You've undoubtedly heard it said -- the human body is an amazing machine. But as amazing as it is, there are times when disease, injury or extensive wear and tear leaves it working at a less-than-efficient and even dangerous level. Such is the case with the heart and its valves.
There are four valves of the heart which ensure that blood flows in the right direction at the proper rate and that blood flow is stopped when necessary. The valves are the aortic, mitral, pulmonary and tricuspid valves [source: Mayo Clinic]. If any of the valves in your heart become rigid, fail to completely seal or get stretched out over time, your quality of life will suffer to one degree or another. It could be something as seemingly minor as periodic fainting or it could lead to a life-threatening heart attack. In any case, you may one day find yourself in need of valve replacement surgery [sources: MedlinePlus; HealthGrades]. Artificial valves come in two primary forms -- biological and mechanical. Each option carries its own risks and advantages. Your doctor will take your age and lifestyle into account before determining which choice is best for you [source: Aranki].
Heart valve replacement surgery was first introduced 50 years ago as an option for patients suffering from heart disease [source: Aranki]. As of 2011, in the United States alone, approximately 70,000 to 80,000 valve replacement surgeries are performed each year [source: Harvard]. Heart surgery always carries risks that can range from bleeding to an irregular heartbeat to stroke and heart attack [source: Mayo Clinic]. Today, however, artificial valve replacement surgery has a high rate of success [source: MedlinePlus].
But not all valves are the same. Next, we'll look at different types of mechanical heart valves.