The technology for replacing human heart valves with mechanical or tissue valves, like those from pigs, has evolved steadily since the 1950s. The former option is more durable, while the latter provides greater freedom from lifelong medication.
Heart valve replacement surgery repairs damaged valves inside the heart that control the flow of blood. Of the four major valves, the aortic or mitral valve is replaced in the great majority of surgeries.
Types of Valves
There are two primary types of artificial valves. Biological valves come from cadavers, cows or pigs, while mechanical valves can be made of metal, carbon or synthetic materials.
The downside of mechanical valves is the necessity of taking the blood-thinning medication warfarin for life. However, mechanical valves are sturdier and decrease the likelihood that the patient will need surgery again to replace them.
Biological valves, also called tissue valves, can come from a pig (porcine valve), cow (bovine valve) or cadaver. While these are commonly used, their lifespan is usually limited, and an additional valve replacement may be necessary 10 to 15 years after the initial procedure. With a biological valve, though, long-term use of warfarin may not be necessary.
How does one choose between a biological and a mechanical heart valve? "Mechanical and biological valves each have advantages and disadvantages," says Dr. J. Michael Duncan, a cardiovascular surgeon with the Texas Heart Institute. "You will have to make that decision for yourself."
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