2“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 DefectChristo I. Tchervenkov, MD, and Nathalie Roy, MDAnn Thorac Surg 2000;69:97-105
3“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”
4TOF, PA is a specific type of PA-VSD where the intracardiac malformation is more accurately defined.
5Other synonyms -Type IV truncus and Pseudotruncus. PA-VSD has been proposed by the International nomenclature committee of Congenital Heart Surgery Nomenclature and Database Project as a unifying term.
6Essence of tetralogy of Fallot with pulmonary atresia is cephalad malalignment of the infundibular septumCauses anatomic obstruction of the right ventricular outflow tract and a malalignment-type of ventricular septal defect.The aorta overrides the ventricular septal defect and is rotated in a counter-clockwise direction
7Embryologic origin of the main, right and left pulmonary arteries, and the intrapulmonary arteries.
8Embryologic origin of the main, right and left pulmonary arteries, and the intrapulmonary arteries. 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.
9Survival of patients with tetralogy of Fallot and pulmonary atresia depends on the adequacy of pulmonary blood flowPatients with a duct-mediated pulmonary circulation -early mortality due ductal constriction and closure.Half this group die by 6 months of age and 90% die by 1 year of ageKirklin JW, Barratt-Boyes BG. Ventricula septal defect with pulmonary stenosis or atresia. In: Cardiac Surgery, 2nd edn. New York: Churchill Livingstone, 1993; 861–1012.
10Adequate 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.
11The median age at death was 11 months, ranging from 9 days to 30 years. 66% of the patients are alive at age 6 months50% alive by 1 year8% alive at age 10 years.
12Various patterns of pulmonary arterial anatomy and source of blood supply
13Environmental Factors Maternal diabetesMaternal phenylketonuria (PKU)Maternal exposure to retinoic acids and to trimethadioneInfants of diabetic women.
14EpidemiologyBaltimore-Washington Infant Study3 (BWIS) recorded 4390 infants with cardiovascular malformations from 1981 – 1989.Tet-PA accounted for 1.4% of all forms of congenital heart disease and 0.07 per 100 live births.26% of the patients with PA-VSD had chromosomal abnormality, a recognizable syndrome, or other single organ defects
15PA-VSD occurs more often DiGeorge syndrome and associated with Chromosome 22q11 microdeletion.VACTERCHARGEAlagille
1622q11 deletion 10% of patients with a 22q11 deletion have PA-VSD . Right aortic arch, or aberrant subclavian artery -more frequentBranch pulmonary arteries are smaller in patients with a 22q11.2 deletion
17Congenital Heart Surgeons Society Classification Type A: Native PAs present, pulmonary vascular supply through PDA and no APCs.Type B: Native PAs and APCs presentType 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
19Type A pulmonary atresia with ventricular septal defect
20Type B pulmonary atresia with ventricular septal defect
21Type C pulmonary atresia with ventricular septal defect
22PDA in VSD,PAIn 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
23PDA can be bilateral with non-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
24Aortopulmonary collaterals (APCs) The term MAPCA(s) was first used by Macartney, Deverall and Scott to differentiate them from the bronchial arteriesAortopulmonary 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.
25Known sites of origin of APCs include descending thoracic aortasubclavian arteriesabdominal aortacoronary arteries.
26Three types of SCAsType I: Bronchial artery branches- arising from one of the normal bronchial arteries.Type Il: Direct aortic branches- arising directly from the descending thoracic aorta.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.
28PDA is considered a 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
29PDA VS MAPCAS PDA MAPCA’s ORGIN Opposite to LSCA DTA COURSE STRAIGHT TORTOUS/RETROESOPHAGEALBRANCHINGNOSTENOSISPA endAORTIC ENDDESTINYCENTRAL PAJOIN PA at HILUM / LOBAR/SEGMENTALFLOW IN CENTRAL PULMONARY ARTERIESRETROGRADEANTEGRADE
30Clinical Features 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
31Hypoxemia 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)
32Modes of presentation Cyanosis - 50% Heart failure – 25% Murmur with mild cyanosis – 25%
33Peripheral pulsesThe peripheral pulses and blood pressure usually are 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.
34There is a normal first heart sound and a single loud second heart sound. A systolic murmur may be audible along the lower left sternal border but usually is not more than grade 3/6 in intensity.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.
35If a PDA is present, a continuous murmur usually is heard after the first 4 to 6 weeks of life. If systemic-to-pulmonary collateral vessels are present, continuous murmurs can be heard-multiple and prominent over the back(originate from the descending aorta)
36Electrocardiographic Features Right ventricular hypertrophyRight-axis deviationIncreased pulmonary blood flow -combined ventricular hypertrophy and left atrial enlargement may occur.
37Radiographic Features 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.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%).
40Pulmonary vascular markings have a typical reticular pattern when there are multiple collaterals supplying the lungs.Extent of pulmonary vascular markings will depend on the extent of pulmonary blood flow.
41Echocardiographic Features Parasternal long-axis show a large aortic valve that overrides a malaligned VSD . The infundibular portion of the ventricular septum is anteriorly malpositioned.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.The infundibular septum is fused with the free wall in patients with PA-VSD, and there is no separate outflow from the right ventricle .
44Truncus arteriosus - resembles PA-VSD (in truncus arteriosus, the pulmonary arteries arise directly from the posterolateral aspect of the truncal root prior to the arch.)
45Suprasternal notch and high parasternal windows - provide important information about the size and status of the proximal pulmonary arteries.The position of the malalignment VSD, membranous or infundibular, can be determined.ASDs and additional muscular VSDs can be detected.
46Short-axis parasternal and subcostal views-detecting coronary artery abnormalities . Color flow imaging and continuous wave Doppler techniques -assessment of surgically created right ventricular to pulmonary artery conduits
47Cardiac Catheterization and Angiography Delineate the size and distribution of the true pulmonary arteries and to ascertain the extent of collateral blood supply to the lungs
48Because of the large VSD, RV pressure is equal to the left ventricle pressure. 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.)Widened pulse pressure may be present if there is a large runoff into the lungs through a PDA or a previously constructed shunt.
49Ventricular and aortic root angiography should be done 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.
50Coronary 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.
51Surgical importance - origin of the left anterior descending coronary artery from the right coronary artery, which occurs in approximately 5% of patients
52Angiographic delineation of the anatomy of pulmonary blood supply - Venous approach by crossing the VSDRetrograde arterial approachThe image should provide a large field of view, ideally visualizing both lung fields
53determine which type of pulmonary artery connection is present Selective injections in the systemic-to-pulmonary collateral arteries -to delineate the extent of the pulmonary arterial tree supplied by each collateral vesseldetermine which type of pulmonary artery connection is presentEvanescent 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)
55Aortogram demonstrates large pulmonary confluence
56Selective injection into a collateral artery arising from middle portion of descending thoracic aorta
57Pulmonary vein wedge angiogram demonstrating a hypoplastic pulmonary artery confluence
58CT / MR angiographyAlternative modality to define RVOT, MPA, branch PAs and APCsNeeds lesser contrast.
59Evaluation of adequacy of pulmonary arteries Complexity of pulmonary blood supply determines the extent of surgical exploration necessary to perform unifocalizationEligibility 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.Closing the VSD at the time of placement of RV – PA conduit needs to be determined.
60McGoon's ratioMcGoon's ratio is calculated by dividing the sum of the diameters of RPA (at the level of crossing the lateral marginof 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 TAOAn average value of 2.1 is normalRatio above acceptable postoperative RV systolic pressure in Tetralogy of Fallot.Ratio below inadequate for complete repair of PA – VSD
61Nakata indexNakata PA index is calculated from the 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) of right and left PAs is divided by the body surface area of the patientNakata index = CSA of RPA (mm2)+ CSA of LPA (mm2)/ BSA (m2)A Nakata index of >150 mm2/m2 is acceptable for completerepair without prior palliative shunt.
62Nakata index is 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.
63Total Neo-pulmonary artery index (TNPAI) APCs index was calculated by 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
64The 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:
65These indices are of limited value since they are based on the size of the proximal vessels only. The nature of the distal pulmonary vascular bed and pulmonary vascular resistance are not expressed in these calculations
66General 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
67Complete repair should be attempted within weeks to months during infancy. Therapeutic catheterization procedures such as balloon angioplasty help to rehabilitate pulmonary arteries with stenosis.
68Components of surgical repair Placement of RV – PA conduitUnifocalization of APCsVSD closure.These components are performed in one-stage, or at different operations depending on the anatomy and institutional policy.
69RV – PA conduit placement Cadaveric, cryopreserved homograft is used to connect right ventricle to available central pulmonary arteries.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
70Unifocalization of APCs Unifocalize significant APCs during the first 3 months of lifeMedian 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.
71Aortic arch angiogram before (A) and main pulmonary arteriogram (B)after 1-stage complete unifocalization
72VSD closureClosure 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.
73VSD closureAlternative 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:
75The choice between multi-stage and single-stage repair is dependent on various factors: Nature of PAs (small vs good size)Duct-dependent or collateral-dependent PBFStatus of APCsAvailability of surgical skills and results of the institution.
76Multi-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.With diminutive PAs, RV – PA continuity is established by placing a RV – PA conduit
77The VSD is typically left open at this first stage. Unifocalization of APCsA subsequent surgery -VSD closureRelieve any residual right ventricular outflow tract obstructionPlacement of a valved conduit.
80Definitive repair in a patient with a previous bilateral unifocalization
81Single-stage approach Attempts to perform APCs unifocalization and cardiac repair at the same operation, through median sternotomy
82Comparison of outcome between multi and single-stage repair 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: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:
83Early 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 ArteriesExperience 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, MDCirculation. 2000; 101:
84Outcome of surgical repair Early mortality %Late mortality - 16%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 alJ Thorac Cardiovasc Surg 2002;124:70-81
85Perioperative complications Phrenic nerve injury-0.3 %Reoperation for bleed-3%Sepsis-5%Heart block-0.5%Pulmonary infarction-0.4%
86Complementary role of interventional catheterization Dilation of Distal stenosis within lung parenchyma (inaccessible to the surgeon. )Coil occlusion of APCsStent placement in RVOTPalliative stenting of stenotic APC’S
87Long term sequelaePatients on palliative shunts, develop progressive cyanosis and polycythemiaAortic regurgitationDeterioration of conduit and valve function by loss of luminal diameter, calcification, peel formationPulmonary regurgitation worsens with RV dilatation and dysfunction