Patent Ductus Arteriosus (PDA)

Michael P. D'Alessandro, M.D.
Peer Review Status: Internally Peer Reviewed

• Classic form without severe pulmonary hypertension, seen in older children with a continuous murmur
• Infant with a large shunt and congestive heart failure
• PDA with severe pulmonary vascular changes causing reversal of the left to right shunt to a right to left shunt
• PDA complicating respiratory distress in premature infants
• PDA coexisting with other cardiac malformations

Etiology/Pathophysiology:
Ductus ateriosus extends from the main pulmonary artery to the descending aorta, in fetal life it shunts blood from the pulmonary venous circulation to the systemic circulation. At birth increased systemic arterial oxygen concentration leads to closure by 1 week of age. A PDA can be life sustaining in cases with obstructed left venticle outflow or decreased pulmonary blood flow. It causes a left to right shunt due to the systemic arterial pressure being greater than the pulmonary arterial pressure.

Pathology:
Not applicable

Imaging Findings:
Larger PDAs cause shunt vascularity and dilation of left atrium, left ventricle, and aorta. The prominent aortic arch in PDA helps to distinguish it from ASD and VSD which have less prominent or normal aortic arches.

DDX:

• PDA
• ASD - less prominent aortic arches
• VSD - less prominent aortic arches
• ECD

References:
See References Chapter.

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