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Patent Ductus Arteriosus
 PDA


General Considerations

  • Persistent communication between the thoracic aorta and the pulmonary artery by the ductus arteriosus
  • In fetal life, ductus carried blood from the pulmonary artery to the aorta, essentially bypassing the fetal lungs
  • The ductus usually closes functionally within a few hours after birth
    • If the ductus remains patent beyond 3 months, it is considered abnormal
  • The effect of the left-to-right shunt will depend on the size of the shunt and the pulmonary vascular resistance
  • If ductus persists, the shunt will be left-to-right from the aorta to the pulmonary artery
  • May be an obligatory shunt in complex cardiac lesions
    • Hypoplastic left heart syndrome
    • D-Transposition
    • Pulmonary atresia

Clinical Findings

  • Although presentation can be at any age, PDA usually presents in childhood
  • If shunt is large, may present with congestive heart failure
  • Acyanotic, until or unless Eisenmenger’s physiology leads to reversal of the flow to right-to-left
  • Increased pulmonary infections
  • Inability or difficulty with feeding
  • Weight loss (or no weight gain)

Imaging Findings

  • The diagnosis is based on clinical findings, including EKG, imaging and echocardiographic findings, the latter being the primary means of imaging the lesion
  • Chest radiographs yield non-specific findings such as CHF, a large main pulmonary artery and increased shunt vasculature
  • The ductus may be long or short, relatively straight or tortuous
  • Tends to be wider on the aortic side
  • Forms acute angle with aorta in isolated PDA; more obtuse angle with associated congenital heart disease
  • When closed, the ductus forms the ligamentum arteriosus, which may calcify in aorto-pulmonary window
  • MRI findings
    • Usually cardiac-gated T1 weighted (black blood) imaging
    • Sagittal oblique plane through aortic arch shows ductus

Complications

  • Aortic rupture
  • Eisenmenger physiology
  • Left heart failure
  • Myocardial ischemia
  • Necrotizing enterocolitis
  • Pulmonary hypertension

Treatment

  • If administered within two weeks of birth, intravenous indomethacin or IV ibuprofen are often effective in closing a PDA
  • Catheter closure
  • Surgical ligation
  • It may be desirable to keep the ductus patent (as in cyanotic heart disease) in which case Prostaglandin E1 can be used

Prognosis

  • Generally considered excellent in patients in whom the PDA is an isolated abnormality

Patent Ductus Arteriosus (PDA). Upper: Sagittal reconstruction of contrast-enhanced cardiac CT shows a tubular communication (yellow arrow) between the Aorta (Ao) and the pulmonary artery (PA). A wisp of more slightly enhancing contrast is seen coming from the PDA into the PA (white arrow). Lower: Axial views again show the tubular PDA (yellow arrows) emanating from the aorta (AO).
For these same photos without the arrows, click here and here
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