Cardiac bypass surgery is a process that restores the flow of blood to the heart when one or more arteries have become blocked. Blood veins from other parts of the body, like the chest and legs, are used to go around these arteries. The blood vessels go around the blocked artery to make new ways for oxygen-rich blood to get to the heart.
The blood flow to the heart is fixed and made better by these blood channels. Most of the time, this surgery is done with the heart stopped, which requires cardiac bypass. There are ways to do bypass surgery while the heart is still beating, which is called "off-pump" surgery. A patient may need one, two, three, or more bypasses, depending on how many coronary arteries are blocked.