Artificial heart valves can be biological or mechanical. Biological valves are made of human or animal tissue (cow and pig hearts are often used) and usually have a shorter life span than mechanical valves. Mechanical valves, however, require the patient to take anti-coagulant medication continually to prevent blood clots [source: HealthGrades]. If you're a younger patient it's likely your doctor will recommend a mechanical valve because of its durability. The exception to this rule is younger patients who are seeking to get pregnant or are highly active and prone to injuries that could result in bleeding. In either case, the blood-thinning medications used after replacing a valve with a mechanical device could pose problems which would make a biological valve a better choice [source: Harvard].
Mechanical valve options have evolved with time. The first commercially available option was a ball-and-cage design [source: Aranki]. As blood flows, the ball is pushed forward to open the valve, yet the cage restrains the ball from moving too far. Likewise, as blood flow decreases the ball rolls back into place to close the valve and prevent regurgitation. The ball-and-cage structure can be made of ceramic, steel or titanium [source: MedlinePlus].
In recent years, a mechanical valve which uses leaflets has become increasingly popular [source: Aranki]. The leaflets are like flaps that open and close with the beating of the heart. Think of them as windows that open in one direction but not the other. Leaflet valves may come with two or three leaflets per valve, and are named bileaflet or trileaflet valves accordingly.
Mechanical valves are extremely durable, but biological valves need to be replaced after 10 to 15 years [source: Harvard].
As you might guess, swapping out heart valves isn't easy. Next, let's examine several heart valve replacement procedures.