peripheral avm

Peripheral AVM: endovascular Peripheral AVM: endovascular managementmanagement

Dr. Hazem Habboub Dr. Hazem Habboub

King Hussein Medical CenterKing Hussein Medical CenterAmman - JordanAmman - Jordan

INTRODUCTION INTRODUCTION

Vascular malformations Vascular malformations are among the most common are among the most common congenital abnormalities observed in infants and children. congenital abnormalities observed in infants and children. Unfortunately, these lesions are also among the most Unfortunately, these lesions are also among the most confusing and misunderstood conditions, largely because confusing and misunderstood conditions, largely because of a history of inconsistent terminology used for of a history of inconsistent terminology used for classification. classification.

Vascular malformations Vascular malformations are considered a group of are considered a group of conditions typified by localized defects in vascular conditions typified by localized defects in vascular morphogenesis caused by dysfunction in embryogenesis morphogenesis caused by dysfunction in embryogenesis and vasculogenesisand vasculogenesis

Vascular MalformationsVascular MalformationsDiffuse disorder of vascular anomalies.Diffuse disorder of vascular anomalies.1982 : Mulliken and Glowacki: 2 groups1982 : Mulliken and Glowacki: 2 groups

HaemangiomasHaemangiomasVascular MalformationsVascular Malformations

1992: International society for the study of vascular 1992: International society for the study of vascular anomalies-ISSVA- sentinel classificationanomalies-ISSVA- sentinel classification--Vascular tumorsVascular tumors-vascular malformations: Divided by Dynamic flow -vascular malformations: Divided by Dynamic flow characteristic: High flow and Low flow.characteristic: High flow and Low flow.

Agenda:Agenda:DifferentiationDifferentiationDiagnosisDiagnosisTreatmentTreatment

Arteriovenous malformations

-Vascular malformations are often referred to as -Vascular malformations are often referred to as ““iceberg lesionsiceberg lesions””--Clinical history and Clinical history and examinationexamination can usually differentiate high can usually differentiate high and low flow lesions with imaging being used to: 1.confirm the and low flow lesions with imaging being used to: 1.confirm the diagnosis, 2. evaluate morphology and 3. to plan treatment.diagnosis, 2. evaluate morphology and 3. to plan treatment.

--Treatment is generally reserved for those patients with significant symptomatic lesions or cosmetic defects

PATHOPHYSIOLOGYPATHOPHYSIOLOGY Vascular Malformations:Vascular Malformations:

High-flow Vascular MalformationsHigh-flow Vascular Malformations Arteriovenous malformations Arteriovenous malformations are considered to be congenital are considered to be congenital

vascular anomalies, but are usually first noted several years after vascular anomalies, but are usually first noted several years after birth or after certain triggering changes such as trauma or the birth or after certain triggering changes such as trauma or the hormonal changes of puberty or pregnancy. hormonal changes of puberty or pregnancy.

Arteriovenous fistulas (AVFs)Arteriovenous fistulas (AVFs) are simple arteriovenous connections. are simple arteriovenous connections. Most AVFs are secondary to penetrating injuries after birth, Most AVFs are secondary to penetrating injuries after birth, although some are believed to be congenital.although some are believed to be congenital.

PATHOPHYSIOLOGYPATHOPHYSIOLOGY Vascular Malformations:Vascular Malformations:

High-flow Vascular MalformationsHigh-flow Vascular Malformations An AVM is an abnormal connection or connections between an An AVM is an abnormal connection or connections between an

artery and vein .In this situation blood bypasses the capillary network artery and vein .In this situation blood bypasses the capillary network within organs and tissues and the normal pressure down regulation does within organs and tissues and the normal pressure down regulation does not occur. The first dilated segment of vein after this connection is not occur. The first dilated segment of vein after this connection is termed the termed the “nidus”.“nidus”.

Histological Analysis of AVMsHistological Analysis of AVMs Histological analysis of AVMs has shed some light on Histological analysis of AVMs has shed some light on

their pathogenesistheir pathogenesis Examination of specimens revealed that a nidus is made Examination of specimens revealed that a nidus is made

up of a bed of dilated capillaries.up of a bed of dilated capillaries. As the lesion matures, the degree of ectasia increases, and As the lesion matures, the degree of ectasia increases, and

the development of venous dilation and arterial the development of venous dilation and arterial hypertrophy becomes apparent.hypertrophy becomes apparent.

The primary abnormality or nidus, therefore, appears to The primary abnormality or nidus, therefore, appears to be an be an ectatic capillary bed.ectatic capillary bed.

Arterial hypertrophy and venous dilation are secondary Arterial hypertrophy and venous dilation are secondary phenomena that result from the increase flow across the phenomena that result from the increase flow across the nidus.nidus.

Histological Analysis of AVMs Histological Analysis of AVMs (continued(continued((

Because the nidus is simply an ectatic capillary bed and because the Because the nidus is simply an ectatic capillary bed and because the precapillary sphincters regulate the blood flow through the precapillary sphincters regulate the blood flow through the capillary bed, we believe that arteriovenous malformations result capillary bed, we believe that arteriovenous malformations result from an abnormality at the level of the from an abnormality at the level of the precapillary sphincterprecapillary sphincter..

An absence of autonomic nerve supply to the sphincters, an An absence of autonomic nerve supply to the sphincters, an absence of the actual sphincters, or some deficiency in the absence of the actual sphincters, or some deficiency in the neuroreceptors at this level will result in free flow across that neuroreceptors at this level will result in free flow across that particular capillary bed.particular capillary bed.

In time, the vessels in the bed dilate, and eventually the area In time, the vessels in the bed dilate, and eventually the area supplying the arteries enlarge and the veins dilate. supplying the arteries enlarge and the veins dilate.

This absence of capillary sphincter control may be absolute or This absence of capillary sphincter control may be absolute or relative, hence the variation in age of presentation and speed of relative, hence the variation in age of presentation and speed of progression.progression.

AVMs Growth and Bleeding AVMs Growth and Bleeding CycleCycle? ?

Some people are born with the nidus. As years go by, it tends to Some people are born with the nidus. As years go by, it tends to enlarge as the pressure of the arterial vessels cannot be handled by enlarge as the pressure of the arterial vessels cannot be handled by the veins that drain out of it. the veins that drain out of it.

Most of these malformations bleed between the ages of 10-55; Most of these malformations bleed between the ages of 10-55; after 55, the chances of bleeding diminishes rapidly. Before 55, after 55, the chances of bleeding diminishes rapidly. Before 55, the likelihood of hemorrhaging is between 3-4% per year (with a the likelihood of hemorrhaging is between 3-4% per year (with a death incidence of about 1%). death incidence of about 1%).

Once a patient has hemorrhaged, the risk of having another one Once a patient has hemorrhaged, the risk of having another one may approach 20% during the first year, and will gradually lessen may approach 20% during the first year, and will gradually lessen to about 3-4% over the next few years.to about 3-4% over the next few years.

What Are Some AVM StatisticsWhat Are Some AVM Statistics AMVs affect approximately 300,000 Americans.AMVs affect approximately 300,000 Americans. In the Netherlands between 1980 and 1990, the annual incidence In the Netherlands between 1980 and 1990, the annual incidence

of symptomatic AVMs was 1.1 per 100,000 population. of symptomatic AVMs was 1.1 per 100,000 population. They occur equally in males and females from all ethnic and racial They occur equally in males and females from all ethnic and racial

backgrounds.backgrounds. They are more prevalent in late childhood (over 9 years of age) They are more prevalent in late childhood (over 9 years of age)

than early childhood, although they can occur at any age.than early childhood, although they can occur at any age. More than 50% present with intracranial AVMs. More than 50% present with intracranial AVMs. About 12% of the affected population will present with symptoms About 12% of the affected population will present with symptoms

that vary greatly in severity. that vary greatly in severity. Each year about 1% of those with AVMs will die as a direct result Each year about 1% of those with AVMs will die as a direct result

of the AVM. of the AVM.

PATHOPHYSIOLOGYPATHOPHYSIOLOGY Vascular Malformations:Vascular Malformations:

High-flow Vascular MalformationsHigh-flow Vascular MalformationsClassification:Hudart Classification

-Type 3 is the commonest(>60%). And most difficult to treat.

Type 1 Arteriovenous No more than 3 separate arteries

Type 2 Arteriolovenous Multiple arteries shunt to a single vein

Type 3 Arteriolovenulous Multiple shunts between arteries and venules. Multiple nidi

Vascular Malformations:Vascular Malformations: High-flow Vascular MalformationsHigh-flow Vascular MalformationsClinical features:Depends on the region of involvement & degree of shunting Pain Overgrowth Bleeding High cardiac output: less common, large AV shunt Rapid growth over short time, Swelling ,especially after trauma. Schobinger

Schobinger classification

Type 1 Queiscent-stable

Type2 Growing

Type3 Symptomatic:Pain ,bleeding,functional problems

Type4 Decompensating,high flow cardiac output

SIGNS AND SYMPTOMSSIGNS AND SYMPTOMS

Vascular Malformations:Vascular Malformations: High-flow Vascular MalformationsHigh-flow Vascular Malformations

Arteriovenous malformations (AVMs) are generally present in neonates at Arteriovenous malformations (AVMs) are generally present in neonates at birth, but they often suddenly become obvious when the patient is older birth, but they often suddenly become obvious when the patient is older because of various stimuli such as trauma, pregnancy, or puberty. There are because of various stimuli such as trauma, pregnancy, or puberty. There are four recognized stages of AVMs:four recognized stages of AVMs:

Stage IStage I lesion has a pinkish-bluish stain and warmth. lesion has a pinkish-bluish stain and warmth. Stage IIStage II, the lesion has pulsations, thrill, and bruit. , the lesion has pulsations, thrill, and bruit. Stage IIIStage III, the patient has dystrophic skin changes, ulceration, bleeding, , the patient has dystrophic skin changes, ulceration, bleeding,

and pain. and pain. Stage IVStage IV, the patient has high-output cardiac failure., the patient has high-output cardiac failure.

High-flow Vascular MalformationsHigh-flow Vascular Malformations

Vascular Malformations:Vascular Malformations: High-flow Vascular MalformationsHigh-flow Vascular MalformationsDiagnosis:Diagnosis is typically clinical with an area of abnormality within skin, Diagnosis is typically clinical with an area of abnormality within skin,

presenting as a pulsatile mass, thrill, warmth and redness presenting as a pulsatile mass, thrill, warmth and redness

Vascular Malformations:Vascular Malformations: High-flow Vascular MalformationsHigh-flow Vascular MalformationsImaging: Ultrasound: Diagnostic. Reveals multiple vascular channels with high

flow and loss of normal venous damping on Doppler

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High flow characteristics post traumatic AVM

TREATMENTTREATMENT High-flow Malformations:High-flow Malformations:

Surgical treatment:Surgical treatment: Small, superficial arteriovenous malformations can be removed surgically. However according to Szilagy (editor of Journal of vascular surgery)” with few exceptions ,AVM cure by surgical means is impossible”. Out of 82 patients with AVM , only 18 were suitable for operation. At FU, 6 were improved and 12 were worse.

Embolization:Embolization: It has been the only feasible treatment It has been the only feasible treatment option for most arteriovenous malformations. option for most arteriovenous malformations. Embolization, which closes off the arterial feeders of Embolization, which closes off the arterial feeders of the malformation, is generally effective in arteriovenous the malformation, is generally effective in arteriovenous malformations to stabilize the malformation. malformations to stabilize the malformation.

Vascular Malformations:Vascular Malformations: High-flow Vascular MalformationsHigh-flow Vascular MalformationsTreatmentNo agreement on the protocols for treatment. Best method to access

and treat AVM.The most single dominator for treatment is operator experience.A number of access route is available:

-Trans arterial: most common used with grade 2,3&4-direct stick: with type 1, slow venous flow-Transvenous: if there is a single draining vein, small nidus

Vascular Malformations:Vascular Malformations: High-flow Vascular MalformationsHigh-flow Vascular MalformationsTreatmentEmbolic agents:No unified agreement on agent of choice.Depends on: Experience. Availability, location, morphologyWide range of agents :

Particulate – Gel foam. PVA .EmbospheresParticulate – Gel foam. PVA .Embospheres Coils – 035”.018”.controlled releaseCoils – 035”.018”.controlled release Liquids – Alcohol.Alcohol/Lipiodol.GlueLiquids – Alcohol.Alcohol/Lipiodol.Glue Sclerosants – STD.PolidocanolSclerosants – STD.Polidocanol GlueGlue Detachable balloons Detachable balloons Occlusion devices. PlugsOcclusion devices. Plugs

035” coils

Polyvinyl Alcohol

Vascular Malformations:Vascular Malformations: High-flow Vascular MalformationsHigh-flow Vascular MalformationsTreatment

Onyx: Ethylene vinyl alcohol copolymer, relatively new non adhesive liquid agent that contains tantalum for radio opacity.

It precipitates on contact with aqueous solution. It is the most useful for type2,3 and 4. in our practice >90% of AVMs are treated with Onyx. As

the Flow dynamics of onyx has the greatest potential to occlude the AVM nidus

Goal of the treatment

Artery Vein

Glue occlusion mechanism

NBCA solidification obeys the polymerization law

Contact

with blood

Time of polymerization depends of 3 major variables:Liquid TemperatureVolume of LipiodolSpeed of injection

Polymerization phenomenon =

sticking phenomenon

Artery Vein

Sticking

Fragmentation

Glue occlusion mechanism

Usual situation

Proximal occlusion

Glue occlusion mechanism

Dangerous situation

Glue occlusion mechanism

Constitution: Ethylene vinyl alcohol (EVOH) resin Dimethyl sulfoxide (DMSO(

Tantalum powder

Onyx solidification obeys the precipitation law

Onyx occlusion mechanism

Onyx fills the vessel in a concentric way

Onyx progression obeys to the resistance variation law

R

R

R

R

R=8nl/πr4Poiseuil

Transarterial embolization with Onyx. Multiple sessions

AVM of the hand. Slow venous filling. Direct stick with Foam.Marked reduction in nidus filling.Resolution of symptoms

Challenges of the treatment:Challenges of the treatment:Strategy. Strategy. Number of sessions: 6-8 weeksNumber of sessions: 6-8 weekswhen to stop at each sessionwhen to stop at each session

Techniques to improve embolizationTechniques to improve embolizationPressure cooker techniqueDual catheter technique

Simple catheter techniqueSimple catheter technique

Hope

DangerDanger

Hope

EnlargementRemnant •Ischemia

•Hides the remnanthemorrhage

Double catheter techniqueDouble catheter technique

FirstFirst

Double catheter techniqueDouble catheter technique

SecondSecond

35 Y.O. Female35 Y.O. Female Frontal and supraorbital AVMFrontal and supraorbital AVM 3 endovascular treatments using glue in 2000 3 endovascular treatments using glue in 2000

followed by Radiosurgery (Gama Knife) in 2001followed by Radiosurgery (Gama Knife) in 2001 In 2008, 7 years later, new seizure In 2008, 7 years later, new seizure

AngiogramAngiogram

Right ECARight ECA

Middle meningeal artery navigation Middle meningeal artery navigation (ECA)(ECA)

Microcatheter 1Microcatheter 1

CM selective injectionMicrocatheter 1

Frontal artery navigation (ICA)Frontal artery navigation (ICA)Microcatheter 2Microcatheter 2

CM selective injectionMicrocatheter 2

Cath. 1 Cath. 2

Cath. 1 Cath. 2

Both microcatheters tips before Onyx injectionBoth microcatheters tips before Onyx injection

Onyx intranidal difusionOnyx intranidal difusion

veine veine

Nidal remnant after Onyx injection and Nidal remnant after Onyx injection and micro catheters retrievalmicro catheters retrieval

Glue injection(GlubranGlue injection(Glubran(:( :

Final controlFinal control::

Pressure cooker technique:Pressure cooker technique:Using coil+ or glue, then inject onyx Using coil+ or glue, then inject onyx

for deep penetrationfor deep penetration

ConclusionConclusion--Treatment of peripheral AVM is challenging and Treatment of peripheral AVM is challenging and requires a multidisciplinary team.requires a multidisciplinary team.-experience and understanding the capabilities and -experience and understanding the capabilities and physics of the embolic agent will determine the physics of the embolic agent will determine the success of treatment.success of treatment.-Embolization is proving effective as a stand alone -Embolization is proving effective as a stand alone option” with the proper use of the controlled liquid option” with the proper use of the controlled liquid embolic agents.embolic agents.