Bicuspid aortic valve occurs when the aortic valve does not develop normally while the baby is in the womb. It is one of the most common congenital heart defect affecting about 20 per 1000 babies born.
The aortic valve (1) is one of four valves in the normal heart. It sits between the left ventricle (2) and the aorta (3). Heart valves are thin flaps of tissue anchored in a fibrous ring. The normal aortic valve has 3 leaflets (4) that open to allow blood to move forward and close to prevent backward blood flow. In bicuspid aortic valve (5), there are only 2 leaflets instead of three and the valve leaflets are often thickened. This can result in obstruction of blood flow across the valve, a condition called aortic stenosis and/or valve leakage, a condition called aortic valve regurgitation. The natural course of bicuspid aortic valve varies widely. There can be severe aortic stenosis at birth, due to incomplete opening of the valve leaflets. Aortic stenosis can also develop during childhood, during adulthood, peaking around the fourth decade of life, or it may never develop. Aortic valve leakage (called aortic regurgitation or aortic insufficiency) is less common during early childhood but can also develop over time. The remainder of this section refers to patients with bicuspid aortic valve without aortic stenosis.
Bicuspid aortic valve alone does not cause symptoms unless significant obstruction or leakage develop. Since the narrowing tends to increase over time and can progress during childhood, follow-up by a specialist is needed.
Children with bicuspid valve are at increased risk for subacute bacterial endocarditis (SBE). This is an infection of the heart caused by bacteria in the blood stream. Children with heart defects are more prone to this problem because of the altered flow of blood through the heart. It can occur after dental work or medical procedures on the GI or respiratory tract because these procedures almost always result in some bacteria entering the blood. SBE can usually be prevented by taking an antibiotic before these procedures.
Symptoms: Bicuspid aortic valve without aortic stenosis does not cause any symptoms.
Physical findings: The presence of an extra heart sound called a "click" and a heart murmur alert the doctor to the possible diagnosis. Since the findings can be quite subtle, the diagnosis may not be made until later childhood or even adulthood.
Medical tests: The suspected diagnosis is confirmed by an echocardiogram. Other tests include an electrocardiogram and chest x-ray.
Treatment is needed only if the valve becomes obstructed or leaky. See section on treatment of aortic stenosis for more information.
SBE prophylaxis: SBE prophylaxis is needed as outlined above.
Exercise guidelines: An individual exercise program is best planned with the doctor so that all factors can be included. Generally, there are no restrictions needed for children with bicuspid aortic valve as long as there is there is no or only slight valve obstruction or leakage.
Beppu S, Suzuki S, Matsuda H et al. Rapidity of progression of aortic stenosis in patients with congenital bicuspid aortic valves. Amer J Cardiol 1993;71:322-327.
Written by: S. LeRoy RN, MSN
Reviewed by: E.Bove, MD
Reviewed January, 2010