Transarterial embolization in non-cavernous and cavernous sinus dural arteriovenous fistulas: A systematic review and meta-analysis of proportions

BACKGROUND

Transarterial embolization (TAE) is pivotal in managing non-cavernous and cavernous sinus dural arteriovenous fistulas (CSDAVFs).

METHODS

Systematic searches were conducted across ScienceDirect, Medline, and Cochrane databases for longitudinal studies on TAE outcomes in non-CSDAVFs and CSDAVFs. Post-procedural outcomes, including complete, incomplete, and failed AVFs obliteration, and end-study outcomes were analyzed.

RESULTS

Our meta-analysis involved 27 studies with 643 patients and 736 fistulas. Symptoms in both groups included tinnitus (29.74 %), ocular/visual symptoms (29.12 %), hemorrhage (19.42 %), and headache (19.11 %). Feeding arteries mainly originated from the meningeal arteries (49.16 %). In non-CSDAVFs cases, fistula locations were within sinus complexes (69.23 %) and specific dural areas (28.31 %). Complete AVFs obliteration was 81 % (95 %CI: 70 % - 90 %), slightly higher in non-CSDAVFs (82 %, 95 % CI: 69 % - 92 %) than CSDAVFs (79 %, 95 %CI: 58 % - 95 %). Incomplete obliteration occurred in 14 % (95 %CI: 5 % - 39 %), with rates of 11 % (95 %CI: 2 % - 26 %) in non-CSDAVFs and 19 % (95 % CI: 5 % - 39 %) in CSDAVFs. Failed obliteration was rare (1 %, 95 %CI: 0 % - 3 %), with similar rates in both groups. At end-study follow-up, resolution of AVFs was achieved in 97 % of cases (95 %CI: 92 % - 100 %). However, complications occurred in 17 % of cases (95 %CI: 10 % - 25 %), with a higher incidence in CSDAVFs (22 %, 95 %CI: 9 % - 37 %) compared to non-CSDAVFs (13 %, 95 %CI: 6 % - 23 %).

CONCLUSIONS

TAE with embolic agents demonstrates favorable outcomes in non-CSDAVFs and CSDAVFs, with high rates of AVFs obliteration and resolution. Complications, particularly in CSDAVFs, warrant careful consideration in treatment decisions.

LIQUID - Treatment of high-grade dural arteriovenous fistulas with Squid liquid embolic agent: a prospective, observational multicenter study

BACKGROUND

Endovascular embolization is a feasible treatment for cranial dural arteriovenous fistulas (DAVFs). New embolic agents aim to improve the success of DAVF embolization.

OBJECTIVE

To assess the safety, efficacy, and short-term outcome of the treatment of DAVFs using the new liquid embolic agent Squid.

METHODS

The LIQUID study is a prospective, observational multicenter study on the treatment of high-grade (Cognard type ≥3) DAVFs with the embolic agent Squid. The primary outcome measures were safety (ie, morbidity and mortality), as well as the occlusion rate 90 to 180 days after treatment.

RESULTS

In eight centers, 53 patients (mean age 59.8 years, 22.6% female) were treated in 55 treatment sessions. Of the DAVFs, 56.6% were Cognard type III, 41.5% type IV, and 18.9% were ruptured. Squid 18 was used in 83.6% and Squid 12 in 32.7% of the treatments. The overall rate of intraprocedural or postprocedural adverse events (AEs) was 18.2%. Procedure-related AEs resulting in permanent morbidity were observed in 3.6%. One patient (1.8%) died unrelated to the procedure due to pulmonary embolism. The final complete occlusion rate at 90 to 180 days was 93.2%. After a mean follow-up of 5.5 months, the modified Rankin Scale (mRS) score was stable or improved in 93.0%. In one of the patients, worsening of the mRS score was related to the procedure (1.8%).

CONCLUSION

Squid is a safe and effective liquid embolic agent for the treatment of high-grade DAVFs.

Angioarchitectural Analysis of Arteriovenous Shunts in Dural Arteriovenous Fistulas and Its Clinical Implications

BACKGROUND

Detailed understanding of the angioarchitecture of arteriovenous shunts in dural arteriovenous fistulas (DAVFs) is essential when planning endovascular treatment.

OBJECTIVE

To analyze shunt patterns and their clinical implications in transverse-sigmoid sinus and superior sagittal sinus DAVFs.

METHODS

A total of 48 DAVFs treated with endovascular embolization between January 2010 and June 2021 were investigated. The preprocedural and intraprocedural digital subtraction angiograms were examined to characterize the shunt patterns of DAVFs in terms of anatomic relations to the sinuses and cortical veins. Treatment characteristics and outcomes were evaluated.

RESULTS

The shunt patterns were categorized into 4 types: the direct sinus fistula (n = 8/48, 16.7%), compartmental sinus channel (n = 14/48, 29.1%), mural channel (n = 13/48, 27.1%), and bridging vein shunt (n = 13/48, 27.1%). Mural channel lesions revealed direct (n = 4/13, 30.8%) and indirect (n = 6/13, 46.2%) cortical venous connections. Multiple shunt types were seen in 7 patients. Overall, complete or near-complete occlusion was achieved in 43 patients (89.6%) after the final embolization. Patients with mural channels received the most embolization sessions (1.4 sessions per patient). Procedural venous drainage-related complications occurred in patients with multiple shunt types including mural channel shunts (n = 3). All bridging vein shunts were completely occluded during a single transarterial embolization session.

CONCLUSION

The 4 shunt patterns of DAVFs demonstrate distinct characteristics for the fistula, sinus and cortical vein connection. Meticulous analysis of the angioarchitectural characteristics and clinical implications is warranted for safe and effective treatment.

Endovascular versus surgical treatment of cranial dural arteriovenous fistulas: a single-center 8-year experience

BACKGROUND

Cranial dural arteriovenous fistulas (dAVFs) are rare lesions managed mainly with endovascular treatment (EVT) and/or surgery. We hypothesize that there may be subtypes of dAVFs responding better to a specific treatment modality in terms of successful obliteration and cessation of symptoms and/or risks.

METHODS

All dAVFs treated during 2011-2018 at our hospital were analyzed retrospectively. Presenting symptoms, radiological variables, treatment modality, complications, and residual symptoms were related to dAVF type using the original Djindjian classification.

RESULTS

We treated 112 dAVFs in 107 patients (71, 66% males). They presented with hemorrhage (n = 23; 21%), non-hemorrhagic symptoms (n = 75; 70%), or were discovered incidentally (n = 9; 8%). There were 25 (22%) type I, 29 (26%) type II, 26 (23%) type III, and 32 (29%) type IV fistulas. EVT was the primary treatment modality in 72/112 (64%) dAVFs whereas 40/112 (36%) underwent primary surgery with angiographic obliteration rates of 60% and 90%, respectively. Using a secondary treatment modality in 23 dAVFs, we obtained a final obliteration rate of 93%, including all type III/IV and 26/27 (96%) type II dAVFs. Except for headache, residual symptoms were rare and minor. Permanent neurological complications consisted of five cranial nerve deficits.

CONCLUSIONS

We recommend EVT as first treatment modality in types I, II, and in non-hemorrhagic type III/IV dAVFs. We recommend surgery as first treatment choice in acute hemorrhagic dAVFs and as secondary choice in type III/IV dAVFs not successfully occluded by EVT. Combining the two modalities provides obliteration in 9/10 dAVF cases at a low procedural risk.

Results of transvenous embolization of intracranial dural arteriovenous fistula: a consecutive series of 136 patients with 142 fistulas

OBJECTIVE

Intracranial dural arteriovenous fistula (DAVF) is mainly treated with an endovascular approach. Two major treatment advances include transvenous embolization (TVE) with coils in 1989 and, more recently, transarterial embolization with Onyx. The aim of this study was to present a large monocentric series of patients with DAVF treated with TVE. This series reports more than 20 years of experience and describes the evolution of the medical management of these patients, as well as current indications for this treatment at the authors' center.

METHODS

Consecutive patients treated for intracranial DAVFs with TVE from 1995 to 2018 were included. Clinical and imaging data were systematically collected. Univariate and multivariate analyses were performed to identify factors that were significantly associated with adverse clinical course or complications.

RESULTS

In this study of 136 patients with 142 DAVFs treated with TVE, the occlusion rate was 90%. The median length of follow-up was 11 months. The rate of permanent complications was 5.1%, and the procedure-related mortality rate was 1.5%. Procedure-related mortality was associated with extension of thrombosis that was observed early in our experience. The introduction of a postoperative anticoagulation regimen has drastically decreased the occurrence of this complication. Other minor complications included cochleovestibular syndrome after embolization of lateral sinus DAVF and oculomotor nerve damage after embolization of cavernous sinus DAVF.

CONCLUSIONS

TVE allows efficient occlusion of DAVF. It remains a valid option for DAVF located on a sinus that does not participate in normal venous drainage of the brain.

Glue, Onyx, Squid or PHIL? Liquid Embolic Agents for the Embolization of Cerebral Arteriovenous Malformations and Dural Arteriovenous Fistulas

Background

Endovascular embolization is an effective treatment option for cerebral arteriovenous malformations (AVMs) and dural arteriovenous fistulas (DAVFs). A variety of liquid embolic agents have been and are currently used for embolization of AVMs and DAVFs. Knowledge of the special properties of the agent which is used is crucial for an effective and safe embolization procedure.

Material and Methods

This article describes the properties and indications of the liquid embolic agents which are currently available: cyanoacrylates (also called glues), and the copolymers Onyx, Squid and PHIL, as well as their respective subtypes.

Results

Cyanoacrylates were the predominantly used agents in the 1980s and 1990s. They are currently still used in specific situations, for example for the occlusion of macro-shunts, for the pressure cooker technique or in cases in which microcatheters are used that are not compatible with dimethyl-sulfoxide. The first broadly used copolymer-based embolic agent Onyx benefits from a large amount of available experience and data, which demonstrated its safety and efficacy in the treatment of cerebral vascular malformations, while its drawbacks include temporary loss of visibility during longer injections and artifacts in cross-sectional imaging. The more recently introduced agents Squid and PHIL aim to overcome these shortcomings and to improve the success rate of endovascular embolization. Novelties of these newer agents with potential advantages include extra-low viscosity versions, more stable visibility, and a lower degree of imaging artifacts.

Conclusion

All the available liquid embolic agents feature specific potential advantages and disadvantages over each other. The choice of the most appropriate embolic agent must be made based on the specific material characteristics of the agent, related to the specific anatomical characteristics of the target pathology.

Location of embolization affects patency after coil embolization for pulmonary arteriovenous malformations: importance of time-resolved magnetic resonance angiography for diagnosis of patency

OBJECTIVES

This study aimed to assess the diagnostic accuracy of computed tomography (CT) and time-resolved magnetic resonance angiography (TR-MRA) for patency after coil embolization of pulmonary arteriovenous malformations (PAVMs) and identify factors affecting patency.

METHODS

Data from the records of 205 patients with 378 untreated PAVMs were retrospectively analyzed. Differences in proportional reduction of the sac or draining vein on CT between occluded and patent PAVMs were examined, and receiver operating characteristic analysis was performed to assess the accuracy of CT using digital subtraction angiography (DSA) as the definitive diagnostic modality. The accuracy of TR-MRA was also assessed in comparison to DSA. Potential factors affecting patency, including sex, age, number of PAVMs, location of PAVMs, type of PAVM, and location of embolization, were evaluated.

RESULTS

The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of CT were 82%, 81%, 77%, 85%, and 82%, respectively, when the reduction rate threshold was set to 55%, which led to the highest diagnostic accuracy. The sensitivity, specificity, PPV, NPV, and accuracy of TR-MRA were 89%, 95%, 89%, 95%, and 93%, respectively. On both univariable and multivariable analyses, embolization of the distal position to the last normal branch of the pulmonary artery was a factor that significantly affected the prevention of patency.

CONCLUSIONS

TR-MRA appears to be an appropriate method for follow-up examinations due to its high accuracy for the diagnosis of patency after coil embolization of PAVMs. The location of embolization is a factor affecting patency.

KEY POINTS

• Diagnosis of patency after coil embolization for pulmonary arteriovenous malformations (PAVMs) is important because a patent PAVM can lead to neurologic complications. • The diagnostic accuracies of CT with a cutoff value of 55% and TR-MRA were 82% and 93%, respectively. • The positioning of the coils relative to the sac and the last normal branch of the artery was significant for preventing PAVM patency.

Results of 1940 embolizations for dural arteriovenous fistulas: Japanese Registry of Neuroendovascular Therapy (JR-NET3)

OBJECTIVE

Embolization is the most common treatment for dural arteriovenous fistulas (dAVFs). A retrospective, multicenter observational study was conducted in Japan to clarify the nature, frequency, and risk factors for complications of dAVF embolization.

METHODS

Patient data were derived from the Japanese Registry of Neuroendovascular Therapy 3 (JR-NET3). A total of 40,169 procedures were registered in JR-NET3, including 2121 procedures (5.28%) in which dAVFs were treated with embolization. After data extraction, the authors analyzed complication details and risk factors in 1940 procedures performed in 1458 patients with cranial dAVFs treated with successful or attempted embolization.

RESULTS

Transarterial embolization (TAE) alone was performed in 858 cases (44%), and transvenous embolization (TVE) alone was performed in 910 cases (47%). Both TAE and TVE were performed in one session in 172 cases (9%). Complications occurred in 149 cases (7.7%). Thirty-day morbidity and mortality occurred in 55 cases (2.8%) and 16 cases (0.8%), respectively. Non-sinus-type locations, radical embolization as the strategy, procedure done at a hospital that performed dAVF embolization in fewer than 10 cases during the study period, and emergency procedures were independent risk factors for overall complications.

CONCLUSIONS

Complication rates of dAVF embolization in Japan were acceptable. For better results, the risk factors identified in this study should be considered in treatment decisions.

Successfully disposal of an acute MCA occlusion by Onyx during AVM embolism

Purpose: To report a rare complication that Onyx gel blocked the MCA trunk and branches unexpectedly during AVM embolism and our strategy to rescue. Material and methods: A 16 years old otherwise healthy girl hold a left side Spetzler - Martin grade III fronto-temporal AVM, during embolization, the L-MCA and its branches were blocked by Onyx completely, the patient was transferred to the operating room to extract the Onyx gel immediately. Result: After totally 10 arterotomies, all the Onyx gel were removed. 8 hours after occlusion, all arteries were then seen to pulsate. Conclusion: Iatrogenic MCA full-length acute occlusion is a rare and severe complication during AVM embolism. Carefully identify the feeding arteries, micro-catheter angiography before Onyx gel injection and balloon-assisted embolism could probably prevent it. Surgical operation to extract onyx gel and re-canalize MCA was recommended, AVM should be resect if possible.

Coil-Protected Technique for Liquid Embolization in Neurovascular Malformations

OBJECTIVE

To evaluate the safety and efficacy of the coil-protected technique for liquid embolization in neurovascular malformations.

MATERIALS AND METHODS

Twenty-two patients who underwent coil-protected liquid embolization for symptomatic cranial (n = 13) and spinal (n = 9) arteriovenous fistula (AVF) or arteriovenous malformations (AVMs) were identified. A total of 36 target feeder vessels were embolized with N-butyl cyanoacrylate and/or Onyx (Medtronic). This technique was used to promote delivery of a sufficient amount of liquid embolic agent into the target shunt or nidus in cases where tortuous feeding arteries preclude a microcatheter wedging techniqu and/or to prevent reflux of the liquid embolic agent in cases with a short safety margin. The procedure was considered technically successful if the target lesion was sufficiently filled with liquid embolic agent without unintentional reflux. Angiographic and clinical outcomes were retrospectively evaluated.

RESULTS

Technical success was achieved for all 36 target feeders. Post-embolization angiographies revealed complete occlusion in 16 patients and near-complete and partial occlusion in three patients each. There were no treatment-related complications. Of the six patients who showed near-complete or partial occlusion, five received additional treatments: two received stereotactic radiosurgery for cerebral AVM, two underwent surgical removal of cerebral AVM, and one underwent additional embolization by direct puncture for a mandibular AVM. Finally, all patients showed complete (n = 19) or near-complete (n = 3) occlusion of the target AVF or AVM on follow-up angiographies. The presenting neurological symptoms improved completely in 15 patients (68.2%) and partially in seven patients (31.8%).

CONCLUSION

The coil-protected technique is a safe and effective method for liquid embolization, especially in patients with various neurovascular shunts or malformations who could not be successfully treated with conventional techniques.

Intraluminal Arterial Filling Defects Misdiagnosed as Pulmonary Emboli: What Else Could They Be?

Pulmonary artery filling defects can be observed in various pathologic processes other than pulmonary embolism, for example, nonthrombotic pulmonary embolism with biological and nonbiological materials and intrinsic pulmonary artery lesions. They have also been described in rare conditions, such as fibrosing mediastinitis and congenital absence or stenosis of pulmonary artery, and some pulmonary parenchymal and airway malignancies. Misdiagnosis is common owing to the relative rarity of these conditions. Correct diagnosis is based on the appropriate clinical suspicion considering the unique clinical features, laboratory findings, and additional radiologic clues inferring a pathology other than pulmonary embolism.

Toward a Better Understanding of Dural Arteriovenous Fistula Angioarchitecture: Superselective Transvenous Embolization of a Sigmoid Common Arterial Collector

BACKGROUND AND PURPOSE

Our aim was to propose a conceptually new angioarchitectural model of some dural arteriovenous fistulas based on subset analysis of transverse and sigmoid type lesions. The "common collector" notion argues for convergence of multiple smaller caliber arterial vessels on a common arterial collector vessel within the sinus wall. Communication of this single collector (or constellation of terminal collectors) with the sinus proper defines the site of arteriovenous fistula, which can be closed by highly targeted embolization, preserving the sinus and avoiding unnecessary permeation of indirect arterial feeders.

MATERIALS AND METHODS

One hundred consecutive dural arteriovenous shunts were examined. Thirty-six transverse/sigmoid fistulas were identified within this group and analyzed for the presence of a common arterial collector as well as other parameters, including demographics, grade, treatment approach, and outcome.

RESULTS

A common collector was identified in nearly all Cognard type I lesions (15 fistulas with 14 single collector vessels seen) and progressively less frequently in higher grade fistulas. Identification of the common collector requires careful angiographic analysis, including supraselective and intraprocedural angiographies during treatment, and final embolic material morphology.

CONCLUSIONS

Detailed evaluation of imaging studies allows frequent identification of a vascular channel in the sinus wall, which we argue reflects a compound, common arterial channel (rather than a venous collector) with 1 or several discrete fistulous points between this vessel and the sinus proper. Targeted closure of this channel is often feasible, with sinus preservation and avoidance of embolic material penetration into arteries remote from fistula site.

Embolization of a superior sagittal sinus dural arteriovenous fistula under intrasinus balloon protection: A case report

Endovascular embolization has evolved to become the primary therapeutic option for dural arteriovenous fistulas (DAVFs). While guaranteeing complete occlusion of the fistula orifice, the goal of DAVF embolization is also to ensure the patency of normal cerebral venous drainage. This paper describes a case of successful embolization of a complex DAVF in the superior sagittal sinus with a multistaged approach using a combination of transvenous and transarterial tactics. The strategies and techniques are discussed.

Outcome of transarterial treatment of dural arteriovenous fistulas with direct or indirect cortical venous drainage

BACKGROUND AND PURPOSE

Transarterial Onyx embolization is an effective treatment for patients with intracranial dural arteriovenous fistula (DAVF). A study was performed to determine whether the clinical and radiological outcomes after transarterial Onyx treatment were affected by the type of cortical venous drainage (direct vs indirect) of high-grade DAVF.

MATERIALS AND METHODS

Between May 2006 and December 2014, demographic data, clinical presentation, angiographic characteristics, and treatment-related outcomes were collected for 54 patients divided into two groups (intracranial DAVF with direct and indirect cortical venous drainage). Continuous variables were compared with the two-tailed t test and categorical variables with the χ² test. Statistical significance was set at P<0.05.

RESULTS

Fifty-two patients (71% with direct and 29% with indirect cortical venous drainage) underwent Onyx embolization. Immediate complete occlusion after treatment was observed in about 55% of patients without between-group difference. During the long-term follow-up, complete angiographic occlusion was achieved in 83% of patients. Specifically, 15 additional patients (40%) in the direct cortical venous drainage group progressed to complete occlusion, but only one (6%) in the indirect cortical venous drainage group. Overall, the rate of complete occlusion was higher in patients with DAVF with direct cortical venous drainage (92%) than in those with DAVF with indirect cortical venous drainage (62.5%) (P=0.01). The rate of permanent treatment-related complications was 4%, mostly related to ischemic events. Overall, 80.5% of patients had a good neurological outcome (modified Rankin Scale score 0-2).

CONCLUSIONS

Transarterial Onyx embolization of intracranial high-grade DAVF is safe and effective, particularly for lesions with direct cortical venous drainage.

Safety of Onyx Transarterial Embolization of Skull Base Dural Arteriovenous Fistulas from Meningeal Branches of the External Carotids also Fed by Meningeal Branches of Internal Carotid or Vertebral Arteries

PURPOSE

To analyze the angiographic and clinical results of transarterial embolization with Onyx (Medtronic-Covidien, Irvine, CA) in dural arteriovenous fistulas (DAVFs) partially fed by arteries arising from the carotid siphon or the vertebral arteries.

METHODS

We isolated 40 DAVFs supplied by either the tentorial artery of the internal carotid artery (ICA) or the posterior meningeal artery of the vertebral artery. These DAVFs were embolized with Onyx through the middle meningeal artery or the occipital artery. We reviewed the occurrence of reflux into the arteries of carotid or vertebral origin.

RESULTS

In all the cases, reflux occurred into the first millimeters of the DAVF arterial feeders arising from carotid or vertebral arteries but slowly enough to be controlled by interruption of Onyx injection. Reflux was always minimal and Onyx never reached the ostium of the arteries. No cerebral ischemic complications occurred in our series.

CONCLUSION

The behavior of Onyx is clearly different from that of cyanoacrylate glue, resulting in superior control during injection. Reflux into arteries arising from the ICA or vertebral artery during DAVF treatment always carries a risk of unintentional non-target embolization of normal cerebral vasculature but Onyx appears to be safe in this situation.

Transarterial venous sinus occlusion of dural arteriovenous fistulas using ONYX

PURPOSE

The purpose of this article is to present a case series of transarterial venous sinus occlusion for dural arteriovenous fistulas (DAVFs) of the transverse and sigmoid sinuses.

MATERIALS AND METHODS

From 2006 to 2012, 11 patients with DAVF of the transverse and sigmoid sinuses were treated with transarterial closure of the affected venous sinus using ethylene vinyl alcohol copolymer (ONYX). The consecutive retrospective cohort included six female and five male patients with an age range of 30-79. Patients presented with stroke, intracranial hemorrhage, seizure, headache, focal neurologic deficit or cognitive change. Lesions were categorized as Cognard II a + b (n = 5) or Cognard II b (n = 6). Four of this latter group consisted of isolated sinus segments. Selection criteria for dural sinus occlusion included direct multi-hole fistulas involving a broad surface in length or circumference of the sinus wall. External carotid artery (ECA) branches were directly embolized when considered safe. High-risk arterial supply from ICA, PICA, AICA or ECA cranial nerve branches were closed via retrograde approach during sinus occlusion.

RESULTS

DAVF closure was accomplished in all 11 patients with a total of 17 embolization procedures using ONYX. High-risk arterial collaterals were closed via artery-artery or artery-sinus-artery embolization. The vein of Labbe was spared in the four cases with initial antegrade flow. No neurologic complications occurred, and DAVF closures were durable on three-month angiography.

CONCLUSION

Transarterial closure of the transverse and sigmoid sinuses.

Onyx Embolization for Tentorial Dural Arteriovenous Fistula with Pial Arterial Supply: Case Series and Analysis of Complications

OBJECTIVE

We describe treatment with Onyx embolization in a series of cases of tentorial dural arteriovenous fistula (DAVF) with pial arterial supply. The aim of this study was to analyze the cause of intraoperative hemorrhage and to explore therapeutic strategies.

METHODS

Retrospective review was performed of 53 consecutive patients with DAVF treated by Onyx embolization between February 2009 and December 2014. Tentorial DAVF with pial arterial supply was diagnosed in 6 patients (2 women and 4 men; mean age, 47.3 years ± 10.2), and transarterial Onyx embolization was performed in these patients. Fisher exact test was used to analyze differences of incidence of procedure-related complications.

RESULTS

Intraoperative hemorrhage occurred in 2 of 6 patients with pial arterial supply. One patient died as a result of hemorrhage, and the other patient survived after craniotomy. The incidence of complications for these 6 patients (2 of 6; 33.3%) was significantly higher (P = 0.0309) compared with patients with DAVF without pial arterial supply (1 of 47; 2.1%).

CONCLUSIONS

Pial arterial supply may be a risk factor for intraoperative hemorrhage during transarterial embolization of DAVF through dural feeders. Identification of pial feeders and early superselective occlusion of such feeders are important for safe management.

Dural Arteriovenous Fistulae: Imaging and Management

Intracranial dural arteriovenous fistulae (DAVF) are pathologic arteriovenous shunts between meningeal arteries and dural venous sinuses or veins. They account for approximately 10% to 15% of all intracranial vascular malformations and are most common in middle-aged patients. DAVF are the most common vascular cause of pulsatile tinnitus. Digital subtraction angiography remains the gold standard for diagnosing these lesions. The pattern of venous drainage determines the type of DAVF and their risk for hemorrhage. Endovascular treatment has become a first-line option for their management. This article describes the natural history, clinical presentation, classification, imaging features, and management options of intracranial DAVF.

Diagnosis and management of intracranial dural arteriovenous fistulas

Dural arteriovenous fistula (DAVF) is a rare type of acquired intracranial vascular malformation. Recent progress in neuroimaging technology, such as advanced MRI and CT, provides non-invasive methods to accurately diagnose DAVF, including evaluation of the hemodynamics of the drainage veins. The clinical manifestations of DAVFs vary widely and depend on the location and venous drainage pattern of arteriovenous shunting. Patients with high grade DAVFs having cortical venous reflux should receive aggressive treatment to prevent the occurrence of intracranial hemorrhage and other neurological deficits related to venous congestion. Intra-arterial or intravenous endovascular embolization remains the primary therapy for high grade DAVF, while open surgery and stereotactic radiosurgery can serve as alternative treatment options. Early and accurate diagnosis with appropriate treatment is the goal for clinical management of DAVFs to reduce symptoms and prevent the development of venous congestion and stroke.

Onyx versus nBCA and coils in the treatment of intracranial dural arteriovenous fistulas

BACKGROUND AND PURPOSE

Intracranial dural arteriovenous fistulas (DAVFs) with cortical venous drainage have significant morbidity and mortality. Complete closure of these lesions is necessary to reduce these risks. The purpose of our study was to compare the outcome of DAVFs treated with Onyx versus those treated with n-Butyl Cyanoacrylate (nBCA) and coil embolization in a case-control study. Compared with nBCA and coil embolization, we hypothesized that Onyx embolization for DAVF is safer and has a higher chance of complete obliteration, with no need for post-embolization surgery for the DAVF.

MATERIALS AND METHODS

From 1998 to 2015, 29 patients who had DAVFs were treated with endovascular embolization. Of these, 24 patients had imaging available for analysis. Successful closure rates, complications, and procedure time were compared between the embolization techniques.

RESULTS

The chance of not requiring post-embolization surgery with Onyx (81.8%) was significantly higher (p = 0.005) than with nBCA (22.22%). The complication rate with Onyx (9.1%) tended to be lower compared with that of nBCA (22.22%; p = 0.37). Procedural time was not significantly different between Onyx (mean 267 minutes) and nBCA (mean 288 minutes) (p = 0.59). The odds ratio of a DAVF being treated with Onyx and then requiring no follow-up surgery was 17.5 (95% CI 1.97-155.4).

CONCLUSION

Our case-control study suggests that Onyx embolization is superior to nBCA and coil embolization in completely obliterating DAVFs, with higher odds of no post-embolization surgery. We also found that Onyx is safe for embolization of DAVFs, with no associated neurological mortality and morbidity.

Efficacy and limitations of transarterial acrylic glue embolization for intracranial dural arteriovenous fistulas

The efficacy and limitations of transarterial acrylic glue embolization for the treatment of intracranial dural arteriovenous fistulas (DAVFs) were investigated. Thirty-four DAVFs treated by transarterial embolization using n-butyl cyanoacrylate were retrospectively reviewed. The locations of DAVFs were the transverse-sigmoid sinus in 11, tentorium in 10, cranial vault in 9, and superior sagittal sinus, jugular bulb, foramen magnum, and middle cranial fossa in 1 each. Borden classification was type I in 7, type II in 3, and type III in 24. Eight patients had undergone prior transvenous coil embolization. Complete obliteration rate was 56% immediately after embolization, 71% at follow-up angiography, and 85% after additional treatments (1 transvenous embolization and 4 direct surgery). Complications occurred in three patients, consisting of asymptomatic vessel perforations during cannulation in two patients and leakage of contrast medium resulting in medullary infarction in one patient. Transarterial glue embolization is highly effective for Borden type III DAVF with direct cortical venous drainage, but has limitations for Borden type I and II DAVFs in which the affected sinus is part of the normal venous circulation. Onyx is a new liquid embolic material and is becoming the treatment of choice for DAVF. The benefits of glue embolization compared to Onyx embolization are high thrombogenicity, and relatively low risks of cranial nerve palsies and of excessive migration into the draining veins of high flow fistula. Transarterial glue embolization continues to be useful for selected patients, and complete cure can be expected in most patients with fewer complications if combined with transvenous embolization or direct surgery.

Prognosis and Treatment of Intracranial Dural Arteriovenous Fistulae: A Systematic Review and Meta-Analysis

Background

Dural arteriovenous fistulae can cause intracranial hemorrhage, but influences on this are unclear.

Summary of review

We searched Ovid MEDLINE (from 1966), Embase (from 1980), and the Cochrane Library in September 2013 for studies of ≥50 adults with dural arteriovenous fistulae describing death or intracranial hemorrhage. Of 16 studies of retrospective associations between dural arteriovenous fistulae vascular anatomy and prior mode of presentation, fistula location in the cavernous sinus was consistently associated with nonhemorrhagic modes of presentation; in five studies involving 855 patients, fistulae with retrograde leptomeningeal (cortical) venous drainage were associated with prior presentation with intracranial hemorrhage (pooled odds ratio 23·2, 95% CI 13·8 to 39·0; *** I2 = 0%). Future intracranial hemorrhage during untreated clinical course was statistically significantly associated with the presence of venous varix in one study and with presentation with intracranial hemorrhage in patients with retrograde leptomeningeal venous drainage in another. In 19 observational studies of treatment of dural arteriovenous fistulae involving 2329 patients, the pooled risk of death was 1·2% (95% CI 0·6 to 1·8, I2 = 35%), that of nonfatal intracranial haemorrhage was 0·5% (95%CI 0·2 to 0·8, I2 = 9%), and that of nonfatal cerebral infarction was 0·7% (95% CI 0·3 to 1·4, I2 = 52%), for a combined risk of 2·5% (95% CI 1·4 to 3·9, I2 = 69%).

Conclusions

Retrograde leptomeningeal venous drainage seems strongly associated with intracranial hemorrhage at presentation of dural arteriovenous fistula, but its association with subsequent intracranial hemorrhage is less clear. Short-term complications of dural arteriovenous fistula treatment affect 2–3% of patients in published reports.

Two microcatheter technique for embolization of arteriovenous fistula with liquid embolic agent

Problem with embolization of arteriovenous fistula (AVF) with liquid embolic agent is its over-penetration into the veins or regurgitation to the proximal feeder without reaching the shunt point. We present a technique that controls the flow of AVF during embolization. Two microcatheter technique consists of positioning one microcatheter close to the AVF for embolization, and with another microcatheter at the proximal feeding artery to control the AVF flow by coiling. Selective angiograms obtained using a distally positioned microcatheter before and after coiling, were compared how much stagnant effect was achieved. Using two microcatheter technique, AVF occlusion was achieved with good penetration of glue to the venous side of the AVF. Its advantage is the ability to push glue into the shunt without causing over-penetration of glue or its reflux along the feeder. Two microcatheter technique was safe and effective in glue embolization of AVF and also expected to be applied with other liquid embolic agent like Onyx.

Balloon-assisted superselective microcatheterization for transarterial treatment of cranial dural arteriovenous fistulas: technique and results

BACKGROUND

In transarterial embolization of anterior cranial fossa and tentorial dural arteriovenous fistula (DAVF), acute angulation of the feeding artery off the internal carotid artery (ICA) may render stable distal catheterization and, therefore, successful transarterial treatment difficult. In some anatomic dispositions, following selection of the feeding artery, subsequent forward force may lead to prolapse of the microcatheter into the ICA rather than advancing it into either the ophthalmic artery or the meningohypophyseal trunk.

OBJECTIVE

We describe a technique that facilitates stable positioning of the microcatheter by using a nondetachable balloon to temporally block the ICA distal to the feeding artery to redirect the catheter into the feeder and to prevent the microcatheter from protruding into the parent artery.

METHODS

In 8 cases where routine superselective microcatheterization failed, a balloon was used to block the ICA distal to the feeding artery in an attempt to facilitate superselective microcatheterization. The balloon was inflated following selection of the feeding vessel with the microcatheter and was kept inflated while advancing the catheter.

RESULTS

: Distal stable microcatheter positions could be obtained in all cases, which enabled us to treat the respective DAVFs with a liquid embolic agent. All 8 cases were angiographically cured with penetration of the liquid embolic agent from the distal artery to the proximal vein, and no procedure-related complications occurred.

CONCLUSION

The described technique may be a helpful adjunct to gain stable distal microcatheter positions during the transarterial treatment of DAVF.

Angioarchitecture of transverse-sigmoid sinus dural arteriovenous fistulas: evaluation of shunted pouches by multiplanar reformatted images of rotational angiography

BACKGROUND AND PURPOSE

Recognition of shunted pouches dural arteriovenous fistula allows us to treat the disease effectively by selective embolization of the pouches at first. However, the shunted pouches in transverse-sigmoid sinus dural arteriovenous fistulas have not been well-documented. Our aim was to evaluate the angioarchitecture of transverse-sigmoid sinus dural arteriovenous fistulas, including the frequency and location of shunted pouches and their feeding arteries. MATERIALS AND METHODS Twenty-five consecutive cases of TSS-DAVFs that underwent rotational angiography and transvenous embolization between 2008 and 2011 were reviewed. Multiplanar reformatted images of rotational angiography and selective angiography were reviewed with a particular focus on the shunted pouches.

RESULTS

All 25 cases showed SPs, with numbers ranging from 1 to 4 pouches (mean, 2.35). The SPs were located at the transverse-sigmoid junction in 16, close to the vein of Labbé in 9, at the dorsal-to-sigmoid sinus in 9, inferior to the sigmoid sinus in 6, at the sigmoid-jugular junction in 5, and inferior to the transverse sinus or the sinus confluence in 14. The SP at the sigmoid sinus was frequently fed by the jugular branch of the ascending pharyngeal artery and the stylomastoid artery. The SP at the transverse-sigmoid junction and the vein of Labbé was fed by the petrosal/petrosquamous and posterior branches of the middle meningeal artery and the transosseous branches of the occipital artery. The SP inferior to the transverse sinus and the sinus confluence was fed by the transosseous branches of the occipital artery and the posterior meningeal artery. All cases were successfully treated by transvenous embolization with sinus packing (n = 13) or selective embolization of the SP (n = 12).

CONCLUSIONS

The presence of SP is a common angioarchitecture of TSS-DAVFs. Identification of the SPs would be useful for their treatment.

Characteristics and long-term outcome of 251 patients with dural arteriovenous fistulas in a defined population

OBJECT

Management of dural arteriovenous fistulas (DAVFs) has changed during the last decades due to increased knowledge of their pathophysiology and natural history as well as advances in treatment modalities. The authors describe the characteristics and long-term outcome of a large consecutive series of patients with DAVFs.

METHODS

Altogether 251 patients with 261 DAVFs were treated in 2 of the 5 neurosurgery departments at Helsinki and Kuopio University Hospitals between 1944 and 2006. Clinical data and radiological examinations were reviewed to assess patients' overall long-term clinical outcome.

RESULTS

The detection rate of DAVFs increased markedly in the 1970s and again in the 1990s when digital subtraction angiography was introduced. The incidence of DAVFs in a defined southern Finnish population was 0.51 per 100,000 individuals per year, which represents 32% of all the brain arteriovenous malformations. In the early part of the series, DAVFs were treated by proximal ligation of the feeding arteries. Later, most of the patients underwent preoperative embolization and subsequent craniotomy, and since 2000 stereotactic radiosurgery has been increasingly used in the treatment of DAVFs. Fifty-nine percent of the 261 fistulas were totally occluded. Treatment-related major complications were seen in 21 patients.

CONCLUSIONS

The advances in diagnostic methods (digital subtraction angiography, CT, and MRI) increased the detection rate of DAVFs, and as treatment modalities developed, the results of treatment and outcome of patients markedly improved with the introduction of endovascular techniques and stereotactic radiosurgery. Microsurgery is of limited use in DAVFs resistant to other treatment modalities.

Rapid and progressive venous thrombosis after occlusion of high-flow arteriovenous fistula

BACKGROUND

Cerebral venous thrombosis developing after surgical or endovascular obliteration of arteriovenous fistula (AVF) is a rare but devastating complication that has not been adequately reported.

CASE DESCRIPTION

Two patients presenting with AVF (1 pial, 1 dural) and large venous pouches were successfully treated by surgical and endovascular means and were neurologically intact postoperatively. Rapid neurologic deterioration was seen on postoperative day 5 in the first patient and postoperative day 2 in the second patient. Both patients had massive cerebral venous thromboses on brain imaging and surgical exploration. One patient died and the other was severely disabled.

CONCLUSION

Rapid occlusion of a high-flow AVF resulting in significant venous stasis can precipitate thrombosis of the venous system distal to the fistulous point. In the presence of large venous pouches and significant venous stasis, strict therapeutic anticoagulation may be required to prevent cerebral venous thrombosis. Therapeutic anticoagulation, though feasible following endovascular treatment, may prove particularly challenging after open surgical interventions given the risk of hemorrhagic complications.

ONYX versus n-BCA for embolization of cranial dural arteriovenous fistulas

PURPOSE

To evaluate the efficacy of n-butyl-2-cyanoacrylate (Trufill n-BCA) versus ethylene vinyl alcohol copolymer (ONYX) for the embolization of cranial dural arteriovenous fistulas (DAVF).

METHODS

Fifty-three consecutive patients with cranial dural AVF were treated with liquid embolic agents from November, 2003 to November, 2008. These 53 patients had 56 lesions treated with arterial embolization. Patients embolized to completion underwent follow-up angiography at 3 months to assess for durable occlusion.

RESULTS

Twenty-one lesions were treated with n-BCA. Seven patients treated with n-BCA had initial angiographic occlusion of their DAVF, which were durable at 3 months. Six patients had adjunctive treatment with coils and/or polyvinyl alcohol particles, but none of these were occluded by endovascular treatment alone. Eleven patients underwent post-embolization surgery for closure of their DAVF. There was one death related to intractable status epilepticus at presentation. One patient developed a major stroke from venous sinus thrombosis after embolization. Thirty-five lesions were treated with ONYX in 34 patients. Twenty-nine patients treated with ONYX had initial angiographic occlusion of their DAVF by embolization alone. One patient had recurrence at 3 months and was re-treated out of 27 total follow-ups. Four patients underwent post-embolization surgical obliteration of their lesions. No deaths or major strokes occurred in this cohort.

CONCLUSION

Initial angiographic occlusion (p=0.0004) and durable angiographic occlusion (p=0.0018) rates for embolization of cranial DAVF show a statistically significant higher efficacy with ONYX compared with n-BCA. Patients embolized with ONYX underwent surgery less frequently compared with those treated with n-BCA (p=0.0015).

Endovascular treatment of tentorial dural arteriovenous fistulae

Tentorial dural arteriovenous fistula (DAVF) is a rare vascular disease, which accounts for less than 4% of all cases of intracranial DAVF. Because of the high risk of intracranial hemorrhage, patients with tentorial DAVF need aggressive treatment. Management approaches are still controversial, and endovascular treatment has emerged as an effective alternative. In the current work, we describe our experience with the endovascular approach in the treatment of these deep and complex DAVF of the tentorium. Eight patients were treated between January 2006 and July 2009. Six patients (75%) presented with intracranial hemorrhage related to the DAVF rupture. Four patients (50%) had subarachnoid bleeding and two had intraparenchymal hematoma. Endovascular treatment was performed via the transarterial route alone in five cases (62.5%), by the transvenous approach in two cases (25.0%) and in a combined procedure using both arterial and venous routes in one patient (12.5%). Complete obliteration of the fistula was achieved in all cases. The outcome at 15 months was favorable (modified Rankin scale 0-3) in seven (87.5%) patients. Complete cure of the lesion was confirmed in these cases. This paper reports on the effectiveness of endovascular treatment in tentorial DAVF management. The choice of the venous versus the arterial approach is determined by regarding different anatomical dispositions.