Aortic valve, bicuspid: Whereas the normal aortic valve in the heart has three flaps (cusps) that open and close, a bicuspid valve has only two. There may be no symptoms in childhood, but in time the valve may become stenotic (narrowed), making it harder for blood to pass through it, or the valve may start to let blood leak backwards through the valve (regurgitate). Treatment depends on how the valve is working and overall condition of the affected individual.