The transvenous pressure cooker technique: A treatment for brain arteriovenous malformations

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

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

Direct Puncture of the Superficial Temporal Artery in Embolization of a Scalp Arteriovenous Fistula: A Case Report

We describe a minimally invasive endovascular approach to treat an arteriovenous fistula of the scalp. We performed a direct puncture of the lesion through the patient's scalp for liquid embolic agent injection along with external compression of the superficial temporal artery to perform a "manual pressure-cooker technique." The combination of these minimally invasive techniques resulted in an excellent clinical and radiographic outcome.

Microcatheters with extra-long detachable tip: A promising treatment option in dural arteriovenous fistulas

PURPOSE

Treating cerebral dural arteriovenous fistulas (dAVFs) by transarterial embolization is an established endovascular approach but no data exist regarding the utility of using the newly introduced microcatheters with extra-long detachable tip. Aim of our study was to evaluate the value of these microcatheters and, additionally, of combining them with the simplified pressure cooker technique.

METHODS

Twenty-nine patients treated for dAVF with transarterial embolization were enrolled. In a subgroup of fifteen patients the simplified pressure cooker technique was additionally applied. Demographics and characteristics were collected for patients and dAVFs and procedural details reviewed. The association between covariates and binary-coded occlusion status was evaluated.

RESULTS

Microcatheter navigation into the target pedicle as well as application of the simplified pressure cooker technique were successful in all cases. Complete dAVF occlusion was reached in 69.0% at a single stage. In case of complete dAVF occlusion, embolization via only one pedicle was enough. Subgroup analysis revealed a higher occlusion status (80%) if using the simplified pressure cooker technique than if not (57%) but reached not significance level.

CONCLUSION

Using microcatheters with extra-long detachable tip for dAVF embolization seems to offer a safe and effective treatment option with exceptional high occlusion rate at a single stage. The high navigability facilitates catheterization of a single selected target pedicle that is often enough to reach complete dAVF occlusion. Combining these microcatheters with the simplified pressure cooker technique turned out to be safe and easy to handle and might allow an increasing dAVF occlusion rate.

Transvenous embolization of hemorrhagic brain arteriovenous malformations: Case reports and literature review

Introduction

Transvenous embolization (TVE) has been proven to be safe and feasible as an alternative management of brain arteriovenous malformations (AVMs). We presented four patients with a hemorrhagic brain AVM who underwent TVE and reviewed the relevant literature.

Methods

Four patients underwent TVE of a hemorrhagic brain AVM in our center between July 2019 and July 2020. We retrospectively collected and analyzed the clinical and imaging data of these patients and those reported in previously published studies.

Results

Four patients with a hemorrhagic brain AVM were included. Nidus sizes ranged from 0.79 to 2.56 cm. Spetzler-Martin grade ranged from grade II to grade III. The AVM nidus was located in a deep brain region in three patients. One patient underwent TVE alone and three underwent combined transarterial and transvenous approaches. Digital subtraction angiography (DSA) demonstrated complete obliteration of the vascular malformation after embolization in all four patients. Three patients were independent [modified Rankin Scale (mRS) score ≤ 2] at discharge. All four patients were independent at the last follow-up. AVM obliteration was confirmed in all four patients at the last angiographic follow-up.

Conclusion

Transvenous embolization can be used as an alternative treatment for contemporary management of brain AVMs, appropriate patient selection is essential to achieve a good clinical outcome.

Perioperative Complications of Transvenous Embolization of Ruptured Intracranial Arteriovenous Malformations

Purpose

To investigate the perioperative complications of transvenous embolization of ruptured intracranial arteriovenous malformations.

Materials and Methods

A total of 27 patients with ruptured intracranial arteriovenous malformations underwent transvenous embolization were enrolled from November 2016 to May 2020 in our prospective database. Perioperative complications and angiographic characteristics were analyzed retrospectively.

Results

Complete disappearance of the nidus occured in 22 (88%) of 25 patients with technically feasible AVMs immediately after embolization. Two cases were partially treated by transarterial embolization due to the failure of microcatheter placement into the draining vein. Seven (25.9%, 7/27) patients had perioperative complications, including three cases of intraoperative hemorrhage, three cases of postoperative hemorrhage and one case of ischemic infarction. No significant differences in complication rates between patients with nidus ≥3 cm and <3 cm (P = 0.659), eloquent area and non-eloquent (P = 0.137), deep location and superficial (P = 0.637), deep venous drainage and cortical vein (P = 1.0), the number of venous drainage (P = 0.49), the angle of draining vein entering venous sinus <90° and ≥90° (P = 1.0), aneurysms (P = 0.058) and the time between hemorrhage and TVE (P = 1.0) were found. Three of these patients received ventriculostomy, two of which received lumbar drainage treatments at the same time, and four patients just received conservative management. Good outcomes (mRS ≤ 2) at the 1-month evaluation were achieved in 5 of the patients who had complications, but poor outcome (mRS = 5) at the 1-month evaluation was in 1 patient, and 1 lethal complication occurred.

Conclusion

The most common complication of AVMs with transvenous endovascular embolization is cerebral hemorrhage. The prevention of complications may improve the efficacy of AVM embolization, but the current quality of evidence is low and limited in guiding policy development and improving the TVE for AVMs. It is, therefore, necessary to develop clinical research programs in this field.

Endovascular Management of Intracranial Dural AVFs: Principles

Intracranial dural AVFs are abnormal communications between arteries that supply the dura mater and draining cortical veins or venous sinuses. They are believed to form as a response to venous insults such as thrombosis, trauma, or infection. Classification and management are dependent on the presence of drainage/reflux into cortical veins because such drainage markedly elevates the risk of hemorrhage or venous congestion, resulting in neurologic deficits. AVFs with tolerable symptoms and benign drainage patterns can be managed conservatively. Intolerable symptoms, presentation with hemorrhage/neurologic deficits, or aggressive drainage patterns are indications for intervention. Treatment options include microsurgical disconnection, endovascular transarterial embolization, transvenous embolization, or a combination. This is the first in a series of 3 articles on endovascular management of intracranial dural AVFs, in which we outline the principles and outcomes of endovascular treatment.

Endovascular balloon-assisted liquid embolisation of soft tissue vascular malformations: technical feasibility and safety

Purpose

Arteriovenous malformations (AVMs) are abnormal communications between arteries and veins without an intervening capillary system. The best endovascular treatment option for these is unclear and may involve multiple staged procedures using a variety of embolic materials. We report our initial experience using a modified version of a previously published neurointerventional technique to treat soft tissue AVMs with single-stage curative intent.

Materials and methods

Soft tissue AVMs treated endovascularly using either sole arterial or combined arterial and venous balloon-assisted techniques with liquid embolic agents were retrospectively identified over a 3.5 year period (January 2017 to June 2020)) at two centres. Clinical, pre-operative radiological, procedural technical and post treatment details were recorded.

Results

Seven patients were treated for symptomatic soft tissue arteriovenous malformations. These AVMs were located in the peripheral limbs (five), tongue (one) and uterus (one). Curative treatment was achieved in 6/7 patients with one patient requiring a second treatment approximately 1 year later. A variety of liquid embolisation agents (LEAs) including sclerosants and polymers were used. Clinical success rate was 100% following treatment. One patient experienced expected temporary post-operative tongue swelling requiring tracheostomy occurred following embolisation of the lingual AVM. A minor complication in a second patient was due to an access site haematoma developed following treatment of the hand AVM requiring surgical intervention. No long-term sequelae or additional complications were observed.

Conclusion

Endovascular arterial and venous balloon assisted LEA embolization of soft tissue AVMs with curative intent is feasible. This technique may provide an alternative treatment option for achieving durable occlusion for complex soft tissue AVMs.

Hand-compression pressure cooker: an innovative variation of an existing technique with two example cases

The pressure cooker technique was originally ideated to obtain wedge-flow conditions during arteriovenous malformation or arteriovenous fistula embolisation. The anti-reflux plug created with coils or glue around the tip of a detachable microcatheter enables a continuous injection with a more in-depth penetration. Here we describe two illustrative cases performed with a variation of the technique that we describe as the hand-compression pressure cooker technique.

Adenosine-induced transient circulatory arrest in transvenous embolization of cerebral arteriovenous malformations

Due to advances in interventional techniques, the transvenous approach may present an effective treatment option for embolization of brain arteriovenous malformations (AVMs). Contrary to the transarterial method, the transvenous approach can only be utilized in a specific subset of patients and is not suitable as a standard procedure for all AVM lesions. While this technique can be helpful in certain patients, careful patient selection to ensure patient safety and favorable clinical outcomes is important. However, especially in high-flow AVMs, targeted deposition of embolic materials through a transvenous access can be challenging. Therefore, a temporary flow arrest may prove helpful. Transient cardiac arrest by use of adenosine has been applied in cerebrovascular surgery but is not common for endovascular embolization. Adenosine-induced arrest and systemic hypotension may be a feasible, safe method to reduce flow and help endovascular transvenous embolization of certain AVMs. Our study evaluated the efficiency and safety of adenosine-induced circulatory arrest for transvenous embolization of cerebral AVMs.

Comparing N-hexyl cyanoacrylate (Magic Glue) and N-butyl cyanoacrylate (NBCA) for neurovascular embolization using the pressure cooker technique: An experimental study in swine

BACKGROUND

The pressure cooker (PC) technique uses a second microcatheter to produce a proximal occlusion to prevent the reflux of liquid embolic agent (LEA) injected through a more distal microcatheter, and can be used to treat arteriovenous malformations and dural arteriovenous fistulae. The liquid embolic Magic Glue (MG) (N-hexyl cyanoacrylate (NHCA)) has been introduced as an alternative to N-butyl cyanoacrylate (NBCA). Our goals were to compare the extent of embolization of rete mirabile with or without the PC technique using NBCA or MG, and to compare the proximal occlusions obtained with MG or NBCA while using the PC technique in a renal arterial model.

METHODS

Rete mirabile were embolized with (n = 4) and without (n = 4) the PC technique, using MG (n = 4) or NBCA (n = 4). A renal arterial model was then used to study the characteristics of the MG plug (n = 10) used for the PC technique, and resistance to catheter withdrawal as compared to NBCA (n = 4). Specimens were analyzed macro- and microscopically and compared to angiographic results.

RESULTS

Extent of rete embolization with CYA agents was not significantly greater when using the PC technique. Results were similar with both types of cyanoacrylate (p = 0.657). The force necessary to withdraw the microcatheter was less with MG than with NBCA (p = 0.035).

CONCLUSION

MG was similar to NBCA in extent of rete embolization. Less traction force was necessary to withdraw trapped non-detachable microcatheters using MG compared to NBCA.

The transvenous retrograde pressure cooker technique for the curative embolization of high-grade brain arteriovenous malformations

BACKGROUND

Transvenous embolization of brain arteriovenous malformations (AVMs) can be curative. We aimed to evaluate the cure rate and safety of the transvenous retrograde pressure cooker technique (RPCT) using coils and n-butyl-2-cyanoacrylate as a venous plug.

METHODS

All AVM patients treated via transvenous embolization between December 2004 and February 2017 in a single center were extracted from our database. Inclusion criteria were: inability to achieve transarterial cure alone; AVM < 3 cm; and single main draining vein. Outcome measures were immediate and 90 days' angiographic AVM occlusion rate, and morbidity and mortality at 30 days and 12 months, according to the modified Rankin Scale (mRS) score.

RESULTS

Fifty-one patients (20 women; median age 47 years) were included. A majority (71%) were high grade (3 to 5 in the Spetzler-Martin classification). AVMs were deeply seated in 30 (59%) and cortical in 21 patients (41%). Thirty-three patients were previously embolized transarterially (65%). All patients but one were cured within a single session with the RPCT (96%). Cure was confirmed on follow-up digital subtraction angiography at 3 months in 82% of patients. Three patients experienced intracranial hemorrhage (6%), one requiring surgical evacuation. There were no deaths. One treatment-related major permanent deficit was observed (2.0%). Mean mRS before treatment, at 30 days, and 12 months after RPCT was 1.5, 1.5, and 1.3, respectively.

CONCLUSIONS

The retrograde pressure cooker technique can be curative in carefully selected high-grade AVMs. Long-term follow-up and prospective studies are needed to confirm our results.

N-Butyl Cyanoacrylate Transvenous Arteriovenous Malformation Embolization with Arterial Balloon Assistance: Defining Parameters for a Transvenous Approach as a Potential Upfront Treatment Option in Managing Cerebral Arteriovenous Malformations

Complete obliteration of arteriovenous malformations (AVMs) using a transvenous approach as the primary and stand-alone treatment modality has been increasingly considered as a useful endovascular approach in the treatment of AVMs. AVMs are typically treated with microsurgery, stereotactic radiosurgery, endovascular embolization, or some combination of the three methods. Preservation of the draining vein is a key requisite common to all treatment modalities. Transvenous embolization (TVE) is conventionally not recommended as a stand-alone treatment for the vast majority of AVMs and has been thought to be best indicated when traditional approaches are considered less safe and when specific evaluation criteria are met. We report a case of a 35-year-old asymptomatic male diagnosed with a small intracranial AVM adjacent to the right motor strip which was managed utilizing this approach. We employed endovascular embolization via a transvenous approach with arterial balloon assistance due to the small size of the nidus, eloquent location, en passage arterial supply proximal to the venous varix, and a single draining vein from the fistula. This case illustrates the selective indications and technical nuances of TVE approach in managing AVMs as a potential upfront treatment option. When patients harbor AVMs with specific angio-architectural findings as outlined, TVE utilizing Onyx or N-butyl cyanoacrylate can be safely performed as a primary treatment modality.

Facial Nerve Arterial Arcade Supply in Dural Arteriovenous Fistulas: Anatomy and Treatment Strategies

BACKGROUND AND PURPOSE

Endovascular treatment of petrous dural AVFs may carry a risk of iatrogenic facial nerve palsy if the facial nerve arterial arcade, an anastomotic arterial arch that supplies the geniculate ganglion, is not respected or recognized. Our purpose was to demonstrate that the use of a treatment strategy algorithm incorporating detailed angiographic anatomic assessment allows identification of the facial nerve arterial arcade and therefore safe endovascular treatment.

MATERIALS AND METHODS

This was a retrospective cohort study of consecutive petrous dural AVF cases managed at Toronto Western Hospital between 2006 and 2018. Our standard of care consists of detailed angiographic assessment followed by multidisciplinary discussion on management. Arterial supply, primary and secondary treatments undertaken, angiographic outcomes, and clinical outcomes were assessed by 2 independent fellowship-trained interventional neuroradiologists.

RESULTS

Fifteen patients had 15 fistulas localized over the petrous temporal bone. Fistulas in all 15 patients had direct cortical venous drainage and received at least partial supply from the facial nerve arterial arcade. Following multidisciplinary evaluation, treatment was performed by endovascular embolization in 8 patients (53%) and microsurgical disconnection in 7 patients (47%). All patients had long-term angiographic cure, and none developed iatrogenic facial nerve palsy.

CONCLUSIONS

By means of our treatment strategy based on detailed angiographic assessment and multidisciplinary discussion, approximately half of our patients with petrous AVFs were cured by endovascular treatment, half were cured by an operation, and all had preserved facial nerve function.

Safety and Efficacy of Transvenous Embolization of Ruptured Brain Arteriovenous Malformations as a Last Resort: A Prospective Single-Arm Study

BACKGROUND AND PURPOSE

The efficacy and safety of transvenous embolization for brain arteriovenous malformations remains unclear, given the very limited number of cases reported. This prospective study was performed to assess this technique in ruptured AVMs.

MATERIALS AND METHODS

Twenty-one consecutive patients with ruptured brain AVMs who underwent transvenous embolization were prospectively followed between November 2016 and November 2018. The Spetzler-Martin grade was I in 3 AVMs (14.3%), II in four (19.0%), III in eleven (52.4%), and IV in three (14.3%). The complete AVM occlusion rate was calculated from 6-month follow-up DSA images. Occurrence of hemorrhage and infarction after embolization was evaluated using CT and MR imaging within 1 month after the operation. The mRS was used to assess the functional outcomes.

RESULTS

Complete AVM nidus obliteration was shown in 16 (84%) of 19 patients with technically feasible AVMs immediately after embolization. One (5%) patient with a small residual nidus after treatment showed complete obliteration at 13-month follow-up. There were 5 hemorrhages and 1 infarction; 4 patients' symptoms improved gradually. The percentage of cases with mRS ≤ 2 rose from 57.1% (12/21) before embolization to 66.7% (14/21) at 1-month follow-up. Both the morbidity and mortality rates were 4.8% (1/21).

CONCLUSIONS

Transvenous embolization can be performed only in highly selected hemorrhagic brain AVMs with high complete obliteration rates, improved functional outcomes, and acceptable morbidity and mortality rates, but it should not be considered as a first-line treatment.

Endovascular transvenous treatment for superficial intracranial arteriovenous malformations

Objective

The objective of this study was to evaluate the feasibility and outcomes of transvenous endovascular embolization (TVE) for superficial intracranial arteriovenous malformations (AVMs).

Methods

After collecting clinical and imaging data, a prospective series of 11 patients presenting with superficial AVMs were treated by endovascular embolization using a transvenous approach between November 2016 and October 2018.

Results

Ten patients (90.9%) had ruptured AVMs before TVE. The mean nidus size was 3.27 ± 1.47 cm, and the median Spetzler-Martin grade was II. The rate of immediate angiographic occlusion of the AVMs was 90.9% (10/11). One patient was treated with transarterial embolization since TVE was not achieved due to an unsuccessful positioning of the microcatheter. Two patients (cases 8 and 11) suffered a intracranial hemorrhage and a cerebral infarction with encephaledema, respectively, but no procedure-related mortalities were observed. Eight patients (72.7%) were independent with a modified Rankin Score (mRS) ≤ 2 at discharge and the mRSs of all patients, which were collected 30 days postintervention, were not more than 2. The mean follow-up period was 17 months. There were no nidus recurrences during the follow-up period.

Conclusions

The curative transvenous embolization of superficial AVMs seems feasible and effective while carefully monitoring for embolization-related complications.

Transvenous Approach for the Treatment of cerebral Arteriovenous Malformations (TATAM): Study protocol of a randomised controlled trial

BACKGROUND

Transvenous embolisation is a promising technique but the benefits remain uncertain. We hypothesised that transvenous embolisation leads to a higher rate of arteriovenous malformation angiographic occlusion than transarterial embolisation.

METHODS

The Transvenous Approach for the Treatment of cerebral Arteriovenous Malformations (TATAM) is an investigator initiated, multicentre, prospective, phase 2, randomised controlled clinical trial. To test the hypothesis that transvenous embolisation is superior to transarterial embolisation for arteriovenous malformation obliteration, 76 patients with arteriovenous malformations considered curable by up to two sessions of endovascular therapy will be randomly allocated 1:1 to treatment with either transvenous embolisation (with or without transarterial embolisation) (experimental arm) or transarterial embolisation alone (control arm). The primary endpoint of the trial is complete arteriovenous malformation occlusion, assessed by catheter cerebral angiography. Complete occlusions will be confirmed at 3 months, while incompletely occluded arteriovenous malformations, considered treatment failures, will then be eligible for complementary treatments by surgery, radiation therapy, or even transvenous embolisation. Standard procedural safety outcomes will also be assessed. Patient selection will be validated by a case selection committee, and participating centres with limited experience in transvenous embolisation will be proctored.

DISCUSSION

The TATAM trial is a transparent research framework designed to offer a promising but still unvalidated treatment to selected arteriovenous malformation patients. Clinical Trial Registration-URL: http://www.clinicaltrials.gov . Unique identifier: NCT03691870.

Embolizing intracranial arteriovenous malformations with Onyx: experience at a single center with 250 patients

Objective The aim of this study is to evaluate the embolization techniques, as well as the effects and complications, using the non-adhesive liquid embolic material Onyx in intracranial arteriovenous malformations (AVMs). Methods The study comprises a retrospective analysis of 250 patients with intracranial AVMs treated with Onyx in Guangdong General Hospital from Jan 2010 to Dec 2017. The therapeutic strategies, as well as embolization effects and complications, of Onyx are summarized. Results Of 250 cases, 170 were male and 80 were female. Following the Spetzler-Martin (S-M) grading system, there were 35 cases of grade I, 77 of grade II, 72 of grade III, 39 of grade IV, and 27 of grade V. All cases were treated with Onyx. In addition, 69 cases were treated with Glubran glue. The injected volume of Onyx per patient ranged from 1 mL to 10 mL. The largest volume of Onyx injected in one procedure was 10 mL. The cure rate was 67.9% (76/112) of grade I-II patients, 15.0% (11/72) of grade III patients, 7.7% (3/39) of grade IV patients, and 0% (0/27) of grade V patients. The total cure rate was 36.0% (90/250). The average number of targeted vascular branches per patient was 2.28. The microcatheter broke off in two cases. There were two patients who suffered an intracranial hemorrhage during the embolic procedure; in one of these two patients, the microcatheter also broke off. There were two patients who suffered an intracranial hemorrhage after the embolic procedure; one of them died. Seven cases suffered new-onset neurological deficits or their original symptoms deteriorated. Six of them improved or recovered within 3-6 months. The total complication rate was 5.2% (13/250). Conclusion The application of Onyx in intracranial AVMs is flexible, effective and safe, and may also reduce the complications.

Surgical management of complex brain arteriovenous malformations with hybrid operating technique: study protocol of a prospective registry and a pragmatic clinical trial

BACKGROUND

Complex brain arteriovenous malformations (bAVMs) in ≥3 Spetzler-Martin grades have long been challenges among cerebrovascular diseases. None of the traditional methods, such as microsurgical operation, endovascular intervention, or stereotactic radiotherapy, can completely eliminate complex bAVMs without a risk of neural function deterioration. The multistaged hybrid operation solved part of the challenge but remained risky in the installment procedures and intervals. The one-staged hybrid operation was applied in the surgical treatment of cerebrovascular diseases and proved to be a potentially safe and effective method for curing complex bAVMs. However, lacking the support of high-level evidence, its advantages remain unclear. This study was proposed to validate the benefits and risks of one-staged hybrid operation in the treatment of complex bAVMs, as well as its indications, key technologies, and workflows.

METHODS

The study is being conducted from Jan 2016 to Dec 2020 with 20 cooperation centers. It consists of 2 sets. The registry set is designed as a prospective real-world registry. The trial set is designed as a prospective pragmatic clinical trial, specifically for the patients with perforating arterial feeders. The two sets share a common grouping: the traditional operation group and the one-staged hybrid operation group. The assignment is based on the clinical condition in the registry set and is randomized in the trial set. End points will be evaluated at scheduled time points. The safety and efficiency of one-staged hybrid operation in treating complex bAVMs will be validated.

DISCUSSION

The study is designed for a real-world exploration of benefits and risks of one-staged hybrid operation in the treatment of complex bAVMs. The two-set design reduces the compromise of clinical practice due to the study and improves the statistical power and research quality with a practical sample size. In the study, advantages of the one-staged hybrid operation will be evaluated and compared to those of traditional operation. A spanning development of neurosurgical operation might be facilitated by the study, which means a higher cure rate and lower disability rate in patients with complex bAVMs.

TRIAL REGISTRATION

The study was retrospectively registered in ClinicalTrials.gov ( NCT03774017 ) on 11th Dec, 2018.

Current status of endovascular treatment for dural arteriovenous fistula of the transverse-sigmoid sinus: A literature review

Most intracranial dural arteriovenous fistulae (DAVFs) involve the transverse-sigmoid sinus (TSS), and various types of endovascular treatment (EVT) have been involved in managing TSS DAVFs. A current, comprehensive review of the EVT of TSS DAVFs is lacking. This study used the PubMed database to perform a literature review on TSS DAVFs to increase the current understanding of this condition. For high-grade TSS DAVFs such as Borden type 3, the goal of EVT is curative treatment. However, for low-grade TSS DAVFs such as Borden type 1 and some Borden type 2 TSS DAVFs, symptom relief or elimination of cortical reflux may be sufficient. Currently, EVT has become the first-line treatment for TSS DAVFs, including transarterial embolization (TAE), transvenous embolization (TVE) or both. TAE alone and TSS balloon-assisted TAE are also commonly used. However, TVE for TSS DAVFs is recognized as the most effective treatment, including coil direct packing TSS, Onyx® (ethylene vinyl alcohol copolymer) TVE, and balloon-assisted Onyx® TVE, which are commonly applied. In addition, TSS reconstructive treatment can be an effective procedure to treat TSS DAVFs. EVT is accompanied with complications, including technique- and treatment-related complications. Although complications may occur, TSS DAVFs have an acceptable prognosis after EVT.

Transvenous embolization of arteriovenous malformations

Embolization of arteriovenous malformations is characteristically used as part of a multimodal treatment approach, pre-operatively to facilitate microsurgical resection or as a preradiosurgical adjunct. The concept of AVM cure via embolization alone has gained popularity in recent years. Embolization of AVMs has been most commonly performed transarterially, with the transvenous route traditionally eschewed given concern over precipitating premature venous occlusion and consequent hemorrhage. However, the transvenous approach in treating AVMs offers several distinct advantages compared to the transarterial route and can be used in instances when the latter is not feasible, with several series having proven its efficacy and safety. Conceptually, AVM embolization performed via the transvenous route achieves complete obliteration by directly and facilely targeting the nidus. Nidal embolisate penetration is facilitated by control of arterial inflow via systemic or local hypotension. Innovation in endovascular strategies has led to significantly improved obliteration rates. The experience with transvenous AVM embolization is reviewed and discussed.

High-Grade Dural Arteriovenous Fistulas : Use of Kaneka ED Coils with the Marathon Microcatheter for Transvenous Coil Embolization

BACKGROUND

Dural arteriovenous fistulas (DAVF) are commonly encountered lesions that can be treated both transvenously, transarterially or using a combined approach.

OBJECTIVE

Transvenous coil embolization of DAVF is a recognized treatment option but can be challenging. In this context this article presents clinical experience using the Kaneka ED10 ExtraSoft coils in combination with the Marathon microcatheter to treat high grade DAVF. The physical properties of these coils and the microcatheter were also determined.

MATERIAL AND METHODS

All patients with high grade DAVF treated with the Marathon and the Kaneka ED COIL ∞10 ExtraSoft coils were retrospectively identified. The clinical presentation, location, grade of the lesion, clinical and radiological follow-up data were recorded. Bench side studies were performed to determine the physical properties of the Marathon catheter in comparison to the SL10 and Headway Duo as well the maximum width of the Kaneka pusher wire in comparison to Hypersoft, Target and Axium Prime coils.

RESULTS

A total of 8 patients with 9 DAVF with 3 Cognard 3 and 6 Cognard 4 lesions were identified. All the DAVF's were occluded either at the end of the procedure or on follow-up imaging. On bench side tests the Marathon microcatheter had the most flexible distal tip and distal shaft in comparison to the SL10 and Headway Duo. The proximal shaft of the Marathon was stiffer than the SL10. The Kaneka ED COIL ∞10 ExtraSoft had the smallest distal width and were the only coils tested that could be deployed through a Marathon microcatheter.

CONCLUSION

The combination of the Marathon microcatheter and Kaneka ED COIL ∞10 ExtraSoft is useful for the treatment of high grade DAVF.

Transvenous embolization of brain arteriovenous malformations: a review of techniques, indications, and outcomes

Endovascular embolization of brain arteriovenous malformations (AVMs) is conventionally performed from a transarterial approach. Transarterial AVM embolization can be a standalone treatment or, more commonly, used as a neoadjuvant therapy prior to microsurgery or stereotactic radiosurgery. In contrast to the transarterial approach, curative embolization of AVMs may be more readily achieved from a transvenous approach. Transvenous embolization is considered a salvage therapy in contemporary AVM management. Proposed indications for this approach include a small (diameter < 3 cm) and compact AVM nidus, deep AVM location, hemorrhagic presentation, single draining vein, lack of an accessible arterial pedicle, exclusive arterial supply by perforators, and en passage feeding arteries. Available studies of transvenous AVM embolization in the literature have reported high complete obliteration rates, with reasonably low complication rates. However, evaluating the efficacy and safety of this approach is challenging due to the limited number of published cases. In this review the authors describe the technical considerations, indications, and outcomes of transvenous AVM embolization.

Curative Transvenous Embolization for Ruptured Brain Arteriovenous Malformations: A Single-Center Experience from China

OBJECTIVE

To evaluate feasibility and safety of transvenous embolization for brain arteriovenous malformations (AVMs).

METHODS

Between November 2016 and August 2017, a transvenous endovascular embolization protocol was implemented at the Henan Provincial People's Hospital for consecutive patients with ruptured brain AVMs. Therapeutic decision making was based on Spetzler-Martin grade, brain AVM location, pattern of venous drainage, and angioarchitecture. Transvenous embolization was combined with transarterial support. Complete angiographic obliteration of the nidus was the objective of treatment.

RESULTS

Among 10 patients with ruptured brain AVMs, 8 were male. Spetzler-Martin grades before transvenous embolization were IV in 3 patients, III in 5 patients, II in 1 patient, and I in 1 patient. Modified Rankin Scale score before the procedure was 0-2 for 6 of 10 patients. Five patients also had deep venous drainage. Arterial blood pressure control and venous pressure cooker technique were used in all 10 patients; 9 patients had immediate angiographic occlusion. Two patients had a ventricular hemorrhage, which did not cause any disability after medical treatment. Seven patients underwent angiography 3-5 months after the procedure, and complete obliteration of the nidus was confirmed. Median clinical follow-up for all 10 patients was 8 months (range, 3-12 months). Epilepsy occurred in 1 patient 3 months after the procedure, and modified Rankin Scale scores for all patients were ≤1.

CONCLUSIONS

Transvenous embolization of brain AVMs is feasible and may improve cure rates. The safety and long-term effects need further validation.

Transvenous retrograde AVM embolization: Indications, techniques, complications and outcomes

Objective Transvenous retrograde arteriovenous malformation (AVM) embolization (TRAE) has been proposed. The present study was to review the techniques, their conjunctions and effectiveness. Methods Eligible related articles were identified by searching the PubMed and Web of Science databases using "transvenous" and "arteriovenous malformation." Results A total of 16 eligible studies, with 60 cases of AVM treated with TRAE, were analyzed. Prior to TRAE procedure, transarterial Onyx 18 was performed in 23 (38.3%), cyanoacrylate in three (5%) and coiling in two (3.3%), neurosurgery in one (1.7%) and radiosurgery in three (5%). These prior treatments were used to reduce the size of the nidus to <3 cm and TRAE was performed. One anterior choroidal artery aneurysm was coiled before TRAE. Systemic hypotension (blood pressure<100 mmHg) occurred in six (10%) patients and local hypotension (proximal arterial temporary balloon protection) in five (8.3%) patients. Complete obliteration was achieved in 56 (93.3%) AVMs, four (6.7%) with residual, of which one was supplemented with radiosurgery. During mean one-year follow-up (1 month to 3.2 years), there were five cases (8.3%) of permanent disability and one (1.7%) mortality resulting from initial hemorrhage. Fifty-four (90%) patients were independent (mRS ≤ 2) at follow-up. Ruptured AVMs and Spetzler-Martin I-III were associated with a high cure rate. Conclusion According to previous reports, selected AVMs could undergo TRAE. TRAE is safe and curative with Onyx after the nidus size is reduced sufficiently by transarterial embolization, neurosurgery or radiosurgery, with or without the aid of proximal arterial temporary balloon protection.

Curative and adjunctive AVM Onyx embolization of AVMs through the choroidal arteries

Objective The anterior or posterior choroidal artery is often recruited to supply deep location arteriovenous malformations (AVMs). This study is to report curative and adjunctive AVM Onyx embolization through these arteries. Methods This study retrospectively reviewed six patients with cerebral AVMs who underwent endovascular embolization through the choroidal arteries between October 2015 and October 2016. Embolization was performed as a curative procedure in five patients and adjunctive procedure in one patient. Results Four patients underwent embolization through the anterior choroidal artery (AchA), and two patients underwent embolization through the lateral posterior choroidal artery (LPchA). One of the four patients in whom embolization was from the AchA (distal to the plexal point) developed transient hemiparesis. Complete obliteration was confirmed by angiography at the last follow-up in five patients. Conclusions Onyx embolization of cerebral AVMs through the choroidal arteries is possible as a curative or adjunctive procedure.

Extending the indications for transvenous approach embolization for superficial brain arteriovenous malformations

INTRODUCTION

Transarterial embolization is the standard endovascular treatment strategy for intracranial arteriovenous malformations (AVMs). The transvenous approach has been indicated for the embolization of deep AVMs meeting a set of strict eligibility criteria. The present study aims to assess the safety and efficacy of the transvenous approach for superficial AVMs.

METHODS

A retrospective series of 12 patients presenting with cortical AVMs were treated by endovascular embolization using a transvenous approach with a curative intent.

RESULTS

Nine patients (75%) had ruptured AVMs at admission. The mean nidus size was 1.9 cm, six patients (50%) had a nidus in eloquent areas and the median Spetzler-Martin grade was 2. The rate of immediate angiographic occlusion of the AVMs was 91.6% (11/12). One patient in whom immediate angiographic occlusion was not achieved showed spontaneous occlusion at the 6-month follow-up. No procedural or clinical complications were observed. The mean and median modified Rankin scale (mRS) scores at discharge were 1.7 and 2 (range 0-3, SD=0.96), and the mean and median mRS scores at 6 months were 1.6 and 2 (0-3, 1.16). Nine patients (75%) were independent (mRS ≤2) at discharge and 11 patients (91.6%) were independent (mRS ≤2) at the 6-month follow-up.

CONCLUSIONS

The curative transvenous embolization of superficial intracranial AVMs is feasible and appears safe and effective when strict anatomical selection is respected. This technique extends the current indications for transvenous embolization of intracranial AVMs and may improve cure rates while reducing embolization-related complications.