Pulmonary stenosis – Cardiology Basics

Pulmonary stenosis – Cardiology Basics

Pulmonary stenosis is most often congenital, though occasionally it can occur in carcinoid syndrome and related disorders. Dysplastic pulmonary valve occurs in Noonan’s syndrome. Pulmonary stenosis increases the workload of the right ventricle, which gets hypertrophied in an attempt to overcome the obstruction. Hypertrophied right ventricle becomes less compliant, increasing its filling pressure.

Decrease in right ventricular compliance increases right atrial pressure. This will be more when the right ventricle fails ultimately. Forceful right atrial contraction produces a prominent a wave in the jugular venous pulse.  Right atrium enlarges due to the overload.

Increase in right atrial pressure is transmitted to the superior and inferior vena cava as well. Congestion of inferior vena cava can cause hepatomegaly in late stages and there can be a presystolic pulsation corresponding to the prominent a wave in jugular venous pulse. Pedal edema occurs when right heart failure sets in.

Ascites can occur in advanced cases. Jugular venous pressure gets elevated when right heart failure occurs. Hepatic and renal dysfunction can occur in late stages of heart failure.

Clinically important findings in valvar pulmonary stenosis are the ejection systolic murmur and phasic ejection click. Ejection systolic murmur in the pulmonary area may be associated with a thrill. Phasic ejection click is better heard in expiration and is the only right sided event which is better heard in expiration. Ejection click may be also called ejection sound. It moves closer to the first heart sound in inspiration.

Pulmonary stenosis can be documented by an echocardiogram. Doppler echocardiography measures the transvalvar gradient and helps in assessing severity of pulmonary stenosis. Right ventricular hypertrophy and right atrial enlargement as well as plethora of the inferior vena cava may be seen in severe cases. X-ray chest may show post stenotic dilatation of main pulmonary artery and left pulmonary artery. ECG may show right axis deviation, ventricular hypertrophy and right atrial overload.

In severe cases, an obstructed pulmonary valve can be opened up by balloon pulmonary valvotomy. In this procedure, a balloon catheter is introduced through femoral vein and guided to the right heart under fluoroscopy. When balloon is across the pulmonary valve, it is inflated, relieving the obstruction. The procedure is done under local anaesthesia and there is no need for a sternotomy.

In the past, surgical pulmonary valvotomy was done by midline sternotomy. It is seldom done now a days, unless there are other associated defects which need repair by open heart surgery under cardiopulmonary bypass.