Coronary Artry Bypass Grafting (CABG) is nowadays generally performed in patients who are unsuitable for Coronary Angioplasty. This is usually because of the numbers and complexity of the narrowings or blockages in the coronary arteries. With some patterns of heart disease there is evidence that patients will do better after bypass surgery when compared with angioplasty.

The bypass operation is carried out under general anaesthetic. The chest is opened though the breast bone. The lungs collapse and the blood is passed though a heart bypass machine that puts oxygen into the blood and removes carbon dioxide. The bypass machine then pumps the oxygenated blood around the body. The heart is thus temporarily removed from the circulation allowing the heart to be stopped and the surgeon to operate.

The surgeon usually uses a length of vein removed from the patient's leg. One end of the vein is connected to the aorta, the main artery carrying blood from the heart to the body. The other end of the vein is attached to the coronary artery beyond the narrowing or blockage - so constructing a bypass graft taking bood around the narrowing / blockage. In the UK the usual number of grafts inserted is about three. For one of these the surgeon usuall tries to uses an artery that runs just behind the breast bone - the Left Internal mammary artery. The top end of the artery is attached to an artery near the left shoulder. This is left intact and the lower end of the mammary artery is usually attache dto the artery that supplieds the front wall of the heart. This bypass graft tends to last even longer than vein grafts.

At the end of the operation, the heart is restarted and the normal flow of blood is reestablished.

After the operation the patient spends 1 - 2 nights in intensive care. Initially they are on a ventillator machine but usually quickly take over breathing normally. Some drugs may be used for a period to help the heart but usually these can be stopped within a couple of days. The next 5 - 6 days are spent getting back to walking and getting about on the ward. Patients usually leave hospital about 7 days after the operation.

There is a period of a few weeks getting back to normal at home after this. Patients usually get back to work about 6 weeks after surgery.

Although this is a general description of bypass surgery there are techniques used in some patients that differ in their details.