This document discusses the embryology, anatomy, clinical presentation, evaluation, and surgical treatment of pulmonary atresia with ventricular septal defect (PA-VSD). Some key points: - PA-VSD is characterized by atresia of the pulmonary artery and a ventricular septal defect, with pulmonary blood flow derived from collateral arteries. - Pulmonary blood supply can be unifocal from sources like a patent ductus arteriosus or multifocal from multiple aortopulmonary collateral arteries. - Surgical repair aims to connect as many lung segments as possible to right ventricular outflow during infancy to avoid pulmonary vascular changes, with the ultimate goal of complete repair closing all defects and incorporating

1. Pulmonary atresia with
Ventricular septal defect

2. tetralogy of Fallot = pulmonary arterial
supply is derived from sys-to-pul
collateral arteries

3. • extreme form of classic Tetralogy of
Fallot.

4. • Type IV truncus and Pseudotruncus.
•

5. Embryology
Development of PA
• MPA -septation of the truncus and aortic sac.
• Intrapericardial RPA and LPA -sixth aortic arches with
contribution from the aortic sac.
• intraparenchymal pulmonary arteries - vascular
plexuses of the lung buds.
• Vascular plexuses =intersegmental arteries (ISAs) in the
early embryonic period.

6. Embryology

7. Embryology
• cephalad malalignment of the infundibular septum=
anatomic obstruction of RVOT and a malalignment-type
of VSD
• aorta overrides VSD and is rotated in a counter-
clockwise direction

8. Embryology
• Pulmonary ostium becomses atretic much
earlier in development , shortly after
truncoconal partitioning but before closure of
ventricular septum.
▫ PUL CIRCULATION is so heterogenous and
highly variable with MAPCAS
• PA-IVS-- PA Occurs much later after cardiac
septation
▫ PDA, MPA, Confluent BPA, are well developed. No
MAPCAS.

9. Environmental Factors
• Maternal diabetes
• Maternal PKU
• retinoic acids
• trimethadione

10. Epidemiology
• 1.4% of CHD
• 0.07 per 100 live births.
• 26% - chromosomal abnormality/syndrome/single
organ defects

11. DiGeorge syndrome and associated with Chromosome
22q11 microdeletion.
▫ VACTER
▫ CHARGE
▫ Alagille

12. 22q11 deletion
• 10% -PA-VSD .
• Right aortic arch, or aberrant subclavian artery -MC
• Branch pulmonary arteries are smaller

13. NATURAL HISTORY
• depends on the adequacy of pulmonary blood flow
• duct-mediated pulmonary circulation -early mortality
due ductal constriction and closure.
• Half = die by 6 months
• 90% die by 1 year of age

14. Adequate pulmonary blood flow - greater longevity
Survival in to the sixth decade = multiple
aortopulmonary collaterals.

15. median age at death = 11 months(9 days to 30 years)
• 66% -alive at age 6 months
• 50% alive by 1 year
• 8% alive at age 10 years.

16. Pulmonary blood supply
• RVOT-Infundibular atresia/ annular atresia
• Extent of MPA atresia
• Native pulmonary arteries
• Source of pul blood
▫ PDA
▫ MAPCA
▫ Aquired collaterals
▫ AP window
• Distal pulmonary vascular arborization

17. RVOT
• Infundibular atresia- 70%
•

18. RVOT
• Anular aresia- thick fibrous membrane (analog
of the pulmonary valve)

19. MPA
• Extent of pulmonary valve atresia varies from
only a plate-like atresia of the pulmonary valve
to absence of both valve and a variable length of
MPA.
• Extension of MPA atresia to its bifurcation
results in non-confluent central pulmonary
arteries (PAs).

21. Right and Left Pulmonary Arteries
• Presence or absence of confluent PAs =
influences surgical outcome.
• 20% to 30% == nonconfluent RPAs and LPAs.
• Absence of the central portion of one or both of
these arteries.
• Confluent RPA and LPA - patent or atretic PT

22. PA Stenosis
Stenoses of Origins of Pulmonary Arteries
• confluence of the BPA and normal
arborization of pulmonary arteries- 10% have
stenosis of RPA, and 20% have stenosis of the
LPA.
• Stenoses are MC at the origin of PA on the side
of PDA
• juxtaductal stenoses (pulmonary artery
coarctations) - 65%

23. PA Stenosis
Stenoses beyond the origins of PA
• small percentage
• Localized areas of non compliance
• May not present as stenoses until after a
procedure that increases PBF

24. Somerville classification

26. Arborization of Pulmonary Arteries
• frequent failure of the pulmonary arteries to
distribute to all 20 pulmonary vascular
segments.
• Effected by
▫ Confluent central portions of pul arteries.
▫ Presence or absence of a PDA.
• Pulmonary arterial segments that are not
connected to a central pulmonary artery usually
receive large AP collateral arteries.

27.  complete vascular distribution from native pulmonary arteries to 18
lung segments (considered to be complete arborization

28. inverse correlation between the number of lung segments supplied by collaterals and those
supplied by the native PA.

29. Alternative Source of pulmonary blood
▫ PDA
▫ MAPCA
▫ Aquired collaterals
▫ AP window

30. PDA
• undersurface of the arch -67%
• undersurface of the innominate artery=33%
• PDA = S shaped, long and arises at an acute angle from
Aorta
• Unilateral PDA =confluent Pas
• PDA bilateral -- non-confluent PAs

31. • When PDA is present, PAs are confluent in 80% of cases.
• PDA is absent in 1/3 of cases and is associated
with absent central PAs.

32. Aortopulmonary collaterals (APCs)
• differentiate them from the bronchial arteries
• muscular arteries until they enter the lung parenchyma,
the muscular layer is gradually replaced by elastic lamina
that resembles true pulmonary arteries.
• 30 – 65%
• 2 – 6 in number.

33. Large Aortopulmonary Collateral Arteries
• “large” -embryologic rather than acquired origin
of the collaterals.
• join an interlobar or intra-lobar pulmonary
artery that arborizes normally within a pul-
monary lobe or segment

34. origin of APCs include
▫ upper or mid-descending thoracic aorta= MC
▫ subclavian arteries
▫ abdominal aorta
▫ coronary arteries.

35. Three types of SCAs
• Type I: Bronchial artery branches- from normal
bronchial arteries.
• Type II: Direct aortic branches- descending thoracic
aorta.
• Type III. Indirect aortic branches- from branches of the
aorta other than bronchial artery-subclavian, IMA and
intercostal arteries.

37. Morphology of Pulmonary Arterial Supply
• Unifocal
• Multifocal

38. Unifocal
• If all intrapulmonary arteries are connected to
unobstructed and confluent intrapericardial
pulmonary arteries
• confluence typically supplies all of both lungs

39. Unifocal
• persistent PDA that provides unifocal PBF
• rare for confluent pulmonary arteries feeding all
of both lungs to be supplied by a solitary
systemic-to-pulmonary collateral artery.
• rare cases- APW , or via a fistula from the
coronary arteries.

40. Multifocal
• different parts of one lung are supplied from
more than one source,
• clinical complexity

41. Multifocal
• multiple vessels feeding the pulmonary
parenchyma - systemic-to-pulmonary collateral
arteries.
• hardly ever feed a lung that also receives supply
via the PDA.

44. Various patterns of pulmonary arterial
anatomy and source of blood supply

45. • PDA -- less reliable source beyond the first few days of
life due to its tendency to close.
• APCs are also prone for stenosis over a period of weeks
to months but are more reliable than PDA

46. PDA VS MAPCAS PDA MAPCA’s
ORGIN Opposite to LSCA DTA
COURSE STRAIGHT TORTOUS/RETRO
ESOPHAGEAL
BRANCHING NO BRANCHING
STENOSIS PA end AORTIC END
DESTINY CENTRAL PA JOIN PA at HILUM /
LOBAR/SEGMENTAL

47. Congenital Heart Surgeons Society Classification
• Type A: Native PAs present, pulmonary vascular
supply through PDA and no APCs.
• Type B: Native PAs and APCs present
• Type C: No native PAs, pulmonary blood supply
through APCs only.

49. Coronary arteries
• origin and distribution = normal
• Conus artery =prominent.
▫ high origin of the coronary ostia,
▫ coronary-to-pulmonary artery fistulas,
▫ origin of the RCA from the left anterior aortic
sinus, coursing across RV infundibulum

50. Clinical Features
• cyanotic newborn
• becomes increasingly hypoxemic as the ductus
constricts.
• If the ductus arteriosus remains patent or because
systemic collateral vessels are sufficiently developed to
provide adequate PBF -not severely hypoxemic.

51. • Hypoxemia and cyanosis increase as the patient
“outgrows” the relatively fixed sources of PBF
• If growth is delayed- 22q11.2 microdeletion.
(growth failure due to heart failure caused by excessive
pulmonary blood flow is uncommon)

52. Modes of presentation
Cyanosis - 50%
HF– 25%
Murmur with mild cyanosis – 25%

53. Peripheral pulses
• normal in the neonatal period(even with a PDA)
• 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.

54. • normal S1
• single S2
• systolic murmur – LLSB
• not more than grade 3/6 in intensity
• RVOT is atretic- no separate loud systolic ejection
murmur at the upper left sternal border -

55. • PDA -continuous murmur after the first 4 to 6 weeks of
life.
• If MAPCA are present, continuous murmurs -multiple
and prominent over the back
(originate from the descending aorta)

56. ECG
• RVH
• RAD
• Increased PBF---Bi BVHand left LAE

57. CXR
• coeur en sabot
▫ levorotation of the heart, a prominent upturned
cardiac apex, secondary to RVH
▫ concavity in the region of the MPA
• right-sided aortic arch -(26% to 50% of these patients)
;TOF (20% to 25%).

58. • Pulmonary vascular markings - reticular pattern when
there are multiple collaterals supplying the lungs.
• Extent of pulmonary vascular markings will depend on
the extent of PBF

59. Echocardiographic Features
• PLAX-- large aortic valve that overrides a malaligned
VSD
• infundibular portion of the ventricular septum is
anteriorly malpositioned.
• TOF - patent, although hypoplastic, RVOT anterior to
the infundibular septum with continuity with the main
pulmonary artery.
• infundibular septum is fused with the free wall

62. • 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.)

63. • Suprasternal notch and high parasternal windows - size
and status of the proximal PA.
• malalignment VSD-membranous or infundibular
• ASDs and additional muscular VSDs

64. • Short-axis parasternal and subcostal views- coronary
artery abnormalities .
• Color flow -right ventricular to pulmonary artery
conduits

65. Cardiac Catheterization and Angiography
• size and distribution of the true pulmonary arteries
• extent of collateral blood supply

66. • large VSD- RV pressure is equal to LV pressure.
• RVOT is atretic - catheter will not enter the pulmonary
arteries from RV (manipulated from RV through the
VSD into the aorta.)
• Widened pulse pressure -large runoff into the lungs
through a PDA or a previously constructed shunt.

67. • Ventricular and aortic root angiography
• LV Ventriculography -LAXO view= middle portion and
most of the upper interventricular septum tangentially.
• Coronary artery anatomy -aortic root angiocardiogram
and a 70-degree left anterior oblique view (with 20
degrees of cranial angulation).

68. Surgical importance - origin of the left anterior
descending coronary artery from the right coronary
artery=5% of patients

69. • Selective injections in the systemic-to-pulmonary
collateral arteries -
▫ extent of the pulmonary arterial tree supplied by each
collateral vessel
▫ type of pulmonary artery connection
• 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)

70. • If the central native PAs were not identified on
echo- angiographically.
• simultaneous contrast injection into the
proximal stump of the pulmonary artery and the
pulmonary vein wedge injection - length of
discontinuity that need to be “bridged” surgically
during repair

71. CT / MR angiography
RVOT, MPA, branch PAs and APCs
Needs lesser contrast.

72. Evaluation of adequacy of
pulmonary arteries
• Complexity of pulmonary blood supply determines the
extent of surgical exploration necessary to perform
unifocalization
• Eligibility for complete repair - RV-PA conduit needs to
be placed to the vessel which is connected to maximum
possible pulmonary vascular bed
• Closing the VSD at the time of placement of RV – PA
conduit needs to be determined.

73. • Adequacy of the pulmonary vascular bed
• pulmonary vascular resistance
▫ determinants of postoperative RV pressure =
surgical outcome.

74. McGoon's ratio
• 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
• average value of 2.1 is normal
• Ratio above 1.2 -acceptable postoperative RV systolic
pressure
• .
• Ratio below 0.8 - inadequate for complete repair of PA
– VSD

75. Nakata index
• diameter of PAs measured immediately proximal to the
origin of upper lobe branches of the respective branch
Pas
• The sum of the cross sectional area (CSA) divided by the
body surface area of
• CSA of RPA (mm2)+ CSA of LPA (mm2)/ BSA (m2)
• >150 mm2/m2 =complete
repair without prior palliative shunt.

76. • Nakata index = widely used in preoperative assessment
of adequacy of pulmonary vascular bed
• Not useful in patients with multifocal pulmonary blood
supply, who are evaluated for single-stage repair of PA -
VSD.
• Nakata index= no provision for the additional vascular
bed that will be added by unifocalization

77. Total Neo-pulmonary artery index (TNPAI)
• APCs index
• addition of CSA of all significant APCs divided by the
BSA
• CSA of each APC is calculated from diameter of the
respective vessels measured on preoperative
cineangiogram

78. • sum of total APC index and PA index =TNPAI.
• TNPAI index >200 mm2/m2 = low postoperative RV/LV
pressure ratio and identified patients who were
candidates for VSD closure at the time of single-stage
surgicalrepair.

79. • limited value since they are based on the size of the
proximal vessels only.
• nature of the distal pulmonary vascular bed and
pulmonary vascular resistance are not expressed in these
calculations

80. Intraoperative method to assess the adequacy of
pulmonary vascular bed

81. General principles of surgical
therapy of PA-VSD
• 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

82. • ultimate goal - complete repair
• closure of all septal defects,
• interruption of all extracardiac sources of pulmonary
arterial blood flow
• incorporation of at least 14 pulmonary arterial segments
in a connection to RV
• central pulmonary artery size should be at least 50% of
normal.

83. • At the end of operation, RVSP should be <70%
that measured in LV
• If higher, the ventricular septal defect is
reopened.

84. • Complete repair - within weeks to months during
infancy.
• Therapeutic catheterization - balloon angioplasty help to
rehabilitate pulmonary arteries with stenosis.

85. Components of surgical repair
Unifocalization of APCs
Placement of RV – PA conduit
VSD closure.
performed in one-stage/different operations depending
on the anatomy and institutional policy.

86. RV – PA conduit placement
• Cadaveric, cryopreserved homograft - right ventricle to
available central pulmonary arteries.
• 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

87. Unifocalization of APCs
Unifocalize significant APCs during the first 3 months of
life
• Median sternotomy - single stage repair
• multi stage surgical approach- unifocalization is done
through lateral thoracotomies.
• unifocalization- APCs are ligated at the origin and
mobilized to maximize their length .
• Anastomosed in the mediastinum and connected to RV-
PA conduit.

89. Aortic arch angiogram before (A) and main pulmonary
arteriogram (B)after 1-stage complete unifocalization

90. VSD closure
• at the time of initial repair / 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

91. Intraoperative method to assess the adequacy of
pulmonary vascular bed
• After completion of unifocalization and distal
anastamosis of RV - PA conduit
• perfusion cannula and a PA catheter are
inserted from the proximal end of the conduit
and left atrial vent is placed.
• conduit is connected to the bypass machine.
• bypass machine is run at increasing flow rates to
2.5 L/min/m2 and the PA pressure is monitored.
• .

92. • VSD is closed if the mean conduit pressure is
< 25 mmHg, and left open if it is higher.
• < 25mmhg - Predict PRV/LV <0.5 following
intracardiac repair

93. VSD closure
• Alternative strategy - closing VSD with a fenestrated
patch
• fenestration =closed later either by surgery or
transcatheter technique.
• VSD closure is deferred at initial repair- 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 .

94. Multi-stage versus single-stage
approach

95. dependent on :
▫ 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.

96. Multi-stage approach:
• 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.
• diminutive PAs, RV – PA continuity is established by
placing a RV – PA conduit

97. • VSD is typically left open at this first stage.
• Unifocalization of APCs
• subsequent surgery -
▫ VSD closure
▫ Relieve any residual RVOT obstruction
▫ Placement of a valved conduit.

98. Single-stage approach
• APCs unifocalization and cardiac repair
• median sternotomy

99. Comparison of outcome between
multi and single-stage repair
• Comparable

100. • Early 1-stage complete unifocalization ->90% of patients
with pulmonary atresia and MAPCAs, and yields good
functional results.
• Complete repair during the same operation - two thirds
of patients.
• survival 3 years after surgery - 80%, and but there is a
significant rate of reintervention.
Circulation. 2000; 101: 1826-1832

101. Outcome of surgical repair
• Early mortality - 4.5%
• Late mortality - 16%
• Ten- and 20-year survival - 86% and 75%
• Freedom from reoperation of 55%.

102. Perioperative complications
• Phrenic nerve injury-0.3 %
• Reoperation for bleed-3%
• Sepsis-5%
• Heart block-0.5%
• Pulmonary infarction-0.4%

103. Incremental Risk Factors for Death
• PA Abnormalities
• Age - > 5 to 8 years
• Higher postrepair PRV/LV
• Duration of CPB

104. Complementary role of
interventional catheterization
• Dilation of Distal stenosis within lung parenchyma
(inaccessible to the surgeon. )
• Coil occlusion of APCs
• Stent placement in RVOT
• Palliative stenting of stenotic APC’S

105. Long term sequelae
• palliative shunts- progressive cyanosis and
polycythemia
• AR
• Deterioration of conduit and valve function -- loss of
luminal diameter, calcification, peel formation
• PR -- worsens with RV dilatation and dysfunction

106. Pulmonary venous wedge angiogram
• TRUE PA in which there is low or no
demonstrable prograde flow like PA

107. • End hole catheter is advanced from LA into
pulmonary vein wedged forcefully, into distal
capillary bed.
• Shows pr wave of arterial contour.

108. • 0.3-0.4 cc/kg body weight of contrast material
injected over a two second period.
• forcefull hand injection/ by under pressure (less
than 100 PSI).
• Fallowed by 15ml of fush.
• Progressive more force.
• Until PA are visulized.

109. • Some times contrast extravasates into
sarrounding tissue including bronchus
• Pt may develop hemoptysis- self limiting

110. Use
• caliber of the parenchymal pulmonary arteries
• sizes at the hilum of the lung
• presence or absence of a mediastinal confluence
of pulmonary arteries.
• Pr of PA(Aproximate).

111. THANK YOU