Coronary artery bypass graft surgery (CABG) is a procedure used to treat coronary artery disease. Coronary artery disease (CAD) is the narrowing of the coronary arteries – the blood vessels that supply oxygen and nutrients to the heart muscle. CAD is caused by a build-up of fatty material within the walls of the arteries. This build-up narrows the inside of the arteries, limiting the supply of oxygen-rich blood to the heart muscle.One way to treat the blocked or narrowed arteries is to bypass the blocked portion of the coronary artery with a piece of a healthy blood vessel from elsewhere in your body. 

Heart Bypass surgery

Before your surgery, you will get general anesthesia. You will be asleep (unconscious) and pain-free during surgery.Once you are unconscious, the heart surgeon will make an 8 to 10-inch (20.5 to 25.5 cm) surgical cut in the middle of your chest. Your breastbone will be separated to create an opening. This allows your surgeon to see your heart and aorta, the main blood vessel leading from the heart to the rest of your body.Most people who have coronary bypass surgery are connected to a heart-lung bypass machine, or bypass pump.

• Your heart is stopped while you are connected to this machine.
• This machine does the work of your heart and lungs while your heart is stopped for the surgery. The machine adds oxygen to your blood, moves blood through your body, and removes carbon dioxide.

Another type of bypass surgery does not use the heart-lung bypass machine. The procedure is done while your heart is still beating. This is called off-pump coronary artery bypass, or OPCAB.

What are the different types of heart bypass surgery?

Your doctor will recommend a certain type of bypass surgery depending on how many of your arteries are blocked.

• Single bypass. Only one artery is blocked.
• Double bypass. Two arteries are blocked.
• Triple bypass. Three arteries are blocked.
• Quadruple bypass. Four arteries are blocked

Your risk of having a heart attack, heart failure, or another cardiac issue depends on the number of arteries blocked. Blockage in more arteries also means that the surgery may take longer or become more complex.

To Create The Bypass Graft:.

• The doctor will take a vein or artery from another part of your body and use it to make a detour (or graft) around the blocked area in your artery. Your doctor may use a vein, called the saphenous vein, from your leg.
• To reach this vein, a surgical cut will be made along the inside of your leg, between your ankle and groin. One end of the graft will be sewn to your coronary artery. The other end will be sewn to an opening made in your aorta.
• A blood vessel in your chest, called the internal mammary artery (IMA), can also be used as the graft. One end of this artery is already connected to a branch of your aorta. The other end is attached to your coronary artery.
• Other arteries can also be used for grafts in bypass surgery. The most common one is the radial artery in your wrist.

After the graft has been created, your breastbone will be closed with wires. These wires stay inside you. The surgical cut will be closed with stitches.This surgery can take 4 to 6 hours. After the surgery, you will be taken to the intensive care unit.