Truncus Arteriosus

1. Dr. Walinjom Joshua
supervisor
Pr CHELO
1

2. Persistant truncus arteriosus
Truncus Arteriosus communis
Common aortico pulmonary trunk
2

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

6. Epidemiology
risk factors:
Maternal cigarette smoking during gestation
Advanced maternal age
2q11.2 deletions (DiGeorge syndrome)
6

7. 7

8. 8

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

10. 10

11. • incomplete or failed septation of the embryonic truncus
arteriosus
• Or abnormality of conotruncal septation
11

12. Heart & great
vessels
Primitive mesoderm & neural crest cells
Give
rise
to
12

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

15. 15

16. At this period, bulbo ventricular structures rotate anteriorly and
to the right
to form the heart loop
16

17. 17

18. Trunco-conal swellings
Trunco-conal ridges
Truncal septum
Fus
e
18

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

25. 25

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

29. 29

30. Type 2
separate but proximale origins of the left and right pulmonary
arterial branches from the posterolateral aspect of the
common trunk
30

31. 31

32. Type 3
branch pulmonary arteries originate independently from the
common trunk
32

33. 33

34. Type 4
Pseudo-truncus;
TOF with pulm. Atresia with MAPCA
major aorto pulmonary collateral
arteries
34

35. 35

36. 36

37. Type A1
Identical to the type I of Collett and Edwards
37

38. 38

39. Type A2
Collett and Edwards type II and most cases of type III
39

40. 40

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

42. 42

43. Type A4
coexistence of an interrupted aortic arch
not by the pattern of origin of branch pulmonary arteries
43

44. 44

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

57. 57

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

61. Physical examination
• Cyanosis
• Signs of CCF
• Bounding peripheral pulses, wide pulse pressure
• Single S2
• Harsh systolic regurgitant murmur – VSD
• EDM – truncal valve regurgitation
61

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

65. Echocardiogram: Diagnostic.
65

66. ECG
• Normal QRS axis
• Bi-ventricular hypertrophy – 70%
66

67. CXR
• Cardiomegaly
• Pulmonary plethora
• Right aortic arch –
30%
67

68. CARDIAC CATHETERISATION
• Assess PVR in late presentations.
68

69. 69
Differential
•Large VSD
•Pulmonary atresia with VSD
•Univentricular heart

70. Medical
Surgical
• Palliative
• Defintive
70

71. 71
Treatment for TA is surgical intervention.

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.

76. Thank you
76