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Arteriovenous malformations (AVMs) classically feature an intervening nidus of poorly differentiated endothelium. The pillar of modern AVM treatment is intranidal delivery and deposition of various liquid embolic agents such as n-butyl cyanoacrylate, ethylene vinyl alcohol copolymer, and ethanol. These agents are cumbersome to prepare, deliver, and deploy and have been associated with complications related to limited delivery control, nonretrievability, frequent microcatheter exchanges, and nontarget embolization. Coils and other proximal occlusive agents have not been traditionally recommended as sole embolic agents for AVM treatment given the inherent lack of adequate AVM nidus penetration with previous coil technologies. In the present report, we have described a series of three patients with AVMs in whom newer generation, platinum-based, packing coils were used safely and effectively as the primary agent for superselective nidal penetration and embolization.

Bronchial artery embolization (BAE) is considered the first choice treatment for hemoptysis. To our knowledge no cases of BAE using a recent ethylene vinyl alcohol copolymer agent (Squid) have been previously mentioned. Two cases of BAE for remitting hemoptysis using Squid and polyvinyl alcohol particles are reported in this technical note. The final angiographic control confirmed full exclusion of the target territory in both cases. Both patients felt some chest pain immediately after the embolization, not requiring any medications. No more episodes of hemoptysis occurred in the following 3 months after the procedure.

Hemoptysis could be a life-threatening event, especially when the bleeding originates from the arterial pulmonary circulation. The main cause of this type of bleeding is pulmonary artery pseudoaneurysm (PAP), which can be managed by surgical, medical or minimally invasive techniques. This study reports the case of massive hemoptysis in a 75-year-old male patient, with a former history of lobectomy. The initial CT scan showed a giant PAP from a branch of the right middle lobar pulmonary artery, within the right lower lobectomy cavity. An endovascular approach was decided. Subsequently, the feeding artery of the PAP was embolized with detachable coils. The control CT scan showed a persistent opacification of the PAP. The embolization was then completed by injection of Onyx within coils packing, with a complete thrombose of the PAP on control CT scan. This report confirms the safety and efficacy profile of an endovascular approach to treat giant PAP, using a combination of coils and Onyx.

Summary: Background: Type II endoleak (T2EL) after endovascular aortic repair is associated with AAA sac enlargements in up to 25%, reduction of attachment zones and rarely with aortic rupture. Indications for therapy and efficacy of interventions of T2EL are not clearly established. Transarterial embolization with application of ethylene-vinyl alcohol copolymer has been described with varying outcomes. Aim of this study is to evaluate durability of OnyxTM embolization (OE) in T2EL in a consecutive series at a single tertiary vascular center. Patients and methods: Demographic data, technical success, pre- and postoperative aneurysm growth, morbidity, mortality and reintervention rates during hospital stay as well as in follow up were recorded in patients treated with OE for T2EL between 01/2015 and 12/2017. The primary endpoint was defined as persistence or reoccurrence of T2EL (durability of OE). Results: In total 15 patients (78 ± 6 years, 13 men) were treated with OE because of sac enlargement (average growth of 12 ± 8%, n = 12), persistent bleeding after AAA rupture (n = 2) or persistent T2EL with stable but large aneurysm diameter (n = 1). Mean length of stay was 8 ± 11 days. Technical success was 93.3% (n = 14). Inhospital-morbidity was 26.7%, in-hospital- and 1-year-mortality rate were 6.6% (n = 1) and 20.0% (n = 3). T2EL persisted in 20.0% (n = 3) despite of OE. Re-EL-II occurred after 40 (30–114) days in 33.3% (n = 5). Reintervention rate was 13.3% (n = 2, at day 48 and 319). Altogether clinical success with stable aneurysm diameter was achieved in 80.0% (n = 12), but durable elimination of EL was only achieved in 46.7% of patients (n = 7). Conclusions: OE is technically possible in more than 90% of patients but might be associated with severe complications. Durability of this treatment is low, since T2EL persist or reoccur in more than 50% of all patients. OE of T2EL should be reserved for few selected cases.

A 25-year-old man with a venous malformation (VM) along the anterior and posterolateral aspects of the right chest wall presented with progressive enlargement of VM, chest wall pain, and physical disfigurement. Because of the complexity and size of the VM, a staged multidisciplinary team approach, ie percutaneous embolization, followed by surgical resection and tissue-skin grafting was used. The percutaneous embolization was achieved with a combination of liquid embolic agents including n-butyl cyanoacrylate for the superficial cutaneous component and ethylene vinyl alcohol copolymer for the deeper subcutaneous component of the VM. Such a combination can achieve safe occlusion of the VM, facilitate surgical resection without blood loss, and contribute to a cosmetically desirable result.

OBJECTIVE. The purpose of this study was to assess the efficacy and safety of ethylene vinyl alcohol (EVOH) copolymer (Onyx, Medtronic) for embolization for acute renal hemorrhage. MATERIALS AND ME...

Type 2 endoleaks (T2EL) are the most frequent complication following endovascular aortic repair. Multiple studies primarily deal with the technical and clinical success of the embolization of persisting T2EL, thereby revealing controversial outcomes. Current reports rarely focus on the detailed execution of such a complex interventional procedure with respect to the difficult anatomic setting. The present review provides an in-depth depiction and evaluation of the interventional methodology of the embolization of T2EL in the abdominal aorta with use of ethylene vinyl alcohol copolymer (EVOH). Complicating anatomic conditions are taken into account as well as technical and clinical success rates. Using the transarterial approach, there are at least 4 different pathways to access the nidus of a T2EL. CT-guided direct puncture of the aneurysm sac provides an alternative method of high technical success. EVOH with its slow solidification characteristics enables good control to achieve complete filling of the T2EL. During the intervention, however, it remains difficult to meet exactly the embolization endpoint, especially in large T2ELs. T2EL embolization using EVOH is an effective treatment with low major complication rates when conducted by skilled interventionists with detailed knowledge of diverse complex access routes. · Many roads lead to Rome to access the nidus of a T2EL including diverse complex transarterial pathways and direct aneurysm sac puncture.. · Ethylene vinyl alcohol co-polymer enables good control for slow filling of the nidus with low risk of major complications.. · Identification of the embolization endpoint remains difficult during the procedure and may result in secondary interventions.. · Successful T2EL embolization requires detailed knowledge of all access routes to the nidus and skilled handling of liquid embolics..· Nolte-Ernsting C, Mecklenbeck F, Stehr A. Embolization of Type 2 Endoleaks in the Abdominal Aorta Using Ethylene Vinyl Alcohol Copolymer. Fortschr Röntgenstr 2021; 193: 1426 - 1435. Typ-2-Endoleaks (T2EL) stellen die häufigste Komplikation nach endovaskulärer Implantation einer aortoiliakalen Prothese dar. Es existieren zahlreiche Studien überwiegend zu technischen und klinischen Erfolgen der Embolisation von persistierenden T2EL mit kontroversen Ergebnissen. Jedoch finden sich nur wenige Berichte zum detaillierten Ablauf dieser komplexen interventionellen Prozedur in schwieriger anatomischer Umgebung. Die vorliegende Übersichtsarbeit legt den Schwerpunkt auf die ausführliche methodische Darstellung und Bewertung des interventionellen Vorgehens bei der Embolisation von T2EL in der Bauchaorta unter Berücksichtigung der komplizierten anatomischen Gegebenheiten sowie der technischen und klinischen Erfolgsraten. Als Flüssigembolisat wird Ethylen-Vinylalkohol-Copolymer (EVOH) verwendet. Bei transarteriellem Vorgehen existieren mindestens 4 verschiedene Zugangsmöglichkeiten zum Nidus des T2EL. Alternativ empfiehlt sich eine CT-gesteuerte Direktpunktion des Aneurysmasacks als Methode mit hoher technischer Erfolgsquote. EVOH ermöglicht aufgrund seiner langsamen Aushärtung eine gute Kontrolle, um das Ziel der kompletten Auffüllung des T2EL zu erreichen. Während der Intervention ist es jedoch schwierig, den Embolisationsendpunkt exakt zu treffen, insbesondere bei großen T2EL. Die Embolisation von T2EL mit EVOH stellt in der Hand erfahrener Interventionalisten mit detaillierten Kenntnissen über diverse komplizierte Zugangsmöglichkeiten eine effektive und komplikationsarme Behandlung dar. · Viele Wege führen nach Rom, um den Nidus eines T2EL zu erreichen, einschließlich diverser komplexer transarterieller Zugangspfade und der Direktpunktion des Aneurysmasacks.. · Ethylen-Vinylalkohol-Copolymer ermöglicht eine kontrollierte, langsame Auffüllung des Nidus bei niedrigem Risiko für Major-Komplikationen.. · Die Identifikation des Embolisationsendpunktes während der Prozedur ist schwierig und kann Sekundärinterventionen zur Folge haben.. · Die erfolgreiche Embolisation eines T2EL erfordert detaillierte Kenntnisse über alle Zugangsmöglichkeiten zum Nidus sowie Erfahrung und Geschick im Umgang mit Flüssigembolisaten..· Nolte-Ernsting C, Mecklenbeck F, Stehr A. Embolization of Type 2 Endoleaks in the Abdominal Aorta Using Ethylene Vinyl Alcohol Copolymer. Fortschr Röntgenstr 2021; 193: 1426 – 1435.

Background To report our preliminary experience with preoperative portal vein embolization (PVE) using liquid ethylene vinyl alcohol (EVOH) copolymer. Methods Retrospectively review of patients with primary or secondary liver malignancies scheduled for extensive hepatectomy after the induction of future liver remnant (FLR) hypertrophy by right or left PVE with EVOH as the only embolic agent between 2014 and 2018 at two academic centers. Cross-sectional imaging liver volumetry data obtained before and 3-6 weeks after PVE were used to assess the FLR volume (FLRV) increase, degree of FLR hypertrophy and the FLR kinetic growth rate (KGR). Results Twenty-six patients (17 males; mean age, 58.7±11 years; range, 32-79 years) were included. The technical and clinical success rate was 100%. PVE produced adequate FLR hypertrophy in all patients. Embolization occurred in all targeted portal branches and in no non-target vessels. The %FLRV increased by 52.9%±32.5% and the degree of FLR hypertrophy was 16.7%±6.8%. The KGR was 4.4%±2.0% per week. Four patients experience minor complications after PVE which resolved with symptomatic treatment. The resection rate was 84.5%. One patient died during surgery for reasons unrelated to PVE. Conclusions Preoperative PVE with EVOH copolymer is feasible, safe, and effective in inducing FLR hypertrophy.

Objective To evaluate the safety and efficacy of ethylene vinyl alcohol (EVOH) copolymer for the treatment of a variety of peripheral vascular pathologies. Results Between October 2010 and October 2017, 43 patients who underwent total 54 EVOH embolization procedures for the treatment of peripheral vascular pathologies were included. The cases which involved the use of EVOH for the treatment of nonvascular, neurologic, ophthalmologic, otolaryngologic or head-neck pathologies were excluded. The demographic data, technical and clinical success rates, and procedure-related details and complications were obtained. The most common indications for EVOH embolization were type II endoleaks (n = 18) and peripheral arteriovenous malformations (n = 14). The majority of cases (62.5%) used EVOH without any adjunct embolic material. The results of this study showed 100% technical success rates and 89% clinical success rates. No events of nontarget embolization or other procedure-related complications were noted. The mortality & morbidity rates were 0%. The loss to follow up rate was 16% (9 /54). The mean follow-up period was 134 days (range, 30 to 522 days). Conclusion The single institutional experience supports the safety and efficacy of EVOH embolization in the treatment of various peripheral vascular conditions.

BackgroundRecently, middle meningeal artery (MMA) embolization has emerged as a potentially safe and effective method of treating chronic subdural hematoma (cSDH).ObjectiveTo report a single-center experience with MMA embolization and examines the type of embolic material used, the extent of penetration, and the number of MMA branches embolized.MethodsA retrospective analysis of all patients with MMA embolization from 2018 through 2019 was performed. A failed outcome was defined as either surgical rescue and/or greater than 10 mm of hematoma residual or reaccumulation following embolization.ResultsOf 35 patients, surgery had failed for 9 (26%) and initial conservative treatment had failed for 6 (17%). Of 41 MMA embolizations, including those in six patients with bilateral cSDH who underwent bilateral MMA embolization, 29 (72%) were performed using ethylene vinyl alcohol copolymer (Onyx), 7 (17%) using particles, and 5 (12%) using n-butyl cyanoacrylate. Both the anterior and posterior MMA divisions were embolized in 29 cases (71%); distal penetration of these branches was achieved in 25 embolizations (61%). Twenty-six (63%) cSDHs completely resolved. Complete resolution was seen in 22 of 29 hematomas (76%) in which both anterior and posterior MMA branches were occluded versus 4 of 12 (33%) following single-branch embolization (p=0.014). Embolization of one cSDH (2%) failed.ConclusionMMA embolization of cSDHs appears to be both safe and efficacious. Furthermore, embolization of both the anterior and posterior MMA branches may be associated with increased odds of complete resolution.

Backgrounds/Aims Despite the advances in identifying risk factors, improving operative technique, and postoperative patient care, pancreatic leakage after pancreatic resection remains a highly debated topic. The aim of this study is to describe our technique and our initial experience with the intraoperative embolization of the main pancreatic duct with an Ethylene Vinyl Alcohol Copolymer (Onyx®). Methods Two patients of 63 and 64 years underwent pancreaticoduodenectomy for a cholangiocarcinoma of the extrahepatic bile duct and a pancreatic adenocarcinoma, respectively. At the time of pancreatic parenchyma resection, a Wirsung duct was identified and catheterized. A wirsungography was done and then, embolization with Onyx® was carried out under fluoroscopic control. Results Neither of the patients developed a postoperative pancreatic fistula. They were discharged to home on the 17th and 18th postoperative day, respectively. At the last follow-up, no recurrence was found. The two patients became diabetics; both needed the support of supplementary pancreatic enzymes. Conclusions To our knowledge, we are the first to describe this technique, which seems safe and reliable. Studies on this subject with more patients are needed to confirm the validity of this procedure.

Purpose The purpose of this study was to determine retrospectively the safety and technical success rate of embolization using ethylene vinyl alcohol copolymer (Onyx ® ) for persistent type 1A endoleaks after chimney endovascular aneurysm repair (EVAR) for complex aortic aneurysms. Material and methods Nine consecutive patients (6 men, 3 women) with a mean age of 78.6 years (range: 62–87 years) presenting with persistent type IA endoleaks after chimney EVAR and an increase of aneurysm size were treated using transarterial embolization with Onyx ® . Results Technical success was obtained in all patients (100%) and no complications were observed. Mean follow-up was 16 months (range: 3–35 months). Primary clinical efficacy was obtained for 8/9 patients (89%) and primary technical efficacy for 6/9 patients (67%). Secondary clinical efficacy was 100%, and secondary technical efficacy was 78%. Conclusion Our results suggest that arterial embolization using Onyx ® appears as a feasible and safe endovascular procedure of type IA endoleaks after chimney EVAR, although further validation is now required.

Purpose To retrospectively evaluate the safety and efficacy of embolization of persistent type II endoleaks occurring after abdominal endovascular aneurysm repair (EVAR) using ethylene vinyl alcohol copolymer (Onyx ® ). Material and methods Between 2008 and 2016, 28 consecutives patients (25 men, 3 women) with a mean age of 75.3 years ± 9 (SD) (range: 59–90 years) were treated for 29 persistent type II endoleaks with increasing aneurysm size > 5 mm occurring after EVAR. A total of 35 embolization procedures were performed using Onyx ® , via a transarterial route ( n = 25) or direct puncture ( n = 10), with or without additional metallic coils. The endpoints were to evaluate the clinical efficacy, corresponding to the stabilization or decrease of aneurism size, and the technical efficacy, corresponding to the ability to complete the embolization. Results No severe complications were observed during and after embolization. The primary and secondary clinical efficacies were 75% (21/28) and 96.4% (27/28), respectively. Overall primary technical efficacy rate was 58.6% (17/29), greater for transarterial technique (72.8%) than for direct puncture (14.3%) ( P = 0.01). Secondary technical efficacy was 72.4% (21/29), with no differences between transarterial (81.8%) and direct puncture (42.8%) ( P = 0.06). Conclusion Embolization with Onyx ® of type II endoleaks after EVAR appears a safe and effective procedure.

Purpose To report preliminary experience with angiomyolipoma (AML) transcatheter arterial embolization using ethylene vinyl alcohol (EVOH) copolymer liquid embolic agent. Materials and Methods Embolization was performed in 22 consecutive patients (mean age, 53.5 y; 16 women and 6 men) for symptomatic AMLs or AMLs > 4 cm. Mean AML size before treatment was 7 cm (range, 3.5–13 cm). Superselective embolization of all lesions using microcatheters was performed; EVOH copolymer was the only embolic agent used. Data collected included volume of EVOH copolymer used, AML size before and after treatment, bleeding control, rebleeding, renal function, and complications. Results Twenty-seven embolizations were performed for 25 AMLs. In 3 patients, embolization of 2 different AMLs was performed. A mean volume of 2.5 mL (range, 1–8 mL) of 6% EVOH copolymer was administered per lesion. Of embolizations, 17 (63%) were elective, and 10 (37%) were urgent. For urgent cases, primary and secondary bleeding control rates were 80% and 100%, respectively. Two urgent embolizations had early rebleeding from different previously treated vessels and a successful second embolization was performed. Mean follow-up time was 37.7 months (range, 5–124 months). Rate of postembolization syndrome was 18.5%. Mean size reduction of 45.7% ± 21.5 over the maximum length of the AML before treatment was achieved. No AML regrowth occurred during follow-up. Minor and major complication rates were 7.4% and 0%, respectively. No rebleeding and no renal function impairment occurred during follow-up. Conclusions AML embolization with EVOH copolymer is feasible, safe, and effective. EVOH copolymer could be another embolic option for AML treatment.

Direct stick embolization (DSE) of high-flow peripheral arteriovenous malformations (AVMs) has previously been reported using n-butyl cyanoacrylate and ethanol. The use of ethylene vinyl alcohol copolymer (Onyx; Covidien, Plymouth, Minn) through this delivery route has been extremely limited, particularly in the peripheral interventional realm, owing to concerns about technique and conduit for delivery, skin discoloration, and ulceration. We describe three patients with relatively focal, symptomatic, congenital high-flow AVMs of the upper and lower extremity treated successfully by multifaceted approaches including transvenous coil embolization of the nidus venous outflow, transarterial embolization, and DSE of the AVM nidus with Onyx. Successful delivery of Onyx into the AVM nidus was achieved without nontarget embolization. Sustained symptomatic relief without recurrence or associated complications was achieved at 1 month, 3 months, and 6 months of follow-up. Nidus embolization is a key technical maneuver for optimal treatment of high-flow AVMs, although it is not always easily achievable by the transarterial route in more extensive, convoluted angioarchitectural varieties. With appropriate technical considerations and precautionary measures, Onyx can be safely and effectively delivered through DSE into the AVM nidus with satisfactory short-term and midterm clinical outcomes. This maneuver expands the armamentarium of the treating vascular surgeon facing complicated peripheral AVMs.

BACKGROUND Cervico-mediastinal hemangiomas in adulthood are rare and slow-growing vascular tumors. The optimal treatment for giant hemangiomas is controversial. In asymptomatic cases, clinical observation is generally recommended. METHODS We report the transoral resection of a pharyngolaryngeal hemangioma (diameters of 44 × 56 × 39 mm) with tracheal involvement and mediastinal extension. Clinically, the patient had throat foreign body sensation, severe dyspnea and stridor. The hemangioma was first embolized by injecting ethylene-vinyl alcohol copolymer (Onyx) transorally, and then the obstructive aspect of the tumor was resected with a bipolar and ultrasonic clamp (ThunderBeat®, Olympus). RESULTS Two months after surgery, nasal fiberendoscopy showed complete disappearance of the vascular mass at the larynx and hypopharynx, with a normal mobility of the larynx. CONCLUSION In symptomatic patients, surgical reduction of large pharyngolaryngeal hemangiomas may be feasible by direct embolization and transoral ultrasonic resection. Both may provide an almost bloodless surgical field. © 2017 Wiley Periodicals, Inc. Head Neck 39: 1239-1242, 2017.

Purpose: To evaluate the feasibility, safety, and outcome of transcatheter embolization using ethylene vinyl alcohol copolymer (EVOH) of type I endoleaks associated with endovascular abdominal aortic aneurysm repair. Patient Population and Methods: Retrospective chart review was performed to identify 8 consecutive patients who had undergone EVOH embolization for type I endoleaks between 2012 and 2015. The primary approach used to access the endoleak was the perigraft technique, where the endoleak itself is catheterized at the anastomotic site. Results: Six type Ia and 2 type Ib endoleaks were treated. In 2 patients, a direct transabdominal approach was used to access the endoleak because it was inaccessible via the perigraft approach. Coils were used in addition to EVOH in 5 cases. Residual endoleak was noted in 1 case, whereas 2 patients developed a recurrent type I endoleak during follow-up. No EVOH complications were observed. The 5 remaining patients demonstrated freedom from endoleak and reintervention at a mean follow-up of 6.9 months. Conclusion: Type I endoleaks can be safely and effectively treated by embolotherapy with EVOH. Larger endoleaks resulting from grossly undersized endografts appear to be unsuitable for EVOH embolization.

Endovascular aneurysm repair (EVAR) is associated with late complications including the development of endoleaks as major complications. Type II endoleak is the consequence of collateral retrograde flow from the aortic branches; generally from the lumbar arteries, inferior mesenteric artery, or middle sacral artery. The method and the ideal timing for the treatment of endoleaks remain controversial. We are presenting a case of successful treatment of a large type II endoleak using embolization with large amount of Onyx copolymer via a percutaneous transfemoral route without any adverse outcome . A significant advantage of Onyx as opposed to glue is that it may be injected for a long period of time (20–60 minutes) with a lower risk for microcatheter entrapment. This case report suggests that much higher amount of Onyx can safely be used if needed to seal large endoleaks without adverse event.

This is a case report regarding the postoperative complication of pseudoaneurysm of the facial artery likely due to mechanical injury after a bilateral sagittal split osteotomy (BSSO). This article will discuss diagnosis, management, embolization therapy using Onyx (ethylene vinyl alcohol copolymer in dimethyl sulfoxide – DMSO) and review the literature on pseudoaneurysm formed after bilateral sagittal split osteotomy. We will also discuss the common embolic agents and apparent adverse reaction of local infection that may be due to the presence of residual Onyx in the soft tissues.

Background and PurposeLiquid embolic agents (LEAs) are the determinant tool for successful embolization of cranial arteriovenous shunts. There are few currently available LEAs. The aim of the study was to summarize our initial experience with a recently introduced non-adhesive ethylene vinyl alcohol (EVOH) copolymer based LEA (Menox 18) in the endovascular treatment of cerebral arteriovenous malformations.MethodsFrom April 2018 to November 2018, 24 patients harboring cerebral arteriovenous malformations underwent endovascular embolization with Menox 18. Clinical features, angiographic results, procedural details, complications, and follow-up details were prospectively collected and retrospectively analyzed.ResultsCurative embolization in one endovascular session was achieved in 14/24 (58.3%) of the treated patients. Partial embolization was achieved in 10 patients (42.6%) in whom staged treatment with radiosurgery or microsurgical resection was planned. No mortality was recorded in our series. Clinical complications after embolization occurred in 1/24 (4.66%) patients. No technical complications were notedConclusionsOur pilot study suggests that the Menox embolization system offers similar technical and clinical results in comparison with the other currently available LEAs. Further studies with larger cohorts and long term follow-up data are needed to fully evaluate its efficacy

OBJECTIVEThe primary goal of the treatment of cerebral arteriovenous malformations (AVMs) is angiographic occlusion to eliminate future hemorrhage risk. Although multimodal treatment is increasingly used for AVMs, periprocedural hemorrhage after transarterial embolization is a potential endovascular complication that is only partially understood and merits quantification.METHODSSearching the period between 1990 and 2019, the authors of this meta-analysis queried the PubMed and Embase databases for studies reporting periprocedural hemorrhage (within 30 days) after liquid embolization (using cyanoacrylate or ethylene vinyl alcohol copolymer) of AVMs. Random effects meta-analysis was used to evaluate the pooled rate of flow-related hemorrhage (those attributed to alterations in AVM dynamics), technical hemorrhage (those related to procedural complications), and total hemorrhage. Meta-regression was used to analyze the study-level predictors of hemorrhage, including patient age, Spetzler-Martin grade, hemorrhagic presentation, embolysate used, intent of treatment (adjuvant vs curative), associated aneurysms, endovascular angiographic obliteration, year of study publication, and years the procedures were performed.RESULTSA total of 98 studies with 8009 patients were included in this analysis, and the mean number of embolization sessions per patient was 1.9. The pooled flow-related and total periprocedural hemorrhage rates were 2.0% (95% CI 1.5%–2.4%) and 2.6% (95% CI 2.1%–3.0%) per procedure and 3.4% (95% CI 2.6%–4.2%) and 4.8% (95% CI 4.0%–5.6%) per patient, respectively. The mortality and morbidity rates associated with hemorrhage were 14.6% and 45.1%, respectively. Subgroup analyses revealed a pooled total hemorrhage rate per procedure of 1.8% (95% CI 1.0%–2.5%) for adjuvant (surgery or radiosurgery) and 4.6% (95% CI 2.8%–6.4%) for curative intent. The treatment of aneurysms (p = 0.04) and larger patient populations (p < 0.001) were significant predictors of a lower hemorrhage rate, whereas curative intent (p = 0.04), angiographic obliteration achieved endovascularly (p = 0.003), and a greater number of embolization sessions (p = 0.03) were significant predictors of a higher hemorrhage rate. There were no significant differences in periprocedural hemorrhage rates according to the years evaluated or the embolysate utilized.CONCLUSIONSIn this study-level meta-analysis, periprocedural hemorrhage was seen after 2.6% of transarterial embolization procedures for cerebral AVMs. The adjuvant use of endovascular embolization, including in the treatment of associated aneurysms and in the presurgical or preradiosurgical setting, was a study-level predictor of significantly lower hemorrhage rates, whereas more aggressive embolization involving curative intent and endovascular angiographic obliteration was a predictor of a significantly higher total hemorrhage rate.

The endovascular approach is the standard treatment of vein of Galen malformations (VOGMs,) however the morbidity and mortality rates of VOGMs treated by embolization are still significant. Embolization with ethylene vinyl alcohol copolymer (EVOH) by a dual-lumen balloon (DLB) is a promising. In the present case we demonstrated two strategies of transarterial (TA) embolization of a mural type VOGM presenting with two direct shunts. The first shunt was embolized using coils to reduce the flow through the shunt, following by an EVOH injection which resulted in the complete occlusion of that shunt. The second shunt was embolized also with EVOH but through a DLB. In the second embolization a very precise cast of EVOH could be created resulting in a complete occlusion of the VOGM. This case demonstrated the advantages of DLB compared to other embolization techniques

Background and purpose A frequently reported drawback of ethylene vinyl alcohol copolymer-based liquid embolic agents is the production of artifacts in diagnostic imaging. New embolic agents, such as Precipitating hydrophobic injectable liquid (PHIL; MicroVention, Tustin, CA, USA), are supposed to induce significantly fewer artifacts. The purpose of this study is to assess the degree of artifacts induced by the liquid embolic agents Onyx (Medtronic Neurovascular, Irvine, CA, USA) and PHIL in conventional computed tomography (CT), cone-beam CT and magnetic resonance imaging (MRI) in an experimental in vivo model. Materials and methods In 10 pigs the rete mirabile was embolized with Onyx ( n = 5) or PHIL ( n = 5). After embolization, conventional CT, cone-beam CT and MRI were performed. The degree of artifacts was graded qualitatively (five-point scale; for CT and MRI) and quantitatively (HUs of well-defined regions of interest (ROIs); for CT only). Results Artifacts were significantly more severe for Onyx both in the qualitative (e.g. conventional CT: 2 versus 5 (medians); p = 0.008) and in the quantitative image analysis (e.g. cone-beam CT: standard deviation of a ROI near to the embolic agent cast, 94 HU versus 38 HU (medians); p = 0.008). Neither Onyx nor PHIL produced any apparent artifacts in MRI. Conclusion PHIL produces fewer artifacts than Onyx in conventional CT and cone-beam CT in an experimental in vivo model.

Background/Objective: Compliant dual-lumen balloon microcatheters have been used to perform balloon-assisted embolization (BAE) of brain arteriovenous malformations (AVMs) with ethylene vinyl alcohol copolymer (Onyx). However, vessel rupture and microcatheter retention have been reported from BAE using these microcatheters. Using an extra-compliant balloon microcatheter (Scepter XC; Microvention, Tustin, CA, USA) could help avoid pial vessel rupture during BAE. We herein report our experience using this balloon microcatheter for BAE. Methods: This retrospective study included patients who underwent BAE of brain AVMs at our institution between June 2012 and March 2017. Results: The extra-compliant Scepter XC balloon microcatheter was used for BAE of brain AVMs in 23 patients aged 44.3 ± 16.7 years (range 0–65 years). A total of 40 intracranial vessels (39 pial arteries and 1 pial vein) were catheterized and embolized during 30 separate sessions. In all instances, the balloon microcatheter could be successfully advanced to the AVM nidus. A mean volume of 2.4 ± 1.7 mL (range 0.65–4.6 mL) of Onyx was injected per session. There were no instances of vessel rupture, microcatheter retention, or stroke. Conclusion: Utilization of the extra-compliant balloon microcatheter results in safe and effective BAE, which adds to the growing experience with BAE for AVM treatment.

Purpose To evaluate the endovascular use of ethylene vinyl alcohol (EVOH) copolymer (Onyx; ev3 Endovascular, Inc, Plymouth, Minnesota) for the treatment of acute peripheral nonneurologic hemorrhage. Materials and Methods MEDLINE and PubMed databases were searched for articles published in English from 1946 to August 2014 describing patients treated for hemorrhage with EVOH copolymer outside of its usual neurovascular applications. Additional cases were collected from the bibliographies of relevant articles. Full-text articles were obtained. Demographic data, clinical presentation, underlying etiology, culprit vessel, endovascular treatment, outcomes, and follow-up times were obtained. Results The literature search yielded 19 relevant articles. Cases of 131 patients (87 men, 44 women; mean age, 61 y ± 19.2) describing the treatment of 151 lesions were reviewed. The most common categories of arterial lesions were gastrointestinal (n = 53) and bronchial (n = 40) in origin. In 14 cases, EVOH copolymer was employed after failure or rebleeding following the use of a different embolic agent. Average follow-up time was 12.0 months. EVOH copolymer was the sole embolic agent used in 105 patients. Rebleeding after treatment with EVOH copolymer occurred in 10 patients. There were 2 technical failures. One patient died of multiorgan failure in the setting of persistent hemoptysis. Complications included 2 nerve injuries and 2 minor strokes. Conclusions Embolization of acute hemorrhage in the peripheral vasculature was safe and effective with EVOH copolymer.

Onyx(®) (ev3, Irvine, CA, USA) is a liquid embolic agent composed of ethylene vinyl alcohol copolymer dissolved in dimethyl sulphoxide used for the treatment of intracranial arteriovenous malformations. Onyx is a preferred embolizing agent due to its unique properties, non-adhesive nature, and durability. In addition to its approved intracranial application, Onyx is also being used successfully in extracranial embolization in areas including extracranial aneurisms and vascular malformations, trauma, gastrointestinal bleeding, and neoplasms. Because of its increasing utilization, it is important for reporting radiologists to be able to recognize its extracranial appearance across different imaging techniques and to be familiar with its uses. The goal of this review is to describe the extracranial uses of Onyx and its appearance in various extracranial locations at radiography and CT, while providing didactic examples. Onyx appears radiodense at CT and plain radiography and has a curvilinear pattern following the expected path of the vessel embolized. At CT, Onyx creates streak artefact that may obstruct the view of surrounding tissues consistent with descriptions of other tantalum devices.

Over the past two decades, endovascular embolization has become a fundamental part of a multidisciplinary approach for the treatment of intracranial arteriovenous malformations (AVMs). Several embolic agents are now an intrinsic part of the neurointerventional armamentarium. However, none has represented as remarkable an improvement as the introduction of ethylene vinyl alcohol copolymer (EVOH). In conjunction with n-butyl cyanoacrylate (NBCA), EVOH has revolutionized the endovascular management of intracranial AVMs because of its ability to systematically deliver a sufficient volume of the embolic agent to the nidus and pedicles without extension into the venous drainage. The clinical decision to treat an AVM is facilitated by preoperative risk stratification; the first question to be addressed is whether to treat the AVM; and, if so, the second question is how to treat it. Endovascular EVOH embolization is primarily applied as an adjunct treatment to microsurgical resection or radiosurgery. Few cases are amenable to angiographic cure by embolization alone. The goal of this chapter is to describe the pertinent properties, endovascular techniques, and pitfalls for the endovascular management of intracranial AVMs using EVOH.

Introduction Embolization of brain AVMs by injecting Ethylene Vinyl Alcohol Copolymer (Onyx) has been facilitated with dual lumen balloon micro-catheters. Balloon-assisted embolization can improve the efficacy of AVM embolization by preventing excessive reflux of Onyx. However, there have been instances of vessel rupture or microcatheter retention with use of the compliant balloon microcatheter. We hypothesized that using an extra-compliant balloon microcatheter (Scepter XC, Microvention, Tustin, CA) would result in less vessel trauma and prevent pial vessel rupture upon inflation, while retaining the advantages of balloon assisted Onyx embolization. Herein, we report our experience using an extra-compliant balloon microcatheter for embolization of brain AVMS. Materials and Methods This retrospective study was performed by reviewing the medical records and imaging studies of all patients who underwent AVM embolization at our institution between June 2012 and March 2017. Results The extra compliant balloon microcatheter was used for endovascular pre-operative/pre-radiosurgical embolization of brain AVMs in 31 patients (21 male and 10 female ) aged 44.3 + 16.7 years (range: 1-65 years) A total of 40 intracranial vessels (39 pial arteries and one pial vein) were catheterized for injection of Onyx through the balloon microcatheter in these patients. The balloon was not pre-inflated ex-vivo but simply purged of air to improve trackability.In all instances, the balloon microcatheter could be successfully advanced to the nidus of the AVM. A mean volume of 2.1 cc (Range= 0.65 -4.6 cc ) was injected at each instance. There was no incidence of vessel rupture, catheter retention, or stroke. Conclusion The utilization of the extra-compliant balloon microcatheter results in safe and effective balloon assisted embolization. These results add to the growing experience of balloon assisted embolization for AVM treatment. Disclosures: B. Jagadeesan: 2; C; Microvention, Medtronic. A. Grande: 2; C; Medtronic, Integra. R. Tummala: None.

To evaluate safety, technical and clinical success of embolization of type II endoleak (T2 EL) using ethylene-vinyl alcohol copolymer as embolic agent alone or in combination with others materials. From March 2007 to March 2015, 104 patients presented T2 EL during follow-up. A total of 21 patients met the criteria for treatment. T2 EL was treated with TAE (n = 18), DPSI (n = 10) or laparoscopic ligature of the inferior mesenteric artery (n = 1). DPSI was considered in case TAE was unsuccessful (8/18 patients). Ethylene–vinyl alcohol copolymer was used as embolic agent in 12 patients: alone in 5 cases, in association with glue and with glue and thrombin in 3 and 2 cases, respectively, during TAE. Onyx was injected in two cases of embolization performed with DPSI: in one case alone and in the other in combination with thrombin and glue. Technical success rate was 100%. Immediate clinical success was 91.7%; in one patient CEUS revealed persistent T2 EL, decreased if compared with that before the procedure. Secondary clinical success was 91.7%; until today, in one patient T2EL is persistent, nevertheless, the sac diameter remained stable. No major or minor complications were registered. Onyx could be an ideal embolic agent for endovascular and percutaneous embolization of T2 EL.

We present a technical development of the endovascular treatment technique for vein of Galen aneurysmal malformation, using Onyx™ (ethylene vinyl alcohol copolymer) delivered under flow control through double-lumen balloon microcatheters.An 11-month-old patient that initially presented with increasing head circumference was diagnosed with mural type vein of Galen aneurysmal malformation. Complete cure was obtained in a single endovascular treatment session. Onyx was delivered simultaneously through two double-lumen balloon microcatheters (Scepter™, Microvention, Terumo Group). In both arterial feeders, balloon inflation occluded the high-flow arterial-venous shunting and thus facilitated the controlled propagation of the embolic product in the afferent artery and the shunt point while preventing distal migration into the venous system.Two years post-procedure, MR imaging showed persistent occlusion of arterial-venous shunts with complete regression of the venous dilatation. On clinical examination, the patient had no neurological deficits, and no cognitive impairment was detected at neuropsychological testing.The use of double-lumen balloon microcatheters for flow control during delivery of Onyx represents a viable alternative for the endovascular treatment of vein of Galen aneurysmal malformations.

^^ Purpose: To report a single-center experience with transcatheter embolization of type I endoleaks using the liquid embolic agent Onyx, an ethylene vinyl alcohol copolymer. Methods: Eight patients (4 men; mean age 74.8 years, range 63–86) with 10 type I endoleaks (6 abdominal and 4 thoracic) diagnosed 2 days to 9 years after endovascular repair were treated with Onyx embolization because cuff extension was precluded by an insufficient landing zone in 6 cases and an unsuitable aortic diameter in 2. Endoleaks were accessed with a 4-F diagnostic catheter and a coaxially introduced dimethylsulfoxide-compatible microcatheter. Onyx-34 was predominantly applied due to its high viscosity; patent side branches were coil embolized prior to Onyx delivery in 3 cases. Results: Technical success of the procedure was achieved in all cases. The mean volume of Onyx used for abdominal endoleaks was 11.8 mL (range 3.0–25.5) and 19.4 mL (range 4.5– 31.5) for thoracic endoleaks. The average duration of the procedure was 76.7 minutes (range 34.5–110.6), and the average radiation dose area product was 18.8 cGy*cm 2 (range 10.6–55.8). Reperfusion of the endoleak was detected in one case 2 days after the procedure. A second case showed an occluded endoleak but a small trace of contrast between the aortic wall and the stent-graft. Non-target embolization was not found in any case. Mean follow-up was 13.2 months (range 8–24). The mean reduction in diameters for thoracic aneurysms after 6 and 12 months was 0.4 and 0.9 cm, respectively, and 0.6 and 1.2 cm, respectively, for abdominal aneurysms. Conclusion: Transcatheter embolization of type I endoleaks using Onyx is a simple, safe, and sustainable treatment option with a high primary success rate for cases in which stentgraft extension is not possible. The benefit of additional coil embolization remains uncertain. J Endovasc Ther. 2014;21:162–171

The purpose of our study is to report our experience with the use of an ethylene vinyl alcohol copolymer (Onyx) in an off-label fashion for the treatment of type II endoleak after endovascular repair of the thoracic (TEVAR) and abdominal (EVAR) aorta.A retrospective review of patients with type I and/or II endoleak treated with Onyx was performed. Data regarding the technical, clinical, and imaging outcomes were collected. Technical success was defined as decreased or eliminated endoleak on the first imaging follow-up. Clinical success was defined as unchanged or decreased aneurysm sac size on subsequent follow-up.Eighteen patients (15 male, 3 female) with a mean age of 79 years (range 69-92) met inclusion criteria (16 abdominal aortic aneurysm, 2 thoracic aortic aneurysm). Sixteen patients had type II endoleak, and 2 had complex type II endoleak with a type I component. The interval between endograft placement and treatment was a mean of 30 months. Direct sac treatment approach was used in 13 patients; transarterial approach was used in 3 patients. Seven patients required the use of coils, N-butyl cyanoacrylate glue, or Amplatzer vascular plugs. The average volume of Onyx used per treatment was 5.6 mL (range 2.5-13). Duration of imaging follow-up was 0.75-72.5 months (mean 32.8). Sixteen of 18 (88.9 %) patients had initial technical and clinical success. Two of 18 patients (11.1 %) were initial technical failures, and 1 remained a failure despite a second treatment and attempted surgical ligation. Eight of 18 (44.4 %) of patients eventually required a second intervention, 5 (27.8 %) of them due to delayed clinical failure. Complications included 1 psoas hematoma, 1 transient L2 nerve paresis, and 1 intraperitoneal Onyx leak; all of these were without clinical sequelae.Onyx with or without coil/glue/Amplatzer plug embolization is safe and useful in the treatment of type II endoleak after TEVAR and EVAR. However, long-term clinical and imaging follow-up is needed for early detection and management of recurrence of the primary endoleak or the development of new, secondary endoleaks or enlargement of the aneurysm sac.