An artificial heart valve is a device which is placed in the heart of a patient with severe valvular heart disease that cannot be managed with medication therapy alone. The human heart contains four valves: tricuspid valve, pulmonic valve, mitral valve and aortic valve. Their primary purpose is to maintain blood flow through the heart and from the heart to the body. Any one of the four heart valves can stop functioning properly, and result in either stenosis (difficulty in opening the valve) or regurgitation (difficulty in closing the valve). This results in blood backing up into the lungs or heart, and the patient can develop serious symptoms of heart failure. Replacement of the diseased heart valve improves life expectancy, as well as quality of life in such patients.
1- MECHANICAL HEART VALVES:
Mechanical heart valves are made of strong artificial materials, and thus they last very long (most of these manufactured valves will last throughout the rest of the patients’ lifetime). But these patient are at a risk of developing blood clots due to the
valve; these clots can break off and cause complications like stroke and heart attack. Thus, patients who have mechanical heart valves should always be on medications to keep their blood thin (warfarin).
2- BIOPROSTHETIC HEART VALVES:
Bioprosthetic valve is produced using animals heart valves (e.g. pigs) or other animal tissues which are strong and flexible. These valves are not as long lasting as the mechanical heart valves, but there is no increased risk of blood clotting with these valves, and hence the patients' usually don't require long-term use of blood thinners. With time however, these bioprosthetic valves they tend to wear and their functioning deteriorates. Thus in patients with a long life expectancy, they might need to be replaced with a second new valve.
The choice between a mechanical vs bioprosthetic valve depends upon each patient's individual assessment. Patients with a longer life expectancy and those who can tolerate blood thinner usually receive mechanical valves, whereas those with a higher risk of bleeding receive bioprosthetic valves.
In most cases, heart valve replacement is an open heart operation i.e. the surgeon opens your chest to remove the damaged valve and replace it with new valve. In some cases, the damaged valve can be replaced through a small incision near the the breastbone called "minimally invasive surgery". Patients are thoroughly evaluated prior to surgery to ensure they are able to tolerate the surgery.
For people with severe aortic stenosis who cannot tolerate open heart surgery, there is a new procedure called transcatheter aortic valve replacement (TAVR) which does not require open heart surgery. In this procedure, a catheter (a tube that enters the body through a blood vessel) is used to replace the damaged heart valve.