PULMONARY STENOSIS

CLASSIFICATION

• Valvular type
• Varying degrees of fusion of the valve leaflets which for a diaphragm and small hole for blood to exit the right ventricle.
• Dysplastic pulmonary valve (less commonly) with three thickened (unfused) cusps.
• Infundibulum
• Fibrous ring or thickened muscle tissue.
• Pulmonary valve may be normal.

ASSOCIATED ANOMALIES

• Noonan's syndrome - Valvular type.
• Maternal rubella.
• Total anomalous pulmonary venous drainage, ASD, supravalvular aortic stenosis, and tetralogy of Fallot.

ULTRASOUND

• Dilatation of the proximal pulmonary artery (post stenotic). This may be difficult to appreciate antenatally.
• The degree of dilatation may not be proportional to the severity of the stenosis.
• Not found in infundibular stenosis.
• Right Ventricular hypertrophy (small RV chamber).
• Right atrium may be dilated and have thickened walls. There may be an associated atrial septal defect.
• Turbulent flow and increased velocities distal to the valve on color doppler.
• Congestive heart failure and hydrops may occur in severe stenosis.
• Tricuspid and mitral incompetence may be present.

Pulmonary valvular stenosis: Post stenotic dilatation. Velocity proximal to valve = 100 cm/sec. Velocity distal to valve = 200 cm/sec

REFERENCES

1. Todros T, Presbitero P, Gagliotti J et.al. Pulmonary stenosis with intact ventricular septum: documentation of the development of the lesion echocardiographically during fetal life. Int J Cardiol 1988;19:355-360.