2. Aortic arch anomalies contd..
• Aorta –Largest artery in body carrying
oxygenated blood from LV
• Grossly divided into – Root , ascending
aorta, arch and descending aorta
• Root – From aortic valve to sinotubular
jn.
• Ascending Aorta – from sinotubular
junction to origin of brachiocephalic A
• Arch – origin of br.cephalic A to Lt
subclavian A
• Descending Aorta- beyond the origin of lt
subclavian till the aortic bifurcation
4. Embryology of Aortic arch
• Aortic development begins during the 3rd week of gestation
• Complex process, which lends itself to a variety of congenital variants
and pathologic anomalies.
• Each primitive aorta consists of a ventral and a dorsal segment
• The two ventral aortae fuse to form the aortic sac, and the two dorsal
aortae fuse to form the midline descending aorta
• There are six paired arches that connect the paired dorsal and ventral
aorta.
5. Embryology of Aortic arch contd..
Development of the embryonic aortic arches and
branches.
Six pairs of primitive aortic arches develop between the
ventral and dorsal aortae.
Gray areas represent segments that normally involute.
6. Embryology of Aortic arch contd..
• The dorsal aortae also give rise
to several intersegmental
arteries.
• The primitive arches appear and
regress one after another in a
cranial-to-caudal order, and are
not all present at the same
time.
• The mature aortic arch system is
formed as some of the primitive
arches regress, whereas others
persist and develop.
7. Embryology of Aortic arch contd..
• 1st &2nd primitive arches disappear early; a remnant of the 1st arch
forms portions of the maxillary artery, and the 2nd forms portions of
the hyoid and stapedial arteries
• The primitive 3rd aortic arch ( carotid arch) -forms the common carotid
and proximal (cervical) portion of the internal carotid artery.
• The primitive 4th embryologic arches contribute to the definitive adult
aortic arch.
• The 5th primitive arches typically do not form, or they form
incompletely and then regress.
9. Embryology of Aortic arch contd..
• The primitive 6th ductus
arteriosi and central
pulmonary arteries.
• In nl dev, the proximal right
6th arch proximal portion
of the right pulmonary
artery,
• the ductal portion
degenerates, and the left
sixth arch persists as the
main and left pulmonary
arteries and left ductus
arteriosus.
10. Double aortic arch model
• Edwards proposed a theoretical
double aortic arch system with
bilateral arches and ductus
arteriosi encircling the trachea
and esophagus, which reflects the
potential contributions of nearly
all embryonic arches
• The anatomy of the normal left
aortic arch can be described by
persistence or regression of
segments of this hypothetical
double arch system.
• Most of the aortic arch anomalies
can be explained by this model
11. Normal left aortic arch
• The normal left aortic arch
regression of the distal right fourth
arch between the right subclavian
artery and the descending aorta,
including the right ductus
arteriosus, and the right dorsal
aorta distal to the origin of the
seventh intersegmental artery
12. Normal left aortic arch contd..
• The remaining proximal aspect of the
right fourth arch forms the proximal
portion of the right subclavian artery, and
the left fourth arch forms the definitive
aortic arch.
• The distal right subclavian artery a
portion of the right dorsal aorta and the
right seventh intersegmental artery.
• Left subclavian artery entirely from the
left seventh intersegmental artery.
13. Normal left aortic arch contd..
• The ductus arteriosus, either patent or
ligamentous, is usually present on the left,
connecting the proximal left pulmonary
artery to the aorta distal to the origin of
the left subclavian artery.
• The normal left arch crosses the left main
bronchus at the level of the T5 vertebral
body. The descending thoracic aorta is
typically to the left of the midline.
14. Normal left aortic arch contd..
• first branch arising from the normal left arch the right
brachiocephalic (innominate) artery, f/b the left common carotid and
left subclavian arteries
• This left arch with 3vessel branching seen in 70-80%
15. Common variants
➢Bovine type arch - the left
common carotid artery has a
common origin with, or, less
commonly, arises directly from,
the right brachiocephalic artery
➢Usually asymptomatic
➢Sometimes, with aberrant rt
subclav.A Can cause
dysphagia lusoria
16. Bovine aortic arch contd..
Oblique C+ CT image-
Common origin of brachiocephalic trunk and left
common carotid artery = bovine arch.
17. Common variants –Lt aortic arch contd..
➢Lt vertebral artery arising
directly from the aortic arch
proximal to the left
subclavian artery, ( 5%–6%),
and is often hypoplastic
➢LCCA & LSCA form a left
sided brachiocephalic trunk
(1 to 2%)
Origin of left vertebral artery from aortic arch b/n
LCCA and LSCA
18. Congenital anomalies of aortic arch
➢Left aortic arch with aberrant Rt subclavian artery
• MC congenital anomaly of the aortic arch
• Prevalence - 0.5%–2%
• Embryology -: results from regression of the right arch (b/n the rt
common carotid and right subclavian arteries) including the right
ductus arteriosus
• The distal right dorsal aorta (rather than the right fourth arch)
becomes the proximal right subclavian artery, forming its
retroesophageal portion.
• Since the right ductus regresses a vascular ring does not develop.
19. L aortic arch with aberrant Rt subclv A contd..
regression of the right arch between the right common carotid
and right subclavian arteries, including the right ductus
arteriosus (gray). The first branch arising from the arch is the
right common carotid artery, followed by the left common
carotid artery, left subclavian artery, and finally the aberrant
right subclavian artery, in that order.
20. L aortic arch with aberrant Rt subclv A contd..
• The aberrant right subclavian
artery is the last arch branch, and
has an oblique retroesophageal
course from caudal left to cranial
right.
• Usually isolated
• Uncommon associations- aortic
coarctation, PDA ,VSD and carotid
or vertebral artery anomalies
,Trisomy 21 ( 35%)
Axial CT angiographic image shows the left-sided aortic arch (blue
arrow), and the aberrant right subclavian artery passing posterior
to the esophagus
21. L aortic arch with aberrant Rt subclv A contd..
• Course –
• a) behind esophagus ( 80%)
• b) between esophagus + trachea (15%)
• c) anterior to trachea(5%)
• Usually asymptomatic
22. L aortic arch with aberrant Rt subclv A contd..
• 10% of adults – symptomatic - dysphagia resulting from extrinsic
compression of the esophagus due to the retroesophageal course of
the aberrant right subclavian artery dysphagia lusoria
• A loose vascular ring may be formed in the setting of a left arch when
the aberrant right subclavian artery arises from a diverticulum of
Kommerell, that is completed by the right-sided ductus arteriosus
23. L aortic arch with aberrant Rt subclv A contd..
• Kommerell diverticulum -
remnant of the dorsal aortic
arch.
• The presence of this diverticulum
is thought to be related to
persistence of the right sixth
arch component that forms a
right-sided ductus arteriosus.
Oblique axial images (A,B) and volume rendered images (C,D) -a left-sided aortic arch with a Kommerell’s diverticulum (*)
giving origin to the aberrant right subclavian artery (arrowhead) .Significant stenosis (dotted arrow) was noted at the site
of insertion of right arterial duct into the right pulmonary artery.
24. Imaging -
• CXR - Oblique shadow
above aortic arch on
frontal film.
25. L aortic arch with aberrant Rt subclv A contd..
• Barium swallow –
• The aberrant vessel passes
obliquely upwards and to the
right, posterior to the
esophagus, causing a posterior
indentation on it. If the vessel is
dilated at this point it will make
a wide indentation- bayonet
deformity
26. L aortic arch with aberrant Rt subclv A contd..
Axial CECT image –right aberrant subclavian A causing
compression over esophagus
27. ➢Left circumflex aorta
• a left aortic arch with right descending aorta and a right ductus
arteriosus
• Arch branching pattern - similar to that of a left arch with
retroesophageal aberrant right subclavian artery, here, the arch itself
crosses the midline posterior to the esophagus, rather than the
aberrant right subclavian artery .
• right ductus arteriosus or ligamentum arteriosum connects the right
pulmonary artery to the descending aorta, forming a vascular ring.
28. • extremely rare - results from regression of the right fourth arch
between the right common carotid and right subclavian arteries, with
persistence of the right-sided sixth arch component forming the
ductus arteriosus
• Aortic knob is visualized on Lt side but descending aorta cast a shadow
along right side of spine.
29. • Barium swallow –
• Barium filled esophagus is indented from behind by circumflex AA.
• The indentation is large & has a descending course towards right.
30. • Right aortic arch
• Rare aortic anomaly with a reported incidence of 0.1%
• 3 main subtypes
• Type 1- RAA with mirror image branching
• Type 2 -AA with aberrant left subclavian artery ( M/C )
• Type 3- RAA with isolated subclavian artery.
• Other rare subtypes include RAA with isolation of innominate artery
and right circumflex aorta.
31. Right aortic arch contd..
• Right of trachea & esophagus , over
right mainstem bronchus.
• Descending aorta – Rt.
• Crosses lower thoracic spine -
passes through left hemidiaphragm.
• The ductus is attached to the Lt
innominate artery anterior to the
esophagus
32. Right aortic arch contd..
• RAA with mirror image
branching – Type 1
• results from regression of the
left dorsal aorta distal to the
origin of the seventh
intersegmental artery
• So that the left fourth arch
becomes the proximal
subclavian artery rather than
the definitive aortic arch
33. RAA with mirror image contd..
• Branches in order:
• Left innominate A , RT CCA ,RT
SA, Descending aorta is on right
• Associations -cyanotic
congenital heart disease which
includes
• tetralogy of Fallot
• truncus arteriosus
• tricuspid atresia
• transposition of the great
arteries
34. • CXR:
• Rt aortic arch indents trachea.
• Trachea may be slightly deviated to the left.
• Descending aorta is on the right.
35. • Barium swallow:
• Indentation on the Rt of esophagus.
• Posterior indentation Retroesophageal aortic diverticulum & Lt
ductus.
36. • Type II—RAA with aberrant left
subclavian artery
• most common subtype of RAA
• due to the abnormal involution
of left fourth arch in between
the left subclavian and left
common carotid artery.
• Branches in order - right
common carotid, right
subclavian artery, left common
carotid, and the left subclavian
artery (takes a retroesophageal
course to reach on the left side)
37. RAA with aberrant left subclavian artery contd..
• Bulbous configuration of origin of LSA -Retroesophageal aortic diverticulum of
KOMMERELL
• second most common cause of a vascular ring after a double aortic arch
38. • vascular ring is formed by the
ductus which joins the lt
pulmonary artery to the lt
subclavian.
• Usually a loose ring and
asymptomatic.
• Occasionally cause significant
compression when connected
posteriorly to a diverticulum.
39. • CXR-
• Impression on trachael air shadow
by right aortic arch.
• Descending aorta on right side.
• Trachea is bowed forward by the
aberrant left subclavian artery
which passes behind it.
40.
41. • Barium swallow
• Right esophageal
indentation by right aortic
arch.
• Impression on left side of
esophagus simulating a
double aortic arch.
42.
43. • Right Arch with Isolation of the Left Subclavian Artery
• 3rd most common right aortic arch anomaly
• Embryology: interruption of embryonic left arch between
• left CCA & left subclavian artery
• left ductus & descending aorta
• resulting in a connection of left subclavian artery with left pulmonary artery
through the ductus.
• Isolation of subclavian always occurs on the side opposite the AA.
• patients have features of subclavian steal syndrome
45. • Associations - truncus arteriosus, tricuspid atresia or tetralogy of
Fallot
• Ductus may be patent / atretic
• Ductus patent Lt to Rt shunt.
• If pulmonary pressure is elevated Rt to Lt shunt.
46. • ANGIOGRAPHY:
• Aortography demonstrate prompt opacification , except the isolated
SA .The artery opacifies late through collateral arteries , primarily
from vertebral artery.
• If ductus is patent blood flow occurs from isolated SA into the PA due
to lower pulmonary resistance.
• Pulmonary Artery opacifies from a subclavian arteriogram.
47.
48. RAA with aberrant left brachiocephalic artery
• Isolation of both left CCA &
left subclavian.
• Due to regression of left
arch proximal to left carotid
& distal to left subclavian
49. • RAA with Lt Descending aorta
• Circumflex arch.
• Aorta passing over right bronchus , crosses immediately to left behind
esophagus to form a left descending aorta.
• Rt circumflex aorta > lt circumflex
• Embryology - the persistence of the left sided dorsal aorta leading to
descending thoracic aorta coursing on the left side
• The closest differential - double aortic arch with an atretic left arch
segment
51. • Bi truncus arch
• Only two great vessels arise
from AA.
• Aberrant rt subclavian artery
arises from a common trunk
with Lt subclavian.
• Compression of trachea by
bicarotid truncus in front &
bisubclavian truncus behind
cause stridor.
52. • Cervical aortic arch
• aortic arch is seen at an abnormally
high position reaching at or just
above the level of clavicles
• presumed to be arising either from
persistence of the second or third
branchial arches with regression of
the normal fourth arch/ from failure
of the caudal migration of the
normally developing fourth arch
53. cervical aortic arch contd..
• cervical aortic arch complex –
• high position of aortic arch in the superior mediastinum,
• separate origin of contralateral carotid arteries,
• presence of aberrant contralateral subclavian artery from the
aortic diverticulum
• retroesophageal descending aorta coursing contralateral to the
side of the aortic arch
• The clinical presentation - a pulsatile neck mass.
55. cervical aortic arch contd..
• CXR -the high-riding arch may be seen as a mass-like paratracheal soft
tissue density
• normal aortic knob may be absent
• widened mediastinum
• compression and displacement of the trachea and oesophagus may be
demonstrated
56.
57. • Interruption of aortic arch
• The presence of complete aortic
luminal discontinuity between
ascending and descending aorta is
termed as interruption of the aortic
arch.
• a remnant fibrous cord +/-
• Regression of both Rt & Lt aortic
arches
• Descending aorta is supplied by PDA
or collaterals if ductus is closed
58. Interruption of aortic arch contd..
• 3 Types
Type A : it is characterized by the level of interruption distal to the left
subclavian artery. MC in adults
Type B : the level of discontinuity is between left common carotid and
left subclavian artery. MC in infants
Type C : it involves luminal interruption between right brachiocephalic
and left common carotid artery
60. Interruption of aortic arch contd..
• Associations -:
• PDA
• VSD
• ASD
• Truncus arteriosus
• Combination of VSD , subaortic stenosis & interruption of AA – Becu
complex
61. Interruption of aortic arch contd..
❑Clinical features:
• Cyanosis & CCF.
• Bounding pulses in the carotid with
weak pulses else where.
❑Radiological features:
• Pulmonary over circulation.
• Enlarged Rt heart.
• Absence of normal aortic impression
on esophagus.
62. • Double aortic arch
• the right and the left fourth branchial arches persist leading to the so
called double aortic arch, each one to be seen on either side of
trachea
• The common carotid and subclavian artery arises from the ipsilateral
arches on both sides
• This arrangement encircles the trachea and esophagus completely
and is the most common cause of complete vascular ring
63. • The ductus is usually on the left side and is seen ipsilateral to the side
of atretic arch .
• Similarly, the descending thoracic aorta is contralateral to the side of
dominant arch.
• The two aortic arches can be of the same caliber, or else one of the
arches may be atretic or hypoplastic.
• Most commonly, the right arch is dominant and is more cranial as
compared to the left
• Clinically, the infants present early in life with barky cough and
respiratory stridor.
64.
65. • The length of DA affects the degree of compression.
• In a minority of cases part of the arch, usually the left side, is atretic,
persisting as a fibrous remnant which completes the ring.
• There may be a suggestion of tethering at the site of the atresia
66. • Four subtypes based on segmental atresia of left arch:
• atresia occurs between Lt Ductus & descending aorta.
• atresia between Lt subclavian & Lt Ductus.
• atresia between Lt CAA & Lt subclavian
• atresia between ascending A & Lt CCA
68. • Chest x ray:
• Bilateral aortic arches indenting
the trachea.
• Rt usually larger & higher,
occurring at or above the azygos
vein.
• Trachea is not shifted to either
side because it is fixed between
two arches.
69. • Aortic knuckle tends to be inconspicuous as
each individual double arch is smaller than a
normal single arch .
• Lateral trachea may be indented
posteriorly & compressed.
• No abnormality may be seen in infants due
to prominent thymic tissue.
• Clue : slight indentation of trachea on the rt
& a rt descending aorta.
70. • OESOPHAGOGRAM:
• Bilateral esophageal
indentation with a reversed S
- shaped configuration ( right
indentation higher than left )
– most diagnostic feature.
71. • Broad horizontal posterior
indentation at the level of 3rd
or 4th thoracic vertebra ( by
right arch crossing posteriorly
to join left arch)
• Aberrant subclavian with
diverticulum – D/D
72. • CT scan
“4 artery sign” 2 subclavian
+ 2 carotid arteries evenly
spaced around trachea on
section cephalad to aortic
arch.
73.
74. • Hemitruncus
• Ectopic origin of Rt or Lt pulmonary
artery from the aorta.
• Faulty septation of the truncus à
6th arch gets incorperated into the
aorta.
• Anomalous Rt pulmonary A more
common.
• Associations PDA, APW, TOF.
• C/F Respiratory distress, CCF,
cyanosis.
75. Hemitruncus
• CXR:
• Pulmonary over circulation More severe on the ectopic side.
• Lobar emphysema à Compression by enlarged pulmonary A.
• PERFUSION SCAN:
• Paradoxical absence of uptake in the over perfused lung.
• ANGIOGRAPHY:
• Only one pulmonary A can be entered through the RV.
76.
77. • Coarctation of aorta
• Congenital aortic narrowing at the
region of isthmus.
• 5% of congenital heart disease.
• 80% are males.
• Associations:
• Turners syndrome
• Bicuspid aortic valve.
• Cerebral aneurysms.
78. • Pre-ductal coarctation:
• Distal aorta well perfused by the ductus
in utero No collaterals Post natal
closure of duct Heart failure.
• Post-ductal coarctation
• In utero formation of collaterals
,Asymptomatic in neonates.
79. Coarctation of aorta contd..
• Figure of 3 aortic aortic knob:
• Enlarged subclavian above the coarctation.
• Pinching at the site of coarctation.
• Post-ductal dilatation.
• Low knucle à Prominent distal aorta.
• DA displaced to the left.
• Prominent ascending aorta.
• cardiomegaly
80. Coarctation of aorta contd..
• Rib notching Bilateral, asymetrical.
• Inferior aspect of posterior 1/3rd.
• Spares 1st & 2nd ribs.
• Shallow/deep – well corticated margins.
82. • CTA/MRA/DSA
• are capable of delineating the
coarctation & collateral vessels,
• most common collateral pathway
being subclavian artery to
internal mammary artery to
intercostal arteries (resulting in
inferior rib notching) to post-
coarctation part of descending
thoracic aorta
83. • Pseudo coarctation
• Rare anomaly characterized by kinking or buckling of the descending
aorta at the level of the ligamentum arteriosum
• There is no significant hemodynamic obstruction or pressure gradient
across the lesion (<25 mm Hg), and therefore no collateral vessel
formation
• Pseudocoarctation is usually asymptomatic and is generally
considered to be a benign entity that does not require surgical
intervention
84. Pseudo coarctation contd..
Elongation of the descending aorta, with a
buckling at the level of the ligamentum
arteriosum, distal to the origin of the left
subclavian artery.
85. Prenatal assessment
• Recognition of the trachea, three major vessels, ductus arteriosus and
descending aorta in the axial views of the upper mediastinum is
necessary for a complete fetal cardiac assessment.
• Meticulous attention to anatomic landmarks will lead to successful
prenatal diagnosis of important vascular rings making early postnatal
management possible.
86. Prenatal assessment contd..
• Clues to aortic arch anomalies include:
• Abnormal position of the descending aorta.
• Absence of the normal ‘V’-shaped confluence of the ductal and aortic
arch.
• Gap between the ascending aorta and main pulmonary artery in the
three-vessel view.
• Abnormal vessel behind the trachea with or without a vascular loop or
ring around the trachea
