Children with mild aortic stenosis rarely require treatment.
However, it is important to note that aortic stenosis may be progressive, and that children with mild disease may eventually require treatment later in life.
It is also important to understand that all treatment for aortic valve stenosis is palliative (that is, it does not return the valve to a normal condition). Therefore, before and after successful treatment it is important that all children with aortic stenosis be followed carefully by a qualified cardiologist.
The type of treatment required depends on the type of valve abnormality present. Most commonly, the stenotic aortic valve is of normal size, is bicuspid (that is, two leaflets instead of three), and has a variable degree of fusion along the commissures (or lines of leaflet opening). This "typical" form of aortic valvar stenosis responds very nicely to balloon dilation procedures.
Balloon dilation valvuloplasty is performed at the time of cardiac catheterization and does not require open-heart surgery.
In the newborn, it can be performed through the umbilical artery, thus sparing the use of a small infant's femoral arteries.
More typically in older children the procedure is performed through a femoral artery. Patients are often observed in the hospital overnight, but balloon valvuloplasty can be done as an outpatient procedure in some children.
Surgical valvotomy is an open-heart procedure during which the surgeon opens the valve along the lines of commissural fusion. In many centers this open-heart procedure has been replaced by the less invasive balloon dilation valvuloplasty technique.
Open-heart surgical procedures are required for more complex valves, where simple balloon dilation does not suffice. These valves may be obstructed by severe calcium deposits in their leaflets, or because the valve ring itself is small and underdeveloped. For these conditions surgical aortic valve replacement will be necessary.
The Ross Procedure is an aortic valve replacement option which may be particularly advantageous for young children. In the Ross Procedure, the patient's own pulmonary valve is transplanted to the aortic valve position and the pulmonary valve is replaced with a homograft (human donor valve) from the right ventricle to pulmonary artery.
The early to mid-term experience with the Ross Procedure in children has been outstanding. It is a particularly good option for young children because the replaced aortic valve can continue to grow with the child. It also does not require the use of Coumadin anticoagulation therapy (blood thinner).
A more traditional aortic valve replacement procedure involves the implantation of a mechanical prosthesis in the aortic valve position. Anticoagulation therapy is required with any mechanical valve substitute. When the aortic valve is undersized (also known as a hypoplastic valve annulus or ring), more radical surgical techniques (like the Konno procedure) are required. The Konno procedure is a technique which enlarges the aortic valve ring with an incision into the wall between the two ventricles. The enlarged valve annulus can then accept a more normal size prosthetic aortic valve or pulmonary valve autotransplant.
A child with valvar aortic stenosis and a hypoplastic valve ring might require a Ross-Konno procedure, which is a combination of both the Ross procedure plus a Konno procedure.
Results of Treatment
Results of balloon dilation valvuloplasty have been excellent. This technique was developed in the mid-1980s. Most large centers have a moderate degree of experience with it. The technique decreases the degree of aortic valve obstruction from severe to mild in a large majority of patients.
Children who do not experience excellent relief of obstruction with a technically adequate balloon dilation procedure usually will have more complex disease, such as calcified valve leaflets or a small valve ring.
Balloon dilation valvuloplasty does cause valve insufficiency (or leakage), but this is mild in the majority of patients. In approximately 3 percent to 5 percent of the patients the balloon procedure will create severe aortic valve insufficiency. Severe aortic valve insufficiency may require surgical intervention (although rarely emergently).
Long-term follow-up studies of balloon dilation valvuloplasty show that excellent relief of obstruction persists for several years.
However, like surgical valvotomy in the past, recurrent valve obstruction does occur in many children during the next 5-10 years. Recurrent narrowing is perhaps related to patient growth and chronic valve changes. Many of these children will require repeat balloon dilation or surgical valve replacement procedures.
The outcomes of open-heart surgical procedures for severe aortic valvar stenosis have been excellent. The mortality risk for surgical valve replacement, either prosthetic valve or the Ross Procedure, is less than 3 percent in experienced centers. These procedures effectively relieve all aortic stenosis and insufficiency with low complication rates.
When valve replacements occur in young children, the long-term concern is that the child will outgrow the size of the artificial valve and will require a repeat surgical valve replacement in later years.
When adult-sized artificial aortic valves are implanted in large children and adolescents, they are expected to last 20 years or more with excellent function.
The Ross Procedure raises several unique issues which require evaluation as children grow. The patient's native pulmonary valve is implanted in the aortic valve position, and may dilate. This dilation may eventually lead to some degree of valve insufficiency over time.
In addition, a conduit is placed between the right ventricle and pulmonary artery (to replace the native pulmonary valve). If the Ross Procedure is performed in an infant or small child, this right-sided conduit will need to be replaced later in childhood as the child grows.
It is important to understand that all the treatments for aortic stenosis are palliative, not curative.
An outstanding balloon dilation procedure may leave the patient with only mild aortic stenosis, but not a normal valve.
An outstanding valve replacement operation will relieve essentially all outflow obstruction, but leaves the child with an artificial valve.
Long-term follow-up, with regular evaluations by a qualified cardiologist, is essential to helping provide the highest quality outcome for patients with aortic stenosis.