Doctors in the United States perform more than 70,000 heart valve replacements each year. From birth, an individual may have an abnormal heart valve that requires replacement due to accelerated wear and tear (e.g., this happens with bicuspid aortic valves), or valve damage may occur following an infection or as an extension of damage to the adjacent heart muscle.
Most commonly, valve replacement develops from the consequences of bacterial throat infections, such as Strep throat. In the body's attempt to fight off the bacterial infection, the heart valves, as innocent bystanders, sustain damage (called rheumatic heart disease). With the use of antibiotics, rheumatic heart disease occurs less commonly today, but individuals who had this problem during childhood may now, as adults, experience the consequences of the damage to the valves.
Fitness and Diving Issue
Anyone who has had heart surgery should be scrutinized a little more carefully regarding medical fitness to dive. With a properly functioning heart valve and no symptoms of cardiovascular disease, the real concern for a diver with an artificial heart valve is the anticoagulation (blood thinning) medication required to keep the valve functioning.
A mechanical valve (made of metal, polymer etc.) requires medication to keep blood clots from forming on the valve. This, of course, increases the risk of bleeding, and the diver needs to be aware of this risk, especially as it relates to trauma. Heart valves from pigs are also used to replace damaged native valves. These do not require anticoagulation medication, but they wear out sooner and require replacement earlier than mechanical valves.
For more information on cardiovascular conditions, see the complete article by Dr. James L. Caruso on Cardiovascular Fitness and Diving from the July/August 1999 issue of Alert Diver.