Congenital External Carotid Artery Fistula
Case Report
Acta Cardiol Sin 2010;26:272-5
Treatment of a Rare Congenital External Carotid
Arteriovenous Fistula with Transcatheter
Coil Embolization
Meng-Hung Chi,1 Nan-Koong Wang2 and Yi-Ying Lu3
Congenital arteriovenous communications involving the external carotid artery and jugular veins are rare. We report
a 4-year-old girl with a history of an abnormal audible sound in the right ear during sleep. Physical examination
revealed a carotid bruit, thrill and a pulsatile mass in the right neck. A simple congenital right external carotid-jugular
arteriovenous fistula was confirmed and successfully treated by coil embolization. The abnormal sound and clinical
symptoms disappeared after the procedure without complications. Our report reminds readers that congenital
external carotid arteriovenous fistula is a rare disease with unique clinical manifestation and can be effectively
treated with transcatheter coil embolization.
Key Words:
Carotid arteriovenous fistula · Transcatheter coil embolization
INTRODUCTION
surgically difficult cases, transcatheter coil embolization
provides another choice of treatment.3 We report a rare
congenital right external carotid fistula presenting with
abnormal sound in the right ear, neck bruit, thrill and a
pulsatile mass. The lesion was treated successfully by
coil occlusion.
Arteriovenous fistulas (AVFs) in the head and neck
region are rare. The majority of cases involving the major vessels of the neck are of traumatic origin, either
blunt or penetrating.1 Other causes of these fistulas include ruptured aneurysms, collagen deficiency syndromes, arterial dissections, fibromuscular dysplasia,
and extensive infection of the neck.2 The most common
symptoms of carotid AVFs include bruit (83%), pulsatile
mass (67%), and pain (50%).1,3,5 Congenital AVFs between the external carotid artery and jugular vein(s) are
rare, and only a few cases have been reported in the
literature.1,3,6 Direct surgical ligation of the carotid AVF
is often curative if the site of the lesion is accessible. In
CASE REPORT
A 4-year-old previously well girl presented with an
abnormal “wind-blowing” sound in her right ear during
sleep. The noise sounded like someone closely and rhythmically blowing in her ear. The terrifying sound could
only be heard during sleep, but disappeared in the daytime. She had been suffering from this without appropriate treatment for almost a year, resulting in nightmares, insomnia and abnormal psychomotor behavior.
After a detailed physical examination, a small pulsatile
swelling, thrill, and grade IV/VI carotid bruit were
found over the right mandible angle anterior to the right
earlobe. Neurological physical examination was normal,
and laboratory investigation was unremarkable. The auditory organ survey and function test were also negative.
Received: April 8, 2010
Accepted: June 28, 2010
1
Department of Pediatrics, Hsinchu Cathay General Hospital, Hsinchu;
2
Department of Pediatrics, Cathay General Hospital, Taipei; 3Department of Radiology, Hsinchu Cathay General Hospital, Hsinchu,
Taiwan.
Address correspondence and reprint requests to: Dr. Nan-Koong
Wang, Department of Pediatrics, Cathay General Hospital, No. 280,
Sec. 4, Renai Road, Taipei, Taiwan. Tel: 886-2-2708-2121; Fax:
886-2-2709-9408; E-mail: nankoong@ms14.hinet.net
Acta Cardiol Sin 2010;26:272-5
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Congenital External Carotid Artery Fistula
There was no history of head or neck trauma.
Magnetic resonance angiography of the head and
neck revealed: (1) an engorged right common carotid
artery (CCA), engorged right external carotid artery
(ECA), and early abnormal delineation of the right external jugular vein (EJV) and right internal jugular vein
(IJV); and (2) a fistula about 0.3 cm in width connecting
the ECA to the EJV and IJV (Figure 1). Right common
carotid angiography revealed a dilated CCA, ectasia of
the ECA, and rapid opacification of the EJV and IJV
through the narrowed fistula (Figure 2A). Selective right
external carotid angiography clearly delineated a simple
short-segmental fistula in the distal portion of the ECA
that supplied the EJV and IJV (Figure 2B). The contour
of the distal ECA was smooth, and no major distal
branches near the fistula were seen. The right ECA was
engorged, with a maximum diameter of around 8 to 10
mm, but connected to a terminal fistula with a minimum
diameter of 2 to 3 mm.
Two coils (COOK Inc., Embolization Coil, MWCE
38-8-5) were carefully deployed in the distal end of the
ECA to occlude the fistula. Post-coil right ECA angiography revealed complete obliteration of the lesion without residual shunt (Figure 2C). The patient’s carotid
bruit and thrill disappeared after coil intervention. The
patient remained well with complete resolution of the
symptoms. The post-coil course was uneventful, without
any complications or recurrence for five years.
veins arise through differentiation from a common capillary plexus. During embryologic development, certain
vessels may function as arteries at one stage of embryonic life and as veins at another. If some of the connections that are normally obliterated remain patent, they
may develop into abnormal arteriovenous connections or
into some other vascular abnormality.6
The symptoms caused by carotid AVFs are mainly
dependent on the severity of the shunt. The most frequently presenting symptoms are pulsatile tinnitus, bruit
and/or thrill, ocular problems, headache, pain and a
pulsatile mass in the neck.1,3,5 A pulsatile mass beneath
the earlobe or at the mandibular angle usually presents
from birth. Cardiac failure can occur in patients, especially in newborns, depending on the size of the artery
involved, its situation to the arch of the aorta, the size of
the fistula and its duration.8 A special buzzing or ringing
noise synchronous with the pulse in the homolateral ear
may be heard, and vertigo may also occur.9,10
“Pulsatile tinnitus” describes such kind of audible
symptom produced by very high-speed shunting turbulent blood flow near the auditory organ.9,10 Such sounds
are so unusual that they are found in only 3% of all cases
of tinnitus and might be a clue to suggest a carotid AVF.9
Our patient experienced this unexplained tinnitus in her
DISCUSSION
Arteriovenous fistulas of the head and neck are quite
rare. AVFs involving the great vessels of the neck are
usually secondary to penetrating trauma, or iatrogenic
causes.2 Congenital AVFs in head and neck are relatively
rare compared to the secondary cases, and usually appear early in life. 1,4-6 A literature review revealed less
than twenty cases of congenital origin involving the external carotid artery and the jugular vein(s).6
Histopathogenesis of cervicofacial fistulas has been
studied in the forelimbs of pig and chick embryos. Persistence of embryonic communications between the primordia of arteries and those of veins originating from
identical mesenchymal tissue seems to be the basis for
congenital AVF.6 In the human fetus, both arteries and
Figure 1. Magnetic resonance angiography of the neck revealing
engorgement of the right common carotid artery (big arrow), right
external carotid artery, right external jugular vein (small arrow, EJV),
and right internal jugular vein (small arrow, IJV); and the fistula (open
arrow).
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Acta Cardiol Sin 2010;26:272-5
Meng-Hung Chi et al.
B
A
C
Figure 2. (A) Right common carotid angiogram delineating
the engorged right common carotid artery (big black arrow),
tortuous ectasia of the right external carotid artery (small
black arrow), and rapid opacification of the right external
jugular vein (small white arrow, EJV), and right internal jugular vein (white arrow, IJV) via the fistula. (B) Selective right
external carotid angiogram clearly revealing a simple narrowed segmental fistula located around the mandible angle
and remarkably prominent right external jugular vein. (C)
Post-coil right common carotid angiography revealing totally
occlusion of the congenital fistula.
edly enhances the diagnostic ability, efficacy, and accuracy in carotid AVFs.10 A delicate MRA of the surrounding anatomy and vascularities provides more detailed information about the overall vascular drainage, collateral
circulation, and possible fistula-unrelated vascular malformations.10 Powerful MRA imaging, carrying a lower
risk than traditional angiography nowadays, is the standard diagnostic tool for carotid AVFs.8-10
Symptomatic or complicated carotid AVFs such as
those causing pain, hemorrhage, pressure symptoms,
ischaemic ulceration and even congestive cardiac failure
may necessitate an attempt at surgical excision. Carotid
AVFs, if untreated, may lead to a number of well-known
complications, most importantly cardiac failure, rupture,
or emboli. In the past, treatment of choice was primary
reliant on surgical excision or ligation of the feeding
right ear during sleep for a year, resulting in insomnia.
Based on all negative findings in auditory investigation,
the girl was even diagnosed to have a psychological
problem and underwent several religious therapies. The
tinnitus was cured ultimately and she slept well after coil
embolization.
The diagnosis of a carotid AVF is usually made
without difficulty, but the vessels involved should be
precisely identified with angiography. 8 Doppler ultrasonography of the neck is invaluable, especially in the
young, for screening and follow-up, but is not as precise
as angiography. Doppler ultrasound diagnosis in our
case failed to delineate the image of the fistula, perhaps
due to the deeper location of the lesion site, limitation of
the acoustic window, and bony artifact of the ultrasound
signal. Magnetic resonance angiography (MRA) markActa Cardiol Sin 2010;26:272-5
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Congenital External Carotid Artery Fistula
carotid fistula is a safe and effective procedure. After a
detailed MRA and angiography assessment, a simple
narrowed fistula without distal collateral branches guarantees the success of coil occlusion and low risk of complications.
arteries. In a simple narrowed isthmus-like fistula without collateral circulation, transcatheter embolization may
be sufficient, safe, and effective.4,5
Detachable balloons or coil materials represent the
safest and the preferred devices for occlusion of carotid
AVFs in many reported cases.1,3-5 Aiming at abolition of
the fistula, while maintaining the patency of the remaining branches of the carotid artery, makes the detachable
balloon the preferred approach.3,4 Small-diameter coils
are useful when it is impossible to pass a balloon through the narrow orifice of the fistula, or when the venous portion of the fistula is not large enough to inflate
the balloon.3-5 Although good outcomes can be achieved,
only a certain number of suitable fistulas are amenable
to closure with coil technique.
Coil embolization of a large, high-flow carotid AVF
carries a certain risk for migration of embolic material
through the fistula and into the venous outflow. Careful
catheter manipulation, appropriate coil material selection, and precise pre-coil evaluation can prevent the risk
and later complications.4-8 Suitable candidate for traditional coil occlusion includes a single narrow drainage
site, absence of multiple fistulas, absence of large branch
vessels, appropriate size of the fistula, and safe accessibility to the lesion. Our case was a simple congenital fistula with a minimum ECA diameter of 2 to 3 mm. We
used two coils (MWCE 38-8-5) to achieve complete
abolition. Usually, the coil diameter (5 mm) must be
1.5-fold greater than the minimum diameter of feeding
artery (2 to 3 mm) to confirm the coil fixation and to
prevent dislodgement.
In summary, transcatheter coil embolization for
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