CASE REPORT

Tetralogy of Fallot with Persistent Fifth Aortic Arch:Echocardiographic Diagnosis

Gerard Holmes • Joanna L. Holmes •

William Berman Jr. • Steven Yabek

Received: 9 September 2009 / Accepted: 12 October 2009 / Published online: 10 November 2009

� Springer Science+Business Media, LLC 2009

Abstract Although persistent, fifth aortic arch (P5A) is

an uncommon anomaly. Its incidence is unknown due

largely to failure of recognition. Fundamental to its diag-

nosis is an adequate understanding of the various settings

in which P5A may manifest. One of the more frequently

reported manifestations of this unusual anomaly is a sys-

temic-to-pulmonary connection in the presence of pul-

monary atresia, with or without a ventriculoseptal defect.

This report describes a new case of P5A in an infant with

tetralogy of Fallot but not pulmonary atresia, which was

diagnosed echocardiographically. The echo-Doppler char-

acteristics of P5A in the presence of right ventricular

outflow obstruction are described, and the implications

regarding surgery for the accompanying defects are dis-

cussed. To the authors’ best knowledge, the described case

is the first reported instance of P5A in this specific setting.

Keywords Echocardiography � Persistent 5th aortic arch �Tetralogy of fallot

Persistent fifth aortic arch (P5A) was first described in 1969

as a double aortic arch lumen [9]. Since then, P5A has been

recognized in a variety of different settings, albeit in a

limited number of cases [2–7, 10]. Most diagnoses of this

condition are based on angiography or direct examination.

In one of its more frequently reported presentations,

P5A manifests as a systemic-to-pulmonary connection in

the presence of pulmonary atresia, with or without a ven-

triculoseptal defect (VSD).

We report a unique case of P5A with tetralogy of fallot

(TOF) but not pulmonary atresia, which was diag-

nosed echocardiographically. We describe the echo-

Doppler characteristics of P5A with a systemic-to-pul-

monary connection and right ventricular outflow obstruc-

tion and discuss implications regarding a surgical approach

to the accompanying cardiac defects.

Case Report

A 7-week-old girl was seen in consultation for a heart

murmur. Her birth history was unremarkable, but she had

experienced increased work of breathing and poor feeding

for a few weeks before evaluation. Physical evaluation

showed a non-dysmorphic infant with mildly increased

respiratory effort. No cyanosis, edema, or hepatomegaly

was noted. The baby’s pulses were brisk, and she had

slightly increased precordial activity without a palpable

thrill. The second sound was narrowly split and loud, and

there was a harsh medium pitch pan systolic murmur at

the mid left sternal border. No diastolic abnormalities

were noted.

A two-dimensional echo-Doppler study demonstrated

TOF with narrowing at the right ventricular os infundibu-

lum and infundibulum but a normal pulmonary valve

(Fig. 1). A tubular connection, the persistent fifth aortic

arch, was seen between the ascending aorta and the distal

main pulmonary artery just proximal to the origin of the

left pulmonary artery (Fig. 2). Diastolic flow reversal was

seen in the transverse aortic arch (Fig. 3).

Electronic supplementary material The online version of thisarticle (doi:10.1007/s00246-009-9573-4) contains supplementarymaterial, which is available to authorized users.

G. Holmes (&) � J. L. Holmes � W. Berman Jr. � S. Yabek

Pediatrix Cardiology Associates of New Mexico,

201 Cedar SE, Suite 700, Albuquerque, NM 87106, USA

e-mail: gerardhol@msn.com

123

Pediatr Cardiol (2010) 31:280–282

DOI 10.1007/s00246-009-9573-4

The baby was taken to the operating room 1 week later.

After median sternotomy, the fifth aortic arch was over-

sewn and divided. Next, a cardiopulmonary bypass (CPB)

was created, and the VSD was closed with a patch. The

infundibular muscle was resected, and a right ventricular

outflow patch was placed. The infant’s postoperative

course was unremarkable, and she returned home on the

fifth postoperative day with no medications.

Discussion

The incidence of P5A is not known due largely to a failure

of recognition [3]. Gerlis et al. [3] reviewed 2,000 speci-

mens from the combined congenital heart disease collec-

tions of the Royal Brompton and Killingbeck hospitals

(UK). They reported three covert cases of P5A from this

database misdiagnosed previously as ductus arteriosus or

aortopulmonary window and estimated an incidence of one

in 330 cases.

Four different types of connections, namely, systemic to

systemic, systemic to pulmonary, pulmonary to systemic, and

combined, have been described together with a variety of

accompanying cardiac defects in cases of P5A [8]. In addi-

tion, P5A has been reported as an isolated anomaly [8]. The

variations in connections and their accompanying defects are

summarized well by Peirone et al. [8]. An understanding of

these variations is fundamental to recognizing P5A because

the nature of the connection and the accompanying cardiac

lesion determine how it appears on images such as echocar-

diograms and how it presents clinically.

A systemic-to-pulmonary connection has been reported

in at least eight previous cases of P5A with accompanying

pulmonary atresia with or without VSD [2, 3, 5, 8]. The

reported case had a right ventricular outflow obstruction

due to infundibular stenosis but not pulmonary atresia. To

the best of our knowledge, this is the first report of P5A in

this specific setting. However, if our case is grouped with

previous cases of pulmonary atresia, it seems that P5A with

systemic-to-pulmonary connection and right ventricular

outflow obstruction generally constitutes one of the more

frequent manifestations of this relatively unusual anomaly.

The reported patient had two cardinal echo-Doppler

features with accompanying TOF. First, the persistent fifth

arch appeared as a tubular connection between the ascending

aorta and the distal main pulmonary artery just proximal to

the origin of the left pulmonary artery. Second, there was a

diastolic flow reversal in the transverse aortic arch.

The tubular nature of the connection and its position in

our patient is in contrast to an aortopulmonary window,

which is broad based and distinctly nontubular and usually

involves the proximal right pulmonary artery. It also is

distinct from a ductus arteriosus, which usually would arise

Fig. 1 Parasternal short-axis view through the cardiac base showing

a large ventriculoseptal defect (VSD), anterior malalignment of the

conal septum, and os infundibular and infundibular narrowing, but a

relatively normal pulmonary valve. See movie clip in the online

version of this article

Fig. 2 More superior angulation from the cardiac base in the

parasternal short-axis sweep showing a tubular connection between

the ascending aorta and the distal main pulmonary artery just

proximal to the left pulmonary artery origin. Color shows aortic-to-

pulmonary flow. See movie clip in the online version of this article

Fig. 3 Spectral Doppler in the distal transverse aortic arch showing

diastolic flow reversal

Pediatr Cardiol (2010) 31:280–282 281

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from the base of a subclavian or innominate artery or from

the inferior aspect of the distal aortic arch in instances of

pulmonary atresia.

Diastolic flow reversal in the transverse aortic arch is

known to occur in an aortopulmonary window and in sig-

nificant aortic valve insufficiency. It also was found in our

patient, representing runoff of blood flow from the high-

resistance systemic to the low-resistance pulmonary cir-

culations through the fifth arch. Thus, P5A also should be

considered in the differential diagnosis of TOF with P5A

diastolic flow reversal in the aortic arch, particularly when

there is right ventricular outflow obstruction.

Clinical recognition of P5A also can be important in

planning the surgical approach to repair accompanying

defects [1, 4–7]. In our patient, its recognition allowed the

surgeon first to oversew and divide the fifth arch before

creating a bypass to close the VSD, resecting the infun-

dibular musculature, and patching the right ventricular

outflow. However, if the fifth arch had been misdiagnosed

as an aortopulmonary window, the surgical approach may

have been much more complicated and risky.

Accurate diagnosis of P5A rather than an aortopulmonary

window in our patient also allowed consideration of a staged

approach. If a staged approach had been chosen, the fifth arch

would first have been ligated through a lateral thoracotomy

and the TOF repaired at a later time when the child was larger.

This approach may have been favored at other centers.

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