Heart valves are structures within the heart that facilitate the flow of blood in one direction and prevent blood from leaking back in the opposite direction. Valve problems may occur if the valve is too narrow (stenotic) or incompetent (leaky). If severe, the valve may need to be replaced with a new valve (valve replacement surgery) or in some cases, the existing valve may be operated on and corrected without the need for a new valve (valve repair). If valve replacement surgery is required, the existing valve is changed to an artificial valve which can be made of metal, plastic, or a biologic material made from animal or cadaveric tissue. Heart valve surgery is a major operation requiring at least 1 week’s stay in hospital and 6-8 weeks to fully recover.