The word by-pass is English and means bypass, diversion. This term is used to name different methods consist essentially in the channeling of fluid through a secondary route through the main valve opening and closing. In the field of hydraulics, the by-pass pipe is occasionally used to divert and regulate fluid flow. In the area of surgery is a technique used when there is interruption of blood flow obstruction in an artery. It is possible to graft a small tube, which can be plastic or a portion of a vein in the body (usually transplanted veins from the thighs). Among the different by-pass the blood are performed in the case of clogged arteries in the heart or brain and stomach, made for the treatment of obesity, namely reducing the stomach's ability to that the patient reduce the amount of food eaten.
This procedure was first practiced in the 70s, in patients with blocked coronary arteries.