Absent pulmonary valve syndrome

Newborn with

abnormal prenatal cardiac ultrasound. CXR AP (above) shows an abnormal and prominent contour to the left superior mediastinum. The right superior mediastinum contour represents the thymus. Coronal CT with contrast of the chest (below) shows aneurysmal dilation of the main pulmonary artery. The pulmonary valve was absent.The diagnosis was main pulmonary arterial aneurysm due to absent pulmonary valve syndrome.

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Absent pulmonary valve syndrome (APVS) also known as congenital absence of pulmonary valve or pulmonary valve agenesis is a rare cardiac outflow tract anomaly.

Pathology

It is characterized by completely absent or rudimentary pulmonary valve. It can be associated with aneurysmal dilatation of the pulmonary arteries and compression of the tracheobronchial tree and in turn lead to significant respiratory compromise.

Subtypes

Two types have been descrbied

Fallot type - associated with tetralogy of fallot
non Fallot type

Associations

tetralogy of Fallot
other congenital cardiac syndromes including
- interrupted aortic arch - type B
- transposition of the great arteries
- pulmonary branching abnormalities
- atrioventricular septal defect (ASD)
- persistent ductus arteriosus
- agenesis of ductus arteriosus
syndromes
- DiGeorge syndrome

Radiographic features

Antenatal ultrasound

Can show aneurysmal dilatation of pulmonary artery with some authors suggest a bow tie or balloon like configuration of pulmonary arteries as an indicative feature . May also show massive regurgitation of the pulmonary valve +/- presence of a VSD and/or an overriding aorta.