Transcript Slide 1

Pulmonary atresia with Ventricular septal defect
“Pulmonary atresia-ventricular septal defect is defined as a
group of congenital cardiac malformations in whom there
is lack of luminal continuity and absence of blood flow
from either ventricle and the pulmonary artery, in a
biventricular heart that has an opening or a hole in the
interventricular septum. ”
Congenital Heart Surgery Nomenclature and Database Project: Pulmonary
Atresia—Ventricular Septal Defect
Christo I. Tchervenkov, MD, and Nathalie Roy, MD
Ann Thorac Surg 2000;69:97-105
“Tetralogy of Fallot with Pulmonary atresia is a congenital
cardiac malformation, characterized by the extreme
underdevelopment of the right ventricular infundibulum
with marked anterior and leftward displacement of the
infundibular septum often fused with the anterior wall of
the right ventricle resulting in complete obstruction of
blood flow into the pulmonary artery and associated with a
large outlet, subaortic ventricular septal defect”
TOF, PA is a specific type of PA-VSD where the
intracardiac malformation is more accurately defined.
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Other synonyms -Type IV truncus and Pseudotruncus.
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PA-VSD has been proposed by the International
nomenclature committee of Congenital Heart Surgery
Nomenclature and Database Project as a unifying term.
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Essence of tetralogy of Fallot with pulmonary atresia is cephalad
malalignment of the infundibular septum
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Causes anatomic obstruction of the right ventricular outflow
tract and a malalignment-type of ventricular septal defect.
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The aorta overrides the ventricular septal defect and is rotated in
a counter-clockwise direction
Embryologic origin of the main, right
and left pulmonary arteries, and
the intrapulmonary arteries.
Embryologic origin of the main, right
and left pulmonary arteries, and
the intrapulmonary arteries.
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The main pulmonary artery (MPA) -septation of the truncus and
aortic sac.
Intrapericardial right (RPA) and left (LPA) pulmonary arteries sixth aortic arches with contribution from the aortic sac.
The intraparenchymal pulmonary arteries - from the vascular
plexuses of the lung buds.
Vascular plexuses are supplied by the intersegmental arteries
(ISAs) in the early embryonic period.
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Survival of patients with tetralogy of Fallot and pulmonary
atresia depends on the adequacy of pulmonary blood flow
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Patients with a duct-mediated pulmonary circulation -early
mortality due ductal constriction and closure.
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Half this group die by 6 months of age and 90% die by 1 year
of age
Kirklin JW, Barratt-Boyes BG. Ventricula septal defect with pulmonary stenosis or
atresia. In: Cardiac Surgery, 2nd edn. New York: Churchill Livingstone, 1993; 861–1012.
Adequate pulmonary blood flow - a greater longevity is seen.
Survival in to the sixth decade reported in unoperated patient
with pulmonary atresia, ventricular septal defect, and multiple
aortopulmonary collaterals.
The median age at death was 11 months, ranging from 9 days to
30 years.
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66% of the patients are alive at age 6 months
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50% alive by 1 year
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8% alive at age 10 years.
Various patterns of pulmonary arterial
anatomy and source of blood supply
Environmental Factors
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Maternal diabetes
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Maternal phenylketonuria (PKU)
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Maternal exposure to retinoic acids and to trimethadione
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Infants of diabetic women.
Epidemiology
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Baltimore-Washington Infant Study3 (BWIS) recorded 4390
infants with cardiovascular malformations from 1981 – 1989.
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Tet-PA accounted for 1.4% of all forms of congenital heart
disease and 0.07 per 100 live births.
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26% of the patients with PA-VSD had chromosomal
abnormality, a recognizable syndrome, or other single organ
defects
PA-VSD occurs more often
 DiGeorge syndrome and associated with Chromosome
22q11 microdeletion.
 VACTER
 CHARGE
 Alagille
22q11 deletion
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10% of patients with a 22q11 deletion have PA-VSD .
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Right aortic arch, or aberrant subclavian artery -more frequent
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Branch pulmonary arteries are smaller in patients with a 22q11.2
deletion
Congenital Heart Surgeons Society Classification
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Type A: Native PAs present, pulmonary vascular supply
through PDA and no APCs.
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Type B: Native PAs and APCs present
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Type C: No native PAs, pulmonary blood supply through
APCs only.
Tchervenkov CI, Roy N. Congenital heart disease nomenclature and database
project: Pulmonary atresia - ventricular septal defect. Ann Thoracic Surg 2000;
69:S97-S105
Type A pulmonary atresia with ventricular septal defect
Type B pulmonary atresia with ventricular septal defect
Type C pulmonary atresia with ventricular septal defect
PDA in VSD,PA
In PA-VSD, PDA typically originates from either the
undersurface of the arch (67%) or from the undersurface of the
innominate artery (33%).
PDA is S shaped, long and arises at an acute angle from Aorta
Unilateral PDA is usually associated with confluent PAs
PDA can be bilateral with non-confluent PAs.
When PDA is present, PAs are confluent in 80% of cases.
PDA is absent in 1/3 of cases
Aortopulmonary collaterals (APCs)
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The term MAPCA(s) was first used by Macartney, Deverall and
Scott to differentiate them from the bronchial arteries
Aortopulmonary collaterals (APCs) are muscular arteries until
they enter the lung parenchyma, the muscular layer is gradually
replaced by elastic lamina that resembles true pulmonary arteries.
APCs are seen in 30 – 65% of patients with PA - VSD and are
usually 2 – 6 in number.
Macartney F, Deverall P, Scott O. Haemodynamic characteristics of systemic
arterial blood supply to the lungs. Br Heart J 1973;35:28–37.
Known sites of origin of APCs include
 descending thoracic aorta
 subclavian arteries
 abdominal aorta
 coronary arteries.
Three types of SCAs
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Type I: Bronchial artery branches- arising from one of the
normal bronchial arteries.
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Type Il: Direct aortic branches- arising directly from the
descending thoracic aorta.
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Type III. Indirect aortic branches-branches arising from
branches of the aorta other than bronchial artery.
e.g:from subclavian, internal mammary and intercostal arteries.
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PDA is considered a less reliable source beyond the first few
days of life due to its tendency to close.
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APCs are also prone for stenosis over a period of weeks to
months but are more reliable than PDA
PDA VS MAPCAS
PDA
MAPCA’s
ORGIN
Opposite to LSCA
DTA
COURSE
STRAIGHT
TORTOUS/RETROESOPH
AGEAL
BRANCHING
NO
BRANCHING
STENOSIS
PA end
AORTIC END
DESTINY
CENTRAL PA
JOIN PA at HILUM /
LOBAR/SEGMENTAL
FLOW IN CENTRAL
PULMONARY ARTERIES
RETROGRADE
ANTEGRADE
Clinical Features
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PA-VSD presents as a cyanotic newborn
Infant becomes increasingly hypoxemic as the ductus constricts.
If the ductus arteriosus remains patent or because systemic
collateral vessels are sufficiently developed to provide adequate
pulmonary blood flow- not severely hypoxemic
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Hypoxemia and cyanosis increase as the patient “outgrows” the
relatively fixed sources of pulmonary blood flow.
If growth is delayed-suspect the presence of a 22q11.2
microdeletion.
(growth failure due to heart failure caused by excessive pulmonary
blood flow is uncommon)
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Modes of presentation
Cyanosis - 50%
Heart failure – 25%
Murmur with mild cyanosis – 25%
Peripheral pulses
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The peripheral pulses and blood pressure usually are normal in
the neonatal period(even with a PDA)
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Beyond the first 4 to 6 weeks of age - if pulmonary blood flow
is through a PDA or collaterals ,the pulses are bounding, and
only minimal cyanosis is present.
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There is a normal first heart sound and a single loud second
heart sound.
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A systolic murmur may be audible along the lower left sternal
border but usually is not more than grade 3/6 in intensity.
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The right ventricular outflow tract is atretic-no separate loud
systolic ejection murmur at the upper left sternal border -this is
in contrast to the finding in TOF with antegrade pulmonary
blood flow.
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If a PDA is present, a continuous murmur usually is heard after
the first 4 to 6 weeks of life.
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If systemic-to-pulmonary collateral vessels are present,
continuous murmurs can be heard-multiple and prominent over
the back
(originate from the descending aorta)
Electrocardiographic Features
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Right ventricular hypertrophy
Right-axis deviation
Increased pulmonary blood flow -combined ventricular
hypertrophy and left atrial enlargement may occur.
Radiographic Features
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Characteristic appearance likened to the shape of a boot (coeur
en sabot).
 levorotation of the heart, a prominent upturned cardiac apex,
secondary to right ventricular hypertrophy.
 concavity in the region of the main pulmonary artery
produced by underdevelopment of the subpulmonary
infundibulum.
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The frequency of a right-sided aortic arch is greater in patients
with PA-VSD (26% to 50% of these patients) than in those with
TOF (20% to 25%).
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Pulmonary vascular markings have a typical reticular pattern
when there are multiple collaterals supplying the lungs.
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Extent of pulmonary vascular markings will depend on the
extent of pulmonary blood flow.
Echocardiographic Features
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Parasternal long-axis show a large aortic valve that overrides a
malaligned VSD . The infundibular portion of the ventricular
septum is anteriorly malpositioned.
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Patient with TOF has a patent, although hypoplastic, right
ventricular outflow tract anterior to the infundibular septum.
This outflow tract is in continuity with the main pulmonary
artery.
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The infundibular septum is fused with the free wall in patients
with PA-VSD, and there is no separate outflow from the right
ventricle .
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Truncus arteriosus - resembles PA-VSD
(in truncus arteriosus, the pulmonary arteries arise directly from
the posterolateral aspect of the truncal root prior to the arch.)
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Suprasternal notch and high parasternal windows - provide
important information about the size and status of the proximal
pulmonary arteries.
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The position of the malalignment VSD, membranous or
infundibular, can be determined.
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ASDs and additional muscular VSDs can be detected.
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Short-axis parasternal and subcostal views-detecting coronary
artery abnormalities .
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Color flow imaging and continuous wave Doppler techniques assessment of surgically created right ventricular to pulmonary
artery conduits
Cardiac Catheterization and Angiography
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Delineate the size and distribution of the true pulmonary arteries
and to ascertain the extent of collateral blood supply to the lungs
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Because of the large VSD, RV pressure is equal to the left
ventricle pressure.
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Right ventricular outflow tract is atretic -the catheter will not
enter the pulmonary arteries from the right ventricle
(manipulated from the right ventricle through the VSD into the
aorta.)
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Widened pulse pressure may be present if there is a large runoff
into the lungs through a PDA or a previously constructed shunt.
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Ventricular and aortic root angiography should be done
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Ventriculography should be performed with an injection into
the left ventricular cavity while the cameras are positioned to
record a 70-degree left anterior oblique view with 20 degrees of
cranial angulation. This projection displays the middle portion
and most of the upper interventricular septum tangentially.
Coronary artery anatomy can be defined by an aortic root
angiocardiogram and a 70-degree left anterior oblique view (with
20 degrees of cranial angulation).
An improved angiographic projection (frontal x-ray tube is
caudally angled) -"laid-back" position of the image intensifier
and cine camera results in superior visualization of the coronary
arteries and their relation to the aorta and the pulmonary artery.
Surgical importance - origin of the left anterior descending
coronary artery from the right coronary artery, which occurs in
approximately 5% of patients
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Angiographic delineation of the anatomy of pulmonary blood
supply  Venous approach by crossing the VSD
 Retrograde arterial approach
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The image should provide a large field of view, ideally visualizing
both lung fields
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Selective injections in the systemic-to-pulmonary collateral
arteries  to delineate the extent of the pulmonary arterial tree supplied
by each collateral vessel
 determine which type of pulmonary artery connection is
present
Evanescent negative washout pattern -stream of unopacified
blood from a connecting pulmonary artery flowing into an area
of opacified pulmonary arterial tree(may be the only indication of
an existing communication)
Long-axis oblique view of left ventriculogram
Aortogram demonstrates large pulmonary confluence
Selective injection into a collateral artery arising from
middle portion of descending thoracic aorta
Pulmonary vein wedge angiogram demonstrating a
hypoplastic pulmonary artery confluence
CT / MR angiography
Alternative modality to define RVOT, MPA, branch
PAs and APCs
Needs lesser contrast.
Evaluation of adequacy of
pulmonary arteries
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Complexity of pulmonary blood supply determines the extent of
surgical exploration necessary to perform unifocalization
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Eligibility for complete repair is dependent as RV-PA conduit
needs to be placed to the vessel which is connected to maximum
possible pulmonary vascular bed.
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Closing the VSD at the time of placement of RV – PA conduit
needs to be determined.
McGoon's ratio
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McGoon's ratio is calculated by dividing the sum of the
diameters of RPA (at the level of crossing the lateral margin
of vertebral column on angiogram) and LPA (just proximal to its
upper lobe branch), divided by the diameter of aorta at the level
above the diaphragm
[D RPA + D LPA] / D TAO
An average value of 2.1 is normal
Ratio above 1.2 -acceptable postoperative RV systolic pressure
in Tetralogy of Fallot.
Ratio below 0.8 - inadequate for complete repair of PA – VSD
Nakata index
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Nakata PA index is calculated from the diameter of PAs
measured immediately proximal to the origin of upper lobe
branches of the respective branch PAs.
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The sum of the cross sectional area (CSA) of right and left PAs
is divided by the body surface area of the patient
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Nakata index = CSA of RPA (mm2)+ CSA of LPA (mm2)/
BSA (m2)
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A Nakata index of >150 mm2/m2 is acceptable for complete
repair without prior palliative shunt.
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Nakata index is widely used in preoperative assessment of
adequacy of pulmonary vascular bed
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Not useful in patients with multifocal pulmonary blood supply,
who are evaluated for single-stage repair of PA - VSD.
Total Neo-pulmonary artery index (TNPAI)
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APCs index was calculated by addition of CSA of all significant
APCs divided by the BSA.
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CSA of each APC is calculated from diameter of the respective
vessels measured on preoperative cineangiogram
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The sum of total APC index and PA index is called TNPAI.
A TNPAI index >200 mm2/m2 correlated well with low
postoperative RV/LV pressure ratio and identified patients who
were candidates for VSD closure at the time of single-stage
surgicalrepair.
Reddy MV, Petrossian E, McElhinney DB, Moore P, Teitel DF,
Hanley FL: One stage complete unifocalization in infants: When
should the ventricular septal defect be closed? J Thorac Cardiovasc
Surg 1997;113:858-868.
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These indices are of limited value since they are based on the
size of the proximal vessels only.
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The nature of the distal pulmonary vascular bed and pulmonary
vascular resistance are not expressed in these calculations
General principles of surgical
therapy of PA-VSD
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Connect as many lung segments as possible to the blood flow
from RV during early infancy - to avoid significant histologic
changes occurs in pulmonary vasculature
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Complete repair should be attempted within weeks to months
during infancy.
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Therapeutic catheterization procedures such as balloon
angioplasty help to rehabilitate pulmonary arteries with stenosis.
Components of surgical repair
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Placement of RV – PA conduit
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Unifocalization of APCs
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VSD closure.
These components are performed in one-stage, or at different
operations depending on the anatomy and institutional policy.
RV – PA conduit placement
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Cadaveric, cryopreserved homograft is used to connect right
ventricle to available central pulmonary arteries.
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In complex cases, where a central pulmonary artery is absent or
the pulmonary blood flow is multifocal, unifocalization of the
diminutive native pulmonary arteries and APCs will be
performed before RV – PA conduit is placed
Unifocalization of APCs
Unifocalize significant APCs during the first 3 months of life
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Median sternotomy is the preferred method especially if single
stage repair is planned.
In multi stage surgical approach, unifocalization is done through
lateral thoracotomies.
During unifocalization, APCs are ligated at the origin and
mobilized to maximize their length .
Anastomosed in the mediastinum and connected to RV-PA
conduit.
Aortic arch angiogram before (A) and main pulmonary
arteriogram (B)after 1-stage complete unifocalization
VSD closure
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Closure of VSD at the time of initial repair avoids the need for
further surgery.
If any concerns about the adequacy of the pulmonary vascular
bed -defer VSD closure.
Unrepaired VSD avoids supra-systemic RV pressure in the
immediate postoperative period by allowing RV to decompress
through the VSD.
VSD closure
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Alternative strategy - closing VSD with a fenestrated patch and
the fenestration can be closed later either by surgery or
transcatheter technique.
When VSD closure is deferred at initial repair, it is surgically
closed after 6 – 12 months- when left to right shunt is
established via the VSD with Qp/Qs exceeding 2:1 by catheter
evaluation .
Reddy MV, Petrossian E, McElhinney DB, Moore P, Teitel DF,
Hanley FL: One stage complete unifocalization in infants: When
should the ventricular septal defect be closed? J Thorac Cardiovasc
Surg 1997;113:858-868.
Multi-stage versus single-stage
approach
The choice between multi-stage and single-stage repair is
dependent on various factors:
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Nature of PAs (small vs good size)
Duct-dependent or collateral-dependent PBF
Status of APCs
Availability of surgical skills and results of the institution.
Multi-stage approach:
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Traditional approach - palliative shunt in patients with good
size, confluent central PA during neonatal period or early
infancy to relieve cyanosis and allow for growth of distal
pulmonary arteries.
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With diminutive PAs, RV – PA continuity is established by
placing a RV – PA conduit
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The VSD is typically left open at this first stage.
Unifocalization of APCs
A subsequent surgery  VSD closure
 Relieve any residual right ventricular outflow tract
obstruction
 Placement of a valved conduit.
Right Unifocalization
Left unifocalization
Definitive repair in
a patient with a previous bilateral unifocalization
Single-stage approach
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Attempts to perform APCs unifocalization and cardiac repair at
the same operation, through median sternotomy
Comparison of outcome between
multi and single-stage repair
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The ultimate results are comparable but patients in the single
stage group undergo one or two operations less than the patients
in multi-stage group do.
Tchervenkov CI, Salasidis G, Cecere R, Beland MJ, Jutras L, Paquet M,
Dobell ARC: One-stage midline unifocalization and complete repair in
infancy versus multiple-stage unifocalization followed by repair for complex
heart disease with major aortopulmonary collaterals. J Thorac Cardiovasc Surg
1997;114:727-737.
Murthy KS, Rao SG, Krishnanaik S, Coelho R,Krishnan US, Cherian KM:
Evolving surgical management for ventricular septal defect, pulmonary
atresia, and major aortopulmonary collateral arteries. Ann Thoracic Surg
1999;67:760-764.
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Early 1-stage complete unifocalization can be performed in
>90% of patients with pulmonary atresia and MAPCAs, and
yields good functional results.
Complete repair during the same operation is achieved in two
thirds of patients.
Actuarial survival 3 years after surgery is 80%, and but there is a
significant rate of reintervention.
Early and Intermediate Outcomes After Repair of Pulmonary Atresia With
Ventricular Septal Defect and Major Aortopulmonary Collateral Arteries
Experience With 85 Patients :V. Mohan Reddy, MD; Doff B. McElhinney, MD;
Zahid Amin, MD; Phillip Moore, MD; Andrew J. Parry, MD; David F. Teitel, MD;
Frank L. Hanley, MD
Circulation. 2000; 101: 1826-1832
Outcome of surgical repair
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Early mortality - 4.5%
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Late mortality - 16%
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Ten- and 20-year survival - 86% and 75%
Freedom from reoperation of 55%.
Early and long-term results of the surgical treatment of tetralogy of Fallot with
pulmonary atresia, with or without major aortopulmonary collateral arteries:
John M. Cho et al
J Thorac Cardiovasc Surg 2002;124:70-81
Perioperative complications
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Phrenic nerve injury-0.3 %
Reoperation for bleed-3%
Sepsis-5%
Heart block-0.5%
Pulmonary infarction-0.4%
Complementary role of
interventional catheterization
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Dilation of Distal stenosis within lung parenchyma
(inaccessible to the surgeon. )
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Coil occlusion of APCs
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Stent placement in RVOT
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Palliative stenting of stenotic APC’S
Long term sequelae
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Patients on palliative shunts, develop progressive cyanosis
and polycythemia
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Aortic regurgitation
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Deterioration of conduit and valve function by loss of
luminal diameter, calcification, peel formation
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Pulmonary regurgitation worsens with RV dilatation and
dysfunction
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