From the Guidelines
Tetralogy of Fallot with Pulmonary Atresia (TOF-PA) manifests as a severe congenital heart defect with key features including a ventricular septal defect (VSD), overriding aorta, right ventricular hypertrophy, and complete obstruction of the pulmonary valve (pulmonary atresia). The clinical presentation of TOF-PA is characterized by cyanosis, hypoxic spells, poor feeding, failure to thrive, and clubbing of fingers and toes in older children, as a result of poor oxygenation due to the complete obstruction of pulmonary blood flow 1.
Key Features
- Ventricular septal defect (VSD)
- Overriding aorta
- Right ventricular hypertrophy
- Complete obstruction of the pulmonary valve (pulmonary atresia)
Clinical Presentation
- Cyanosis (bluish discoloration) shortly after birth
- Hypoxic spells
- Poor feeding
- Failure to thrive
- Clubbing of fingers and toes in older children
- Single S2 heart sound and a continuous murmur if a patent ductus arteriosus is present
Diagnosis and Management
The condition is often diagnosed prenatally through ultrasound or postnatally with echocardiography, and blood tests typically show polycythemia (increased red blood cells) as a compensatory mechanism 1. Immediate management with prostaglandin E1 infusion is crucial to maintain ductal patency until surgical intervention. Surgical correction involves multiple staged procedures, beginning with establishing reliable pulmonary blood flow through shunts or conduits, followed by complete repair including VSD closure and right ventricular outflow tract reconstruction, as outlined in the esc guidelines for the management of grown-up congenital heart disease 1.
Patterns of Pulmonary Atresia
There are three patterns of PAs:
- Unifocal with confluent good size PAs supplied by a PDA
- Multifocal, with confluent but hypoplastic PAs (‘seagull’ appearance) supplied by multiple major aortic pulmonary collaterals (MAPCAs)
- Multifocal with non-confluent PAs supplied by MAPCAs, which determine both clinical presentation and management 1.
From the Research
Manifestations of Tetralogy of Fallot with Pulmonary Atresia (TOF-PA)
The manifestations of TOF-PA are characterized by complete failure of forward flow from the right ventricle to the pulmonary arterial system, resulting in pulmonary blood flow being entirely dependent on shunting from the systemic circulation 2. This can occur via a patent ductus arteriosus, major aortopulmonary collaterals, or a combination of the two.
Pathophysiology
The pathophysiology of TOF-PA is largely attributable to the abnormalities of the pulmonary vasculature 2. Patients with TOF-PA have a higher risk of reinterventions to address pulmonary arterial or RV-pulmonary artery conduit stenosis, progressive aortic root dilation and aortic insufficiency, and late mortality than those with less severe forms of TOF 3.
Clinical Features
- Complete failure of forward flow from the right ventricle to the pulmonary arterial system
- Pulmonary blood flow entirely dependent on shunting from the systemic circulation
- Abnormalities of the pulmonary vasculature
- Higher risk of reinterventions and late mortality compared to less severe forms of TOF
Management
The goal of management is to establish pulmonary blood flow from the right ventricle with RV pressures that are ideally less than half of the systemic pressure to allow for closure of the ventricular septal defect 3. Surgical options for first-stage palliation include right ventricle to pulmonary artery connection and modified Blalock-Taussig shunt 4. The choice of surgical strategy depends on the individual patient's anatomy and physiology, and thorough evaluation of cardiac anomalies is recommended 5.
Outcomes
Outcomes for patients with TOF-PA have improved significantly with advances in surgical and interventional management, but there is ongoing debate about the optimal management strategy 2. Patients with TOF-PA remain at risk for pulmonary arterial stenoses and pulmonary hypertension even after operative correction 2.