Unilateral pulmonary artery atresia

Unilateral pulmonary artery atresia (UPAA), also known as unilateral absence of the pulmonary artery (UAPA) or proximal interruption of the pulmonary artery, is a variant of pulmonary artery atresia

The term interruption is preferred by some to absence or atresia because the anomaly pertains only to the proximal pulmonary artery while the distal pulmonary arterial tree is maintained 13.

The estimated prevalence is around 1 in 200,000 young adults. The reported frequency on the right side is slightly greater for some reason 10.

Can be variable and include:

It commonly occurs on the side opposite to that of the aortic arch.

The distal branches of the affected artery usually remain intact and can be supplied by collateral vessels from other arteries such as bronchial, intercostal, internal thoracic, subdiaphragmatic, subclavian, or even coronary arteries.

It occurs in association with other cardiac anomalies in ~60% of cases:

In around 40% of cases they occur in isolation, where it is then termed as:

Features can vary depending on which side is affected.

May be seen as volume loss to the ipsilateral lung with overinflation (+/- herniation across the midline) of the contralateral lung 4. The affected lung usually appears hyperlucent due to oligemia, whereas the contralateral lung is supplied by a prominent pulmonary artery.

Allows direct visualization of the absence of the affected pulmonary artery. Volume loss to the affected lung is also shown. Extensive collaterals can be visualized. May allow recognition of associated cardiac anomalies.

Recognized complications include:

Treatment is often around the management of complications in asymptomatic individuals. There is often no commonly accepted consensus on a particular treatment strategy.

It is thought to have been first described by O Frantzel in 1868 3

Plain film differential for small lung includes:

Congenital heart disease

There is more than one way to present the variety of congenital heart diseases. Whichever way they are categorized, it is helpful to have a working understanding of normal and fetal circulation, as well as an understanding of the segmental approach to imaging in congenital heart disease.

Article information

rID: 31904
System: Vascular, Chest
Synonyms or Alternate Spellings:
  • proximal interruption of pulmonary artery
  • proximal interruption of the pulmonary artery
  • Unilateral absence of pulmonary artery (UAPA)
  • Unilateral absence of the pulmonary artery
  • Unilateral absence pulmonary artery (UAPA)
  • Unilateral absence of the pulmonary artery (UAPA)
  • Unilateral pulmonary artery atresia (UPAA)
  • UPAA
  • UAPA

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Cases and figures

  • Case 1: left PA atresia
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  • Case 2: right-sided
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  • Case 3: Absent right PA
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