Onyx Embolization Research Articles

Onyx versus coil embolization for the treatment of type II endoleaks

ObjectiveLittle evidence is available supporting the optimal treatment of type II endoleaks associated with aortic sac growth. Previous studies have lacked comparisons between treatment methods and long-term follow-up. The purpose of the present study was to review our center's experience with the treatment of type II endoleaks comparing Onyx (a liquid embolization agent consisting of ethylene vinyl alcohol; Medtronic, Minneapolis, Minn) embolization and coil embolization. MethodsA retrospective review of prospectively collected data from a vascular surgery database was performed to identify all patients who had undergone embolization of a type II endoleak for aortic sac growth after endovascular aneurysm repair from 2005 to 2018. The Onyx and coil embolization groups were compared using univariate statistics. ResultsA total of 58 patients had undergone 77 embolization procedures for type II endoleaks with either Onyx (27 patients; 37 procedures) or coils (31 patients; 40 procedures). The average aneurysm size at embolization was larger in the Onyx group (77.9 ± 15.1 mm) compared with coil embolization (73.4 ± 11.9 mm). The mean follow-up was 57 months for the Onyx group and 74 months for the coil embolization group. Of the 27 patients who had undergone Onyx embolization, 2 (7.4%) had required graft explantation compared with 5 of the 31 patients (16.1%) who had undergone coil embolization (P = .33). The results of the per-patient analysis showed that the coil embolization group had a significantly greater rate of the need for further reintervention compared with the Onyx group (55% vs 19%; P < .01). Clinical success was observed in 13 patients (48%) in the Onyx embolization group compared with 10 patients (32%) in the coil embolization group (P = .04). Two patients in each group had presented with secondary rupture of the aneurysm sac after attempted embolization. ConclusionsType II endoleaks associated with sac growth treated with Onyx were less likely to require further reinterventions than were those treated with coil embolization. A trend was found toward a greater need for endovascular aneurysm repair explant after coil embolization. With a high rate of further reintervention and potential for sac rupture, diligent follow-up is required after attempted type II embolization, regardless of the technique used.

Endovascular Management of Hepatic Artery Pseudoaneurysm

Hepatic artery pseudoaneurysms (HAP) is a result of injury to the hepatic artery and must be treated due to its high risk of rupture. Endovascular treatment of pseudoaneurysm is effective and minimally invasive. We describe four cases of HAPs that presented with gastrointestinal (GI) bleed. The HAPs developed as a consequence of surgery for carcinoma, infection, trauma due to motor-vehicle accident and biliary instrumentation. Diagnoses were made using CT and conventional angiography. Embolisations were done either to the pseudoaneurysm or the parent artery using glue, Onyx or coils via microcatheter systems. Postembolisation runs showed no opacification of the pseudoaneurysms and the GI bleed resolved with no recurrence. The final outcome differs according to each patient’s underlying illness. We highlight our experience in the endovascular management of HAP using various embolic agents and in particular, Onyx. To the best of our knowledge, this is the first reported case of Onyx embolization of HAP.

Neuro-Endovascular Intervention in Traumatic Carotico-Cavernous Fistulae: A Single-Center Experience.

IntroductionThe aim of this research was to describe a single-center practical experience in the management of traumatic carotid cavernous fistula (CCF).MethodsThere were a total of 31 patients between January 2005 and December 2019 with post-traumatic carotid cavernous sinus fistula (tCCF) who underwent treatment. We classified them into 2 types according to the flow of the CCF: patients with high flow CCF and patients with low flow CCF.ResultsAngiography revealed the high flow types on 21 patients (67.7%), the mean of patients ages are 31.5 years. Onyx embolization was performed in 1 patient (4.76%), transarterial balloon embolization was carried out in 10 patients (47.61%), transarterial coiling in 3 (14.28%) patients while 5 (28.8%) patients underwent transvenous routes to insert the coil and 2 patients (9.52%) were treated conservatively. Complete occlusion was achieved on all patients with coiling whereas the other treatment experiences the reducing flow of the fistula. We obtained 10 patients (32.2%) with a mean of 40.3 years as low flow type CCF. The patients with the low flow type mostly treated conservatively, because their symptoms were acceptable and intermittent.ConclusionThe ballooning currently became the more affordable treatment in our center. Balloon embolization was recommended for medium- and large-size fistula. The coils should be recommended for small-size fistula. In some cases occlusion of the fistula cannot be obtained using the detachable balloon, a coil can be used to occlude the cavernous sinus via trans arterial or trans venous access. If the fistula failed to be treated in traditional ways using balloons or coils, occlusion of the parent vessels could be another option.

INCIDENTAL FINDING OF ONYX EMBOLIZATION OF THE PULMONARY ARTERY: A RARE COMPLICATION OF HIGH FLOW DURAL ARTERIOVENOUS FISTULA REPAIR

SESSION TITLE: Medical Student/Resident Imaging Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Onyx® is a non-adhesive liquid embolic agent used for embolization of brain arteriovenous malformations (bAVMs). We present a case of a 58 year-old woman with shortness of breath found to have a foreign body on chest imaging later determined to be a pulmonary artery Onyx embolus. CASE PRESENTATION: A 58 year-old woman with history of tracheostomy-dependent chronic respiratory failure and dural arteriovenous fistula (DAVF) status post multistage embolic repair presented to the emergency department with shortness of breath, chest tightness, and productive cough for one week. On arrival, she was hypoxic requiring 4L oxygen via tracheostomy mask to maintain an oxygen saturation of 94%. Her exam was remarkable for expiratory wheezes in all lung fields and purulent secretions from her tracheostomy. Chest radiograph revealed a linear radiopaque foreign body overlying the expected location of the right pulmonary artery. A computed tomography of the chest confirmed the finding of a tortuous metallic foreign body within the lower lobe branches of the right pulmonary artery. No lung parenchymal changes were noted in the area supplied by these vessels. Interventional radiology reviewed these images and determined the foreign body to be an irretrievable embolus of the agent used during her DAVF repair, her final treatment having occurred three months prior. This finding was of no significance to the patient’s presentation. She was diagnosed with viral tracheitis and managed symptomatically with complete resolution of symptoms. DISCUSSION: The Onyx liquid embolic agent is made of ethylene vinyl alcohol copolymer dissolved in dimethyl sulfoxide and suspended micronized tantalum powder to make it radio-opaque. It is designed to harden within five minutes of deployment and available in two different formulations varying in viscosity. The lower viscosity Onyx 18 will travel further from the deployment catheter compared to the higher viscosity Onyx 34. Its non-adhesive nature and ease of use makes it a preferable choice to the cyanoacrylate-based (“glue”) agents for some neurointerventionalists. Common complications include hemorrhage, stroke and vessel perforation. Embolus migration has been rarely reported. It is usually noted incidentally on follow-up imaging, as happened with our patient. Clinical presentations are typically asymptomatic, though there have been reports of acute presentations of hypoxemia and superior vena cava syndrome. Treatment options include conservative measures, retrieval of embolus or medical management of symptoms. CONCLUSIONS: Brain AVMs are increasingly being treated with Onyx embolization. Distal migration to non-targeted vessels can be a complication of this procedure, which may be discovered as a puzzling incidental or less commonly an acute finding. Reference #1: FDA, Access Data - Onyx Liquid Embolic system, Instructions for Use, 2003, Site: https://www.accessdata.fda.gov/cdrh_docs/pdf3/P030004c.pdf Reference #2: Tolly, B. T., Kosky, J. L., Koht, A., & Hemmer, L. B. (2016, August 31). A Case Report of Onyx Pulmonary Arterial Embolism... : A&A Practice. LWW. https://journals.lww.com/aacr/fulltext/2017/02150/A_Case_Report_of_Onyx_Pulmonary_Arterial_Embolism.7.aspx#JCL-P-13 Reference #3: Crusio, R., Ramachandran, K., Ramachandran, K., Kupfer, Y., & Tessler, S. (2011). Superior vena cava syndrome caused by embolisation of liquid Onyx. BMJ case reports, 2011, bcr1120103502. https://doi.org/10.1136/bcr.11.2010.3502 DISCLOSURES: No relevant relationships by Timothy Miett, source=Web Response No relevant relationships by Nishka Shetty, source=Web Response

Long-term follow-up of transarterial balloon-assisted Onyx embolization for endovascular treatment of dural arteriovenous fistulas: A single-institution case series and literature review

ObjectiveDural arteriovenous fistulas (DAVFs)—specifically, symptomatic DAVFs with cortical venous reflux—are aggressive lesions with a poor prognosis. Intra-arterial endovascular closure is considered the optional treatment for DAVFs and is currently performed at several international centers. However, long-term outcomes remain unknown. This study investigated the long-term efficacy and safety of transarterial balloon-assisted Onyx embolization in the treatment of DAVFs. MethodsA total of 14 consecutive patients who underwent endovascular treatment for DAVFs were treated by balloon-assisted Onyx embolization. Additionally, we retrospectively reviewed all cases reported in the literature and compared the outcomes of patients treated with single- vs dual-lumen microcatheters. ResultsThe patients at our institution were followed-up for 114.57 ± 33.52 months. Embolization was performed by balloon-assisted Onyx injection via a single feeding artery. Complete occlusion was achieved in 13 cases and partial occlusion in 1 case. At the final follow-up, all patients were functionally independent (Modified Rankin Scale score of 0–2), with no recurrence. In our review of 70 published cases of DAVFs that underwent endovascular treatment by balloon-assisted Onyx embolization, single- and dual-lumen balloon catheters were used in 33 and 37 patients, respectively. In the former group, there was complete or near-complete occlusion in 32 cases and partial occlusion in 1 case; and in the latter, there was complete or near-complete occlusion in 35 cases and partial occlusion in 2 cases. There were no deaths following endovascular treatment. ConclusionMeasurable and durable outcomes can be achieved by endovascular treatment of DAVFs with the transarterial balloon-assisted Onyx embolization technique, especially in cases with small, distal, and circuitous feeding arteries.

Hemorrhagic risk factors of endovascular onyx embolization of intracranial dural arteriovenous fistulas.

Hemorrhagic complication is a disastrous complication of intracranial dural arteriovenous fistulas (DAVFs) embolization. This study was to analyze the possible risk factors for the hemorrhagic complication caused by endovascular embolization of DAVFs. From January 2012 to July 2016, a total of 267 patients with intracranial DAVFs received endovascular Onyx embolization at our hospital. The demographic information, clinical presentation, angiographic features, endovascular treatment and hemorrhagic complications were reviewed. Univariate and multivariate logistic regression analyses were performed to evaluate the risk factors contributing to the post-procedural hemorrhagic complications. In 267 patients of DAVF treated with endovascular embolization, procedure-related hemorrhagic complication occurred in 12 (4.5%) patients. Univariate and multivariate logistic regression analyses showed that the pial arterial supplier (OR 13.630; 95% CI, 1.556-119.368; P = 0.018), giant venous aneurysm (OR 15.196; 95% CI, 2.505-92.183; P = 0.003) and Onyx volume ≥ 6 ml (OR 1.138; 95% CI, 1.006-1.288; P = 0.040) were significant factors associated with these hemorrhagic complications. Hemorrhagic complications associated with endovascular DAVF embolization are not negligible. The pial arterial supplier, giant venous aneurysm and higher Onyx volume in one session may be risk factors for endovascular DAVF embolization.

Endovascular Embolization of a Lateral Sacral Fistula: 2-Dimensional Operative Video

Spinal dural arteriovenous fistulas are the most common vascular malformations of the spine. They are localized in the sacral spine in 5% to 14% of the cases. They can be fed by the median or the lateral sacral arteries. These lesions present with nonspecific symptoms such as radiculopathy and/or myelopathy, which often leads to a delay in diagnosis. In this video, we present the case of a 65-yr-old gentleman with a lateral sacral dural arteriovenous fistula. The patient was referred to our institution after the outside facility workup was nondiagnostic. He presented with spastic paraparesis and bilateral radiculopathy. After patient informed consent was obtained, we performed a spinal diagnostic angiogram with catheterization and angiography of the internal iliac artery, which revealed the fistula. Onyx (Medtronic, Dublin, Ireland) embolization was performed, which led to a complete occlusion of the fistula. The patient had complete neurological recovery, and at 2-yr follow-up, imaging remained negative for a fistula. In this video, we discuss the nuances and key points related to the epidemiology, diagnosis, and treatment of lateral sacral fistulas.1-3.

Direct transcranial coil and Onyx embolization of a dural arteriovenous fistula: Technical note and brief literature review

Intracranial high-grade dural arteriovenous fistulas (DAVFs) have higher bleeding rates compared to other intracranial vascular malformations. Endovascular treatment is usually recommended for high-grade lesions, aiming at a complete fistula obliteration. However, some patients have vascular abnormalities that limit endovascular access to the precise location of the shunt. Alternative techniques may be considered in this scenario. A middle-aged man presented with intracranial hypertension secondary to a high-grade DAVF. Because of vascular abnormalities precluding transvenous access to the intracranial venous circulation, the patient required treatment by a direct transcranial coil and Onyx embolization of the shunt. Direct transcranial cannulation of a dural sinus is an alternative and effective route for transvenous embolization of DAVFs, especially if abnormal venous anatomy precluding venous access to the required cranial venous system is identified.

Update Onyx embolization for plexiform arteriovenous malformation: Ante-grade drifting technique.

The conventional arteriovenous malformation (AVM) Onyx embolization technique is the extrusion Onyx injection technique, with blood-flow control after a certain distance casting through the head end of the microcatheter. This method has elevated periprocedural AVM bleeding complications. In this study, the authors reported safety and efficacy of an updated ante-grade drifting Onyx injection for plexiform AVM embolization. Between January 2016 and December 2018, 101 consecutive patients with plexiform AVMs were treated with ante-grade drifting Onyx injection. The patients' clinical status was classified using the modified Rankin Scale (mRS). To measure associations, logistic univariate or multivariate regression analyses were used. Complete AVM obliteration was achieved in 51.2% (52/101) of patients. Two (2/101, 2.0%) arterial perforations occurred without causing neurological deficits. In univariate and multivariate logistic regression analyses, younger patient age (odds ratio (OR) = 1.06, 95% confidence interval (CI) 1.01-1.12, p = 0.014), haemorrhagic presentation at admission (OR = 7.14, 95% CI 1.52-33.33, p = 0.013) and low Spetzler-Martin grade (OR = 10.00, 95% CI 3.45-25.00, p < 0.001) were significantly correlated with complete obliteration. Pretreatment mRS was correlated with perforation complication (OR = 3.44, 95% CI 1.05-11.29, p = 0.041) in univariate logistic regression analysis but not in multivariate logistic regression analysis (OR = 2.956, 95%CI 0.745, 11.731, p = 0.123). Patients' clinical status was significantly improved after endovascular AVM embolization. With ante-grade drifting Onyx injection, it was possible to prevent serious bleeding complications and elevated complete embolization rate in plexiform AVMs. Younger patient age, haemorrhagic presentation at admission and low AVM Spetzler-Martin grade were significantly correlated with complete obliteration. Although there is not enough statistical power to show that the pretreatment mRS and the arterial perforation complication have a significant correlation, but its OR value is large, and there may be more data in the future to obtain further conclusion.

Transvenous Onyx Embolization of Carotid-Cavernous Fistulas: Mid- and Long-Term Outcomes.

Objective Endovascular treatment of carotid-cavernous fistulas (CCFs) has been consistently shown to give excellent results and is currently the mainstay of treatment of these complex vascular pathologies. Onyx is currently the most widely used agent, but there has been concern over high rates of cranial nerve (CN) deficits seen in patients with CCF treated with Onyx and paucity of data on long-term outcomes. Methods This is a retrospective analysis of patients who underwent transvenous Onyx embolization between 2011 and 2018. The data collected included demographics, comorbidities, presenting symptoms, CCF morphology, degree of obliteration, procedure-related complications, clinical outcomes, and follow-up. Results A total of seven patients (five females) were included. The median age was 66 years (range: 15-79 years). Median duration of symptoms before treatment was 4 weeks (range: 1-24 weeks). There were three direct and four indirect CCFs. Barrow classification is as follows: A-3; B-3; C-0; and D-1. Immediate complete occlusion was achieved in all cases. There was also one case of immediate postoperative change in CN function (new partial CN VI deficit) that resolved completely at 1-month follow-up. The mean length of stay was 3 days (±2). The preoperative extraocular movement CN deficits had the following outcomes: three resolved; two improved; and one persisted. Proptosis, chemosis, conjunctival injection, and tinnitus were resolved in all patients. The median follow-up was 34 months (range: 10-91 months). Conclusion Transvenous Onyx embolization is a safe and effective treatment of CCFs when technical aspects to reduce complications are performed diligently. Our technique demonstrates safety of the Onyx as a stand-alone embolization for the treatment of CCF.

Endovascular Treatment of Ruptured Enlarging Dissecting Anterior Spinal Artery Aneurysm

Aneurysms of the anterior spinal artery are extremely rare. Unlike intracranial saccular aneurysms, they do not occur at branch points, are typically pseudoaneurysms, and rupture secondary to a dissection. They typically present with subarachnoid hemorrhage and demonstrate clinical and radiographic improvement over time without treatment. We present here the first case to date of a ruptured anterior spinal artery aneurysm with clinical and radiographic progression treated with Onyx embolization. Our patient was unique in the presentation with acute onset of spinal cord injury American Spinal Injury Association B and an extensive thoracolumbar subdural hematoma. An emergent skip-level laminectomy and subdural decompression were performed with no improvement in examination. This was followed by progressive radiographic enlargement of the aneurysm, treated successfully with Onyx embolization. We analyze this case and review the literature on thoracic anterior spinal artery and artery of Adamkiewicz aneurysms.

Transvenous Onyx embolization for dural arteriovenous fistula with concomitant transvenous balloon protection of the venous sinus.

The purpose of this study was to evaluate the technical efficacy and safety of transvenous Onyx embolization for dural arteriovenous fistulas (DAVFs) with concomitant transvenous balloon protection of the venous sinus when transarterial route failed or was not feasible. Between September 2010 and December 2016, thirty-six patients presenting with intracranial DAVFs underwent transvenous balloon-assisted Onyx embolization. The technical efficacy, treatment-related complications, and angiographic and clinical outcomes were reviewed from our prospectively maintained DAVF database. According to the Cognard Classification, 11 patients presented with clinically symptomatic Cognard type I; 11 cases with Cognard type IIa; 10 cases with Cognard type IIb; and 4 cases with Cognard type IIa+b. Complete angiographic occlusion of the DAVFs at the latest follow-up (mean 18 months after transvenous embolization) was achieved in 28 patients (77.8%), near-complete angiographic occlusion with minimal residual fistula in 5 patients (13.9%) and significant flow reduction of the DAVF in 2 patients (5.6%) and residual fistula for further treatment in 1 (2.8%) patient. Total clinical cure or remission of the pretreatment symptoms was achieved in 31 patients (31/36, 86.1%; 26 and 5 cases respectively). Affected venous sinus was preserved in 28 patients, intentionally occluded in 7 patients and gradually occluded in 1 patient. There were no immediate or long-term persistent complications after treatment. Transvenous Onyx embolization of dural arteriovenous fistulas with combined transvenous balloon protection of the venous sinus is safe and effective in achieving high occlusion rate, low embolization-related complications and satisfactory clinical outcomes.

Outcomes of Onyx® Embolization of Type II Endoleaks After Endovascular Repair of Abdominal Aortic Aneurysms

Type II endoleaks (T2ELs) are common following endovascular repair of abdominal aortic aneurysms (EVAR). Embolization with ethylene vinyl alcohol copolymer (Onyx) may present an effective treatment alternative for T2ELs. Due to limited data supporting its use, we sought to analyze outcomes of Onyx embolization for T2ELs. Retrospective review of consecutive patients treated for T2ELs utilizing Onyx embolization agent from 2009-2018. All pre- and post-Onyx intervention CT scans were analyzed for diameter and volume changes with 3D reconstruction software. The primary outcomes were change in maximum AAA diameter and volume. Secondary outcomes included additional interventions, rupture, and mortality. A subset analysis was performed with patients with isolated T2ELs (no other types of endoleaks present). We identified 85 patients (73 males, mean age 77.6±7.6years) who underwent 112 Onyx interventions. Average time to first Onyx intervention after index EVAR was 3.3±2.6years and average sac growth was 6.3±6.7mm. Patients underwent mean 1.3 Onyx interventions using a mean of 4.9±4.7ml for treatment. Three complications occurred (Onyx extravasation, colon ischemia, and access site hematoma). Mean follow-up was 2.5±2.1years after initial Onyx treatment. At the most recent follow-up, sac diameter stabilization was seen in 47% and reduction >5mm was seen in 19%. Sac growth of >5mm was seen in 34% of patients following the first Onyx intervention. In our subset of isolated T2EL, 72% had sac stabilization or reduction >5mm. Four patients experienced a ruptured aneurysm (3 had active type 1 endoleaks). Rupture-free survival was 95% at 5years, and overall survival was 54% at 5years. Notably, increasing Onyx interventions were not associated with sac stabilization or reduction (OR 0.6, P=0.1). On multivariable analysis, AAA sac diameter stabilization or reduction was independently associated with BMI >30kg/m2 (OR 4.2, P=0.01) and having only 1 Onyx intervention (OR 3.8, P=0.02). Onyx for embolization of T2ELs resulted in AAA sac diameter stabilization or reduction in 66% of patients, and up to 72% in isolated T2ELs. Further, increasing Onyx interventions were not associated with either aneurysm sac stabilization or reduction. Given its similar outcomes to other embolization strategies in the literature, Onyx embolization for management of T2ELs needs to be judiciously considered, particularly for T2ELs persisting after an initial Onyx embolization intervention.

Outcome of Endovascular Treatment of Cerebral Arteriovenous Malformations with Ethylene Vinyl Alcohol Coploymer

Abstract Background Cerebral AVMs are very rare lesions, and this rarity contributes to the difficulty of treating them. There is no consensus concerning the method of treatment to be chosen among neurosurgery, radiosurgery or embolization. Onyx embolization could serve as a curative option with accepted morbidity and mortality. The introduction of Onyx and of catheters with detachable tips has no doubt increased the rate of endovascular occlusion, and decreased the risks associated with treatment in our experience. Objective The aim of the study was to assess the outcome of the use of Onyx in the treatment of intracranial AVMs as curative embolization or before neuro- or radiosurgery Patients and Methods This analytical prospective study was conducted on 25 patients who were diagnosed with cerebral arteriovenous malformations and underwent endovascular embolization with EVOH copolymer with curative intent during the study period. Interventional procedures were done in the neuro – endovascular unit, neurosurgery department Ain Shams University Hospitals and associate neuroendovascular unit in El Matarya Teaching Hospital in the period between September 2014 and April 2017. Results Actually comparing these results especially concerning the cure rate along with other studies was somewhat confusing and problematic owing to the diversity in results between studies across the last 15 years. Conclusion For the cases that are not fulfilling these criteria, embolization should be offered as preparing step for other modality of treatment. In our experience, for curative embolization, the AVM should be small sized (&amp;lt; 3 cm), supplied by one vascular territory, with feeders that can tolerate reflux up to 2–3 cm, with clear proximal parts of the draining veins, and not located in deep structures.

Onyx embolization of skull base paragangliomas: a single-center experience.

Skull base paragangliomas are highly vascular tumors that are often embolized before surgical resection; however, the safety and efficacy of preoperative embolization using an ethylene vinyl alcohol copolymer (Onyx; Medtronic, Dublin, Republic of Ireland) in these tumors is unknown. This retrospective cohort study evaluated patient outcomes after preoperative embolization of skull base paragangliomas using Onyx. We retrospectively analyzed data from all patients with skull base paragangliomas who underwent preoperative Onyx embolization at our institution (January 01, 2005-December 31, 2017). Patient, tumor, embolization, and outcomes data were extracted by reviewing inpatient and outpatient clinical and imaging records. Seven patients were studied (5/7 [71%] female), 6 with glomus jugulares and 1 with a glomus vagale. The median age was 52years, and the most common presenting symptom was cranial neuropathy (6/7 [86%]). The tumor vascular supply was from the ascending pharyngeal artery in all 7 cases (100%) with additional feeders including the occipital artery in 5 (71%); internal carotid artery in 3 (43%); middle meningeal, vertebral, and internal maxillary artery each in 2 (29%); and posterior auricular artery in 1 (14%). The median postembolization tumor devascularization was 80% (range, 64-95%). The only postembolization complication was a facial palsy in 1 patient. Preoperative embolization with Onyx affords excellent devascularization for the majority of skull base paragangliomas, and it may facilitate resection of these hypervascular lesions. The advantages provided by Onyx with respect to penetration of intratumoral vessels must be weighed against the risk of cranial neuropathy.

Balloon-assisted Onyx Embolization in the Management of Complicated Dural Arterioevenous Fistula.

Dural arteriovenous fistula (dAVF) is an abnormal vascular communication between the meningeal artery and vein at the dura mater, with frequent recruitment of collateral arterial pedicles. In recent years, Onyx embolization has become the mainstay intervention for dAVF at various locations, although an unfavorable vascular anatomy often limits effective obliteration of the lesion. Balloon assistance may facilitate curable occlusion of the abnormal shunt with Onyx while preserving the patency of the affected sinus, even in complicated dAVFs. We retrospectively reviewed the clinical and angiographic findings of patients with dAVF treated endovascularly in our institution between September 2018 and August 2019. Based on the detailed analysis of individual angioarchitecture, we defined complicated dAVF as lesions for which a complete cure is considered difficult to achieve with simple transarterial Onyx embolization alone, primarily due to a high flow and/or diffuse shunt with or without drainage to the functioning but compromised sinus. We evaluated the preoperative symptoms, anatomical classification, endovascular procedure, radiologic results, and clinical outcomes of these patients. Five patients met our criteria, all of whom were treated with balloon-assisted Onyx embolization (two superior sagittal sinus dAVF, two transverse-sigmoid sinus dAVF, and one torcular dAVF). In four cases, Onyx was injected from a tiny branch of the middle meningeal artery under balloon occlusion of the collateral arteries or balloon devascularization of the competitive inflow. In three cases, balloon sinus protection was performed to prevent the inadvertent occlusion of the vital venous outflow with Onyx. In one case, for the complementary occlusion of the remnant shunt through the previously coiled but recanalized occipital artery, Onyx was injected from the wire lumen of a dual-lumen balloon catheter to avoid undesirable reflux. The angiographic results were an anatomical cure in four cases and near-complete occlusion in one case. No procedural complications were observed in any cases. The clinical outcome was a complete cure in four cases and improvement in one case. Our cases suggest that balloon devascularization can improve the unfavorable flow environment and simplify the vascular anatomy. Balloon sinus protection can support not only securing the patency of the normal venous outflow but also encourage aggressive intervention. Onyx injection via a dual-lumen balloon catheter can augment the controllability of embolization while preventing reflux. Each of these techniques can facilitate safe and effective Onyx embolization in the treatment of complicated dAVFs, and their combination may further expand the therapeutic horizon.

A Case of Curative Onyx Embolization for Tentorial dAVF via Low-flow Feeders with Temporary Balloon Occlusion of High-flow Feeders.

For curative Onyx embolization of dural arteriovenous fistulas (dAVF) with multiple feeders, it is essential to select the optimal target artery as well as to control the blood flow at the fistula point. We report a case of tentorial dAVF (TdAVF) treated by Onyx embolization under flow control using balloon catheters. A 66-year-old male was admitted to our hospital for treatment of TdAVF detected incidentally by MRI, which revealed a dilated and tortuous vein around the cerebellum. Cerebral angiography demonstrated a TdAVF, fed mainly by bilateral middle meningeal arteries (MMA) and bilateral occipital arteries (OA), with the fistula point at the torcular and venous drainage to the two superior vermian veins (SVVs). Onyx 18 was injected from the low-flow feeder of the MMA under flow control by occluding the high-flow feeder of the OA using balloon catheters, obliterating the arteriovenous shunt. In treatment of TdAVF involving low- and high-flow feeders, Onyx embolization via the low-flow feeder with temporary balloon occlusion of other high-flow feeders is a useful method. This technique makes it easier for Onyx to penetrate the fistula point.

Systematic Review of Transcatheter Arterial Embolization of AVM: Indications, Bleeding Complications, Cure Rate, and Long-Term Bleeding Risk.

This study was to assess the proportion of patients that have bleeding complications, cure rates, and long-term bleeding events for each of the indications (monotherapy, pre- stereotactic radiosurgery (SRS), and presurgery) for AVM embolization. Published literature in the PubMed database by May 2016 citing embolization results for AVMs using liquid embolic agents was reviewed. Additional studies were identified through reference searches in each reviewed article. A systematic review was performed to evaluate the bleeding complications, cure rate, and long-term bleeding risk. We identified 30 studies, including 5103 patients. The overall cure rate was 18%. Curative embolization was achieved in 24% of monotherapy, 10% of pre-surgical, and 16% after pre-SRS. In the Onyx group, the cure rate was higher of 25% ( χ2 = 6.25, P < 0.025). Multiple session (≥2) associated with a higher cure rate of 23% (χ2 = 10.53, P < 0.005). The overall bleeding complication rate of transarterial embolization was 5%. The case fatality of bleeding complication was 31%. Onyx and pre-SRS embolization have a higher bleeding complication rate of 8%. The small studies reported a higher cure rate and bleeding complication rate than large studies. Onyx has increased the cure rate and bleeding complication rate of AVM embolization. Multiple sessions are associated with a higher cure rate and do not increase the bleeding complication. Current pre-SRS AVM embolization has a higher bleeding complication rate. There are publication biases between small and large studies.

Transvenous arteriovenous malformation embolization

Transvenous embolization of arteriovenous malformations has emerged as a safe and effective intervention. In carefully selected patients the transvenous approach has shown efficacy similar to that of conventional transarterial routes....

First Line Onyx Embolization in Ruptured Pediatric Arteriovenous Malformations : Safety and Efficacy.

Brain arteriovenous malformations (bAVM) are the main cause of pediatric intracerebral hemorrhage (pICH). Embolization with Onyx (ev3, Irvine, CA, USA) in children with ruptured bAVM has been infrequently reported. The aim of this study was to assess the safety and efficacy profile of Onyx embolization as first line endovascular treatment of ruptured pediatric bAVMs. Children with non-traumatic pICH due to bAVM rupture at apediatric quaternary care center were prospectively enrolled in aregistry and retrospectively analyzed between 2013 and 2018. Clinical and demographic data, treatment modalities and clinical imaging follow-up were retrieved, and detailed procedural data were retrospectively assessed by two investigators. The safety (procedural morbidity and mortality) and efficacy (obliteration and interval rebleeding) were evaluated. In this study 29children treated for abAVM by Onyx embolization were included (14girls, 48%; median age 11.1years, interquartile range, IQR 8.1-12.7years) with atotal of 72endovascular sessions (median of 2sessions per patient IQR 1-3). The AVMs were deeply located in 23patients (79%). No systemic complications occurred, and no child experienced embolization-related persistent neurological deficits. Non-clinically relevant complications were observed during five procedures, unrelated to Onyx. After amean follow-up of 31months from rupture complete obliteration rates were 100%, 89%, 29%, 14% in bAVM Spetzler Martin gradesI, II, III andIV-V, respectively. It was found that Onyx embolization is safe and represents agood option for an initial treatment approach, in asequential treatment strategy for pediatric ruptured brain AVMs. Younger age may not be an argument to deny Onyx embolization.