Tricuspid atresia is a congenital heart defect where the tricuspid valve is absent or not formed, preventing communication between the right atrium and right ventricle. It occurs in approximately 0.06 per 1000 live births with no gender predominance. The condition ranges in severity from complete absence of the tricuspid valve to stenosis. Early presentation includes severe cyanosis, hypoxemia, and acidosis in infants with low pulmonary blood flow, while those with higher flow present with heart failure symptoms later in infancy. Echocardiography can identify the absent tricuspid valve and associated defects. Without surgical intervention, few infants survive beyond 6 months, but current treatments including shunts and the

1. Tricuspid Atresia
Dina Abdelsalam .MD
Tanta University

2. • Defined as congenital absence or
agenesis of the tricuspid valve, with
no direct communication between the
right atrium and right ventricle.
• Incidence : 0.06 per 1000 live births
• Gender: There is no gender
predominance
patients with associated TGA —male to
female ratio was 2 : 1
• Prevalence :in clinical series of
congenital heart disease is 1- 2.4 %.

3. Embryology
The atrioventricular valves develop shortly after the
atrioventricular canal divides. (Days 34 to 36)
The tricuspid valve leaflets have several origins:
The septal leaflet :mostly develops from the inferior endocardial
cushion with a small contribution from the superior cushion.
The anterior and posterior leaflets:
develop by undermining of a skirt
of ventricular muscle tissue.
The process of undermining extends
until the atrioventricular valve junction
is reached.

5. • Defined as congenital absence or
agenesis of the tricuspid valve,
with no direct communication
between the right atrium and right
ventricle.
• Incidence : 0.06 per 1000 live
births
• Prevalence :in clinical series of
congenital heart disease is 1- 2.4
%.

6. Embryology
• Resorption of the muscle tissue produces normal-appearing valve
leaflets and chordae tendineae.
• Fusion of developing valve leaflet components results in stenosis
(partial fusion) or atresia (complete fusion) of the valve.
• Whether a muscular type of TA develops or whether well-formed
but fused tricuspid-valve leaflets develop depends on the stage of
development when the embryologic aberration takes place.

7. Embryology
• The classic muscular form of TA develops if the embryologic insult occurs early in
gestation, and fused valve leaflets occur if the embryologic abnormality occurs
slightly later than this in gestation.
• If the valve fusion is incomplete, stenosis of the tricuspid valve develops.
Therefore, the fact that isolated congenital tricuspid stenosis belongs to the
group of TA defects and that their embryologic developments are similar is no
surprise. Thus, the tricuspid valve stenosis, TA with well formed but fused valve
leaflets, and the muscular type of TA represent a spectrum of morphologic
abnormalities . The pathologic, clinical, and ECG features of tricuspid stenosis and
TA are similar

8. Classification
Tricuspid atresia is classified on the basis of:
• Valve Morphology
• Pulmonary Vascular markings
• and associated cardiac defects

9. Valve Morphology
• Mascular : common 89% dimpling or fibrous
thickenening
• Membranous : 6.6% with the atrioventricular portion
of the membranous septum forming the floor of RA
• Valvar: 1% fused cusps
• Ebstein:
• Unguarded with muscular shelf.
• The Atrioventricular canal type is extremely rare (0.2%).
-A leaflet of the common atrioventricular valve seals off
the only entrance into the right ventricle.

10. Heart specimen of a patient with
muscular type of tricuspid atresia.
Note dimple (arrow) in the floor of the
right atrium with muscle fibers radiating
around it. An atrial septal defect (ASD)
is also shown.

11. MEMBRANEOUS

12. VALVAR
1%
FUSED CUSPS

13. ASSOCIATED CARDIAC
DEFECT
GREAT ARTERY INTERRELATIONSHIP

14. Pathophysiology
ATRESIA OF TRICUSPID VALVE (type I)
• No communication between RA AND RV
RV is underdeveloped.
• Systemic venous blood received by RA
Enters LA through PFO or ASD Mixing of
systemic and pulmonary blood RA Enters
LV Blood enters RV through VSD From
RV blood enters Pulm trunk
• Blood enters pulm trunk via PDA
Increased pulmonary blood flow LA and
LV hypertrophy CHF

15. Pathophysiology
Type II (d-TGA)
the pulmonary blood flow is directly
derived from the LV. The systemic blood
flow is via the VSD and the RV.
Type III, subtype 1 (L- TGA)
the atretic morphologic tricuspid valve is a
left sided atrioventricular valve and
therefore, in a physiological sense, it
behaves as mitral (left ) obstruction.
In other type III and type IV patients,
the systemic and pulmonary blood flows
are determined by the size of the
VSD and other associated defects

16.  Pulmonary Outflow obstruction may be either
subvalvar or valvar in Patients with TGA,
while in Patients with normally related great arteries the
pulmonary Obstruction is often
• at the VSD level although, in a few cases,
• Subvalvar pulmonary stenosis,
• narrow tract of the hypoplastic Right ventricle
• and rarely, valvar pulmonary stenosis may Also be
responsible for pulmonary outflow tract obstruction.
 With pulmonary atresia, either a PDA or
Aortopulmonary collateral vessels may be present.

17. Decreased pulm flow 90%
• Severe cyanosis, hypoxemia, and acidosis
• LV apical impulse
Approximately one-half of the patients with
tricuspid atresia manifest symptoms on the 1st
day of life and 80 % would be symptomatic by the
end of the 1st month of life
The magnitude of pulmonary blood flow determines
the clinical features.
Two modes of presentation are recognized:
• those with decreased pulmonary blood flow
• those with increased pulmonary blood flow.

18. INCREASED PULM FLOW 10%
• may not appear cyanotic but may present with
signs of heart failure later in infancy
• pulmonary plethora present with symptoms of
dyspnea, fatigue, difficulty feeding, and
perspiration, which are suggestive of
congestive heart failure.
• Cyanosis is minimal

19. History
1. Cyanosis is usually severe from birth. Tachypnea
and poor feeding usually manifest.
2. History of hypoxic spells may be present in infants.
Physical examination
1. Cyanosis, either with or without clubbing, is always
present.
2. A systolic thrill is rarely palpable when associated
with PS.
CLINICAL MANIFESTATIONS

20. 3. Auscultations:
• The S2 is single.
• A grade 2 to 3/6 holosystolic (or early systolic)
murmur of VSD is usually present
• At the lower left sternal border. A continuous
murmur of PDA is occasionally present. An apical
• Diastolic rumble is rarely audible in patients with
large PBF.
4. Hepatomegaly may indicate an inadequate
interatrial communication or CHF.

21. ELECTROCARDIOGRAPHY
1. “Superior” QRS axis (between 0 and –90 degrees) is
characteristic. It appears in most patients without TGA
and in only 50% of patients with TGA.
2. LVH is usually present; RAH or biatrial hypertrophy (BAH)
is common
X-ray Studies
The heart size is normal or slightly increased, with
enlargement of the RA and LV. Pulmonary vascularity
decreases in most patients although it may increase in
infants with TGA.
Occasionally, the concave PA segment may produce a
boot-shaped heart, like the x-ray findings of TOF.

25. ECHOCARDIOGRAPHY.
Two-dimensional :
• Absence of the tricuspid orifice, marked hypoplasia of the
RV, and a large LV can be imaged in the apical four-chamber
view.
• 2. The bulging of the atrial septum toward the left and the
size of the interatrial communication are easily imaged in the
subcostal four-chamber view.
• In the most common muscular type, a dense band of echoes
is seen at the site, where tricuspid valve should be and the
anterior leaflet of the detectable atrioventricular valve is
attached to the left side of interatrial septum Apical and
subcostal four-chambered views are best to demonstrate The
anatomy
• 3. The size of the VSD, the presence and severity of PS, and
the presence of TGA should all be investigated.
• 4. Patients with TGA should be examined for possible

26. ECHOCARDIOGRAPHY.

27. EECHOCARDIOGRAPHY

29. ECHOCARDIOGRAPHY.
M-mode echocardiographic features
• Large LA (usually proportional to the magnitude of
pulmonary blood flow)
• Dilated LV
• Normal to decreased LV FS%.
• A large posterior atrioventricular valve in
continuity with posterior semilunar valve
• and a small RV.
• The pulmonary valve may or may not be recorded.
• The tricuspid valve is conspicuously absent.
• Tricuspid valve-like echoes of low amplitude may
be recorded occasionally and this should not
exclude the diagnosis of tricuspid atresia.

30. OTHER LABORATORY STUDIES
Pulse oximeter and blood gas values are useful in quantitating
the degree of hypoxemia, thereby indicating the severity of
pulmonary oligemia.
Hemoglobin and hematocrit values are useful in children; the
degree of polycythemia is useful in estimating the severity of
hypoxemia.
Magnetic resonance imaging (MRI) and computed tomography
(CT) scan

33. with modified Fontan repair. The Fontan conduit (white arrow) runs from th
atrium (A) around the front of the heart towards the pulmonary artery. Note
front of the heart is identified by the anterior atrioventricular sulcus tissue
containing the signal void of the right coronary artery (black arrow

34. CARDIAC CATHETRIZATION
The diagnosis of tricuspid atresia based on clinical,
electrocardiographic and echocardiographic features is relatively
simple and cardiac catheterization rarely, if ever, are essential for
establishing the diagnosis.
Catheterization may be indicated prior to bidirectional Glenn or
Fontan
operations.

35. NATURAL HISTORY
1. Few infants with tricuspid atresia and normally related great
arteries survive beyond 6 months of age without surgical
palliation.
2. Occasionally, patients with increased PBF develop CHF and
eventually pulmonary vascular obstructive disease.
3. For patients who survive into their second decade of life
without a Fontan-type operation, the chronic volume overload of
the LV usually produces secondary cardiomyopathy and reduced
contractility of that ventricle.
(A Fontan procedure should be performed before LV dysfunction
develops.)

36. Management
Physiologically ‘corrective’ surgery for tricuspid
atresia and their modifications have improved
the prognosis of patients with tricuspid atresia.
Such physiologic correction is usually
performed in patients older than 2 years.
most tricuspid atresia patients manifest
symptoms in the neonatal period and should be
effectively palliated to enable them to reach the
age at which surgical correction could be
undertaken.

37. Medical management at the time of initial
presentation
• Infants with low arterial PO2 and decreased oxygen saturation
may be ductal dependent and therefore, the ductus should be
kept open by intravenous administration of prostaglandin
E1(PGE1)
• Dose of 0.05 -0.1 μg /kg/min
• The Rashkind procedure (balloon atrial septostomy) may be
performed as part of the initial catheterization to improve the RA-
to-LA shunt, especially when the interatrial communication is
considered inadequate by echo studies.
• Anticongestive measures in patients with CHF.

38. RASHKIND BALLOON ATRIAL
SEPTOSTOMY.

39. • Patients with associated severe coarctation of the
aorta may also be helped with PGE1 infusion; this
should be followed by surgical relief of
coarctation. Alternatively, balloon angioplasty may
be utilized to relieve the aortic obstruction.
• Infants with normally related great arteries and
adequate PBF through a VSD do not need any
other Procedures; rather, they need to be closely
watched for decreasing oxygen saturation
resulting from Spontaneous reduction of the VSD.

40. Palliative treatment of specific physiologic
abnormalities
Most infants with TA require one or more
palliative procedures before a Fontan-type
operation, the definitive surgery, can be
performed.
Staged palliative surgical procedures are aimed
at producing ideal candidates for a future Fontan
procedure. who have;
• Normal LV function
• and Low pulmonary resistance

41. 1. Normal LV function :
a.Preventing excessive volume load by using a relatively
small systemic-to-pulmonary shunt (e.g., 3.5 mm for
neonates).
b. Avoiding ventricular hypertrophy (for example, by
relieving outflow obstruction).
2. Low pulmonary resistance:
a. Providing adequate PBF that promotes the growth of
PA branches
b. Preventing distortion of the central pulmonary
arteries. A shunt operation is preferably done on the
right PA, which can be incorporated into the Fontan
operation.

42. DECREASED PULMONARY FLOW
• Systemic to pulmonary artery shunt:
Surgically created left to right shunt at the great
vessel level
• formalin infiltration of the ductal wall; stenting the
ductus arteriosus and enlarging the VSD.

43. Classic Blalock-Taussig shunt
Subclavian artery-to-ipsilateral pulmonary artery

44. Modified Blalock-
Taussig shunt
Gortex interposition
graft

45. Central shunt
Gortex interposition graft
between aorta and main
pulmonary artery

46. Potts
Direct anastomosis descending aorta to left pulmonary artery

47. Direct anastomosis ascending aorta to right
pulmonary artery

48. Increased pulmonary blood flow
Only type Ic and Type IIc patients,
i.e. without associated pulmonary stenosis, will fall
into the category of pulmonary plethora. A majority
of these patients will have type II anatomy and will
usually manifest during early infancy.
Pulmonary artery banding

49. Intracardiac obstruction
Intracardiac obstruction can occur at two different levels,
namely, patent foramen ovale and VSD.
Interatrial obstruction: Balloon atrial septostomy, if
unsuccessful blade atrial septostomy, and rarely surgical atrial
septostomy may be necessary to relieve the obstruction.

50. Interventricular obstruction:
Spontaneous closure of the VSD causing severe pulmonary
oligemia in type I patients and subaortic obstruction in type II
patients
The obstruction must be tackled at the time of either a
bidirectional Glenn or a modified Fontan operation.
Resection of the conal muscular septum, thus enlarging the
VSD, is a direct approach
Alternatively, the VSD, right ventricle and aortic valve may be
bypassed by anastomosis of the proximal stump of the
divided pulmonary artery to the ascending aorta (Damus-
Kaye-Stansel) at the time of bidirectional Glenn (or Fontan)
operation

51. Stage I. One of the following procedures is done in
preparation for a future Fontan operation:
1. Blalock-Taussig shunt, when PBF is small
2. PA banding, when PBF is excessive
3. Damus-Kaye-Stansel plus shunt operation (for TA
+ TGA + restrictive VSD)
Medical follow-up after stage I. Watch for:
a. Cyanosis (O2 saturation <75%)—cardiac
catheterization or MRI to find out its cause.
b. Poor weight gain (CHF from too much PBF)—
tightening of PA band may be necessary.
Fontan pathway

52. • Stage II (at 3 months or by 6 months).
• 1. BDG operation (an end-to-side SVC-to-RPA
shunt) also called bidirectional superior
cavopulmonary shunt)or
• 2. The hemi-fontan operation
Medical follow-up after stage II. Watch for the
following:
• A. A gradual decrease in O2 saturation (<75%) .
• B. Transient hypertension—1 to 2 weeks
postoperatively
Cardiac catheterization by 12 months after stage II

53. Bidirectional Glenn

54. Hemifontan

55. • Stage III ( fontan operation)
within 1 to 2 years after stage II operation.
• 1. “Lateral tunnel” fontan (with 4 mm fenestration)
Intracardiac total cavopulmonary connection
• 2. An extracardiac conduit (with or without
fenestration) extracardiac total cavopulmonary
connection

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