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ABSENT PULMONARY
VALVE |
The antenatal diagnosis of absent pulmonary valve is a difficult one, resulting in the lesion being rarely diagnosed in utero.
The absent pulmonary valve is usually associated with a VSD, obstruction of the
pulmonary annulus and massively dilated pulmonary arteries. The absence of an
overriding aorta and large rather than small pulmonary artery distinguishes it
from tetralogy of Fallot.
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ULTRASOUND |
- Dilated right ventricle (may be a late finding).
- Dilated pulmonary trunk (the main branches may be normal). Dilatation is usually massive.
- Pulmonary valve leaflets are very rudimentary and dysplastic (resulting in pulmonary incompetence).
- VSD or intact ventricular septum has been reported. (when ventricular septum is intact and the ductus arteriosus is patent, aneurysmal dilatation of the pulmonary artery does not occur) (1).
- Fetal signs of cardiac failure.
- Polyhydramnios due to mechanical obstruction of the esophagus by the enlarged pulmonary artery.
- The large pulmonary arteries may result in extrinsic compression of the airways and postnatal respiratory distress.
- May be associated with tetralogy of Fallot (absent pulmonary valve, overriding aorta, dilated pulmonary arteries and a dilated right ventricle may be present).
- Ductus of ductus arteriosus is not a constant feature. It has been suggested that the ductus arteriosus plays an important role in the development of absent pulmonary valve syndrome. In most cases the ductus is not patent (this is thought to result from failure of an immature sixth artery arch to develop later in pregnancy rather than from complete failure to develop). The presence of a patent ductus in some cases suggests that patency of the ductus is not the primary etiologic feature in the pathogenesis of this syndrome.
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* = Aorta partially overriding ventricular
septum. ** = Absent / rudimentary
pulmonary valve. VSD = Ventricular septal defect. DA = Ductus arteriosus. PA = Main pulmonary artery. LPA = Left pulmonary artery. LA = Left atrium. RV = Right ventricle. RA = Right atrium. |
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Video clip of
Absent Pulmonary Valve
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OUTCOME
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- Survival may occur, however those with the severe form usually die in infancy from cardiac failure.
- Outcome is determined by cardiopulmonary complications related to tracheobronchial compression by the dilated pulmonary arteries.
ASSOCIATED ANOMALIES
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- Aberrations of chromosome 6 and chromosome 22 have been reported from postnatally detected cases.
- Has been reported in association with congenital diaphragmatic hernia and other extracardiac anomalies.
REFERENCES
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- Chenoweth-Mitchell C, Cohen GR, Sims M et.al. Antenatal diagnosis of absent pulmonary valve syndrome. JDMS 1995;11:193-195.
- Callan
NA,