Liquid Embolic Material Research Articles

Transverse Sinus / Sigmoid Sinus

The transverse sinus(TS)and sigmoid sinus(SS)are common sites for dural arteriovenous fistulas, and an understanding of vascular anatomy is important when developing treatment strategies. In recent years, transarterial embolization, with a liquid embolization material, has become the treatment of choice, preserving the sinus without extensive coil filling of the affected sinus. With this expansion of therapeutic options, we feel that an understanding of the microanatomy has become more important. For example, the exact site where the vein of Labbé joins the TS should be determined. This article focuses on the development and anatomy of the TS and SS and makes points that should be considered when treating dural arteriovenous fistulas.

Comparison of outcomes with/without preoperative embolization for meningiomas with diluted N-butyl-2-cyanoacrylate

BackgroundPreoperative embolization for meningiomas is controversial regarding its effectiveness in reducing intraoperative blood loss and operative time. In contrast, some reports have documented improved surgical outcomes in large meningiomas. In this study, we retrospectively compared the outcomes of craniotomy for meningiomas with/without preoperative embolization with diluted N-butyl-2-cyanoacrylate (NBCA) primarily in a single institution. MethodsData (World Health Organization grade, Simpson grade, maximum tumor diameter, intraoperative bleeding, operative time, history of hypertension, and time from embolization to craniotomy) of patients with initial intracranial meningiomas were compared with or without preoperative embolization from January 2015 to April 2022. ResultsThe embolization group consisted of 56 patients and the nonembolization group included 76 patients. Diluted NBCA (13% concentration for all patients) was used in 51 of 56 patients (91.1%) who underwent transarterial embolization. Permanent neurological complications occurred in 2 (3.6%) patients. Intraoperative bleeding was significantly lower in the embolization group for a maximum tumor diameter ≥40 mm (155 vs. 305 ml, respectively, p < 0.01). In the nonembolization group, for a maximum tumor diameter ≥30 mm, patients with hypertension had more intraoperative bleeding than non-hypertensive ones. ConclusionsDespite its limitations, the present results showed that, under certain conditions, preoperative embolization for intracranial meningiomas caused less intraoperative bleeding. The safety of treatment was comparable with that reported in the Japan Registry of NeuroEndovascular Therapy 3 (JR-NET3) with a complication rate of 3.7% for preoperative embolization of meningiomas, despite the treatment focused on the liquid embolization material.

Transarterial embolization of sinus dural arteriovenous fistula using non-adhesive liquid embolic material.

Objective: The objective is to report our experience of transarterial embolization of sinus dural arteriovenous fistula (DAVF) using non-adhesive liquid embolic material.Materials and methods: In 3 cases of Borden type II sinus DAVFs, a Copernic balloon was used to protect sagittal sinus in one patient, palliative Onyx embolization was performed to protect transverse sinus in one patient and EVAL/DMSO/ethanol mixture (EVAL, SUCCESS, Shandong, China) was used in the last patient.Results: Two Borden type II DAVFs were changed into type I DAVF and one was cured. The dural sinus was patent after successful Onyx embolization in 3 cases resulting in well patient recovery. There were no treatment-related events.Conclusion: Transarterial embolization of sinus DAVF using non-adhesive liquid embolic material could be effective and safe with sinus protection techniques.

A First-in-Human Trial of a New Aqueous Ionic Liquid Embolic Material in Distal Embolization Applications

PurposeA prospective, single-arm, open-label, multicenter, first-in-human, early feasibility study was completed to evaluate the safety and performance of the GPX Embolic Device (Fluidx, Salt Lake City, Utah), a novel liquid embolic agent, for use in the peripheral vasculature when deep distal embolization is desired. Materials and MethodsThe early feasibility study evaluated the use of the device in the peripheral vasculature. Enrollment consisted of 17 patients with diverse embolization needs requiring deep distal vessel/vessel bed occlusion. Technical success, freedom from adverse events (AEs), and handling/performance characteristics were assessed with follow-up at 30 days. ResultsThe trial enrolled 17 patients requiring distal vascular penetration of the embolic agent, including 7 with renal angiomyolipomas, 4 with renal cell carcinomas (primary and secondary), 4 with portal veins needing embolization, 1 with pelvic sarcoma, and 1 with polycystic kidney. In all cases (100%), technical success was achieved with target regions fully occluded on the first angiogram (taken immediately after delivery). Furthermore, the material received high usability ratings, as measured by a postprocedural investigator questionnaire. Most patients (15/17, 88.2%) were free from device-related severe AEs, and there were no unanticipated AEs during the study. Each patient completed a 30-day follow-up evaluation, and sites remained fully occluded in each case where imaging was available (6 [35.3%] of 17 patients had follow-up imaging where all sites were deemed occluded [100%] with a mean of 30.2 days after the procedure). ConclusionsThe results of this first-in-human, early feasibility study demonstrate that the GPX Embolic Device may provide safe and effective embolization for arterial or venous applications where deep distal penetration is desired.

Abstract 031: Onyx versus nBCA in MMA Embolization for cSDH: A Single Center Experience of 234 hemispheres

Introduction There is growing evidence supporting endovascular treatment with middle meningeal artery embolization (MMAE) for the treatment of chronic subdural hematoma (cSDH). We aimed to compare Onyx vs. N‐Butyl cyanoacrylate (n‐BCA) as liquid embolic materials for MMAE. Methods We included all eligible patients undergoing MMAE for cSDH at University of Pittsburgh Medical Center from April 2019 to December 2022. The main outcomes included radiographic resolution of cSDH with at least 50% reduction of hematoma thickness as a surrogate for treatment success in addition to the need for rescue surgical intervention. Additional outcomes including complication rates and hematoma thickness at the last available follow up. Results A total of 195 patients underwent embolization of 234 hemispheres including 39 bilateral procedures and had available data for final analysis (168 (71.8%) in Onyx group vs. 66 (28.2%) in n‐BCA group). There were no significant differences in age, sex, co‐morbidities, prior SDH/evacuation, pre‐operative cSDH thickness, or use of antithrombotic therapy(P&gt;0.05) while concurrent surgical intervention and midline shift showed a statistically significant difference (P&lt;0.05). On last follow‐up imaging, radiographical treatment success defined as ≥ 50% reduction in hematoma thickness was comparable in Onyx and the n‐BCA groups (50.9% vs 54.8%, P=0.6). Similarly, there was no statistically significant difference in the proportion of patients requiring rescue surgery between both groups (4.8% vs. 7.6%, P=0.4). Excluding concurrent surgical intervention patients yielded similar comparable results. Hematoma thickness at late follow‐up was not statistically significant between both group (8.25 (4.8‐12) mm vs 6.9 (3.1‐11) mm, P =0.11). There was no statistically significant difference in procedural complications between both groups (1.2% vs 1.5%, P=0.84). Conclusion Onyx and n‐BCA in MMAE seem to have comparable outcomes when used in the endovascular treatment of cSDH treatment. Further prospective studies with larger sample sizes are needed to confirm these findings.

Feasibility of the Glue-in-Plug Technique Using a Novel Liquid Embolic Material in a Swine Model

PurposeTo evaluate the feasibility of the glue-in-plug (GIP) technique using n-butyl-2-cyanoacrylate‒Lipiodol (NL)–iopamidol (NLI) for short-segment embolization in swine. Materials and MethodsThe renal arteries, left external iliac artery, subclavian arteries, and common carotid arteries were each embolized in 4 swine using the GIP technique under general anesthesia. First, a type I Amplatzer vascular plug (AVP) (1–2 times the target vessel diameter) was deployed in the target artery. Next, the AVP was filled with NL mixture prepared at a ratio of 1:2 (NL12) (n = 11) or with NLI mixture prepared at a ratio of 2:3:1 (NLI231) (n = 11). Angiography was performed before, immediately after, and 1 hour after embolization to assess embolization and migration of the embolic materials. The embolized arteries were also evaluated histopathologically. ResultsThe migration distance of the embolic material beyond the plug tip was significantly shorter in the NLI231 group than in the NL12 group immediately after embolization (6.5 mm ± 4.5 vs 1.0 mm ± 1.8, P = .0024) and 1 hour after embolization (8.4 mm ± 5.6 vs 1.0 mm ± 1.8, P = .0013). Angiography revealed no sign of recanalization of the target vessels in any artery in either group. Mild inflammatory cell infiltration was observed around the arterial wall at the embolization site in all arteries in both groups. ConclusionsThe GIP technique using NLI231 may be a feasible procedure for short-segment embolization based on these short-term results.

Copolymer liquid embolization of dural arteriovenous fistulas: A 20-year single-center experience.

Dural arteriovenous fistulas (DAVFs) with cortical venous drainage (CVD) carry significant risks of cerebral ischemia and intracranial hemorrhage. Endovascular treatment (EVT) using Onyx, a copolymer-based liquid embolic material, has become the preferred approach. However, the optimal treatment strategy for anterior cranial fossa DAVFs remains debated. This retrospective study analyzed outcomes of EVT for DAVFs in a single center from 2002 to 2023. Patient data including demographics, clinical status, angiographic findings, embolization techniques, and outcomes were recorded. The results of the anterior fossa malformations were analyzed separately afterward. A total of 195 DAVFs were included in the study. The most common presenting symptom was hemorrhage (41%), most fistulas were located in the transverse and sigmoid sinus region (48%), and the majority of DAVFs had direct CVD (78%). Transarterial embolization with Onyx was the preferred treatment strategy in majority of cases (92%). Overall, 94% of patients showed improvement or stability on the modified Rankin Scale. Two patients died due to rebleeding after partial DAVF embolization. Onyx demonstrated higher immediate complete occlusion rate compared to other embolic materials (88% vs. 35%). Overall, 91% of fistulas were closed at the last follow-up. Ten anterior fossa DAVFs were treated, resulting in clinical improvement and complete occlusion in all cases. Based on the results of our study, we believe that a cure of DAVFs, including those in the anterior fossa, can be achieved in more than 90% of cases through transarterial Onyx embolization, given long-term clinical experience.

Abstract Number ‐ 106: Particle Versus Liquid Embolic Materials in Middle Meningeal Artery Embolization for Chronic Subdural Hematoma

Introduction Chronic subdural hematoma (cSDH) is one of the most common neurosurgical diagnoses with a high recurrence rate in the aging population. The primary pathologic process is repeated micro bleeding from fragile neo‐vessels supplied by peripheral branches of the middle meningeal artery (MMA). MMA embolization is an efficacious minimally invasive neuroendovascular technique for the management of chronic subdural hematoma. It has demonstrated reduced incidence of re‐bleeding and recurrence of cSDH in elderly patients. Particle and liquid embolic materials are commonly used to devascularize the MMA however studies comparing the safety and outcomes between these two materials are limited. Our objective was to perform a descriptive analysis to investigate differences and outcomes among two most frequently employed materials for MMA embolization. Methods We performed a single center retrospective review of patients ≥ 18 years who had MMA embolization for cSDH between July 2020 and May 2022. The primary safety, radiation dosage, fluoroscopy time, radiographic and clinical outcomes were compared between particle and liquid embolization. A descriptive analysis for continuous and categorical variables was performed using SAS 9.4 version. Results In a cohort of 116, 48 (41.38%) were treated with liquid embolic material and 68 (58.62%) were treated with particle. The median age of the cohort was 73 years in particle group and 73.5 years in liquid embolic group. There was no significant difference in radiation dose or duration among both groups. There was no reported mortality associated to procedure. One patient experienced non‐disabling ischemic stroke in the particle group. Based on imaging follow‐up, three patients in particle group and one in liquid embolic group had asymptomatic recurrence. One patient in each group had symptomatic recurrence requiring hematoma evacuation. Index median size of hematoma was 12 mm in particle group and 11 mm in liquid embolic group. At approximately one month follow up, the median size of hematoma reduced to 6 mm in both groups. Conclusions Our series demonstrates that liquid embolic and particle embolization are equally safe and effective among patients undergoing MMA embolization for management of cSDH.

Abstract Number ‐ 39: Comparison of Clinical and Radiographic Efficacy of Particles versus nBCA/Onyx in MMA Embolization for cSDH

Introduction Middle meningeal artery (MMA) embolization has emerged as a minimally invasive alternative to open surgery for treatment of chronic subdural hematoma (cSDH). Different embolic materials are utilized in this procedure per operators’ discretion; however, limited data currently exists regarding the clinical and radiographic efficacy of these embolic materials, with available studies lumping Onyx and N‐Butyl cyanoacrylate (n‐BCA) into a single group of liquid embolic material. Methods Series of consecutive patients undergoing MMA embolization (MMAE) for cSDH at 2 North American centers (2019‐2021) were included. The primary outcomes included cSDH radiographic resolution of cSDH with at least 50% reduction of hematoma thickness to be considered treatment success. Clinical outcomes were defined as the proportion of patients requiring additional unplanned surgical intervention. These outcomes compared between the particles group, the liquid group which were further subdivided into the n‐BCA and Onyx groups. Results Overall, 185 patients undergoing 198 MMAE procedures (median age 72 years, 27.5% women) were included in this analysis. In this cohort, 42.6% of the procedures were performed utilizing particles embolic material, while n‐BCA and Onyx were utilized in 29.5% and 26.8% of procedures, respectively. On last follow‐up imaging (median 3.5 months), ≥ 50% reduction in hematoma thickness was achieved in 67.7%, 71.1%, and 72.3% in the particles, Onyx and the n‐BCA group, respectively (p = 0.2). There were no differences in the proportion of patients requiring additional unplanned surgery between the groups (p = 0.6). Similarly, there was no difference in procedural complications between the 3 embolic materials groups. Conclusions MMAE for cSDH utilizing particles and liquid embolic materials (including Onyx and n‐BCA) appears to have an overall equivalent safety and efficacy profiles in cSDH treatment. Further studies with larger sample sizes and longer follow‐up are warranted.

Pressure cooker technique in cerebral AVMs and DAVFs: different treatment strategies.

The pressure cooker technique (PCT) was developed to enable safer and more extensive embolization of hypervascular lesions by simultaneously minimizing backflow of liquid embolic materials and thus reduce the risk of non-target embolization of adjacent healthy vessels. We report our experience in applying the PCT to cerebral arteriovenous malformations (AVMs) and dural arteriovenous fistulas (DAVFs) and additionally suggest our technical adjustments. We retrospectively reviewed all patients suffering from AVMs or DAVFs that were treated with the PCT between 2018 and 2020 in two university hospitals. The endpoints of the study were clinical safety and the technical efficacy. The endpoints of the study were clinical safety and the technical efficacy. Clinical safety was the absence of death, major or minor symptomatic stroke, TIA and procedure-related intracranial bleeding (SAH) in the peri-procedural period until dismission. Good clinical outcome was defined as no deterioration of the modified Rankin Scale (mRS) score (comparing the pre- and post-procedural mRS evaluated by a trained neurologist at admission and dismission). The technical efficacy was considered as the complete embolization occlusion of the target vessels of the lesion documented on the final control angiogram. Long-term follow-up evaluation was not intended for this study as it was not available for all patients. Fifteen consecutive patients (6 women; mean age 55 y; range 20-82 y) with seven AVMs and eight DAVFs met the inclusion criteria. The primary clinical safety end point was obtained in all cases as no intraprocedural complications were encountered. All patients had a good clinical outcome with no difference between the pre- and post-mRS scores. The primary efficacy end point was reached in all cases. The PCT is a safe and effective technique in the treatment of cerebral AVMs and DAVFs. Adding an easy and fast step to the procedure, namely the injection of contrast media to test the complete obstruction by the plug, the risk of reflux seems to additionally be reduced.

Outcomes of Particle versus Liquid Embolic Materials Used in Middle Meningeal Artery Embolization for the Treatment of Chronic Subdural Hematoma

Early evidence suggests that middle meningeal artery (MMA) embolization is an efficacious minimally invasive neuroendovascular technique for the management of chronic subdural hematoma (cSDH). Particle and liquid embolic materials are commonly used to embolize the MMA; however, studies comparing the safety and outcomes between these 2 materials are limited. Patients ≥18 years old who had MMA embolization for cSDH between July 15, 2020 and May 1, 2022 were retrospectively identified from a single-center database. The primary safety, radiation dosage, fluoroscopy time, and radiographic and clinical outcomes were compared between particle and liquid embolization. In a cohort of 116, 48 (41.38%) were treated with liquid embolic material and 68 (58.62%) were treated with particle. The median age of the cohort was 73 years in the particle group and 73.5 years in the liquid embolic group. There was no significant difference in radiation dose or duration among both groups. There was no reported mortality associated with the procedure. One patient experienced nondisabling ischemic stroke in the particle group. Based on imaging follow-up, 3 patients in the particle group and 1 in the liquid embolic group had asymptomatic recurrence. One patient in each group had symptomatic recurrence requiring hematoma evacuation. The index median size of hematoma was 12 mm in the particle group and 11 mm in the liquid embolic group. At approximately 1 month follow-up, the median size of hematoma reduced to 6 mm in both groups. Our series shows that liquid embolic and particle embolization are equally safe and effective among patients undergoing MMA embolization for management of cSDH.

Cerebral Blood Vessels and Infection

Infectious intracranial aneurysms(IIAs)are rare cerebrovascular complications of systemic infections induced by microbial infiltration and degradation of the arterial vessel wall. Prospective or population-wide studies of the epidemiology, natural history, or management of IIAs have not been conducted. In this study, we present the epidemiological and angiographical features, management, and outcomes of IIAs based on published case series and retrospective studies. Most IIAs were small in size(< 5 mm), with aneurysms located in the middle cerebral artery followed by the posterior cerebral artery. Endovascular interventions for IIAs have increased since coils, liquid embolic materials, and microcatheter became more sophisticated, allowing them to reach more distal branches. Open surgery is still required in cases with large clots or in cases involving branches feeding the eloquent areas, which cannot be sacrificed. These multimodal approaches for managing IIAs have achieved satisfactory results. Septic cavernous sinus thrombosis is also a rare, life-threatening complication of head and neck infections. Several antibiotics and antivirals are used in combination with anticoagulants. However, no consensus has been reached because of a lack of randomized controlled trials and large population-based studies.

Facial palsy following onyx embolization of a glomus tympanicum tumor: A case report and literature review

The embolization of a glomus tumor (GT) is a known preoperative procedure aimed at decreasing the blood supply to the tumor and reducing operative time and blood loss. Liquid embolic material is the preferable embolic agent. However, the incidence of cranial neuropathy due to denaturation with Onyx is not well established. This report seeks to illustrate the outcomes of a combined preoperative Onyx embolization of a glomus tympanicum tumor and highlight the related complications of facial palsy. A 49-year-old woman developed left-sided facial palsy following the preoperative embolization of a left-sided GT with selective transarterial embolization using ethylene vinyl alcohol (EVOH; Onyx 18), which was complicated with left-sided facial weakness 1 h post embolization. An additional uneventful surgical resection of the GT was performed successfully 72 h later. Embolization material poses a risk of cranial neuropathy. Further studies are recommended to support the knowledge of well-established embolization agents that will provide maximal occlusion while minimizing the risk of complications.

Transvenous embolization of vein of galen aneurysmal malformations using the "Chapot pressure cooker" technique.

Two patients, one 5-year-old and one 7-year-old, both presented with congestive heart failure in the newborn period and were subsequently treated in the newborn period with multiple, staged TAEs with n-BCA for choroidal VGAMs. We achieved progressive reduction in shunting and flow but were unable to accomplish complete closure of the malformation: in both patients, a small residual with numerous perforators persisted. The decision was made to perform TVE using the CHPC. In this technique, a guiding catheter is placed transjugular into the straight sinus (SS). One or two detachable tip microcatheters are advanced to the origin of the SS. Another microcatheter is advanced and the tip placed between the distal marker and the detachment zone of the former. Coils and n-BCA are used to prevent reflux of Onyx. In this study, we recognized two important factors of traditional VGAM treatment that may cause interventionalists to consider the ChPC to treat VGAM: (1) without liquid embolic, deployed coils may not occlude the fistula entirely. (2) There is the concern of causing delayed bleeding should the arterial component of the fistula rupture. ChPC ameliorates these issues by offering complete closure of the fistula with liquid embolic material in TVE.

Onyx™ Cast Fragmentation After Embolization of Endoleaks

Purpose: Endoleaks are common following endovascular aneurysm repair (EVAR), and the liquid embolic material Onyx has been widely used in their treatment. We report our experience of long-term morphological changes of Onyx casts on surveillance imaging. Materials and Methods: We identified 10 patients over 10 years who underwent Onyx embolization in our institution. Morphological changes of Onyx casts were assessed on surveillance radiographs and computed tomography (CT) scans. Relevant outcome data and sequelae were obtained via electronic patient records. Results: Twelve procedures were performed on 10 cases, 9 for type 2, and 1 for a type 1a endoleak. Five cases showed evidence of Onyx fragmentation on follow-up imaging ranging from a single fracture to gross fragmentation with migration of fragments. Of these 5, 3 had achieved primary success but 2 went on to develop recurrence of endoleak. Onyx volume ranged from 4 to 46.5 ml (median 10.5 ml) per patient with larger volumes demonstrating the most marked fragmentation on follow-up. Follow-up ranged from 9 months to 8 years (median 2.25 years). Conclusion: To our knowledge, this is the first report of Onyx fragmentation after endoleak embolization. If long-term morphological stability of the Onyx cast is necessary to maintain aneurysm seal, then Onyx may not offer a permanent solution to some patients with post-EVAR endoleaks. Our study cannot ascertain whether the observed changes were the cause or the effect of ongoing aneurysm growth, persistent endoleak, and/or other forces acting on the solidified polymer, but it raises important questions on the use of Onyx in this setting.

Direct N-butyl-2-cyanoacrylate injections to the head and neck for percutaneous embolized devascularization.

Background: N-butyl-2-cyanoacrylate (NBCA) has been used for vascular malformations since the 1980s; however, few studies have looked at applications, procedural techniques, and outcome throughout many institutions. Herein, we review applications, procedural techniques, previous literature, and outcomes for the use of NBCA specifically through percutaneous technique in treating head and neck vascular pathology.Methods: An extensive literature review using PubMed database with published literature containing “N-butyl-2-cyanoacrylate embolization,” was performed. No date restrictions were used. Cross-checking of articles was conducted to exclude duplicate articles. The articles were screened for their full text and English language availability. We finalized those articles pertaining to the topic.Results: The search yielded 1124 related articles. When comparing surgical resection to embolization with NBCA for cerebral AVMs, complications were similar in both groups and included hemorrhage (15%), residual AVM (6%), and cerebrospinal fluid leak (3%). Their mortality rate was 3% in both groups. Preoperative percutaneous embolization does show improved surgical outcomes.Conclusion: NBCA is a fast-acting liquid embolic material used in the treatment of a variety of vascular malformations and lesions of the head and neck. Investigations surrounding the use of NBCA injections as a new alternative embolic agent began in the 1980’s. Administration of NBCA has been shown to be useful in minimizing intraoperative blood loss and controlling acute hemorrhage. Performing percutaneous embolization with NBCA provides a successful alternative for surgeons when transcatheter embolization techniques may prove to be too difficult to perform. Embolization using NBCA will continue to play in integral role in the treatment of malignant lesions and vascular malformations. Continued research is warranted to improve safety, outcomes, and further develop clinical applications of NBCA.

Abstract P495: Aqua Embolic System: Evaluating the Performance of a New Liquid Embolic System Using a Swine AVM Model

Introduction: Liquid embolic material (LEM) plays an essential role in the treatment of hemorrhagic stroke caused by vascular malformation such as arteriovenous malformations (AVMs). However, currently available non-adhesive LEMs has the problem of catheter entrapment, and also known to have cytotoxicity due to the organic solvents such as Dimethyl Sulfoxide (DMSO). Aqua Embolic System (AES) is a new liquid embolic material, which is mainly composed of multiple polysaccharides. AES, when injected via a microcatheter, immediately forms a solid and elastic hydrogel cast upon exposure to Ca2+ in the bloodstream. The use of organic solvents, e.g., DMSO, is not required. The performance of AES was evaluated using an established AVM model utilizing swine rete-mirabile. Methods: Under general anesthesia, the left ascending pharyngeal artery (APA) of Yorkshire swine (40 kg) was catheterized using a microcatheter (ID:0.013 inches), and AES was slowly injected into the rete-mirabile under fluoroscopy. The following parameters were assessed to evaluate the embolization performance of the AES; 1) the amount of AES required for the complete occlusion of the feeding artery, 2) injection speed, 3) radiopacity during the deployment, and 4) incidence of catheter entrapment after the injection. The same evaluation was performed on the contralateral rete-mirabile and the left renal artery as well. Results: 12 arteries in 4 swine were treated, and all arteries were completely occluded without technical complications. The injected materials immediately formed AES cast in all vessels, followed by the reflux over the tip of the microcatheter. All catheters were withdrawn without any sign of catheter entrapment. The AES mixed with tantalum based contrasts medium showed sufficient radiopacity under fluoroscopy. With the injection speed of 0.02ml/sec, the average volume required was 0.85mL for the APA and 2.9mL for the renal artery. No increased thrombogenicity or vasospasm near the treated lesion was observed during the procedure. Conclusions: AES, which is a DMSO free, non-adhesive polysaccharides-based LEM, may be used as an embolic material for the treatment of hemorrhagic stroke caused by cerebrovascular diseases, such as brain AVM.

Angioarchitecture and Pre-Surgical Embolization of Central Nervous System Solitary Fibrous Tumor/Hemangiopericytoma.

Hemangiopericytomas (HPCs) and solitary fibrous tumors (SFTs) have been categorized as the same disease entity, SFT/HPC, since 2016. SFT/HPC is one of the most highly vascularized brain tumors, distinct from meningioma. The angioarchitecture also differs between these tumors. Understanding these differences can help interventionalists perform presurgical embolization more safely and effectively. Vascular structures were analyzed in eight patients with central nervous system (CNS) SFT/HPCs, all of whom received presurgical embolization. The type of embolic materials used and the complication rates were compared between the CNS SFT/HPC cases and 39 meningioma cases treated within the same period. Characteristic angiographic features of SFT/HPC were identified, and we present their interpretation and utilization to inform embolization strategies. Four angiographic features of SFT/HPCs were identified. 1) Persistence of tumor stain and 2) feeders from branches of the internal carotid artery or vertebral artery were observed in all cases, while 3) connecting feeders (highly dilated vessels that originate from branches of other feeder vessels and run along the surface of one tumor compartment to feed another compartment) were observed in five out of eight cases. 4) Finally, an intratumoral arteriovenous shunt was identified in one case. The frequency of liquid embolic material use was significantly higher in SFT/HPC cases than in meningioma cases. No complications were observed in SFT/HPC cases, and all tumors were effectively removed. The most appropriate presurgical embolization strategies differ between SFT/HPCs and meningiomas depending on the tumor angioarchitecture. A thorough understanding of the vascular anatomy is necessary for safe and effective embolization of SFT/HPCs.

Feasibility and Safety of n-Butyl Cyanoacrylate-Lipiodol-Iopamidol as an Alternative Liquid Embolic Material.

To evaluate the feasibility and safety of n-butyl cyanoacrylate (NBCA)-Lipiodol-Iopamidol (NLI) as a liquid embolic material. In vitro, the ratio of NLI components was adjusted and the configuration of the mixtures was assessed visually in saline. In vivo, 14 wide-necked aneurysms were created on the common carotid and external iliac arteries of four female swine. Under balloon occlusion, 12 aneurysms were embolized with NLI prepared at a NBCA-Lipidol-Iopamidol ratio of 2:3:1 (NLI231), and two were embolized with NBCA-Lipiodol (NL) prepared at a NBCA-Lipiodol ratio of 1:2 (NL12) as a trial group. We performed angiography to evaluate the effectiveness of embolization and adhesion of the embolic material to the balloons or microcatheters. In vitro, NLI231 (33% NBCA) was considered to be the optimal ratio for aneurysm embolization based on its configuration and stability. In vivo, embolization using NLI231 was successful and no adhesion between the embolic material and the balloons or microcatheters was observed in all 12 aneurysms. Embolization with NL12 was impossible in the other two aneurysms due to leakage and adhesion of NL. The configuration of NLI changed at each ratio. NLI231 is a feasible and safe liquid embolic material for balloon-assisted embolization of wide-necked aneurysms in swine.

PHIL Migration to Internal Carotid Artery and Middle Cerebral Artery: Late Mechanical Retrieval with Solitaire AB Stent

AbstractPrecipitating hydrophobic injecting liquid (PHIL) is a novel embolic agent used in the endovascular treatment of arteriovenous malformations (AVM) and arteriovenous fistulas. Complications can occur during embolization with migration of the liquid embolic material to normal vasculature. In these cases, use of a stent retriever is an option for removal of the plug. Herein, we present the case of a patient who presented with a right occipital hemorrhage due to a ruptured occipital AVM fed by the calcarine and parieto-occipital arteries with venous drainage to the straight sinus. Embolization via the anterior circulation through the right posterior communicating artery was attempted but PHIL migrated to right internal carotid artery and middle cerebral artery due to kinking and rupture of the microcatheter. The patient developed mild left hemiparesis. When this complication occurred, no stent retriever was available at our institution and 1 day later, the Solitaire AB stent was used to remove the plug of PHIL successfully, with good reperfusion of the proximal and distal vessels. The patient improved after the procedure and was discharged home without deficit. Mechanical stent retrievers can be used in cases of migration of liquid embolic agents to normal vasculature with good clinical and radiological results.