From the Guidelines
Pulmonary valve atresia is a severe variant of Tetralogy of Fallot (ToF) characterized by the complete obstruction of blood flow from the right ventricle to the pulmonary arteries due to a completely sealed pulmonary valve. This condition is distinct from classic ToF, where the pulmonary valve is narrowed (stenotic) rather than completely sealed (atretic) [ 1 ]. The key characteristics of ToF include subpulmonary infundibular stenosis, a ventricular septal defect (VSD), an aorta that overrides the VSD, and right ventricular hypertrophy [ 1 ].
Key Considerations
- Pulmonary valve atresia with VSD represents the most extreme form of ToF, with significant implications for management and outcomes [ 1 ].
- The management of pulmonary valve atresia involves staged surgical repair, often starting with a systemic-to-pulmonary shunt procedure in the neonatal period, followed by complete repair later [ 1 ].
- Complete repair typically involves closing the VSD and establishing continuity between the right ventricle and pulmonary arteries, which may require a conduit [ 1 ].
- Patients with repaired ToF or pulmonary valve stenosis are at risk for pulmonary valve dysfunction or branch pulmonary artery stenosis, necessitating lifelong cardiology follow-up [ 1 ].
Management and Outcomes
- The definitive treatment of ToF is surgical repair of the right ventricular outflow tract obstruction and VSD [ 1 ].
- Despite advances in surgical techniques, patients with repaired ToF are at risk for complications such as pulmonary regurgitation, ventricular arrhythmias, and right heart failure [ 1 ].
- Timely pulmonary valve replacement and pulmonary artery rehabilitation are crucial for preventing poor outcomes in these patients [ 1 ].
From the Research
Relationship Between Pulmonary Valve Atresia and Tetralogy of Fallot (ToF)
The relationship between pulmonary valve atresia and Tetralogy of Fallot (ToF) is complex and involves various anatomical and physiological considerations. Key aspects of this relationship include:
- Tetralogy of Fallot with pulmonary atresia (ToF-PA) is a heterogeneous group of defects characterized by diverse sources of blood flow to the lungs, often including multiple systemic-to-pulmonary collateral arteries 2, 3.
- The goal of management is to establish pulmonary blood flow from the right ventricle with right ventricular pressures ideally less than half of the systemic pressure, allowing for closure of the ventricular septal defect 3.
- Patients with ToF-PA are at higher risk for reinterventions to address pulmonary arterial or RV-pulmonary artery conduit stenosis, progressive aortic root dilation, and aortic insufficiency, as well as late mortality compared to those with less severe forms of ToF 3, 4.
Surgical Approaches
Surgical approaches for ToF-PA vary and depend on the individual patient's anatomy and physiology:
- An individualized approach based on the morphology of the pulmonary arterial supply can achieve a high rate of complete intracardiac repairs, with pulmonary arterial flow based on the intrapericardial pulmonary arteries in the majority of cases 2.
- Surgical options for first-stage palliation include right ventricle to pulmonary artery connection and modified Blalock-Taussig shunt, with transannular path augmentation potentially offering better rehabilitation of the native pulmonary artery 5.
- The choice of surgical procedure may impact outcomes, including in-hospital mortality, pulmonary artery growth, and the need for reintervention 5.
Outcomes and Prognosis
Outcomes and prognosis for patients with ToF-PA are influenced by various factors, including:
- The presence and severity of pulmonary atresia, as well as the source of pulmonary blood flow 3, 4.
- The type and number of surgical procedures performed, with complete biventricular repair achievable in a significant proportion of patients 2, 4.
- The risk of late complications, such as pulmonary arterial or RV-pulmonary artery conduit stenosis, progressive aortic root dilation, and aortic insufficiency 3, 4.