Donated human heart valves have many advantages over artificial or animal alternatives.
They are more resistant to infection and mean the recipient does not need to take blood thinners which can be especially dangerous in the young and may make pregnancy impossible.
Donated heart valves are used to repair congenital defects in babies and to replace diseased aortic valves in adults. They are also silent, unlike mechanical valves which tick.
They are as close as possible to a normal functioning heart valve and allow patients to live normal lives.