What Is Cardiac Bypass Surgery?

Cardiac bypass surgery is an operation to restore the flow of blood through the arteries that supply blood to the heart, when a blockage or partial blockage occurs in these arteries.

The arteries that supply the heart muscle with oxygen and nutrients are known as the coronary arteries. The word "coronary" means a crown, and is the name given to these arteries that circle the heart like a crown. The narrowing of the arteries of the heart is known as coronary artery disease, which is the most common form of heart disease.

The operation, also known as a coronary artery bypass graft (CABG), involves rerouting the blood flow around the obstructed part of the artery. This is done by using a portion of a blood vessel taken from another part of the body, usually the leg or chest, and surgically attaching it across a severely narrowed or blocked coronary artery, thus "bypassing" the blockage. These "new" blood vessels carry blood around the obstruction, so that the blood supply to and from the heart is restored

Coronary artery disease develops when one or more of the coronary arteries that supply the blood to the heart become narrower than they used to be, due to the buildup of cholesterol and other substances in the wall of the artery. This affects the blood flow to the heart muscle. Without an adequate blood supply, heart muscle tissue can be damaged.

Deposits of cholesterol and other fat-like substances can build up in the inner lining of these blood vessels and become coated with scar tissue, forming a cholesterol-rich bump in the blood vessel wall known as plaque. Plaque buildup narrows and hardens the blood vessel, a process called atherosclerosis, or hardening of the arteries.

Eventually these plaque deposits can build up to significantly reduce or block blood flow to the heart. A person may experience chest pain or discomfort from inadequate blood flow to the heart, especially during exercise when the heart needs more oxygen. This is known as angina.

When Is Bypass Surgery Offered?    

Bypass surgery is usually performed when a person has two or three blood vessels with blockages, or when the major vessel has a severe blockage. Therefore, bypass surgery may be advised in the following situations:

• When there is severe narrowing of the left main coronary artery (because this major artery branches into several others, putting too much of the heart at risk if the angioplasty were to fail)

• If there is severe narrowing of any three arteries in a person who also has a weakly pumping heart

• If there is severe narrowing of the left anterior descending artery and at least one other coronary artery, plus either diabetes or a weakly pumping heart

• Following failed coronary angioplasty, a procedure performed to widen a narrowed coronary artery by inserting a balloon-tipped tube into the artery and inflating the balloon.

How Does Bypass Surgery Help?

After bypass surgery, the blood supply to the area of the heart that was previously restricted due to narrowing of the artery supplying that area, is restored. The blocked artery has now been bypassed.

Bypass surgery may improve quality of life and increase the life span. In some cases, it may do both. In other cases, it may only improve the quality of life.

The important thing to remember is that surgery is not a cure, but just keeps the problem under control. Once your surgeon has done the procedure, there are choices you may take to prevent the condition from recurring (coming back). How healthy you are after surgery depends in large part on the steps you take to prevent future problems.