Bicuspid Aortic Valve

Worldwide, the most common adult congenital heart defect is a bicuspid aortic valve, as it is present in about 2 to 3 percent of the general population. The aortic valve is typically composed of three cusps or leaflets. As the valve opens with the contraction of the heart, blood is pumped to the brain and other vital organs. A bicuspid valve is composed of two cusps instead of three.
Most people can live many years with a bicuspid aortic valve and never know it is present. The most common cause of symptomatic aortic stenosis in a patient under 65 years of age is the narrowing of a bicuspid aortic valve. It is often detected when a doctor hears a loud murmur. A normal aortic valve has an opening of about 4cm2; patients don't usually have symptoms until the valve opening is less than 1cm2.
The valve is placed under an increased amount of hemodynamic stress and accelerated calcification, which causes damage and eventually narrows the opening. Some patients will also have an abnormal enlargement of the aorta, which can cause the valve to be both narrowed and leaky (combined stenosis and regurgitation).
In 20 percent of patients with bicuspid aortic valve, other congenital heart defects are recognized--patent ducutus arteriosus (PDA) and coarctation of the aorta. These combined disorders can result in symptoms sooner than the bicuspid valve. Symptomatic bicuspid aortic stenosis presents similarly to calcific aortic stenosis. Patients often experience chest pain, blackouts and eventually heart failure.
A bicuspid valve is also prone to infection (endocarditis) and requires prophylactic treatment with antibiotics before dental work. If a patient has an associated abnormality like a PDA, the risk of endocarditis is high.The prognosis is best if the valve is replaced at the onset of symptoms, before the muscle pump has been affected. The choice of treatment is surgery in the vast majority of cases.
In rare cases of pediatric bicuspid aortic stenosis, balloon valvuloplasty is an acceptable form of treatment with good long-term results. Since this is a disease process that affects younger patients, valve replacement with a mechanical valve is a serious issue, as it will commit a person to a lifetime of anti-coagulation with warfarin.