While in the womb, two major arteries that connect to the heart are joined by one blood vessel known as the ductus arteriosus. It is vital for fetal blood circulation, but it should close within days after birth.
When it fails to close, blood from the pulmonary artery mixes with blood from the aorta and flows the wrong way. The defect is known as Patent ductus arteriosus or PDA. Blood pressure in the arteries of the lungs increases and causes pulmonary hypertension. The heart must work harder and can become damaged. The possible causes of PDA are unclear, but it is thought to be caused by environmental influences or a hereditary defect.
Small PDAs can go unnoticed for decades, but large PDAs can become life-threatening very quickly. Doctors often hear a heart murmur during a routine pediatric exam. The symptoms depend on the severity of the defect and may include:
In some cases the PDA will shrivel and close by itself. However, life-threatening complications can occur if the PDA is large and goes uncorrected. The heart can weaken, enlarge and eventually fail. Arrhythmias and infection can also occur. Treatment depends on the severity of the PDA and may include:
Prognosis is good for otherwise healthy kids when a patent ductus arteriosus is treated.