During this procedure, one or more narrowed coronary arteries are bypassed using blood vessels from the legs or chest. The operation takes about 2 hours. In most cases, the heart is stopped and a heart–lung machine is used to take over the function of the heart during surgery (see Surgery using a heart–lung machine). However, an increasing number of operations are performed without stopping the heart (sometimes known as “off-pump” coronary artery bypass grafting), and less invasive techniques using endoscopic surgery are also being used more commonly. After surgery, you will be monitored in an intensive therapy unit for several days.
If there is only one blockage in a coronary artery, one of the internal mammary arteries within the chest, usually the left artery, is used to create the bypass. Artery grafts are preferable to vein grafts because they are better able to take the pressure of the blood that normally flows through the coronary arteries and are less likely to become blocked over time.
The left internal mammary artery is cut where shown above. The upper end is left attached to the subclavian artery and the lower end is tied off.
The free end of the mammary artery is connected to the coronary artery at a point beyond the blockage to supply blood to the heart muscle there.
If more than one blockage in a coronary artery needs to be bypassed or if the internal mammary artery is not suitable, sections of the saphenous vein may be used. Often, the vein is used in addition to the mammary artery. Because veins tend to become obstructed more quickly than arterial grafts, sometimes the radial artery from the forearm is used to create the bypass graft.
A long incision is made down the leg and the saphenous vein is removed. The vein is then divided into sections so that several coronary arteries can be bypassed.
Sections of the saphenous vein are used to bypass the blockages. One end of each section is attached to the aorta, and the other is attached to the coronary artery beyond a blockage.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.