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EP- 104 EVALUATION OF VISUAL
CONTROL DURING FLUOROSCOPIC ONYX® (EVOH)
INJECTIONS USING A NOVEL CALIBRATED VASCULAR MODEL
James Ryan Mason, DO, MPH 1, Guyla Gal, MD2, Goetz Benndorf, MD, PhD 2
1 Swedish Medical Center, Seattle, Washington2 University of Southern Denmark, Odense
Disclosures:
JRM: None
GB: None
Gal: Consultant - Balt Extrusion
Consultant - Penumbra
Purpose:Onyx® is a well established non-adhesive liquid embolic agent for the
endovascular treatment (EVT) of brain arteriovenous malformations (AVMs).
• Comprised of Ethylene-Vinyl Alcohol copolymer (EVOH), tantalum powder for radiopacity in Dimethyl sulfoxide (DMSO) solvent, it offers some advantages over traditional adhesive liquids such as NBCA (acrylic glue) and has improved feasibility and safety of EVT of cerebral arteriovenous (AV) shunting lesions.
• Nevertheless, complications may occur, potentially attributable in part to its inferior radiographic visibility when compared to standard iodine-based vascular contrast medium.
Purpose:• We hypothesize that some of
these complications may be the result of loss of visual control during therapeutic Onyx® injections under fluoroscopy with subsequent “silent migration” or invisible reflux into small terminal arteries or via “dangerous anastomoses” causing inadvertent occlusion of normal territories.
• The purpose of this study was to evaluate the radiographic visualization of Onyx® in comparison to iodine-based contrast medium using a newly developed calibrated vascular model and state-of-the-art angiographic equipment.
Thalamoperforators
Thalamoperforators
Thalamoperforators (Rr. diencephalici inf.post.) may arise from the P1 segment, basilar artery or superior cerebellar
artery an can measure between 0.1 and 1.0 mm. They give off mammillary branches measuring between 0.12 and
0.37mm (120-370 micron) after Lang and Brunner, 1978. Drawing modified after J. Lang (Lanz & Wachsmuth,
Springer 1985)
Purpose:Many essential perforating cerebral vessels are known to have diameters as small as 120 microns and average in outer diameters ranging from 330 to 520 microns.
Given these known vessel sizes, we devised a model to test visualization of onyx between 100 and 500 microns.
Clival branches - “dangerous
anastomoses” from ECA to ICA
Thalamoperforators
This stepwise reduced diameter model was then connected to a microcatheter which allow for injections very similar to clinical
scenarios
Microcatheter
Microcatheter
500μ
350μ 250μ 175μ 100μ
Methods: A vascular model was built using tubing of stepwise reduced calibrated inside diameters: 500 microns, 380 microns, 250 microns, 175 microns
and 100 microns.
Methods:
The Model had identical outside diameters.
Small Gaps between different sections allows for easy visual identification that radiopaque material has passed through preceding section.
500μ
380μ 250μ 175μ 100μMicrocatheter Microcatheter
Methods: Philips Allura system under the following settings: • Cerebral 2 f/sec • Unsubtracted DSA• “Blank” Roadmap in• “Embo”- Mode 3 (high dose) • FD size = 6 inch• SID = 90 • Table Height = +5
Microcatheter Microcatheter
500μ
380μ 250μ 175μ 100μ
Injections performed with the following:
• Contrast - Standard vascular Iodine contrast medium (non-diluted Omnipaque® 300)
• Onyx – Onyx®-18, Ethylene-Vinyl Alcohol copolymer (EVOH), tantalum powder for radiopacity in Dimethyl sulfoxide (DMSO) solvent
Microcatheter
Microcatheter
Model
Model
Results: Model injected with contrast, unsubtracted DSA
Contrast in tubing
Results: Model injected with contrast, unsubtracted DSA
Model
Model
Results: Model injected with contrast, unsubtracted DSA
Microcatheter Microcatheter
Results: Model injected with contrast, unsubtracted DSA
Contrast entering
Contrast leaving
MicrocatheterMicrocatheter
Results: Model injected with contrast, unsubtracted DSA
Contrast in gaps between tubing
Small Gaps between different sections allows for easy visual identification that radiopaque material has passed through preceding section.
Results: Model injected with contrast, unsubtracted DSA
500μ
380μ 250μ 175μ 100μ
Contrast in tubing
500μ
380μ 250μ 175μ 100μ
The Model had identical outside diameters.
Results: Model injected with contrast, unsubtracted DSA
500μ
350μ 250μ 175μ 100μ
Stepwise reduced inside diameters
500μ
380μ 250μ 175μ 100μ
Mic
roca
thet
er
Mic
roca
thet
er
Results: Model injected with contrast, Roadmap
500μ
350μ 250μ 175μ 100μ
500μ
380μ 250μ 175μ 100μ
Stepwise reduced inside diameters
Mic
roca
thet
er
Mic
roca
thet
er
Results: Model injected with contrast, Roadmap
Microcatheter
Microcatheter
Contrast in gaps between tubing
Results: Onyx® vs. Contrast, unsubtracted DSA
Onyx
Contrast
Microcatheter
Microcatheter
Microcatheter
Microcatheter
Results: Onyx® vs. Contrast, unsubtracted DSA
Onyx
Contrast entering
Contrast leaving
Onyx entering
Oynx exiting
Contrast
Results: Onyx® vs. Contrast, unsubtracted DSA
Onyx seen in gaps between tubing
Contrast seen in gaps between tubing
Onyx
Contrast
Results: Onyx® vs. Contrast, unsubtracted DSA
500μ
380μ 250μ 175μ 100μ
Stepwise reduced inside diameters
Stepwise reduced inside diameters
350μ 250μ 175μ 100μ500μ
Onyx
Contrast
500μ
380μ 250μ 175μ 100μ
Mic
roca
thet
er
Mic
roca
thet
er
Results: Onyx® vs. Contrast, unsubtracted DSA
500μ
380μ 250μ 175μ
Beginning loss of visualization of contrast around 175 micron.
350μ 250μ 175μ 100μ500μ
Onyx
Contrast
500μ
380μ 250μ
Beginning loss of visualization of Onyx around 250 microns.
Mic
roca
thet
er
Mic
roca
thet
er
Results: Onyx® vs. Contrast, Roadmap
Onyx
500μ
380μ 250μ 175μ 100μ
Contrast
350μ 250μ 175μ 100μ500μ
500μ
380μ 250μ 175μ 100μ
Mic
roca
thet
er
Mic
roca
thet
er
Results: Onyx® vs. Contrast, Roadmap
Onyx seen entering gaps
Contrast seen entering gaps
Contrast
350μ 250μ 175μ 100μ500μ
Onyx
Mic
roca
thet
er
Mic
roca
thet
er
Results: Onyx® vs. Contrast, Roadmap
Beginning loss of visualization of contrast around 250 microns.
Contrast
500μ
380μ
500μ
380μ 250μ
350μ 250μ 175μ 100μ500μ
OnyxBeginning loss of visualization of Onyx® around 380 microns.
Mic
roca
thet
er
Mic
roca
thet
er
Conclusions 1:
1. A newly designed calibrated vascular model allowed evaluation and
comparison of radiographic visualization of contrast medium and a
liquid embolic agent under standardized and reproducible
experimental conditions.
2. Visualization of both contrast and Onyx®-18 is under “blank” Road
Map is inferior compared to unsubtracted DSA.
3. Loss of visual control during therapeutic injections of liquid embolic
agents, such as Onyx®-18 may occur earlier than previously known,
and thus may be associated with the risk of “silent migration” into
small perforating arteries, “dangerous anastomoses” or reflux
channels with potentially serious clinical consequences.
Conclusions 2:
1. This is to our knowledge the first visualization test for a
liquid embolic using a vascular model with a stepwise
calibrated decreasing diameter to simulate flux
conditions comparable to human vasculature.
2. This model could also be used to help test and calibrate
fluoroscopy and angiographic machines, compare
visualization between different manufacturers, as well
as test visualization of various contrast and liquid
embolic agents.
References:
1. Loffroy R, Guiu B, Cercueil J, Krause D. Endovascular
therapeutic embolisation: An overview of occluding agents and
their effects on embolised tissues. Current vascular
pharmacology. 2009;7(2):250-263.
2. Lang J. Clinical anatomy of the head: Neurocranium, orbit,
craniocervical regions. Springer-Verlag; 1983.
3. Brunner FX: Über die Arterien des Hirnstammes. Vorkommen,
Zahl, Durchmesser und Variationen. Thesis 1978, University
Würzburg.