Onyx versus other liquid embolicagents for AVM treatment

LINC 2020, Leipzig, GermanyWalter A. Wohlgemuth

University Clinic and Policlinic of RadiologyMartin-Luther Universität Halle-Wittenberg, Germany

Conflicts of interest

Scientific grants:Siemens, Phillips, ab medica, ev3/covidien/medtronic, itm, Toshiba, Cook, W. L. Gore, Bracco

Lectures: ev3/covidien/medtronic, Biotronic, St Jude Medical, Abbott, Siemens, ab medica, Boston Scientific, itm Flowmedical, Terumo, W. L. Gore, IGEA

Consulting:1st WITiG, itm Flowmedical, Siemens, ev3/covidien/medtronic, ab medica

Embolisation agents

• Gelfoam• Embozene• DSM• PVA

Amplatzer VascularPlugsMicro Vascular Plugs

• Ethanol (-gel)• NBCA • EVOH

• Pushable Coils• Detachable Coils

ParticlesPlugs Liquid agentsCoils

Vessel diameter

Particles

Liquid embolic agents

Plugs

Microplugs

Coils

Microcoils

Embolic agents

Liquid embolic agents

Sclerosing Agents Glue Polymer EVOH

N-butyl-2-cyanoacrylate (n-BCA)

+

CAVE: Glued microcatheter → preflush glucose solution

Drawbacks• Flow and polymerisation time of N-butyl-2-cyanoacrylate are hard

to predict and sometimes quick– Passive distribution along the flow direction -> control?– Incomplete embolisation versus non-target embolisation

in veins / lung

• As close as possible to target– No active pushing of the agent

• Use requires experience and skills– Otherwise microcatheter gets stuck (detachable-tip microcatheter

may be a solution)

• „Inject and pull“ approach– Recanulation of vessel necessary

α-hexyl-cyanoacrylate (Magic glue)

• Slower polymerisation speed

• More “elastic” cast

• Less adhesive to microcatheter

• Remains liquid until it comes in contact with tissue

Chain of 6 carbons -> hexyl

α-hexyl-cyanoacrylate (Magic glue)

Only pre Clinical Study:

• This new glue has the same occlusive efficacy in short and long term than n-butyl-2-cyanoacrylate

• Adhesion strength of hexyl-cyanoacrylate to catheterwas less important than that of n-butyl-2-cyanoacrylate

• CE mark in 2018

Preclinical study on an animal model of a new non-adhesive cyanoacrylate (Purefill®) for arterial embolization - J. Izaaryene & al - Diagnostic and Interventional Imaging (2016) 97, 1109 – 1116 - http://dx.doi.org/10.1016/j.diii.2016.05.013

Indications for cyanoacrylates

• Acute bleeding

• Preoperative tumor embolisation

• Neuroradiology: spinal AVM, (cer AVM)

• Portal vein embolisation

• Thoracic duct embolisation

• Various other indications

Ethylene Vinyl Alcohol Copolymer (EVOH)

• Plastic: liquid monomer → solid polymer – Onyx (18, 34)L, Squid (12,18,34)L, (PHIL)

• Slow polymerisation (diffusion of solvent DMSO)– Controlled process, central core remains liquid

– Longer procedure time, higher radiation dose

• Used material has to be DMSO compatible

• Radioopaque (micronized Tantalum / Iodine)

• Expansive

• Very controllable + effective, but…– Local complications: pain, ischemia, necrosis

– Systemic complications: Upper dose of DMSO 0.583 ml/kg bodyweight

EVOH: Unique properties

• Active distribution even against blood stream possible

– As opposed to passive, flow-related distribution(NBCA, alcohol)

– Retrograde injection: from transvenous to arterial

• „plug & push technique“

• CM-injection in DSA is flow-passive as well……

– DSA-images of AVM may not display the complete angio-anatomy, flow changes during embolisation

– AVM nidus is larger than visualised in DSA

Indications for EVOH

• Neuroradiology: AVM, V. Galen aneurysm, dAVF

• Acute bleeding

• Endoleak embolization after EVAR (type II, type I)

• Arteriovenous malformations (body)

• (Preoperative tumor embolisation)

• (bile leakage)

• Various other indications

Univ.-Prof. Dr. Dr. Walter A. WohlgemuthUniversity Clinic and Policlinic of Radiology

Martin-Luther University Halle-Wittenberg, Germany

Thank you for your attention

Onyx versus other liquid embolicagents for AVM treatment

LINC 2020, Leipzig, GermanyWalter A. Wohlgemuth

University Clinic and Policlinic of RadiologyMartin-Luther Universität Halle-Wittenberg, Germany