What is Pulmonary Stenosis
Stenosis of the pulmonary valve or infundibulum increases the resistance to outflow, raises the right ventricular pressure, and limits pulmonary blood flow. In the absence of associated shunts, arterial saturation is normal, but severe stenosis causes peripheral cyanosis by reducing cardiac output. Clubbing and polycythemia do not develop unless a patent foramen ovale or atrial septal defect is present, permitting right-to-left shunting.
Clinical Findings of Pulmonary Stenosis
Symptoms and Signs of Pulmonary Stenosis
Mild cases (right ventricular-pulmonary artery gradient < 30 mm Hg) are asymptomatic. Moderate to severe stenosis (gradients 50 to > 80 mm Hg) may cause dyspnea on exertion, syncope, chest pain, and eventually right ventricular failure.
There is a palpable parasternal lift. A loud, harsh systolic murmur and a prominent thrill are present in the left second and third interspaces parasternally; the murmur is in the third and fourth interspaces in infundibular stenosis. The second sound is obscured by the murmur in severe cases; the pulmonary component is diminished, delayed, or absent. Both components are audible in mild cases. A right-sided S4 and a prominent a wave in the venous pulse are present in severe cases.
Prognosis & Treatment of Pulmonary Stenosis
Patients with mild pulmonary stenosis may have a normal life span. Moderate stenosis may be asymptomatic in childhood and adolescence, but symptoms may appear as patients grow older. Severe stenosis is associated with sudden death and can cause heart failure in patients in their 20s and 30s.
Symptomatic patients or those with evidence of right ventricular hypertrophy and resting gradients over 75–80 mm Hg require correction in most cases. Percutaneous balloon valvuloplasty has proved successful and is usually the treatment of choice. Surgery can be performed with an operative mortality rate of 2–4% and an excellent long-term result in most cases.