Endovascular Therapy for Peripheral Arteriovenous Malformations:

Case Series and Pictorial Review for Techniques

Chia-An Wu1, Chien-An Liu1,2, Hsuan-En Hwang1,2, Hsiou-Shan Tzeng1,2,3, Nai-Chi Chiu1,2, Yu-Chi Cheng1,

Rheun-Chuan Lee1,2, Chao-Bao Luo1,2

1Department of Radiology, Taipei Veterans General Hospital2School of Medicine, National Yang-Ming University, Taiwan

3Department of Radiology, Cheng Hsin General Hospital1

IntroductionArteriovenous malformations (AVMs) are abnormal vascular shunts between arteries and veins with a central nidus.

Given the high recurrence rate associated with surgical resection, endovascular therapy (EVT) has emerged to be an effective and less invasive treatment option.

Outline of this presentation: • Angiographic classification of peripheral AVMs• Brief introduction of embolic materials• Results of our case series• Case demonstrations• Reference

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Classification of AVMType I IIa IIb IIc

Definition Arteriovenous fistulae: no more than 3separate arteries shunt (S) to the initial part of a single drainage vein

Arteriolovenous fistulae: multiple arterioles (A) shunt (S) to the initial part of a single venous component (V), in which the arterial components show a plexiform appearance

Multiple arterioles + focal segment ofsingle draining vein

Multiple arterioles + venous sac + multiple draining veins

Multiple arterioles shunt + long segment draining vein

TreatmentStrategy

• DP or TV approach • Focal venous sac: coils

• DP + coils• Transarterial injection

• DP or TV approach • Coiling long segment vein

Notes • Rare • Type II: the best results of ethanol embolotherapy• Direct puncture (DP) or transvenous (TV) approach +/- coiling draining vein excellent outcomes • Transarterial approach: used predominantly to embolize residual small AVMs

Cho SK et al., J Endovasc Ther. 2006Ko SE et al., J Vasc Interv Radiol. 2019

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Type IIIa IIIb

Definition Arteriolovenulous fistulae: multiple shunts between arterioles and venules

Fine multiple, non-dilated shunts Plexiform, dilated shunts

TreatmentStrategy

• Difficult: only TA access is available • TA and DP• If no suitable access consider TA first

Notes • The most common type: IIIb.• TV approach is contraindicated for type III will not reach shunts block venous drainage hemorrhage

Classification of AVM

Cho SK et al., J Endovasc Ther. 2006Ko SE et al., J Vasc Interv Radiol. 2019

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Embolic MaterialsAgent Ethanol OnyxMechanism Induce protein denaturation of the endothelial cells

→ vessel wall denudation & thrombus formationEthylene vinyl alcohol copolymer dissolved in DMSO.Blood DMSO diffuses precipitation, solidification an elastic soft, non-adherent mass

Advantage • Low recanalization rate:permanently damages the endothelium of the nidus

• Low risk of catheter gluing to the arterial wall• Good penetration; transembolization angiography• Preservation of the option for subsequent surgical

resection: non-adhesive, low inflammatory reaction

DisadvantageComplications

• Very painful: general anesthesia is required• Complication rate: 10-30%

• Significant edema, skin necrosis, nerve damage • Dose-dependent risk of pulmonary

hypertension, cardiovascular collapse

• More expensive• Chemical irritation of DMSO→ painful need sedation• Need slow injection→ longer treatment times• Requires DMSO-compatible microcatheters• Dark skin discoloration (uncommon)

Notes • Suggest intraprocedural pulmonary arterial pressure (PAP) monitoring during procedure

• Single bolus injection of absolute ethanol > 0.14 mL/kgof body weight compromise right ventricular function

• Can be mixed with iodized oil (Lipiodol) for visualization

• Maximum injection rate = 0.1mL/min: to avoid vasospasm caused by DMSO

• If reflux is seen around the catheter: injection should be stopped for up to 2 minutes

• Patient may have garlic-like smell during respiration afterthe procedure

Shin BS et al., J Vasc Interv Radiol. 2010Vogelzang RL et al., J Vasc Interv Radiol., 2014Dunham GM et al., Radiographics, 2016

Do YS et al., Radiology, 2005Cho SK et al., J Endovasc Ther. 2006Ko JS et al., J Vasc Interv Radiol. 2009

5Numan F et al., J Vasc Interv Radiol. 2004

Saeed Kilani M et al., Diagn Interv Imaging. 2017K Lam et al., Applied Radiology. 2017Le Daré B et al., J Pharm Pharm Sci., 2019

Embolic MaterialsAgent n-BCA PVA particles Coils/ PlugsMechanism N-butyl cyanoacrylate

polymerizes quickly and irreversibly when exposed to anions

Polyvinyl alcohol Coils, plugs, core-removed guide wires

Advantage • Preferred in AVMs with large draining veins:require great amounts of ethanol or Onyx

• Pediatric population: ethanol dosing needs to be limited

• Effective in coagulopathy population

• Pre-surgical adjunct or in the management of an acutely bleeding AVM

• Adjunct: useful agents for outflow occlusion, especially in nidi with a dominant outflow vein

DisadvantageComplications

• Formation of glue masses: infection; erosion• Rapid polymerization in blood difficult to achieve precise occlusion

• Microcatheter cannot be reused no transembolization angiograms

• Non-target embolization due to selection of improper particle size

• Sizemay limit future vascular access if subsequent embolization is required

• High flow→ displace, migrate

Notes • Minimize premature polymerization: diluted with non-ionic solvent (Lipiodol) and the catheter flushed with 5% dextrose solution

• Generally, the use of PVA particles alone in the management of AVMs is notrecommended

• Have been used as stand-alone therapy exclusively in pulmonary and renal AVMs

6Dunham GM et al., Radiographics, 2016Saeed Kilani M et al., Diagn Interv Imaging. 2017K Lam et al., Applied Radiology. 2017

Ko JS et al., J Vasc Interv Radiol. 2009Shin BS et al., J Vasc Interv Radiol. 2010Vogelzang RL et al., J Vasc Interv Radiol., 2014

Numan F et al., J Vasc Interv Radiol. 2004Do YS et al., Radiology, 2005Cho SK et al., J Endovasc Ther. 2006

Results of Our Case Series From November 2003 to October 2019, 24 patients (16 men; mean age, 43 years)with peripheral AVMs undergoing EVT at our institute were enrolled in this series.

Their clinical presentations depended on AVM location. Local swelling and pain are the most frequent complaints in these patients.

The most common AVM type was IIIb.7

Results of Our Case Series Twelve cases were embolized by combination of different embolic agents.

Transarterial access was most frequently used (92%) with or without other access, and direct puncture was used in 20% cases.

Complete (> 90%) and nearly complete (50-89%) devascularization were obtained in 71% patients.

Clinical improvement within three months was achieved in all cases.

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(A) Initial angiography reveals type IIb left pelvic AVM, with feeding arteries from the anterior division of the left internal iliac artery, and one drainage vein towards right internal iliac vein. (B) Direct puncture of the major drainage vein with 0.018-inch Neff percutaneous puncture set (Cook Medical) was performed under syngo DynaCT (Siemens Healthineers) guidance. The tract was secured with a 5 Fr. short angiosheath. (C) (D) (E) Five sets of core-removed J-tip (0.035 inch x 80cm) guidewires and 30 Nester embolization coils were introduced towards nidus via venous route. Four mL alcohol mixed with 1 mL Lipiodol was injected via arterial route. She received three sessions of embolotherapy, with a combination of n-BCA, ethanol (mixed with Lipiodol), coils, and Onyx. Microballoon catheter for arterial side flow control was applied during Onyx injection. (Not shown) (F) Post-treatment angiogram in the last session revealed more than 90% devascularization of the nidus.

Case 1 A 54-year-old woman presented with intermittent claudication and mild lower abdominal discomfort for several months; type IIb left pelvic AVM

A B

C

F

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S/p embolization by core-removed guidewires, coils, ethanol, n-BCA, Onyx in 3 sessions

D

E

(A) (B) On initial angiography, there are multiple dilated and winding blood vessels at the anterior division of right internal iliac artery, with a dilated vascular sac draining into the internal iliac vein. (C) (D) Transarterial approach was applied in this case, with a 4-Fr. Cobra catheter, and a 5-Fr. Navien Support catheter. Two Scepter balloon catheters (Microvention, Tustin CA) (4-15 mm and 4-11 mm) were used for arterial flow control and slowly Onyx 18 injection. (E) Completion angiogram demonstrating more than 90% devascularization of the nidus.

Case 2 Type IIa right pelvic AVM in a 72-year-old male patient treated with transarterial approach and Onyx injection. Embolization was performed under general anesthesia.

Onyx 18 injection

Main draining vein

A B C

D

EBalloon catheter

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Case 3 Images from a 36-year-old male patient with a type IIb left pelvic AVM, embolized by coils and n-BCA.

(A) Pretreatment angiogram shows multiple feeding arterioles with an engorged venous sac, and some small draining veins from the sac. (B) Embolization was performed via transvenous approach, with a 4-Fr. Cobra catheter, and a 2.5 Fr. Cantata microcatheter. (C) The venous sac was embolized with eight 10-mm 14-cm Nester coils. Then,1 via n-BCA mixed with 2 mL Lipiodol was injected. (D) Completion angiogram shows nearly total obliteration of the nidus. The patient’s pelvic pain was markedly resolved after treatment.

Nester coils

N-BCA

Main draining vein

Venous sac

A B

C

D

Transvenousapproach

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Case 4 A 19-year-old man with a type IIIa right lower limb AVM presented with right lower leg swelling, numbness and non-healing ulcerations.

(A)(B) Right lower limb arteriography via direct right femoral artery puncture shows multiple small feeding arterioles and draining veins. (C)(D) Using 4-Fr. Cobra catheter and a 2.7-Fr microcatheter, we superselected multiple small feeding arterioles from posterior tibial artery and distal anterior tibial artery. With pressure cuff protection, 95% alcohol was injected smoothly. About 20ml 95% alcohol was administered in the treatment course. (E)(F) Completion angiogram demonstrates nearly total obliteration of the nidus.

A B C

D

E F

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Case 5 Type IIb right forearm AVM in a 64-year-old man treated by ethanol and Onyx injection in three sessions.

This patient underwent three sessions of embolization. Ethanol injection was performed in the first session. (A) Pre-treatment angiogram in the second session shows recurrent right forearm AVM, which was embolized by Onyx via transarterial approach (B). About 70% of the nidus was obliterated. (C) In the third treatment session, we used transvenous access by puncturing the main drainage vein. (D) A 7-Fr. angiosheath and a 12 mm x 2 cm Wanda™ Balloon Catheter (Boston Scientific, Natick, MA, USA) were introduced. A blood pressure cuff was inflated to 150 mmHg. Manual injection of contrast medium demonstrates retrograde filling of nidus. Onyx 18 was slowly injected. (E) Completion angiogram shows more than 90% obliteration of the AVM.

Direct puncture draining vein

Transarterialapproach

Wanda balloon catheter

Nidus

One main draining vein

Multiple feeding arterioles

Nidus

A B

C

D E

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Case 6 Images from a 46-year-old man with type IIb left renal AVM, and presented with gross hematuria.

(A) Pre-treatment angiogram reveals an AVM in upper pole of the left kidney, which has multiple feeding arterioles and one main drainage vein, with some smaller draining veins.(B) We performed embolization by superselection of the most prominent feeding arteriole. N-BCA mixed with lipiodol (ratio 1:2) was injected to fill the nidus and part of the drainage vein.(C) Completion angiography shows total obliteration of the largest supplying arteriole and the nidus.

n-BCADraining vein

Nidus

A B C

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Conclusion• Endovascular treatment for peripheral AVM is effective. In our series:

– Complete and nearly complete devascularization were obtained in 71% patients – Clinical improvement within three months was achieved in all cases– No major complication noted

• Angiographic classification is very useful for pre-procedural planning– Type II: transvenous or direct puncture– Type III: transvenous route is contraindicated

• Embolic agents:– Combination use of different embolic agents – Liquid embolic agents are the most frequent used type in our series

• Applied flow control if necessary – Avoid non-target embolization (eg. balloon catheter, pressure cuff)

• Adequate sedation15

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