Patent ductus arteriosus (PDA) is a condition found in infants that occurs when the ductus arteriosus does not close after birth. 

The ductus arteriousus is an artery that is present in the fetus to connect the pulmonary artery to the aorta. This vessel is necessary to divert blood flow away from the lungs because the lungs are collapsed prior to birth. When the infant is born and begins to breathe, there is a stimulus which causes the ductus arteriousus to close. If the ductus arterious remains open (patent), blood will flow from the aorta to the pulmonary artery and out to the lungs, causing an excess of pulmonary blood flow.

What are the warning signs and symptoms of patent ductus arteriosus?
If a PDA is small, there are generally no symptoms. If the PDA is large, however, there will be a significant excess in blood flow to the lungs, causing the heart to have to pump more blood. This can lead to signs of congestive heart failure, including labored breathing, difficulty feeding, and poor growth.

How is patent ductus arteriosus detected?
The first sign is often the presence of a heart murmur. The diagnosis is documented with an echocardiogram.

What are the treatment options for patent ductus arteriosus?
For many years, the only treatment option for patent ductus arteriosus was surgical closure. More recently, it has been possible to close certain types of PDA during a cardiac catheterization. The catheter is threaded through the ductus. Either a metallic coil or an expandable metallic device is then passed through the catheter and out the end of the catheter until it is positioned within the ductus. This will then obstruct flow through the ductus and the ductus will no longer be patent. Some ductuses, however, are of a certain size and shape that surgery is still necessary.