Pulmonary Stenosis (PS)

Anatomy & Physiology

The pulmonary valve commissures are usually partially fused together preventing the valve from opening properly. In some instances the leaflets are dysplastic (Noonan's syndrome). Beyond the stenotic valve the main pulmonary artery is usually dilated. The degree of right ventricular hypertrophy depends upon the degree of stenosis. When severe the RV may be suprasystemic and if, as is usual, tricuspid regurgitation is present then right to left shunting may occur at atrial level leading to cyanosis.

Presentation

This accounts for 8% of heart disease. If severe it presents in the early neonatal period with a cyanotic and often collapsed baby. Less severe disease presents as an asymptomatic ejection systolic murmur heard at the left upper sternal edge. In many patients the murmur is preceded by a click. The second sound is usually widely split due to the delay in RV emptying

Investigations

Electrocardiogram

The ECG often shows signs of right ventricular hypertrophy with right axis deviation, tall R waves over the right sided V leads and altered T wave morphology.

Chest X-ray

The CXR usually shows a normal sized heart, the main pulmonary artery is large due to post stenotic dilation and there may be reduced vascular markings.

Echocardiogram

Echocardiography confirms the diagnosis and the Doppler velocity or tricuspid regurgitant jet allows an estimation of the severity.

Natural History

25% of those without critical stenosis presenting within the neonatal period will have a progressive lesion requiring intervention at some stage. Mild stenosis can occasionally regress. Moderate stenosis (< 50 mmHg) usually remains stable but RV failure can occur in later life. Rowland et al (Am J Cardiol 1997 Feb 1;79(3):344-9)

Management

Initially surgery was successfully used to undertake a valvotomy either as a closed procedure using dilators passed through the right ventricular outflow tract or on bypass with direct vision.

Subsequently in 1982 Dr Jean Khan undertook a transcatheter balloon approach and this is now the treatment of choice. This is usually undertaken when the transvalvar gradient is 36mmHg or more (3 m/s Doppler velocity). If the stenosis is very severe then the RV may be at systemic pressure or even higher.

The procedure entails putting a catheter in the right femoral vein and passing it through the right atrium and right ventricle and crossing the pulmonary valve. A wire is then passed through the catheter in the distil pulmonary artery to stabilise it. The catheter is then withdrawn leaving the wire in place. A balloon catheter is then "railroaded" over the wire to the valve and inflated for a few seconds. It is then deflated and removed. The procedure is relatively straightforward and the risk of complication is small.

Pulmonary Valvotomy Animation (file download time 15s)

Hover the mouse over the heart to see the animation

Prognosis

The long term results of pulmonary balloon valvuloplasty are excellent. The restenosis rate is less than 5% (Jarrar et al Am Heart J 1999;138:950-4). All however have pulmonary regurgitation to a greater or lesser extent. Similar results are obtained even if the procedure is carried out in late childhood or as an adult. (Chen et al. New Eng J Med 1996;335:21)

This page was last edited 18/3/2004

Acknowledgements