DR K S PATIL JNMC BELGAVI KARNATAKA

1. EMBOLIZING AGENTS
CHAIRMAN : DR P H PATIL
CO-CHAIRMAN : DR V V HATTIHOLI
RESENTOR : DR K S Patil

2. WHAT IS EMBOLIZATION ?
 The therapeutic introduction of various
substance into the circulation to occlude vessels,
either to arrest or prevent haemorrhage, to
devitalize a structure, tumour or organ by
occluding its blood supply.

3. Therapeutic goals of Embolization
1. An adjective goal : preoperative, adjunct to
chemotherapy or radiotherapy.
2. A curative goal : definitive treatment in case of
aneurysm, AVFs, AVMs and traumatic bleeding.
3. A palliative goal : relieving symptoms such as large
AVMs

4. EMBOLIZATION MATERIAL AND SUBSTANCE
 History :
First agent used was AUTOLOGOUS BLOOD CLOT.
Method :Aspirate roughly 20 mL of the patient's blood
and allow it to clot, then discard the
supernatant and reintroduce the clot
through the catheter. If desired, the clot can
be opacified by adding sterile tantalum
powder.

6. AUTOLOGOUS BLOOD CLOT...
Advantage : Easily and quickly obtained
Absence of cost
Lack of adverse reaction(biocompatible).
Disadvantage : Recanalization occurs within hours to days
due to body’s natural clot lysis mechanism.
 Uses :
1. Autologous blood clot seal (ABCS) after biopsy of lung
lesions can reduce or prevent pneumothorax.
2.Epidural blood patch to relieve post dural puncture
headaches caused by lumbar puncture.
3. Posttraumatic non ischemic priapism

8. MODERN EMBOLIC AGENTS
 Temporary : Gel foam, collagen, thrombin
 Permanent :
 Particles: PVA(polyvinyl alcohol), Embospheres
 Coils : Pushables, Injectables, Detatchable
 Liquid agents : GLUE, ONYX, ALCOHOL, ALGEL
 Others : Amplatzer Plugs, Balloons.

9. Device selection :
 Vascular territory to be embolized
 Degree of occlusion—proximal or distal—desired
 Permanence of occlusion i.e Temporarary or Permanant

10. Permanent Large-Vessel Occlusions
 Coils- Pulmonary AVM
 Balloons
 Amplatz Vascular Plug

11. Permanent Small-Vessel Occlusions
 Particles
 Liquid sclerosants
 Liquid adhesive
 Ethiodol
 Thrombin
 Onyx

12. Temporary Large-Vessel Occlusions
 Gel foam sponge
 Autologous clot

13. Temporary Small-Vessel Occlusions
 Gel foam powder
 Starch microspheres
 Fibrillated collagen

15. 1.GELFOAM(GELATIN FOAM)
 It is made up of purified skin gelatin
 First used for cortico-cavernous fistula(1964)
 It is available in sterile sheets & powder.
 Gel foam is cut into 1-2 mm pieces
 Mixed with dilute contrast
 Injected as pledgets/ prepared as slurry

16. Mechanism of action of gel foam
 Its aggregates or swells on hydration into larger particles
Mechanical obstruction
Slowing of blood flow
Hastening thrombus formation

17. Gel foam
 Advantage :
 As it is temporary in nature advantageous in haemoptysis &
trauma
 Low cost
 Disadvantage :
 Can cause infection due to the trapped air bubbles
 Can lead to ischemia due to small size (< 70 µm)

18. If a very proximal occlusion is desired, Gelfoam “Torpedoes" can be
formed by compressing and rolling strips of Gelfoam, which are then
loaded into the nozzle of a 1- or 3-mL syringe.
Gelfoam Pledgets(pad) GelfoamTorpedo (a cigar-shaped self-propelled )

19. For more distal embolization, a slurry (a semi-liquid mixture) of Gelfoam can be
created by macerating the pledgets with two syringes and a three-way stopcock.
the more passes the Gelfoam makes through the stopcock, the more it is
fragmented and the smaller the pieces it become.
Gelfoam embolization provides a temporary occlusion lasting approximately 3 to 6
weeks.

20. PARTICLES-1)POLYVINYL ALCOHOL PARTICLES
 First used in 1974
 Permanent embolizing agent
 Particles are made from PVA sheets – vaccum dried & rasped
into particles
 Particles are filtered with sieves(filtering devices) and PVA is
available in sizes between 50 and 2000 µm, the typical size ranges
used clinically are 300 to 500 µm or 500 to 700 µm.

21. PVA Particles

22. Mechanism of action PVA
 PVA particles are irregular in shape which (oval, oblong,
irregular and angulated) promote aggregation.
 PVA particles :
Adherent to vessel wall
Stagnation of flow
Inflammatory reaction & focal angio-necrosis
Vessel fibrosis
Permanent occlusion

23. Uses :
 Uterine fibroid embolization -either for preoperative
devascularization or as definitive treatment.
 JNA (Juvenile nasopharyngealAngiofibroma)
embolization.
 Bronchial artery embolization.
 Portal vein embolization. etc

24. Disadvantage
 Occludes vessels from proximally due to irregular size.
 Can cause catheter occlusion which can lead to non targeted
embolization when catheter is flushed.
 Smaller particles have a significant risk of tissue infarction due to
their distal level of occlusion.

25. Bronchial artery embolization

26. Pre and Post Uterine Fibroid Embolization
Use of PVA Particles

27. 2.EMBOSPHERE:- TRIS-ACRYL GELATIN MICROSPHERES
 Embospheres are precisely calibrated, spherical, hydrophilic,
microporous beads made of an acrylic co-polymer, which is then
cross-linked with porcine gelatin.
 The hydrophilic surface prevents aggregation, allowing a more
predictable, uniform vessel occlusion than PVA, as well as easier
delivery through small catheters.
 Embospheres gold are coloured for visibility.

29. Diagrammatic representation

30. Diagrammatic representation

31.  SIR Spheres : Ceramic microspheres have been embedded
with the beta emitterYttrium-90. Provide internal
radiation of hepatic malignancies
 Calibrated particles with a tris acryl gelatin polymer core
and hydrophilic surface characteristics were obtained by
reversed emulsion synthesis followed by application of a
wet-sieving technique. Particles were suspended in saline,
bottled and sterilized

32. SIR Spheres microspheres

33. Mechanism of microsphere
 Same as PVA Particles.That is they
Adherent to vessel wall
Stagnation of flow
Inflammatory reaction & focal angio-necrosis
Vessel fibrosis
Permanent occlusion

34.  Advantage :
 Particles accumulation in catheter tube is uncommon
 Disadvantage :
 Needs intermittent brisk stirring to prevent
sedimentation.
 Embospheres are composed of porcine gelation which
has allergic potential
 Careful attention in sizing is required because same
size embosphere will penetrate more deeply compared
with PVA which could cause unintended ischemia.

35. Uses :
 In the treatment of fibroid by uterine artery embolization
 liver embolization in patients with metastatic neuroendocrine
tumors
 In the preoperative embolization of meningiomas
 Embolization of facial AVM

36. Diagrammatic representation

37. COILS
 First embolic coils consisted of pieces of stainless steel guide
wires onto which strands of wool had been woven to add a
matrix for thrombus formation.
 Stainless-steel coils are best suited for high-flow applications
due to their high radial force, which helps prevent dislodging.
 Platinum coils are highly visible under fluoroscopy and are
much softer than stainless steel.This facilitates
accommodation of the coil to the vessel.
 Appropriate sizing is important to ensure occlusion of the
vessel at the intended location.

38. MECHANISM OF ACTION
Coils in blood vessel
.
• Slowing of blood flow
.
• Thrombogenesis
.
• Clot formation
• Vessel wall damage
.
• Release of thrombogenic
factors
.
• Thrombogenesis
Thrombogenesis
• Clot formation

39. Coils ……
 Size - 0.008 to 0.052 inches
 Length – 1 to 300 mm
 Diameter – 1 to 27 mm
 Shape – J or C shaped, helical, conical, straight and complex
3D shapes.
 Coils may be bare or fibered with material such as dacrum,
nylon fiber, polyster, wool, silk or PVA (to increase
thermogenicity)

40.  Advantage :
 Easy to see, control and display
 Causes complete occlusion of vessels
 Disadvantage :
 Occlusion of non target vessels
 Coil migration
 Vessel dissection/ perforation
 Vessels rupture(soft coils are used to reduce incident)
 Infection
 Allergic reaction

41. COILS...
 In general coils should be sized 20 to 30 % larger than what
the vessel measures on pre deployment angiogram to prevent
distal embolization / migration.

42. USES OF COIL :
 Applications for coil embolization include treatment of hemorrhage –
Aneurysm.
 Occlusion of arteriovenous fistulas.
 Preoperative or pre-stent graft vessel occlusion.
* The main goal is prevention of rupture in unruptured
aneurysms, and prevention of rebleeding in ruptured aneurysms by
limiting blood circulation to the aneurysm space
* Embolization with coils produces a focal occlusion, leaving
the vessel distal to the coil patent, similar to surgical ligature.
Therefore, coils are utilized in almost any application in which precise
vessel occlusion--but not tissue ablation--is necessary.

43. COILS-Methods of delivery
1. Push able coils
2. Inject able coils
3. Detachable coils
A. Mechanical
B. Electrolytic
C. Hydrolytic

44. Detachable Coils
Used in Intracranial Aneurysm
Coiling.
Pushable Coils
Used in Peripheral Embolization.

45. Endovascular Coiling of
Intracranial Aneurysms

46. 1.PUSHABLE COILS
 Most commonly used
 Special guide wire with bulbous tip is used to physically push the
coil through an end hole catheter into a desired position
 Advantage : 1.Ready availability,
2.Relative cost and easy to use
 Disadvantage : 1.Reposition is not possible,
2.Can be trapped at sharp curves of vessels.
3.If incompatible with the catheter, can
become irretrievably jammed in the catheter

47. 3/4/2017 47
Bilateral uterine arteries were embolised using pushable coils.

48. 2.INJECTABLE COILS(LIQUID COILS)
 These are the soft, non fibered platinum coils of 0.008 to 0.016 inch in
diameter.
 Injection through a catheter via a small syringe with saline
 Quicker method
 Liquid coils are deployed by forceful injection of contrast through the
catheter after loading the coil.
 Advantage : Tight coil compaction
Ability to accommodate to tortuous anatomy
Ability to flow to a target distal to the catheter if
required
Disadvantage :Vigorous injection can result in pushing the catheter
back substantially and risking non target embolization

49. 3.DETACHABLE COILS
 The first detachable coil was described in 1977 by Professor
Cesare Gianturco.
 Cesare first used these coils to embolize renal tumors
 These coils are not routinely used.
 It is non fibered, extremely soft.
 Uncoated platinum coil fixed to a stainless steel delivery wire.
 They come in a variety of shapes such as– 3D basket type,2D
helical type.
 Current detachable coils deploy by a variety of mechanisms
including mechanically, by electrolysis, and via hydrostatic
means
 Used in AVM and Aneurysms.

50. Detachable coils….
 Disadvantage :1) expensive, 2)large setup time
3) the coil can rotate or flip at detachment by
inadvertent detachment during wire manipulation.
 The disadvantage of this system is that there is often friction
between the microcoil and microcatheter

51. A)MECHANICAL
 Mechanical detachment includes interlocking mechanical
detachment and screw-release mechanisms.The interlocking
mechanism uses small metal beads, or hinge, at the proximal
coil tip and end of the wire.The coil is fastened by overlapping
the beads hinge.Within the catheter the coil is attached, but
once out of the catheter the beads separate and the coil is
released.
 The disadvantage: friction between the microcoil and
microcatheter.

52. B)Electrolytic coils(GDC-Gugliemi detachable coil)
 Electrolytic detachment coil was designed and first used
by Dr. Guido Guglielmi in 1991
 The original GDC is a non-fibered, extremely soft,
uncoated platinum coil affixed to a stainless steel delivery
wire
 Coil is welded to the pusher wire in the desired position.

53. Electrolytic coils….
 The wire is attached to a battery device.
 The current melts the welded connection between the coil
and the wire and detaches the coil.
 Currently, the platinum coil is welded to platinum-
tungsten alloy and has a highly successful deployment
rate
 A 1-mA current is used to detach the coil at the weld point.
A 2-mA current can alternatively be used to detach the
coil more quickly

54. Electrolytic coils
 Advantage :
 Minimally invasive
 Requires less time than surgery
 Disadvantage :
 Expensive

55. C) HYDROGEL COILS
 It is a detachable platinum coils(0.008-to-0.016-inch diameters)
coated with an expandable polymer.
 When detached in the vasculature > polymer expands> coil
diameter increases from 0.014 to 0.027 inches.
 Complete expansion occurs within 20 minutes.
 These are extremely soft, non fibered platinum coils of.
Although made of metal, liquid coils can be delivered across
tight bends and conform to the space into which they are
injected

56. Hydrogel COILS….
 Advantage : 1.greater volume expansion & occlusion than
regular coil
2. Do not depend on thrombus formation
3.ability to accommodate to tortuous anatomy,
and ability to flow to a target distal to the catheter if desired
 Disadvantage : 1.coil can get struck in the catheter if the coil is
not compatible with the delivery system.

58. OTHERS – 1)DETACHABLE BALLOON
 It was first used in 1974
 Balloon is made up of latex of size 6 to 14 mm and silicon size
6 to 10 mm.
 Uses : cortico- cavernous fistula, pulmonary AVMs, large
vessel occlusion.
 Advantage : Ability to occlude large vessel.
possible reposition.
 Disadvantage : Rupture of vessels, deflation, migration and
premature detachement.

60. 2.AMPLATZER VASCULAR PLUG
 It is a new device (expandable nitinol mesh occlusion device)
 Amplatzer I – simple thick disk 4 to 16 mm
 Amplatzer II – thin disk 3 to 22 mm
 They have stainless steel screw attachment to delivery wire &
radio- opaque marker bands at both ends.
 USES : Internal iliac artery, mesenteric artery, Renal artery,
Portal vein, Splenic Artery.

62.  Advantage : reduces need for multiple coil hence saves money
and time.
 Disadvantage : used in straight segment of vessel which dose
not taper. Does not cause immediate thrombosis.They are not
fibered & depend on patient’s ability to form thrombus

63. PERMANENT LIQUID AGENTS – 1.GLUE
 Glue (N-BUTYL- 2 CRYNOACRYLATE - NBCA)
 Preperation :
 1 gm of tubes of NBCA – free monomer, when expended to
anionic environment(blood & water ) polymerization occurs.
 10 ml ethiodized oil(Made from iodine and poppyseed oil) –
vehicle and acts as a polymerization occurs.
 1gm of tantalum powder – provides radiographic opacification
and initiates polymerization

64. MECHANISM OF ACTION
Glue adherent to vessel wall
Inflammatory reaction
Chronic inflammation
Polymerization of glue starts immediately on contact with anion

65. Glue …
 To avoid unintended polymerization by premature contact
with anion catheter should be flushed with 5% dextrose in
water intermittently.
 That is why it requires special set up i.e 3 way stopcock
(syringe for NBCA and 5% dextrose)
 Immediately after glue injection, catheter tip is retracted to
avoid catheter adhesion .

66. Glue …
 Advantage : 1. permanent
2. completely occludes the vessels
3. works instantly
 Disadvantage : 1.Can get entrapped in the occluded vessel.
2.Require expertise,
3.Polymerization can spread distally or reflux
proximally to the intended lesion.

67. 2.ONYX(ETHYLENE VINYL ALCOHOL CO-POLYMER-EVOH)
 First used as embolic agent by Dr taki in 1990
 Co-polymer of ethylene vinyl alcohol, prepared with dimethyl
sulfoxide.
 Opacification material used is tantalum powder. After Onyx is
injected into the target lesion, the dimethyl sulfoxide solvent
rapidly diffuses away, causing precipitation of the polymer
and formation of a spongy cast.
 Used mainly in Cerebral and Peripheral AVM emboization

68. Onyx
Used for embolization of Cerebral AVMs,
Peripheral AVMs.

70. MECHANISM OF ACTION- ONYX
Onyx / EVOH on contact with blood
DMSO (dimethyl sulfoxide) diffuse away
Polymerization of EVOH
Forms a cast

71. PROCEDURE:
 EVOH comes with separate vail of DMSO and DMSO
compatible catheters should be used for procedure.
Catheter is placed in place
DMSO is injected to fill the catheter dead space
Which inhibits in catheter polymerization of EVOH
EVOH is injected under fluoroscopy guidance

72.  Advantage : Non adhesive allows longer injection times
and ability to temporally suspend embolization which
allows further procedure during angiography.
 Disadvantage : Need DMSO compatible catheter
DMSO is toxic and rapid injction causes
vasospasm and necrosis.
• Use : in cerebral AVM
• Injection Rate : < 0.3 ml/ > 40 seconds

73. ONYX

74. 3.ABSOLUTE ALCOHOL
 MECHANISM OF ACTION :
Absolute Alcohol
Denaturation of proteins
Thrombosis
Fibrosis
Infarction

75.  Advantage : Less cost, easily available
 Disadvantage :
Difficulty to control placement
Lack of opacity
Rapid dilution by vascular inflow

76. 4.CALCIUM ALGINATE GEL (ALGEL)
 It is polymer of alginic acid
 Procedure :
Calcium alginate
Liquide alginate (premixed with contrast for visibility)
Calcium chloride
Forms a non adhesive gel foam

77.  Advantage :
1.Unlike coils, gel fills the entire structure to be occluded
2.Catheter occlusion is less likely because two components
are injected separately
 Disadvantage : Requires expertise.

78. SCLEROSING AGENTS
 Cause protein denaturation, leading to endothelial destruction
and vascular occlusion. Occlusion by sclerosants is usually
permanent.
 Sodium tetradecyl sulfate (Setrol) and Polidocanol
 Uses : ablation of tumours, solid organs, veins, or vascular
malformations.

80. `
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