Is spontaneous closure of a patent arterial duct common?

Early spontaneous closure of large arterial ducts in two term neonates with Ebstein anomaly after failed attempts of transcatheter closure

In neonatal Ebstein's anomaly of the tricuspid valve, prolonged ductal patency in patients without anatomic pulmonary valve atresia can be deleterious. Circular shunts may develop in patients with different degrees of pulmonary and tricuspid insufficiency. Closure of the arterial duct may result in haemodynamic improvement in particular scenarios. The transcatheter approach is a valuable closure alternative despite some technical difficulties in large-sized arterial ducts and low birth weight neonates. Herein, we report on two consecutive term newborns with Ebstein's anomaly and large arterial ducts in whom mechanical stimulus of the arterial duct during failed attempts of transcatheter closure led after two days to definitive closure followed by good clinical outcomes.

Interaction between pulmonary vasculature and the patent ductus arteriosus in very premature infants

BACKGROUND

The benefits of closing the ductus arteriosus in very preterm infants have not been convincingly shown in numerous clinical trials. Because a large untreated ductus arteriosus can cause death from congestive heart failure in infants born at term, we need to explain why this might not occur in premature infants born at <28 weeks' gestation.

METHODS

Based on information in the literature, I have commented on the possible relationship between the pulmonary vasculature and the shunt through the patent ductus arteriosus.

RESULTS

Many of these infants have bronchopulmonary dysplasia, in which animal and human studies have shown a reduced number of capillaries and small pulmonary arteries as well as reduction in vascular endothelial growth factor (VEGF) and platelet endothelial cell adhesion molecule-1 (PECAM-1). Both of these import angiogenic factors. Some who do not have bronchopulmonary dysplasia may have a restricted pulmonary vascular bed.

CONCLUSIONS

The increased pulmonary vascular resistance in very premature infants may restrict pulmonary blood flow even if the ductus is large, thus reducing the urgency for ductus closure.