You mean malfunction
The aortic valve has 3 parts or leaflets.
When its called bicuspid it has only 2 leaflets. This can be congenital or aquired. If two of the cusps fuse over time is called functional bicuspid vs congenital. Either way it creates an un natural flow across the valve and over time damage the valve. Most often the valve will need replace depending on age diagnosed.Most congen bicuspids will need repla.