Aortic valve is a heart valve that controls the blood flow between left ventricle and aorta. Aortic stenosis occurs when valve leaflets become deformed, thus obstructing blood flow to other organs including the heart itself. Rheumatic heart disease is the most common cause of aortic stenosis (AS) in developing countries. In developed countries, an old aortic valve with built-up calcification is the most common cause of AS.
Aortic stenosis is severe when the calculated area of the valve is less than 1cm2. The measurment of the valve area is performed indirectly by measuring the blood flow and pressure gradient across the valve. Doctors usually recommend either echocardiography or cardiac catheterization to measure the area of valve, depending on whether the pumping power of left ventricle is normal or weak.
Patients with severe AS are considered candidates for valve replacement operation if they develop chest pain, pass-out, or heart failure. However, the 2006 American Heart Association (AHA) guidelines concluded that valve replacement should not be performed routinely in patients without aforementioned symptoms. There are exceptions when surgery is still recommended in patients without symptoms.
The 2007 AHA guidelines no longer recommended routine antibiotic prophylaxis before dental or invasive procedures for patients with AS.
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