Presentation for students

1. CYANOTIC
CONGENITAL HEART DISEASE
Hristo A. Rahman
Department of Cardiovascular Surgery
St. George University General Hospital

2. Tetralogy of Fallot

3. Most common cyanotic CHD in children
surviving 1 year
Accounts for 4-6% of all CHDs
The four intracardiac lesions:
1. VSD;
2. Overriding aorta;
3. Narrowed RVOT;
(infundibular/subpulmonary)
4. RV hypertrophy
Tetralogy of Fallot
ToF

4. ToF is caused by underdevelopment of the
infundibular/conal septum leading to infundibular
obstruction of the RVOT causing compensatory RV
hypertrophy
Underdevelopment of infundibular septum
contributes to the VSD
Because of the misalignment of the VS, the aorta
overrides it
Pathophysiology

8. Haemodynamic consequences of ToF: the large VSD
results in equalisation of pressures between
ventricles
( no VSD murmur on auscultation)
There is a significant pressure gradient between the
RV and the PA due to pulmonary stenosis
( systolic murmur of pulmonary stenosis can be
detected at the left sternal edge)
As a result: more blood, only partially saturated, is
ejected into the aorta, and the lungs are only
partially perfused so that total oxygenation is poor
and cyanosis results

9. Degree of cyanosis depends on the degree of
pulmonary stenosis
If there is significant PS to virtual pulmonary atresia,
presentation is in the neonatal period because of
duct (PDA) dependency
A situation where the ductus arteriosus remains
patent as pulmonary blood flow is dependent on
receiving blood from the aorta via the duct
Initially there may be no signs, but as PS progresses,
cyanosis typically develops within the first year of life
Clinical features

10. BLUE BABY SYNDROME

11. Classically, hypercyanotic spells are thought
to be due to infundibular or subpulmonary
muscle spasm
Squatting is an adaptation by the child to such
hypoxic spells
This increases systemic vascular resistance
and venous return to the heart and
consequently blood is diverted into pulmonary
circulation with increased oxygenation
Lethargy and tiredness are also common

12. TOF symptomatic infant

13. ECG shows evidence of RA and RV hypertrophy
Chest radiograph demonstrates “boot-shaped”
heart with poorly developed lung vasculatur
The diagnosis is confirmed with Echo and
further assessed with cardiac catheterisation
prior to surgery
Investigations

14. Based on clinical progression and include:
1. severe cyanosis (as indicated by oxygen
saturation <80% on room air);
2. Hypercyanotic spells;
3. Dyspnoea on effort;
4. Syncopal attacks;
5. Polycythaemia.
The choice of operation depends on
anatomical considerations, age and general
condition of the patient
Indications for surgery

15. Several approaches to operative treatment of ToF:
Symptomatic infant:
1. Complete primary repair as a first procedure;
2. Palliative procedure;
- Surgery
- Stenting
Asymptomatic infant: elect for total primary repair
early (first 6 months, but usually within the first 3
years of life)
Surgical options and treatment

16. Elective total primary repair (in asymptomatic)
advantages:
1. Reduces the number of operations;
2. Restores normal oxygen saturation earlier in
life and so helps development;
3. Repairing the defect early, leads to less RV
hypertrophy, which may reduce the
frequency of late arrhythmias

17. Total correction:
Via median sternotomy; can include dealing
with a previously constructed systemic-PA
shunt;
The correction is performed on CPB;
VSD is closed with synthetic patch;
Stenotic infundibulum or pulmonary valve is
dealt with and the RVOT is widened using
synthetic patch

20. Palliation
required in neonates
Palliative procedures (via either sternotomy or
thoracotomy) divert systemic blood into the
pulmonary circulation and may be used to improve
oxygenation;
CPB is avoided/only in unstable pts.;
Many types of systemic-to-PA shunts have been
used;
Original and most popular of all is: RSA-to-RPA
Blalock-Taussig shunt (1945), or a modification
(1970s) in which an interposition PTFE conduit is
used-Modified BT shunt (MBTS)

21. Alfred Blalock Hellen Taussig

24. “Thomas”-Blalock-Taussig shunt

25. Blalock-Taussig shunt

26. Waterston-Cooley (Asc.Ao-RPA shunt)
Potts (Desc.Ao-LPA shunt)
Laks-Castaneda modification of left BTshunt
Other S2P shunts
(rarely used nowadays)

27. Palliative invasive percutaneous procedure;
High-risk symptomatic premature neonates with low
birth weight and suitable anatomy;
Balloon pre-dilation prior to stenting RVOT;
Promising results (significant increase in O2 sat)
Option for the critically ill neonates;
Pts. undergo elective total surgical correction with stent
removal on CPB;
Stenting of RVOT

29. Late survival at 5-10 years following
correction of ToF is 95%;
Operative mortality for repair group 1-10%;
Incidence of Redo-procedures following ToF
repair 5-10%
Surgical results

31. Transposition of great arteries
TGA

32. Described by Morgagni;
Second most common cyanotic CHD;
2.5-5% of all CHDs;
Most common cause of cyanosis from
congenital heart defect discovered in the
newborn period
Transposition of great arteries
TGA

33. TGA results from abnormal development and
typically occurs when Ao. arises from the RV
and the PA from the LV
The resulting transposition causes the
pulmonary and systemic circulations to run in
parallel rather than in series, so that
oxygenated pulmonary venous blood returns
back to the lungs and desaturated systemic
venous blood is pumped around the body
Pathophysiology

34. TGA is incompatible with life and mixing of
the blood must occur through associated
shunts
This can be at:
1. Atrial level: through PFO or ASD;
2. Ventricular level: through VSD;
3. Great arteries level: through PDA (PIVA)

35. Severe central cyanosis in the first 48 hours of life,
with the cyanosis progressing in the first week as
the PDA (PIVA) closes
If there is a large ASD or VSD there may be minimal
cyanosis initially
Typically, progress is poor and, as pulmonary
vascular resistance declines in the neonatal period,
high pulmonary flow develops, with cardiac
enlargement and LV failure
CHF is the most common cause of death
Clinical features

36. Chest radiograph demonstrates pulmonary
plethora, with the heart having an ”egg on its
side” appearance, with small pedicle ( aorta
infront of the PA)
Cardiac catheterisation and echocardiography
confirm the diagnosis and delianate the
anatomy
Additional defects such as ASD, VSD, PIVA or
abnormalities of the AV valves should be sought
Investigations

37. The outcome for infants with TGA in the first year of
life without some form of intervention to increase
systemic and pulmonary venous admixture is death
in 80-90% of cases
Initial palliation is by percutaneous Rashkind
balloon atrial septostomy, or alternatively
intravenous prostaglandin to keep the ductus open
Definitive repair is usually the Arterial switch
procedure, which has replaced the Atrial switch of
buffle (Mustard or Senning) operation, because of
reduced long-term complications
Indications for surgery

38. The successful short-term palliation of balloon
atrial septostomy allowed delaying definite repair
at up to 6 months of age
It involves passing a balloon-tipped catheter across
the atrial septum through a patent foramen ovale,
then inflating the balloon and forcibly retracting it
back into the RA, creating a tear in the atrial
septum and adequate mixing of the two
circulations
Surgical options and Treatment
Palliative procedure
Rashkind balloon atrial septostomy

39. Rashkind balloon atrial septostomy

40. Rashkind balloon atrial septostomy

41. Via right posterolateral thoracotomy
Excision of atrial septum allows mixing of
blood between RA and LA
No CPB
Surgical options and Treatment
Palliative operation
Blalock-Hanlon atrial septectomy

42. Blalock-Hanlon atrial septectomy

43. DEFINITIVE REPAIR
Surgical options and Treatment

44. In the 1960s,Mustard and Senning
independently developed the atrial switch or
baffle procedures to redirect atrial blood into
the appropriate ventricle so that oxygenated
blood reaches the systemic circulation and
deoxygenated blood goes into pulmonary
circulation
Following palliation, they were usually carried
out in infants between 6 months and 1 year of
age and were physiological as opposed to
anatomic repairs
Atrial switch operation
Mustard / Senning operation

45. However, they were associated with number of
problems developing post CPB;
Atrial/SV arrythmias were common;
Obstruction of the surgically created atrial
baffles could occur, and because the RV bears
the load of the systemic circulation, both RV
muscle and tricuspid valve may not cope,
leading to RV failure
Atrial switch operation
Mustard / Senning operation

46. Atrial switch operation
Mustard / Senning operation

47. Atrial switch operation
Mustard / Senning operation

48. Total anatomical correction or arterial switch
is currently the standard procedure and is
carried out in the neonatal period
This involves:
1. Disconnecting the PA from the LVOT and the
aorta from the RVOT;
2. Moving the aorta to the LV and the PA to the
RV;
3. Moving the coronary artery ostia to the aorta
Arterial switch operation

49. Arterial switch operation

50. Arterial switch operation

51. If the arterial switch operation is performed in the
first few weeks, the LV is still capable of
generating systemic pressures but, if not corrected
in time, the LV will fail as pulmonary vascular
resistance falls and later arterial switch is unlikely
to be successful
This can be overcome by a two-stage procedure
whereby the PA is first banded to “tone up” the LV
The arterial switch procedure is increasingly being
carried out in the newborn with TGA and intact
ventricular septum without prior PA Banding
procedure
Arterial switch operation

52. Results
Significant mortality in the neonatal period
Operative mortality approaching that of a
Fallot’s repair
Impressive long-term results
Arterial switch operation

53. Total anomalous pulmonary venous
connection TAPVC

54. TAPVC: 1-2% of CHD
In TAPVC pulmonary venous drainage is
disconnected from the LA and drains into the
systemic venous circulation at some other point:
1. Inferior vena cava (IVC)
2. Superior vena cava (SVC)
3. Coronary sinus (CS)
4. Right atrium (RA)
Total anomalous pulmonary venous
connection TAPVC

55. TAPVC is caused by atresia of the common
pulmonary vein, leading to drainage of
pulmonary veins into either embryological
cardinal, umbilical, vitelline or systemic venous
systems
For the newborn to survive, there is mixing of
the systemic and pulmonary circulations
through a patent foramen ovale or associated
ASD
Pathophysiology

56. Supracardiac (type 1)
PVs drain to a confuence behind the RA,
through embryonic residual called
vertical/ascending vein to the innominate
vein (50% of cases)
Types of TAPVC

57. (Intra)/Cardiac (type 2)
PVs drain either into the CS or directly into
the RA via venous confluence (30% of cases)
Types of TAPVC

58. Infracardiac (type 3)
PV drain via venous confluence and
descending vein to the portal vein or IVC
below the diaphragm (15% of cases)
Types of TAPVC

59. Mixed (type 4)
Combinations of the three types (5% of cases)
Types of TAPVC

60. TAPVC presents after the first week of life with
cyanosis that is mild to moderate depending
on pulmonary flow
Infants with high pulmonary flow develop:
1. Cardiac failure;
2. Recurrent chest infections;
3. Failure to thrive;
4. Feeding difficulties
Clinical features

61. If high pulmonary flow is associated with large
ASD, cyanosis is often minimal and the lesion
is tolerated well
If there is additional venous obstruction ( as
can occur in type 3 Infracardiac TAPVC),
cyanosis presents at birth with:
1. Dyspnoea (SOB);
2. Pulmonary oedema
Clinical features

62. ECG: right axix deviation and signs of RV
hypertrophy
Chest radiograph: depends on the anatomy but
may be normal or show the ground glass (or
“snowstorm”) appearance of pulmonary venous
congestion
Echocardiography and cardiac (pulmonary)
angiography are necessary to confirm the
diagnosis and establish the location of the
anomalous drainage
Investigations

63. Prognosis without operation is poor
80% of symptomatic infants die before 1 year of
age
There is no long-term palliative intervention fot
TAPVC
Total correction of TAPVC is necessary for all
cases
Indications for surgery

64. The surgical principle is to re-establish the
pulmonary venous drainage into the LA
The exact operative technique depends on the
anatomy and type of TAPVC
Operative mortality is higher in younger patients
and in those with complex lesions
Long-term results for survivors of the operation are
generally good
Late death following repair is uncommon
Surgical options and Treatment

65. Supracardiac TAPVC
Total correction procedure

66. Eisenmenger syndrome

67. Eisenmenger syndrome:
1. Less common as corrective surgery is undertaken
increasingly early;
2. Fewer patients develop fixed increase in their
pulmonary vascular resistance (PVR)
Occurs following the reversal of left-to-right shunt
across a previous left-to right shunt, such as with
ASD, VSD or PIVA/PDA
Eisenmenger syndrome

68. These congenital anomalies cause an increase in
flow and higher right-sided pressures, which lead
to compensatory RV hypertrophy and a
subsequent rise in PA pressure
Increasing PHT leads to equalisation of pressures
either side of the shunt but, at some point, the
right sided pressures will exceed those on the left
side, resulting in shunt reversal, and desaturated
blood entering the left side of the circulation
Pathophysiology

69. Pathophysiology

70. New onset of cyanosis and SOB are the
most common clinical features, in pts.
with known acyanotic CHD
Clinical features

71. Closure of the shunt is contraindicated if PHT
is irreversible because the right-to left shunt
now serves to decompress the pulmonary
circulation
Combined heart-lung transplantation is still
sometimes performed
Treatment

72. Heart-Lung Transplantation