There are four valves in your heart and the job of each valve is to make sure that blood flows in the correct direction. If one of your valves doesn't open or close properly, it can affect your blood flow by either obstructing the flow of blood to the rest of the body or leaking blood back into the heart. If this happens, surgery to replace the valves may be recommended, although many people with heart valve disease need little or no treatment.
Leaking valves can sometimes be repaired but other diseased valves will need replacing. The most common types of replacement valves are mechanical (manufactured) valves or tissue (animal) valves.
During surgery, a cut is made in the chest to access the heart. In a very small number of cases, a smaller incision can be made in your chest, so that your breastbone doesn't need to be cut. This is called minimally invasive surgery.
The heart is then stopped and a heart-lung bypass machine is used to take over the circulation during the operation. The aortic valve is then removed and replaced with an artificial valve. The heart is then started again and the incision in the chest is closed.
Like all operations, valve surgery isn't risk free and major surgery can be life-threatening. Your own risk will depend on your age, current state of health and the degree of valve disease.
Around 1 in 50 people who undergo this type of surgery die from complications during or shortly after surgery. However, untreated, there is a much higher risk of dying. Each case is carefully selected and the benefits of aortic valve replacement will usually far outweigh any associated risk of surgery.
Most people are sitting out of bed a day or two after their operation, and return home within about a week. On average, it takes most people between 2-3 months to fully recover, but this can vary greatly as it depends on your individual condition and how old you are.
One way of improving blood supply to the heart for people with narrowed arteries is to graft arteries and veins from elsewhere on the body to the coronary arteries to bypass these narrowings.
It's a good way of reducing chest pain and reducing the risk of a heart attack although patients also need to make lifestyle changes to reduce the chance of the grafted arteries also narrowing.
The surgeon takes a blood vessel from another part of the body, and attaches it to the coronary artery above and below the narrowed area or blockage.
In most cases, at least one of the blood vessels used as a bypass graft is an artery from your chest. Blood vessels such as a vein from your legs or an artery from your arms may be used for other grafts. Usually, the surgeon will carry out several grafts (referred to as double, triple or quadruple bypasses) to make sure the procedure does not have to be repeated in the future.
Surgeons usually make a cut down the middle of the breastbone to reach your heart. But in some operations the breastbone doesn't need to be cut (minimally invasive surgery).
A heart-lung bypass machine circulates the blood around your body while the surgeon operates on your heart, but some surgeons carry out coronary bypass operations without this machine.
As with all surgery, especially major surgery, bypass surgery carries a risk of complications. The risks increase according to various factors such as age, health and complexity of the operation.
Both the heart and the coronary arteries that supply the heart with blood are in a vulnerable state after surgery, especially in the first 30 days after surgery. An estimated 7% of people will have a heart attack in this period although most people will recover.
After your operation you will be moved to intensive care for close monitoring until you wake up. Once your condition is stable, you will be moved to the high dependency unit or the cardiac ward.
You should be out of bed in a day or two and return home after a week. Full recovery takes two or three months, depending on your fitness, age and how severity of the problem.