3. Plan
• Definition
• Epidemiology
• History
• Embryology
• Anatomy and classification
• Pathophysiology
• Presentation
• Workup
• Treatment
• Conclusion 3
4. • Congenital cyanotic cardiac defect with a
single common arterial trunk giving rise to
systemic, pulmonary and coronary circulations
proximal to brachiocephalic branches
• Associated with a large perimembranous VSD
below the truncus
4
5. Epidemiology
TA is responsible for 0.21%-0.34 % of congenital heart
defects
Incidence has been found to be 0.03-0.05/1,000 live
births.
5
9. 1798 – Wilson documents 1st case
1942 –Basic morphologic criteria - Lev
and Safir 1949 – Collet & Edwards
Classification
1962 – Ist Intracardiac repair conduit University of
Michigan
1967 – Ascending aortic allograft and valved conduit -
McGoon et al.
1971 – first conduit repair in infancy by Barratt-Boyes 9
13. Blood islands of cardiogenic
plate
Left and right endocardial tubes
Intra embryonic coelom (early
pericardial cavity)
Coalesc
e at
20
days
within
13
14. Left & right endocardial
tubes
Bulbous cordis
Fus
e at
23
days
14
19. Truncal septum divides
aorta from
Pulmonary artery and Conal
septum
Supraventricular crest and
subpulmonic infundibulum
19
20. Day
37Fusion of conal septum
with
endocardial cushions
establishes
ventricular separation
20
21. Anatomic Defects
• Single aortopulmonary trunk from base of heart
• Large perimembranous VSD (obligatory) below truncus
• Truncal valve – bi, tri or quadricuspid and often incompetent.
• Pulmonary artery arise in several patterns
• Truncal overriding equally in 60 – 80%,
to right in 10-30%,
left in 4 – 6%
21
22. • Anatomic Defects
• There is a single truncal valve with two, three,
or four leaflets. It is often incompetent,
resulting in regurgitation (backflow of blood).
• A large perimembranous ventricular septal
defect (VSD) is present directly below the
truncus in all cases. This allows for mixing of the
pulmonary and systemic venous blood and
equal pressures in both ventricles.
22
23. • The coronary arteries are frequently abnormal.
• 30% have a right aortic arch
• 33% of individuals with truncus have DiGeorge
syndrome.
23
24. • Anatomic Defects
• Truncal valve – bi, tri or quadricuspid and often incompetent.
24
26. Coronary anomalies
• Stenotic ostia,
• Single ostium
• high & low take off,
• abnormal branching & course
anterior descending from RCA & cross RV
circumflex from RCA
RCA from LAD
intramuscular course
26
27. • Right aortic arch – 30%
• Interrupted aortic arch – 10% (distal to left common carotid)
• Di George syndrome with hypocalcemia - 33%
• PFO
• OS-ASD
• Tricuspid valve lesions
• 22q11 chromosome deletion
27
28. Classification
Type 1
single pulmonary trunk from the left lateral aspect of the
common trunk,
with branching of the left and right pulmonary arteries from the
pulmonary trunk
28
41. Type A3 (hemitruncus)
• one branch pulmonary artery (usually the right) from the
common trunk
• The other branch pulmonary artery from the aortic arch (a
subtype of Collett and Edwards type III) or by systemic to
pulmonary arterial collaterals
41
45. Cyanotic al heart disease with increased pulmonary blood
flow
Fetal pulmonary blood flow less than 10%
PVR falls in early infancy improving PBF hence good
oxygen saturation
Hypoxia in this period implies pulmonary arterial narrowing
Equilibration of RV LV pressures
45
46. The physiology of TA is largely related to the
volume of blood flowing to the pulmonary circuit.
This is affected by:
1.The degree of pulmonary vascular resistance
2.The degree of truncal valvular insufficiency
3.The severity of any aortic arch abnormalities
46
47. 1. Pulmonary vascular resistance
•At birth the pulmonary vascular resistance is high
enough to prevent left-to-right shunting, which
restricts the amount of blood that can flow to the
pulmonary system.
•As this resistance drops more blood flows to the
pulmonary system, the amount of fluid overloads the
system, and heart failure begins. 47
48. Heart failure can begin within several
weeks of birth and present by
6 months of age in patients with TA.
48
49. 2 . Truncal valvular insufficiency
•The degree of regurgitation or stenosis of
the truncal valve causes additional ventricular
volume.
•The myocardium then requires greater amounts
of oxygen, which leads to coronary artery
ischemia and ventricular dysfunction.
•Together, this also contributes to the onset and
severity of heart failure. 49
50. 3. Aortic arch abnormalities
•Patients with interrupted aortic
• arches or coarctation require
•the ductus arteriosus for
• alleviating pressure overload
•in the ventricles and allowing for
• blood flow distally
50
51. • The magnitude of pulmonary blood flow (PBF) is
determined by the size of the pulmonary artery.
• If PBF is excessive, congestive heart failure
(CHF) may occur as a result of volume overload
placed on the ventricle.
• If PBF is small, the infant may appear more
cyanotic (blue) with no CHF symptoms.
51
52. • Most infants present with cyanosis or symptoms
of CHF within the first two weeks of life if not
diagnosed prenatally.
• Truncus arteriosus occurs in less than 1% of
congenital heart defects.
52
53. Cyanotic congenital heart disease with increased pulmonary
blood flow
Fetal pulmonary blood flow less than 10%
PVR falls in early infancy improving PBF hence good
oxygen saturation
Hypoxia in this period implies pulmonary arterial narrowing
Equilibration of RV LV pressures
53
54. As the PBF increases PAH
Increased pulmonary venous return
CCF
54
55. History
• Cyanosis at birth
• Early CCF
• Failure to thrive,
• Respiratory tract infections
55
56. . Cyanosis in patients with TA is due to the mixing of pulmonary
and systemic blood.
. Most patients with TA are diagnosed within one week of birth –
after pulmonary vascular resistance decreases and the ductus
arteriosus closes.
Patients present with cyanosis and respiratory distress from
pulmonary congestion and onset of heart failure.
56
58. .Some patients also present with a murmur.
.Pulmonary congestion and heart failure can manifest as:
.Poor feeding
.Lethargy
.Respiratory distress (tachypnea, subcostal retractions, nasal
flaring, grunting)
.Tachycardia
.Hyperdynamic precordium
. Hepatomegaly
58
59. Bounding peripheral pulses and a wide pulse pressure are
present.
An early diastolic murmur of truncal regurgitation may be heard.
Occasionally,
a harsh, regurgitant systolic VSD murmur may be heard along
the left sternal border.
59
60. A systolic click
may be heard at the apex and upper left sternal border and S2
is single.
If pulmonary blood flow is excessive, an apical diastolic
rumble with or without gallop rhythm may be present.
60
62. Survival
50% survival in 1 month
18% survival in 6 months
12% survival in 1 year
Modes of death
. Congestive heart failure in early life
. SBE, cerebral abscess → Eisenmenger syndrome (death in 3rd
decade)
. Adversely affected by truncal regurgitation, IAA, CoA
. Survival is favorably affected by PS
62
63. Prenatal and early postnatal diagnosis common
Proper evaluation of cyanotic infants clinches diagnosis
ABG
Pulse oximetry
ECG
CXR
TTE,
TOE
63
64. Diagnostics:
Chest X-ray: Cardiomegaly (enlarged heart) with
increased pulmonary vascular markings.
EKG: Normal QRS axis. Biventricular hypertrophy is
present in 70% of children.
Echocardiogram: Diagnostic.
64
72. 72
Patients with TA are initially medically managed to stabilize
them for surgery.
Medications include:
• Diuretics to manage volume overload
• Inotropes (e.g. dobutamine or dopamine) for cardiac
contractility,
• ACE inhibitors to reduce afterload
Ventilation
• Prostaglandin E1 is given to patients with severe aortic
coarctation to maintain patency of the ductus arteriosus.
73. 73
Surgery is usually performed within 30 days of birth.
A typical procedure:
1.Removes the pulmonary arteries from the truncus and
reattaches them to the right ventricle
2. Opens and repairs the truncus
3. Closes the VSD..
74. 74
Perioperative mortality is 10%
The risks of not intervening are so great that most patients
undergo primary surgical repair.
Long-term survival:
90% at 5 years after primary repair
85% at 10 years
83% at 15 years
75. 75
After surgery, all patients with TA are followed by pediatric
cardiologists.
Prognosis for patients with unrepaired TA is poor and
patients usually do not survive without surgical
intervention.
For patients without repair, the mean age of survival is 5
weeks and 85% do not survive to 12 months of age.
