1. Transposition of the great arteries (TGA) is a congenital heart defect where the aorta arises from the right ventricle and the pulmonary artery arises from the left ventricle. 2. TGA has an incidence of 5-7% of all congenital heart defects and is usually an isolated defect in 90% of cases. 3. After birth, mixing of saturated and unsaturated blood cannot occur properly due to the unsuitable ventricular-arterial connections, leading to hypoxemia.

1. TRANSPOSITON OF
GREAT ARTERIES
Dr. Harshil Joshi
UNMICRC

2. INTRODUCTION
 TGA - most common etiology for cyanotic congenital heart disease
in the newborn.
5-7% of all patients with congenital heart disease.
Overall annual incidence is 20-30 per 100,000 live births,
TGA is isolated in 90% of patients
Rarely associated with syndromes or extracardiac malformations.

3. • “There is probably more controversy surrounding the definition of
‘transposition’ than any other term in paediatric cardiology”
(Anderson-Pathology of Congenital heart disease 1981)

4. Definition
Malposition-
“when the great arteries exhibit abnormal spatial relation but
concordant ventricles of origin, they are said to be Malposed, not
Transposed.”

5. Definition
Farre coined the term “transposition” of the aorta and pulmonary artery
in 1814
“the aorta is arising out of the right ventricle and pulmonary artery is
coming from left ventricle.”

6. Definition
•TGA-Origin of Aorta above the morphologically
right ventricle and the pulmonary artery above the
morphologically left ventricle.
•DORV-Origin of both great arteries entirely or
predominantly above the RV
•DOLV- Origin of both great arteries entirely or
predominantly above the LV
•ACM-Origin of malposed Ao above the LV and
origin of malposed PA above the RV.

7. NORMAL EMBRYOLOGIC DEVELOPMENT
The superior end of primitive RV is initially
continuous with conus cordis and truncus that will
eventually give rise to both aortic and pulmonary
outflow.

8. Complicated
realignment causes the
right side of canal to
move and align with
future RA & RV. During
the same time the AV
canal is divided into
right and left canals by
growth of superior and
inferior endocardial
cushions which meet to
form the septum
intermedium.

9. Venrticular Septation
The two primitive ventricles begin to dilate with
continuous growth of myocardium outside and
traberculae formation on the inside with resultant
muscular IVS between them.
The growth of muscular IVS halts in middle of 7th
week
before its leading edge meets the septum intermedium. The
space between the free rim of muscular IVS and fused
endocardial cushions is called the IVF, later closed by
membranous IVS.
Septum intermedium
Muscular IVS

10. Truncal & Conal septation
During 5th
week opposing ridges appear in cephalic part of
truncus- right superior and left inferior truncal swellings
(neural crest origin)
They grow towards each other in a spiral manner
foreshadowing the future course of Aorto-pulmonary septum.
Simultaneously right dorsal and left ventral conal cushions
develop.

11. The proximal extent of right conus cushion
terminates at the superior border of right AV orifice.
With conal cushion fusion the septum divides the conus
into Anterolateral outflow tract of RV and posteromedial
outflow tract of LV.

12. The IVF found above muscular IVS is reduced in size
with completion of conus septum. Proliferation of
inferior AV cushions along top rim of muscular IVS and
fusion with abutting conus septum results in complete
closure of IVF and membranous IVS results

13. EMBRYOGENIC THEORIES
•Straight truncoconal septum hypothesis
incriminating the abnormal septation of aorta and
pulmonary trunk.
•Abnormal fibrous skeleton hypothesis where PA-
MV continuity occurs instead of AO-MV continuity.
•Abnormal embryonic hemodynamic hypothesis
caused by obstructive and altered flow
characteristics.
•Inverted truncal swelling theory citing inverted
development below the semilunar valves.

15. DEFINITION
• Complete transposition of the great arteries (TGA) is a congenital
cardiac anomaly in which the aorta arises entirely or largely from the
right ventricle (RV) and in which the pulmonary trunk arises entirely
or largely from the left ventricle (LV), known as ventriculoarterial
discordant connection.

18. Shunt

19.  HISTORICAL NOTE
The first morphologic description of TGA is attributed to Baillie in
1797.
The term transposition of the aorta and pulmonary artery was coined by
Farre.
Surgery of TGA commenced in 1950 when Blalock and Hanlon at Johns
Hopkins Hospital described a closed method of atrial septectomy.
In 1953, Lillehei and Varco described a "partial physiologic correction"
(or atrial switch) consisting of anastomosis of right pulmonary veins to
right atrium and inferiorvena cava (IVC) to left atrium, a technique that
became known as the "Baffes operation.

20. History cont….
• Palliation of TGA was revolutionized when Rashkind and Miller in
Philadelphia introduced balloon atrial septostomy (BAS) in 1966.
• Senning in 1959, who refashioned the walls of the right atrium and the
atrial septum to accomplish atrial-level transposition of venous return.
• The Mustard procedure, in which the atrial septum is excised and a
pericardial baffle used to redirect systemic and pulmonary venous flow
was successfully introduced at the Toronto Sick Children's Hospital in
1963 and reported in 1964.

21. • In 1969,Rastelli and colleagues combined intraventricular tunnel repair
(LV to aorta) of the double outlet RV operation with a rerouting valved
extracardiac conduit (RV to pulmonary artery) and closure of the origin
of the pulmonary trunk from the LV to produce an anatomic repair of
TGA, VSD, and LVOTO.
• Idriss and colleagues attempted such a procedure in two patients with an
intact ventricular septum in 1961 using cardiopulmonary bypass (CPB),
transferring the great arteries and a ring of aorta carrying the coronary
arteries.
• Jatene and colleagues in Brazil achieved a major breakthrough in 1975
with the first successful use of an arterial switch procedure {Jatene
procedure), applying it in infants with TGA and VSD.
History cont….

22. MORPHOLOGY
1. Right Ventricle
• The RV is normally positioned, hypertrophied, and large in TGA.
• In about 90% of cases,the aorta is rightward and anterior and ascends
parallel to the posterior and leftward pulmonary trunk.
• There is less wedging of the pulmonary trunk between mitral and
tricuspid valves in TGA than of the aorta in normal hearts. As a result, a
larger area of contiguity exists between mitral and tricuspid valves than
normally.
• These atrioventricular (AV) valves may be at virtually the same level.

23. 2.Left Ventricle
• Typically pulmonary-mitral fibrous continuity exists, comparable to
aortic-mitral continuity in the normal heart.
• In the normal heart the LV wall is same thickness as the RV wall in
utero. After birth, LV wall thickness increases progressively, whereas the
RV wall becomes relatively thinner.
• In TGA the RV wall is considerably increases in thickness with age.
When the ventricular septum is intact and no important pulmonary
stenosis is present, the LV wall is of normal thickness at birth. Wall
thickness remains static, however, leading to less than normal thickness
within a few weeks of birth and a relatively thin wall by age 2 to 4
months.

24. • When a VSD is present, LV wall thickness increases slightly less than in
the normal heart but remains well within the normal range during the first
year of life.With LVOTO (pulmonary stenosis) the evolution is similar.
• In infants with TGA the LV cavity is the usual ellipsoid in shape at birth
but soon becomes banana shaped. Alteration in LV function accompanies
this geometric change.
• RV function is usually normal in TGA in the perinatal period.
Thereafter, when the ventricular septum is intact, RV end-diastolic
volume is increased and RV ejection fraction decreased.
• Depressed RV ejection fraction is unlikely to be caused by increased
afterload or decreased preload and probably results from depressed RV
function from relative myocardial hypoxia or the geometry of the
chamber.

25. 3. Atria
• The atria are normally formed in TGA. Right atrial size is usually larger
than normal, particularly when the ventricular septum is intact.

26. 4. Conduction System
• The AV node and bundle of His lie in a normal position, although the AV
node is abnormally shaped and may be partly engulfed in the right
trigone.
• The left bundle branch originates more distally from the bundle of His
than usual.

27. RELATIONSHIP OF THE GREAT
VESSELS
•COMMONEST arrangement is aortic root is
anterior and to the right of the pulmonary trunk.
•However all possible permutations and relations
may be viewed.
•In almost all arrangements the aortic sinuses bearing
the coronaries face the pulmonary artery.

28. Arterial relationships
•Relationship of the great
arteries and their valves
• Aortic position around
pulmonary valve
(Bargeron,1981)

29. Coronary Anatomy
 Yacoub classification
(Thorax 33;418, 1978)
Type A: LCA from Lt. sinus &
RCA from the Rt. sinus.
Type B: Single coronary artery.
Type C: Two para-commissural
ostia with or without
intramural course.
Type D: RCA and circumflex
take origin from the right
ostium, LAD alone takes origin
from the left ostium.
 Type E: RCA and LAD take
origin from the left ostium,
circumflex alone takes origin
from the right ostium

30. Coronary Anatomy
•Other than origin , important to note origin in
relation to the sinuses- radial, tangential, vertical
origin.
•PROBLEMS
•Eccentric origin
•High origin
•Tangential takeoff across the aortic wall
•Crossing a commissure of the aortic valve
•Intramural coronaries

32. Coexisting Cardiac Anomalies
1. Ventricular Septal Defect
• The approximate distribution of VSD location includes perimembranous
(33%), AV canal (5%), muscular (27%), malalignment (30%).
• When septum is displaced to the right, the pulmonary trunk may be
biventricular in origin and over a juxtapulmonary VSD and may be
associated with subaortic stenosis or aortic arch obstruction (arch
hypoplasia, coarctation, or interruption).
• Posterior (leftward) malalignment is associated with varying degrees of
LVOTO–subpulmonary stenosis, annular hypoplasia, or even
pulmonary valvar atresia.
• The conal septum may be absent or almost gone, and the VSD is then
juxta-arterial (doubly committed).

33. 2. Left Ventricular Outflow Tract Obstruction
• Development of LVOTO, which produces subpulmonary obstruction, is
part of the natural history of many patients with TGA.
• The obstruction may be dynamic or anatomic.
• Dynamic type of LVOTO, developing in patients with TGA and intact
ventricular septum, is the result of leftward bulging of the muscular
ventricular septum secondary to higher RV than LV pressure.
• The septum impinges against the anterior mitral leaflet in combination
with abnormal systolic anterior leaflet motion (SAM). Thus, the
mechanism is similar to that present in hypertrophic obstructive
cardiomyopathy, but there is no asymmetric septal hypertrophy.
• In patients with TGA and VSD, stenosis is usually subvalvar and valvar.
Subvalvar stenosis is in the form of a localized fibrous ring, long tunnel-
type flbromuscular narrowing, or muscular obstruction related to
protrusion of the infundibular septum into the medial or anterior aspect of
the LV outflow tract.

34. 3. Patent Ductus Arteriosus
• Patent ductus arteriosus (PDA) is more common in hearts with TGA than
in hearts with ventriculoarterial concordant connection.
• Persistence of a large PDA for more than a few months is associated with
an increased prevalence of peripheral vascular disease.

35. 4. Tricuspid Valve Anomalies
• The tricuspid to mitral anulus circumference ratio, normally greater than
1, is less than 1 in 50% of patients. This reduced ratio is most marked in
hearts with associated coarctation.
• Functionally important tricuspid valve anomalies are present in only
about 4% of surgical patients.
• The tricuspid leaflets can be redundant and dysplastic in TGA.
• Accessory tricuspid tissue may prolapse through the VSD and produce
LVOTO.
• The tricuspid anulus may be dilated, the valve may be hypoplastic in
association with underdevelopment of the RV sinus.
• Anular overriding or tensor straddling or both can occur.

36. 5. Mitral Valve Anomalies
• Important structural anomalies of the mitral valve are present in 20% to
30% of hearts with TGA, mostly in combination with a VSD.
• Mitral valve anomalies can be categorized into four groups, as those
affecting the
• Leaflets
• Commissures
• Chordae tendineae
• Papillary muscles
• The most important from a surgical standpoint are those of mitral valve
overriding or straddling, in which the mitral valve leaflet is frequently
also cleft.

37. 6. Aortic Obstruction
• Coexisting aortic obstruction can be discrete (coarctation, or less often
interrupted aortic arch) or caused by distal arch hypoplasia.
• it occurs in 7% to 10% of patients with TGA and VSD.
• This coexistence is more frequent when the VSD is juxtapulmonary and
the pulmonary trunk is partly over the RV in association with rightward
and anterior displacement of the infundibular septum and with some
subaortic narrowing.
• When there is associated coarctation, underdevelopment of the RV sinus
is more common.

38. 7. Right Aortic Arch
• Right aortic arch occurs in about 5% of patients with TGA.
• It is more common when there is an associated VSD than when the
ventricular septum is intact and when there is associated leftward
juxtaposition of the atrial appendages.

39. 8. Leftward Juxtaposition of Atrial
Appendages
• Leftward juxtaposition of the atrial appendages occurs in about 2.5% of
patients with TGA.
• Bilateral conus and dextrocardia seem more common in TGA associated
with leftward juxtaposition than in TGA generally.

40. 9. Right Ventricular Hypoplasia
• RV hypoplasia was found to some degree in 17% of the necropsy series
of TGA reported by Riemenschneider and colleagues.

41. 10. Abnormal pulmonary flow
• The maldistribution is dependent on a common anatomic
feature found in transposition, abnormal rightward
inclination of the main pulmonary artery, which results in a
straight ejection direction from left ventricle to main
pulmonary artery to right pulmonary artery.
• The abnormally increased distribution of pulmonary blood
flow to the right lung in TGA often is associated with some
degree of hypoplasia of the left pulmonary arterial vessels
and is further manifested in the occasional reports of
unilateral, always left-sided, pulmonary vein stenosis or
hypoplasia

42. PATHOPHYSIOLOGY

43. PATHOPHYSIOLOGY
Fetal circulation
compatible with normal fetal survival and gestational
development.
• SVC Blood ---» TV ---» RV--- » ASC.AORTA
• Blood reaching coronary and cerebral circulations have slightly lower
blood glucose and Po2 than normal.
• Blood reaching pulmonary circuit and descending aorta has better
glucose conc. And higher Po2.
But birth weight remains unaffected.

44. PATHOPHYSIOLOGY
Birth
↓
PVR falls, SVR increases
↓
Two parallel circulation established.
↓
Desaturated blood gets more desturated, and oxegenated
gets more oxygenated
↓
Problem begins…

45. PATHOPHYSIOLOGY
Mixing
must be equal and bidirectional
Pumping
Unsuitable pump for Systemic
and Pulmonary bed

46. PATHOPHYSIOLOGY
Mixing
Concept of effective Pulmonary Blood Flow
Concept of effective systemic blood flow
The effective pulmonary blood flow, effective systemic blood flow,
and net anatomic right-to-left and net anatomic left-to-right shunts are
each equal to each other, and this volume is the intercirculatory
mixing: the flow in TGA on which survival depends

48. PATHOPHYSIOLOGY
Level of Mixing
Intracardiac
patent foramen ovale
ASD
VSD
Extracardiac
PDA
bronchopulmonary collateral
circulation

49. PATHOPHYSIOLOGY
Mixing
Direction of mixing
Interatrial shunting
Ventricular systole – Lt. to Rt.
Ventricular Diastole- Rt. To Lt.
Interventricular shunting
Isovolumetric contraction- Lt. to Rt.
Ventricular ejection- Rt. To Lt.
Isovolumetric Relaxation- Rt. To Lt.
Early diastole - Rt. To Lt.
[Sommer RJ et al JACC 16; 1437,1990]

50. PATHOPHYSIOLOGY
Pump
Geometry
End diastolic volume
Systolic output
Ejection Fraction
Wall thickness

51. PATHOPHYSIOLOGY
Pump
following three conditions:
Pure LV volume overload- TGA,IVS
Pure LV pressure overload- TGA,IVS,PS
LV Pressure +Volume overload- TGA,VSD with or without PS.

52. PATHOPHYSIOLOGY
Pump
Geometry
LV-
Spherical at birth
Banana shaped later.
RV-
Crescent shape
Spherical later.

53. PATHOPHYSIOLOGY

54. PATHOPHYSIOLOGY
Pump
End diastolic volume (Circulation 44;899, 1971)
At birth it is normal for both LV and RV
With IVS –
RVEDV=normal in first month then increase
LVEDV=normal initial 3-4months then ↑es=180%
With VSD-
RVEDV=increases from the first month 163+/-25%
LVEDV=increases about 259% of normal
With VSD,PS
RVEDV=normal in first month then 124+/-26%%
LVEDV=117% of normal
RA volume ↑ to 181% but LA volume remains normal.

55. PATHOPHYSIOLOGY
Pump
Wall thickness( correlation with age)
Normal Heart-
RV- normal
LV- Good
TGA
RV-potential (growth rate same in+/- VSD)
LV- with increasing age growth rate is slow, being minimal for
the hearts with IVS.

56. PULMONARY VASCULAR DISEASE
The persistence of a large PDA in infants with intact ventricular septum
has been implicated as a cause for increased pulmonary vascular disease as
has prolonged hypoxemia or polycythemia
increases in pulmonary vascular muscularity and intimal hyperplasia with
vessel obstruction
Intense systemic hypoxemia is commonly present, and local pulmonary
hypoxemia can result from increased bronchial arterial vessels and
bronchopulmonary anastomoses carrying hypoxemic systemic blood to the
precapillary pulmonary arterioles.
Thus, increased pulmonary vascular flow, pressure, and
vasoconstrictive factors, possibly in association with abnormal platelet and
red cell factors, can result in increased pulmonary vessel shear stress,
endothelial damage, microthrombi, and the early induction and rapid
progression of vascular disease.

57. Pathophysiology

58. Arterial Blood Gases and Metabolic
Responses
• pulmonary venous blood reflects chemoreceptor-stimulated
hyperventilation
• systemic arterial pO2 levels are rarely higher than 35 mm Hg, and the
pCO2 is usually normal
• Pulmonary pO2 levels may be increased to as high as 110 mm Hg and
the pCO2 levels reduced to 15 to 25 mm Hg

59. Natural History and Presentation
PHYSIOLOGICAL- CLINICAL CLASSIFICATION
 TGA (IVS or small VSD) with increased PBF
and small ICS
 TGA (VSD large) with increased PBF and large
ICS
 TGA (VSD and LVOTO),with restricted PBF
 TGA (VSD and PVOD), with restrictive PBF

60. TGA (IVS or Small VSD) Poor Mixing
 Includes infants without a VSD or with a VSD 3 mm or less in
diameter
 A patent foramen ovale or naturally occurring atrial septal defect
(ASD) is usually present.
 Cyanosis is apparent in half these infants within the first hour of life
and in 90% within the first day and is rapidly progressive.
 The systemic arterial pO2 may be as low as 15 to 25 mm Hg at
presentation, with resultant anaerobic glycolysis and severe
metabolic acidemia. The newborn infant may not manifest acidemia
in the first day or two of life, perhaps because of favorable blood
tissue dissociation characteristics or tissue resistance factors.
 Inevitably, unless intracardiac mixing is improved by palliative or
corrective intervention, severe hypoxemia results in advanced
acidemia, hypoglycemia, hypothermia, and eventual death

61. TGA (VSD large) Good Mixing
Presentation in this TGA group generally occurs in the latter half of the first month,
with mild cyanosis and signs of heart failure resulting from pulmonary venous
hypertension and myocardial failure.
Tachycardia, tachypnea, important liver enlargement, and moist lung bases are
present. The heart is more active and usually larger than in the poor-mixing group.
A large VSD is associated with a moderate-intensity pansystolic murmur along the
lower left sternal edge that may not be present initially.
There is usually an apical middiastolic murmur or gallop rhythm and narrow splitting
of the second heart sound with accentuation of the pulmonary component.
With a large PDA, a continuous murmur, bounding pulses, and an apical
middiastolic murmur are present in less than half the patients, even when the
ventricular septum is intact.

62. TGA ( VSD and LVOTO)
Large VSD with LVOTO is the least common of the three TGA groups.
LVOTO is associated with a decreased Qp and poor mixing, but
pulmonary venous hypertension and associated symptoms and signs do
not develop because of lack of increase in Qp.
Heart failure is therefore not present.
 cyanosis is severe from birth.
Chest radiography shows a near normal-sized heart with normal or
ischemic lung fields.
 ECG shows biventricular hypertrophy.

63. TGA (VSD and PVOD)
Maybe mildly tachypnea, cyanotic at birth
secondary increase in cyanosis with increasing haematocrit
Symptoms of CHF improves

64. TGA with or without VSD + PDA
Mild cynosis in initial few weeks of life.
By end of first week symptoms of CHF starts.
Sudden deterioration of clinical status with severe cynosis
indicates spontaneous PDA closure

65. Reverse differential cyanosis, that is, cyanosis of the upper body greater
than that of the lower body, is rare and indicates the presence of TGA with
a PDA and pulmonary artery-to-aorta shunting
prompt echocardiographic examination is clearly indicated for any
cyanotic neonate with suspected congenital heart malformation
Risk for necrotizing enterocolitis may be increased in neonates with TGA
and a large PDA.
Mesenteric circulation may be at risk because of
(a) retrograde diastolic flow in the descending aorta producing a steal
phenomenon,
(b) Decreased oxygen delivery,
(c) Cardiac catheterization/angiography and umbilical artery
catheterization in some cases.

66. ARTERIAL PULSE and JUGULAR
VENOUS PULSE
• the bounding pulses,the scalp varices, and the warm
extremities to the large volume of highly unsaturated blood
recirculating in the hyperkinetic low-resistance systemic
vascular bed
• Diminished femoral pulses call attention to coexisting
coarctation of the aorta with anterior and rightward deviation
of the infundibular septum(subaortic stenosis).
• jugular venous pulse is elevated

67. PALPATION
• A loud palpable second heart sound at the left base originates in the
aortic valve because the transposed aorta is anterior
• A left ventricular impulse is not identified in neonates because
ejection is at a low systolic pressure.

68. AUSCULTATION
• Pulmonary ejection sounds
• Midsystolic flow murmurs originate in the transposed
anterior aorta
• holosystolic murmur of ventricular septal defect
• The murmur of a nonrestrictive patent ductus arteriosus
is confined to systole
• Mid-diastolic murmurs are generated across the mitral
valve when pulmonary blood flow is increased
• A loud and single second heart sound is the aortic
because the aorta is anterior

69. ELECTROCARDIOGRAM
•Tall peaked right atrial P waves soon emerge
because mean right atrial pressure is increased
•Right axis deviation is most striking when an atrial
septal defect occurs with pure right ventricular
hypertrophy
•Biventricular hypertrophy is evidence of a
nonrestrictive ventricular septal defect with low
pulmonary vascular resistance

70. X Ray
• In the neonate with TGA/IVS, the diagnostic triad includes
(a) oval or egg-shaped cardiac silhouette with narrow superior
mediastinum
(b) mild cardiomegaly
(c) increased pulmonary vascular markings.

71. • right border of the egg consists of the right atrium
• the convex left border is the left ventricle.
• In the lateral projection, the heart assumes a circular appearance
because an enlarged right ventricle merges with the anterior aorta, and
an enlarged left ventricle merges with the dilated posterior left atrium

72. Echocadography
• Fetal Echocardiography
• Postnatal Echocardiography

73. Cath Study
• Those hemodynamically unstable and rquire BAS.
• Where more physiologic and anatomic data is required concerning
coronary artery, the VSD, degree of LVOTO.
• Presence of other complex cardiac anomalies like CoA, interrupted
aortic arch.
• To quantify pulmonary vascular resistance in patients of TGA with
VSD

74. Medical management
• Important in patients with TGA with IVS.
• Focuses on hemodynamic stabilization and correction of
physiological abbarations caused by cyanosis and poor perfusion.
• Correction of acid base balance, maintainance of normothermia,
prevention of hypoglycemia.
• PGE1 infusion to maintain patencty of ductus to provide mixing of
saturated and desaturated blood.
• BAS

75. Aims of surgery
• To make the parallel circulations into series. So that oxygenated
blood goes to aorta and deoxygenated blood goes to pulmonary trunk.
• Correction of other cardiac anomalies like VSD, PDA, TR, AORTIC
OBSTRUCTION, LVOTO.
• To provide a near normal functional status to patients.

76. Treatment- Palliative
• balloon atrial septostomy
• surgical septectomy
• partial venous correction
• pulmonary artery banding
• systemic-to-pulmonary shunts

77. Surgery for TGA/IVS or TGA/VSD without
Associated Outflow Tract Obstruction
• Physiologic Correction (Atrial Switch)
• Senning repair-- the atrial baffle is fashioned in situ using tissue from
the right atrial wall and interatrial septum
• Mustard operation--- after resection of most of the atrial septum, the
baffle is made from autologous pericardial tissue or (rarely) synthetic
material

78. Complications of atrial switch
• caval and pulmonary venous obstructions
• residual intra-atrial shunts
• Atrial and ventricular arrythmias
• Tricupid valve regurgitation
• Right ventricular failure

79. Explanations for postatrial repair subnormal
right (systemic) ventricular function
• Right ventricular myocardial fiber arrangements is not optimum and
mismatch between right ventricular coronary blood supply and
systemic ventricular work demand.
• The left ventricular free wall is composed predominantly of stratum
compactum, whereas the right ventricular free wall consists
predominantly of stratum spongiosum.
• Transposed ventricular pressure relationships force the ventricular
septum to bulge posterior-leftward and to present a concave septal
surface during contraction.
• the tricuspid valve is supported by relatively small papillary muscles
in comparison with the mitral valve, and this, in conjunction with the
abnormal concave right ventricular septal surface, may result in TR.

80. Anatomic Correction (Arterial Switch)
• The great arteries are transected in a manner that allows eventual
reanastomosis of the distal aortic segment to the proximal pulmonary
artery (neoaortic root). Transfer of the coronary arteries to this
pulmonary segment is facilitated by their excision from the aortic
sinus with a cuff of adjacent aortic wall. The proximal aortic segment
(neopulmonary root) may be connected to the distal pulmonary artery
segment by an end-to-end anastomosis using the innovative maneuver
of Lecompte

81. • Anatomic variants that may impact operative mortality include
• (a) an intramural course of a coronary artery
• (b) a retropulmonary course of the left coronary artery
• (c) multiple VSDs
• (d) coexisting abnormalities of the aortic arch
• (e) straddling AV valves

82. Surgery for Transposition of the Great
Arteries with Low Left Ventricular Pressure
• Pulmonary artery banding has been used to increase left ventricular
afterload and stimulate hypertrophy
• Intraoperative TEE is useful in guiding placement of the PAB. The
band is tightened enough to flatten the intraventricular septum by
shifting it toward the RV
• When this technique is used, left ventricular function may be
extremely impaired following banding; therefore, systemic-to-
pulmonary artery shunt is frequently placed to ensure adequate
pulmonary blood flow
• The interval period between banding and correction is frequently
characterized by a low output syndrome, most likely resulting from a
combination of acute (fixed) right ventricular volume overload from
the shunt and acute (transient) left ventricular dysfunction from the
pulmonary artery band

83. Left Ventricular Preparation
• direct pressure measurements in the left ventricle or the ratio of left-
to-right ventricular pressure may not be predictive of the capability of
the left ventricle to perform systemic work
• in a neonate with immediate closure of the ductus and a prompt fall in
pulmonary vascular resistance, the left ventricular systolic pressure
can fall to less than half the systemic levels (or 25 to 30 mm Hg) as
soon as 4 or 5 days after birth
• A 6-week-old patient whose ductus has only recently closed will more
likely have a prepared left ventricle than a 6-week-old patient whose
ductus closed directly after birth

84. Empiric criteria to determine adequate left
ventricular preparation
• an absolute left ventricular systolic pressure that is appropriate for age
• a left ventricular pressure at cardiac catheterization that is 70%
systemic levels (left to right ventricular ratio >0.7)
• left ventricular muscle mass that is within the normal range for body
surface area

85. other innovative approaches
• percutaneously adjustable band
• partial balloon occlusion of the main pulmonary artery with a
percutaneously placed balloon-tipped catheter
• systemic-to-pulmonary artery shunting alone
• primary arterial switch with left ventricular assist in the perioperative
period

86. Anatomic Correction without Coronary
Translocation
• Damus, Kaye, and Stansel(DKS)

87. Surgery for Transposition of the Great
Arteries with Associated Left Ventricular
Outflow Tract Obstruction
• dynamic LVOTO is reduced or eliminated in older infants with
TGA/IVS following pulmonary artery banding
• Transpulmonary or transmitral resection has been performed for
severe fixed obstruction caused by a short, discrete fibromuscular
subvalvar shelf
• the Rastelli operation
• REV(Reparation a L'etage Ventriculaire) by Lecompte

88. Surgery for Right Ventricular Failure
Following Physiologic Correction
• tricuspid valvuloplasty/replacement
• cardiac transplantation
• anatomic correction
• Damus,Kaye,Stansel operation may be technically easier to perform,
but it requires the use of a prosthetic conduit from the right ventricle
to pulmonary arteries

89. Surgery for TGA/VSD and Pulmonary
Vascular Obstructive Disease
• Advanced pulmonary vascular disease characterized by calculated
pulmonary vascular resistances >10 U or grade 4 (H-E) histologic
changes is considered a contraindication to closure of the VSD
• Palliative switch (either atrial or arterial) allows more effective
pulmonary and systemic flows and a significantly improved systemic
arterial oxygen saturation.

92. Initial palliative management
• Most patient at admission are dehydrated, acidosis and cyanotic
• Give hydration therapy with oxygen
• Prostagalandin E1 therapy
• Rashkind ballon septoplasty
• Ventilation may require
• Aggressive ventilation with high PEEP compromise PBF
• High Fio2 may close PDA
• Maintain SaO2 of 80-85%

93. Anesthetic Goals in Patients with
Transposition of the Great Vessels
• Maintain heart rate, contractility, and preload to maintain cardiac
output. Decreases in cardiac output decrease systemic venous
saturation with resultant fall in arterial saturation.
• Maintain ductal patency with prostaglandin E1 (0.05-0.1 µg/kg/min)
in ductal-dependent patients.
• Avoid increases in PVR relative to SVR. Increases in PVR decrease
pulmonary blood flow and reduce intercirculatory mixing. In patients
with pulmonary vascular occlusive disease, ventilatory interventions
should be used to reduce PVR
• Reductions in SVR relative to PVR should be avoided. Decreased
SVR increases recirculation of systemic venous blood and decreases
arterial saturation.

94. Premeditation
• rarely necessary
• prostaglandin E1 infusion should be continued until cardiopulmonary
bypass (CPB)
• oral midazolam 0.5 to 1.0 mg/kg is a useful premedicant
• preoperative intravenous hydration

95. Monitoring
• blood pressure cuff, ECG, pulse oximeter, end-tidal carbon dioxide
monitor, and precordial stethoscope
• intraarterial catheter
• central venous catheters
• Nasopharyngeal, tympanic, and rectal temperature
• transesophageal echocardiography

96. Induction
• opioids alone in high doses (25-100 µg/kg fentanyl or 2.5-10 µg/kg
sufentanil)
• provide hemodynamic stability, do not depress the myocardium, and
blunt reactive pulmonary hypertension
• low-to-moderate doses (5-25 µg/kg fentanyl or 0.5-2.5 µg/kg
sufentanil) in combination with an inhalation agent
• avoid bradycardia
• Ketamine does not increase PVR as long as normocarbia is
maintained and hypoxemia avoided
• PCO2 ranging from 25 to 35 mmHg (3-5 kPa) (38), and pH ranging
from 7.50 to 7.56 (39) effectively reduce PVR in infants
• Hypercarbia, acidosis, and hypoxemia should be avoided
• Low PEEP and Low FiO2

97. Intraoperative Management
• Priming with Blood and Albumin
• Mainatian ACT
• Mainatain haematocrit more than 25%
• DHCA management
• Blood Cardioplegia
• CUF and MUF should be used
• Phenoxybenzamine can be used
• Milrinone should be loaded

98. Complication at off CPB
• SVC and IVC obstruction
• Pulmonary vein obstruction
• TEE is extremely useful for detecting venous obstruction
• Arrhythmias immediately following the atrial switch procedures may
be problematic
• Coronary hypoperfusion and Myocardial ischemia
• Mainatin high perfusion pressure on CPB
• Inotropic support of the LV and afterload reduction may be necessary
to terminate CPB

99. Post CPB
• overzealous volume infusion can result in LV distention and LA
hypertension
• LA hypertension produces elevations in PA pressure and distention of
the PA
• distention of the PA may compress or place tension on the coronary
ostia
• Weaned of bypass at 36 temp
• PD catheter and chest open decision depending on situation

100. Post op Care
• Depends on type of operation
• Ventilate for 24 hour…. Early extubation can be done in experience
center
• Mainatain normo or hypocarbia with min FiO2
• Narcotic analgesia
• Post op Echo
• ST segment monitoring
• U/O and Infection
• Inhaled NO to decrease PA pressure
• Milrinone or levosimendan- decrease afterload and inotropic
• Avoid high dose adrenalin– alpha effect

101. • If LA line present fluid accordingly
• left atrial (or pulmonary artery diastolic) pressure should remain low,
less than about 12 mmHg
• Accept mean BP of 35 mm hg in neonate
• In ASO maintain coronary perfusion
• Add noradrenalin to conteract milrinone induced very low afterload
• Lactate level and mix venous saturtation measure
• Strat RT feed or NG drip as early as possible
• Negative balance at the end of day
• Never give bolus fluid.. Low CVP is not indication for Fluid
• Echo guided fluid replacement

102. • In Atrial Switch
• Positive end-expiratory pressure (PEEP) is not used because it tends
to obstruct the SVC
• Infants are nursed in a slightly head-up position
• Atrial pressures are kept as low as is compatible with an adequate
cardiac output

103. Complication
• Low CO
• Coronary Ischemia
• Pulmonary hypertensive crisis
• Mesenteric Ischemia
• Convulsion
• Renal Failure
• Sepsis

104. THANK YOU