Coronary artery bypass graft surgery
What is coronary artery bypass graft surgery?
Coronary artery bypass graft surgery (CABG) is sometimes used to treat coronary artery disease (CAD). CAD is the narrowing of the coronary arteries (the blood vessels that supply oxygen and nutrients to the heart muscle), caused by a buildup of fatty material (plaque) within the walls of the arteries. When plaque loosens and breaks off, a blood clot forms, which can block blood flow to your heart, resulting in chest pain or heart attack. If the blood flow cannot be restored to the particular area of the heart muscle affected, the tissue dies. If the blood supply to the heart muscle continues to decrease as a result of increasing obstruction of a coronary artery, a myocardial infarction (heart attack) may occur.
One way to treat the blocked or narrowed arteries is to bypass the blocked portion of the coronary artery with another piece of blood vessel. Blood vessels, or grafts, used for the bypass procedure may be pieces of a vein taken from the legs or an artery in the chest. At times, an artery from the wrist may also be used. One end of the graft is attached above the blockage and the other end is attached below the blockage. Thus, the blood bypasses the blockage through the new graft to reach the heart muscle.
Possible risks associated with coronary artery bypass graft surgery include:
- Bleeding during or after the surgery
- Blood clots that can cause heart attack, stroke or lung problems
- Infection at the incision site
- Breathing problems
- Cardiac dysrhythmias/arrhythmias (abnormal heart rhythms)
There may be other risks depending on your specific medical condition. Be sure to discuss any concerns with your doctor prior to the procedure.
There are two methods of CABG surgery: open (traditional) surgery and minimally invasive surgery. While the traditional "open heart" procedure is still performed and often is preferred in many situations, newer, less invasive techniques have been developed.
Traditional surgery (open heart surgery)
With traditional surgery, the chest is opened and the heart is stopped for a time so the surgeon can perform the bypass. To open the chest, the breastbone (sternum) is cut in half and spread apart (sternotomy). Once the heart is exposed, tubes are inserted into the heart so that the blood can be pumped through the body by a cardiopulmonary bypass machine (heart-lung machine). This type of surgery involves making long surgical incisions down the inner thigh and/or calf to harvest veins to be used for bypassing the blocked arteries.
To sew the grafts onto the very small coronary arteries, the heart must be stopped to allow the doctor to perform the very delicate procedure. Tubes will be inserted into the heart so that the blood can be pumped through your body by a cardiopulmonary bypass machine. Once the blood has been diverted into the bypass machine for pumping, the heart will be stopped by injecting it with a cold solution.
When the heart has been stopped, the doctor will perform the bypass graft procedure by sewing one end of a section of vein over a tiny opening made in the aorta, and the other end over a tiny opening made in the coronary artery just below the blockage. If the internal mammary artery inside your chest is being used as a bypass graft, the lower end of the artery will be cut from inside the chest and sewn over an opening made in the coronary artery below the blockage.
You may have more than one bypass graft performed, depending on how many blockages you have and where they are located. After all the grafts have been completed, the doctor will examine them to make sure they are working. Once the bypass grafts have been completed, the blood circulating through the bypass machine will be allowed back into your heart and the tubes to the machine will be removed. Your heart will be restarted. Temporary wires for pacing may be inserted into the heart. These wires can be attached to a pacemaker and your heart can be paced, if needed, during the initial recovery period.
Minimally invasive procedures
In the 1990s, "off-pump" procedures (OP-CAB), in which the heart does not have to be stopped, were developed. Instead, you are given medication to slow your heart rate during the procedure. Other minimally invasive procedures, such as keyhole surgery (performed through very small incisions) and robot-assisted procedures (performed with the aid of a moving mechanical arm), increasingly are being used.
Once the chest has been opened, the area around the artery to be bypassed will be stabilized with a special type of instrument. The rest of the heart will continue to function and pump blood through the body. The cardiopulmonary bypass machine and the perfusionist who runs it may be kept on standby should the procedure need to be completed with open surgery. The doctor will perform the bypass graft procedure by sewing one end of a section of vein over a tiny opening made in the aorta, and the other end over a tiny opening made in the coronary artery or internal mammary artery just below the blockage.
Two other procedural improvements are endoscopic vein harvesting and endoscopic radial artery harvesting. In both, surgeons use an endoscope (thin surgical tube with a light and camera on the end) to locate blood vessels that will be used for bypassing the blocked arteries. Veins are generally harvested from the inner thigh and calf areas of the legs, while the radial artery is harvested from the wrist.
Compared to traditional CABG, OP-CAB offers the patient less risk for complications including:
- Kidney failure
- Cognitive problems
Lenox Hill Heart and Vascular Institute surgeons are also some of the few in the New York City region that use multiple arteries instead of veins for bypass. Bypasses using arteries last longer and give superior long-term survival. According to a Society of Thoracic surgeons report, only 5 percent of heart bypass had two arterial bypasses used nationally; however, our surgeons use multiple arterial bypass in more than 70 percent of our patients.
How to prepare
Your doctor will explain the procedure to you and offer you the opportunity to ask any questions you might have. In addition to a complete medical history, your doctor may perform a complete physical examination to ensure that you are in good health before undergoing the procedure. You may undergo blood tests or other diagnostic tests. Based on your medical condition, your doctor may request other specific preparation.
Notify your doctor if:
- You are pregnant or suspect that you are pregnant
- You are sensitive to or allergic to any medications, iodine, latex, tape or anesthetic agents (local and general)
- You are taking prescription or over-the-counter medications or herbal supplements
- You have a history of bleeding disorders or are taking any anticoagulant (blood-thinning) medications, aspirin or other medications that affect blood clotting
- It may be necessary for you to stop some of these medications prior to the procedure.
- Your doctor may request a blood test prior to the procedure to determine how long it takes your blood to clot.
- You have a pacemaker
- You smoke (you should stop smoking as early as possible prior to the procedure)
You should not eat for eight hours before the procedure, generally after midnight.
Coronary artery bypass surgery requires an in-hospital stay of several days or longer. The procedure may vary depending on your condition and your doctor's practices. Once you're at home, it will be important to keep the surgical area clean and dry. Your doctor will give you specific bathing instructions. The sutures or surgical staples will be removed during a follow-up office visit if they were not removed before you left the hospital.
You should not drive until your doctor says you may. Other activity restrictions may apply. Your doctor may give you additional or alternate instructions after the procedure, depending on your particular situation.
Notify your doctor if you experience any of the following:
- Fever and/or chills
- Redness, swelling, or bleeding or other drainage from the incision site
- Increase in pain around the incision site