Many problems can interfere with the proper functioning of a valve. They may be congenital (abnormal from birth), infectious (endocarditis), inflammatory (rheumatic fever), or just wear and tear over the years. In general, heart valve problems take one of two forms:

Stenosis

describes the condition when a valve does not open completely or the opening is too small, resulting in restricted blood flow

Regurgitation (a.k.a. Insufficiency)

implies that blood leaks backward across the valve that should be closed.

Some valves have both problems to varying degrees. Because the Ross Procedure is primarily an aortic valve operation, this text focuses on problems pertaining to the aortic valve.