Introduction:
Aortic valve replacement is a procedure performed to treat a disease, in the valve between the left ventricle and the base of the aorta (aortic valve). If the aortic valve does not close properly, blood does not maintain a one-way flow, leaking back into the heart from the aorta. This is called aortic regurgitation. However, if the valve does not open fully, blood cannot flow out of the heart into the aorta properly; this is called aortic stenosis.
How is it Performed?
Traditionally, the central chest bone is split (sternotomy) and the heart is stopped using a Heart-Lung bypass machine. The diseased valve is then replaced using either kind of artificial valve. The sternum is closed using steel wires that can remain in the body. Valve replacement can also be done through a minimally invasive approach, this is discussed in detail overleaf.
The 2 Types of Artificial Valves:
1) MECHANICAL VALVE - Made of pyrolite carbon. Hinges in these valves enable the leaflets to open smoothly. These valves are usually used In young patients.
Advantage:
Usually lasts throughout the patient's life.
Disadvantage:
1. Patients need to take anti-coagulation tablets, to keep the blood thinner than normal.
2. This prevents clot formation in the valve's hinges or leaflets.
3. Anti-coagulation levels need to be monitored closely and maintained within specified limits.
4. Improper blood thinning can lead to major complications. such as stroke or fatal bleeding within the body.
2) TISSUE VALVE - made from specially prepared animal heart tissue. These valves are usually used in older patients.
Advantage:
1. No anti-coagulation medication is required; all anticoagulation-related problems are thus alleviated.
Disadvantage:
1. Animal tissue degenerates with time.
2. Most patients will need a repeat surgery to replace the valve again in 10-20 years.
3. The time taken for the tissue valve to degenerate depends on the valve used and the age of the patient.
