What happens if PDA is left untreated ?

The changes mentioned before become worse. Heart failure sets in. The child does not grow and develop normally. Due to the turbulent blood flow, there is an increased risk of infection inside the blood vessels - called INFECTIVE ENDOCARDITIS. In late stages, the blood pressure in the lungs becomes very high - severe pulmonary hypertension - and at this time, even with surgery, there will be no improvement. The limit for "operability" has been crossed. The condition is called EISENMENGER syndrome.

PDA as a part of other conditions

Sometimes a Ductus Arteriosus may remain patent (PDA) as a part of other heart diseases. In such a situation, the PDA may indeed be the only route of blood flow into the lungs or the rest of the body ! This is called a DUCT DEPENDENT circulation. The PDA then should REMAIN PATENT, until repair of the associated condition is performed. A medicine called PROSTAGLANDIN is used to keep the ductus open in these patients.

When should a PDA be closed ?

When a PDA is the only heart defect, it needs to be closed. In duct dependent circulation, it is closed at the time of repair of the other heart defects.
In very small children with severe symptoms of heart failure, closure of the PDA is necessary immediately. It may be truly life-saving in these cases. If it does not produce serious problems, closure is not urgent. Still, it is better to close a PDA as early as possible, to avoid the risk of infection and pulmonary hypertension.