Use of near infrared spectroscopy for the prediction of perioperative complications in patients undergoing elective microsurgical resection of cerebral arteriovenous malformations- a prospective observational trial (NIRSCAM trial)

PURPOSE

Cerebral arteriovenous malformations (AVM) represent focal abnormal areas of low resistance circulation which render the peri-nidal neuronal tissue susceptible to ischemia. The post-excision cerebral perfusion surge can result in hyperaemic complications.We hypothesised that Near Infrared Spectroscopy (NIRS)-guided perioperative management can aid in the prediction and prevention of perioperative complications in patients presenting for surgical excision of cerebral AVMs. We also intended to identify a threshold value of regional cerebral oxygen saturation (rScO2) to predict the incidence of perioperative complications.

METHODS

This was a prospective observational study involving patients undergoing elective supratentorial AVM resection surgeries. Intraoperative rScO2 and hemodynamic monitoring were done and continued for postoperatively for 12 h. Any drift in rScO2 by > 12% from baseline was managed as per study protocol and perioperative adverse events were recorded and analyzed. Post surgery,for analytical purpose patients were categorized into two groups, Group A - patients without complications and Group B - patients who had complications postoperatively.

RESULTS

Twenty-five patients presenting for surgical excision of cerebral AVM were recruited for this study of which 9 patients had postoperative adverse events and were allocated to group B. The ipsilateral mean rScO2 at the time of complication (Pc) was significantly lower in Group B than in group A [62.08 ± 9.33 vs.70.52 ± 7.17; p = 0.04]. The mean ipsilateral rScO2 drift from N2- N5 (i.e., post excision) was significantly higher in Group B than in Group A [12.01 ± 2.63% vs. 4.98 ± 5.7%;p = 0.02]. Mean ipsilateral rScO2 Drift ratio (N5 :N2) was significantly higher in group B as compared to group A [1.32 ± 0.01 vs. 1.01 ± 0.06;p < 0.001]. In the immediate post excision phase, the ipsilateral mean rScO2 was significantly higher in Group B at the post excision time point compared to Group A [ 83.03 ± 6.08 vs. 73.52 ± 7.07;p < 0.01)]. The mean ipsilateral rScO2 drift from N1-N6 (i.e., postoperatively) was significantly higher in Group B as compared to Group A [14.96 ± 0.080% vs. 6.88 ± 4.5% ; p < 0.01]. Similarly, the Mean Ipsilateral rScO2 Drift ratio (N6:N1) was significantly lower in group B as compared to group A [2.17 ± 0.02 vs. 1.05 ± 0.03 ;p < 0.0001].

CONCLUSIONS

In patients undergoing cerebral AVM resection, a post-resection ipsilateral rScO2 increase by > 12% with a drift ratio of > 1.3 could signify cerebral hyperemia. A postoperative ipsilateral rScO2 drift > 14.5% with a drift ratio of 2.1 from the baseline is associated with postoperative complications in our study. Further multi-centric randomized control trials are needed to support our research findings.

Deliberately Staged Combined Endovascular Embolization and Subsequent Microsurgery Resection for the Treatment of Cerebral Arteriovenous Malformations

OBJECTIVE

Complex cerebral arteriovenous malformations (AVMs) require a combined therapy of endovascular embolization and microsurgical resection to eliminate the lesion and maximize neurological protection, while a deliberate time interval might contribute to optimal clinical outcomes. The present study aimed to explore the feasibility of this paradigm.

METHODS

All patients who underwent deliberately planned presurgery embolization and microsurgery resection between 2015 and 2023 were reviewed, with baseline data, postoperative complications, and follow-up outcomes recorded. The modified Rankin scale (mRS) was used to evaluate clinical outcomes, with mRS 0-2 defined as good.

RESULTS

A total of 30 patients were included in the study (15 were ruptured AVMs). The median Spetzler-Martin grade of baseline AVMs was 3 (interquartile range: 2-3). The median interval between the last embolization and microsurgery was 5 days (interquartile range: 2.25-7). The complete removal rate was 100%, and the overall permanent complication rate was 16.67%. At the last follow-up, 26 patients achieved mRS 0-2, while 28 had improved or unaltered mRS. The last follow-up mRS significantly improved from baseline and discharge (P = 0.0006 and P = 0.006). The last follow-up mRS decreased by 0.65 for each additional day of time interval before the 4.4-day inflection point (β = -0.65, P = 0.02) in the AVM ruptured cohort.

CONCLUSIONS

The deliberately staged combined procedure of embolization and microsurgery might be a safe and efficacious strategy for Spetzler-Martin grade 2-5 AVMs, 4-5 days might be an appropriate staged time interval for ruptured AVMs, although further studies are needed to substantiate these findings.

Comparison Between the Stereoscopic Virtual Reality Display System and Conventional Computed Tomography Workstation in the Diagnosis and Characterization of Cerebral Arteriovenous Malformations

It is difficult to accurately understand the angioarchitecture of cerebral arteriovenous malformations (CAVMs) before surgery using existing imaging methods. This study aimed to evaluate the ability of the stereoscopic virtual reality display system (SVRDS) to display the angioarchitecture of CAVMs by comparing its accuracy with that of the conventional computed tomography workstation (CCTW). Nineteen patients with CAVM confirmed on digital subtraction angiography (DSA) or during surgery were studied. Computed tomography angiography images in the SVRDS and CCTW were retrospectively analyzed by two experienced neuroradiologists using a double-blind method. Angioarchitectural parameters, such as the location and size of the nidus, type and number of the arterial feeders and draining veins, and draining pattern of the vessels, were recorded and compared. The diameter of the nidus ranged from 1.1 to 9 cm. Both CCTW and SVRDS correctly diagnosed the location of the nidus in 19 patients with CAVM. Among the 19 patients, 35 arterial feeders and 25 draining veins were confirmed on DSA and during surgery. With the DSA and intraoperative results as the gold standard bases, the CCTW misjudged one arterial feeder and one draining vein and missed three arterial feeders and two draining veins; meanwhile, the SVRDS missed only two arterial feeders. SVRDS had some advantages in displaying nidus, arterial branches, and draining veins of the CAVM compared with CCTW, as well as SVRDS could more intuitively display the overall angio-architectural spatial picture of CAVM.

Unruptured cerebral arteriovenous malformation in children: Outcome in treated and untreated patients

BACKGROUND

The management of unruptured cerebral arteriovenous malformation (URCAVM) is highly controversial; however, data regarding URCAVM in children are scarce.

MATERIAL AND METHODS

We retrospectively reviewed consecutive children followed for URCAVM in our department between 2001 and 2021.

RESULTS

Out of 36 patients, 12 were initially managed by observation, and 24 underwent first-line treatment: 8 by microsurgery, 10 by radiosurgery, 2 by embolization, and 4 by combined treatment. Mean follow-up of the whole group was 63months. Complete cure of the malformation was obtained in 14 patients (58%) in the treatment group: 8/8 in the microsurgery group, 5/10 in the radiosurgery group, 1/4 in the combined treatment group, and none in the embolization group. Two of the initially non-treated patients presented cerebral hemorrhage, with significant neurological consequences. In the treatment group, 5 patients presented new neurological deficits, only 1 of which, however, was functionally significant. Headache improved in 11 cases, mostly in the treatment group. Overall, 6 patients in the treatment group became asymptomatic, versus none in the observation group.

CONCLUSIONS

The treatment of URCAVM is a reasonable option in many pediatric cases, considering the cumulative risk of cerebral hemorrhage during the child's lifetime, as well as the symptoms specific to URCAVM. Microsurgery, when feasible, offers the best functional results and control of the AVM; however, the risk-benefit ratio should be weighed on a case-by-case basis. More studies will be needed to inform treatment decisions in pediatric URCAVM.

The Era of Onyx Embolization: A Systematic and Literature Review of Preoperative Embolization Before Stereotactic Radiosurgery for the Management of Cerebral Arteriovenous Malformations

INTRODUCTION

The current treatment paradigm for intracranial arteriovenous malformations (AVMs) focuses on reducing the risk of intracranial hemorrhage using various therapeutic means including embolization, stereotactic radiosurgery (SRS), and microsurgical resection. To improve AVM obliteration rates with SRS, pre-radiosurgical embolization has been trialed in a number of studies to reduce the volume of the AVM nidus prior to radiosurgery. This study aimed to review the efficacy of pre-radiosurgical embolization in the pre-Onyx era compared to the current Onyx era.

METHODS

A systematic review was performed using PubMed to identify studies with 20 or more AVM patients, embolization material, and obliteration rates for both embolization + stereotactic radiosurgery (E+SRS) and SRS-only groups.

RESULTS

Seventeen articles consisting of 1133 eligible patients were included in this study. A total of 914 (80.7%) patients underwent embolization prior to SRS. Onyx was used as the embolysate in 340 (37.2%) patients in the E+SRS cohorts. Mean obliteration rate for the embolized cohort was 46.9% versus 46.5% in the SRS-only cohort. When comparing obliteration rates based on embolysate material, obliteration rate was 42.1% with Onyx+SRS and 50.0% in the non-Onyx embolysate + SRS cohort.

CONCLUSIONS

Onyx (ethylene vinyl-alcohol copolymer dissolved in dimethyl sulfoxide and suspended in micronized tantalum powder) has been increasingly used for the embolization of intracranial AVMs with increased success regarding its ease of use from a technical standpoint and performs similarly to other embolysate materials.

Multiple brain arteriovenous malformations: systematic review and individual patient data meta-analysis

Multiple brain arteriovenous malformations (bAVM) are rare neurovascular lesions usually related to genetic syndromes. Its management is not well established given its rarity. The objective of this study was to describe the clinical and angiographic features of published cases and to explore their associations with treatment outcomes. We performed a literature search of published cases in Medline and the Regional Index Medici. Additional cases were searched in our single-center registry. Data on the proportions of patients and clinical and angiographic characteristics were extracted. The study outcomes were nidal instability in patients who underwent staged treatment and radiological cure in patients who underwent treatment using any treatment modality. Logistic regression models for the study outcomes were analyzed. Data on the proportions of multiple bAVM patients were summarized with meta-analyses of proportions. We included 118 patients (reported in 68 studies) from the literature and 6 cases identified in our registry. A total of 124 patients harboring 339 bAVM nidi were included in the analyses. Differences between syndromic and non-syndromic cases were observed. The logistic regression analyses showed that angiographically occult untreated bAVM was associated (OR 14.37; 95% CI 2.17 to 95.4) with nidal instability after staged treatment, and deep (OR 5.11; 95% CI 1.51 to 17.27) and eloquent (OR 3.91; 95% CI 1.22 to 12.52) locations were associated with residual disease after treatment. Inconsistent reporting of relevant data throughout the included studies undermined the planned analyses. Some prognostic factors were found to be related to the study outcomes. Study Registration: The protocol of the systematic review was registered in PROSPERO as CRD42021245814.

The micro-pathological characteristics in cerebral arteriovenous malformations(cAVMs)

BACKGROUND

Rupture and hemorrhage is the most serious complication of cerebral arteriovenous malformation(cAVMs), and have a significant impact on quality of life.

OBJECTIVES

We investigated the hematoxylin and eosin staining and ultrastructural features of cAVMs and characterized the abnormal vascular structure of cAVMs.

METHODS

Light and electron microscopy were performed on a series of pathological specimens obtained from 12 patients with cAVMs who underwent surgical resection for the first time without radiosurgery or embolization therapy.

RESULTS

In tunica intima, we found that the vascular endothelial cells of cAVMs were damaged, and the lysis of the cell body occurred in multiple regions. In tunica media, the arrangement of the elastic layer was disordered, and the thickness was uneven. Part of the structure of the elastic lamina was missing. The part of tunica adventitia was fractured and discontinuous. In addition, we also observed the phenomenon that different blood vessels share the same vascular wall. Macrophage phagocytosis and lymphocyte infiltration in the adventitial region of ruptured cAVMs. Abnormal lipid deposition in vascular endothelial cells and smooth muscle cells.

CONCLUSIONS

The structural incompleteness of cAVMs may be an important cause of hemorrhage.

Efficacy of Utilizing Both 3-Dimensional Multimodal Fusion Image and Intra-Arterial Indocyanine Green Videoangiography in Cerebral Arteriovenous Malformation Surgery

OBJECTIVE

An understanding of the complex morphology of an arteriovenous malformation (AVM) is important for successful resection. We have previously reported the utility of intra-arterial indocyanine green (ICG) videoangiography for this purpose, but that method cannot detect the angioarchitecture covered by brain tissue. 3-dimensional (3D) multimodal fusion imaging is reportedly useful for this same purpose, but cannot always visualize the exact angioarchitecture due to poor source images and processing techniques. This study examined the results of utilizing both techniques in patients with AVMs.

METHODS

Both techniques were applied in 12 patients with AVMs. Both images were compared with surgical views and evaluated by surgeons.

RESULTS

Although evaluations for identifying superficial feeders by ICG videoangiography were high in all cases, the more complicated the AVM, the lower the evaluation by 3D multimodal fusion imaging. Conversely, evaluation of the estimated range of the nidus was high in all cases by 3D multimodal fusion imaging, but low in all but one case by ICG videoangiography. Nidus flow reduction was recognized by Flow 800 analysis obtained after ICG videoangiography.

CONCLUSIONS

These results showed that utilizing both techniques together was more useful than each modality alone in AVM surgery. This was particularly effective in identifying superficial feeders and estimating the range of the nidus. This technique is expected to offer an optimal tool for AVM surgery.

Long-term follow-up in patients with brain arteriovenous malformation based on the Quality of Life Scale and socioeconomic status

OBJECTIVE

Intracranial haemorrhage (ICH) is associated with permanent neurological disability resulting in deterioration of the quality of life (QoL). Our study assesses QoL in patients with ruptured arteriovenous malformation (AVM) in long-term follow-up at least five years after ICH and compares their QoL with the QoL of patient with non-ruptured AVM.

METHODS

Using the Quality of Life Scale (QOLS), the Patient Health Questionnaire (PHQ-9) for depressive symptoms, and the socioeconomic status (SES), a prospective assessment was performed. The modified Rankin Scale (mRS) was assessed for outcome.

RESULTS

Of 73 patients, 42 (57.5%) had ruptured (group 1) and 31 (42.5%) a non-ruptured AVM (group 2). Mean follow-up time was 8.6 ± 3.9 years (8.5 ± 4.2 years in group 1 and 8.9 ± 3.7 years in group 2). Favourable outcome (mRS 0-1) was assessed in 60 (83.3%) and unfavourable in 12 (16.7%) patients. Thirty-one of 42 patients (73.8%) in group 1 and 29 of 30 patients in group 2 (96.7%) had favourable outcomes. Mean QOLS was 85.6 ± 14.1 (group 1 86.1 ± 15.9, group 2 84.9 ± 11.4). Patients in group 1 did not show a significant difference in QoL compared to patients in group 2 (p = 0.23). Additional analyses in group 2 (rho =  - 0.73; p < 0.01) and in untreated AVM patients (rho =  - 0.81; p < 0.01) showed a strong correlation between QOLS and PHQ-9.

CONCLUSION

Long-term follow-up showed no difference in the QoL between patients with and without ICH caused by brain AVM. Outcome- and QoL-scores were high in both groups. Further studies are necessary to evaluate depression and anxiety symptoms in patients with AVM.

Evaluation of theTherapeutic Effect of the Hybrid Operation on Patients with Aneurysms Associated with Cerebral Arteriovenous Malformations with different Redekop Classifications

BACKGROUND

Intracranial aneurysms associated with cerebral arteriovenous malformations (AVMs) are a rare condition in the clinic, and treatment is very difficult due to their particular anatomical features. We present our experience in the treatment of intracranial aneurysms with AVMs and evaluate the effectiveness and safety of endovascular treatment combined with microsurgical resection (the hybrid operation).

METHODS

This was a single-center retrospective study in our neurosurgical department from January 2015 to January 2021. We collected clinical data from 48 patients with intracranial aneurysms associated with AVMs and categorized them according to Redekop classifications according to the results of cerebral imaging examination to compare the therapeutic effects of endovascular embolization and the hybrid operation.

RESULTS

Compared to nonaneurysmal AVMs, intracranial aneurysms with AVMs more often presented with intracranial hemorrhage (P<0.05). Massive hematoma and severe neurological impairment were more often found in patients with intracranial aneurysms with AVMs (P<0.05). For flow-related aneurysms, the hybrid surgery had a higher one-stage cure rate than endovascular embolization alone (P<0.05). Both treatment methods had similar effects on intranidal aneurysms (P>0.05). There were no significant differences in prognostic indicators between the two treatments. However, the recurrence rate of AVMs with proximal flow-related aneurysms was lower in patients who underwent the hybrid operation (P<0.05).

CONCLUSION

The hybrid operation was safe and effective for patients with intracranial aneurysms associated with AVMs. For flow-related aneurysms, the one-stage cure rate was higher and the recurrence rate was lower with the hybrid operation than with endovascular embolization alone.

Cerebral arteriovenous malformation and foreign accent syndrome: a case report

OBJECTIVE

This case study aims to present the Foreign Accent Syndrome (FAS) in a patient with Cerebral Arteriovenous Malformation (cAVM), considering neuropsychological, radiological and microsurgical aspects.

METHODS

The patient underwent preoperative neuropsychological assessment and MRI and Tractography were performed to identify fibers close to the lesion site. In the surgical procedure, a craniotomy was performed for excision of the cAVM. After surgery and 6 months after the surgical procedure, the patient underwent further and neuropsychological evaluations.

RESULTS

The presence of AVM located in the posterior part of the medial surface of the left superior frontal gyrus was identified and the neuropsychological evaluation found cognitive deficits and symptoms characteristic of FAS, which disappeared after resection.

CONCLUSION

This report presented a case of cAVM in which symptoms were found even without rupture, which was no longer observed after the surgical procedure, demonstrating the relationship of cAVM with the symptoms and neuroanatomical bases of FAS.

Predictors of seizure control in patients with cerebral arteriovenous malformation

PURPOSE

We aimed to define the predictors of a 2-year seizure-free outcome among patients with cerebral arteriovenous malformation (AVM).

METHODS

A retrospective cohort study recruited patients diagnosed with AVM admitted in the hospital between 2002 and 2020. The demographic data, clinical presentations, seizure semiology, neuro-imaging findings, modality of treatment, and clinical outcomes were compared between the 2-year seizure-free and non-2-year seizure-free groups. A logistic regression model was applied to determine the significant predictors of a 2-year seizure-free outcome.

RESULTS

Of 372 radiologically confirmed patients with cerebral AVM, 105 (28.23%) experienced seizure and a 2-year seizure-free outcome was achieved in 76.19%. Most seizures presented as the initial symptom. Generalized onset seizure was the most common seizure semiology. A nidus diameter < 3 cm (adjusted odds ratio [aOR] 3.102; 95% CI 1.129-9.683; p = 0.046) was the independent predictor of a 2-year seizure-free period, whereas underlying epilepsy (aOR 0.141; 95% CI 0.010-0.688; p = 0.015) was an independent predictor against a 2-year seizure-free outcome.

CONCLUSION

A nidus diameter < 3 cm was the independent predictor of a 2-year seizure-free outcome, whereas underlying epilepsy was the factor against a 2-year seizure-free outcome.

Gamma knife radiosurgery cured hydrocephalus in non-hemorrhagic brain stem arteriovenous malformation

A 13-year-old boy, with a history of intermittent headache and transient diplopia, was found to have non-hemorrhagic cerebral arteriovenous malformation in the midbrain tegmental region associated with hydrocephalus. Gamma knife radiosurgery was performed at 16 Gy with 75% marginal dose. Posttreatment course was uneventful. Follow-up MR imaging at one year after the treatment revealed complete disappearance of the abnormal vascular flow voids. The size of each ventricle at the treatment and at one year after treatment were as follows; 60.2 cc and 20.9 cc in the lateral ventricles, 3.7 cc and 2.7 cc in the third ventricle. The hydrocephalus might be caused by obstructive mechanism but mostly by high venous pressure due to the shunt blood flow. The goal of treatment for hydrocephalus should be nidus obstruction and normalizing the vascular flow.

A low-grade cerebral arteriovenous malformation suspected of being a metastatic tumor: A case report and literature review

Cases of low-grade cerebral arteriovenous malformations (cAVMs) showing dynamic changes and large areas of brain edema on short-term MRI follow-up have rarely been reported. This report describes an incidentally discovered and initially misdiagnosed cAVM in a patient with malignancies. The presence of abnormal signals surrounded by large areas of brain edema combined with tortuous or dilated vessels indicates the possibility of an AVM, especially in young people.

Segmentation techniques of brain arteriovenous malformations for 3D visualization: a systematic review

BACKGROUND

Visualization, analysis and characterization of the angioarchitecture of a brain arteriovenous malformation (bAVM) present crucial steps for understanding and management of these complex lesions. Three-dimensional (3D) segmentation and 3D visualization of bAVMs play hereby a significant role. We performed a systematic review regarding currently available 3D segmentation and visualization techniques for bAVMs.

METHODS

PubMed, Embase and Google Scholar were searched to identify studies reporting 3D segmentation techniques applied to bAVM characterization. Category of input scan, segmentation (automatic, semiautomatic, manual), time needed for segmentation and 3D visualization techniques were noted.

RESULTS

Thirty-three studies were included. Thirteen (39%) used MRI as baseline imaging modality, 9 used DSA (27%), and 7 used CT (21%). Segmentation through automatic algorithms was used in 20 (61%), semiautomatic segmentation in 6 (18%), and manual segmentation in 7 (21%) studies. Median automatic segmentation time was 10 min (IQR 33), semiautomatic 25 min (IQR 73). Manual segmentation time was reported in only one study, with the mean of 5-10 min. Thirty-two (97%) studies used screens to visualize the 3D segmentations outcomes and 1 (3%) study utilized a heads-up display (HUD). Integration with mixed reality was used in 4 studies (12%).

CONCLUSIONS

A golden standard for 3D visualization of bAVMs does not exist. This review describes a tendency over time to base segmentation on algorithms trained with machine learning. Unsupervised fuzzy-based algorithms thereby stand out as potential preferred strategy. Continued efforts will be necessary to improve algorithms, integrate complete hemodynamic assessment and find innovative tools for tridimensional visualization.

How Reliable Is the Intraoperative Computed Tomography Angiography in Assessing Complete Surgical Resection of Cerebral Arteriovenous Malformations?

BACKGROUND

Digital subtraction angiography (DSA) is still considered the gold standard test to evaluate arteriovenous malformation's (AVM) residual after microsurgical resection.

OBJECTIVE

To evaluate the safety and reliability of intraoperative computed tomography angiography (iCTA) as an immediate method of evaluating the surgical results of AVM resection.

METHODS

We performed a retrospective review for all cases of cerebral AVMs at our institute from January 2015 to April 2020 who underwent surgical resection of cerebral AVM and had iCTA. All included patients underwent a postoperative DSA, and the results were compared with iCTA.

RESULTS

Twenty-eight cases were included. All cases showed complete resection (100%) in the iCTA, and the results were consistent with the postoperative DSA results. The sensitivity of iCTA was 100%. The added operative time ranged from 25 to 30 min. There were no complications related to the use of iCTA.

CONCLUSION

Intraoperative assessment of AVMs surgical results with an iCTA is safe and reliable. The sensitivity of iCTA following AVM resection merits further investigations.

Spontaneous regression of a thrombosed cerebral arteriovenous malformation in a patient with a prothrombotic state associated with multiple myeloma: A case report and literature review

Background

Cerebral arteriovenous malformations (AVMs) are pathologic communications between veins and arteries of the brain vasculature. Its spontaneous regression is rare, and many factors have been described in the effort to explain this phenomenon, including a hypercoagulable state.

Case Description

We present the case of a spontaneous unruptured AVM regression in a patient where thrombosis of the malformation was found, probably due to a prothrombotic state associated with multiple myeloma (MM).

Conclusion

We aim to contribute to the study of this rare phenomenon, presenting the relationship between a hypercoagulable state caused by MM and the spontaneous AVM regression that has not been previously reported.

Involvement of Neutrophil Extracellular Traps in Cerebral Arteriovenous Malformations

BACKGROUND

Cerebral arteriovenous malformations (cAVMs) represent tangles of abnormal vasculature without intervening capillaries. High-pressure vascular channels due to abnormal arterial and venous shunts can lead to rupture. Multiple pathways are involved in the pathobiology of cAVMs including inflammation and genetic factors such as KRAS mutations. Neutrophil release of nuclear chromatin, known as neutrophil extracellular traps (NETs), plays a multifunctional role in infection, inflammation, thrombosis, intracranial aneurysms, and tumor progression. However, the relationship between NETs and the pathobiology of cAVMs remains unknown. We tested whether NETs play a role in the pathobiology of cAVMs.

METHODS

We analyzed samples from patients who had undergone surgery for cAVM and immunohistochemically investigated expression of citrullinated histone H3 (CitH3) as a marker of NETs. CitH3 expression was compared among samples from cAVM patients, epilepsy patients, and normal human brain tissue. Expressions of thrombotic and inflammatory markers were also examined immunohistochemically in samples from cAVM patients.

RESULTS

Expression of CitH3 derived from neutrophils was observed intravascularly in all cAVM samples but not other samples. Nidi of AVMs showed migration of many Iba-I-positive cells adjacent to the endothelium and endothelial COX2 expression, accompanied by expression of IL-6 and IL-8 in the endothelium and intravascular neutrophils. Unexpectedly, expression of CitH3 was not necessarily localized to the vascular wall and thrombus.

CONCLUSIONS

Our results offer the first evidence of intravascular expression of NETs, which might be associated with vascular inflammation in cAVMs.

Management of Acute Hemorrhage Caused by Cerebral Arteriovenous Malformation During Pregnancy-Case Series and Literature Review

OBJECTIVE

Acute hemorrhage caused by cerebral arteriovenous malformation (cAVM) during pregnancy is uncommon but life-threatening for both mother and fetus and presents a great challenge to clinical management. However, there is still no consensus on the treatment strategy and the treatment timing of acute hemorrhage from cAVM during pregnancy. The aim of this study was to amalgamate reported case series and our cases regarding the clinical management of pregnant patients under this special condition.

METHODS

We report a case series of 3 pregnant patients with acute hemorrhage caused by cAVM in our hospital. A systematic PubMed search of the English-language literature published between 1970 and 2020 was carried out. Clinical information including patients' age, gestational age, imaging studies, treatment strategy, treatment timing, delivery mode, and outcomes were collected and analyzed.

RESULTS

The rebleed rate is about 7.1% and the mortality from rebleeding is up to 25%. Treatment modalities included radical surgery, endovascular embolization, radiosurgery/stereotactic radiosurgery, palliative surgery, and conservative treatment. There were no maternal deaths in either the intrapartum intervention group and the postpartum intervention subgroup of gestational age <34 weeks.

CONCLUSIONS

A high rebleed rate and high mortality from rebleeding indicate that the intervention of ruptured cAVM should not be delayed. Intervention of ruptured cAVM within 2 weeks after initial hemorrhage is advisable in patients at gestational age <34 weeks, whereas termination of pregnancy as soon as possible followed by timely intervention of ruptured cAVM is practicable in patients at gestational age ≥34 weeks.

RNF213 rare variants and cerebral arteriovenous malformation in a Chinese population

OBJECTIVE

Cerebral arteriovenous malformation (AVM) is characterised by an abnormal tangle of arteries and veins, the rupture of which is a significant portion of the morbidity and mortality cases, especially in young populations. However, the exact risk factors and pathophysiologic mechanisms of AVM remain poorly understood. RNF213 variants have been identified as obvious susceptible factors of several cerebrovascular disorders, such as Moyamoya disease and intracranial aneurysms. Thus, this study aimed to determine whether there is an association between RNF213 rare variants and AVM.

METHODS

The AVM group included 22 patients with AVM. The control group included 1007 samples from the GeneSky in-house database and 208 samples from the 1000 Genome Project of Chinese Han Population. Genomic DNA samples were extracted from the peripheral blood of the AVM patients, and targeted exome sequencing of RNF213 was performed to assess the existence of low-frequency or rare variants. Sanger sequencing was performed to validate the identified variants. Logistic regression analysis was performed to calculate the odds ratios (ORs) and 95 % confidence intervals (CIs) of the candidate variants and risk of AVM. Statistical analyses were performed using SPSS version 21.0.

RESULTS

The RNF213 c.10997T>C variant (amino acid mutation p.M3666T, NM_001256071) was observed in two AVM patients after filtration. It was significantly associated with AVM in the Chinese population (ORs, 10.30 and 25.08; 95 %; CIs, 1.38-77.10 and 4.34-144.90 compared with 1000 Genome Project of Chinese Han Population and GeneSky in-house database, respectively).

CONCLUSION

Rare variants of RNF213 are associated with AVM in the Chinese population, suggesting the important role of RNF213 in AVM. Further studies are needed to verify these findings.

Maternal and Fetal Outcomes in Women with Brain Arteriovenous Malformation Rupture during Pregnancy

BACKGROUND

Sporadic brain arteriovenous malformations (BAVM) are a major cause of hemorrhagic stroke in younger persons. Prior studies have reported contradictory results regarding the risk of hemorrhage during pregnancy, and there are no standard guidelines for the management of pregnant women who present with BAVM rupture. The purpose of this study is to describe maternal and fetal outcomes and treatment strategies in patients with BAVM hemorrhage during pregnancy.

METHODS

We performed a retrospective review of the University of California, San Francisco Brain AVM Project database for female patients who were pregnant at the time of BAVM hemorrhage between 2000 and 2017. Clinical and angiographic characteristics at presentation, BAVM treatment, and maternal outcomes using modified Rankin scale (mRS) score at presentation and 2-year follow-up were recorded. Fetal outcomes were abstracted from medical records and maternal reports.

RESULTS

Sixteen patients presented with BAVM hemorrhage during pregnancy, 81% (n = 13) of whom were in their second or third trimester. Three patients (19%) who were in their first trimester terminated or miscarried pregnancy prior to BAVM intervention. Of the remaining 13 patients, 77% (n = 10) received emergent BAVM treatment at time of hemorrhage prior to delivery, and 85% of patients achieved BAVM obliteration and good maternal outcomes (mRS 0-2) at 2-year follow-up. All patients had uncomplicated deliveries (69% cesarean and 23% vaginal) with no reports of postnatal cognitive or developmental delays in infants at 2-year follow-up.

CONCLUSIONS

Our study shows good long-term maternal and fetal outcomes in ruptured BAVM patients presenting during pregnancy, the majority who received BAVM interventional treatment prior to delivery.

Manejo bimodal de aneurismas asociados a malformaciones arteriovenosas cerebrales. Reporte de caso y breve revisión de la literatura

La patogénesis de los aneurismas intracraneales asociados a malformaciones arteriovenosas cerebrales no es bien entendida y es aún objeto de discusión. Las decisiones sobre cuándo y cómo tratar los aneurismas intracraneales de estas características siempre han sido un reto terapéutico tanto para neurocirujanos vasculares como para terapistas endovasculares neurológicos. Reportamos el caso de una paciente de 51 años con aneurismas múltiples asociados a una malformación arteriovenosa, así como su manejo neuroquirúrgico, con un análisis comparativo con lo publicado en la literatura médica y científica en los últimos 10 años.

The pathogenesis of intracranial aneurysms associated with arteriovenous malformations is not well understood and is still under discussion; the decisions about when and how to treat intracranial aneurysms of these characteristics have always been a therapeutic challenge for both, vascular neurosurgeons and endovascular neurological therapists. We report the case of a 51-year-old patient with multiple aneurysms associated with arteriovenous malformation, as well as her neurosurgical management, with a comparative analysis what has been published in the medical and scientific literature in the last 10 years.

Does the Diffuseness of the Nidus Affect the Outcome of Stereotactic Radiosurgery in Patients with Unruptured Cerebral Arteriovenous Malformations?

BACKGROUND

We proposed an algorithm to automate the components within the identification of components within the nidus of cerebral arteriovenous malformations (AVMs) which may be used to analyze the relationship between its diffuseness and treatment outcomes following stereotactic radiosurgery (SRS).

OBJECTIVES

to determine the impact of the diffuseness of the AVM nidus on SRS outcomes.

METHODS

This study conducted regular follow-ups of 209 patients with unruptured AVMs who underwent SRS. The diffuseness of the AVM nidus was estimated by quantifying the proportions of vascular nidal component, brain parenchyma, and cerebrospinal fluid in T2-weighted MRIs. We used Cox regression analysis to characterize the association between nidal diffuseness and treatment outcomes in terms of obliteration rate and radiation-induced change (RICs) rate following SRS.

RESULTS

The median AVM volume was 20.7 cm3. The median duration of imaging follow-up was 51 months after SRS. The overall AVM obliteration rate was 68.4%. RICs were identified in 156 of the 209 patients (74.6%). The median proportions of the nidus of AVM and brain parenchyma components within the prescription isodose range were 30.2 and 52.2%, respectively. Cox regression multivariate analysis revealed that the only factor associated with AVM obliteration rate after SRS was AVM volume. However, a larger AVM volume (>20 mL) and a larger proportion of brain parenchyma (>50%) within the prescription isodose range were both correlated with a higher RIC rate following SRS.

CONCLUSIONS

The diffuseness of the nidus indeed appears to affect the RIC rate following SRS in patients with unruptured AVMs.

Metastasis of Carcinoma to a Cerebral Arteriovenous Malformation

BACKGROUND

Although carcinoma metastasis to primary intracranial neoplasms has occasionally been reported, metastasis to a cerebral arteriovenous malformation (AVM) has been exceedingly rare, with only 5 cases reported to date. In the present study, we have reported a case of lung carcinoma that had metastasized to a cerebral AVM. To the best of our knowledge, the present report is the first case in which the pathological examination detected the bleeding mechanism of this rare condition, showing destruction of the feeders by the metastatic tumor.

CASE DESCRIPTION

A 61-year-old man who had had a tumor shadow in the right middle lung field identified at a medical examination 5 weeks previously had suddenly experienced a disturbance of consciousness. Head computed tomography and computed tomography angiography revealed a right occipital subcortical hemorrhage with abnormal vessels, suggesting a ruptured AVM. Magnetic resonance imaging with gadolinium-based contrast agents did not show any other lesions. Cerebral angiography revealed a Spetzler-Martin grade III AVM in the right occipital lobe. Endovascular feeder embolization and subsequent removal of the AVM were performed. Histopathological examination of the resected mass showed a small cell carcinoma that had metastasized to the AVM. The tumor cells had infiltrated to the vessel walls of the feeders, which might have elicited the bleeding.

CONCLUSION

Although rare, clinicians should recognize that undifferentiated carcinomas can metastasize to AVMs and cause bleeding. Because the preoperative diagnosis can be difficult, even using the latest imaging modalities, careful examination of the resected specimen is required to reveal such pathological conditions.

Multimodal Assessment of Cerebral Autoregulation and Autonomic Function After Pediatric Cerebral Arteriovenous Malformation Rupture

BACKGROUND

Management after cerebral arteriovenous malformation (AVM) rupture aims toward preventing hemorrhagic expansion while maintaining cerebral perfusion to avoid secondary injury. We investigated associations of model-based indices of cerebral autoregulation (CA) and autonomic function (AF) with outcomes after pediatric cerebral AVM rupture.

METHODS

Multimodal neurologic monitoring data from the initial 3 days after cerebral AVM rupture were retrospectively analyzed in children (< 18 years). AF indices included standard deviation of heart rate (HRsd), root-mean-square of successive differences in heart rate (HRrmssd), low-high frequency ratio (LHF), and baroreflex sensitivity (BRS). CA indices include pressure reactivity index (PRx), wavelet pressure reactivity indices (wPRx and wPRx-thr), pulse amplitude index (PAx), and correlation coefficient between intracranial pressure pulse amplitude and cerebral perfusion pressure (RAC). Percent time of cerebral perfusion pressure (CPP) below lower limits of autoregulation (LLA) was also computed for each CA index. Primary outcomes were determined using Pediatric Glasgow Outcome Score Extended-Pediatrics (GOSE-PEDs) at 12 months and acquired epilepsy. Association of biomarkers with outcomes was investigated using linear regression, Wilcoxon signed-rank, or Chi-square.

RESULTS

Fourteen children were analyzed. Lower AF indices were associated with poor outcomes (BRS [p = 0.04], HRsd [p = 0.04], and HRrmssd [p = 0.00]; and acquired epilepsy (LHF [p = 0.027]). Higher CA indices were associated with poor outcomes (PRx [p = 0.00], wPRx [p = 0.00], and wPRx-thr [p = 0.01]), and acquired epilepsy (PRx [p = 0.02] and wPRx [p = 0.00]). Increased time below LLA was associated with poor outcome (percent time below LLA based on PRx [p = 0.00], PAx [p = 0.04], wPRx-thr [p = 0.03], and RAC [p = 0.01]; and acquired epilepsy (PRx [p = 0.00], PAx [p = 0.00], wPRx-thr [p = 0.03], and RAC [p = 0.01]).

CONCLUSIONS

After pediatric cerebral AVM rupture, poor outcomes are associated with AF and CA when applying various neurophysiologic model-based indices. Prospective work is needed to assess these indices of CA and AF in clinical decision support.

N6-methyladenosine methyltransferase METTL3 affects the phenotype of cerebral arteriovenous malformation via modulating Notch signaling pathway

Background

Cerebral arteriovenous malformation (AVM) is a serious life-threatening congenital cerebrovascular disease. Specific anatomical features, such as nidus size, location, and venous drainage, have been validated to affect treatment outcomes. Until recently, molecular biomarkers and corresponding molecular mechanism related to anatomical features and treatment outcomes remain unknown.

Methods

RNA N6-methyladenosine (m⁶A) Methyltransferase METTL3 was identified as a differentially expressed gene in groups with different lesion sizes by analyzing the transcriptome sequencing (RNA-seq) data. Tube formation and wound healing assays were performed to investigate the effect of METTL3 on angiogenesis. In addition, Methylated RNA Immunoprecipitation Sequencing technology (MeRIP-seq) was performed to screen downstream targets of METTL3 in endothelial cells and to fully clarify the specific underlying molecular mechanisms affecting the phenotype of cerebral AVM.

Results

In the current study, we found that the expression level of METTL3 was reduced in the larger pathological tissues of cerebral AVMs. Moreover, knockdown of METTL3 significantly affected angiogenesis of the human endothelial cells. Mechanistically, down-regulation of METTL3 reduced the level of heterodimeric Notch E3 ubiquitin ligase formed by DTX1 and DTX3L, thereby continuously activating the Notch signaling pathway. Ultimately, the up-regulated downstream genes of Notch signaling pathway dramatically affected the angiogenesis of endothelial cells. In addition, we demonstrated that blocking Notch pathway with DAPT could restore the phenotype of METTL3 deficient endothelial cells.

Conclusions

Our findings revealed the mechanism by which m⁶A modification regulated the angiogenesis and might provide potential biomarkers to predict the outcome of treatment, as well as provide suitable pharmacological targets for preventing the formation and progression of cerebral AVM.

Delayed Fragmentation and Distal Embolization of Retained Microcatheter Causing Lower Limb Ischemia: Case Report and Review of the Literature

BACKGROUND

Endovascular microcatheter adherence and retention is an uncommon complication during brain arteriovenous malformation (AVM) embolization with glue or ethylene-vinyl alcohol copolymer that has previously reported, although there are sparse reports of symptomatic complications thereafter.

CASE DESCRIPTION

We present a unique complication 6 years after initial embolization of a cerebral AVM. The patient presented with acute lower limb insufficiency with computed tomography angiogram revealing fragmentation of the microcatheter and associated popliteal aneurysm. The patient underwent an emergency grafting and removal of the retained fragment and recovered without deficit postoperatively.

CONCLUSIONS

Fragmentation over retained microcatheters remains a concern that may be worth monitoring in the long term, although there are no recommendations for timing.

Impact of AVM location on language cortex right-hemisphere reorganization: A voxel-based lesion-symptom mapping study

OBJECTIVES

Cerebral arteriovenous malformations (AVMs) are congenital malformations, and right-sided dominance of the language cortex is not a rare phenomenon for patients with AVM involving language area. We tried to use voxel-based lesion-symptom mapping (VLSM) method to depict the location of AVM nidus and to demonstrate the relationship between AVM location and the pattern of language cortex reorganization.

PATIENTS AND METHODS

The authors retrospectively reviewed clinical and imaging data of 70 adult patients with unruptured cerebral AVMs who underwent blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI) of language task. All patients were right handed, and all lesions were located in the left cerebral hemisphere. Lateralization indexes (LI) of the BOLD signals were calculated for Broca and Wernicke areas separately and were used to reflect the degree of right-sided dominance of the two language areas. VLSM method was applied to study the relationship between AVM location and LI of language task activations.

RESULTS

Statistical analysis revealed that the change of LI of Broca area was significantly associated with lesions located in the inferior frontal gyrus, pre- and post-central gyrus, supramarginal gyrus and middle frontal gyrus. The change of LI of Wernicke area was significantly associated with lesions located in the left superior, middle, inferior and transverse temporal gyrus.

CONCLUSION

These findings provide new evidence that the language cortex reorganization patterns in AVM patients have anatomic specificity.

De novo distal middle cerebral artery aneurysm post-excision of intracerebral arteriovenous malformation in an 8-year old

Cerebral arteriovenous malformations (AVMs) are frequently associated with concurrent aneurysms. These aneurysms are commonly haemodynamically related to the AVM and can be classified into extranidal or intranidal in reference to the AVM nidus. An aneurysm arising from an artery that does not angiographically contribute to the blood flow to the AVM is uncommon. A distal middle cerebral artery (dMCA) aneurysm itself is also a rare presentation, especially in paediatric population. We present a rare case of dMCA aneurysm that was noted after successful surgical management of a ruptured AVM in an 8-year-old child and its management. BACKGROUND: About 10-30% of patients with cerebral arteriovenous malformation (AVM) have an associated artery aneurysm. The majority of these aneurysms are flow-related to the malformation. These aneurysms can be classified into extranidal or intranidal in reference to the AVM nidus Rammos et al Am J Neuroradiol 37:1966-1971, [1]. An aneurysm arising from a different artery that does not angiographically contribute to the blood flow associated with the AVM is less common and would generally be regarded as unrelated to the AVM. Distal cerebral artery aneurysm itself is also a rare presentation, comprising of 1-7% of all middle cerebral artery aneurysm. In children, mycotic infection and dissection are the two most common causes for aneurysm in this location. Unlike in adults, berry aneurysms are uncommon in children. We describe a young patient who was found to have distal middle cerebral artery (dMCA) aneurysm in follow-up DSA (Digital Subtraction Angiogram) after the initial successful surgical treatment for a cerebral frontal AVM. In this particular case, endovascular repair is thought to be the best strategy to treat the aneurysm. However, there still remains a lack of consensus of the best management strategy (surgery or endovascular) in treating flow-related aneurysms in general. This is usually based on an individual case scenario and the treatment is tailored depending on various factors including the expertise of the treating team.

Three-dimensional segmentation and symbolic representation of cerebral vessels on 3DRA images of arteriovenous malformations

BACKGROUND

Endovascular embolization is a minimally invasive interventional method for the treatment of neurovascular pathologies such as aneurysms, arterial stenosis or arteriovenous malformations (AVMs). In this context, neuroradiologists need efficient tools for interventional planning and microcatheter embolization procedures optimization. Thus, the development of helpful methods is necessary to solve this challenging issue.

METHODS

A complete pipeline aiming to assist neuroradiologists in the visualization, interpretation and exploitation of three-dimensional rotational angiographic (3DRA) images for interventions planning in case of AVM is proposed. The developed method consists of two steps. First, an automated 3D region-based segmentation of the cerebral vessels which feed and drain the AVM is performed. From this, a graph-like tree representation of these connected vessels is then built. This symbolic representation provides a vascular network modelization with hierarchical and geometrical features that helps in the understanding of the complex angioarchitecture of the AVM.

RESULTS

The developed workflow achieves the segmentation of the vessels and of the malformation. It improves the 3D visualization of this complex network and highlights its three main components that are the arteries, the veins and the nidus. The symbolic representation then brings a better comprehension of the vessels angioarchitecture. It provides decomposition into topologically related vessels, offering the possibility to reduce the complexity due to the malformed vessels and also determine the optimal paths for AVM embolization during interventions planning.

CONCLUSIONS

A relevant vascular network modelization has been developed that constitutes a breakthrough in the assistance of neuroradiologists for AVM endovascular embolization planning.

Management Options and Outcome of Cerebral Arteriovenous Malformation in Pregnancy: Case Series

Cerebral arteriovenous malformation (AVM) is a rare entity with an estimated prevalence of 0.01-0.05% in the general population. We reviewed hospital obstetric records during 2010-2017 and reported a case series of six patients with cerebral AVM in pregnancy, of which five patients had successful pregnancy, and one maternal mortality.

Transvenous Approach for the Treatment of cerebral Arteriovenous Malformations (TATAM): Study protocol of a randomised controlled trial

BACKGROUND

Transvenous embolisation is a promising technique but the benefits remain uncertain. We hypothesised that transvenous embolisation leads to a higher rate of arteriovenous malformation angiographic occlusion than transarterial embolisation.

METHODS

The Transvenous Approach for the Treatment of cerebral Arteriovenous Malformations (TATAM) is an investigator initiated, multicentre, prospective, phase 2, randomised controlled clinical trial. To test the hypothesis that transvenous embolisation is superior to transarterial embolisation for arteriovenous malformation obliteration, 76 patients with arteriovenous malformations considered curable by up to two sessions of endovascular therapy will be randomly allocated 1:1 to treatment with either transvenous embolisation (with or without transarterial embolisation) (experimental arm) or transarterial embolisation alone (control arm). The primary endpoint of the trial is complete arteriovenous malformation occlusion, assessed by catheter cerebral angiography. Complete occlusions will be confirmed at 3 months, while incompletely occluded arteriovenous malformations, considered treatment failures, will then be eligible for complementary treatments by surgery, radiation therapy, or even transvenous embolisation. Standard procedural safety outcomes will also be assessed. Patient selection will be validated by a case selection committee, and participating centres with limited experience in transvenous embolisation will be proctored.

DISCUSSION

The TATAM trial is a transparent research framework designed to offer a promising but still unvalidated treatment to selected arteriovenous malformation patients. Clinical Trial Registration-URL: http://www.clinicaltrials.gov . Unique identifier: NCT03691870.

Subarachnoid Hemorrhage Due to Flow-Related Dissection of the Posterior-Inferior Cerebellar Artery Associated with a Distal Arteriovenous Malformation

BACKGROUND

Cerebral arteriovenous malformations (CAVMs) are characterized by altered hemodynamics and associated with angioanatomic changes, such as aneurysms. We encountered a patient with a CAVM-associated dissection of the medial trunk of the posterior inferior cerebellar artery (PICA) instead of an aneurysm.

CASE DESCRIPTION

We report the case of a 56-year-old male patient with spontaneous subarachnoid hemorrhage within the cisterna magna and fourth ventricle. Digital subtraction angiography revealed a cerebellar arteriovenous malformation located within the inferior semilunar lobule that did not anatomically match the bleeding pattern. The left PICA, serving as a primary feeding artery, showed a dissection of the proximal portion of the medial trunk with a precise anatomic association with the blood in the telovelotonsillar space. CAVM-induced hyperdynamic flow through the feeding vessel is the most plausible pathophysiologic explanation for the dissection. Complete microsurgical resection of the CAVM was performed, and 3-month follow-up digital subtraction angiography showed complete regression of the dissection, disappearance of irregularities, and significant caliber reduction of the medial PICA trunk.

CONCLUSIONS

This is the first report of a hyperdynamic flow-related dissection of a CAVM-associated feeding vessel. Microsurgical resection of the CAVM allowed for spontaneous resolution of the dissected area by restoration of normal rheodynamics.

[Functional lateralization of major Chinese language cortex for presurgical evaluation in neurosurgery]

Objective: To investigate the functional lateralization of major Chinese language cortex in patients with cerebral arteriovenous malformation (AVM) in dominant hemispheric via functional magnetic resonance imaging (fMRI). Methods: Nine right-handed normal volunteers and fourteen patients with cerebral AVM in dominant hemisphere diagnosed in Beijing Tiantan Hospital between December 2017 and June 2018 were included. Three language tasks (semantic judgment, word reading, and listening comprehension) were applied to activate language areas. Lateralization index (LI) was used to show the dominant hemisphere. Results: In the control group, right-sided lateralization of BOLD signal activations was observed in 0/27 (0%) of the language tasks. While in the AVM patients, right-sided lateralization of BOLD signal activations was observed in 8/42 (19%) language tasks. The difference was statistically significant (χ(2)=5.73, P=0.019). Conclusions: The dominant hemisphere of different language tasks may be different in patients with cerebral lesions. Compared with normal controls, patients with cerebral AVM in dominant hemispheric are more likely to have right-sided lateralization of language cortex.

Usefulness of High-Resolution Three-Dimensional Multifusion Medical Imaging for Preoperative Planning in Patients with Cerebral Arteriovenous Malformation

BACKGROUND

Successful resection of arteriovenous malformation (AVM) depends on preoperative assessment of the detailed morphology of the AVM. Simultaneous detailed three-dimensional visualization of the feeding arteries, draining veins, and surrounding structures is needed. The aim of this study was to evaluate the usefulness of high-resolution three-dimensional multifusion medical imaging (HR-3DMMI) for preoperative planning of AVM resection.

METHODS

HR-3DMMI combined magnetic resonance imaging, magnetic resonance angiography, thin-slice computed tomography, and three-dimensional rotational angiography. Surface rendering was mainly used for creation of HR-3DMMI using multiple thresholds to create three-dimensional models. HR-3DMMI technique was used in 8 patients for preoperative planning, and imaging findings were compared with operative findings.

RESULTS

All feeding arteries and draining veins were found intraoperatively at the same position as estimated preoperatively and were occluded as planned preoperatively.

CONCLUSIONS

HR-3DMMI technique demonstrated the precise locations of feeding arteries, draining veins, and surrounding important tissues, such as corticospinal tract and arcuate fiber, preoperatively and estimated the appropriate route for resection of the AVM. HR-3DMMI is expected to be a very useful support tool for surgery of AVM.

Elevated end-diastolic ratio of the common carotid artery due to cerebral arteriovenous malformation: Two case reports

An elevated end-diastolic (ED) ratio of the common carotid artery (CCA) is an indicator of occlusive lesions of the distal portion of the internal carotid artery. We report 2 cases of cerebral arteriovenous malformation (AVM) showing an elevated ED ratio of the CCA, which decreased after surgery. Case 1 was a 28-year-old man with chronic recurrent headache with aura, and case 2 was a 29-year-old woman with sudden-onset headache and intracerebral hemorrhage without neurologic abnormality. In both cases, digital subtraction angiography revealed a Spetzler-Martin Grade IV AVM, which was mainly fed by branches of the left middle cerebral artery with venous drainage into superficial and deep cerebral veins. Preoperative carotid ultrasonography showed an elevated CCA ED ratio (1.38 in case 1 and 1.47 in case 2; left > right) without atherosclerotic lesions. Patients' AVMs were successfully resected. In both cases, the ED ratio was decreased after surgery (to 1.05 in case 1 and 1.20 in case 2). A decrease in vascular resistance on 1 side caused by cerebral AVM can result in an increase in the CCA ED ratio comparable to that of carotid axis occlusion.

Radiosurgery reduces plasma levels of angiogenic factors in brain arteriovenous malformation patients

PURPOSE

Aberrant expression of angiogenic factors has been anecdotally documented in brain arteriovenous malformation (AVM) nidus vessels; however, no data is available on the effect of radiosurgery on the levels of angiogenic factors in AVM patients. We sought to determine the plasma contents of VEGF, TGF-β, Ang-2 and bFGF in 28 brain AVM patients at baseline and post radiosurgery and further analyzed the relationship between plasma contents of these angiogenic factors with clinicopathologic variables of these patients.

METHODS

We enrolled brain AVM patients who underwent Cyberknife radiosurgery at our hospital between January 2014 and December 2015. Brain AVM was confirmed by cerebral angiography and radiosurgery was performed with Cyberknife irradiation. Plasma contents of VEGF, TGF-β, Ang-2 and bFGF were analyzed using commercially available enzyme-linked immunoassay (ELISA) kits.

RESULTS

The baseline plasma VEGF content was 222.63 pg/mL (range 43.25-431.25 pg/mL). At three months post surgery, there was a significant -34.29% decline in plasma VEGF content versus baseline (P = 0.000). Furthermore, the median baseline plasma VEGF levels were higher in brain AVM with a nidus volume ≥ 10 cm³) than those with a nidus volume < 10 cm³ [median(IQR) 293.5 (186.5,359.25) vs. 202 (59.75, 270.75) pg/mL, P = 0.057]. The baseline plasma TGF-β content was 556.17 pg/mL (range 44.44-1486.11 pg/mL) and there was a significant -27.47% decline in plasma TGF-β content at 3 months post radiosurgery versus baseline (P = 0.015). Moreover, the baseline plasma ANG-2 content was 214.27 pg/mL (range 77.14-453.76 pg/mL). There was an immediate and significant -12.47% decline in plasma ANG-2 content post surgery versus baseline (P = 0.002). At three months post surgery, the plasma ANG-2 content still remained significantly depressed versus baseline (P = 0.002). In addition, the baseline plasma bFGF content was 9.17 pg/mL (range 3.67-36.78 pg/mL). No significant difference in plasma bFGF content was observed immediately post surgery and 3 months post surgery versus baseline (P = 0.05).

CONCLUSIONS

Radiosurgery for brain AVM patients significantly reduced the plasma levels of angiogenic factors. The plasma angiogenic factors may be candidate markers for aberrant agniogenesis of brain AVM and patient response to radiosurgery.

Long-term Outcomes With Planned Multistage Reduced Dose Repeat Stereotactic Radiosurgery for Treatment of Inoperable High-Grade Arteriovenous Malformations: An Observational Retrospective Cohort Study

BACKGROUND

There is no consensus regarding the optimal management of inoperable high-grade arteriovenous malformations (AVMs). This long-term study of 42 patients with high-grade AVMs reports obliteration and adverse event (AE) rates using planned multistage repeat stereotactic radiosurgery (SRS).

OBJECTIVE

To evaluate the efficacy and safety of multistage SRS with treatment of the entire AVM nidus at each treatment session to achieve complete obliteration of high-grade AVMs.

METHODS

Patients with high-grade Spetzler-Martin (S-M) III-V AVMs treated with at least 2 multistage SRS treatments from 1989 to 2013. Clinical outcomes of obliteration rate, minor/major AEs, and treatment characteristics were collected.

RESULTS

Forty-two patients met inclusion criteria (n = 26, S-M III; n = 13, S-M IV; n = 3, S-M V) with a median follow-up was 9.5 yr after first SRS. Median number of SRS treatment stages was 2, and median interval between stages was 3.5 yr. Twenty-two patients underwent pre-SRS embolization. Complete AVM obliteration rate was 38%, and the median time to obliteration was 9.7 yr. On multivariate analysis, higher S-M grade was significantly associated ( P = .04) failure to achieve obliteration. Twenty-seven post-SRS AEs were observed, and the post-SRS intracranial hemorrhage rate was 0.027 events per patient year.

CONCLUSION

Treatment of high-grade AVMs with multistage SRS achieves AVM obliteration in a meaningful proportion of patients with acceptable AE rates. Lower obliteration rates were associated with higher S-M grade and pre-SRS embolization. This approach should be considered with caution, as partial obliteration does not protect from hemorrhage.

Surgical Management of Adverse Radiation Effects After Gamma Knife Radiosurgery for Cerebral Arteriovenous Malformations: A Population-Based Cohort Study

OBJECTIVE

The goal of this study is to report our experience in the surgical treatment of cerebral arteriovenous malformations (cAVMs) related permanent symptomatic adverse radiation effects (PSAREs), to clarify an appropriate surgical management and to identify the risk factors related to their development.

METHODS

We evaluated 549 patients treated with Gamma Knife radiosurgery (GKRS) for cAVMs with a follow-up of at least 8 years. Univariate and multivariate analyses were used to test different risk factors related to the development of PSARE. We retrospectively reviewed the records of these patients to analyze the clinical outcome.

RESULTS

Fourteen patients (2.5%) developed PSARE and were submitted to surgery. Higher average treated volume represents a significant risk factors for the development of PSARE (P < 0.05); on the other hand, older age and higher average dose reduce the risk of PSARE (P < 0.05). A favorable clinical outcome was achieved in 13 patients (93%) after surgery; in 1 patient, the unfavorable outcome was due to hemorrhage that occurred months after GKRS. Serial MRI scans following either surgical removal of the nodule or Ommaya reservoir positioning showed progressive reduction of brain edema in all cases.

CONCLUSIONS

The management of PSARE is controversial, especially for cAVMs treated with SRS. Surgical removal is rarely needed, but-if unavoidable-it can be a valuable option in experienced hands. A careful preoperative planning is always necessary to detect pathologic blood flow through the PSARE.

In vitro characteristics of endothelial cells prepared from human cerebral arteriovenous malformation lesions using a novel method

BACKGROUND AND PURPOSE

The cerebral arteriovenous malformation (cAVM) is a usual and continually unaware reason of heamorrhage and seizure. It contains of feeder arteries, drain veins and abnormal vessel nets. However, pathologic mechanisms of the development of cAVM are unknown. The purpose of this study was to explore a novel protocol to isolate, culture and passage endothelial cells (ECs) from human cAVM lesions.

METHODS

We developed a protocol for isolating and growing ECs from eight patients with cAVM. The tissues were microsurgically removed from cAVM lesion and were digested by 0.25% Trypsin-EDTA, and cultured in ECM medium. ECs were selected by FACS and confirmed their EC origin by immunocytochemistry of the basic expression patterns of CD31 and CD34. LDL-uptake and capillary tube formation were used to determine their functional features.

RESULTS

The isolated cAVM-ECs exhibited contact inhibition of growth and appearance of rounded cobblestone. cAVM-ECs were CD31- and CD34-positive. In functional assays, cAVM-ECs were able to uptake LDL and form capillary tubes. cAVM-ECs from younger patients proliferated faster than that from elders, and cAVM-ECs were less stable than normal artery ECs. In addition, cAVM-ECs appeared to more easily transform into mesenchymal cells than normal artery ECs.

CONCLUSION

Using the protocol, isolated cAVM-ECs are stably established, and retain their endothelial phenotypes. These cAVM-ECs may provide a biological tool to examine molecular phenotypes and mechanisms responsible for human cAVM.

Giant vein of Galen malformation in an adult

Vein of Galen malformations (VoGMs) are rare vascular malformations resulting from persistent shunting of primitive choroidal vessels into the median prosencephalic vein of Markowski. VoGMs are associated with poor clinical outcome with a reported 76.7% mortality if left untreated. We present an exceedingly rare case of a giant, untreated VoGM measuring 7.8 × 5.5 × 7 cm in a 42-year-old man. The embryologic origin, classification, clinical manifestations, and treatment options of VoGMs are discussed with a review of pertinent literature.

Intraoperative Anatomical and Hemodynamic Analysis of Intracerebral Arteriovenous Malformations by Semi-quantitative Color-coded Indocyanine Green Videoangiography

Objective and Background:

To evaluate possible roles for indocyanine green (ICG)-based FLOW 800 software in surgical treatment of cerebral arteriovenous malformations (AVMs).

Methods:

We perform ICG videoangiography several times for each step of AVM resection to elucidate feeders, drainers, and cerebral perfusion.

Results:

Since 2010, 22 AVM surgeries in our department have been conducted using FLOW 800 intraoperatively. We demonstrated ICG angiograms, color-coded images, and semi-quantitative curves for AVMs. By reviewing all these modalities, we would define vascular structure of the AVM, proceed with resection, and finally recheck for any remnant.

Conclusions:

ICG FLOW 800 software helps the surgeon to recognize feeding and draining vessels of an AVM intraoperatively. Further studies to evaluate semi-quantitative acquired data regarding blood flow and tissue perfusion are warranted.

Relationship of pulsatility and resistance indices to cerebral arteriovenous malformation angioarchitectural features and hemorrhage

The role that hemodynamics plays in the pathophysiology of cerebral arteriovenous malformation (AVM) hemorrhage remains unclear. Here, we examine the relationship of pulsatility and resistance indices to AVM angioarchitectural features and hemorrhage. Records of patients with cerebral AVMs evaluated at our institution between 2007-2014 and with flows obtained before treatment using quantitative magnetic resonance angiography (QMRA) were retrospectively reviewed. Flow volume rate and flow velocity were measured in primary arterial feeders and compared to their contralateral counterparts. Pulsatility index (PI)=[(systolic flow velocity-diastolic flow velocity)/mean flow velocity] and resistance index (RI)=[(systolic flow velocity-diastolic flow velocity)/systolic flow velocity] were calculated for each feeder and compared to the normal contralateral vessel. Relationships between PI, RI and AVM clinical and angioarchitectural features were assessed using linear regression. Seventy-two patients with a total of 101 feeder arteries were included. PI and RI were significantly lower in AVM arterial feeders compared to normal vessels, thereby resulting in significantly higher flow volume rates and flow velocities in feeder vessels. There was no significant association of PI and RI with hemorrhagic presentation, exclusive deep venous drainage, venous stenosis, single draining vein, or deep location. In conclusion, PI and RI can be measured using QMRA and are lower in AVM arterial feeders compared to normal vessels. Although we found no significant correlation between PI, RI, and AVM angioarchitectural characteristics thought to be associated with increased hemorrhage risk, future studies with larger sample sizes may better elucidate this relationship.

Spontaneous obliteration highlights the dynamic nature of cerebral arteriovenous malformations: A case report and review of the literature

Background:

Cerebral arteriovenous malformations (AVMs) are dynamic lesions and have been documented to arise de novo, enlarge, regress, obliterate, and even recur. Spontaneous obliteration of AVM is a rare and poorly understood phenomenon.

Case Description:

We present a case of spontaneous obliteration of AVM in a 60-year-old gentleman who presented with intraparenchymal hemorrhage from a ruptured right parieto-occipital AVM. Angiography performed before gamma knife surgery 4 months after his initial presentation demonstrated complete absence of AVM.

Conclusion:

In our center's 20-year experience of treatment of cerebral AVMs (approximately 600 cases), this is the only case that has been aborted due to spontaneous obliteration leading us to infer that the incidence of spontaneous AVM obliteration is <1%. Spontaneous obliteration of AVM is a rare but well-established phenomenon that bears testimony to the dynamics of this vascular disorder.

Vein of Galen arteriovenous malformation mimicking coarctation of the aorta

Arteriovenous malformation of the vein of Galen is a rare congenital intracranial anomaly lacking a capillary bed and subsequent aneurysmal enlargement of the arterial and venous system, warranting careful management due to associated morbidity and mortality. Coarctations of aorta demonstrate similar neonatal echocardiographic signs to the vein of Galen arterial malformation (VGAM). We present a boy at 37 weeks of gestation whose initial ultrasound and echocardiographic investigations showed a dominant right ventricle and isthmal hypoplasia, suggestive of coarctation of aorta. Follow-up ultrasound and echocardiography revealed an arteriovenous malformation involving middle and posterior cerebral artery branches, eliminating coarctation of aorta. VGAM was confirmed by further ultrasound and angiographic investigation, which demonstrated a tangle of cerebral and choroidal arterial branches centrally feeding into an enlarged vein of Galen. The boy's hemodynamic and neurological statuses were confirmed to be stable despite increased venous pressure. Elective embolization at 7 months of age was complicated by a cerebrovascular accident, resulting in right hemiparesis despite no residual cardiac issues. This case demonstrates that rarely, arteriovenous malformations such as the vein of Galen malformations may be the primary cause of patients presenting with coarctation of aorta. The rarity of this condition and its guarded prognosis make our case of special interest to cardiologists and the perinatal care team.

Ephrin B2 and EphB4 selectively mark arterial and venous vessels in cerebral arteriovenous malformation

OBJECTIVES

Ephrin type B receptor 4 (EphB4, Eph receptor) selectively binds ephrin B2 (Eph ligand). EphB4/ephrin B2 is involved in embryonic vessel development, vascular remodelling and pathological vessel formation in adults (including tumour angiogenesis). Binding of vascular endothelial growth factor (VEGF)-A to the endothelial-specific receptor VEGF receptor-2 is the main extracellular signal triggering angiogenic response. Little is known about the role of EphB4/ephrin B2 during angiogenesis and arteriovenous plasticity in cerebral arteriovenous malformation (cAVM). This study investigated EphB4 and ephrin B2 expression in cAVM.

METHODS

Haemorrhagic (H-AVM) and nonhaemorrhagic (NH-AVM) specimens of AVM nidus, obtained after microsurgical cAVM resection, and normal superficial temporal artery (STA) specimens, were analysed retrospectively. VEGF-A, EphB4 and ephrin B2 expression were studied by immunohistochemistry and immunoblotting.

RESULTS

In cAVM (10 H-AVM; 10 NH-AVM), VEGF-A was immunocytochemically localized to endothelial cells; strong endothelial cell staining was found for EphB4 in veins and ephrin B2 in arteries. Normal STA (n = 10) did not express EphB4 or ephrin B2. EphB4 and ephrin B2 expression was greater in H-AVM than in NH-AVM.

CONCLUSIONS

Endothelial cells are more active in H-AVM than NH-AVM. EphB4 and ephrin B2 play important roles in neovascularization and arteriovenous differentiation/plasticity. These data provide new insights into the aetiology of cAVM and lay a foundation for further study. The notch pathway induced by VEGF-A may be a key signalling pathway in this process.

Successful lung transplantation in a case with diffuse pulmonary arteriovenous malformations and hereditary hemorrhagic telangiectasia

Diffuse pulmonary arteriovenous malformations (AVMs) are associated with a poor prognosis and the therapeutic strategy remains controversial. We describe a pediatric patient with diffuse pulmonary AVMs associated with hereditary hemorrhagic telangiectasia (HHT), who presented with two cerebral AVMs in the parietal and occipital lobes as well. Of note, successful bilateral lung transplantation not only improved the hypoxemia but also resulted in size reduction of the cerebral AVMs. Although it is essential to consider involvements other than pulmonary AVMs, especially brain AVMs, to decide the indication, lung transplantation can be a viable therapeutic option for patients with diffuse pulmonary AVMs and HHT.

The "seagull cry" in a patient with a cerebral arteriovenous malformation

INTRODUCTION

The "seagull cry" is an acoustic phenomenon heard during duplex ultrasound. It is caused by harmonic covibrations of a vessel wall in the presence of high-velocity blood flow. It has been reported in a few cases of cerebrovascular disease, such as severe intracranial stenosis, vasospasm or carotid-cavernous fistula.

MATERIAL AND METHODS

A 35-year-old man underwent transcranial color-coded sonography (TCCS) for work-up of a severe new-onset headache.

RESULTS

Doppler spectral analysis of the right intracranial carotid bifurcation revealed multiple pairs of mirror-image parallel strings, and a high-frequency seagull cry was heard. Computed tomography-angiography and magnetic resonance imaging of the brain showed an arteriovenous malformation in the right temporal lobe.

DISCUSSION

The seagull cry is a "musical murmur" with single or multiple frequency that sounds like a musical tone. This is the first report of this phenomenon in a cerebral arteriovenous malformation.