Can a patent ductus arteriosus (PDA) in Tetralogy of Fallot (TOF) with pulmonary atresia and Major Aortopulmonary Collateral Arteries (MAPCAs) close spontaneously?

From the Guidelines

In tetralogy of Fallot with pulmonary atresia and major aortopulmonary collateral arteries (MAPCAs), a patent ductus arteriosus (PDA) typically does not close spontaneously, as it serves as a critical source of pulmonary blood flow. Unlike in normal cardiac anatomy where the PDA usually closes within the first few days of life, in this complex congenital heart defect, spontaneous closure would be detrimental as it could severely reduce blood flow to the lungs, causing dangerous hypoxemia 1. The clinical and physiological manifestations of the PDA are dependent on the size of the vessel and the relative systemic and pulmonary vascular resistances, as noted in the 2018 AHA/ACC guideline for the management of adults with congenital heart disease 1.

For this reason, prostaglandin E1 (PGE1) is often administered at 0.01-0.1 mcg/kg/min intravenously to maintain ductal patency until surgical intervention can be performed. The PDA in this condition is considered a vital structure rather than a defect to be closed. Management typically involves surgical placement of systemic-to-pulmonary shunts or complete repair with right ventricle to pulmonary artery conduit placement, depending on the patient's anatomy and clinical status. Key considerations include:

• The size of the PDA and its impact on pulmonary blood flow
• The presence and severity of pulmonary hypertension
• The overall clinical status of the patient, including symptoms and functional capacity The fundamental reason for this difference is that in tetralogy of Fallot with pulmonary atresia, the normal pathway for blood to reach the lungs is completely blocked, making alternative routes like the PDA and MAPCAs essential for survival. As such, maintaining patency of the PDA is crucial until a more definitive surgical repair can be undertaken.

From the Research

Spontaneous Closure of Patent Ductus Arteriosus

• There is no direct evidence in the provided studies to suggest that a patent ductus arteriosus (PDA) in tetralogy of Fallot with pulmonary atresia and major aortopulmonary collateral arteries (MAPCAs) can close spontaneously 2, 3, 4, 5, 6.
• The studies focus on the surgical treatment and management of tetralogy of Fallot with pulmonary atresia, including the use of staged repair, primary repair, and unifocalization procedures 2, 3, 5, 6.
• The presence of a PDA is often associated with ductus-dependent pulmonary circulation, and the management of these patients typically involves surgical intervention to establish pulmonary blood flow 4, 6.
• The studies do not provide information on the natural history of PDA in this specific patient population or the likelihood of spontaneous closure.

Management of Tetralogy of Fallot with Pulmonary Atresia

• The management of tetralogy of Fallot with pulmonary atresia is complex and often requires a individualized approach, taking into account the source of pulmonary blood flow and the presence of MAPCAs 3, 4, 6.
• Surgical procedures, such as unifocalization and right ventricular to pulmonary artery conduit implantation, are often used to establish pulmonary blood flow and promote growth of the pulmonary arteries 3, 5, 6.
• The goal of management is to achieve a biventricular repair with low right ventricular pressures, allowing for closure of the ventricular septal defect and promoting long-term survival 4, 6.