From the Guidelines
No, the pulmonary arteries are typically not hypoplastic in patent ductus arteriosus (PDA). In fact, in isolated PDA, the pulmonary arteries are usually normal in size or may even become enlarged due to increased pulmonary blood flow, as noted in the 2010 European Heart Journal guidelines for the management of grown-up congenital heart disease 1. PDA is a condition where the ductus arteriosus, a fetal blood vessel that connects the proximal left pulmonary artery (LPA) and the descending aorta, fails to close after birth. This results in abnormal blood flow from the aorta to the pulmonary artery, causing increased pulmonary blood flow and potential volume overload to the left side of the heart.
Some key points to consider in PDA include:
- The condition can be associated with a variety of congenital heart disease (CHD) lesions, but in adults, it is usually an isolated finding 1.
- PDA originally results in a left-to-right shunt and left ventricular (LV) volume overload, and in moderate and large PDA, pulmonary pressure is elevated 1.
- Pulmonary artery hypoplasia is more commonly associated with other congenital heart defects, such as tetralogy of Fallot, pulmonary atresia, or severe pulmonary stenosis, where there is reduced blood flow to the lungs during development.
In contrast, PDA typically increases pulmonary blood flow, which would not lead to underdevelopment of the pulmonary arteries. Therefore, based on the most recent and highest quality evidence available, pulmonary artery hypoplasia is not a characteristic feature of patent ductus arteriosus.
From the Research
Pulmonary Arteries in Patent Ductus Arteriosus
- The studies provided do not directly state that the pulmonary arteries are hypoplastic in patent ductus arteriosus 2, 3, 4, 5, 6.
Growth of Pulmonary Arteries
- PDA stenting can promote the growth of pulmonary arteries in patients with duct-dependent pulmonary circulation 3.
- The growth of pulmonary arteries can be evaluated using various parameters such as pre-branching right and left pulmonary artery diameters, their Z scores, LPA/RPA ratio, McGoon's ratio, and Nakata index 3.
- PDA stenting has been shown to increase the diameters and Z scores of the right and left pulmonary arteries, as well as McGoon's ratio and Nakata index 3.
Comparison of PDA Stent and Modified Blalock-Taussig Shunt
- A comparison of PDA stent and modified Blalock-Taussig shunt as palliation for infants with ductal-dependent pulmonary blood flow found that PDA stent had a lower risk of diuretic use at discharge, procedural complications, and larger and more symmetrical pulmonary arteries at the time of subsequent surgical repair or last follow-up 4.
Effect of PDA on Pulmonary Vascular Disease
- The hemodynamic effects of a PDA can lead to systemic hypoperfusion and volume overload on the left ventricle, and may also have long-standing effects on the pulmonary vasculature 5.
Role of PDA in Bronchopulmonary Dysplasia
- A persistent left-to-right shunt through a PDA can increase the rate of hydrostatic fluid filtration into the lung's interstitium, impair pulmonary mechanics, and prolong the need for mechanical ventilation, which may contribute to the development of bronchopulmonary dysplasia 6.