Valve replacement refers to the surgical replacement of one or more of the four valves in the heart that control the direction and flow of blood. It is performed as an open-heart surgery with the patient being kept under general anaesthesia. The blood from the heart is re-routed via a heart-lung bypass machine while the heart is operated on.
People with cardiac problems that would require valve replacement may suffer from chest pain, a sensation of feeling the heart beat, shortness of breath or difficulty breathing after engaging in physical activities, coughing and fatigue. A patient may gradually develop these symptoms or experience them simultaneously.
Valve replacement is performed to rectify the following conditions:
- Stenosis (narrowing of the heart)
- Regurgitation (leaking of the heart valve)
Patients may be treated by valve replacement using one of two types of valves: a metal or mechanical valve, and a tissue or biological valve. The mechanical valves last a lifetime and are usually made from metal and pyrolytic carbon. To prevent blood clotting, patients are required to take blood-thinning medications.
Tissue valves only last for about 10 or 15 years, but they do not require the patient to take blood-thinning medication. The choice of valve is determined by a patient and their doctor while taking the following aspects into consideration: age, lifestyle, medication preferences and medical condition.
A number of risks exist around valve replacement. When under anaesthesia, patients may have negative reactions to medications or have problems breathing.
Patients risk excessive bleeding and infection when undergoing surgery. Other risks associated specifically with cardiac surgery include stroke, heart attack, arrhythmia, kidney failure, temporary post-operative confusion (due to use of the heart-lung machine) and death.
Infections can also result in valve replacement becoming necessary. Conditions like rheumatic fever, birth defects or calcification can cause valve problems. If defective valves are not treated, conditions like congestive heart failure (for mechanical reasons) or additional infections may arise. Diseased or abnormal valves are a preferred site for bacteria in the blood to settle and breed. The result is a growth on the valve, or bacteria and inflammatory tissue.
This condition is called Infective Endocarditis, and may be life-threatening. Not only is valve function disrupted by the growth on the valve, but the patient can become critically ill. Bits of the septic growth can break off and be carried in the blood to other parts of the body, where they cause septic emboli. Brain abscesses can result from this condition.
Surgery in the presence of Infective endocarditis is very risky, but may be the only option in some cases.
Valve replacement surgery has a high success rate. Depending on the heart valve, the death rate averages 2% and 5%. On average 2 out of 3 patients who received an artificial mitral valve are still alive 9 years after their surgery.
Patients usually stay in the intensive care unit for 2 to 3 days after the operation where their heart functions will be constantly monitored. The average amount of time spent in hospital is 1-2 weeks. Depending on a patient's health before the surgery, complete recovery can take anywhere between a few weeks and several months.
After valve replacement, all patients must follow a specific antibiotic regime: any surgical procedure, no matter how minor, including ALL dental work (even cleaning by the hygienist) must be covered by antibiotics, taken an hour before the time. There is a specific protocol, which patients can obtain from their cardiologists.
For those with mechanical valves, Warfarin is used for life. This means regular monthly (at least) blood tests to measure the INR. The INR indicates the amount of anti-coagulation achieved in a patient, and will determine any adjustment needed in the dosage.