Coronary artery bypass graft surgery is one of several major advances in the effort to manage cardiovascular disease—the leading cause of death and disability in the United States. You may have heard this surgery referred to simply as “bypass surgery” or as CABG (pronounced “cabbage” and short for “coronary artery bypass graft”).

Coronary bypass surgery is used to treat heart attacks or serious chest pain (angina) caused by blockages in the arteries that supply blood to the heart muscle. The surgeon attaches (grafts) a blood vessel taken from elsewhere in the body to the diseased heart artery, rerouting blood around the blockage in the same way a road detour re-routes traffic around road construction. A double, triple or quadruple bypass refers to the number of heart arteries that are bypassed.

The surgery carries many benefits, including some particularly for patients who have serious cardiovascular disease. The operation can save your life if you are having a heart attack or are at high risk of having one. If you have ongoing angina and shortness of breath from diseased heart arteries, elective coronary bypass surgery is highly effective at eliminating or reducing discomfort. Coronary bypass surgery can give you your life back.

Because coronary bypass surgery is an open-heart procedure requiring general anesthesia and in many cases that the heart is stopped during the operation, bypass carries risks. The good news is that recent decades have seen a steep drop in serious complications. Today, more than 95 percent of people who undergo coronary bypass surgery do not experience serious complications, and the risk of death immediately after the procedure is only 1–2 percent.

The risk of serious complications is higher for emergency coronary bypass surgeries, such as for patients who are having a heart attack, when compared to elective surgery for treatment of angina and other symptoms. Additionally, patients may be at higher risk if they are over 70 years old, are female or have already had heart surgery. Patients who have other serious conditions, such as diabetes, peripheral vascular disease, kidney disease or lung disease, may also be at higher risk.

While complications from coronary bypass surgery are relatively rare today, your care team will make every effort to guard against them and to treat them if they do develop. They may include the following:

• Risk of bleeding from site of attached graft and other sources. About 30 percent of patients will require blood transfusions after the surgery. Very rarely, bleeding will be severe enough to require additional surgery.
• Heart rhythm problems. Atrial fibrillation (a condition in which the upper chambers of the heart quiver rather than beating properly) is a common complication of coronary bypass surgery and can contribute to blood clots that form in the heart and that can travel to other parts of the body. Other forms of heart rhythm problems are possible as well, though less common.
• Blood clots. If blood clots form, they can cause a heart attack, stroke, or lung problems.
• Infection at the incision site where the chest was opened for surgery. This complication is rare, occurring in only about 1 percent of coronary bypass patients.
• "Post-pericardiotomy syndrome." This condition occurs in about 30 percent of patients from a few days to 6 months after coronary bypass surgery. The symptoms are fever and chest pain.
• Kidney, or renal, failure. Coronary bypass surgery may damage the functioning of a patient’s kidneys, though this is most often temporary.
• Memory loss or difficulty thinking. Many patients report difficulty thinking after coronary bypass surgery. This problem typically improves in 6 months to a year. Researchers are not sure what causes this, though one theory is that the use of a heart-lung machine to allow surgery on the heart dislodges tiny bits of fatty build-up in an artery that can travel to the brain. Studies have been inconclusive about whether surgeries on a beating heart and without the heart-lung machine reduce this complication.
• Reactions to anesthesia. As with any surgery performed while the patient is “asleep,” patients may have reactions to the anesthesia, including difficulty breathing.
• Death. In-hospital death is very rare after coronary bypass surgery. It is typically caused by heart attack or stroke.

If you are considering coronary bypass surgery on an elective basis to treat your heart disease, please discuss any concerns you have about balancing the benefits and risks of the surgery with your cardiac surgeon. To help you start this conversation, consider downloading Questions to Ask Your Doctor About Coronary Bypass Surgery.

Learn More

If you’d like to learn more about cardiovascular conditions, follow the links below:

• Coronary Artery Disease. Blockages form in the heart arteries as a result of a progressive disease process. If you have had or are being recommended to have coronary bypass surgery, it is to treat your underlying coronary artery disease.
• Angina/Chest Pain. Coronary bypass surgery is one treatment option for non-heart-attack chest pain caused by a lack of blood flow through arteries leading to the heart muscle. This chest pain is called angina. Treatment can restore your ability to enjoy everyday activities.
• Heart Attack. Heart attack patients who have blockages in certain locations in heart arteries or who have blockages in multiple blood vessels and diabetes may be better candidates for coronary bypass surgery than less invasive angioplasty and stenting. Understanding the mechanisms behind a heart attack can help you understand how treatment works.
• Diabetes & Your Heart. Diabetes and cardiovascular disease, unfortunately, often go hand in hand. Coronary bypass surgery is the preferred treatment for patients who have diabetes and blockages in multiple heart arteries.