1. D-TGA
DR.VINOD.G.V

2. TRANSPOSITION
Abnormal origin of the Aorta and Pulmonary Artery from the ventricular complex
Atrioventricular concordance with ventriculo-arterial discordance
Abnormal spatial relationship of the great arteries
Results in two circulations in parallel

3. Incidence & Prevalence
5% to 7% of all congenital cardiac malformations
The incidence is reported to range from 20.1 to 30.5/100,000 live births
strong (60%–70%) male preponderance

4. Embryology

5. Trunco conal malseptation Hypothesis
Normally related great arteries result from spiral downgrowth of the truncoconal septum, whereas TGA results from straight downgrowth of the trunco conal septum.

6. The embryonic Aortic switch procedure

7. During development of the conotruncal region, the pulmonary artery is related
to the left conus and the aorta to the right conus

8. normal movement of the pulmonary valve proceeds from posterior to anterior on the left side in the interval between 30 and 34 days of age and is related to normal development of the subpulmonary infundibulum

9. During this same interval, the aortic valve remains stationary, apparently because of the normal lack of development (or absorption) of the subaortic infundibulum

10. abnormal growth and development of the subaortic infundibulum and the absence of growth of the subpulmonary infundibulum.
The aortic valve is protruded superiorly and anteriorly by the development of the subaortic infundibulum, placing it above the anterior right ventricle .
Failure of development of the subpulmonary infundibulum prevents the normal morphogenetic movement of the pulmonary valve from posterior to anterior and further results in abnormal pulmonary to mitral valve ring fibrous continuity

12. Anatomy
The common clinical type - situs solitus of the atria, concordant AV and discordant ventriculoarterial alignments - complete TGA.
TGA {S,D,D} - TGA with situs solitus (S) of the atria and viscera, usual (D) looping of the ventricles and an anterior and rightward (D) aorta.

14. Great artery relationship
Situs solitus and intact ventricular septum - the aortic root is directly anterior or anterior and to the right of the pulmonary trunk in a slightly oblique relationship
Less commonly, the aorta may be positioned anterior and to the left or, rarely, posterior and to the right of the pulmonary trunk.

16. Coronary Anatomy
The two aortic sinuses of Valsalva adjacent to the aorticopulmonary septum that “face” the pulmonary artery contain the ostia of the coronary arteries in more than 99% of cases

17. Coronary anatomy Usual-66.9 CX from RCA-16.1 Single RCA-3.9
Single LCA-1.7
Inverted-2.4
Intramural LCA-2.1
Other-1.6

19. SA node artery
Origin and proximal course of artery may be variable; reaches the sinus node by the interatrial groove on the anterior surface of the heart, occasionally with an intramyocardial course in the anterosuperior rim of the fossa ovalis.
can be damaged easily during balloon atrial septostomy, during surgical septectomy or when this portion of the septum is widely excised as in the Mustard or Senning atrial switch operation.

20. Coexisting Anomalies
Nearly half of the hearts have no other anomaly except a PFO or a PDA.
The VSD is the most frequent coexisting anomaly-40% to 45%.
- perimembranous (33%)
- inlet septum( 5%)
- muscular (27%)
- malalignment (30%)
- conal septal hypoplasia type (5%)

21. Malalignment VSD
anterior malalignment of the infundibular septum is frequently associated with sub aortic stenosis, aortic arch hypoplasia, coarctation ,complete interruption of the aortic arch
Posterior (leftward) malalignment is associated with varying degrees of LVOTO–subpulmonary stenosis, annular hypoplasia or even pulmonary valvar atresia

22. Subpulmonary Stenosis (25%)
Fixed
-Circumferrential fibrous membrane /diaphragm
- Fibromuscular ridge
- Herniating tricuspid leaflet tissue
- Anomalous MV septal attachments
- Tissue tags from membranous septum
Dynamic-associated with SAM

23. Subaortic Obstruction
Rightward and anterior displacement of the infundibular septum
Associated aortic arch anomalies
- hypoplasia
- coarctation
- interruption
Asso. RV hypoplasia & tricuspid valve anomalies

24. TV anomalies Straddling/overriding of chordae
Overriding of the tricuspid annulus
Abnormal chordal attatchments
Dysplasia
Accessory tissue
Double orifice

25. MV anomalies Nearly 20% Functionally imp 4%
Cleft anterior mitral valve leaflet
anomalous papillary muscles and chordae
Straddling
redundant tissue tags

26. Juxtaposition of atrial appendages
Both appendages or left + part of right are adjacent
2-6%
Left > right -6x
Female preponderance
often additionally associated with major cardiac pathology, including dextrocardia, VSD, bilateral infundibulum, right ventricular hypoplasia and tricuspid stenosis or atresia.

27. HAEMODYNAMICS

28. Fetal and Post natal physiology

29. Fetal circulation

30. Fetal circulation in TGA

31. TGA with VSD
in Fetus

32. TGA +VSD+PS
IN FETUS

33. POSTNATAL PHYSIOLOGY OF TGA

34. Determinants of effective gas exchange
Effective ventilation
Effective Pulmonary circulation
Pulmonary blood flow
Pulmonary vascular resistance
Existence of a communication between pulmonary and systemic circuits
Persistent fetal channel – PFO or DA
Abnormal channels – ASD, VSD
Effective delivery of oxygenated blood to the tissues

35. Definition of shunts Anatomical shunts
Left to Right: Blood flowing from left sided chambers to the right sided chambers
Right to Left: Blood flowing from right sided chambers to the left sided chambers

36. Definition of shunts Physiological shunts
Left to right: The volume of oxygenated pulmonary venous return recirculated to pulmonary circulation (Qp – Qep)
Right to left shunt: The volume of systemic venous return that contributes to cardiac output (reentering the systemic circulation) without having passed through the pulmonary circulation (Qs – Qep)

37. Definition of shunts Effective pulmonary blood flow (Qep):
The volume of systemic venous return that is effectively oxygenated in the lungs
Effective systemic blood flow (Qes):
The volume of oxygenated pulmonary venous return that enters the systemic circulation and perfuses the systemic capillary bed

38. RIGHT HEART LEFT HEART Systemic venous Pulmonary venous return return
Anat R-L
Anat L-R
RIGHT
HEART
LEFT
HEART
Physio R-L
Physio L-R
LUNGS
BODY

39. Right to Left Shunt
Systole
VSD
Left to Right Shunt
Diastole

40. TGA: Atrial and Ventricular level shunts
From LA to RA / LV to RV
Anatomically left to right
Physiologically, this volume of oxygenated blood enters systemic circulation. Hence, they contribute to Qes

41. TGA: Atrial and Ventricular level shunts
From RA to LA/ RV to LV
Anatomically, right to left shunt
Physiologically, this volume of systemic venous blood enters pulmonary circulation. Hence they contribute to Qep

42. TGA: Shunt at PDA level Aorta to PA flow:
Anatomically it is left to right
Here the deoxygenated systemic venous blood enters pulmonary circulation. Hence, this volume contributes to Qep
PA to Aorta flow:
Anatomically it is right to left
Here the oxygenated blood enters systemic circulation. Hence, this volume contributes to Qes
Thus, the flow across the ductus is functionally opposite to that of flow across ASD or VSD in TGA

43. PDA Initially, bidirectional flow across the ductus
Later, once the PVR falls, the flow essentially becomes aorta to PA
The pulmonary circulation becomes overloaded fast, especially if the PFO is restrictive

44. Unique feature
Net inter-circulatory mixing volume is constant: net R-L, L-R, Qep and Qes are equal to each other
Any major difference in the volumes would result in depletion of blood volume of one circulation at the expense of overloading the other circulation

45. Precise factors controlling intercirculatory exchange
SPECULATIVE, MULTIPLE
LOCAL PRESSURE GRADIENTS
Compliance of the cardiac chambers
Phase of respiratory cycle
Vascular resistances
Heart rate
Volume of blood flow

46. Flow across the communications “Rules of the Heart”
With only ASD, the flow has to be bidirectional
If the flow is only or predominantly left to right across the ASD, it suggests presence of additional shunt (VSD or PDA)
Unrestrictive VSD - flow is bidirectional
Except in the initial few days, PDA flow is always left to right (Ao to PA).
Presence of right to left flow across ductus may suggest the presence of coarctation of aorta

47. Factors influencing systemic saturation
Extent of inter-circulatory mixing and Total pulmonary blood flow
High PBF results in increased oxygenated blood available in the left sided chambers for mixing: higher systemic SO2 if there is good mixing
Reduced PBF will result in low systemic SO2 in spite of adequate anatomic shunts

48. Factors influencing systemic saturation
If there is delay in the fall of PVR (PPHN), hypoxemia will persist despite adequate ASD
Need ECMO or urgent ASO
Hypoxemia provokes a fall in SVR and increase the recirculating systemic volume
Fall in SVR may deplete the pulmonary circulation further

49. Role of bronchopulmonary collaterals
Systemic arterial hypoxemia may stimulate development of bronchpulmonary collaterals
Usually in TGA with solely a restrictive inter-atrial communication
Prolonged survival of such infants may be due to this extra-cardiac site of shunting/mixing

50. History M:F – 4:1;unless juxtaposition of atrial appendages
Usually in multigravida-2X increase in > 3 pregnancies
Familial recurrence-monogenic inheritance

51. CLINICAL MANIFESTATIONS

52. TGA PHYSIOLOGIC CLINICAL CLASSIFICATION
1. TGA (IVS OR SMALL VSD) with increased PBF and small ICS 2. TGA (VSD large) with increased PBF and large ICS 3. TGA(VSD and LVOTO), with restricted PBF 4. TGA(VSD and PVOD),with restricted PBF

53. Cyanosis As early as day 1 in pts with IVS(1st hr-56%;1st day-90%)
More intense if associated PS/atresia
Mild if associated non restrictive VSD
PS often responsible for hypercyanotic spells-intense cyanosis, tachypnea, extreme irritability and hypothermia
Squatting is rare
Reverse differrential cyanosis

54. CHF In patients with a large PDA
Large VSD – CHF develops within 1-3 wks

55. Mortality 1st week-30% 1st month-50% 1st year-90%
Depends on the degree of shunting
Moderate PS improves survival
Predilection for brain abscess but rare < 2 years

56. Arterial Pulse Bounding pulse
- due to large volume of highly unsaturated blood
- Not due to PDA-since only systolic shunt from aorta to PA
Diminished femoral pulses
- CoA
- Subaortic stenosis-anterior and rightward displacement of septum

57. Palpation Normal in neonates RV impulse
LV impulse – non restrictive VSD with low PVR
Palpable S2 A2

58. Auscultation
Loud A2
LV S3-mildly cyanosed patients,increased PBF,LV failure
RV S3-deeply cyanosed patients, increased systemic flow, RV failure

59. Auscultation
Ejection click-pulmonary;does not decrease with inspiration
Aortic-subaortic stenosisdilated aortic root
MSM-aortic:hypervolemic and hyperkinetic circulation
Pulmonary: valvular- after few weeks of birth, progressively increases
Subvalvular dynamic obstruction-3rd LICS and radiates to the right

60. Auscultation VSD: holosystolicshortensabolished PDA:
Systolic if large PDA since high PVR curtails diastolic flow
Continuous if restrictive PDA
MDM may be heard across AV valves

61. ECG Normal in first few days of life
RAE-increased pressure(CHF) or volume (hypervolemic systemic circulation)
LAE-large ASD,increased PBF

62. ECG RVH - NR VSD + high PVR/PS BVH - NR VSD + low PVR
Right precordial T waves not inverted but rather distinctly taller than the left sided T waves

64. CXR Absent thymic shadow after 12 hours of life
Narrow vascular pedicle - AP orientation of great vessels
Right aoric arch %
Egg on side appearance
Juxtaposition-localised bulge along the mid left cardiac border which represents contiguous mass of the 2 appendages together
PBF & Heart size inversely proportional

65. D-TGA with VSD

66. ECHO

67. Diagnosis
Detection of shunt
Detection of outflow obstructions
Associated anomalies
Coronary Anatomy

68. Parasternal long axis view showing the 2 great vessels parallel to each other.  In a normal heart, the 2 great vessels should not appear together in any plane as they cross each other in their proximal course.  The aorta here is anterior, not posterior as it normally should be.

69. Parasternal short axis view showing the aortic valve anterior to the pulmonary valve. .

70. Parasternal long axis with a tilt of the probe to show the entire length of the abnormally situated anterior aorta.  The posteriorly situated pulmonary artery can be seen to bifurcate, a clue that the posterior vessel is not an aorta.

71. Subcostal view showing the pulmonary artery coming from the left ventricle and bifurcating as it travels distally.

74. Cardiac catheterization in TGA

75. Fallacies in application of Fick’s Principle in calculating shunts and flows in TGA
Oxygen consumption is not normal, so assumed values are unreliable
Arteriovenous oxygen differences may be very small, so magnitudes of errors in calculated values would be very large.
Effect / contribution of Bronchopulmonary collaterals to PBF – can result in overestimation.

77. TGA WITH NO ASSOCIATED
DEFECTS IN NEWBORN

78. TGA WITH LARGE VSD IN
NEWBORN

83. Management

84. Medical
Prostaglandin E1 infusion should be started to improve arterial oxygen saturation by reopening the ductus. This should be continued throughout the cardiac catheterization and until the time of surgery.
Oxygen should be administered for severe hypoxia. Oxygen may help lower pulmonary vascular resistance and increase PBF, resulting in increased systemic arterial oxygen saturation.

85. Role of PGE1 in TGA
Considerable benefit in first few days till PVR is elevated, especially if PFO is small
Enables bidirectional shunting, improves mixing
If valve of FO is competent, it would result in increased LA pressure and pulmonary edema

86. Atrial Septostomy
Before surgery, cardiac catheterization and a balloon atrial septostomy (i.e., the Rashkind procedure) are often carried out to have some flexibility in planning surgery.
a balloon-tipped catheter is advanced into the left atrium (LA) through the PFO. The balloon is inflated with diluted radiopaque dye and abruptly with-drawn to the right atrium (RA) under fluoroscopic or echo monitoring.

87. Atrial Septostomy
For older infants and those for whom the initial balloon atrial septostomy was only temporarily successful, blade atrial septostomy may be performed.
Following this, the balloon procedure can be repeated for a better result.

88. Definitive Repair At three levels:
the atrial level : Senning or Mustard Sx
ventricular level : Rastelli operation
great artery level : arterial switch operation or Jatene operation

89. Atrial level Surgery
Mustard operation: This oldest surgical technique redirects the pulmonary and systemic venous return at the atrial level by using either a pericardial or a prosthetic baffle.

90. Senning operation: This is a modification of the Mustard operation
Senning operation: This is a modification of the Mustard operation. It uses the atrial septal flap and the RA free wall to redirect the pulmonary and systemic venous return

91. Complications
a.Obstruction to the pulmonary venous return (<5% of all cases)
b.Obstruction to the systemic venous return (<5% of all cases)
c.Residual intra-atrial baffle shunt (=20% of all cases)
d.Tricuspid valve regurgitation (rare)

92. e.Absence of sinus rhythm (>50% of all cases) and frequent supraventricular arrhythmias
f.Depressed RV (i.e., systemic ventricular) function during exercise
g.Sudden death attributable to arrhythmias (3% of survivors)
h.Pulmonary vascular obstructive disease

93. Arterial switch operation (or Jatene operation)

96. Pre requisite
An LV that can support the systemic circulation after surgery
The LV pressure should be near systemic levels at the time of surgery, or the switch should be performed shortly after birth (i.e., before 2 weeks of age).
In patients whose LV pressure is low, it can be raised by PA banding, either with or without a shunt, for 7 to 10 days (in cases of a rapid, two-stage switch operation) or for 5 to 9 months before undertaking the switch operation.
LV pressure >85% and LV posterior wall thickness >4.5 mm appear to be satisfactory.

97. Pre-op
Coronary artery pattern amenable to transfer to the neoaorta without distortion or kinking.
Risk is high when the left main or LAD coronary artery passes anteriorly between the aorta and the PA.

98. Pre-op
The left ventricular inflow and outflow tracts must be free of significant structural abnormality.
The right ventricular outflow tract should be free of significant stenosis.
Mild pulmonary valve stenosis or dynamic or surgically remediable subpulmonary stenosis does not preclude a successful arterial switch operation. Patients with subaortic stenosis in association with a large VSD may receive the Damus-Kaye-Stansel operation

99. Anatomic variants that may impact operative mortality include
An intramural course of a coronary artery
A retropulmonary course of the left coronary artery
Multiple VSDs
Coexisting abnormalities of the aortic
Straddling AV valves
Longer duration of global myocardial ischemic (cross-clamp)
prolonged circulatory arrest times

100. Complications PA stenosis at the site of reconstruction - 5% to 10%
complete heart block - 5% to 10%.
Aortic regurgitation (AR)
late complication > 20% of patients especially PA banding
An important cause of AR may be unequal size of the pulmonary cusps that leads to eccentric coaptation
Coronary artery obstruction
myocardial ischemia, infarction, and even death.

101. Rastelli operation In patients with VSD and severe PS
The LV is directed to the aorta by creating an intraventricular tunnel between the VSD and the aortic valve.
A conduit is placed between the RV and the PA

102. Rastelli operation

103. Complications
conduit obstruction (especially in those containing porcine heterograft valves)
complete heart block (rarely occurs).
This conduit needs to be replaced as the child grows.

104. Pulmonary Artery Banding
Transposition associated with large VSD without LVOTO To prevent Heart failure Pulmonary vascular disease Present Indications Presence of complex/multiple VSDs Coexisting medical conditions that cause a delay in surgery To train LV before switch in TGA/IVS

106. THANK U

107. MCQ

108. 1. In a neonate with TGA false statement a
1.In a neonate with TGA false statement a.Ductal closure can precipitate severe desaturation b.The pulmonary and systemic circulations are arranged in series c.It may be necessary to create an ASD d.Immediate complete surgical repair is usually indicated

109. 2. Most common coronary anomaly in TGA a. Single LAD b. Single RCA c
2.Most common coronary anomaly in TGA a.Single LAD b.Single RCA c.LCX from RCA d.Intramural LAD

110. 3. Reverse differential cyanosis a. TGA with PDA+ high PVR b
3.Reverse differential cyanosis a.TGA with PDA+ high PVR b.PDA with reversal c.L TGA with reversal d.TGA+VSD+PS+PDA

111. 4. Wrong statement in TGA a. TGA babies are predominantly males b
4.Wrong statement in TGA a.TGA babies are predominantly males b.Maternal diabetes may be associated c.Birth weight are normal d.Extracardiac anomalies are frequent

112. 5. Surgical procedure of choice for a neonate with complete TGA a
5.Surgical procedure of choice for a neonate with complete TGA a.Atrial switch surgery b.Arterial switch surgery c.Rastelli operation d.Fontan operation

113. 6. In TGA true statement a. A2 loud b
6.In TGA true statement a.A2 loud b.Arterial switch is the best option in the presence of pulmonary obstruction c.Cardiac catheterisation is the investigation of choice d.Egg on side in X ray always present

114. 7. RVH in TGA at birth is defined by a. Monomorphic R wave in V1 b
7.RVH in TGA at birth is defined by a.Monomorphic R wave in V1 b.T upright after 1week in V1 c.RS ratio <1 in V6 d.Incomplete RBBB

116. b.1.2L/Min/m2 c.1.5L/Min/m2 d.0.5L/Min/m2
8. Effective pulmonary blood flow(Qep)
a.0.9L/Min/m2
b.1.2L/Min/m2
c.1.5L/Min/m2
d.0.5L/Min/m2

117. 9. Anatomical right to left shunt a. 9L/Min/m2 b. 6L/Min/m2 c. 1
9.Anatomical right to left shunt a.0.9L/Min/m2 b.0.6L/Min/m2 c.1.5L/Min/m2 d.2L/Min/m2

118. 10. Physiological right to left shunt equals to a. 11. 1L/Min/m2 b
10.Physiological right to left shunt equals to a.11.1L/Min/m2 b.15L/Min/m2 c.20L/Min/m2 d.7L/Min/m2