What happens if you do not amputate a leg that has no blood flow below the knee?

Blood flow: Our bodies need blood flow to survive or a process called gangrenous necrosis or death occurs. Blood brings oxygen, nutrients, the immune system, and carries waste and carbon dioxide away. Sometimes for a person to survive surgeons will tell a patient an amputation is necessary. While difficult to accept in some cases, it is a wise decision when necessary. Vascular surgery not always possible.