There are 4 valves in heart which ensure smooth blood flow from one chamber to another chamber and that too only in forward direction. Some times they get diseased – resulting in either the narrowing of the valve causing obstruction to forward flow or the leakage of valve leading to the blood flowing in the reverse direction also. Commonly, valves on the left side (the mitral valve between the left upper and lower chambers, and the aortic valve between the left lower chamber and the aorta) are affected. Common diseases that affect valves are:
When they are affected, heart will not be able to pump adequate blood to other tissues in the body. If there is not adequate improvement with drugs, they may need surgery. Some times the surgeon may be able to repair the native valve releasing the obstruction or leak. If repair is possible, preserving native valve has its advantages. Some times that valve needs to be replaced by an artificial valve. Commonly one of the two artificial valves is used.
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Metallic Valves (Figure1): These valves made of metal last very long. But they need careful maintenance. Blood is likely to clot on them. These clots may block the valve causing death, or small clots may travel to brain producing stroke and other complications. So the patient needs to take special drugs—anticoagulants (blood-thinning agents) lifelong. Their dose is adjusted according to a blood test called INR. We need to keep the value between 2.5 and 3.5. If the dose is higher, it may cause bleeding in brain or other areas. The patient has to avoid green leafy vegetables, which contain vitamin k (this promotes blood clotting). Whenever the patient is going for any surgery like dental extraction or develops infections in the body the patients need to contact his/her cardiologist or heart surgeon. We usually recommend metallic valves for people aged less than 50 years.
Tissue Valves (Figure2): These are valves taken from pigs or made from tissues of other animals like cows, but rarely taken from human beings. The advantage with them is you do not need to take blood-thinning agents lifelong. Even if one forgets drugs for a day or two, normally nothing happens. A patient does not need frequent visits to doctor or blood tests, unlike a patient with metal valves. Generally, tissue valves last 10 to 15 years. So we usually recommend them for patients aged more than 50-55 years. In future, patients with tissue valves or those who have undergone repair may need one more surgery.