Anatomy
Most cases of valvular pulmonary stenosis are congenital in origin. Acquired pulmonary stenosis are less common but may be caused by carcinoid syndrome, rheumatic fever, stenosis of bioprosthetic or valved conduits used in repair of complex congenital lesions involving the pulmonary valve , such as tetralogy of Fallot, pulmonary atresia , truncus arteriosus or transposition of great arteries with pulmonary stenosis.
Pulmonary is associated with Noonan’s Syndrome, Trisomy 18, Tetal valproate syndrome, maternal rubella, neurofibromatosis, LEOPARD syndrome, William’s syndrome.
Physiology
The presentation of PS depends on the degree of obstruction and associated anomalies. Mild and moderate PS leads to an ejection systolic murmur and increasing degrees of RV strain. Severe (critical) PS behaves more like pulmonary atresia and is a duct dependent cyanotic heart defect.
Management
In neonates with critical pulmonary stenosis where pulmonary blood flow is duct dependent, initial management is to maintain patency of ductus arteriosus using prostaglandin infusion.
Regular review with echocardiography
Balloon dilatation when gradient reaches 64mmHg across the valve
Surgery is recommended for patients with severe pulmonary stenosis and an associated hypoplastic pulmonary annulus, severe pulmonary regurgitation, subvalvular pulmonic stenosis, or supravalvular pulmonic stenosis. Surgery is also preferred for most dysplastic valves and when there is associated severe tricuspid regurgitation.
Clinical
Asymptomatic (not cyanosed).
(Note: In neonates with critical pulmonary stenosis, there is shunting across the patent foramen ovale, hence neonates may present with cyanosis; there may be no murmur in critical pulmonary stenosis)
Ejection systolic murmur at upper sternal edge from Day 1 ; radiating to the back and both axilla. There may be a thrill at left upper sternal edge.
May be supravalvular, valvular (ejection click) or subvalvular
Quiet P2.
Split S2 (but moves normally with respiration).
Investigations
ECG – Right ventricular hypertrophy, Right axis deviation
CXR – Normal, Prominent pulmonary artery caused by post-stenotic dilatation of main pulmonary artery.
Exam vignette
I examined Cheryl, a 9-year-old girl who looks well-grown for her age and I would like to plot her height and weight on a growth chart.
She is pink and not in respiratory distress.
There are no dysmorphic features or finger clubbing. There are no scars on her chest. She has a grade 3/6 ejection systolic murmur audible all over praecordium but loudest at left upper sternal edge radiating to her back and axilla.
She has right ventricular outflow obstruction such as pulmonary stenosis.
