Blood clots may form in the legs as you stay still during or after surgery. The blood clot can move to the heart causing a heart attack or to the lungs, causing pulmonary embolism, which can be fatal. Walking as soon as possible after surgery helps to prevent blood clots.<B> </B>Use of compressive leg stockings and blood thinners, such as enoxaparin and heparin, also help to prevent blood clots in the legs.