||Pulmonary Stenosis and the Adult Patient
Though some cases involve severe symptoms shortly after birth, this defect is usually diagnosed during the investigation of children with heart murmurs and no other symptoms and is sometimes not recognized until adulthood. The degree of obstruction may remain stable or increase, depending on how the pulmonary valve changes in response to the patient's growth. In adulthood, there may be an increase in obstruction as calcification of the valve sets in and arrhythmias may develop.
Besides the evaluation of the patient's heart murmur, diagnosis is based on electrocardiography (producing an ECG, or electrocardiogram), chest x-ray, MRI (Magnetic Resonance Imaging), and/or echocardiography (producing an echocardiogram). The ECG is used to determine the severity of the stenosis and will appear normal if the obstruction is mild. Enlargement of the pulmonary artery is often seen with the chest x-ray, though the degree of enlargement does not correspond to the degree of stenosis. The overall anatomy of the heart and the defect itself may be seen on the MRI and echocardiogram. The echocardiogram also permits a rough estimate of the degree of obstruction. A cardiac catheterization procedure may be performed to accurately determine the degree of obstruction, measured by the difference in blood pressure between the right ventricle and pulmonary artery.
Medical management is important to monitor the degree of obstruction and to guard against the development of congestive heart failure. In more severe cases, the patient will experience fatigue, breathlessness (dyspnea), and (rarely) chest pain in response to exertion. Mild cyanosis may also be observed. However, most people with pulmonary stenosis have no external symptoms.
Significant stenosis usually causes hypertrophy (thickening) of the wall of the right ventricle. This may lead to a further narrowing of the right ventricular outflow tract, which can cause failure of the right ventricle and a decreased tolerance for exertion. In some cases, especially for those over 40, there is the risk of sudden death in the absence of treatment.
Moderate obstruction is usually controlled with medications; surgery is recommended if it becomes severe. This operation involves very low risk and an excellent prognosis for a long and active life after surgery. Children and young adults may be treated by balloon valvuloplasty during a cardiac catheterization procedure, which widens the right ventricle outflow tract. The replacement of the pulmonary valve may be necessary in older patients whose valves have become substantially calcified.
Medical follow-up is usually considered to be unnecessary for mild cases of pulmonary stenosis. Lifelong antibiotic therapy is prescribed for patients with moderate or severe obstruction to guard against infection of the heart's internal lining (bacterial endocarditis), though this is not always done for less serious cases.