Virtual Medical Centre

Patent Ductus Arteriosus (PDA)

• What is Patent Ductus Arteriosus?
• Who gets Patent Ductus Arteriosus?
• Predisposing Factors
• Progression
• Probable Outcomes
• How is Patent Ductus Arteriosus Diagnosed?
• How is Patent Ductus Arteriosus treated?
• Patent Ductus Arteriosus References
• Drugs/Products Associated with Patent Ductus Arteriosus

What is Patent Ductus Arteriosus?

Patent ductus arteriosus (PDA) is a condition where a temporary blood vessel near an unborn baby's heart, the ductus arteriosus, fails to close after birth. (The blood vessel normally closes after birth because it is no longer needed). The word "patent" means open.

Who gets Patent Ductus Arteriosus?

About 1 in 2000 live births.

Predisposing Factors

The aetiology (causes or origins) of congenital heart defects are not understood, but several factors are known to be associated:

(1) Maternal drug abuse, alcohol abuse and radiation exposure.
(2) Maternal infection, particularly rubella.
(3) Genetic abnormalities
(4) Chromosomal abnormalities (septal defects are associated with Trisomy 21- Down's syndrome)

Progression

The ductus arteriosus serves to bypass the lungs in fetal circulation and usually closes in response to high oxygen tensions after birth.

In sizeable defects blood is shunted from the aorta to the pulmonary vessels. This is due to the higher pressures in the systemic circulation. This produces a volume load on the left ventricle which leads to heart failure and lung congestion.

In the longer term, increased flow rates through the pulmonary (lung) circulation lead to pulmonary fibrosis (leading to non-functioning lung) and pulmonary hypertension.
In advanced severe disease, the pulmonary artery pressure can exceed the aortic pressure causing reversal of the shunt and cyanosis - a poor prognostic factor.