The heart has four chambers and blood is pumped throughout these chambers with help from heart valves. Normally, these valves open fully to let blood flow in only one direction and then close completely. However, due to heart defects, infections, or rheumatic fever, a valve can become damaged and fail to open or close fully. One way of treatment is replacing the valve with one of two types of artificial valves, mechanical or biological.
Biological valves come from different animals and are a lot more similar to human valves than mechanical. The two different types of biological valves include an implantation of a porcine valve or the use of biological tissue to create new leaflets for the valve. The porcine (or pig) valve is very similar to human valves and is the best fit for a human heart. This full implantation is known as xenograft or the "transplant from one species to another". However this is not the best form of biological valve replacement because the body tends to reject the replacement as foreign material and medication does not always help. The second type of biological valve replacement is usually more successful and more reliable. This type uses biological tissue usually of bovine (cows) or equine (horses) to make new cusps that are sewn into a metal frame. This is very effective because the tissue is strong, flexible, and durable. It is also sterilized to minimize the rejection from the body's immune system. Also, unlike the mechanical valves, the patient is not required to stay on blood thinners or take anticoagulation therapy making it the best recommendation.
http://www.americanheart.org/presenter.jhtml?identifier=4598
http://en.wikipedia.org/wiki/Artificial_heart_valve
2 comments:
Are there any advantages to the porcine implant? Cost differences or other medical differences? I agree with your choice though... there seem to be less risks with the bovine implant.
thats really interesting. i didnt know the part about the other animals that they take valves from. nice paper
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