What is the etiology of coronary bypass surgery?

I imagine you are referring to a Quintuple Bypass (Coronary Artery Bypass Graft - CABG). See this page: http://en.wikipedia.org/wiki/Coronary_artery_bypass_surgery

Coronary artery bypass graft surgery is a surgical procedure in which one or more blocked coronary arteries are bypassed by a blood vessel graft to restore normal blood flow to the heart.

Coronary artery bypass surgery is an operation in which a blood vessel (often a long vein surgically removed from the leg) is grafted onto the blocked artery to bypass the blocked portion.

The average time required for coronary bypass surgery is four hours.

relieves chest pain and reduces risk of a heart attack by using a different vein or artery for blood circulation in the heart. The current vien would be blocked by fatty deposits therefore requiring...