In severe valvular aortic stenosis, neonates may be fatal in the first week after birth when which event occurs?

In severe valvular aortic stenosis, neonates may be fatal in the first week after birth when which event occurs?

• A. Foramen ovale closes
• B. Umbilical detaches
• C. Pulmonary vascular resistance falls
• D. Ductus closes

Answer: (D)

In severe aortic valve stenosis in a newborn, the baby can become critically dependent on the ductus arteriosus to supply the body with blood. After birth, the ductus arteriosus normally keeps the systemic circulation flowing by shunting blood from the pulmonary artery to the aorta. If this ductus closes, there is no alternative route to deliver blood to the systemic circulation, and the infant can rapidly deteriorate and may die within the first week. The fall of pulmonary vascular resistance after birth and the closure of other fetal shunts do not have the same immediate, life-threatening impact in this scenario as the loss of the ductus arteriosus.

In severe aortic valve stenosis in a newborn, the baby can become critically dependent on the ductus arteriosus to supply the body with blood. After birth, the ductus arteriosus normally keeps the systemic circulation flowing by shunting blood from the pulmonary artery to the aorta. If this ductus closes, there is no alternative route to deliver blood to the systemic circulation, and the infant can rapidly deteriorate and may die within the first week. The fall of pulmonary vascular resistance after birth and the closure of other fetal shunts do not have the same immediate, life-threatening impact in this scenario as the loss of the ductus arteriosus.