Double bypass surgery is a serious but common open heart surgery procedure. To understand a double bypass, you first need to understand some things about the anatomy of the heart and heart disease.
The blood vessels that supply the heart with its own blood supply are called the coronary arteries. In some people, the coronary arteries become blocked. If a blockage is severe, it can completely stop blood flow to the area of the heart that is fed by that particular blood vessel. This blockage can then cause a heart attack.
In many cases, coronary artery disease can be treated with medication, lifestyle changes and alternative procedures. For patients with blockage(s) that are severe, surgery may be necessary to make sure the heart continues to receive adequate blood flow. This surgery is known as coronary artery bypass surgery (CABG).
During the procedure, blood vessels are taken from another area of the body, typically the leg, and grafted onto the existing heart vessel before and after the blockage. The blood is literally being rerouted around the blockage then returning to the vessel.
If two vessels are blocked and need to be bypassed, the surgery is referred to as a double bypass because two grafts are performed. If three vessels are bypassed the surgery is called a triple bypass, and so on.
Sources: What Is Coronary Artery Bypass Grafting? National Heart Lung and Blood Institute. Accessed 2009. http://www.nhlbi.nih.gov/health/dci/Diseases/cabg/cabg_whatis.html
What Is Coronary Artery Bypass Grafting? National Heart Lung and Blood Institute. Accessed 2009. http://www.nhlbi.nih.gov/health/dci/Diseases/cabg/cabg_whatis.html