Newborns with significant AS develop CHF within the first week of life. The left ventricle is often too small to be compatible with life. Congenital AS caused by a congenital unicuspid or bicuspid aortic valve is usually asymptomatic in the otherwise healthy developing child. It often is diagnosed on routine physical examination, although a child may present with angina pectoris with exercise. These patients have a fibrous contracture with shortening of the cusps due to recurrent inflammation from rheumatic carditis.
Adjacent cusps tend to fuse at the commissures.
This causes a form of acquired unicuspid or bicuspid aortic valve. Calcifications may develop, but the primary cause of stenosis is the adhesions that fuse the cusps. In patients older than 70 years, the most common cause of AS is degenerative calcification of the valve. Monckeberg senile calcific AS occurs in elderly patients in whom all 3 cusps are highly calcified. Calcific AS also occurs in older patients with congenital or acquired bicuspid valves.