Transcript TRICUSPID ATRESIA

TRICUSPID ATRESIA
Dr Vivek pillai
• 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 %.
HISTORY
• First reported by Kreysig in 1817.
• Clinical features reported by Bellet and
Stewart in 1933.
• Also by Taussig and Brown in 1936.
EMBRYOLOGY
• During early embryogenesis,the process of
expansion of the inlet portion of the right
ventricle coincides with development of the
AV valves.
• Failure of this process of inlet expansion is the
pathogenetic mechanism for the usual
muscular variety of tricuspid atresia.
• The less common variety , with well formed
but fused leaflets,occurs if the embryological
insult occurs later in gestation.
• If valve fusion is incomplete, tricuspid stenosis
develops.
ANATOMY
• The most common type of tricuspid atresia is
muscular .
• It is characterized by a dimple or a localized
fibrous thickening in the floor of the right
atrium at the expected site of the tricuspid
valve.
• The muscular variety constitutes 89% of cases.
• In the membranous type (6.6%), the
atrioventricular portion of the membranous
septum forms the floor of the right atrium at
the expected location of the tricuspid valve.
• This particular type appears to be associated
with absent pulmonary valve leaflets.
• Minute valvar cusps are fused together in the
valvar type (1%).
• In the Ebstein type (2.6%), fusion of the
tricuspid valve leaflets occurs; attachment is
displaced downward, and plastering of the
leaflets to the right ventricular wall occurs.
• 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.
• The right atrium is enlarged and
hypertrophied.
• An interatrial communication is necessary for
survival.
• This communication most commonly is a
stretched patent foramen ovale.
• A true ASD is much less common and when
present is almost always in the ostium
secundum location.
• Rarely, the patent foramen ovale is obstructive
and may form an aneurysm of the fossa ovalis,
which is sometimes large enough to produce
mitral inflow obstruction
• The left atrium may be enlarged, especially
when the pulmonary blood flow is increased.
• The mitral valve is morphologically normal; it
is rarely incompetent and has a large orifice.
• The left ventricle is enlarged and
hypertrophied but usually morphologically
normal
• The right ventricle is small and hypoplastic.
• In patients with a large VSD or TGA, the size
of the right ventricle may be larger, but, even
in these patients, the right ventricle is smaller
than normal.
VSD in tricuspid atresia
• Associated VSD is common with TA, seen in
about 90% of individuals during infancy.
• Is usually perimembranous but also may occur
in the muscular septum or as a component of
an atrioventricular septal defect, although the
latter is rare.
• At birth the VSD is usually
restrictive,permitting adequate but not
excessive pulmonary blood flow .
• This advantage is often lost, as 40% of these
defects close spontaneously/ decrease in size”acquired pulmonary atresia”
• The majority of defects close in the first yr of
life.
• These restrictive VSD’S cause subpulmonic
obstruction in pts with normally related great
arteries, and subaortic obstruction in pts with
TGA.
Classification
Proposed by Kuhne and later modified
Type 1 : normally related great arteries (70 –
80%)
a. intact ventricular septum with pulmonary
atresia( 9%)
b. small ventricular septal defect and
pulmonary stenosis( 51%)
c. large ventricular septal defect without
pulmonary stenosis ( 9%)
Type ii : D-transposition of great arteries (12 –
25%)
a. ventricular septal defect with pulmonary
atresia( 2%)
b. ventricular septal defect with pulmonary
stenosis( 8%)
c. ventricular septal defect without
pulmonary stenosis(18%)
Type 3 :L- Transposition or malposition of great
arteries (3-6%)
associated complex lesions, ie., truncus
arteriosus, endocardial cushion defect
ADDITIONAL CARDIOVASCULAR
ABNORMALITIES- 20%
• Coarctation of aorta – 8%
• Persistent left SVC
• Juxtaposition of atrial appendages-50% of TA
with TGA.
• Right aortic arch
• Abnormalities of mitral apparatus- cleft in
AML,malattachment of the valve,direct
attachment of the mitral leaflets to papillary
PHYSIOLOGY-TA WITH NRGA
• Obligatory rt to left shunt at atrial level.
• LA receives both the entire systemic and
pulmonary venous return.
• The entire mixture flows into the LV which is
the sole pumping chamber for the pulmonary
and systemic circulation.
• When the great arteries are normally
related,pulm artery blood flow is usually
reduced as the restrictive VSD, is a zone of
subpulmonic stenosis.
• LV overload is curtailed but at the cost of
cyanosis.
• This is so in 90% of cases.
In TGA
• The VSD is almost always non-restrictive and
pulmonary stenosis is usually absent.
• Low PVR results in abundant pulmonary
arterial blood flow.
• Minimal cyanosis,marked LV volume overload.
• If these pts have a restrictive vsd,or
infundibular narrowing→diminished syst
circulation→metabolic acidosis and shock.
SEX PREDILECTION
• Tr. Atresia with normally related great arteries
have an equal frequency in males and
females.
• If TGA is present→male preponderance.
• No male preponderance with juxtaposition of
atrial appendages.
GENETICS
• Although specific genetic causes of the
malformation remain to be determined in
humans, the FOG2 gene may be involved in
the process.
• This has however been validated only in
animal studies.
• Familial recurrence is low , and recurrence in
siblings is only about 1%.
OVERALL ACTUARIAL SURVIVAL IN
INFANTS WITH TRICUSPID ATRESIA
• 1 year- 72%.
• 5 years- 52%.
• 10 years- 46%
NATURAL HISTORY
• Few infants with tr. Atresia and normally
related gr . Arteries with an intact ventricular
septum survive beyond 6 months of age
without surgical palliation.
• Intense hypoxia and death ensue unless the
ductus is patent, or adequate systemic to PA
collaterals are present , either of which are
unlikely.
TR. ATRESIA WITH NRGA AND
SMALL VSD.
• The VSD in such patients closes
spontaneously or is excessively obstructive, so
that majority of patients die by one year.
• Rarely, a favorable balance is achieved b/w
the presence of VSD and pulm . Blood flow ,
permitting survival from 2nd to 5th decades.
TR. ATRESIA WITH NRGA AND
LARGE VSD.
• Pts with TA , normally related great arteries
and large VSD do not fare well
• Excessive pulmonary arterial flow results in
vol. overload of LV and CCF.
• Pts have lived to ages 4 to 6 years.
• In exceptional cases, long survivals have been
reported between ages 32 and 45 yrs.
TR. ATRESIA WITH TGA
• Same poor longevity patterns hold when TA
occurs with complete transposition and large
VSD.
• TA with TGA with subaortic stenosis(
restrictive VSD) is an ominous combination.
• Exceptional survivals to mid-late teens have
been recorder.
• problems related to increased longevityI.E,brain abscess, paradoxical embolism
Physical examination- appearance
• Dysmorphic facies-occasionally “cat-eye”
syndrome or congenital coloboma may
be seen.
JVP
• Increase in the A wave amplitude , due to the
restrictive interatrial communication.
• Y descent is slow
• In LVF, A and V waves increase in amplitude.
Precordium
• LV impulse without a RV impulse in a cyanotic
patient.
• A gentle RV impulse in pt with TA ,complete
transposition and a well dev RV .
• Palpable thrill if VSD is restrictive.
AUSCULTATION
• First heart sound is single .
• Second usually single, but a soft delayed
pulmonic component is occasionally present.
• TA with normally related great arteries,
prominent systolic murmur originates at the
site of restrictive VSD – holosystolic, maximal
at the mid to lower left sternal edge.
TA with complete transposition
and increased pulmonary blood
flow
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Holosystolic murmur – across VSD
S2 – single but always loud
S3
MDM
4th heart sounds are rare in any of the
varieties of tricuspid atresia.
Pulmonary vascular resistance –
high
• VSD murmur vanishes
• Soft midsystolic murmur- anterior aortic root
• Rarely, the loud second component from the
dilated hypertensive posterior pulmonary
trunk is heard.
• TA with complete transposition, coexisting
pulmonic or subpulmonic stenosis –
midsystolic murmur – loudness and length
vary inversely with degree of obstruction
ECG
• Tall peaked right atrial P waves are usually
seen
• Biatrial P – if left atrial volume is↑ due to
↑PBF.
• PR interval- normal.
• QRS axis – left and superior ( type 1 pts)
• Absence of RV forces in precordial leads
CHEST X-RAY-TA WITH NRGA AND
SMALL VSD
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Pulmonary vascularity reduced.
Pulmonary artery segment – inconspicuous.
Heart size – normal.
Right cardiac border, esp in LAO projection –
superior convexity caused by enlargement of
RA and its appendage.
• Inferior border – flat or receding owing to
absence of RV.
• LAO – Humped appearance of right cardiac
border and a prominent left cardiac silhouette
TA with complete transposition
and no obstruction
• Lungs – plethoric
• LV, LA, RA – enlarged
• Right cardiac border seldom has distinctive
hump-shaped contour – RV is relatively well
developed
Tr. Atresia with TGA
TA with complete transposition
and PS
• Pulmonary blood flow is normal or reduced
• Ascending aorta and pulmonary trunk are not
border forming (narrow vascular pedicle)
ECHOCARDIOGRAM
• Presence of an imperforate linear echo
density in the location of normal TV
• Presence of two great arteries and semilunar
valves
• Confirm the presence and size of the
interatrial communication.
• Confirm the presence of a VSD.
CARDIAC CATHETERIZATION
• Limited role at present.
• Therapeutic role for balloon atrial
septostomy.
• Prior to a Fontan for determining
pulm.vascular resistance.
HEMODYNAMIC DATA
• In infants, the right atrial pressure is slightly
higher than the left atrial pressure.
• prominent ‘a ‘wave in the right atrium,
especially if the interatrial communication is
restrictive.
• LV systolic and EDP – normal.
• LVEDP may increase in patients with large
VSD’s as PVR drops and left heart volume
overload , ensues.
INITIAL MEDICAL MANAGEMENT
• PGE1, should be started in neonates with
severe cyanosis to maintain patency of the
ductus before cardiac catheterization or
planned surgery
• Balloon atrial septostomy may be carried out
as part of the initial catheterization to improve
the RA-LA shunt.
SURGICAL CARE
• Surgical management may be broadly grouped
into palliative and corrective therapy.
PALLIATIVE SURGERY DECIDED IN
TERMS OF
• decreased pulmonary flow
• increased pulmonary flow
• intracardiac obstruction.
FOR ↓ PBF.
• Pulmonary blood flow may be increased by
surgical creation of an aortopulmonary shunt.
• subclavian artery to ipsilateral pulmonary
artery anastomosis by Blalock and Taussig in
1945
• Potts shunt (descending aorta–to–left
pulmonary artery anastomosis),
• Waterston-Cooley shunt (ascending aorta–
to–right pulmonary artery anastomosis
• central aortopulmonary fenestration or GoreTex shunt,
• modified Blalock-Taussig shunt (Gore-Tex
interposition graft between the subclavian
artery and the ipsilateral pulmonary artery),
• Glenn shunt (superior vena cava–to–right
pulmonary artery anastomosis, end-to-end),
↑ PBF
• In patients with tricuspid atresia type II ,
pulmonary artery banding should be
performed following stabilization with
anticongestive measures.
CORRECTIVE SURGERY
• Fontan and Kreutzer- initial description of the
physiologically corrective operation for
tricuspid atresia
• Complete separation of the systemic and
pulmonary circuits
CHOUSSAT CRITERIA
• Age at operation – 4 and 15 yrs( not strictly
followed nowadays)
• Normal sinus rhythm
• Normal systemic venous connections
• Normal right atrial size
• Normal pulmonary arterial mean pressure (
mean >= 15 mm Hg)
• Low pulmonary vasc resistance (4 woods
units/m2)
• Adequate sized pulm. Arteries with diameter
> 75% of aortic diameter.
• Normal LVEF (>60%)( rel. contraindication)
• Absence of MR( relative contraindication)
• Absence of complicating factors from prev
ious surgeries
EARLY COMPLICATIONS OF
FONTAN
LATE COMPLICATIONS OF
FONTAN
• Low cardiac output,heart
failure or both .
• Persistent pleural effusion.
• Thrombus formation in the
systemic venous pathways.
• Liver dysfunction
• Hepatomegaly and ascites.
• Supraventricular
arrythmias.
• Progressive decrease in
oxygen saturation( obstn. of
venous pathways, leakage
in intra- atrial baffle, dev of
pulm av fistula.).
• Protein losing enteropathy
• THANK YOU.