Selective arterial temporary flow arrest with balloons during transvenous embolization for the treatment of brain arteriovenous malformations: a feasibility study with MRI-monitored adverse events

BackgroundThe technique of endovascular transvenous embolization for brain arteriovenous malformations (AVMs) has emerged in the last 8 years as a very promising therapeutic alternative for otherwise incurable cases. Selective temporary flow arrest during transvenous endovascular embolization (TFATVE) is a novel adaptation of our previously described transvenous approach, which employs hyper-compliant balloons intra-arterially for the selective occlusion of arterial feeders during ethylene vinyl copolymer (EVOH) injection, in order to reduce intra-nidal pressure and increase nidi occlusion rates.MethodsWe performed a feasibility study of the TFATVE technique between January 2016 and April 2020. Consecutive patients were included. All patients had at least one axial brain MRI or CT in the first 48 hours following intervention, and at least one brain MRI scan within the first postoperative month, in order to detect both silent and clinically evident adverse events. Patients’ demographics, angio-architectural characteristics, total injection and procedure times, angiographic and clinical outcomes were analyzed.Results22 patients underwent TFATVE during transvenous endovascular treatment of brain AVMs. Among them, 86.4% were high Spetzler-Martin’s grade. Good clinical outcome (modified Rankin Scale <2) was achieved in 95.5% of the cases, with 0% of procedure-related mortality and 4.5% of clinically significant, procedure-related morbidity. Total occlusion of the nidus was achieved in >90% of the cases at the end of the procedure and angiographic stability was achieved in all cases; 100% of the cases had angiographic cure at follow-up.ConclusionsTFATVE seems a safe and effective technique when conducted in carefully selected patients in highly specialized centers.

Cavernous sinus dural arteriovenous fistula accessed through a straightened superficial temporal vein

Background: Transvenous embolization through the inferior petrosal sinus (IPS) is the most common treatment procedure for cavernous sinus dural arteriovenous fistula (CSDAVF). When the IPS is inaccessible or the CSDAVF cannot be treated with transvenous embolization through the IPS, the superficial temporal vein (STV) is used as an alternative access route. However, the approach through the STV is often challenging because of its tortuous and abruptly angulated course. We report a case of recurrent CSDAVF which was successfully treated using a chronic total occlusion (CTO)-dedicated guidewire and by straightening the STV. Case Description: A 63-year-old woman was diagnosed with CSDAVF on examination for oculomotor and abducens nerve palsy. She was initially treated with transvenous embolization through the IPS. However, CSDAVF recurred, and transvenous embolization was performed through the STV. A microcatheter could not be navigated because of the highly meandering access route through the STV. By inserting a CTO-dedicated guidewire into the microcatheter, the STV was straightened and the microcatheter could be navigated into a shunted pouch of the CS. Finally, complete occlusion of the CSDAVF was achieved. Conclusion: If an access route is highly meandering, the approach can be facilitated by straightening the access route with a CTO-dedicated guidewire.

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.

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 1122‐000061: Initial Experience Using the Transvenous Embolization for Intracranial Arteriovenous Malformations in a Reference Endovascular Center

Introduction : Transvenous embolization (TVE) is used in cases of arteriovenous malformations (AVMs) with specific characteristics such as small size (<3 cm), deep location, single draining vein and the absence of adequate feeders. High complete obliteration rates have been reported. Therefore, our study aimed to analyze our initial experience using the TVE for treatment of AVMs. Methods : Between May 2018 and January 2021, consecutive patients who underwent TVE of AVMs were selected. Demographics, radiological and clinical variables were collected. The modified Rankin Scale (mRS) was used to determine clinical outcomes and was dichotomized (good clinical condition: mRS £2; poor clinical condition: mRS >2). Complete obliteration was defined as the total absence of the nidus and vein, subtotal obliteration was defined as the embolization of >95% of nidus and partial obliteration was defined as the embolization of <95% of nidus. Procedure‐related complications were defined as those that occurred during the procedure and were divided as intraoperative rupture and thrombosis. Results : Twenty‐one patients harboring 21 AVMs were evaluated. Fourteen patients (67%) were women. The mean age was 24.5 ± 14.1 years (7 – 48 years). A good preoperative clinical condition was present in 20 patients. Twenty AVMs were ruptured (95.2%). The most frequent locations were thalamus/basal ganglia in 6 patients (29%), followed by temporal/insular in 5 patients (24%). Spetzler‐Martin grades III, II and I were present in 11, 9 and 1 patients, respectively. The mean number of feeders was 2.1 per AVM. The feeders arised from the MCA in 9 cases, followed by PCA in 5 cases, ACA and AChoA in 3 cases, AICA in 2 cases, and ECA and PCom in 1 case, respectively. The mean number of veins was 1.3 per AVM. Deep venous drainage was present in 12 cases (57%). The mean size of the AVM nidus was 15.7 ± 7.8 mm (3.7 – 34 mm). Previous trans‐arterial embolization was done in 10 patients (47.6%). Pre‐embolization hematoma evacuation was done in 4 patients (19%). An immediate complete obliteration was achieved in 18 patients (85.7%), whereas a subtotal and partial obliteration were achieved in 2 and 1 patients, respectively. A poor post‐operative clinical condition occurred in 4 patients (20%). Procedure‐related complications occurred in 4 patients (20%): 3 cases with intra‐operative rupture of the AVM nidus and 1 case of a thrombus in the M1 treated with stent retriever. Mortality occurred in 3 patients (14.2%) of which two presented intra‐operative rupture with intracerebral hematomas that required decompressive craniectomy. One patient presented a post‐operative bleeding of the AVM nidus that required external ventricular drainage and decompressive craniectomy. Follow‐up angiography was done in 4 cases with total obliteration of all the cases (100%). Conclusions : The transvenous approach has emerged as an alternative to trans‐arterial approach with high grades of immediate total obliteration rates, but with potential procedure‐related complications. Thus, this technique should be used in selected cases in order to achieve complete cure rates.

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.

Abstract 1122‐000110: Transvenous Embolization in Vein of Galen Malformations as the Last Procedure

Introduction : Vein of Galen Malformations (VOGM) are a rare, congenital, vascular malformation representing <1% of all arteriovenous malformations. Treatment is typically performed in infancy and transarterial embolization (TAE) is the most common treatment method. While conventional methods allow for a total or near‐total obliteration in 80% of cases, there is a subset of patients for whom TAE is ineffective (E.g. the residual arterial supply is through small feeders non‐amenable to TAE). In these cases, transvenous embolization or coiling (TVE) is the technically simplest approach. We assessed the immediate angiographic and clinical outcomes of our VOGM cases treated with TVE. All relative technical details are reported. Immediate angiographic outcomes and clinical outcomes are reported. Methods : A retrospective review of our institutional database was performed to identify all VOGM patients who underwent TVE as the final‐stage procedure between January 2004 and December 2020. Results : We describe a cohort of 13 patients, one of whom underwent partial TVE for palliative measures and was excluded. All of the 12 patients that met our eligibility criteria had undergone more than 3 transarterial embolizations with nBCA. The mean age of our cohort was 8.2 (SD: 6.3) years. Ten patients were treated with coils and two with the Chapot “Pressure cooker” (ChPC) Technique. In these two cases, predicting hemorrhage post‐procedurally proved difficult; as a result, we attempted to occlude the remaining arterial supply using transvenous ChPC. Complete immediate angiographic obliteration was achieved in nine patients. Stereotactic radiosurgery was performed in 2 of the remaining patients and full obliteration was achieved. Immediate post‐procedural (within 48 hours) hemorrhagic complications were noted in two patients treated with coils: one of these ended in mortality and the second suffered from significant neurological impairment. In total, eight patients had normal development, three had a moderate delay with hemiparesis and one patient died. Conclusions : To the best of our knowledge, this is the first report of TVE being used as a final‐stage cure attempt for VOGMs after multiple TAE sessions. We advocate that TVE for the treatment of VOGMs is a feasible option as a final‐stage attempt for cure. It is particularly effective if the dilated VOG becomes small enough. To prevent incomplete occlusion and reduce the risk of post‐procedural hemorrhagic complications, the ChPC technique using liquid embolic material should be considered.

Abstract 1122‐000117: Transcranial Arterial Embolization of an dAVF: A Case Report

Introduction : We detail the management of a woman with a posterior fossa dAVF (dural arteriovenous fistula) that was unable to be treated by standard transarterial or transvenous embolization or microsurgical ligation. She underwent craniotomy for surgical exposure and direct access of her left middle meningeal artery followed by microcatheter embolization with favorable results. Methods : This is a case report, which describes a case of a difficult to access dAVF. Results : A 72 year‐old woman presented with vertigo, nausea, and vomiting one week following a fall. CT head disclosed cerebellar vermis intraparenchymal hematoma and CT head angiography was suspicious for underlying vascular malformation. Diagnostic cerebral angiogram demonstrated extensive tentorial and suboccipital dural arteriovenous fistula (dAVF) fed by branches of both middle meningeal and occipital arteries with direct cortical venous drainage and venous aneurysmal ectasia directly adjacent to the vermian hemorrhage (ruptured Cognard grade 4). Left vertebral artery angiogram demonstrated excessive tortuosity of vertebral enlarged posterior meningeal artery, which was unable to be catheterized sufficiently beyond its origin despite different microwires and microcatheters due to tortuosity. Transfemoral venous approach was also attempted, however, this was also unsuccessful and decision was made to proceed with microsurgical treatment. The following day a suboccipital craniotomy was performed, but was ultimately aborted due to nearly uncontrollable bleeding from bony exposure and dural access secondary to severe venous hypertension. The next day percutaneous endovascular treatment was attempted a second time. A small right middle meningeal artery (MMA) contribution to the fistula was embolized with liquid embolic but, again because of excessive tortuosity and insufficient microcatheter access, right MMA occlusion occurred without embolic agent reaching the fistula. Similar access related difficulties due to tortuosity were encountered in accessing the left middle meningeal and occipital arteries contributing to the fistula. Repeat transvenous access was also attempted from the occipital and right transverse sinuses, but microcatheter access to the fistula was unable to be established beyond the venous outflow from the aneurysm, and, given the risks of hemorrhage related to embolization of the venous outflow without occluding arterial inflow into the ruptured aneurysm, transvenous embolization was not performed. A few days later, after the patient was given time to recover from the prior procedures, the patient underwent left temporal craniotomy in a hybrid operating room/interventional radiology suite for direct cannulation of the left MMA. Localization of the craniotomy site over the left MMA access point was planned by transfemoral cerebral angiogram and a transcarotid/peripheral access kit was used to catheterize the left MMA directly following surgical exposure. An .017 microcatheter was advanced close to the fistula point using standard biplanar roadmap fluoroscopy, and Onyx embolization of the fistula was performed to complete occlusion, without complication. Conclusions : For cerebrovascular disorders that are inaccessible by traditional endovascular and surgical means, a hybrid approach should be considered.

Transvenous embolization of a cerebrospinal fluid–venous fistula for the treatment of spontaneous intracranial hypotension

Cerebrospinal fluid–venous fistula is an increasingly recognized cause of spontaneous intracranial hypotension.1 The site of the leak is between the dural sleeve around a spinal nerve root and the surrounding foraminal veins. In appropriately investigated patients, transvenous embolization of the draining foraminal and paraspinal veins has been shown to be an effective way of treating the disease, with low periprocedural morbidity, improvement in symptoms and radiological appearances.2 Video 1 shows the technique employed in a typical case using Onyx (Medtronic, Minnesota, USA) to embolize a CSF–venous fistula at the right T10 neural foramen.Video 1