Pulmonary valve – stenosis

Pulmonary valve – stenosis

Description

Pulmonary stenosis can be isolated, which is a common condition but often too minor to be detected in utero, or it can be part of a complex of heart malformation which is more common in fetal practice. The pulmonary valve is abnormally formed and causes a variable degree of obstruction to right heart output. With an isolated lesion the affected child will usually present with an asymptomatic cardiac murmur. If the stenosis is mild, it may require no treatment; if moderate or severe it is usually successfully treated by balloon catheter dilatation. If it progresses to pulmonary atresia in utero, which can occur, it is associated with a poor prognosis, which will be detailed in the section on pulmonary atresia. If pulmonary stenosis is part of a more complex form of heart malformation, presentation will be dictated by the dominant lesion but will often be due to cyanosis.

Diagnosis

In isolated forms of pulmonary stenosis, the four chamber view will usually be normal but if the pulmonary stenosis is severe, there may be right ventricular hypertrophy and depressed function. The right heart may be dilated or small. The pulmonary valve may appear thickened and restrictive in motion. Normally the valve leaflets ‘disappear’ during systole as they flatten back against the walls of the pulmonary artery. In pulmonary stenosis, the valve cusps are seen throughout the cardiac cycle. Colour Doppler flow will show turbulence at the pulmonary valve with an increased velocity of flow in the pulmonary artery using pulsed Doppler. The pulmonary artery will commonly be smaller than normal for the gestation and may be smaller than the aorta.

Differential Diagnosis

Right ventricular hypertrophy and dysfunction may have many causes, including placental dysfunction, ductal constriction, and coarctation of the aorta. There is no alternative explanation for a thickened restricted pulmonary valve with accelerated turbulent flow across the valve.

Sonographic Features

Thickened restricted pulmonary valve leaflets Turbulent flow across the pulmonary valve Pulmonary artery Doppler flow velocity increased above normal for gestational age Pulmonary artery small for gestational age Right ventricular hypertrophy may be evident If severe, the right ventricle can be dilated and the contraction can be decreased

Associated Syndromes

  • 9p-
  • Hydantoin
  • Kartagenes
  • Multiple Lentigines (Leopard)
  • Noonans
  • Pallister-Hall
  • Rubella
  • Trisomy 18

References

Anderson RH, McCartney FJ, Shinebourne EA, Tynan M (Eds) In: Paediatric Cardiology Churchill Livingstone: Edinburgh, p959-977
Allan LD, Sharland GK, Milburn A, Lockhart SM, Groves AMM, Anderson RH, Cook AC, Fagg NLK Prospective diagnosis of 1,006 consecutive cases of congenital heart disease in the fetus J Am Coll Cardiol 23:1452-8
Allan LD, Sharland G, Cook A In: Colour Atlas of Fetal Cardiology Mosby-Wolfe: London, p93-101
Rocchini AP, Emmanouilides GC In: Heart Disease in Infants, Children and Adolescents Adams FH, Emmanouilides GC, Riemenschneider TA (Eds) Williams and Wilkins: Baltimore, p308-338
Hornberger LK, Benacerraf BR, Bromley BS, Spevak PJ, Sanders SP Prenatal detection of severe right ventricular outflow tract obstruction: pulmonary stenosis and pulmonary atresia J Ultrasound Med 13:743-50