Coronary Artery Bypass Graft
Coronary artery bypass surgery (CABG), also coronary artery bypass graft surgery and heart bypass, is a surgical procedure performed on a person who has coronary artery disease that is not amenable to PTCA and/or Stenting. This generally helps in the relief of angina and possibly improve the patients heart muscle function. Veins or arteries from elsewhere in the patients body are grafted from the aorta to the coronary arteries, bypassing the narrowings caused by atherosclerosis and improve the blood supply to the heart muscle.
First, the sternum is cut down the middle with a special bone saw and the chest opened.
Depending on a number of factors, the surgeon may decide to place the patient on cardiopulmonary bypass ("on-
Blood vessels are harvested from elsewhere in the body for grafting.
Sometimes artery end branches supplying tissues near the heart are rerouted to create the bypass.
Typically, the left internal mammary artery (LIMA) or right internal mammary artery (RIMA )are used for bypass. If additional bypasses are required the great saphenous vein from the leg is frequently used.
Veins that are used either have their valves removed or are turned around so that the valves in them do not occlude blood flow in the graft. LIMA / RIMA grafts are longer-
Alternatively, an artery such as the radial artery from the arm or gastroepiploic artery from the stomach, may be used in place of a vein, however, these are not common practices today.
About Coronary Bypass
The goal of coronary artery bypass graft surgery (CABG) is not to repair or remove any blocked arteries, but to detour blood around a blockage in a coronary artery and reestablish the flow of oxygen–rich blood to the heart. To create the detour, a segment of a blood vessel is taken from another part of the body. The segment may be taken from one of the following:
The saphenous vein from the leg is commonly used.
The internal mammary artery from the chest is usually preferred for key artery branches because it tends to remain open longer. Some call it the internal thoracic artery.
The radial artery from the arm and sometimes arteries from the stomach (gastroepiploic artery) may also be used as bypass grafts.
Coronary Artery Bypass Graft
Depending on which blood vessel is used, one end is either sewn to the aorta or may remain connected to the larger artery where it originated. The other end is attached (grafted) beyond the blockage in the coronary artery. As a result, blood can flow around the blocked area, increasing the supply of oxygen and nutrients to the heart muscle.
Bypass surgery may be recommended for individuals with a history of any of the following:
Narrowing in several coronary artery branches (common in people with diabetes)
Severe narrowing in the left main coronary artery
Blockage in the coronary artery or another condition that may not or has not responded to other treatments (e.g., angioplasty)
Bypass surgery carries some risks, including a less than 5 percent chance of heart damage and a less than 2 percent chance of death. Studies show that women have a slightly higher risk during or immediately after bypass surgery. This may relate to the fact that women who undergo the surgery are generally older and in poorer health, and their smaller body size makes the surgery technically more difficult. However, the overall risks are relatively low when compared to the fact that many of these bypass operations significantly lengthen and improve the quality of the patient’s life.
In some cases, the grafted arteries may also become blocked and require a second bypass surgery. Second bypass has slightly higher risks than the initial surgery, because patients are older and other, less optimal blood vessels must be used for the new grafts. However, bypassed arteries can remain functioning for many years, especially when the patient makes diet and exercise adjustments for cardiac health. Therefore, bypass surgery remains a popular choice for physicians treating severe coronary artery disease.
The above picture shows the vein grafts and the drainage tubes (temporary placement – drains excess fluids in the chest cavity post procedure)
Once the vein grafts and/or the LIMA is attached and the procedure completed the sternum is closed using steel wire to hold the sternum together. This remains in the patient for the rest of his / her life and is clearly visible under fluoroscopy / xray. The picture below shows the chest closed with the temporary drainage tubes in place. These tubes are removed a couple days later.
The skin surfaces is sutured together using normal stitches to close up the incision. A piece of dressing is placed over the incision site.
The patient is then sent to the Cardiac ICU.