Coronary Artery Bypass Grafting (CABG)

Coronary artery bypass grafting (CABG) is a type of an open heart surgery that intends to improve the flow of blood to the heart. It involves the placement of a coronary artery bypass graft, which is retrieved from a healthy artery in the body, and placed in the position of the blocked portion of the artery that supplies blood to the heart. CABG surgery is a complex, yet common procedure.

A waxy substance called plaque may deposit in good amount in the coronary arteries of the heart over a period of time. As time advances, the plaque starts hardening and eventually ruptures and breaks open. The plaque interferes with blood flow as arteries grow narrow at the affected region. A blood clot develops when the plaque ruptures. The artery may get blocked completely is the size of the clot is big enough to stop the flow of blood to the heart. This may eventually lead to serious events such as heart attack and also put the individual at the risk of death.

The person may experience chest pain and discomfort when the heart is deprived of rich oxygenated blood This pain is referred to as angina. Breathlessness and  fatigue are some of the other problems associated with coronary heart disease.

Coronary artery bypass surgery aims at improving the overall blood circulation to the heart. A part of healthy artery or vein from another part of the body is taken and is grafted or connected to the blocked coronary artery for bypass. This artery or vein goes around the blocked portion of the coronary artery and establishes a new path for the blood to flow to the heart, thus reducing the chance of a heart attack. In a single surgery, surgeons can bypass multiple coronary arteries. Severe blockages can be treated with this procedure.

CABG is conducted when there are one or two blockages in the artery. High risk CABG is conducted when there are multiple blockages in the artery and the blood flow to the heart is severely restricted.

There are two approaches to conduct CABG – open heart surgery and laparoscopic bypass heart surgery. The latter is a type of minimally invasive heart bypass surgery, which involves the creation of smaller incisions. This results in minimum discomfort and complications and allows for faster recovery and healing.

Laparoscopic bypass heart surgery is mostly preferred when there is not much blockage in the coronary artery. Open heart surgery, on the other hand, is conducted in complicated cases. High-risk CABG is mostly conducted as an open heart surgical procedure.

• The selection of a particular approach, however, depends on a number of factors, including the overall health of the patient and the experience of the surgeon. CABG involves the use of general anaesthesia. Typically, an incision down the middle of the chest is made by the cardiac surgeon. He then uses a saw like instrument to access the breastbone or the sternum. This cutting of the middle of the sternum is referred to as median sternonomy. During CABG, the heart has to be first cooled with iced salt water. Along with this, a preservative solution has to be injected in the arteries of the heart. This procedure is referred to as cardioplegia, where damage is minimized due to reduced blood flow to the heart during the surgery.
• A cardiopulmonary bypass must be established before a bypass surgery can take place. To channelize venous blood out of the body, plastic tubes must be placed in the right atrium. A membrane oxygenator, which is like a plastic sheeting, is employed to channelize it to the heart lung machine.
• The oxygenated blood is then returned to the body. To allow the bypass to connect with the aorta, the main aorta is cross clamped during the surgery. This maintains a bloodless field. Saphenous vein from the leg is the commonly used as coronary artery bypass graft.
• Beyond the narrowing of the vessel or the coronary artery, the graft vessel is sewed to the coronary arteries. The other end of the grafted vein or vessel is made to attach with the aorta. Nowadays, chest wall arteries or more specifically, the internal mammary artery is used as a coronary artery bypass graft.
• The artery is then separated from the wall of the chest to connect to the left anterior descending artery. It can also be connected to one of the major branches which is beyond the blockage.
• Internal mammary arteries have an advantage over venous grafts. The former remains open for a longer period of time. The percentage of being open in the case of venous grafts is around 66 percent, while for internal mammary arteries it is 90 percent.
• The aorta must be clamped off for 60 minutes while the body is supported by cardiopulmonary bypass. The use of 3, 4 or 5 bypasses has grown very common. At the end of the surgery, the sternum is wired together with the help of stainless steel while the incision made in the chest is sewn. Plastic tubes are kept undisturbed to allow any blood drainage from the region around the heart. The chest tubes are removed right after surgery along with the breathing tube.

Coronary artery bypass grafting (CABG) Recovery

Patients are transferred to the ICU right after the surgery and shifted to the patient ward a day later. Heart rhythm disturbances are discovered in 25 percent of the patients within a period of 3 or 4 days after the surgery. They are temporary atrial fibrillations associated with surgical trauma. Such patients respond well to standard medical therapies.

They can be weaned within a period of a month after the surgery. From one week to one day, the range of stay in the hospital may vary from one patient to the other. Young patients are usually discharged within two days. The recovery time can be very long and the range of physical activities must be kept to a minimum.