Transvenous embolization of vein of galen aneurismal malformations using the “Chapot pressure cooker” technique

In some vein of galen aneurysmal malformation (VGAM) patients, transvenous embolization (TVE) is an attractive option, but its safety is unclear. Here we report the first two VGAM patients treated using the Chapot “pressure cooker” technique (ChPC). Methods 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. Results 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. Conclusions 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.

Endovascular Treatment of Cavernous Sinus Dural Arteriovenous Fistulas. Institutional Series, Systematic Review and Meta-Analysis

Purpose Endovascular treatment represents the first-line therapy for cavernous sinus dural arteriovenous fistulas (CS-dAVF); however, different approaches and embolic agents as well as occlusion rates, complications and clinical outcomes are reported among the published series. In this study we performed a comprehensive meta-analysis to investigate clinical and radiological outcomes after endovascular treatment of CS-dAVFs. Methods PubMed, Ovid Medline, Ovid EMBASE, Scopus, and Web of Science were screened for a comprehensive literature review from 1990 to 2020 regarding series of patients treated for CS-dAVF with endovascular approaches. We performed a proportion meta-analysis estimating the pooled rates of each outcome also including data of patients treated in our center. Results A total of 22 studies reporting 1043 patients and 1066 procedures were included. Chemosis was reported in 559 out of 1043 patients (45.9%), proptosis in 498 (41.5%), and ophthalmoplegia in 344 (23.5%). A transvenous embolization was preferred in 753 cases (63.2%) and coils were used in 712 out of 1066 procedures (57.8%). Overall, 85% (95% confidence interval, CI 69.5–96.1%) of patients had a complete resolution of symptoms, while complications occurred in 7.75% (95% CI 3.82–12.7%) with minimal permanent deficits (0.15%). The mortality rate was 1 out of 1043 patients (< 0.001). Conclusion A transvenous coiling is the most common endovascular approach for CS-dAVF, achieving a high percentage of radiological and clinical resolution and low complication rates. Transvenous approaches show less complications than transarterial ones, and coils appear safer than liquid embolic agents.

P-OGC37 Lymphatic embolisation for chylous abdomen following oesophagectomy

Background A 78 year old man underwent an Ivor Lewis oesophagectomy (laparoscopic converted to open abdominal phase, right thoracotomy) for a T2 N2 (3/81) R0 Type II GOJ adenocarcinoma post FLOT neoadjuvant chemotherapy. He developed a chylous abdomen requiring drainage radiologically. A percutaneous lymphatic embolisation was performed which showed a leak in the region of the cisterna chyli which was successfully treated. Methods A lymph node in each groin was cannulated under US guidance using spinal needles and an infusion of Lipiodol was started at a rate of 6ml/hr each side. Lymphatic opacification was monitored under fluoroscopy with contrast having reached the cisterna chyli within 30 minutes. Contrast was seen extravasating near cisterna chyli, confirming an injury at this site. A lumbar trunk lymphatic was cannulated with a Chiba needle and wire enabling positioning of a microcatheter as close to the point of injury as possible. Onyx liquid embolic was used to embolise the feeding lymphatic trunk. Results Post-procedural drain outputs demonstrated an immediate significant drop, with losses of only 300ml/24hr within 48 hours. Drain outputs continued to taper and the drains removed shortly after. The cisterna chyli is typically thought of as a retroperitoneal/para-aortic structure not prone to instrumentation during an ILGO. Despite reviewing the intra-operative footage, a definitive moment/point of injury remains unclear. Conclusions Conservative management of abdominal chyle leak including use of TPN and octreotide is often effective but in sustained large volume ascites(&gt;1000mls/24hr) this is unlikely to succeed. Percutaneous lymphatic embolization can be offered as a treatment option for these patients.

Abstract 1122‐000045: Transvenous Embolization of Vein of Galen Aneurismal Malformations Using the “Chapot Pressure Cooker” Technique

Introduction : There are various procedural techniques described in the literature to treat VGAM: 1) transarterial embolization (TAE) via a transfemoral or transumbilical approach, 2) transfemoral or transtorcular venous coiling, and 3) the combined transarterial and transvenous “trapping” of the fistula. The transarterial technique has permitted our team to obtain total or near‐total obliteration in approximately 80% of cases; however, there is a patient population in whom the residual arterial supply is comprised of small perforators. In these patients, transvenous embolization (TVE) is an attractive option, but its safety is unclear. Here we report the first two VGAM patients treated using the Chapot “pressure cooker” technique (ChPC). Methods : 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 transvenous embolization 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 if necessary, are used to prevent reflux of Onyx. This forces the Onyx to occlude the vein and the most distal arterial segment. Results : Both patients had complete occlusion of the VGAM after ChPC. Conclusions : This is the first report to describe TVE to cure VGAM after multiple sessions of TAE. This is also the first report to apply ChPC to VGAM treatment. 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. Not only is the residual vein blocked, but also the incoming arterial supply which prevents delayed bleeding. In endovascular treatment of VGAM, TVE is feasible option once the dilated vein of Galen becomes small enough. To prevent incomplete occlusion or post‐procedural hemorrhagic complications, the use of the ChPC using DMSO liquid embolic material is a promising and necessary introduction to the neurointerventionalist’s treatment arsenal.

Abstract 1122‐000055: Parenchymal and Subarachnoid Angiogenesis in Patients with Vein of Galen Aneurysmal Malformation

Introduction : Vein of Galen Aneurysmal Malformation (VGAM) is an arteriovenous malformation that accounts for 30% of all pediatric vascular malformations. VGAMs undergo significant remodeling of hemodynamic and structural anatomy due to angiogenesis. These changes not only affect the malformation on a molecular and morphological basis, but may also lead to alterations in planned surgical procedures. It is imperative to better understand the dynamic, angiogenic environment of the cerebrovasculature in order to more effectively treat this disease. Methods : We present 36 cases of secondary angiogenesis in VGAM. We also present three case reports of angiogenesis secondary to VGAM. Results : Pre‐interventional angiogenesis was identified in 16 patients (44.4%) and post‐interventional angiogenesis in 20 patients (55.6%) following a stage of embolization therapy. The cohort of patients with pre‐interventional secondary angiogenesis was significantly older than patients with post‐interventional angiogenesis at initial angiogram (12 months ± 40.1 months vs. 4.0 months ± 5.4 months; p<0.05). Choroidal VGAMs presented with angiogenesis more frequently than Mural VGAMs (4/14 Mural vs 32/42 Choroidal; p<0.01). Angiogenesis was localized to either the left, right, or bilateral thalamus in 2 cases, to the cisternal space surrounding the VOG in 16 cases, and both in 18 cases. Conclusions : Upon identification of secondary angiogenesis, our team’s strategy is to embolize the venous component of the fistula. The ideal strategy in our practice is cannulation of the primary feeder of the malformation, as close to the fistula as possible, and injection of highly concentrated n‐BCA glue (70%‐90%) in a transarterial approach. After multiple rounds of embolization, feeders become less dilated and may be difficult to distinguish from angiogenesis. In this pattern, we use low‐concentrate nBCA (40%‐50%) from an identifiable, proximal feeder and occlude the venous component of the fistula. We identified two patterns of secondary angiogenesis: 1) pre‐interventional angiogenesis identified at the initial diagnostic angiogram, 2) de‐novo, post‐interventional angiogenesis during the staged‐embolization treatment‐course. Occasionally, we noted random bursts of angiogenesis. A combination of the hypoxic environment, inflammation, and hemodynamic alterations to the VGAM caused by liquid embolic/coiling may lead to a burst of angiogenesis that subsides after repeated treatment. We hypothesize that the immature sinuses typically associated with VGAM patients, which experience a decrease in blood flow and subsequently narrow after embolization, may contribute to turbulent blood flow. Development of parenchymal and subarachnoid angiogenesis is common during the multi‐session treatment of VGAM. It represents the response to the angiogenic stimuli released from the draining vein. This angiogenesis can be observed to regress spontaneously or mature as we continue to treat the VGAM. It is unnecessary to embolize secondary angiogenesis outright and it is our recommendation to chiefly target primary feeders of the VGAM as close to the venous component as possible.

Abstract 1122‐000160: Transvenous Embolization Technique: A Modern Strategy for Anterior Ethmoidal Dural Arteriovenous Fistulas

Introduction : Ethmoidal dural arteriovenous fistulae (AVF) are rare intracranial lesions and account for 2–3% of all dAVF. They are often supplied by the ethmoidal or falcine branches of the ophthalmic artery and typically drain into a cortical vein then into the superior sagittal sinus (SSS). Current available treatment options include surgical resection and endovascular embolization via transarterial and transvenous routes. Prior studies have solely compared surgical and transarterial endovascular treatment approaches. Reports of the transvenous approach remain scarce in the literature. Methods : We performed a retrospective review for anterior ethmoidal (AE)‐dAVFs treated with transvenous embolization by our practice between August 2018 and August 2021. Four patients with 5 dAVFs were identified. We describe the presentation, treatment, and outcome of these cases. Results : We describe four patients with AE‐dAVF. Case 1 is a 33‐year‐old man with a previously treated basal ganglia arteriovenous malformation achieving cure. He was lost for follow up for three years and returned with symptoms of peri‐orbital headache and blurry vision. Diagnostic angiography revealed a dAVF arising from the cribriform plate with arterial supply derived from bilateral AE arteries and venous drainage via a common cortical frontal interhemispheric vein to the anterior third of the SSS. Transvenous embolization was achieved and liquid embolic was injected into the vein with retrograde penetration to the fistulous point. Follow‐up angiography revealed obliteration of the dAVF. Case 2 is a 23‐year‐old man with chronic headache who was found to have a right sided ethmoidal dAVF arising from the right ophthalmic artery for which he underwent successful embolization through a transarterial approach. Follow‐up angiography demonstrated occlusion of the treated fistula and new left sided ethmoidal AVF arising from the left ophthalmic artery with a single draining cerebral vein which drains into the anterior third of the SSS. Transvenous embolization was achieved via coiling. Follow up angiography also showed complete occlusion of the dAVF. Case 3 was a 67‐year‐old woman who presented with a Cognard type III right ethmoidal dAVF with arterial feeders through surpra‐orbital branches of the right ophthalmic artery, draining into a frontal cortical vein leading to the SSS. The patient underwent transvenous embolization using coils. Case 4 was a 64‐year‐old woman who presented with scalp tenderness. Diagnostic angiography revealed a left AE‐dAVF. Transvenous embolization with complete occlusion was achieved using a combination of liquid embolic and coil embolization. No adverse events were encountered during or after embolization, but long‐term outcome has yet to be collected for cases 3 and 4. There were no neurologic procedural complications. Conclusions : This small case series shows that transvenous embolization is a feasible, effective, and safe alternative to surgery. Larger prospective studies are needed to further validate this treatment approach in patients with ethmoidal dAVF.

Non-Adhesive Liquid Embolic Agents in Extra-Cranial District: State of the Art and Review of the Literature

This review focuses on the use of “new” generation of non-adhesive liquid embolic agents (NALEA). In literature, non-adhesive liquid embolic agents have mainly been used in the cerebral district; however, multiple papers describing the use of NALEA in the extracranial district have been published recently and the aim of this review is to explore and analyze this field of application. There are a few NALEA liquids such as Onyx, Squid, and Phil currently available in the market, and they are used in the following applications: mainly arteriovenous malformations, endoleaks, visceral aneurysm or pseudoaneurysm, presurgical and hypervascular lesions embolization, and a niche of percutaneous approaches. These types of embolizing fluids can be used alone or in combination with other embolizing agents (such as coils or particles) so as to enhance its embolizing effect or improve its possible defects. The primary purpose of this paper is to evaluate the use of NALEAs, predominantly used alone, in elective embolization procedures. We did not attempt a meta-analysis due to the data heterogeneity, high number of case reports, and the lack of a consistent follow-up time period.

The Two-Step Treatment for Giant Hepatic Hemangiomas

The aim of the present study is to analyze the feasibility and the impact of a two-step approach in the treatment of giant hemangiomas (GH) i.e., exceeding 10 cm in maximum diameter, consisting of transarterial embolization (TAE) followed by laparoscopic liver resection (LLR). Ten patients with 11 GH were treated with TAE and subsequent LLR between 2017 and 2020 (Group A). A matched cohort of 10 patients with GH treated with upfront LLR between 2014 and 2017 was identified for comparison (Group B). Data were analyzed regarding intraoperative and postoperative outcomes, including successful completion of LLR, morbidity, and mortality. Successful microparticle embolization of the GH-feeding arteries was performed in all patients in group A. In three cases a liquid embolic agent (Squid-18) was also injected to obtain complete embolization. No complications were observed after TAE. Successful surgery was performed after a mean time interval of 2.2 days from TAE without any case of conversion to laparotomy. Statistically significant differences between group A and group B were found in intraoperative blood loss (250 ± 200 vs. 400 ± 300 mL, p = 0.039), operative time (245 ± 60 vs. 420 ± 60 min, p = 0.027), and length of stay (5 ± 1 vs. 8 ± 2 days, p = 0.046). Our data suggest that two-step TAE + LLR might be a safe and effective option for surgical treatment of GH >10 cm.

Asystole during Onyx embolization of 64-year-old patient with dural arteriovenous fistula

Asystole or bradycardia is a relatively uncommon side effect seen in patients undergoing endovascular embolization using dimethylsulfoxide based liquid embolic agents. We present a case of a patient who underwent dural arteriovenous fistula embolization and experienced bradycardia during Onyx injection but was stabilized and the procedure was completed successfully.