Emerging embolic agents in endovascular embolization: an overview

Object Spinal dural arteriovenous fistulas (DAVFs) are the most common spinal vascular malformations and can be a significant cause of myelopathy, yet remain inefficiently diagnosed lesions. Over the last several decades, the treatment of spinal DAVFs has improved tremendously due to improvements in neuroimaging, microsurgical, and endovascular techniques. The aim of this paper was to review the existing literature regarding the clinical characteristics, classification, and endovascular management of spinal DAVFs. Methods A search of the PubMed database from the National Library of Medicine and reference lists of all relevant articles was conducted to identify all studies pertaining to spinal DAVFs, spinal dural fistulas, and spinal vascular malformations, with particular attention to endovascular management and outcomes. Results The ability to definitively treat spinal DAVFs using endovascular embolization has significantly improved over the last several decades. Overall rates of definitive embolization of spinal DAVFs have ranged between 25 and 100%, depending in part on the embolic agent used and the use of variable stiffness microcatheters. The majority of recent studies in which N-butyl cyanoacrylate or other liquid embolic agents were used have reported success rates of 70–90%. Surgical treatment remains the definitive option in cases of failed embolization, repeated recanalization, or lesions not amenable to embolization. Clinical outcomes have been comparable to surgical treatment when the fistula and draining vein remain persistently occluded. Improvements in gait and motor function are more likely following successful treatment, whereas micturition symptoms are less likely to improve. Conclusions Endovascular embolization is an increasingly effective therapy in the treatment of spinal DAVFs, and can be used as a definitive intervention in the majority of patients that undergo modern endovascular intervention. A multidisciplinary approach to the treatment of these lesions is required, as surgery is required for refractory cases or those not amenable to embolization. Newer embolic agents, such as Onyx, hold significant promise for future therapy, yet long-term follow-up studies are required.

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

The Neuroradiology Journal ◽

10.1177/19714009211047453 ◽

2021 ◽

pp. 197140092110474

Author(s):

Muhammad H Malik ◽

Waleed Brinjikji ◽

Luis E Savastano

Keyword(s):

Arteriovenous Fistula ◽

Side Effect ◽

Dural Arteriovenous Fistula ◽

Endovascular Embolization ◽

Embolic Agents ◽

Liquid Embolic

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.

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Removal of distal fragments of liquid embolic agents during arteriovenous malformation embolization using the TIGERTRIEVER 13: a technical report

Journal of NeuroInterventional Surgery ◽

10.1136/neurintsurg-2019-015474 ◽

2020 ◽

Vol 12 (8) ◽

pp. 794-797 ◽

Cited By ~ 1

Author(s):

Faith LY Ho ◽

René Chapot

Keyword(s):

Cerebral Artery ◽

Endovascular Embolization ◽

Neurological Deficits ◽

Vascular Lesions ◽

Embolic Agent ◽

Embolic Material ◽

Embolic Agents ◽

Liquid Embolic ◽

Retrograde Filling ◽

Distal Migration

BackgroundArteriovenous malformations (AVMs) are vascular lesions that may be treated by an endovascular approach using liquid embolic agents but the control of the liquid embolic agent remains poor and a potential complication may be distal migration of embolic material. The TIGERTRIEVER 13 is a new stent retriever designed for stroke thrombectomy and has a version ideal for distal occlusions. We report our experience in the removal of embolic agent which had migrated into the distal vessels using the TIGERTRIEVER during PHIL/Onyx embolization of AVMs.Clinical presentationsThree patients with brain and spinal AVMs underwent endovascular embolization. During trans-arterial embolization of the AVM with PHIL/Onyx, retrograde filling of distal arterial feeders was followed by migration into the normal arterial branches (cortical middle cerebral artery, distal posterior cerebral artery, and anterior spinal artery). This resulted in occlusion or sluggish distal flow in these branches with potential significant neurological deficits. In all three cases, a Headway Duo microcatheter was navigated distally in the occluded vessel beyond the embolic material using a Traxcess microwire. The TIGERTRIEVER 13 was deployed with recanalization of the vessel after a single attempt. In all three patients there were no complications related to the retrieval of embolic agent.ConclusionDistal migrated embolic agents such as PHIL or Onyx can be removed from various arterial vascular territories using stent retrievers dedicated to small vessels.

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Evaluation of a novel liquid embolic agent (precipitating hydrophobic injectable liquid (PHIL)) in an animal endovascular embolization model

Journal of NeuroInterventional Surgery ◽

10.1136/neurintsurg-2017-013144 ◽

2017 ◽

Vol 10 (3) ◽

pp. 268-274 ◽

Cited By ~ 15

Author(s):

Dominik F Vollherbst ◽

Ruth Otto ◽

Andreas von Deimling ◽

Johannes Pfaff ◽

Christian Ulfert ◽

...

Keyword(s):

Waiting Time ◽

Transarterial Embolization ◽

Endovascular Embolization ◽

Embolic Agent ◽

Rete Mirabile ◽

Embolic Agents ◽

Liquid Embolic ◽

Liquid Embolic Agent ◽

Group Survival

BackgroundThe choice of the embolic agent and the embolization technique can have a significant impact on the success of endovascular embolization.ObjectiveTo evaluate a novel iodinated copolymer-based liquid embolic agent (precipitating hydrophobic injectable liquid (PHIL)) in the porcine rete mirabile (RM), serving as an endovascular embolization model. Onyx, as an established liquid embolic agent, served as comparator.Materials and methodsSixteen embolization procedures were performed using PHIL (n=8) or Onyx (n=8) as liquid embolic agent. Waiting time between injections was set to 30 or 60 s (n=4 per study group). Survival time after intervention was 2 hours or 7 days. Embolization characteristics (eg, procedure times, number of injections and volume of embolic agent) and embolization extent (percentage of embolized RM in post-interventional x-ray) were assessed. Post-interventional CT and histopathological analyses were performed.ResultsEmbolization characteristics and embolization extent were not significantly different for PHIL and Onyx, including subgroups (eg, embolization extent 44% vs 69% (medians); p=0.101). For PHIL, extension of the waiting time from 30 to 60 s led to a significantly higher embolization extent (24% vs 72% (medians); p=0.035). Moderate disintegration and mild inflammation of the embolized blood vessels were present for both embolic agents.ConclusionPHIL is feasible for transarterial embolization in an acute and subacute endovascular embolization model. In this preliminary experimental in vivo study, embolization characteristics, embolization extent, and biocompatibility seem to be similar to those of Onyx.

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Neurological outcomes and cure rates of embolization of brain arteriovenous malformations with n-butyl cyanoacrylate or Onyx: a meta-analysis

Journal of NeuroInterventional Surgery ◽

10.1136/neurintsurg-2014-011427 ◽

2014 ◽

Vol 8 (3) ◽

pp. 265-272 ◽

Cited By ~ 34

Author(s):

Abdussalam Elsenousi ◽

Victor A Aletich ◽

Ali Alaraj

Keyword(s):

Arteriovenous Malformations ◽

Meta Analysis ◽

Endovascular Embolization ◽

Complication Rates ◽

Cure Rate ◽

Ethylene Vinyl Alcohol ◽

Neurological Outcomes ◽

Embolic Agents ◽

Liquid Embolic ◽

Cure Rates

BackgroundIn the past decade, preoperative endovascular embolization of cerebral arteriovenous malformations (AVMs) became an essential tool in the treatment of these entities. With the current expansion of technology and wide incorporation of new devices, the indications for the use of endovascular embolization have expanded to include embolization for cure. This has been facilitated by the wide use of the new liquid embolic agents (ethylene-vinyl alcohol co-polymer (EVOH)) in addition to n-butyl cyanoacrylate (NBCA). The aim of this study was to review the current published literature for these two agents and report on permanent neurological injuries and cure rate.MethodsPublished literature citing embolization results for AVMs using liquid embolic agents was reviewed. Papers reporting on permanent complication rates and complete angiographic cure were reviewed. A meta-analysis was performed based on these two variables for the two embolic agents.Results103 studies met the selection criteria. Poor neurological outcomes for NBCA and EVOH were 5.2% and 6.8%, respectively (OR 1.4; p=0.56). AVM complete obliteration rate was seen in 13.7% in the NBCA group and in 24% in the EVOH group (OR 1.9). This OR decreased to 1.35 in the subgroup analysis for patients treated after the year 2000.ConclusionsNBCA continues to have a trend towards lower permanent complication rates, but EVOH had higher angiographic cure rates. The recent literature has demonstrated an increase in the cure rate of AVMs with endovascular embolization techniques yet with a possible increase in permanent neurological deficits and mortality.

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Liquid Embolic Agents for Endovascular Embolization: Evaluation of an Established (Onyx) and a Novel (PHIL) Embolic Agent in an In Vitro AVM Model

American Journal of Neuroradiology ◽

10.3174/ajnr.a5203 ◽

2017 ◽

Vol 38 (7) ◽

pp. 1377-1382 ◽

Cited By ~ 19

Author(s):

D.F. Vollherbst ◽

C.M. Sommer ◽

C. Ulfert ◽

J. Pfaff ◽

M. Bendszus ◽

...

Keyword(s):

Endovascular Embolization ◽

Embolic Agent ◽

Embolic Agents ◽

Liquid Embolic

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Liquid and Solid Embolic Agents in Gonadal Veins

Journal of Clinical Medicine ◽

10.3390/jcm10081596 ◽

2021 ◽

Vol 10 (8) ◽

pp. 1596

Author(s):

Francesco Tiralongo ◽

Giulio Distefano ◽

Monica Palermo ◽

Antonio Granata ◽

Francesco Giurazza ◽

...

Keyword(s):

Recurrence Rate ◽

Relevant Literature ◽

Young Patients ◽

Endovascular Embolization ◽

Interventional Treatment ◽

Embolic Agents ◽

Meta Analyses ◽

Almost All ◽

Pelvic Congestion

Male varicocele and pelvic congestion syndrome (PCS) are common pathologies with high predominance in young patients, having a high impact on the quality of life and infertility. Lately, the use of different endovascular embolization techniques, with various embolizing agents, shows good technical results and clinical outcomes. With the aim of presenting the “state of the art” of endovascular techniques for the treatment of male varicocele and PCS, and to discuss the performance of the different embolic agents proposed, we conducted an extensive analysis of the relevant literature and we reported and discussed the results of original studies and previous meta-analyses, providing an updated guide on this topic to clinicians and interventional radiologists. We have also underlined the technical aspects for the benefit of those who approach this type of interventional treatment. Our review suggests promising results in both the endovascular embolic treatment of male varicocele and PCS; for varicocele, a success rate of between 70% and 100% and a recurrence rate of up to 16% is reported, while for PCS it has been found that technical success is achieved in almost all cases of endovascular treatment, with a highly variable recurrence rate based on reports. Complications are overall rather rare and are represented by periprocedural pain, migration of embolic media and vascular perforations: severe adverse events have been reported very rarely.

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Curing arteriovenous malformations using embolization

Neurosurgical FOCUS ◽

10.3171/2014.6.focus14228 ◽

2014 ◽

Vol 37 (3) ◽

pp. E19 ◽

Cited By ~ 21

Author(s):

Matthew B. Potts ◽

Daniel W. Zumofen ◽

Eytan Raz ◽

Peter K. Nelson ◽

Howard A. Riina

Keyword(s):

Arteriovenous Malformations ◽

Endovascular Embolization ◽

Cerebral Arteriovenous Malformations ◽

Curative Intent ◽

The Past ◽

Embolic Agents ◽

Liquid Embolic ◽

Diagnostic Angiography ◽

Endovascular Technology

Endovascular embolization is typically reserved as an adjuvant therapy in the management of cerebral arteriovenous malformations (AVMs), either for preoperative devascularization or preradiosurgical volume reduction. Curative embolization plays a limited role in AVM treatment but several studies have shown that it is possible, especially with later-generation liquid embolic agents. Given the complexity of AVM anatomy and the recent controversies over the role of any intervention in AVM management, it is critical that the cerebrovascular community better define the indications of each treatment modality to provide quality AVM management. In this review, the authors evaluate the role of curative AVM embolization. Important considerations in the feasibility of curative AVM embolization include whether it can be performed reliably and safely, and whether it is a durable cure. Studies over the past 20 years have begun to define the anatomical factors that are amenable to complete endovascular occlusion, including size, feeding artery anatomy, AVM morphology, and endovascular accessibility. More recent studies have shown that highly selected patients with AVMs can be treated with curative intent, leading to occlusion rates as high as 100% of such prospectively identified lesions with minimal morbidity. Advances in endovascular technology and techniques that support the efficacy and safety of curative embolization are discussed, as is the importance of superselective diagnostic angiography. Finally, the durability of curative embolization is analyzed. Overall, while still unproven, endovascular embolization has the potential to be a safe, effective, and durable curative treatment for select AVMs, broadening the armamentarium with which one can treat this disease.

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Experience of intracranial arteriovenous malformations endovascular treatment with advanced techniques and non-adhesive liquid embolic agents using

Endovascular Neuroradiology ◽

10.26683/2304-9359-2020-3(33)-29-38 ◽

2020 ◽

Vol 33 (3) ◽

pp. 29-38

Author(s):

Yu.V. Cherednichenko ◽

L.A. Dzyak ◽

E.S. Tsurkalenko

Keyword(s):

Endovascular Treatment ◽

Arteriovenous Malformations ◽

Low Frequency ◽

Endovascular Embolization ◽

Average Decrease ◽

Embolic Agents ◽

Increased Risk ◽

Liquid Embolic ◽

Risk Of Rupture ◽

Clinically Significant

Objective ‒ to evaluate the possibility of endovascular embolization using non-adhesion of liquid embolic agents as monotherapy for the treatment of cerebral arteriovenous malformations (AVM), its reliability and safety.Materials and methods. examination and gradual endovascular treatment of 64 patients (120 sessions) using non-adhesive liquid embolic agents. Patients were divided into two groups: with ruptured AVM (n = 43) and with unruptured (n = 21). In all cases of unruptured AVM, signs indicating an increased risk of rupture of the AVM were verified.Results. the average decrease in volume after embolization was 79.5 % (up to 50 % ‒ in 7 cases, 50‒75 % ‒ in 14, 75‒99 % ‒ in 29). Complete exclusion of AVM was achieved in 14 (22 %) patients. On average, 2–3 feeders were embolized on the AVM to achieve such results. It was found that the number of feeders was directly proportional to the number of sessions required. Malformations of small size (up to 3 cm) often managed to close in one session. Clinically significant deficiency (2 on the modified Rankin scale) after embolization was found in 2 (3 %) patients. The deficit regressed within 7 days. The angiographic frequency of complete obliteration of AVM at the end of all embolization procedures was 22 % (14 AVM).Conclusions. knowledge of the angioarchitectural characteristics of AVM, which are suitable for the treatment with liquid embolic agents, and their careful selection allow to achieve a high frequency of occlusion with a low frequency of complications. The use of superselective intranidal or perinidal positions of the catheter, slow controlled injections that protect the draining veins, the gradual embolization make the therapy safer.

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Glue, Onyx, Squid or PHIL? Liquid Embolic Agents for the Embolization of Cerebral Arteriovenous Malformations and Dural Arteriovenous Fistulas

Clinical Neuroradiology ◽

10.1007/s00062-021-01066-6 ◽

2021 ◽

Author(s):

Dominik F. Vollherbst ◽

René Chapot ◽

Martin Bendszus ◽

Markus A. Möhlenbruch

Keyword(s):

Arteriovenous Malformations ◽

Vascular Malformations ◽

Endovascular Embolization ◽

Embolic Agent ◽

Cerebral Arteriovenous Malformations ◽

Arteriovenous Fistulas ◽

Advantages And Disadvantages ◽

Embolic Agents ◽

Liquid Embolic ◽

Dural Arteriovenous Fistulas

Abstract Background Endovascular embolization is an effective treatment option for cerebral arteriovenous malformations (AVMs) and dural arteriovenous fistulas (DAVFs). A variety of liquid embolic agents have been and are currently used for embolization of AVMs and DAVFs. Knowledge of the special properties of the agent which is used is crucial for an effective and safe embolization procedure. Material and Methods This article describes the properties and indications of the liquid embolic agents which are currently available: cyanoacrylates (also called glues), and the copolymers Onyx, Squid and PHIL, as well as their respective subtypes. Results Cyanoacrylates were the predominantly used agents in the 1980s and 1990s. They are currently still used in specific situations, for example for the occlusion of macro-shunts, for the pressure cooker technique or in cases in which microcatheters are used that are not compatible with dimethyl-sulfoxide. The first broadly used copolymer-based embolic agent Onyx benefits from a large amount of available experience and data, which demonstrated its safety and efficacy in the treatment of cerebral vascular malformations, while its drawbacks include temporary loss of visibility during longer injections and artifacts in cross-sectional imaging. The more recently introduced agents Squid and PHIL aim to overcome these shortcomings and to improve the success rate of endovascular embolization. Novelties of these newer agents with potential advantages include extra-low viscosity versions, more stable visibility, and a lower degree of imaging artifacts. Conclusion All the available liquid embolic agents feature specific potential advantages and disadvantages over each other. The choice of the most appropriate embolic agent must be made based on the specific material characteristics of the agent, related to the specific anatomical characteristics of the target pathology.

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