Pulmonary Valve Stenosis (Valvular PS)
Pulmonary stenosis is the second most common congenital heart defect. It accounts for about 10 % of all congenital heart diseases. Half of all congenital heart defects include PS as a component of the defect.
An obstruction to blood flow from the right ventricle to the pulmonary arteries is called pulmonary stenosis. The blockage is usually at the level of the pulmonary valve and is called valvular PS; however, in rare cases, the blockage may be above the valve (supravalvular PS), below the valve (subvalvular PS), or a combination of blockages (stenosis), as may be seen in patients with Tetralogy of Fallot.
The pulmonary valve opens to let blood flow from the right ventricle to the lungs. Narrowing at the level of the pulmonary valve (valvular PS) may be due to a thickened pulmonary valve. The pulmonary valve leaflets (cusps) may be partially fused as well. This will prevent the pulmonary valve to open all the way. In addition, the pulmonary valve annulus, where the pulmonary valve sits, may be small as well. Pulmonary stenosis causes the right ventricle to pump harder to get the blood past the blockage. As time goes by, the muscle of the right ventricle will become thicker (right ventricular hypertrophy).
Pulmonary stenosis usually occurs during pregnancy while the baby’s heart is developing. In most cases, the cause is unknown. Pulmonary valve stenosis may be familial or associated with chromosomal abnormalities, Noonan syndrome, Alagille, Cornelia de Lange, cardiofaciocutaneous syndrome, Costello, and Tetralogy of Fallot.
Patients with mild-moderate PS are usually asymptomatic. Most patients will have a clicking sound and a heart murmur that is picked up during cardiac auscultation. The second heart sound is widely split. If the pulmonary stenosis is severe, especially in babies, some cyanosis (blueness) may occur, especially while the child is crying. The cyanosis may be visible in the nail beds, lips, or oral mucosa. Rarely, patients with severe PS may experience rapid breathing, fatigue, or dizziness.
Cardiovascular Tests and Diagnosis:
In patients with mild to moderate PS there may be a soft murmur with a click and no symptoms at all. In more severe cases, the murmur will become louder and longer. It may transmit throughout the chest, both axillae, and to the back. The electrocardiogram may show some abnormalities. The chest x-ray usually shows a normal heart size. In severe pulmonary stenosis there may be an increase in heart size and dilatation of the pulmonary artery.
The echocardiogram helps to establish the diagnosis. The echocardiogram may show a thickened valve that does not open all the way. It may also show dilatation of the main pulmonary artery and right ventricular hypertrophy. The echocardiogram helps to evaluate the size of the pulmonary valve annulus. The Doppler echocardiogram will help determine the severity of the pulmonary stenosis.
Mild valvular PS does not require therapeutic intervention. Optimal dental hygiene and routine dental appointments are emphasized. SBE prophylaxis is not necessary. Patients with severe valvular PS may undergo balloon valvuloplasty in order to dilate the stenotic pulmonary valve. This procedure is performed during an interventional cardiac catheterization.
Newborns with critical pulmonary stenosis with cyanosis may benefit from a medication called prostaglandin, at least temporarily until the patient undergoes valvuloplasty.
The outcome is good. Patients with mild pulmonary stenosis do quite well as less than 5% will have progressive obstruction. On the other hand, if the obstruction is moderate-severe, then most of the time they will require interventional cardiac catheterization. Pulmonary valvuloplasty is quite effective but will leave some degree of leakage (pulmonary regurgitation) in the pulmonary valve. These patients, however, usually do not require any further intervention. The life expectancy in patients with PS is normal. They will not have any restrictions.
Most patients will be followed by Dr. Villafañe every one to two years.
In cases of critical pulmonary stenosis in newborns, the prognosis may depend on the size of the right ventricle and its function. As time passes, the size of the right ventricle may improve.
Virtually all patients with PS will be able to participate in competitive sports.