Evaluate the use of mechanical replacement heart valves and biological replacement heart valves. (6 marks)

Types of Replacement Heart Valves. ... A tissue heart valve is made of biological tissue, usually from an animal, and can last about 10 to 20 years. While tissue valves are not as long-lasting as mechanical valves, they do not usually require long-term use of blood thinner medicines. Advantages of tissue valves compared to mechanical valves include the avoidance of lifelong warfarin therapy to prevent the development of blood clots. A disadvantage is their relatively poor durability compared to mechanical valves, with many requiring a re-operation in 10 to 20 years.