Background
Pulmonary atresia with ventricular septal defect (PA-VSD) is a cyanotic congenital heart disease characterized by underdevelopment of the right ventricular (RV) outflow tract (ie, subpulmonary infundibulum) with atresia of the pulmonary valve, a large ventricular septal defect (VSD), and overriding of the aorta. In the past, this anomaly was termed pseudotruncus or truncus arterious type 4.
Pulmonary atresia with ventricular septal defect demonstrates a wide spectrum of severity, depending on the degree of pulmonary artery development. Pathologically, pulmonary atresia with ventricular septal defect is frequently considered the most severe end of the spectrum of tetralogy of Fallot (TOF), but whether pulmonary atresia with ventricular septal defect and TOF should be treated as two distinct entities is controversial. In patients with the standard type of TOF with pulmonary atresia, pulmonary arteries are usually normal in size with normal peripheral pulmonary arborization, which is unlike pulmonary atresia with ventricular septal defect. In addition, systemic-to-pulmonary collateral vessels are not as well developed in patients with TOF with pulmonary atresia as they are in patients with pulmonary atresia with ventricular septal defect.
Pathophysiology
In pulmonary atresia with ventricular septal defect, the extent of pulmonary artery development determines the clinical presentation and the surgical options available. Pulmonary artery atresia may be local only, with involvement of the pulmonary valve and the proximal portion of the pulmonary trunk, or it may involve a longer segment. The right and left pulmonary arteries may communicate freely (ie, confluence) or may not communicate (ie, nonconfluence). Pulmonary circulation may be supplied by a patent ductus arteriosus (PDA), systemic-to-pulmonary collaterals, or plexuses of bronchial and pleural arteries.
The pathology of intrapulmonary arteries depends on the pulmonary blood flow and the patency of the ductus. If the ductus is large and supplies confluent pulmonary arteries, the blood flow and the intrapulmonary arteries of both lungs are normal. If collaterals are multiple and the ductus is congenitally absent, abnormal intrapulmonary arborization (ie, stenosis of unbranched and intrapulmonary arteries) and pulmonary hypertension are present.
Collateral arteries most commonly arise from the thoracic aorta and less commonly arise from subclavian arteries, internal mammary arteries, intercostal arteries, or the abdominal aorta. Rarely, the collateral arteries arise from coronary arteries. In 60% of patients, the collateral arteries are stenosed at the aortic end or at intrapulmonary sites, and stenosis tends to progress over time.
The ventricular septal defect may be membranous or infundibular, is usually very large, and rarely is obstructed by membranous tissue. In 50% of patients, a secundum-type atrial septal defect (ASD) or a patent foramen ovale (PFO) is also present.
The RV and, to a lesser extent, the right atrium usually are moderately to markedly hypertrophied and dilated. The left atrium and left ventricle (LV) are usually normal. The coronary arteries are usually normal, although anomalies have been observed, such as a high origin of the coronary ostia, coronary artery–to–pulmonary artery fistulae, [1] and transposition anatomy with the right coronary artery originating from the left anterior aortic sinus and transversing the right ventricular infundibulum. Other associations include tricuspid atresia or stenosis, complete atrioventricular (AV) canal, complete or corrected transposition of the great arteries, left superior vena cava, anomalies of the coronary sinus, dextrocardia, and asplenia or polysplenia syndrome.
Classification
Pulmonary atresia with ventricular septal defect is classified based on the presence or absence of native pulmonary arteries and the presence or absence of main pulmonary collateral arteries, as follows [2] :
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Type A (unifocal with confluent, good-sized pulmonary arteries): Pulmonary blood flow is provided by native pulmonary arteries. Patency of the ductus maintains the pulmonary circulation.
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Type B (multifocal, with confluent but hypoplastic pulmonary arteries supplied by major aortopulmonary collateral arteries [MAPCAs]): Pulmonary blood flow is supplied by native pulmonary arteries and by MAPCAs. The native pulmonary arteries may be supplied by either a ductus and/or MAPCAs.
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Type C (multifocal wiht nonconfluent or absent pulmonary arteries supplied by MAPCAs): Pulmonary blood flow is provided by MAPCAs. Native pulmonary arteries are absent.
Etiology
Genetic factors are considered to be a contributing factor in that there is an increased risk of occurrence in siblings (2.5-3%) and in offspring of adults with tetralogy of Fallot (1.2-8.3%). [3] Microdeletion 22q11.2 is common (facial anomalies, nasal speech, and developmental delay). [2]
Associated syndromes include VATER syndrome (ie, vertebral anomalies, anal atresia, tracheoesophageal fistula, esophageal atresia, and renal anomalies), Alagille syndrome, DiGeorge syndrome (velocardiofacial syndrome), and trisomy 21. Tracheobroncial anomalies may be seen as well.
Epidemiology
The best estimates of the relative frequency of pulmonary atresia with ventricular septal defect are 2.5-3.4% of all congenital cardiac malformations with a prevalence of 0.07 per 1000 live births. [4, 5]
Pulmonary atresia with ventricular septal defect is slightly more prevalent in males than in females.
Prognosis
If pulmonary atresia with ventricular septal defect (PA-VSD) is left untreated, the prognosis is very poor. [6] An estimated half of young patients die by age 2 years. However, with appropriate treatment and follow-up, about 65% of infants alive at age 1 year survive beyond age 10 years. [6]
Prognosis appears to be good in patients in the absence of chromosomal or syndromal anomalies. [7] Repeat interventions because of recurrent stenoses appears to be significantly higher in infants who undergo stage repair compared sith single-stage complete repair. [7]
In a single-institution, retrospective study (2005-2016) of data from 90 children with PA-VSD (median age at diagnosis: 0.5 y; range: 0-13.8 y), of whom 88 underwent surgical intervention (complete repair, n = 32), survival at age 1 year was 95%; age 5 years, 83.7%; and age 10 years, 79.6%. [8] At median follow-up of 5.7 years, 17 patients (18.9%) had died. The presence of associated and anomalies and nonconfluent PAs were significant mortality risks.
Complications
Possible complications of pulmonary atresia with ventricular septal defect (PA-VSD) include the following [6] :
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Congestive heart failure
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Erythrocytosis as a result of chronic hypoxia
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Infective endocarditis secondary to aberrant blood flow
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Sepsis due to either infective endocarditis or poor development of the immune system
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Brain abscess
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Delayed growth and puberty
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Arrhythmias and sudden death
Patient Education
Patients may require repeated surgeries for a complete repair of pulmonary atresia with ventricular septal defect (PA-VSD). Educate family members regarding congenital heart disease and how to perform cardiopulmonary resuscitation (CPR). Genetic counseling for future pregnancies is necessary.
For patient education resources, see the Heart Health Center, as well as Tetralogy of Fallot and Ventricular Septal Defect.
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Pulmonary Atresia With Ventricular Septal Defect. Management algorithm for patients with pulmonary atresia with ventricular septal defect (PA-VSD) and major aortopulmonary collateral arteries (MAPCAs), based on the nature of pulmonary vascular supply. PAs = pulmomary arteries. Courtesy of Elsevier (Gupta A, Odim J, Levi D, Chang RK, Laks H. Staged repair of pulmonary atresia with ventricular septal defect and major aortopulmonary collateral arteries: Experience with 104 patients. J Thorac Cardiovasc Surg. 2003;126(6):1746–52).
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Pulmonary Atresia With Ventricular Septal Defect. Anteroposterior still image obtained from angiography in the aortic arch of a 3-week-old infant born with pulmonary atresia with ventricular septal defect (PA-VSD) who is receiving a prostaglandin E infusion. A patent ductus arteriosus (PDA) is seen supplying confluent branch pulmonary arteries. Courtesy of Dr Thomas Forbes.
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Pulmonary Atresia With Ventricular Septal Defect. Anteroposterior angiographic view in the aortic arch of a 3-week-old infant born with pulmonary atresia with ventricular septal defect (PA-VSD) who is receiving a prostaglandin E infusion. A patent ductus arteriosus (PDA) is seen supplying confluent branch pulmonary arteries. Courtesy of Dr Thomas Forbes.
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Pulmonary Atresia With Ventricular Septal Defect. Anteroposterior still image obtained from angiography in a 3.5-mm right modified Blalock–Taussig (BT) shunt in the previous patient at age 4 months. There is a patent BT shunt with mild proximal right upper lobe and right lower lobe branch stenoses. Courtesy of Dr Thomas Forbes.
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Pulmonary Atresia With Ventricular Septal Defect. Anteroposterior angiographic view in a 3.5-mm right modified Blalock–Taussig (BT) shunt in the previous patient at age 4 months. There is a patent BT shunt with mild proximal right upper lobe and right lower lobe branch stenoses. Courtesy of Dr Thomas Forbes.
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Pulmonary Atresia With Ventricular Septal Defect. Lateral still image obtained from angiography in the previous patient at age 21 months. The infant underwent Rastelli operation with placement of a 15-mm pulmonary homograft. In this image, there is free homograft insufficiency without stenosis. Courtesy of Dr Thomas Forbes.
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Pulmonary Atresia With Ventricular Septal Defect. Lateral angiographic view in the previous patient at age 21 months. The infant underwent Rastelli operation with placement of a 15-mm pulmonary homograft. The presence of free homograft insufficiency with no stenosis is observed. Courtesy of Dr Thomas Forbes.
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Pulmonary Atresia With Ventricular Septal Defect. Lateral still image obtained from angiography in a 7-year-old boy born with pulmonary atresia with ventricular septal defect (PA-VSD) who underwent Rastelli operation with a 17-mm right ventricle to pulmonary artery (RV-PA) homograft. There is mild proximal conduit stenosis and free conduit insufficiency. The right ventricle appears moderately dilated. Courtesy of Dr Thomas Forbes.
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Pulmonary Atresia With Ventricular Septal Defect. Lateral angiographic view in a 7-year-old boy born with pulmonary atresia with ventricular septal defect (PA-VSD) who underwent Rastelli operation with a 17-mm right ventricle to pulmonary artery (RV-PA) homograft. There is mild proximal conduit stenosis and free conduit insufficiency. The right ventricle appears moderately dilated. Courtesy of Dr Thomas Forbes.
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Pulmonary Atresia With Ventricular Septal Defect. Lateral still image from angiography in the previous patient at age 8 years following Melody valve placement in the prestented 17-mm right ventricle to pulmonary artery (RV-PA) homograft. The Melody valve appears in good position. There is no Melody valve insufficiency. Courtesy of Dr Thomas Forbes.
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Pulmonary Atresia With Ventricular Septal Defect. Lateral angiographic view in the previous patient at age 8 years following Melody valve placement in the prestented 17-mm right ventricle to pulmonary artery (RV-PA) homograft. The Melody valve appears in good position. There is no Melody valve insufficiency. Courtesy of Dr Thomas Forbes.
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Pulmonary Atresia With Ventricular Septal Defect. Left anterior oblique ventriculogram in a patient (same patient as in the next image) with pulmonary atresia with ventricular septal defect (PA-VSD). The angiogram shows the left and right ventricles with a large malalignment VSD between them. The only outflow from the heart is the aorta. No evidence of pulmonary blood flow is observed arising from the ventricles directly to the lungs. Asc Ao = ascending aorta; Desc Ao = descending aorta; LV = left ventricle; and RV = right ventricle.
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Pulmonary Atresia With Ventricular Septal Defect. Anteroposterior view of an aortogram in a patient (same patient as in the previous image) with pulmonary atresia with ventricular septal defect (PA-VSD). The pulmonary circulation is supplied by collateral vessels (Collaterals) that arise from the descending aorta (Desc Ao).
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Pulmonary Atresia With Ventricular Septal Defect. Short-axis parasternal view (1) and diagram (3) in a patient with pulmonary atresia and ventricular septal defect (PA-VSD). Short-axis parasternal view (2) and diagram (4) in a patient with normal anatomy. LA = left atrium; PA = pulmonary artery; PV = pulmonary valve; RA = right atrium; RV = right ventricle; and TR = tricuspid valve.
