In coronary artery by-pass surgery the blood vessel to be used as graft has to be:

Explanation

In coronary artery bypass surgery, a blood vessel from another part of the body is used as a graft to bypass a blocked or narrowed coronary artery. The blood vessel used as a graft can be a vein from the leg, an artery from the forearm, or an artery from the mammary region of the chest.