Absent pulmonary valve syndrome

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.

CT / MRI 

May allow direct visualization of rudimentary or absent pulmonary valve, dilated main pulmonary artery with or without dilatation of its branches.

Treatment and prognosis

The prognosis is generally considered poor. Several surgical method have been adopted which include

• replacement with a valved conduit
• replacement with a monocusp valve
• valveless repair
• pulmonary artery reduction
• Lecompte maneuver

History and etymology

It is thought to have been first described by Cheevers in 1847 .