The blood vessels from the patient's own body, which he can spare, are used to perform these bypasses. The internal mammary arteries supply blood to the chest wall and the breast bone. The left internal mammary artery commonly known as the LIMA is used to bypass the LAD, which is the most important artery of the heart. The best results have been observed with use of this artery, which makes this the surgeon's favourite. The veins from the legs called the saphenous veins and the radial artery from the arm are also used. The surgeon studies the coronary arteries and tailors his plan of revascularization to suit the needs of the individual patient. Once the surgeon joins up or anastamoses the grafts, blood flows through them into the blocked arteries beyond the blocks thus bypassing them. The blocks are not removed but are bypassed, hence the name bypass surgery!
In the Conventional CABG the heart-lung machine is used to perform the operation. The heart-lung machine allows the heart's beating to be stopped, so the surgeon can operate on a surface, which is blood-free and still. The heart-lung machine maintains life despite the lack of a heartbeat, removing carbon dioxide from the blood and replacing it with oxygen before pumping it around the body.
Beating Heart bypass surgery allows surgeons to perform surgery on the heart while it is still beating. The heart-lung machine is not used. The surgeon uses advanced operating equipment to stabilize (hold) portions of the heart and bypass the blocked artery in a highly controlled operative environment. Meanwhile, the rest of the heart keeps pumping and circulating blood to the body