patients and the remaining 2 had no sym ptoms.9/ 11cases were found by chest X- ray and 8were diagnosed definitely.7/ 7,2 / 2 cases were diagnosed by CT or MR and di- agnosis was m ade in all cases.Embolization was perform ed in 2 9vessels.Partial pressure of oxy- gen in arterial blood of5 cases changed significantly before and after embolization.Slight com pli- cations occurred in 6 patients,such as low fever,chest pain,pleurisy.The follow- up results showed that7cases were cured effectively.No primary and secondary device migration,and no m edical paradoxical em bolization occurred.It was concluded thatcoils em boliztion is a well- estab- lished m ethod for treating PAVMs.It is a m inimally invasive lung preserving treatment with high efficiency and less com plication.

Bleomycin inhibits CLEC14A to attenuate the progression of extracranial arteriovenous malformations

Background:We previously reported that interstitial injection of bleomycin(BLM)reduces the size of early-stage extracranial arteriovenous malformation(AVM).Here,we sought to investigate the potential mechanism of BLM in treating extracranial AVM.Methods:Samples of human extracranial AVM(n=3)with no pharmacological treatment were harvested.AVM endothelial cells were isolated and cultured in primary cell culture.The transcriptome was examined using RNAsequencing,and differentially expressed C-type lectin domain family 14 member A(CLEC14A)was validated at the transcriptomic and protein levels.Immunocytochemical staining of CLEC14A was performed in samples of human extracranial AVM,with and without BLM treatment.Results:Through second-generation sequencing,we found that the expression of 5689 genes were differentially increased or decreased following 24-h BLM stimulation.We found that CLEC14A may play an important role in the progression of AVM and can be inhibited by BLM treatment.Conclusion:BLM inhibited CLEC14A expression to attenuate the progression of AVM.

Uterine Arteriovenous Malformations: Therapeutic Strategies and the Place of Hysteroscopy

Uterine arteriovenous malformations (UAVMs) are not common and are not well known. They are mainly manifested by hemorrhages that can be life-threatening. Their diagnosis is based mainly on ultrasound coupled with Doppler flow, as well as pelvic magnetic resonance imaging and angiography. In the absence of a consensus, and based on our experience, we discuss the place of hysteroscopy in the therapeutic strategy of UAVM. We reported 3 cases of UAVM, and we performed a review of the literature concerning the diagnosis and treatment of this pathology. We finally collected the advantages of the embolization-hysteroscopy sequence. In fact, the data suggest that hysteroscopy is a feasible and safe alternative treatment modality for UAVM. We believe that the resection of UAVM can be done under optimal conditions with a reduced risk of bleeding. Hysteroscopy would allow for optimal evaluation of the uterine cavity after treatment as well as the possibility of applying an anti-adhesive gel. In addition, the combination of hysteroscopy and embolization would require less healing time and shorter follow-up than embolization alone. It could also reduce the number of patients lost to follow-up.

Estimation of Treatment Benefit in Patients with Cerebral Arteriovenous Malformations

Background: Cerebral arteriovenous malformations (AVMs) are vascular lesions that may be associated with a significant morbidity and mortality. There is still today no consensus regarding treatment of unruptured AVMs. Using known data from the literature, and data from our own institution concerning stereotactic radiotherapy, our aim was to construct an equation that may be used to evaluate the benefit of intervention vs. conservative treatment in unruptured AVMs. Methods: Assuming an annual bleeding risk of 4% and previously reported mortality (29%) and morbidity (16%) rates after a bleeding from an AVM, an equation was constructed. This equation would estimate the time until the combined mortality and morbidity associated with conservative treatment would equal the mortality and morbidity of stereotactic radiotherapy. Results: Using stereotactic radiotherapy this treatment would benefit over conservative treatment in excess of 8.12 years. The risk of bleeding was the most important factor influencing the benefit of intervention vs. conservative treatment. Conclusions: We argue that that it may be possible to estimate the benefit of intervention vs. conservative treatment in an unruptured AVM. This may be achieved using our proposed equation and data specific to each center performing treatment for AVMs.

Intralesional Interstitial Injection of Bleomycin for Management of Extracranial Arteriovenous Malformations in Children

Background Despite many advances in the treatment for extracranial arteriovenous mal­formations(AVMs),they still result in tedious dissection and potential unacceptable com­plications,particularly in children.Therefore,this study aimed to investigate the efficacy and safety of intralesional interstitial injection of bleomycin for the treatment of children with AVMs.Methods A total of 10 children(6 boys and 4 girls)with AVMs were treated with serial interstitial bleomycin injections between May 2014 and January 2017.Maximum single doses of 15 U and 1 U/kg per session were administered for six sessions at a 1-month inter­val.Therapeutic effectiveness was evaluated and classified into four categories:complete response(CR),partial response(PR),no response,and worsening at 3 months after the last session.Further clinical follow-up outcomes were classified as improved,stable,or aggra­vated.Adverse events were recorded according to the Society of Interventional Radiology classification.Results All 10 children completed the sessions and follow-ups.CR occurred in 3(30%)patients,PR in 6(60%),and no response in 1(20%).Minor complications(class A)included maculopapular rash,bulla,vomiting,and hyperpigmentation,whereas no major complications occurred.Conclusion Intralesional interstitial injection of bleomycin is a feasible approach for the treatment of AVMs in children and provides safe and effective outcomes.This method may be an earlier treatment alternative in children to prevent potential destructive progression,considering the serious complications of currently available therapeutic methods.

Endovascular embolization of pulmonary arteriovenous malformations

Background The major consequence of pulmonary arteriovenous malformations （PAVMs） is the direct inflow of blood from the pulmonary artery to the pulmonary vein which induces hypoxemia. Severe complications include transient ischemic attacks, paradoxical embolization in the central nervous system, massive hemoptysis or hemothorax, etc. The conventional treatment is surgical intervention. However, this can be very traumatic and dangerous. Endovascular embolization has advantages over surgery such as a faithful therapeutic effect, a low complication rate, repeatability, etc. Methods Patients （n=-23） with symptomatic PAVMs underwent endovascular embolization; 11 were males and 12 were females, with ages ranging from 6 months to 58 years. During the embolization, microcoils were applied in 6 cases and standard steel coils were used in 17 cases. Results Multiple PAVMs lesions were found in 16 cases and single PAVMs lesion was found in 7 cases. Embolotherapy was carried out 28 times for 23 patients. The success rate was 100%. The results of pulmonary arteriography after treatment showed that single lesion disappeared completely while the main abnormal vessels in multiple lesions also disappeared. The mean blood oxygen saturation increased from （78.04＋8.22）% to （95.13＋3.67）% after the procedure. A correlated groups t test showed changes in blood oxygen saturation before and after embolization （t=9.101, P 〈0.001）. Symptoms of cardiac insufficiency disappeared in 5 cases and vascular murmur in the chest disappeared in 13 cases. After embolization, mild chest pain occurred in 11 cases, small amounts of pleural effusion occurred in 5 cases, and 1 patient died 2 months later because of a pyogenic infection secondary to the pulmonary infarction. Among the 22 remaining cases, with overall follow-up ranging from 18 months to 12 years, general conditions were fine, daily lives were normal and there were no neurologic symptoms or signs, except for 3 patients with diffused PAVMs who had persistent blood oxygen saturation between 85% and 90%. Symptoms of hypoxia never recurred in the other cases. Conclusions Endovascular embolization of pulmonary arteriovenous malformations can significantly improve blood oxygen saturation and reduce serious complications such as cerebral infaction. Therefore, this kind of interventional procedure is a safe and effective treatment method with a low complication rate.

Diagnostic value of contrast-enhanced intraoperative Doppler sonography for cerebral arteriovenous malformations compared with angiography

Background Intraoperative Doppler sonography has been used in the neurosurgical operating room for the localization and description of cerebral arteriovenous malformations （AVMs）. This study aimed to investigate the clinical value of contrast-enhanced intraoperative Doppler sonography, including its ability to assess the location and identify of feeding arteries in patients with AVMs and to compare this method with angiography.Methods Twenty-three patients with cerebral AVMs who were diagnosed using angiography, were examined with contrast-enhanced intraoperative Doppler sonography. As an echo-enhancing agent, Sulphur Hexafluoride Microbubbles for Injection （＂SonoVue＂） was administered intravenously in all patients. Sonogram results were reviewed and correlated with angiographic findings. For statistical analysis, the Wilcoxon signed-rank test was applied.Results Angiography identified 20 AVM lesions in the anterior or middle fossa and 3 in the posterior fossa.Contrast-enhanced intraoperative Doppler was somewhat less sensitive for only detecting 21/23 （91.3%） of the AVM lesions. Additionally, contrast-enhanced intraoperative Doppler slightly underestimated AVM size compared with angiographic findings but showed feeding arteries with sufficient acoustic properties. In 15 patients, angiography revealed a coincidental blood supply from another intracranial vessel, which was missed by contrast-enhanced intraoperative Doppler sonography.Conclusions In a limited group of patients with AVMs, contrast-enhanced intraoperative Doppler sonography was a less sensitive but useful and simple method for the detection of AVMs in contrast to angiography. No specific untoward effects were attributed to the use of ＂SonoVue＂ as a contrast-enhancing substance.

Endovascular treatment of cerebral arteriovenous malformations with Onyx embolization

Background In the past 5 years, new treatment materials and techniques offering a different concept in endovascular treatment have been described for cerebral arteriovenous malformations （CAVMs）. The aim of this study was to assess the endovascular treatment of CAVMs by using a liquid embolic material, Onyx （ Micro Therapeutics. Inc. , Irvine, CA, USA）. Methods From September 2003 to September 2004, Onyx was used to treat 22 patients with CAVMs. Ten AVMS were located in functional areas, 8 in deep cerebral areas, and 4 in the cerebellar hemisphere. The size of CAVMs was about 3 cm in diameter in 5 patients, 3 -6 cm in 11, and more than 6 cm in 6. Results In the 22 patients, Onyx embolization was successful. Nidus occlusion was complete in 3 patients, 〉 90% in 8, 〉 80% and 〈 90% in 6, and 〉 50% and 〈 80% in 5. Complications included transient neurological deficits in 2 patients, and adherence of microcatheter to the site of injection in 2. Conclusions Being non-adhesiveness, Onyx is a safe and satisfactory embolic material in the treatment of CAVMs. But its long-term efficacy awaits further follow-up.

Embolization of brain arteriovenous malformations with ethylene vinyl alcohol copolymer： technical aspects

Background Endovascular therapy plays an important role in the treatment of brain arteriovenous malformations （BAVMs）. Ethylene vinyl alcohol copolymer （Onyx） is a novel liquid embolic material. This study aimed to summarize our experience of using Onyx for embolization of BAVMs with the focus on embolization technique. Methods From September 2003 to November 2007, 115 patients （43 women and 72 men, with a mean age of 29 years） with BAVMs were endovascularly treated with Onyx in our department. The following features of all AVMs were evaluated prior to treatment： type of nidus and shunt, draining veins, and feeding arteries. A total of 196 endovascular procedures were performed. Results The course of endovascular treatment was completed in 88 patients. Additional sessions were planned in 27 patients. Of the 88 patients, total occlusion was obtained in 23 patients （26.1%）, near-total （〉80% of the original volume） occlusion was obtained in 35 patients （39.8%） and partial occlusion （〈80% of the original volume） was obtained in 30 patients （34.1%） using embolization as the sole therapeutic technique. Mean volume reduction was 72% （range 30%-100%） in 115 patients. Thirty four patients （38.6%, 34/88） underwent radiosurgical treatment. Additional embolization sessions were planned in 27 patients. Complications occurred in 19 patients （16.5%, 19/115）, leading to death in one patient （mortality 0.9%） and permanent disabling in 3 patients （morbidity 2.6%）. Conclusions Onyx was shown to be feasible and safe for embolization of BAVMs. Proper use of the Onyx injection technique largely improved the endovascular treatment of BAVMs. Large AVMs can be adequately reduced in size through the use of additional treatment.